Journal of Food Quality Thermal Degradation of Plum …downloads.hindawi.com/journals/jfq/2018/1598756.pdf · 2019-07-30 · Research Article Journal of Food Quality Thermal Degradation

Research ArticleJournal of Food Quality Thermal Degradation of PlumAnthocyanins Comparison of Kinetics from Simple toNatural Systems

Mihaela Turturica1 Nicoleta Stanciuc1 Claudia Muresan2 Gabriela Rapeanu 1

and Constantin Croitoru 3

1Faculty of Food Science and Engineering Dunarea de Jos University of Galati 111 Domneasca Street 800201 Galati Romania2Faculty of Food Engineering Tourism and Environmental Protection Aurel Vlaicu University of Arad 2 Elena Dragoi Street310330 Arad Romania3Academy of Agricultural and Forestry Sciences 61 Marasti Blvd 011464 Bucharest Romania

Correspondence should be addressed to Constantin Croitoru ccroitorusodinalcom

Received 5 April 2018 Revised 18 May 2018 Accepted 28 May 2018 Published 21 June 2018

Academic Editor Angel A Carbonell-Barrachina

Copyright copy 2018Mihaela Turturica et alis is an open access article distributed under theCreativeCommonsAttribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

e stability of anthocyanin was assessed over a temperature range of 50ndash120degC in dierent simulated plum juices in order tocompare the thermal behavior in the presence of certain compounds e results were correlated with the antioxidant activity andintrinsic uorescence spectra e results suggested signicant changes especially at higher temperature hence increase in theuorescence intensity and some bathochromic and hypsochromic shifts were observed Anthocyanins in natural matrices presentedthe highest rate for degradation followed by the anthocyanins in juices with sugars Values of the activation energies were 4240plusmn687 kJmol for the degradation in water 4070plusmn 425 kJmol for the juices with citric acid 2303plusmn 353 kJmol for the juicescontaining sugars 3599plusmn 360 kJmol for simulated juices withmixture and 1419plusmn 239 kJmol for natural juices A protective eectof sugars was evidenced whereas in natural matrices the degradation rate constant showed lower temperature dependence

1 Introduction

Fruit-based foods have turned into very popular goods becauseconsumers associate them to healthy products so theircommercialization has increased in the last years [1] Amongthem fruits like red plums are one of the most importantbecause they are consumed directly or are used as a rawmaterial for juices puree jellies compote and jams Besidesother sensorial parameters the color is one of main qualityparameter which inuences the consumersrsquo preference andbehavior e attractive red color of plums is associated withthe presence of anthocyanins Many studies demonstrated thatanthocyanins have potential health benets for humans as theypossess anticarcinogenic properties [2] prevent cardiovasculardiseases like atherosclerosis [3] have antidiabetic properties[4] and protect against Alzheimerrsquos disease [5] Additionallythe special interest in anthocyanins is early recognized if as

natural food colorants especially if suitable puried and stablematerial becomes commercially available [6]

Anthocyanins are glycosides of polyhydroxy and poly-methoxy derivatives of 2-phenylbenzopyrylium or aviliumsalts Glycosylation and acylation of the aglycone moieties(mainly six anthocyanidins pelargonidin cyanidin peonidindelphinidin petunidin and malvidin) by dierent sugars andacids at dierent positions account for the broad structuraldiversity of these pigments [7]emain anthocyanins presentin red plums are 3-O bound glucose of cyanidin and peonidinand 3-O bound rutin of cyanidin and peonidin [8] Howeverthe total content of the anthocyanins in red plums are aectedby the cultivarmaturity level year of production and dierentenvironmental factors [9]

erefore one of themain challenges in red plum productprocessing is the preservation of anthocyanins which is animportant issue because anthocyanins are highly unstable and

HindawiJournal of Food QualityVolume 2018 Article ID 1598756 10 pageshttpsdoiorg10115520181598756

are susceptible to degradation [10] (e stability of the an-thocyanins depends on several factors such as pH temper-ature oxygen metallic ions ascorbic acid sugars and theirdegradation products [11] It has been reported that antho-cyanins exhibit higher stability under acidic conditions butunder normal processing and storage conditions readilyconvert to colorless derivatives and subsequently to insolublebrown pigments [7](e red plum juice color is influenced bythermal treatment used to preserve and to extend the shelf lifeof juices During thermal treatment the anthocyanins de-grade due to their high reactivity and also they may poly-merize which is related to degradation of color and loss ofnutritional values in food products [12] Several studies wereperformed in order to evaluate the stability of anthocyaninsthrough addition of sugars acids hydrocolloids salts anddifferent phenolic compounds in various fruit productsduring thermal treatment [12ndash15] By studying the data fromthe literature it can be assumed that the thermal degradationof anthocyanins depends onmatrices fromwhich it originatesand the complexity of the heating environment It is clear thatthe raw materialsrsquo variability and the different heating con-ditions are hardly comparable in terms of temperature andtime solid content or the presence of extraction solvent [16](ere is a need to relate the kinetics of thermal degradation ofanthocyanins concomitant to increase the complexity of thesystem (erefore the main objective was the evaluation ofthermal degradation of anthocyanins from plums in mediumwith increased complexity during heating at a temperaturerange between 50 and 120degC on a kinetic basis (e HPLCtechnique was employed to evaluate the degradation of in-dividual anthocyanins identified in plum juices at tempera-tures of 25degC and 100degC after 20minutes of holding Since redplum juices are a good source of antioxidants the change inantioxidant capacity during thermal treatment was also in-vestigated Intrinsic fluorescence spectroscopy technique wasused as an additional technique to extend the possibilities ofanalysis of the heat-induced changes in anthocyanins

2 Materials and Methods

21 Chemicals 22-Diphenyl-1-picrylhydrazyl (DPPH) 6-Hydroxy-2578-tetramethylchromane-2-carboxylic acid (Tro-lox) sodiumacetate potassium chloride ethanol andmethanol(HPLC grade) were obtained from Sigma Aldrich SteinheimGermany Cyanidin and pelargonidin standards were obtainedfrom Extrasynthese (ZI Lyon Nord France)

22 Juices Preparation Plums (Prunus domestica Vanettevariety) were provided from the local market (Galati county)during JunendashJuly 2015 Fruits samples were washed withwater in the ratio of 1 2 (ww) After washing the skins weremanually separated and then were washed with distilledwater Finally they were blotted on paper towels to removeany residual pulp (e extraction of anthocyanins fromfreeze-dried red plums was performed according to a pre-viously described procedure [8]

Plum juices were obtained as following

(i) PW (plum juice in water) was obtained from theconcentrated plum extract (lyophilized plum skins

70 ethanol ratio of 1 8) which was then dissolvedin 20mL distilled water

(ii) PCA (plum juice with citric acid) was obtained inthe same way as PW the difference being the ad-dition of citric acid (2213 g citric acidL extract)

(iii) PS (plum juice with sugars) was obtained in the sameway as PW with the addition of glucose and fructose(244 g glucoseL extract and 6197 g fructoseL extract)

(iv) PM (plum juice with mixture) represents the juiceobtained with the addition of all the above men-tioned compounds in the same ratio

