Research ArticleImpact of Gastrointestinal In Vitro Digestion and DeficitIrrigation on Antioxidant Activity and Phenolic ContentBioaccessibility of ldquoManzanillardquo Table Olives

LucıaSanchez-Rodrıguez1MarinaCano-Lamadrid 2 AngelACarbonell-Barrachina 1

Francisca Hernandez2 and Esther Sendra3

1Departamento de Tecnologıa Agroalimentaria Grupo de Calidad y Seguridad AlimentariaEscuela Politecnica Superior de Orihuela Universidad Miguel Hernendez de Elche Carretera de Beniel km 32 Orihuela 03312Alicante Spain2Departamento de Produccion Vegetal y Microbiologıa Grupo Produccion Vegetal Escuela Politecnica Superior de OrihuelaUniversidad Miguel Hernandez de Elche Carretera de Beniel Km 32 03312-Orihuela Alicante Spain3Departamento de Tecnologıa Agroalimentaria Grupo de Calidad y Seguridad AlimentariaEscuela Politecnica Superior de Orihuela Universidad Miguel Hernendez de Elche Carretera de Beniel km 32 Orihuela 03312Alicante Spain

Correspondence should be addressed to Angel A Carbonell-Barrachina angelcarbonellumhes

Received 18 December 2019 Revised 18 February 2020 Accepted 2 March 2020 Published 1 April 2020

Academic Editor Flora V Romeo

Copyright copy 2020 Lucıa Sanchez-Rodrıguez et al-is is an open access article distributed under the Creative CommonsAttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

-is was the first study investigating the polyphenol content antioxidant potential and polyphenol bioaccessibility after in vitrodigestion of table olives grown using regulated deficit irrigation (RDI) treatments to save irrigation water Two experiments werecarried out (i) experiment A where RDI was applied during the pit hardening stage and (ii) experiment B where RDI was appliedduring the rehydration stage Only slight differences among irrigation treatments were observed in two antioxidant assays(ABTS+bull and DPPHbull) and on TPC for the soluble fraction after in vitro digestion An average of 1 g gallic acid equivalents kgminus 1 oftable olives were found after digestion Approximately 12 of the polyphenols of table olives were bioaccessible for humanabsorption Saving water techniques influence neither the final polyphenol content and antioxidant potential of table olives northe bioaccessibility of polyphenols -e consumption of 40 g of table olives will provide 40mg of bioaccessible polyphenols able toprovide associated health benefits (sim7 of the daily polyphenols intake recommendation)

1 Introduction

Table olives are a common constituent of Mediterranean dietand have beneficial effects on human health because they areantioxidant-rich foods [1] Olives are rich in polyphenols (1-2 of its composition) and these compounds provide an-tioxidant anti-inflamatory and antitumoral properties totable olives Olive composition can be affected by severalfactors such as climate agronomic conditions and theprocessing method [2] Nowadays regulated deficit irri-gation (RDI) strategies are being implemented on olive treeorchards with the main purpose of saving water Addi-tionally moderate RDI strategies are being investigated in

table olives due to their ldquopotentialrdquo effect on enhancing theaccumulation of bioactive compounds and improvement ofthe intensity of key sensory attributes these special tableolives are known as hydroSOStainable [3]

Studying the bioaccessibility of antioxidant and poly-phenolic compounds is crucial to know their real behaviorand activity in vivo Bioaccessibility is defined as the ten-dency of compounds to be extracted from the food matrixand then be available for intestinal cell absorption [1] Forthat purpose gastrointestinal in vitro digestion simulation isa model to extract compounds from the test matrix simu-lating human digestion and although it is important toconsider that several factors (gender age intestinal

HindawiJournal of Food QualityVolume 2020 Article ID 6348194 6 pageshttpsdoiorg10115520206348194

conditions etc) will affect digestion this model is still agood alternative to avoid animal testing methods andpromote animal protection [4]

In the present research ldquoManzanillardquo Spanish-style tableolives grown under different RDI strategies (experiment Awater irrigation was reduced during the pit hardening stageexperiment B water irrigation was reduced during the re-hydration stage) were subjected to a gastrointestinal in vitrodigestion simulation with the purpose to study how the lackof water during cultivation affects the polyphenol contentpolyphenol bioaccessibility and antioxidant activity by threemethods after simulation of human digestion

2 Materials and Methods

21 Experimental Conditions and Irrigation TreatmentsTwo irrigation experiments were carried out in this study oncultivar ldquoManzanillardquo to evaluate the effect of water stress attwo phenological stages

211 Experiment A

(i) A0 (optimumwater status) trees were fully irrigated(ii) A1 (moderate deficit irrigation) the threshold value

for water stress level (ψstem) was minus 2MPa during thepit hardening stage (day of the year (DOY) 169 toDOY 240)

(iii) A2 (severe deficit irrigation (short time)) thethreshold value for ψstem was minus 3MPa during halfperiod of the pit hardening stage (from DOY 169 toDOY 206)

(iv) A3 (severe deficit irrigation (long time)) thethreshold value for ψstem was minus 3MPa until end ofperiod of the pit hardening stage (DOY 169 to DOY240)

212 Experiment B

(i) B0 (optimumwater status) trees were fully irrigated(ii) B1 (moderate deficit irrigation before harvest (short

time)) the threshold value for ψstem was minus 2MPa atthe beginning of September without the rehydrationperiod (2 weeks before harvest)

(iii) B2 (moderate deficit irrigation (long time)) thethreshold value for ψstem was minus 2MPa from mid-August without the rehydration period (four weeksbefore harvest)

Experiment A was carried out in a farm located in DosHermanas (Seville Spain 37deg25primeN 5deg95primeW) ldquoManzanillardquoolive trees were sim30 years old and were spacing following a7times 4 square pattern Irrigation was performed at night bydrip with one lateral pipe per row of trees and four emitters(each delivering 2 L hminus 1) per plant

With respect to experiment B the farm was located inCoria del Rıo (Seville Spain 37deg17primeN 6deg3primeW) ldquoManzanillardquoolive trees were sim44 years old and were spacing following a7times 5m square pattern Also irrigation was carried out

during night by one lateral pipe per tree row and fiveemitters (each delivering 8 L hminus 1) per plant Specificagronomy characteristics could be found in [5] Differentlocations were used because of land availability although asexplained before similar conditions characterized the fieldand weather

Field characteristics of both experiments could be foundin the work by Sanchez-Rodrıguez and Cano-Lamadrid et al[3] Climatic conditions could be considered equal for bothexperiments because only 10 km separated the farms A totalrainfall amount of 25894mm was registered on experimentA from 3 September 2015 to 20 September 2016 while25425mm of total rainfall amount on experiment B from 8September 2015 to 27 September 2016 Winter minimumtemperatures were around 0degC and spring temperaturesdetermine flowering around mid-April Pest controlpruning and fertilization practices were those commonlyused by growers

Stress integral (Ψint) was calculated to study the accu-mulative stress of olive trees produced du to reduction ofwater irrigation [6]

Ψint 1113944Ψ minus (minus 02)1113872 1113873 times n11138681113868111386811138681113868

11138681113868111386811138681113868 (1)

whereΨint is the stress integralΨ is the average midday stemwater potential for any interval and n is the number of daysof the interval

Olives were collected by hand at their mature-green stageon September 2016

22 ldquoSpanish-Stylerdquo Processing Raw olives were processedfollowing ldquoSpanish-Stylerdquo to table olives as previous de-scribed in [7] Briefly raw olives were treated with NaOHsolution (13ndash26 weightvolume) for 6ndash8 h with the pur-pose to remove oleuropein and then olives were washedwith water for 12ndash14 h to remove residual NaOH Oliveswere put on 10ndash12 NaCl solution for fermentation untiltable olives-brine equilibrium was reached (pHlt 42 8ndash9(weightvolume) NaCl 07ndash10 lactic acid and residualalkalinitylt 0120N)

23 Gastrointestinal In Vitro Digestion Simulation In vitrodigestion simulation was carried out following the methoddescribed in [8] on table olives of all irrigation treatmentsunder study Firstly salivary solution simulation (SSS)gastric solution simulation (GSS) and intestinal solutionsimulation (ISS) were carried out using KCl (05M)KH2PO4 (05M) NaHCO3 (1M) NaCl (2M) MgCl2(H2O)6 (015M) and (NH4)2CO3 (05M) following indi-cations in [8] Simulation of the oral phase was carried outwith 10 g of table olives and simulating mastication withα-amylase (1500U mLminus 1) (Enzyme Commission (EC)number 3211) and SSS -e mixture was placed in astomacher bag and stomached for 10 minutes to simulate themastication (Stomacher Laboratory Blender Bioxia -aneIndia) -e resulting mixture was transferred to a glassbottle -en the gastric phase was carried out with pepsin(2500UmLminus 1) (EC number 34231) for 1 h at 37degC 170 rpm