(v) PN (natural plum juice) was obtained from 250 gplums that were crushed and afterwards 1 g ofZymorouge enzyme was added and left for 24 h inorder to achieve the extraction of the pigments (eobtained juice was then filtered using a cheese cloth

23 Heat Treatment A volume of 200 microL of juices was filledin Eppendorf tubes (1 cm diameter) and heated at tempera-tures ranging from 50 to 120degC for 30min for the fluorescencespectroscopy experiments (e same temperature range from50degC to 120deg but different times (0ndash60min) were used forthermal treatment in the case of thermal degradation kineticstudies

Heating experiments were conducted in a thermostaticoil bath (Nahita 6023 Navarra Spain) according to a pre-viously described procedure [8]

24 HPLC Analysis of Anthocyanins (e identification andquantification of plum juice anthocyanins were made usinga (ermo Finnigan Surveyor HPLC system controlled byXcalibur software system (Finnigan Surveyor LC (ermoScientific USA) (e column used for the separation ofplum anthocyanins was Synergi 4u Fusion-RP 80A(150mmtimes 46mm 4 μm)(e column was operated at 25degCat a wavelength of 520 nm (e elution profile was ac-complished with 100 methanol (A) and 10 formic acid(B) (e elution program employed was 0ndash20min 9ndash35(A) 20ndash30min 35 (A) 30ndash40min 35ndash50 (A) and40ndash55min 50ndash9 (A) (e injection amount was 10 μL ata flow rate of 1mLmin

25 Phytochemicals Analysis Total monomeric anthocya-nins (TAC) and free radical scavenging activity (DPPHRSA)of juices were estimated according to our earlier report [8]

26 Fluorescence Spectroscopy Measurements Fluorescencemeasurements were carried out using a LS-55 luminescencespectrometer (PerkinElmer Life Sciences Shelton CT USA)as described earlier by Turturica [8]

27 Mathematical Models and Kinetic Analysis (e degra-dation kinetics of TAC in PW PCA PS and PM weredescribed by fitting the first order kinetic model (1) to ex-perimental data

2 Journal of Food Quality

C

C0 eminuskt

(1)

where C is the parameter to be estimated the subscript 0indicates the initial value of the parameter t is the heatingtime and k is the rate constant at temperature T (1min)

(e degradation kinetic of TAC in PN was described byfitting a first-order fractional conversion kinetic model Inthis model the changes in TAC (C) as a function of heatingtime are described by (2)

Ct Cinfin + Ci minusCinfin( 1113857exp(minuskt) (2)

with Cinfin the equilibrium value at infinite heating time (thevalue after which longer heating time does not result inchanges in C value) and Ci is the TAC values of the samplesat time 0 of thermal treatment

(e half-life (t12) of the reaction was calculated as-suming the first-order kinetics according to (3)

t12 minusln 05

k (3)

(e Arrhenius model was used to describe the tem-perature dependence of degradation rate constants

28 Statistical Analysis of Data All experiments were per-formed in triplicates with duplicate samples (e resultswere expressed in terms of average values Statistical analysisof data was performed using the data analysis tool pack ofthe Microsoft Excel software (e coefficient of determi-nation (R2) and mean square error (MSE) were used ascriteria for adequacy of fit

3 Results and Discussion

31 HPLC Analysis of Anthocyanins from JuicesChromatographic analysis of the plum juices performed at520nm pointed out the presence of four peaks correspondingto cyanidin 3-xylosidecyanidin 3-glucoside (peak 1) cyanidin3-rutinoside (peak 2) peonidin 3-glucoside (peak 3) andpeonidin 3-rutinoside (peak 4) (Figure 1)

(e content of each anthocyanin at different tempera-tures corresponding to each juice is presented in Table 1

As it can be seen from Table 1 in all plum juices thepredominant anthocyanin was C3R (ermal treatment at100degC for 20 minutes caused a decrease in anthocyaninscontent In PW the anthocyanin concentration decreaseswith about 22ndash25 while in the PCA C3G decreases withabout 17 compared to the other three anthocyanins whichdegrades with approximately 45 Interesting is the increasein C3G content by approximately 8 in PS by heating at100degC while the other two compounds concentration de-creases with 19ndash21 A significant increase in C3G and P3Gconcentration of approximately 44 and 162 respectivelyoccurred in PM while C3R and P3R concentration de-creased with 572 and 433 respectively It can be ap-preciated that the mixture between citric acid glucose andfructose had the most protective effect on anthocyaninsthermal degradation

Only three anthocyanins could be quantified in PN afterheating at 100degC namely cyanidin 3-xylosidecyanidin 3-glucoside (peak 1) cyanidin 3-rutinoside (peak 2) and peo-nidin 3-rutinoside (peak 4) whereas peonidin 3-glucoside(peak 3) was entirely degraded Significant degradation ofcyanidin 3-xylosidecyanidin 3-glucoside (9167 peak 1)cyanidin 3-rutinoside (9652 peak 2) andpeonidin 3-rutinoside(9122 peak 4) was found in PN

32 4e Influence of 4ermal Treatment on TAC and DPPHRSA of Plum Juices Total anthocyanin content of untreatedPW PCA PS PM and PN was 144 52 53 51 and 38mgLrespectively Heating the PCA at temperature ranging from 50to 90degC for up to 45min caused an increase in TAC (isphenomenon was explained by Hubbermann [14] by thepresence of an equilibrium between the four anthocyaninchromophores in aqueous solutions Heating of juices pre-sented a significant impact on anthocyanin content witha decrease of 85 53 61 50 and 86 respectively after60min of treatment at temperature of 120degC It can be noticedthat the presence of citric acid sugar and their combinationhad a stabilizing effect on anthocyanins thermal degradationin accordance with previously reported results [10 14] (estability of anthocyanins is influenced by temperature pHchemical structure of the anthocyanin compound UV lightoxygen oxidative and hydrolytic enzymes proteins and themetallic ions [17] In food industry the citric acid is used as anacidifier and antioxidant to control the browning process[18 19] According to Shaheer [20] the higher thermostabilityof anthocyanins in the presence of citric acid may be due todiacylation of structure that improves anthocyanin stability byprotecting it from hydration (ey also suggested that thepresence of inter- and intramolecular copigmentation withother moieties and polyglycosylated and polyacylated an-thocyanins provides greater stability towards change intemperature pH and light

An increase in anthocyanidin stability has been also re-ported by Francis [21] due to glycosylation and acylation Tothe best of our knowledge there are limited studies in theliterature presenting the presence of acylation for the an-thocyanins from plum For example Wu and Prior [22] re-ported the presence of cyanidin 3-(6Prime-acetoyl) glucoside andcyanidin 3-(maloyl) glucoside in plum and black plumHowever we suspected that PCA should contain acylatedanthocyanins to a certain extent because its anthocyaninsshowed higher stability than those from corresponding juicesHigher stability of plum anthocyanins could therefore beattributed to the presence of much higher amounts of acylatedanthocyanins Stabilization effect due to sugar additionmay becaused by lowering the water activity since water activity wasreported in literature to influence anthocyanin stability [23]

Szaloki-Dorko [24] suggested also a decrease of the an-thocyanin content of Erdi bőtermő juices from 812 to501mgL at 90degC after 240min of heating Degradation waslower at 80degC and the treatment for 4 h at this temperatureresulted in 29 loss of total anthocyanin content compared tothe original levels found in fresh juice Volden et al [25]reported that blanching boiling and steaming resulted in

Journal of Food Quality 3

ndash10000

90000

190000

290000

390000

490000

590000

10 15 20

Abs

orba

nce a

t 520

nm

(μA

U)

Time (min)

PW 25degCPW 100degC

2

3

(a)

Time (min)

PCA 25degCPCA 100degC

ndash10000

90000

190000

290000

390000

490000

590000

10 12 14 16 18 20

Abs

orba

nce a

t 520

nm

(μA

U)

(b)

ndash10000

90000

190000

290000

390000

490000

590000

10 12 14 16 18 20

Abs

orba

nce a

t 520

nm

(μA

U)

Time (min)

PS 25degCPS 100degC

(c)

ndash10000

90000

190000

290000

390000

490000

590000

690000

10 12 14 16 18 20

Abs

orba

nce a

t 520

nm

(μA

U)

Time (min)

PM 25degCPM 100degC

(d)

0

200000

400000

600000

800000

1000000

10 15 20

Abs

orba

nce a

t 520

nm

(μA

U)

Time (min)

PN 25degCPN 100degC

(e)

Figure 1 HPLC chromatogram of plum anthocyanins at 25degC and after 20 minutes of treatment at 100degC from (a) plum juice with water(PW) (b) plum juice with citric acid (PCA) (c) plum juice with sugars (PS) (d) plum juice with mixture (PM) and (e) natural plum juice(PN) at 520 nm For PW PCA PS and PM peaks represent (1) cyanidin 3-glucoside (2) cyanidin 3-rutinoside (3) peonidin 3-glucoside(4) peonidin 3-rutinoside Peak assignments are given in Table 1


Tabl

e1

Antho

cyaninscontentinPW

PCAP

SPM

and

PNexpressedas

μgg

at25

deg Candafter20

min

oftreatm

enta

t100degC

Juice

PWPC

APS

PMPN

Antho

cyanin

25deg C

100degC

25deg C

100degC

25deg C

100degC

25deg C

100degC

25deg C

100degC

C3G

3789plusmn287

2817plusmn178

3230plusmn125

2702plusmn178

2147plusmn199

2316plusmn154

2462plusmn141

3540plusmn124

8705plusmn152

725plusmn009

C3R

43461plusmn1154

33642plusmn1598

55955plusmn5221

30908plusmn1178

40336plusmn1432

31647plusmn1756

42107plusmn1627

39699plusmn501

52588plusmn314

1830plusmn187

P3G

00

093plusmn012

065plusmn010

00

158plusmn045

416plusmn101

1636plusmn048

0P3

R23678plusmn1454

18336plusmn1024

30071plusmn1124

16622plusmn236

21721plusmn1087

17465plusmn947

22487plusmn1147

21512plusmn1421

41554plusmn569

3648plusmn294

C3G

cyanidin3-xylosid

ecyanidin

3-glucosideC3R

cyanidin3-rutin

osideP3

Gp

eonidin3-glucosideP3

Rpeon

idin

3-rutin

oside


anthocyanin losses of 59 41 and 29 respectively in redcabbage ermal degradation of TAC includes the chalconeformation or loss of glycosyl moieties [26]

e antioxidant activities of the ve tested juices were6607 2500 3031 2634 and 5257 in PW PCA PS PMand PN respectively Heating caused an increase in DPPHRSA to 8314 3970 and 4502 respectively after 15minat 50degC e increase in DPPH RSA may be due to the an-thocyanin degradation in phloroglucinaldehyde and proto-catechic acid the latter having higher antioxidant activity[27] At higher temperature of heating the treatment induceda decrease in the concentrations of anthocyanins with neg-ative impact on antioxidant activity However at a highertemperature a decrease with 8 in PW and 9438 in PMwas registered after 60min at 120degC A protective eect offood matrices was observed in PN the reduction in DPPHRSA being of only 24

33 Kinetics ofermal Degradation Degradation kinetic ofTAC in PW PCA PS and PMwasmodeled using rst-orderkinetic model (2)(Figure 2) whereas the degradation ofanthocyanin in PN was tted to the fractional conversionkinetic model (3) (Figure 3)

e kinetic parameters of TAC degradation in dierentjuices while heating are displayed in Table 2 Considering thewide sample variability and that a single set of parameters isused at each temperature for all experiments the resultsshowed good correlation between experimental and corre-lated values (Figure 4)

e heat-induced changes in TAC were described interms of degradation rate (1min) and degradation energy ofactivation (Ea) In case of PW the degradation rate constant(k) increases from 018plusmn 001middot10minus21min at 50degC to 287plusmn047middot10minus21min at 120degC (Table 2) e degradation rate ofanthocyanins in PCA ranged from 004plusmn 001middot10minus21min at50degC to 117plusmn 011middot10minus21min at 120degC For PS the k was 366times higher at 120degC when compared with 50degC rangingfrom 036plusmn 001middot10minus21min to 154plusmn 012middot10minus21min sug-gesting a lower thermal stability of anthocyanin compoundsat higher temperature An increase in k values were observedalso in case of PM varying from 011plusmn 008middot10minus21min at 50degCto 117plusmn 025middot10minus21min at 120degC A higher degradation rate

ndash09ndash08ndash07ndash06ndash05ndash04ndash03ndash02ndash01

00 10 20 30 40 50 60

Ln (C

C0)

Heating time (min)

(a)

Ln (C

C0)

ndash039ndash034ndash029ndash024ndash019ndash014ndash009ndash004

001 0 10 20 30 40 50 60Heating time (min)

(b)

ndash05ndash045

ndash04ndash035

ndash03ndash025

ndash02ndash015

ndash01ndash005

00 10 20 30 40 50 60

Log

(CC

0)

Heating time (min)

(c)

Ln (C

C0)

ndash039ndash034

ndash024ndash029

ndash019ndash014ndash009ndash004

001 0 10 20 30 40 50 60Heating time (min)

(d)

Figure 2 Isothermal degradation of anthocyanin in PW (a) PCA (b) PS (c) and PM (d) as described by rst-order kinetic model atdierent temperatures ( 50degC 70degC 90degC 100degC 110degC and ∆ 120degC)

00005

0010015

0020025

0030035

004

0 10 20 30 40 50 60

C

Heating time (min)

Figure 3 Isothermal degradation of TAC in PN as described by thefractional conversion kinetic model (3) at dierent temperatures( 50degC 70degC 90degC 100degC and 110degC) e linesrepresent model ts to experimental data


of anthocyanins in PN with an increase of k values from821plusmn 349middot10minus21min at 50degC to 2092plusmn 050middot10minus21min at110degC can be observed (Table 2)