2 Journal of Food Quality

(-ermostatic bath with agitation BSH Raypa BarcelonaEspantildea) and pH 3 (adjusted with HCl 6M) and GSS Fi-nally the intestinal step was performed with ISS pancreatin(800U mLminus 1) (EC Number 2324689) and bile salts(160mM) at 37degC 170 rpm and pH 7 (adjusted with NaOH1M) for 2 hours After the intestinal phase liquid solublefraction (SF) and solid residual fraction (RF) were collected-e SF was centrifuged at 10000 rpm for 10min at 4degC(Sigma 3ndash18K Sigma Laborzentrifugen Germany) for lateranalysis

24 Antioxidant Activity and Total Phenolic ContentNondigested table olives (test matrix (TM)) and RF wereextracted as described by previous authors [9] Briefly 2 g offresh sample was mixed with 10mL of MeOHwater (80 20vv) + 1 HCl -is mixture was sonicated for 15min andthen it was left overnight at 4degC -e next day samples weresonicated again for 15min and centrifuged at 10000 rpm for10min at 4degC (Sigma 3ndash18K Sigma LaborzentrifugenGermany)

Antioxidant activity of TM SF and RF was measuredusing three assays (i) ABTS+bull as reported in [10] (ii) DPPHbull

as reported in [11] and (iii) FRAP following protocol in [12]Additionally TPC assay was carried out as in [13] Allanalyses were performed using an UV-visible spectropho-tometer (Helios Gamma model UVG 1002E) Results forantioxidant activity were quantified using calibration curveswith Trolox and expressed as mmol Trolox kgminus 1 of tableolives TPC calibration curves were obtained with gallic acidand results were expressed as gallic acid equivalents (GAE)g kgminus 1 of table olives

TPC bioaccessibility expressed as the percentage of totalpolyphenols liberated from the TM after the gastrointestinaldigestion was calculated as previously reported by [14]

Bioaccessibility() CFCI times 100 (2)

where CF is the polyphenols concentration in the SF fractionand CI is the initial polyphenols concentration in undigestedflesh table olives

25 Statistical Analysis One-way analysis of variance(ANOVA) was carried out to study the effect of RDItreatment and then Tukeyrsquos multiple range test was used tocompare the means -e standard deviation (SD) of themean is used to perform Tukeyrsquos test therefore the SDvalues were not included in tables to avoid repetition of thedata and to make tables easier to understand Statisticaldifferences were considered significant at three levels (i)plt 005 (lowast) (ii) plt 001 (lowastlowast) and (iii) plt 0001 (lowastlowastlowast) AnXLSTAT (20160227444 version Addinsoft) was used toperform all statistical analysis

3 Results and Discussion

31 Irrigation As can be seen in Table 1 different levels ofwater stress were reached by olive trees In experiment A itcould be found that A0 presented the lowest Ψint because itwas not submitted to stress (control treatment) -e A1(moderate deficit irrigation) and A2 (severe deficit irrigationduring short time) trees had intermediate and equivalent Ψintvalues while A3 (severe deficit irrigation during long time)trees presented the highest Ψint value In experiment B al-though B0 (control) was fully irrigated it could be seen that itsΨint value was higher than that of B1 (moderate deficit ir-rigation during short time before harvest) -is experimentalfact can be justified because even though researchers cancontrol the applied water volume other natural factors suchas overall weather (eg rain) or soil differences among areasof the same field can also significantly affect Ψint Finally B2presented the highest Ψint value due to water stress wasmoderate but during a long time before harvest

32 Antioxidant Activity and Total Phenolic ContentResults of antioxidant activity and TPC of table olives understudy are shown in Table 2 In experiment A no statisticaldifferences were found among irrigation treatments in theantioxidant activity of the TM Regarding ABTS+bull assay inthe SF and total (SF +RF) fractions it was found that thehigher the stress the higher the antioxidant potential Withrespect to the percentage of variation ( var) after gas-trointestinal in vitro digestion for ABTS+bull it was found adecrease of sim76 and the smallest decrease was found for A3table olives (those with the highest water stress) RegardingDPPHbull in the SF and total fractions the highest value wasfound on A1 at a moderate stress level while olives from theA3 treatment (highest water stress) showed a decrease onDPPHbull in comparison to control (A0) -e DPPHbull varwas higher than that of ABTS+bull with a sim95 decrease FRAPassay did not show statistical differences in any fractionunder study and the var was sim92 Concerning TPC onlySF showed statistical differences between irrigation treat-ments and a small increase (28) was found betweencontrol and three RDI table olives A decrease of sim82 wasfound with respect to the variation percentage

Regarding experiment B TM showed statistical differ-ences on DPPHbull and FRAP assays as well as on TPC ForDPPHbull and TPC both RDI treatments showed higher valuesthan control being the highest B1 while in FRAP assay B1

Table 1 Watering technique conditions of ldquoManzanillardquo tableolives of experiment A and experiment B

Stress integral (MPa x day)Experiment A

ANOVAdagger lowast

A0 296 bDagger

A1 626 abA2 504 abA3 874 a

Experiment BANOVA lowast

B0 757 abB1 629 bB2 855 adaggerlowastSignificant at plt 005 DaggerValues followed by the same letter within thesame column and experiment were not significantly different (plt 005)according to Tukeyrsquos least significant difference test

Journal of Food Quality 3

was the treatment that presented the lowest value No sta-tistical differences between treatments were found aftergastrointestinal in vitro digestion simulation for this ex-periment For ABTS+bull it was found an average of 14mmolTrolox kgminus 1 of total fraction and a var of simminus 85 ForDPPHbull values showed an average of 04mmol Trolox kgminus 1

for total fraction with a var of simminus 95 With respect toFRAP assay total fraction showed an average of 131mmolTrolox kgminus 1 and a var of simminus 93 Finally average TPC was099 g GAE kgminus 1 and TPC had a var of simminus 83

Although no statistical differences between irrigationtreatments were found on RF some assays showed highervalues than control such as DPPHbull (sim04mmol Trolox kgminus 1)and TPC (sim03 g GAE kgminus 1) -ose values could be relevant

because they might indicate that there are still antioxidantand polyphenolic compounds that could be metabolized bythe colon microflora and thus it points to a potential in-crease in bioavailability -erefore RF values found on tableolives coming from deficit irrigation strategies indicated thatstress caused on plant could affect the final bioavailability ofantioxidants and polyphenols increasing the content of thesecompounds available for human absorption [15]

Figure 1 represents the percentage of bioaccessibility ofTPC after the gastrointestinal in vitro digestion simulationIn both experiments no statistically significant differenceswere found among irrigation treatments In experiment AA0 presented 115 A1 111 A2 121 and A3 131 ofTPC bioaccessibility In experiment B control (B0) was

Table 2 Antioxidant activity (ABTS+bull DPPH and FRAP) and Total Phenolic Content (TPC) of ldquoManzanillardquo table olives before and aftergastrointestinal in vitro simulation digestion of experiment A and experiment B

Antioxidant activity (mmol trolox eq kg-1)TPC (g GAE kg-1)

ABTS+bull DPPHbull FRAPTM SF RF Total var TM SF RF Total var TM SF RF Total var TM SF RF Total var

Experiment AANOVAdagger NS lowastlowast NS lowast NS lowastlowastlowast NS lowast NS NS NS NS NS lowastlowast NS NS

A0 661 134bDagger 011 145

b minus 781 121 051ab 008 059

ab minus 951 154 106 020 125 minus 919 617 070b 042 113 minus 817

A1 748 156ab 013 169

ab minus 774 130 060a 026 087

a minus 933 160 075 022 097 minus 939 646 072a 033 105 minus 837

A2 707 143ab 011 153

b minus 784 125 037bc 009 047

ab minus 962 148 089 023 112 minus 924 590 072a 028 099 minus 832

A3 719 171a 025 198

a minus 725 112 025c 000 019

b minus 983 155 095 022 117 minus 925 547 072a 030 102 minus 814

Experiment BANOVA NS NS NS NS lowast NS NS NS lowastlowast NS NS NS lowastlowast NS NS NS

B0 874 123 005 129 minus 852 731c 047 000 047 minus 936 191

a 099 022 121 minus 937 546c 072 023 095 minus 826

B1 941 154 007 162 minus 828 964a 034 000 034 minus 965 178

b 112 024 136 minus 924 590a 072 034 105 minus 822

B2 934 126 006 132 minus 859 862b 031 000 031 minus 964 193

a 112 024 136 minus 930 583b 072 024 096 minus 835

daggerNSnot significant at plt 005 lowast lowastlowast and lowastlowastlowastsignificant at plt 005 001 and 0001 respectively DaggerValues followed by the same letter within the same columnwere not significantly different (plt 005) according to Tukeyrsquos least significant difference test Note TM test matrix SF soluble fraction liquid RF residualfraction solid Total SF +RF var ( variation) percentage of variation between the initial values and the values obtained after digestion