Wang andXu [28] suggested signicantly higher k values of394middot1031min for the anthocyanin degradation in blackberryjuice at 90degC Harbourne [29] reported k value of 1861min forthe degradation kinetic of anthocyanins in a blackcurrantmodel juice system at temperature of 100degC

e t12 values are expressed in (3) and presented inTable 2 e half-life at 50degC for PW PCA PS PM and PNwere 627plusmn 115h 2508plusmn 128 h 313plusmn 015h 1003plusmn 038and 014plusmn 0003h respectively A decrease in t12 was found

when the temperature increases given values of 040plusmn 002h098plusmn 015h 074plusmn 009 h 098plusmn 004 h and 005plusmn 0002h at120degC From Table 2 it can be seen that the highest decrease int12 was determined for PW and PCA being higher than thatfor the corresponding juices whereas the most protective eecthad glucose with a decrease of only 76 Harbourne [29]reported t12 values of 218plusmn 004h at 100degC for the degradationkinetics of anthocyanins in a blackcurrant model juice systemSignicantly higher values were found by Cemeroglu [30] forsour cherry juice of 5434 and 81 h at 60degC and 80degC whichindicates that sour cherries anthocyanins are more heat stablethan those in plum juices e thermal degradation of an-thocyanins in blood orange juice had t12 values of 36 h at 80degCas suggested by Kirca and Cemeroglu [31]

For the PN the use of the fractional conversion kineticmodel allowed the prediction of anthocyanins content andDPPH-RSA after prolonged heating at dierent tempera-tures (Cinfin) which suggests that the nal degree of degra-dation is temperature dependent (Figure 5)

e activation energy for anthocyanins thermal degra-dation in the simulated juices were 4240plusmn 687 kJmol inPW 4070plusmn 425 kJmol in PCA 2303plusmn 353 kJmol in PS3599plusmn 360 kJmol in PM and 1419plusmn 239 kJmol in PNe estimated Ea values are signicantly lower than thosereported in the literature suggesting a signicantly higherthermal stability of anthocyanins during heat processing ofplum juices For example Danisman [32] reported Ea value

Table 2 Estimated kinetic parameters (rate constant (k) and activation energy Ea) of anthocyanins thermal degradation in plum juices

Juice Temperature degC kmiddot10minus2 (minminus1) R2 t12 (h) Ea (kJmol) R2

PW

50 018plusmn 001a 099 627plusmn 115

4240plusmn 687 090

70 023plusmn 002 085 501plusmn 05790 052plusmn 005 094 218plusmn 023100 087plusmn 011 085 132plusmn 010110 108plusmn 007 098 106plusmn 016120 287plusmn 047 094 040plusmn 002

PCA

50 004plusmn 001 075 2508plusmn 128

4070plusmn 425 099


PS

50 036plusmn 001a 093 313plusmn 015

2303plusmn 353 091


PM

50 011plusmn 008a 074 1003plusmn 038

3599plusmn 360 096


PN

50 821plusmn 349 096 014plusmn 0003

1419plusmn 239 09270 1093plusmn 169 099 010plusmn 000690 1304plusmn 139 099 008plusmn 0001100 1464plusmn 209 099 007plusmn 0005110 2092plusmn 050 099 005plusmn 0002

aStandard errors

00005

0010015

0020025

0030035

004

0 0005 001 0015 002 0025 003 0035 004

Pred

icte

d va

lues

Experimental values

Figure 4 Correlation between the predicted and experimentalCC0 values for PN simulated using (3)


of 6489 kJmol for anthocyanins degradation at the tem-perature range from 70 to 90degC in grape juice Hillmann [33]reported Ea value of 7274 kJmol for the thermal degra-dation of Bordo grape anthocyanins between 70degC and 90degCwhereas Wang and Xu [28] suggested 5895 kJmol for thedegradation of blackberry anthocyanins at temperaturesranging from 60degC to 90degC A higher Ea value for antho-cyanins thermal degradation in blood orange juice andconcentrate was also reported by Kırca and Cemeroglu [31]with values ranging from 732 to 895 kJmol as a function ofsolid content of studied system

In our study the estimated kinetic parameters indicatea greater temperature sensitivity of anthocyanins in PN edegradation of anthocyanins in the presence of citric acidseems to be less susceptible to temperature increase than thatof corresponding juices

34 e Inuence of ermal Treatment on Fluorescence ofPlumJuices e absorption spectra of juices showedmaximaat wavelength ranging from 270 to 410 nm (data not shown)erefore in order to evaluate the eect of heating of an-thocyanins from juices the samples were excited at dierentwavelengths such as 270 nm 300 nm 340 nm and 410nmemost eective uorescence intensities of juices were at theUV absorption maxima of 270 nm erefore these spectrawere further considered for the eect of heating on antho-cyanins in plum juices e short wavelength band in totaluorescence spectra which covers the region of 270ndash330 nmin excitation and 295ndash360 nm in emission is assigned tophenols [34] It should be noted that forty-one phenolics weredetected by Jaiswal [35] in plums comprising caeoylquinicacids feruloylquinic acid p-coumaroylquinic acids methylcaeoylquinates methyl p-coumaroylquinate caeoyl-shikimic acids catechin epicatechin rutin esculin quercetinquercetin-3-O-hexosides dimeric proanthocyanidins trimericproanthocyanidins caeoyl-glucoside feruloyl-glucosidep-coumaroyl-glucoside vanillic acidglucosides 34-dihydroxybenzoyl-glucoside quercetin-3-O-pentosides quercetin-3-O-rhamnoside quercetin-pentoside-rhamnosides and3-p-methoxycinnamoylquinic acid with chlorogenic acids andproanthocyanidins being found as the major compounds

For PW the spectra were dominated by emission bandwith maximum of 342 nm at 25degC whereas red-shifts of

12ndash14nm were observed by heating at temperatures of 110and 120degC respectively (Figure 6) In case of PCA themaximum emission wavelength was found at 341 nmwhereas heating at 110degC caused a red shift of 17 nm and of26 nm at 120degC For PS the spectra were characterized byemission bands with maximum at 344 nm whereas heatingcaused a 7 nm red-shift at 90degC Heating at higher temper-ature caused a 6 nm blue-shift at 100degC followed by a small3 nm red-shift at 120degC Signicant heat-induced structuralchanges were observed in case of PM e uorescencespectra at 25degC had the emission maximum at 340 nmHeating at 70degC caused a signicant 14 nm red-shift in λmaxAt temperatures ranging from 90 to 100degC blue-shift of 6 nmand 4nm were observed followed by 6 nm and 12 nm red-shifts at temperatures of 110degC and 120degC respectively Whenexciting the PN at 270 nm the emission spectra presented oneband with maximum of 354 nm at 25degC Heating causedstructural changes characterized by blue-shifts ranging from4nm at 70degCndash90degC to 9 nm at 110degC Red- and blue-shifts inλmax indicates sequential character of structural changes ofanthocyanins induced by heat treatment

e thermal degradation mechanism of anthocyanins wasexplained by Sadilova [27] involving the transition from thehemiketal to the chalcone form due to the increase of pHConsequently cyanidinpelargonidin glycoside is transformedin chalcone glycoside due to the opening of the ring during theheat treatment followed by deglycosylation and the corre-sponding cleavage of the B- and A-ring with the formation ofthe protocatechuic acid4-hydroxybenzoic acid and respec-tively phloroglucinaaldehyde Four anthocyanin structuresexist in equilibrium avylium cation quinonoidal basecarbinol pseudobase and chalcone Nevertheless it has beensuggested that spectra with maximum at 350nm obtainedwhen excited at 260ndash270nm are characteristic for hemiketalform of anthocyanins [36] e uorescence maximum at350 nm are indicative of relatively simple and less-conjugatedaromatic structural features with the conjugated chromo-phores and electron-donating substituents (such as hydroxylmethoxyl and amino groups) contributing to the uorescencein shorter wavelength regions Hou [37] suggested that thestability of anthocyanins can increase with intermolecular

342

344

346

348

350

352

354

356

335

340

345

350

355

360

365

370

0 20 40 60 80 100 120 140

λ max

(nm

)

λ max

(nm

)

Temperature (degC)

Figure 6 Heat-induced structural changes of anthocyanins fromsimulated and natural plum juices monitored as maximum emissionwavelength (λmax) at dierent temperatures when excited at 270 nmPW (black diamonds) PCA (black squares) PS (black triangles) PM(empty diamonds) and PN (empty squares)ree independent testswere carried out in each case and SD was lower than 35

394041424344454647

00002000400060008

0010012001400160018

40 50 60 70 80 90 100 110 120

DPP

H-R

SAinfin

TAC infin

Temperature (degC)

Figure 5 Correlations between TAC after prolonged heating time(TACinfin) and the corresponding antioxidant activity (DPPHRSAinfin)in PN ( DPPH-RSA TAC)


copigmentation Plums contain mixtures of different com-pounds that may serve as copigments for intermolecular as-sociation with anthocyanins A copigment may be one offlavonoids alkaloids amino acids organic acids nucleotidespolysaccarides metals and anthocyanins themselves [38] Inrelation to the stability anthocyanins may suffer reactions thataltered their structures due to the electronic deficiency of theirflavylium nuclei Our results suggest that anthocyanins areunstable at high temperature which caused a decrease influorescence intensity and red- and blue-shifts in maximumemission wavelengths

4 Conclusions

In this study the thermal stability of extracted anthocyaninsfrom plums was examined in aqueous solutions with orwithout the presence of different compounds such as citricacids glucose and fructose and a mixture of these substances(e degradation kinetics was compared with the thermalbehavior of anthocyanins in natural juice Four anthocyaninswere identified in simulated and natural juices namelycyanidin 3-xylosidecyanidin 3-glucoside cyanidin 3-rutino-side peonidin 3-glucoside and peonidin 3-rutinoside whereasthe real systems contained fourmore unidentified compounds(e heating at 100degC caused a significant decrease in antho-cyanins content with a protective effect found in simulatedjuices containing citric acid and sugars (ree anthocyaninswere completely degraded in the real system whereas insimulated juices containing citric acid and sugars an increasein C3G and P3G was found

In order to assess the effect of high temperature on totalanthocyanin content in the simulated and natural plumjuices the first-order and fractional conversion kineticmodels were used (e values reported for the activationenergies highlighted that these bioactive compounds presenta significant stability during thermal treatment Fluores-cence spectroscopy technique was used as an additionaltechnique to evidence the heat treatment effects on the plumjuices (e most effective fluorescence intensities of juiceswere at the UV absorption maxima of 270 nm Heatingcaused significant red- and blue-shifts in emission maximasuggesting important structural events

Based on our results further studies are currently de-veloped by our research group for the determination ofappropriate processing and formulation protocols that couldlead to a more efficient utilization of plum anthocyanins asnatural pigments in food products

Conflicts of Interest

(e authors declare that there are no conflicts of interestregarding the publication of this paper

Acknowledgments

(is work was supported by a grant of the Ministry ofNational Education CNCSndashUEFISCDI Project no PN-II-ID-PCE-2012-4-0509

References

[1] M Igual E Garcıa-Martınez M M Camacho andN Martınez-Navarrete ldquoChanges in flavonoid content ofgrapefruit juice caused by thermal treatment and storagerdquoInnovative Food Science and Emerging Technologies vol 12no 2 pp 153ndash162 2011

[2] M Ding R Feng S Y Wang et al ldquoCyanidin-3-glucosidea natural product derived from blackberry exhibits chemo-preventive and chemotherapeutic activityrdquo Journal of Bi-ological Chemistry vol 281 no 25 pp 17359ndash17368 2006

[3] D R Bell and K Gochenaur ldquoDirect vasoactive and vaso-protective properties of anthocyanin-rich extractsrdquo Journal ofApplied Physiology vol 100 no 4 pp 1164ndash1170 2006

[4] M H Grace D M Ribnicky P Kuhn et al ldquoHypoglycemicactivity of a novel anthocyanin-rich formulation from low-bush blueberry Vaccinium angustifolium Aitonrdquo Phytome-dicine vol 16 no 5 pp 406ndash415 2010

[5] S Ping-Hsiao C Yin-Ching L Jiunn-Wang W Ming-Fuand Y Gow-Chin ldquoAntioxidant and cognitive promotioneffects of anthocyanin-rich mulberry (Morus atropurpurea L)on senescence-accelerated mice and prevention of Alz-heimerrsquos diseaserdquo Journal of Nutrional Biochemistry vol 21no 7 pp 598ndash605 2010

[6] F J Francis ldquoAnthocyanins as food colorsrdquo Food Technologyvol 29 no 5 pp 52ndash54 1975

[7] G Gradinaru C G Biliaderis S Kallithraka P Kefalas andC Garcia-Viguera ldquo(ermal stability ofHibiscus sabdariffa Lanthocyanins in solution and in solid state effects ofcopigmentation and glass transitionrdquo Food Chemistry vol 83no 3 pp 423ndash436 2003

[8] M Turturica N Stanciuc G Bahrim and G Rapeanu ldquoEffectof thermal treatment on phenolic compounds from plum(Prunus domestica) extractsmdasha kinetic studyrdquo Journal of FoodEngineering vol 171 pp 200ndash207 2016

[9] V Usenik J Fabcic and F Stampar ldquoSugars organic acidsphenolic composition and antioxidant activity of sweet cherry(Prunus avium L)rdquo Food Chemistry vol 107 no 1 pp 185ndash1922008

[10] M Kopjar K Jaksic and V Pilizota ldquoInfluence of sugars andchlorogenic acid addition on anthocyanin content antioxi-dant activity and color of blackberry juice during storagerdquoJournal of Food Processing and Preservation vol 36 no 6pp 545ndash552 2012

[11] G Mazza and E Miniati Anthocyanins in Fruits Vegetablesand Grains CRC Press Inc Boca Raton FL USA 1993

[12] P Mazzaracchio P Pifferi M Kindt A Munyaneza andG Barbiroli ldquoInteractions between anthocyanins and organicfood molecules in model systemsrdquo International Journal ofFood Science amp Technology vol 39 no 1 pp 53ndash59 2004