0

2

4

6

8

10

12

14

A0 A1 A2 A3

B

ioac

cess

ibili

ty

Experiment A

(a)

B0 B1 B20

2

4

6

8

10

12

14

B

ioac

cess

ibili

ty

Experiment B

(b)

Figure 1 Total phenol content bioaccessibility after gastrointestinal in vitro digestion simulation of ldquoManzanillardquo table olives of experimentA (a) ( ) and experiment B (b) ( ) Columns followed by the same letter within the same experiment were not significantly different(plt 005) according to Tukeyrsquos least significant difference test

4 Journal of Food Quality

132 bioaccessible while B1 and B2 treatments showed122 and 123 of TPC bioaccessibility respectively

-e decrease on antioxidant capacity and phenoliccompounds content may be related to their degradation Ahigh proportion of table olive polyphenols are very sus-ceptible to chemical degradation when they are submitted tothe acidic conditions of digestion [15] It was formerlydescribed the polyphenolic profile of hydroSOStainable tableolives of the current research [3] and it was found an in-crease of oleuropein comselogoside and verbascoside on A1treatment as compared with control as well as an increase ofelenoic acid glucoside oleuropein and comselogoside re-garding RDI treatments of experiment B Beside this in-creases it was previously reported that only 25 ofoleuropein (one of the most important polyphenols in tableolives) was stable during digestion as well as only 20 ofcomselogoside and elenoic acid derivatives [15] Flavonoidsverbascoside and hydroxytyrosol derivatives also presenteda small TPC bioaccessibility in a research conducted withthree table olives cultivars [14] Flavonoids are not verysoluble in either organic or aqueous solvents and are usuallypresent in foods in combination with sugars in the form ofglycosides [16] so it is possible that higher concentrationsthat were found on RDI table olives on some flavonoids suchas luteolin [3] would probably not have been extracted fromthe olive pulp during the in vitro digestion simulation

Similar results to the ones reported in the current studyhave been previously reported in ldquoCornezuelordquo table olives[15] For instance it was found a high decrease of DPPHbull

and ABTS+bull after gastrointestinal digestion simulation andalso a decrease of 75 of TPC

Several factors can influence the phenolic bioaccessibility-e digestion process could produce changes on polyphenolcomposition modifying their original profile -e food matrixwhere polyphenols are found could also influence the extraction[16] It has been previously reported that the fermentationprocess suffered during table olives preparation and the olivecultivar could influence the final polyphenol extraction [14]

-ere is lack of information about the how the stresssuffered by plants is related to the later metabolism of thecompounds by human digestive apparatus In the presentresearch the water stress suffered by olive trees due to ir-rigation strategies did not provide significant differencesamong treatments on final TPC and bioaccessibility in bothexperiments It has been demonstrated that it is possible tosave irrigation water without having significant effect on thefinal polyphenolic compounds available for human ab-sorption Daily intake of polyphenolic compounds is veryimportant because of their associated health benefits Highertotal consumption of 600mg per day would provide aprotective effect against chronic diseases [17] Consequentlyeating 10 hydroSOStainable table olives per day (40mg ofbioaccessible polyphenols) would contribute to a sim7 of thistotal polyphenol intake recommendation

4 Conclusions

-is is the first study investigating the effect of gastroin-testinal in vitro digestion simulation on antioxidant

potential and total polyphenol content and its bio-accessibility of table olives submitted to regulated deficitirrigation strategies Water stress was applied during twogrowing stages experiment A the pit hardening stage andexperiment B during the rehydration phase Results showedthat in experiment B antioxidants and polyphenols werenot affected by the stress after gastrointestinal in vitro di-gestion simulation while in experiment A regarding TPCABTS+bull and DPPHbull slight differences were found amongtreatments In general a total of sim1 g GAE kgminus 1 was extractedafter digestion indicating that the bioaccessibility of the TPCof both control and hydroSOStainable table olives was sim12-erefore the daily intake of 10 hydroSOStainable tableolives entails the intake of 40mg of ldquobioaccessiblerdquo poly-phenols and involve the daily of sim7 of polyphenols intakerecommendation for protective effect against chronicdiseases

Data Availability

-e data used to support the findings of this study are in-cluded within the article

Conflicts of Interest

-e authors declare that they have no conflicts of interest

Acknowledgments

-is study has been funded by (Ministerio de CienciaInnovacion (MCI) Agencia Estatal de Investigacion (AEI)and Fondo Europeo de Desarrollo Regional (FEDER))through a coordinated research project (hydroSOS mark)including the Universidad Miguel Hernandez de Elche(AGL2016-75794-C4-1-R hydroSOS foods) and the Uni-versidad de Sevilla (AGL2016-75794-C4-4-R) (MCIAEIFEDER UE) AuthorMarina Cano-Lamadrid was funded bya FPU grant from the Spanish Ministry of Education(FPU1502158)

References

[1] C Dinnella P Minichino A M DrsquoAndrea andE Monteleone ldquoBioaccessibility and antioxidant activitystability of phenolic compounds from extra-virgin olive oilsduring in vitro digestionrdquo Journal of Agricultural and FoodChemistry vol 55 no 21 pp 8423ndash8429 2007

[2] I DrsquoAntuono A Garbetta B Ciasca et al ldquoBiophenols fromtable olive cv bella di Cerignola chemical characterizationbioaccessibility and intestinal absorptionrdquo Journal of Agri-cultural and Food Chemistry vol 64 no 28 pp 5671ndash56782016

[3] L Sanchez-Rodrıguez M Cano-Lamadrid A A- Carbonell-Barrachina A Wojdyło E Sendra and F HernandezldquoPolyphenol profile in manzanilla table olives as affected bywater deficit during specific phenological stages and Spanish-style processingrdquo Journal of Agricultural and Food Chemistryvol 67 no 2 pp 661ndash670 2019

[4] M H Ahmad-Qasem J Canovas E Barrajon-CatalanJ E Carreres V Micol and J V Garcıa-Perez ldquoInfluence ofolive leaf processing on the bioaccessibility of bioactive

Journal of Food Quality 5

polyphenolsrdquo Journal of Agricultural and Food Chemistryvol 62 no 26 pp 6190ndash6198 2014

[5] M J Martın-Palomo M Corell I Giron et al ldquoAbsence ofyield reduction after controlled water stress during prehaverstperiod in table olive treesrdquo Agronomy vol 10 no 2 p 2582020

[6] B J Myers ldquoWater stress integral-a link between short-termstress and long-term growthrdquo Tree Physiology vol 4 no 4pp 315ndash323 1988

[7] L Sanchez-Rodrıguez L Lipan L Andreu et al ldquoEffect ofregulated deficit irrigation on the quality of raw and tableolivesrdquo Agricultural Water Management vol 221 pp 415ndash421 2019

[8] M Minekus M Alminger P Alvito et al ldquoA standardisedstaticin vitrodigestion method suitable for foodmdashan inter-national consensusrdquo Food and Function vol 5 no 6pp 1113ndash1124 2014

[9] M Cano-Lamadrid F Hernandez M Corell et al ldquoAnti-oxidant capacity fatty acids profile and descriptive sensoryanalysis of table olives as affected by deficit irrigationrdquo Journalof the Science of Food and Agriculture vol 97 no 2pp 444ndash451 2017

[10] R Re N Pellegrini A Proteggente A Pannala M Yang andC Rice-Evans ldquoAntioxidant activity applying an improvedABTS radical cation decolorization assayrdquo Free Radical Bi-ology and Medicine vol 26 no 9-10 pp 1231ndash1237 1999

[11] W Brand-Williams M E Cuvelier and C Berset ldquoUse of afree radical method to evaluate antioxidant activityrdquoLWTmdashFood Science and Technology vol 28 no 1 pp 25ndash301995

[12] I F F Benzie and J J Strain ldquo-e ferric reducing ability ofplasma (FRAP) as a measure of ldquoantioxidant powerrdquo theFRAP assayrdquo Analytical Biochemistry vol 239 no 1pp 70ndash76 1996

[13] X GaoM Ohlander N Jeppsson L Bjork and V TrajkovskildquoChanges in antioxidant effects and their relationship tophytonutrients in fruits of sea buckthorn (Hippophae rham-noides L) during maturationrdquo Journal of Agricultural andFood Chemistry vol 48 no 5 pp 1485ndash1490 2000

[14] I DrsquoAntuono A Bruno V Linsalata et al ldquoFermentedApulian table olives effect of selected microbial starters onpolyphenols composition antioxidant activities and bio-accessibilityrdquo Food Chemistry vol 248 pp 137ndash145 2018

[15] M P Fernandez-Poyatos A Ruiz-Medina and E J Llorent-Martınez ldquoPhytochemical profile mineral content and an-tioxidant activity of Olea europaea L Cv Cornezuelo tableolives Influence of in vitro simulated gastrointestinal diges-tionrdquo Food Chemistry vol 297 Article ID 124933 2019