[13] D D Pozo-Insfran A D Follo-Martinez S T Talcott andC H Brenes ldquoStability of copigmented anthocyanins andascorbic acid in muscadine grape juice processed by highhydrostatic pressurerdquo Journal of Food Science vol 72 no 4pp S247ndashS253 2007

[14] E M Hubbermann A Heins H Stockmann and K SchwarzldquoInfluence of acids salt sugars and hydrocolloids on thecolour stability of anthocyanin rich black currant and el-derberry concentratesrdquo European Food Research Technologyvol 223 no 1 pp 83ndash90 2006

[15] M Kopjar V Pilizota D Subaric and J Babic ldquoPrevention ofthermal degradation of red currant juice anthocyanins byphenolic compounds additionrdquo Croatian Journal of FoodScience and Technology vol 1 no 1 pp 24ndash30 2009


[16] K Solyom R Sola M J Cocero and R B Mato ldquo(ermaldegradation of grape marc polyphenolsrdquo Food Chemistryvol 159 pp 361ndash366 2014

[17] M M Giusti and R E Wrolstad ldquoAcylated anthocyaninsfrom edible sources and their applications in food systemsrdquoBiochemical Engineering Journal vol 14 no 3 pp 217ndash2252003

[18] E Abd-Elhady ldquoEffect of citric acid calcium lactate and lowtemperature prefreezing treatment on the quality of frozenstrawberryrdquo Annals of Agricultural Science vol 59 no 1pp 69ndash75 2014

[19] M V Martinez and J R Whitaker ldquo(e biochemistry andcontrol of enzymatic browningrdquo Trends of Food Science andTechnology vol 6 no 6 pp 195ndash200 1995

[20] C A Shaheer P Hafeeda R Kumar et al ldquoEffect of thermaland thermosonication on anthocyanin stability in jamun(Eugenia jambolana) fruit juicerdquo International Food ResearchJournal vol 21 pp 2189ndash2194 2014

[21] F Francis ldquoA new group of food colourantsrdquo Trends in FoodScience and Technology vol 3 pp 27ndash30 1992

[22] X Wu and R L Prior ldquoSystematic identification and char-acterization of anthocyanins by HPLC-ESI-MSMS in com-mon foods in the United States Fruits and Berriesrdquo Journal ofAgricultural and Food Chemistry vol 53 no 7 pp 2589ndash2599 2005

[23] M Rubinskiene P Viskelis I Jasutiene R Viskeliene andC Bobinas ldquoImpact of various factors on the composition andstability of black currant anthocyaninsrdquo Food Research In-ternational vol 38 no 8-9 pp 867ndash871 2005

[24] L Szaloki-Dorko G Vegvari M Ladanyi G Ficzek andM Steger-Mate ldquoDegradation of anthocyanin content in sourcherry juice during heat treatmentrdquo Food Technology andBiotechnology vol 53 pp 354ndash360 2015

[25] J Volden G I A Borge G B Bengtsson M HansenI E (ygesen and T B Wicklund ldquoEffect of thermaltreatment on glucosinolates and antioxidant-related param-eters in red cabbage (Brassica oleracea L ssp capitata frubra)rdquo Food Chemistry vol 109 no 3 pp 595ndash605 2008

[26] B Nayak J D J Berrios J R Powers and J Tang ldquo(ermaldegradation of anthocyanins from purple potato (Cv PurpleMajesty) and impact on antioxidant capacityrdquo Journal ofAgricultural and Food Chemistry vol 59 no 20 pp 11040ndash11049 2011

[27] E Sadilova R Carle and F C Stintzing ldquo(ermal degra-dation of anthocyanins and its impact on colour and in vitroantioxidant capacityrdquoMolecular Nutrition and Food Researchvol 51 no 12 pp 1461ndash1471 2007

[28] W D Wang and S Y Xu ldquoDegradation kinetics of antho-cyanins in blackberry juice and concentraterdquo Journal of FoodEngineering vol 82 no 3 pp 271ndash275 2007

[29] N Harbourne J C Jacquier D J Morgan and J G LyngldquoDetermination of the degradation kinetics of anthocyanins ina model juice system using isothermal and non-isothermalmethodsrdquo Food Chemistry vol 111 no 1 pp 204ndash208 2008

[30] B Cemeroglu S Velioglu and S Isik ldquoDegradation kineticsof anthocyanins in sour cherry juice and concentraterdquo Journalof Food Science vol 59 no 6 pp 1216ndash1218 1994

[31] A Kırca and B Cemeroglu ldquoDegradation kinetics of an-thocyanins in blood orange juice and concentraterdquo FoodChemistry vol 81 no 4 pp 583ndash587 2003

[32] G Danisman E Arslan and A K Toklucu ldquoKinetic analysisof anthocyanin degradation and polymeric colour formationin grape juice during heatingrdquo Czech Journal of Food Sciencevol 33 no 2 pp 103ndash108 2015

[33] M C R Hillmann V M Burin and M T Bordignon-Luizldquo(ermal degradation kinetics of anthocyanins in grape juiceand concentraterdquo International Journal of Food Science andTechnology vol 46 pp 1997ndash2000 2011

[34] E Sikorska I Khmelinskii andM Sikorski ldquoAnalysis of oliveoils by fluorescence spectroscopy methods and applicationsrdquoin Olive Oil-Constituents Quality Health Properties andBioconversions D Boskou Ed InTech London UK 2012

[35] R Jaiswal H Karakose S Ruhmann et al ldquoIdentification ofphenolic compounds in plum fruits (Prunus salicina L andPrunus domestica L) by high-performance liquidchromatographytandem mass spectrometry and character-ization of varieties by quantitative phenolic fingerprintsrdquoJournal of Agricultural and Food Chemistry vol 61 no 49pp 12020ndash12031 2013

[36] D Costa AM Galvatildeoa R E Di Paolo et al ldquoPhotochemistryof the hemiketal form of anthocyanins and its potential role inplant protection from UV-B radiationrdquo Tetrahedron vol 71no 20 pp 3157ndash3162 2015

[37] Z H Hou P Y Qin Y Zhang S H Cui and G X RenldquoIdentification of anthocyanins isolated from black rice(Oryza sativa L) and their degradation kineticsrdquo Food Re-search International vol 50 no 2 pp 691ndash697 2013

[38] G Mazza and R Brouillard ldquo(e mechanism of copigmen-tation of anthocyanins in aqueous solutionsrdquo Phytochemistryvol 29 no 4 pp 1097ndash1102 1990


Hindawiwwwhindawicom

International Journal of

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Zoology

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Anatomy Research International

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MicrobiologyHindawiwwwhindawicom

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Submit your manuscripts atwwwhindawicom

are susceptible to degradation [10] (e stability of the an-thocyanins depends on several factors such as pH temper-ature oxygen metallic ions ascorbic acid sugars and theirdegradation products [11] It has been reported that antho-cyanins exhibit higher stability under acidic conditions butunder normal processing and storage conditions readilyconvert to colorless derivatives and subsequently to insolublebrown pigments [7](e red plum juice color is influenced bythermal treatment used to preserve and to extend the shelf lifeof juices During thermal treatment the anthocyanins de-grade due to their high reactivity and also they may poly-merize which is related to degradation of color and loss ofnutritional values in food products [12] Several studies wereperformed in order to evaluate the stability of anthocyaninsthrough addition of sugars acids hydrocolloids salts anddifferent phenolic compounds in various fruit productsduring thermal treatment [12ndash15] By studying the data fromthe literature it can be assumed that the thermal degradationof anthocyanins depends onmatrices fromwhich it originatesand the complexity of the heating environment It is clear thatthe raw materialsrsquo variability and the different heating con-ditions are hardly comparable in terms of temperature andtime solid content or the presence of extraction solvent [16](ere is a need to relate the kinetics of thermal degradation ofanthocyanins concomitant to increase the complexity of thesystem (erefore the main objective was the evaluation ofthermal degradation of anthocyanins from plums in mediumwith increased complexity during heating at a temperaturerange between 50 and 120degC on a kinetic basis (e HPLCtechnique was employed to evaluate the degradation of in-dividual anthocyanins identified in plum juices at tempera-tures of 25degC and 100degC after 20minutes of holding Since redplum juices are a good source of antioxidants the change inantioxidant capacity during thermal treatment was also in-vestigated Intrinsic fluorescence spectroscopy technique wasused as an additional technique to extend the possibilities ofanalysis of the heat-induced changes in anthocyanins

2 Materials and Methods

21 Chemicals 22-Diphenyl-1-picrylhydrazyl (DPPH) 6-Hydroxy-2578-tetramethylchromane-2-carboxylic acid (Tro-lox) sodiumacetate potassium chloride ethanol andmethanol(HPLC grade) were obtained from Sigma Aldrich SteinheimGermany Cyanidin and pelargonidin standards were obtainedfrom Extrasynthese (ZI Lyon Nord France)

22 Juices Preparation Plums (Prunus domestica Vanettevariety) were provided from the local market (Galati county)during JunendashJuly 2015 Fruits samples were washed withwater in the ratio of 1 2 (ww) After washing the skins weremanually separated and then were washed with distilledwater Finally they were blotted on paper towels to removeany residual pulp (e extraction of anthocyanins fromfreeze-dried red plums was performed according to a pre-viously described procedure [8]

Plum juices were obtained as following

(i) PW (plum juice in water) was obtained from theconcentrated plum extract (lyophilized plum skins

70 ethanol ratio of 1 8) which was then dissolvedin 20mL distilled water

(ii) PCA (plum juice with citric acid) was obtained inthe same way as PW the difference being the ad-dition of citric acid (2213 g citric acidL extract)

(iii) PS (plum juice with sugars) was obtained in the sameway as PW with the addition of glucose and fructose(244 g glucoseL extract and 6197 g fructoseL extract)

(iv) PM (plum juice with mixture) represents the juiceobtained with the addition of all the above men-tioned compounds in the same ratio

(v) PN (natural plum juice) was obtained from 250 gplums that were crushed and afterwards 1 g ofZymorouge enzyme was added and left for 24 h inorder to achieve the extraction of the pigments (eobtained juice was then filtered using a cheese cloth

23 Heat Treatment A volume of 200 microL of juices was filledin Eppendorf tubes (1 cm diameter) and heated at tempera-tures ranging from 50 to 120degC for 30min for the fluorescencespectroscopy experiments (e same temperature range from50degC to 120deg but different times (0ndash60min) were used forthermal treatment in the case of thermal degradation kineticstudies

Heating experiments were conducted in a thermostaticoil bath (Nahita 6023 Navarra Spain) according to a pre-viously described procedure [8]

24 HPLC Analysis of Anthocyanins (e identification andquantification of plum juice anthocyanins were made usinga (ermo Finnigan Surveyor HPLC system controlled byXcalibur software system (Finnigan Surveyor LC (ermoScientific USA) (e column used for the separation ofplum anthocyanins was Synergi 4u Fusion-RP 80A(150mmtimes 46mm 4 μm)(e column was operated at 25degCat a wavelength of 520 nm (e elution profile was ac-complished with 100 methanol (A) and 10 formic acid(B) (e elution program employed was 0ndash20min 9ndash35(A) 20ndash30min 35 (A) 30ndash40min 35ndash50 (A) and40ndash55min 50ndash9 (A) (e injection amount was 10 μL ata flow rate of 1mLmin

25 Phytochemicals Analysis Total monomeric anthocya-nins (TAC) and free radical scavenging activity (DPPHRSA)of juices were estimated according to our earlier report [8]

26 Fluorescence Spectroscopy Measurements Fluorescencemeasurements were carried out using a LS-55 luminescencespectrometer (PerkinElmer Life Sciences Shelton CT USA)as described earlier by Turturica [8]

27 Mathematical Models and Kinetic Analysis (e degra-dation kinetics of TAC in PW PCA PS and PM weredescribed by fitting the first order kinetic model (1) to ex-perimental data


C

C0 eminuskt

(1)






t12 minusln 05

k (3)












ndash10000

90000

190000

290000

390000

490000

590000

10 15 20

Abs

orba

nce a

t 520

nm

(μA

U)

Time (min)

PW 25degCPW 100degC

2

3

(a)

Time (min)


ndash10000

90000

190000

290000

390000

490000

590000

10 12 14 16 18 20

Abs

orba

nce a

t 520

nm

(μA

U)

(b)

ndash10000

90000

190000

290000

390000

490000

590000

10 12 14 16 18 20

Abs

orba

nce a

t 520

nm

(μA

U)

Time (min)

PS 25degCPS 100degC

(c)

ndash10000

90000

190000

290000

390000

490000

590000

690000

10 12 14 16 18 20

Abs

orba

nce a

t 520

nm

(μA

U)

Time (min)

PM 25degCPM 100degC

(d)

0

200000

400000

600000

800000

1000000

10 15 20

Abs

orba

nce a

t 520

nm

(μA

U)

Time (min)

PN 25degCPN 100degC

(e)



Tabl

e1

Antho

cyaninscontentinPW

PCAP

SPM

and

PNexpressedas

μgg

at25

deg Candafter20

min

oftreatm

enta

t100degC

Juice

PWPC

APS

PMPN

Antho

cyanin

25deg C

100degC

25deg C

100degC

25deg C

100degC

25deg C

100degC

25deg C

100degC

C3G

3789plusmn287

2817plusmn178

3230plusmn125

2702plusmn178

2147plusmn199

2316plusmn154

2462plusmn141

3540plusmn124

8705plusmn152

725plusmn009

C3R

43461plusmn1154

33642plusmn1598

55955plusmn5221

30908plusmn1178

40336plusmn1432

31647plusmn1756

42107plusmn1627

39699plusmn501

52588plusmn314

1830plusmn187

P3G

00

093plusmn012

065plusmn010

00

158plusmn045

416plusmn101

1636plusmn048

0P3

R23678plusmn1454

18336plusmn1024

30071plusmn1124

16622plusmn236

21721plusmn1087

17465plusmn947

22487plusmn1147

21512plusmn1421

41554plusmn569

3648plusmn294

C3G

cyanidin3-xylosid

ecyanidin

3-glucosideC3R

cyanidin3-rutin

osideP3

Gp


Rpeon

idin

3-rutin

oside








00 10 20 30 40 50 60

Ln (C

C0)