[16] F A Tomas-Barberan ldquoLos polifenoles de los alimentos y lasaludrdquo Alimentacion Nutricion Y Salud vol 10 no 2pp 41ndash53 2006

[17] I Navarro Gonzalez M J Periago and F J Garcıa AlonsoldquoEstimacion de la ingesta diaria de compuestos fenolicos en lapoblacion espantildeolardquo Revista Espantildeola de Nutricion HumanaY Dietetica vol 21 no 4 pp 320ndash326 2017

6 Journal of Food Quality

(-ermostatic bath with agitation BSH Raypa BarcelonaEspantildea) and pH 3 (adjusted with HCl 6M) and GSS Fi-nally the intestinal step was performed with ISS pancreatin(800U mLminus 1) (EC Number 2324689) and bile salts(160mM) at 37degC 170 rpm and pH 7 (adjusted with NaOH1M) for 2 hours After the intestinal phase liquid solublefraction (SF) and solid residual fraction (RF) were collected-e SF was centrifuged at 10000 rpm for 10min at 4degC(Sigma 3ndash18K Sigma Laborzentrifugen Germany) for lateranalysis

24 Antioxidant Activity and Total Phenolic ContentNondigested table olives (test matrix (TM)) and RF wereextracted as described by previous authors [9] Briefly 2 g offresh sample was mixed with 10mL of MeOHwater (80 20vv) + 1 HCl -is mixture was sonicated for 15min andthen it was left overnight at 4degC -e next day samples weresonicated again for 15min and centrifuged at 10000 rpm for10min at 4degC (Sigma 3ndash18K Sigma LaborzentrifugenGermany)

Antioxidant activity of TM SF and RF was measuredusing three assays (i) ABTS+bull as reported in [10] (ii) DPPHbull

as reported in [11] and (iii) FRAP following protocol in [12]Additionally TPC assay was carried out as in [13] Allanalyses were performed using an UV-visible spectropho-tometer (Helios Gamma model UVG 1002E) Results forantioxidant activity were quantified using calibration curveswith Trolox and expressed as mmol Trolox kgminus 1 of tableolives TPC calibration curves were obtained with gallic acidand results were expressed as gallic acid equivalents (GAE)g kgminus 1 of table olives

TPC bioaccessibility expressed as the percentage of totalpolyphenols liberated from the TM after the gastrointestinaldigestion was calculated as previously reported by [14]

Bioaccessibility() CFCI times 100 (2)

where CF is the polyphenols concentration in the SF fractionand CI is the initial polyphenols concentration in undigestedflesh table olives

25 Statistical Analysis One-way analysis of variance(ANOVA) was carried out to study the effect of RDItreatment and then Tukeyrsquos multiple range test was used tocompare the means -e standard deviation (SD) of themean is used to perform Tukeyrsquos test therefore the SDvalues were not included in tables to avoid repetition of thedata and to make tables easier to understand Statisticaldifferences were considered significant at three levels (i)plt 005 (lowast) (ii) plt 001 (lowastlowast) and (iii) plt 0001 (lowastlowastlowast) AnXLSTAT (20160227444 version Addinsoft) was used toperform all statistical analysis

3 Results and Discussion

31 Irrigation As can be seen in Table 1 different levels ofwater stress were reached by olive trees In experiment A itcould be found that A0 presented the lowest Ψint because itwas not submitted to stress (control treatment) -e A1(moderate deficit irrigation) and A2 (severe deficit irrigationduring short time) trees had intermediate and equivalent Ψintvalues while A3 (severe deficit irrigation during long time)trees presented the highest Ψint value In experiment B al-though B0 (control) was fully irrigated it could be seen that itsΨint value was higher than that of B1 (moderate deficit ir-rigation during short time before harvest) -is experimentalfact can be justified because even though researchers cancontrol the applied water volume other natural factors suchas overall weather (eg rain) or soil differences among areasof the same field can also significantly affect Ψint Finally B2presented the highest Ψint value due to water stress wasmoderate but during a long time before harvest

32 Antioxidant Activity and Total Phenolic ContentResults of antioxidant activity and TPC of table olives understudy are shown in Table 2 In experiment A no statisticaldifferences were found among irrigation treatments in theantioxidant activity of the TM Regarding ABTS+bull assay inthe SF and total (SF +RF) fractions it was found that thehigher the stress the higher the antioxidant potential Withrespect to the percentage of variation ( var) after gas-trointestinal in vitro digestion for ABTS+bull it was found adecrease of sim76 and the smallest decrease was found for A3table olives (those with the highest water stress) RegardingDPPHbull in the SF and total fractions the highest value wasfound on A1 at a moderate stress level while olives from theA3 treatment (highest water stress) showed a decrease onDPPHbull in comparison to control (A0) -e DPPHbull varwas higher than that of ABTS+bull with a sim95 decrease FRAPassay did not show statistical differences in any fractionunder study and the var was sim92 Concerning TPC onlySF showed statistical differences between irrigation treat-ments and a small increase (28) was found betweencontrol and three RDI table olives A decrease of sim82 wasfound with respect to the variation percentage

Regarding experiment B TM showed statistical differ-ences on DPPHbull and FRAP assays as well as on TPC ForDPPHbull and TPC both RDI treatments showed higher valuesthan control being the highest B1 while in FRAP assay B1

Table 1 Watering technique conditions of ldquoManzanillardquo tableolives of experiment A and experiment B

Stress integral (MPa x day)Experiment A

ANOVAdagger lowast

A0 296 bDagger

A1 626 abA2 504 abA3 874 a

Experiment BANOVA lowast

B0 757 abB1 629 bB2 855 adaggerlowastSignificant at plt 005 DaggerValues followed by the same letter within thesame column and experiment were not significantly different (plt 005)according to Tukeyrsquos least significant difference test

Journal of Food Quality 3

was the treatment that presented the lowest value No sta-tistical differences between treatments were found aftergastrointestinal in vitro digestion simulation for this ex-periment For ABTS+bull it was found an average of 14mmolTrolox kgminus 1 of total fraction and a var of simminus 85 ForDPPHbull values showed an average of 04mmol Trolox kgminus 1

for total fraction with a var of simminus 95 With respect toFRAP assay total fraction showed an average of 131mmolTrolox kgminus 1 and a var of simminus 93 Finally average TPC was099 g GAE kgminus 1 and TPC had a var of simminus 83

Although no statistical differences between irrigationtreatments were found on RF some assays showed highervalues than control such as DPPHbull (sim04mmol Trolox kgminus 1)and TPC (sim03 g GAE kgminus 1) -ose values could be relevant

because they might indicate that there are still antioxidantand polyphenolic compounds that could be metabolized bythe colon microflora and thus it points to a potential in-crease in bioavailability -erefore RF values found on tableolives coming from deficit irrigation strategies indicated thatstress caused on plant could affect the final bioavailability ofantioxidants and polyphenols increasing the content of thesecompounds available for human absorption [15]

Figure 1 represents the percentage of bioaccessibility ofTPC after the gastrointestinal in vitro digestion simulationIn both experiments no statistically significant differenceswere found among irrigation treatments In experiment AA0 presented 115 A1 111 A2 121 and A3 131 ofTPC bioaccessibility In experiment B control (B0) was

Table 2 Antioxidant activity (ABTS+bull DPPH and FRAP) and Total Phenolic Content (TPC) of ldquoManzanillardquo table olives before and aftergastrointestinal in vitro simulation digestion of experiment A and experiment B

Antioxidant activity (mmol trolox eq kg-1)TPC (g GAE kg-1)

ABTS+bull DPPHbull FRAPTM SF RF Total var TM SF RF Total var TM SF RF Total var TM SF RF Total var

Experiment AANOVAdagger NS lowastlowast NS lowast NS lowastlowastlowast NS lowast NS NS NS NS NS lowastlowast NS NS

A0 661 134bDagger 011 145

b minus 781 121 051ab 008 059

ab minus 951 154 106 020 125 minus 919 617 070b 042 113 minus 817

A1 748 156ab 013 169

ab minus 774 130 060a 026 087

a minus 933 160 075 022 097 minus 939 646 072a 033 105 minus 837

A2 707 143ab 011 153

b minus 784 125 037bc 009 047

ab minus 962 148 089 023 112 minus 924 590 072a 028 099 minus 832

A3 719 171a 025 198

a minus 725 112 025c 000 019

b minus 983 155 095 022 117 minus 925 547 072a 030 102 minus 814

Experiment BANOVA NS NS NS NS lowast NS NS NS lowastlowast NS NS NS lowastlowast NS NS NS

B0 874 123 005 129 minus 852 731c 047 000 047 minus 936 191

a 099 022 121 minus 937 546c 072 023 095 minus 826

B1 941 154 007 162 minus 828 964a 034 000 034 minus 965 178

b 112 024 136 minus 924 590a 072 034 105 minus 822

B2 934 126 006 132 minus 859 862b 031 000 031 minus 964 193

a 112 024 136 minus 930 583b 072 024 096 minus 835

daggerNSnot significant at plt 005 lowast lowastlowast and lowastlowastlowastsignificant at plt 005 001 and 0001 respectively DaggerValues followed by the same letter within the same columnwere not significantly different (plt 005) according to Tukeyrsquos least significant difference test Note TM test matrix SF soluble fraction liquid RF residualfraction solid Total SF +RF var ( variation) percentage of variation between the initial values and the values obtained after digestion

0

2

4

6

8

10

12

14

A0 A1 A2 A3

B

ioac

cess

ibili

ty

Experiment A

(a)

B0 B1 B20

2

4

6

8

10

12

14

B

ioac

cess

ibili

ty

Experiment B

(b)

Figure 1 Total phenol content bioaccessibility after gastrointestinal in vitro digestion simulation of ldquoManzanillardquo table olives of experimentA (a) ( ) and experiment B (b) ( ) Columns followed by the same letter within the same experiment were not significantly different(plt 005) according to Tukeyrsquos least significant difference test

4 Journal of Food Quality

132 bioaccessible while B1 and B2 treatments showed122 and 123 of TPC bioaccessibility respectively

-e decrease on antioxidant capacity and phenoliccompounds content may be related to their degradation Ahigh proportion of table olive polyphenols are very sus-ceptible to chemical degradation when they are submitted tothe acidic conditions of digestion [15] It was formerlydescribed the polyphenolic profile of hydroSOStainable tableolives of the current research [3] and it was found an in-crease of oleuropein comselogoside and verbascoside on A1treatment as compared with control as well as an increase ofelenoic acid glucoside oleuropein and comselogoside re-garding RDI treatments of experiment B Beside this in-creases it was previously reported that only 25 ofoleuropein (one of the most important polyphenols in tableolives) was stable during digestion as well as only 20 ofcomselogoside and elenoic acid derivatives [15] Flavonoidsverbascoside and hydroxytyrosol derivatives also presenteda small TPC bioaccessibility in a research conducted withthree table olives cultivars [14] Flavonoids are not verysoluble in either organic or aqueous solvents and are usuallypresent in foods in combination with sugars in the form ofglycosides [16] so it is possible that higher concentrationsthat were found on RDI table olives on some flavonoids suchas luteolin [3] would probably not have been extracted fromthe olive pulp during the in vitro digestion simulation

Similar results to the ones reported in the current studyhave been previously reported in ldquoCornezuelordquo table olives[15] For instance it was found a high decrease of DPPHbull

and ABTS+bull after gastrointestinal digestion simulation andalso a decrease of 75 of TPC

Several factors can influence the phenolic bioaccessibility-e digestion process could produce changes on polyphenolcomposition modifying their original profile -e food matrixwhere polyphenols are found could also influence the extraction[16] It has been previously reported that the fermentationprocess suffered during table olives preparation and the olivecultivar could influence the final polyphenol extraction [14]

-ere is lack of information about the how the stresssuffered by plants is related to the later metabolism of thecompounds by human digestive apparatus In the presentresearch the water stress suffered by olive trees due to ir-rigation strategies did not provide significant differencesamong treatments on final TPC and bioaccessibility in bothexperiments It has been demonstrated that it is possible tosave irrigation water without having significant effect on thefinal polyphenolic compounds available for human ab-sorption Daily intake of polyphenolic compounds is veryimportant because of their associated health benefits Highertotal consumption of 600mg per day would provide aprotective effect against chronic diseases [17] Consequentlyeating 10 hydroSOStainable table olives per day (40mg ofbioaccessible polyphenols) would contribute to a sim7 of thistotal polyphenol intake recommendation

4 Conclusions

-is is the first study investigating the effect of gastroin-testinal in vitro digestion simulation on antioxidant

potential and total polyphenol content and its bio-accessibility of table olives submitted to regulated deficitirrigation strategies Water stress was applied during twogrowing stages experiment A the pit hardening stage andexperiment B during the rehydration phase Results showedthat in experiment B antioxidants and polyphenols werenot affected by the stress after gastrointestinal in vitro di-gestion simulation while in experiment A regarding TPCABTS+bull and DPPHbull slight differences were found amongtreatments In general a total of sim1 g GAE kgminus 1 was extractedafter digestion indicating that the bioaccessibility of the TPCof both control and hydroSOStainable table olives was sim12-erefore the daily intake of 10 hydroSOStainable tableolives entails the intake of 40mg of ldquobioaccessiblerdquo poly-phenols and involve the daily of sim7 of polyphenols intakerecommendation for protective effect against chronicdiseases

Data Availability

-e data used to support the findings of this study are in-cluded within the article

Conflicts of Interest

-e authors declare that they have no conflicts of interest

Acknowledgments

-is study has been funded by (Ministerio de CienciaInnovacion (MCI) Agencia Estatal de Investigacion (AEI)and Fondo Europeo de Desarrollo Regional (FEDER))through a coordinated research project (hydroSOS mark)including the Universidad Miguel Hernandez de Elche(AGL2016-75794-C4-1-R hydroSOS foods) and the Uni-versidad de Sevilla (AGL2016-75794-C4-4-R) (MCIAEIFEDER UE) AuthorMarina Cano-Lamadrid was funded bya FPU grant from the Spanish Ministry of Education(FPU1502158)

References

[1] C Dinnella P Minichino A M DrsquoAndrea andE Monteleone ldquoBioaccessibility and antioxidant activitystability of phenolic compounds from extra-virgin olive oilsduring in vitro digestionrdquo Journal of Agricultural and FoodChemistry vol 55 no 21 pp 8423ndash8429 2007

[2] I DrsquoAntuono A Garbetta B Ciasca et al ldquoBiophenols fromtable olive cv bella di Cerignola chemical characterizationbioaccessibility and intestinal absorptionrdquo Journal of Agri-cultural and Food Chemistry vol 64 no 28 pp 5671ndash56782016

[3] L Sanchez-Rodrıguez M Cano-Lamadrid A A- Carbonell-Barrachina A Wojdyło E Sendra and F HernandezldquoPolyphenol profile in manzanilla table olives as affected bywater deficit during specific phenological stages and Spanish-style processingrdquo Journal of Agricultural and Food Chemistryvol 67 no 2 pp 661ndash670 2019

[4] M H Ahmad-Qasem J Canovas E Barrajon-CatalanJ E Carreres V Micol and J V Garcıa-Perez ldquoInfluence ofolive leaf processing on the bioaccessibility of bioactive

Journal of Food Quality 5

polyphenolsrdquo Journal of Agricultural and Food Chemistryvol 62 no 26 pp 6190ndash6198 2014

[5] M J Martın-Palomo M Corell I Giron et al ldquoAbsence ofyield reduction after controlled water stress during prehaverstperiod in table olive treesrdquo Agronomy vol 10 no 2 p 2582020

[6] B J Myers ldquoWater stress integral-a link between short-termstress and long-term growthrdquo Tree Physiology vol 4 no 4pp 315ndash323 1988

[7] L Sanchez-Rodrıguez L Lipan L Andreu et al ldquoEffect ofregulated deficit irrigation on the quality of raw and tableolivesrdquo Agricultural Water Management vol 221 pp 415ndash421 2019

[8] M Minekus M Alminger P Alvito et al ldquoA standardisedstaticin vitrodigestion method suitable for foodmdashan inter-national consensusrdquo Food and Function vol 5 no 6pp 1113ndash1124 2014

[9] M Cano-Lamadrid F Hernandez M Corell et al ldquoAnti-oxidant capacity fatty acids profile and descriptive sensoryanalysis of table olives as affected by deficit irrigationrdquo Journalof the Science of Food and Agriculture vol 97 no 2pp 444ndash451 2017

[10] R Re N Pellegrini A Proteggente A Pannala M Yang andC Rice-Evans ldquoAntioxidant activity applying an improvedABTS radical cation decolorization assayrdquo Free Radical Bi-ology and Medicine vol 26 no 9-10 pp 1231ndash1237 1999

[11] W Brand-Williams M E Cuvelier and C Berset ldquoUse of afree radical method to evaluate antioxidant activityrdquoLWTmdashFood Science and Technology vol 28 no 1 pp 25ndash301995

[12] I F F Benzie and J J Strain ldquo-e ferric reducing ability ofplasma (FRAP) as a measure of ldquoantioxidant powerrdquo theFRAP assayrdquo Analytical Biochemistry vol 239 no 1pp 70ndash76 1996

[13] X GaoM Ohlander N Jeppsson L Bjork and V TrajkovskildquoChanges in antioxidant effects and their relationship tophytonutrients in fruits of sea buckthorn (Hippophae rham-noides L) during maturationrdquo Journal of Agricultural andFood Chemistry vol 48 no 5 pp 1485ndash1490 2000

[14] I DrsquoAntuono A Bruno V Linsalata et al ldquoFermentedApulian table olives effect of selected microbial starters onpolyphenols composition antioxidant activities and bio-accessibilityrdquo Food Chemistry vol 248 pp 137ndash145 2018

[15] M P Fernandez-Poyatos A Ruiz-Medina and E J Llorent-Martınez ldquoPhytochemical profile mineral content and an-tioxidant activity of Olea europaea L Cv Cornezuelo tableolives Influence of in vitro simulated gastrointestinal diges-tionrdquo Food Chemistry vol 297 Article ID 124933 2019

[16] F A Tomas-Barberan ldquoLos polifenoles de los alimentos y lasaludrdquo Alimentacion Nutricion Y Salud vol 10 no 2pp 41ndash53 2006

[17] I Navarro Gonzalez M J Periago and F J Garcıa AlonsoldquoEstimacion de la ingesta diaria de compuestos fenolicos en lapoblacion espantildeolardquo Revista Espantildeola de Nutricion HumanaY Dietetica vol 21 no 4 pp 320ndash326 2017

6 Journal of Food Quality

was the treatment that presented the lowest value No sta-tistical differences between treatments were found aftergastrointestinal in vitro digestion simulation for this ex-periment For ABTS+bull it was found an average of 14mmolTrolox kgminus 1 of total fraction and a var of simminus 85 ForDPPHbull values showed an average of 04mmol Trolox kgminus 1

for total fraction with a var of simminus 95 With respect toFRAP assay total fraction showed an average of 131mmolTrolox kgminus 1 and a var of simminus 93 Finally average TPC was099 g GAE kgminus 1 and TPC had a var of simminus 83

Although no statistical differences between irrigationtreatments were found on RF some assays showed highervalues than control such as DPPHbull (sim04mmol Trolox kgminus 1)and TPC (sim03 g GAE kgminus 1) -ose values could be relevant

because they might indicate that there are still antioxidantand polyphenolic compounds that could be metabolized bythe colon microflora and thus it points to a potential in-crease in bioavailability -erefore RF values found on tableolives coming from deficit irrigation strategies indicated thatstress caused on plant could affect the final bioavailability ofantioxidants and polyphenols increasing the content of thesecompounds available for human absorption [15]

Figure 1 represents the percentage of bioaccessibility ofTPC after the gastrointestinal in vitro digestion simulationIn both experiments no statistically significant differenceswere found among irrigation treatments In experiment AA0 presented 115 A1 111 A2 121 and A3 131 ofTPC bioaccessibility In experiment B control (B0) was

Table 2 Antioxidant activity (ABTS+bull DPPH and FRAP) and Total Phenolic Content (TPC) of ldquoManzanillardquo table olives before and aftergastrointestinal in vitro simulation digestion of experiment A and experiment B

Antioxidant activity (mmol trolox eq kg-1)TPC (g GAE kg-1)

ABTS+bull DPPHbull FRAPTM SF RF Total var TM SF RF Total var TM SF RF Total var TM SF RF Total var

Experiment AANOVAdagger NS lowastlowast NS lowast NS lowastlowastlowast NS lowast NS NS NS NS NS lowastlowast NS NS

A0 661 134bDagger 011 145

b minus 781 121 051ab 008 059

ab minus 951 154 106 020 125 minus 919 617 070b 042 113 minus 817

A1 748 156ab 013 169

ab minus 774 130 060a 026 087

a minus 933 160 075 022 097 minus 939 646 072a 033 105 minus 837

A2 707 143ab 011 153

b minus 784 125 037bc 009 047

ab minus 962 148 089 023 112 minus 924 590 072a 028 099 minus 832

A3 719 171a 025 198

a minus 725 112 025c 000 019

b minus 983 155 095 022 117 minus 925 547 072a 030 102 minus 814

Experiment BANOVA NS NS NS NS lowast NS NS NS lowastlowast NS NS NS lowastlowast NS NS NS

B0 874 123 005 129 minus 852 731c 047 000 047 minus 936 191

a 099 022 121 minus 937 546c 072 023 095 minus 826

B1 941 154 007 162 minus 828 964a 034 000 034 minus 965 178

b 112 024 136 minus 924 590a 072 034 105 minus 822

B2 934 126 006 132 minus 859 862b 031 000 031 minus 964 193

a 112 024 136 minus 930 583b 072 024 096 minus 835

daggerNSnot significant at plt 005 lowast lowastlowast and lowastlowastlowastsignificant at plt 005 001 and 0001 respectively DaggerValues followed by the same letter within the same columnwere not significantly different (plt 005) according to Tukeyrsquos least significant difference test Note TM test matrix SF soluble fraction liquid RF residualfraction solid Total SF +RF var ( variation) percentage of variation between the initial values and the values obtained after digestion

0

2

4

6

8

10

12

14

A0 A1 A2 A3

B

ioac

cess

ibili

ty

Experiment A

(a)

B0 B1 B20

2

4

6

8

10

12

14

B

ioac

cess

ibili

ty

Experiment B

(b)

Figure 1 Total phenol content bioaccessibility after gastrointestinal in vitro digestion simulation of ldquoManzanillardquo table olives of experimentA (a) ( ) and experiment B (b) ( ) Columns followed by the same letter within the same experiment were not significantly different(plt 005) according to Tukeyrsquos least significant difference test

4 Journal of Food Quality

132 bioaccessible while B1 and B2 treatments showed122 and 123 of TPC bioaccessibility respectively

-e decrease on antioxidant capacity and phenoliccompounds content may be related to their degradation Ahigh proportion of table olive polyphenols are very sus-ceptible to chemical degradation when they are submitted tothe acidic conditions of digestion [15] It was formerlydescribed the polyphenolic profile of hydroSOStainable tableolives of the current research [3] and it was found an in-crease of oleuropein comselogoside and verbascoside on A1treatment as compared with control as well as an increase ofelenoic acid glucoside oleuropein and comselogoside re-garding RDI treatments of experiment B Beside this in-creases it was previously reported that only 25 ofoleuropein (one of the most important polyphenols in tableolives) was stable during digestion as well as only 20 ofcomselogoside and elenoic acid derivatives [15] Flavonoidsverbascoside and hydroxytyrosol derivatives also presenteda small TPC bioaccessibility in a research conducted withthree table olives cultivars [14] Flavonoids are not verysoluble in either organic or aqueous solvents and are usuallypresent in foods in combination with sugars in the form ofglycosides [16] so it is possible that higher concentrationsthat were found on RDI table olives on some flavonoids suchas luteolin [3] would probably not have been extracted fromthe olive pulp during the in vitro digestion simulation

Similar results to the ones reported in the current studyhave been previously reported in ldquoCornezuelordquo table olives[15] For instance it was found a high decrease of DPPHbull

and ABTS+bull after gastrointestinal digestion simulation andalso a decrease of 75 of TPC

Several factors can influence the phenolic bioaccessibility-e digestion process could produce changes on polyphenolcomposition modifying their original profile -e food matrixwhere polyphenols are found could also influence the extraction[16] It has been previously reported that the fermentationprocess suffered during table olives preparation and the olivecultivar could influence the final polyphenol extraction [14]

-ere is lack of information about the how the stresssuffered by plants is related to the later metabolism of thecompounds by human digestive apparatus In the presentresearch the water stress suffered by olive trees due to ir-rigation strategies did not provide significant differencesamong treatments on final TPC and bioaccessibility in bothexperiments It has been demonstrated that it is possible tosave irrigation water without having significant effect on thefinal polyphenolic compounds available for human ab-sorption Daily intake of polyphenolic compounds is veryimportant because of their associated health benefits Highertotal consumption of 600mg per day would provide aprotective effect against chronic diseases [17] Consequentlyeating 10 hydroSOStainable table olives per day (40mg ofbioaccessible polyphenols) would contribute to a sim7 of thistotal polyphenol intake recommendation

4 Conclusions

-is is the first study investigating the effect of gastroin-testinal in vitro digestion simulation on antioxidant

potential and total polyphenol content and its bio-accessibility of table olives submitted to regulated deficitirrigation strategies Water stress was applied during twogrowing stages experiment A the pit hardening stage andexperiment B during the rehydration phase Results showedthat in experiment B antioxidants and polyphenols werenot affected by the stress after gastrointestinal in vitro di-gestion simulation while in experiment A regarding TPCABTS+bull and DPPHbull slight differences were found amongtreatments In general a total of sim1 g GAE kgminus 1 was extractedafter digestion indicating that the bioaccessibility of the TPCof both control and hydroSOStainable table olives was sim12-erefore the daily intake of 10 hydroSOStainable tableolives entails the intake of 40mg of ldquobioaccessiblerdquo poly-phenols and involve the daily of sim7 of polyphenols intakerecommendation for protective effect against chronicdiseases

Data Availability

-e data used to support the findings of this study are in-cluded within the article

Conflicts of Interest

-e authors declare that they have no conflicts of interest

Acknowledgments

-is study has been funded by (Ministerio de CienciaInnovacion (MCI) Agencia Estatal de Investigacion (AEI)and Fondo Europeo de Desarrollo Regional (FEDER))through a coordinated research project (hydroSOS mark)including the Universidad Miguel Hernandez de Elche(AGL2016-75794-C4-1-R hydroSOS foods) and the Uni-versidad de Sevilla (AGL2016-75794-C4-4-R) (MCIAEIFEDER UE) AuthorMarina Cano-Lamadrid was funded bya FPU grant from the Spanish Ministry of Education(FPU1502158)

References

[1] C Dinnella P Minichino A M DrsquoAndrea andE Monteleone ldquoBioaccessibility and antioxidant activitystability of phenolic compounds from extra-virgin olive oilsduring in vitro digestionrdquo Journal of Agricultural and FoodChemistry vol 55 no 21 pp 8423ndash8429 2007

[2] I DrsquoAntuono A Garbetta B Ciasca et al ldquoBiophenols fromtable olive cv bella di Cerignola chemical characterizationbioaccessibility and intestinal absorptionrdquo Journal of Agri-cultural and Food Chemistry vol 64 no 28 pp 5671ndash56782016

[3] L Sanchez-Rodrıguez M Cano-Lamadrid A A- Carbonell-Barrachina A Wojdyło E Sendra and F HernandezldquoPolyphenol profile in manzanilla table olives as affected bywater deficit during specific phenological stages and Spanish-style processingrdquo Journal of Agricultural and Food Chemistryvol 67 no 2 pp 661ndash670 2019

[4] M H Ahmad-Qasem J Canovas E Barrajon-CatalanJ E Carreres V Micol and J V Garcıa-Perez ldquoInfluence ofolive leaf processing on the bioaccessibility of bioactive

Journal of Food Quality 5

polyphenolsrdquo Journal of Agricultural and Food Chemistryvol 62 no 26 pp 6190ndash6198 2014

[5] M J Martın-Palomo M Corell I Giron et al ldquoAbsence ofyield reduction after controlled water stress during prehaverstperiod in table olive treesrdquo Agronomy vol 10 no 2 p 2582020

[6] B J Myers ldquoWater stress integral-a link between short-termstress and long-term growthrdquo Tree Physiology vol 4 no 4pp 315ndash323 1988

[7] L Sanchez-Rodrıguez L Lipan L Andreu et al ldquoEffect ofregulated deficit irrigation on the quality of raw and tableolivesrdquo Agricultural Water Management vol 221 pp 415ndash421 2019

[8] M Minekus M Alminger P Alvito et al ldquoA standardisedstaticin vitrodigestion method suitable for foodmdashan inter-national consensusrdquo Food and Function vol 5 no 6pp 1113ndash1124 2014

[9] M Cano-Lamadrid F Hernandez M Corell et al ldquoAnti-oxidant capacity fatty acids profile and descriptive sensoryanalysis of table olives as affected by deficit irrigationrdquo Journalof the Science of Food and Agriculture vol 97 no 2pp 444ndash451 2017

[10] R Re N Pellegrini A Proteggente A Pannala M Yang andC Rice-Evans ldquoAntioxidant activity applying an improvedABTS radical cation decolorization assayrdquo Free Radical Bi-ology and Medicine vol 26 no 9-10 pp 1231ndash1237 1999

[11] W Brand-Williams M E Cuvelier and C Berset ldquoUse of afree radical method to evaluate antioxidant activityrdquoLWTmdashFood Science and Technology vol 28 no 1 pp 25ndash301995

[12] I F F Benzie and J J Strain ldquo-e ferric reducing ability ofplasma (FRAP) as a measure of ldquoantioxidant powerrdquo theFRAP assayrdquo Analytical Biochemistry vol 239 no 1pp 70ndash76 1996

[13] X GaoM Ohlander N Jeppsson L Bjork and V TrajkovskildquoChanges in antioxidant effects and their relationship tophytonutrients in fruits of sea buckthorn (Hippophae rham-noides L) during maturationrdquo Journal of Agricultural andFood Chemistry vol 48 no 5 pp 1485ndash1490 2000

[14] I DrsquoAntuono A Bruno V Linsalata et al ldquoFermentedApulian table olives effect of selected microbial starters onpolyphenols composition antioxidant activities and bio-accessibilityrdquo Food Chemistry vol 248 pp 137ndash145 2018

[15] M P Fernandez-Poyatos A Ruiz-Medina and E J Llorent-Martınez ldquoPhytochemical profile mineral content and an-tioxidant activity of Olea europaea L Cv Cornezuelo tableolives Influence of in vitro simulated gastrointestinal diges-tionrdquo Food Chemistry vol 297 Article ID 124933 2019

[16] F A Tomas-Barberan ldquoLos polifenoles de los alimentos y lasaludrdquo Alimentacion Nutricion Y Salud vol 10 no 2pp 41ndash53 2006

[17] I Navarro Gonzalez M J Periago and F J Garcıa AlonsoldquoEstimacion de la ingesta diaria de compuestos fenolicos en lapoblacion espantildeolardquo Revista Espantildeola de Nutricion HumanaY Dietetica vol 21 no 4 pp 320ndash326 2017

6 Journal of Food Quality

132 bioaccessible while B1 and B2 treatments showed122 and 123 of TPC bioaccessibility respectively

-e decrease on antioxidant capacity and phenoliccompounds content may be related to their degradation Ahigh proportion of table olive polyphenols are very sus-ceptible to chemical degradation when they are submitted tothe acidic conditions of digestion [15] It was formerlydescribed the polyphenolic profile of hydroSOStainable tableolives of the current research [3] and it was found an in-crease of oleuropein comselogoside and verbascoside on A1treatment as compared with control as well as an increase ofelenoic acid glucoside oleuropein and comselogoside re-garding RDI treatments of experiment B Beside this in-creases it was previously reported that only 25 ofoleuropein (one of the most important polyphenols in tableolives) was stable during digestion as well as only 20 ofcomselogoside and elenoic acid derivatives [15] Flavonoidsverbascoside and hydroxytyrosol derivatives also presenteda small TPC bioaccessibility in a research conducted withthree table olives cultivars [14] Flavonoids are not verysoluble in either organic or aqueous solvents and are usuallypresent in foods in combination with sugars in the form ofglycosides [16] so it is possible that higher concentrationsthat were found on RDI table olives on some flavonoids suchas luteolin [3] would probably not have been extracted fromthe olive pulp during the in vitro digestion simulation

Similar results to the ones reported in the current studyhave been previously reported in ldquoCornezuelordquo table olives[15] For instance it was found a high decrease of DPPHbull

and ABTS+bull after gastrointestinal digestion simulation andalso a decrease of 75 of TPC

Several factors can influence the phenolic bioaccessibility-e digestion process could produce changes on polyphenolcomposition modifying their original profile -e food matrixwhere polyphenols are found could also influence the extraction[16] It has been previously reported that the fermentationprocess suffered during table olives preparation and the olivecultivar could influence the final polyphenol extraction [14]

-ere is lack of information about the how the stresssuffered by plants is related to the later metabolism of thecompounds by human digestive apparatus In the presentresearch the water stress suffered by olive trees due to ir-rigation strategies did not provide significant differencesamong treatments on final TPC and bioaccessibility in bothexperiments It has been demonstrated that it is possible tosave irrigation water without having significant effect on thefinal polyphenolic compounds available for human ab-sorption Daily intake of polyphenolic compounds is veryimportant because of their associated health benefits Highertotal consumption of 600mg per day would provide aprotective effect against chronic diseases [17] Consequentlyeating 10 hydroSOStainable table olives per day (40mg ofbioaccessible polyphenols) would contribute to a sim7 of thistotal polyphenol intake recommendation

4 Conclusions

-is is the first study investigating the effect of gastroin-testinal in vitro digestion simulation on antioxidant

potential and total polyphenol content and its bio-accessibility of table olives submitted to regulated deficitirrigation strategies Water stress was applied during twogrowing stages experiment A the pit hardening stage andexperiment B during the rehydration phase Results showedthat in experiment B antioxidants and polyphenols werenot affected by the stress after gastrointestinal in vitro di-gestion simulation while in experiment A regarding TPCABTS+bull and DPPHbull slight differences were found amongtreatments In general a total of sim1 g GAE kgminus 1 was extractedafter digestion indicating that the bioaccessibility of the TPCof both control and hydroSOStainable table olives was sim12-erefore the daily intake of 10 hydroSOStainable tableolives entails the intake of 40mg of ldquobioaccessiblerdquo poly-phenols and involve the daily of sim7 of polyphenols intakerecommendation for protective effect against chronicdiseases

Data Availability

-e data used to support the findings of this study are in-cluded within the article

Conflicts of Interest

-e authors declare that they have no conflicts of interest

Acknowledgments

-is study has been funded by (Ministerio de CienciaInnovacion (MCI) Agencia Estatal de Investigacion (AEI)and Fondo Europeo de Desarrollo Regional (FEDER))through a coordinated research project (hydroSOS mark)including the Universidad Miguel Hernandez de Elche(AGL2016-75794-C4-1-R hydroSOS foods) and the Uni-versidad de Sevilla (AGL2016-75794-C4-4-R) (MCIAEIFEDER UE) AuthorMarina Cano-Lamadrid was funded bya FPU grant from the Spanish Ministry of Education(FPU1502158)

References

[1] C Dinnella P Minichino A M DrsquoAndrea andE Monteleone ldquoBioaccessibility and antioxidant activitystability of phenolic compounds from extra-virgin olive oilsduring in vitro digestionrdquo Journal of Agricultural and FoodChemistry vol 55 no 21 pp 8423ndash8429 2007

[2] I DrsquoAntuono A Garbetta B Ciasca et al ldquoBiophenols fromtable olive cv bella di Cerignola chemical characterizationbioaccessibility and intestinal absorptionrdquo Journal of Agri-cultural and Food Chemistry vol 64 no 28 pp 5671ndash56782016

[3] L Sanchez-Rodrıguez M Cano-Lamadrid A A- Carbonell-Barrachina A Wojdyło E Sendra and F HernandezldquoPolyphenol profile in manzanilla table olives as affected bywater deficit during specific phenological stages and Spanish-style processingrdquo Journal of Agricultural and Food Chemistryvol 67 no 2 pp 661ndash670 2019

[4] M H Ahmad-Qasem J Canovas E Barrajon-CatalanJ E Carreres V Micol and J V Garcıa-Perez ldquoInfluence ofolive leaf processing on the bioaccessibility of bioactive

Journal of Food Quality 5

polyphenolsrdquo Journal of Agricultural and Food Chemistryvol 62 no 26 pp 6190ndash6198 2014

[5] M J Martın-Palomo M Corell I Giron et al ldquoAbsence ofyield reduction after controlled water stress during prehaverstperiod in table olive treesrdquo Agronomy vol 10 no 2 p 2582020

[6] B J Myers ldquoWater stress integral-a link between short-termstress and long-term growthrdquo Tree Physiology vol 4 no 4pp 315ndash323 1988

[7] L Sanchez-Rodrıguez L Lipan L Andreu et al ldquoEffect ofregulated deficit irrigation on the quality of raw and tableolivesrdquo Agricultural Water Management vol 221 pp 415ndash421 2019

[8] M Minekus M Alminger P Alvito et al ldquoA standardisedstaticin vitrodigestion method suitable for foodmdashan inter-national consensusrdquo Food and Function vol 5 no 6pp 1113ndash1124 2014

[9] M Cano-Lamadrid F Hernandez M Corell et al ldquoAnti-oxidant capacity fatty acids profile and descriptive sensoryanalysis of table olives as affected by deficit irrigationrdquo Journalof the Science of Food and Agriculture vol 97 no 2pp 444ndash451 2017

[10] R Re N Pellegrini A Proteggente A Pannala M Yang andC Rice-Evans ldquoAntioxidant activity applying an improvedABTS radical cation decolorization assayrdquo Free Radical Bi-ology and Medicine vol 26 no 9-10 pp 1231ndash1237 1999

[11] W Brand-Williams M E Cuvelier and C Berset ldquoUse of afree radical method to evaluate antioxidant activityrdquoLWTmdashFood Science and Technology vol 28 no 1 pp 25ndash301995

[12] I F F Benzie and J J Strain ldquo-e ferric reducing ability ofplasma (FRAP) as a measure of ldquoantioxidant powerrdquo theFRAP assayrdquo Analytical Biochemistry vol 239 no 1pp 70ndash76 1996

[13] X GaoM Ohlander N Jeppsson L Bjork and V TrajkovskildquoChanges in antioxidant effects and their relationship tophytonutrients in fruits of sea buckthorn (Hippophae rham-noides L) during maturationrdquo Journal of Agricultural andFood Chemistry vol 48 no 5 pp 1485ndash1490 2000

[14] I DrsquoAntuono A Bruno V Linsalata et al ldquoFermentedApulian table olives effect of selected microbial starters onpolyphenols composition antioxidant activities and bio-accessibilityrdquo Food Chemistry vol 248 pp 137ndash145 2018

[15] M P Fernandez-Poyatos A Ruiz-Medina and E J Llorent-Martınez ldquoPhytochemical profile mineral content and an-tioxidant activity of Olea europaea L Cv Cornezuelo tableolives Influence of in vitro simulated gastrointestinal diges-tionrdquo Food Chemistry vol 297 Article ID 124933 2019

[16] F A Tomas-Barberan ldquoLos polifenoles de los alimentos y lasaludrdquo Alimentacion Nutricion Y Salud vol 10 no 2pp 41ndash53 2006

[17] I Navarro Gonzalez M J Periago and F J Garcıa AlonsoldquoEstimacion de la ingesta diaria de compuestos fenolicos en lapoblacion espantildeolardquo Revista Espantildeola de Nutricion HumanaY Dietetica vol 21 no 4 pp 320ndash326 2017

6 Journal of Food Quality

polyphenolsrdquo Journal of Agricultural and Food Chemistryvol 62 no 26 pp 6190ndash6198 2014

[5] M J Martın-Palomo M Corell I Giron et al ldquoAbsence ofyield reduction after controlled water stress during prehaverstperiod in table olive treesrdquo Agronomy vol 10 no 2 p 2582020

[6] B J Myers ldquoWater stress integral-a link between short-termstress and long-term growthrdquo Tree Physiology vol 4 no 4pp 315ndash323 1988

[7] L Sanchez-Rodrıguez L Lipan L Andreu et al ldquoEffect ofregulated deficit irrigation on the quality of raw and tableolivesrdquo Agricultural Water Management vol 221 pp 415ndash421 2019

[8] M Minekus M Alminger P Alvito et al ldquoA standardisedstaticin vitrodigestion method suitable for foodmdashan inter-national consensusrdquo Food and Function vol 5 no 6pp 1113ndash1124 2014

[9] M Cano-Lamadrid F Hernandez M Corell et al ldquoAnti-oxidant capacity fatty acids profile and descriptive sensoryanalysis of table olives as affected by deficit irrigationrdquo Journalof the Science of Food and Agriculture vol 97 no 2pp 444ndash451 2017

[10] R Re N Pellegrini A Proteggente A Pannala M Yang andC Rice-Evans ldquoAntioxidant activity applying an improvedABTS radical cation decolorization assayrdquo Free Radical Bi-ology and Medicine vol 26 no 9-10 pp 1231ndash1237 1999

[11] W Brand-Williams M E Cuvelier and C Berset ldquoUse of afree radical method to evaluate antioxidant activityrdquoLWTmdashFood Science and Technology vol 28 no 1 pp 25ndash301995

[12] I F F Benzie and J J Strain ldquo-e ferric reducing ability ofplasma (FRAP) as a measure of ldquoantioxidant powerrdquo theFRAP assayrdquo Analytical Biochemistry vol 239 no 1pp 70ndash76 1996

[13] X GaoM Ohlander N Jeppsson L Bjork and V TrajkovskildquoChanges in antioxidant effects and their relationship tophytonutrients in fruits of sea buckthorn (Hippophae rham-noides L) during maturationrdquo Journal of Agricultural andFood Chemistry vol 48 no 5 pp 1485ndash1490 2000

[14] I DrsquoAntuono A Bruno V Linsalata et al ldquoFermentedApulian table olives effect of selected microbial starters onpolyphenols composition antioxidant activities and bio-accessibilityrdquo Food Chemistry vol 248 pp 137ndash145 2018

[15] M P Fernandez-Poyatos A Ruiz-Medina and E J Llorent-Martınez ldquoPhytochemical profile mineral content and an-tioxidant activity of Olea europaea L Cv Cornezuelo tableolives Influence of in vitro simulated gastrointestinal diges-tionrdquo Food Chemistry vol 297 Article ID 124933 2019

[16] F A Tomas-Barberan ldquoLos polifenoles de los alimentos y lasaludrdquo Alimentacion Nutricion Y Salud vol 10 no 2pp 41ndash53 2006

[17] I Navarro Gonzalez M J Periago and F J Garcıa AlonsoldquoEstimacion de la ingesta diaria de compuestos fenolicos en lapoblacion espantildeolardquo Revista Espantildeola de Nutricion HumanaY Dietetica vol 21 no 4 pp 320ndash326 2017

6 Journal of Food Quality