Heating time (min)

(a)

Ln (C

C0)


001 0 10 20 30 40 50 60Heating time (min)

(b)

ndash05ndash045

ndash04ndash035

ndash03ndash025

ndash02ndash015

ndash01ndash005

00 10 20 30 40 50 60

Log

(CC

0)

Heating time (min)

(c)

Ln (C

C0)

ndash039ndash034

ndash024ndash029


001 0 10 20 30 40 50 60Heating time (min)

(d)


00005

0010015

0020025

0030035

004

0 10 20 30 40 50 60

C

Heating time (min)











PW

50 018plusmn 001a 099 627plusmn 115

4240plusmn 687 090


PCA

50 004plusmn 001 075 2508plusmn 128

4070plusmn 425 099


PS

50 036plusmn 001a 093 313plusmn 015

2303plusmn 353 091


PM

50 011plusmn 008a 074 1003plusmn 038

3599plusmn 360 096


PN

50 821plusmn 349 096 014plusmn 0003


aStandard errors

00005

0010015

0020025

0030035

004

0 0005 001 0015 002 0025 003 0035 004

Pred

icte

d va

lues

Experimental values









342

344

346

348

350

352

354

356

335

340

345

350

355

360

365

370

0 20 40 60 80 100 120 140

λ max

(nm

)

λ max

(nm

)

Temperature (degC)


394041424344454647

00002000400060008

0010012001400160018

40 50 60 70 80 90 100 110 120

DPP

H-R

SAinfin

TAC infin

Temperature (degC)




4 Conclusions






Acknowledgments


References











































Volume 2018

Zoology











Volume 2018

















Advances in




Enzyme Research





Volume 2018


C

C0 eminuskt

(1)






t12 minusln 05

k (3)












ndash10000

90000

190000

290000

390000

490000

590000

10 15 20

Abs

orba

nce a

t 520

nm

(μA

U)

Time (min)

PW 25degCPW 100degC

2

3

(a)

Time (min)


ndash10000

90000

190000

290000

390000

490000

590000

10 12 14 16 18 20

Abs

orba

nce a

t 520

nm

(μA

U)

(b)

ndash10000

90000

190000

290000

390000

490000

590000

10 12 14 16 18 20

Abs

orba

nce a

t 520

nm

(μA

U)

Time (min)

PS 25degCPS 100degC

(c)

ndash10000

90000

190000

290000

390000

490000

590000

690000

10 12 14 16 18 20

Abs

orba

nce a

t 520

nm

(μA

U)

Time (min)

PM 25degCPM 100degC

(d)

0

200000

400000

600000

800000

1000000

10 15 20

Abs

orba

nce a

t 520

nm

(μA

U)

Time (min)

PN 25degCPN 100degC

(e)



Tabl

e1

Antho

cyaninscontentinPW

PCAP

SPM

and

PNexpressedas

μgg

at25

deg Candafter20

min

oftreatm

enta

t100degC

Juice

PWPC

APS

PMPN

Antho

cyanin

25deg C

100degC

25deg C

100degC

25deg C

100degC

25deg C

100degC

25deg C

100degC

C3G

3789plusmn287

2817plusmn178

3230plusmn125

2702plusmn178

2147plusmn199

2316plusmn154

2462plusmn141

3540plusmn124

8705plusmn152

725plusmn009

C3R

43461plusmn1154

33642plusmn1598

55955plusmn5221

30908plusmn1178

40336plusmn1432

31647plusmn1756

42107plusmn1627

39699plusmn501

52588plusmn314

1830plusmn187

P3G

00

093plusmn012

065plusmn010

00

158plusmn045

416plusmn101

1636plusmn048

0P3

R23678plusmn1454

18336plusmn1024

30071plusmn1124

16622plusmn236

21721plusmn1087

17465plusmn947

22487plusmn1147

21512plusmn1421

41554plusmn569

3648plusmn294

C3G

cyanidin3-xylosid

ecyanidin

3-glucosideC3R

cyanidin3-rutin

osideP3

Gp


Rpeon

idin

3-rutin

oside








00 10 20 30 40 50 60

Ln (C

C0)

Heating time (min)

(a)

Ln (C

C0)


001 0 10 20 30 40 50 60Heating time (min)

(b)

ndash05ndash045

ndash04ndash035

ndash03ndash025

ndash02ndash015

ndash01ndash005

00 10 20 30 40 50 60

Log

(CC

0)

Heating time (min)

(c)

Ln (C

C0)

ndash039ndash034

ndash024ndash029


001 0 10 20 30 40 50 60Heating time (min)

(d)


00005

0010015

0020025

0030035

004

0 10 20 30 40 50 60

C

Heating time (min)











PW

50 018plusmn 001a 099 627plusmn 115

4240plusmn 687 090


PCA

50 004plusmn 001 075 2508plusmn 128

4070plusmn 425 099


PS

50 036plusmn 001a 093 313plusmn 015

2303plusmn 353 091


PM

50 011plusmn 008a 074 1003plusmn 038

3599plusmn 360 096


PN

50 821plusmn 349 096 014plusmn 0003


aStandard errors

00005

0010015

0020025

0030035

004

0 0005 001 0015 002 0025 003 0035 004

Pred

icte

d va

lues

Experimental values









342

344

346

348

350

352

354

356

335

340

345

350

355

360

365

370

0 20 40 60 80 100 120 140

λ max

(nm

)

λ max

(nm

)

Temperature (degC)


394041424344454647

00002000400060008

0010012001400160018

40 50 60 70 80 90 100 110 120

DPP

H-R

SAinfin

TAC infin

Temperature (degC)




4 Conclusions






Acknowledgments


References











































Volume 2018

Zoology











Volume 2018

















Advances in




Enzyme Research





Volume 2018


ndash10000

90000

190000

290000

390000

490000

590000

10 15 20

Abs

orba

nce a

t 520

nm

(μA

U)

Time (min)

PW 25degCPW 100degC

2

3

(a)

Time (min)


ndash10000

90000

190000

290000

390000

490000

590000

10 12 14 16 18 20

Abs

orba

nce a

t 520

nm

(μA

U)

(b)

ndash10000

90000

190000

290000

390000

490000

590000

10 12 14 16 18 20

Abs

orba

nce a

t 520

nm

(μA

U)

Time (min)

PS 25degCPS 100degC

(c)

ndash10000

90000

190000

290000

390000

490000

590000

690000

10 12 14 16 18 20

Abs

orba

nce a

t 520

nm

(μA

U)

Time (min)

PM 25degCPM 100degC

(d)

0

200000

400000

600000

800000

1000000

10 15 20

Abs

orba

nce a

t 520

nm

(μA

U)

Time (min)

PN 25degCPN 100degC

(e)



Tabl

e1

Antho

cyaninscontentinPW

PCAP

SPM

and

PNexpressedas

μgg

at25

deg Candafter20

min

oftreatm

enta

t100degC

Juice

PWPC

APS

PMPN

Antho

cyanin

25deg C

100degC

25deg C

100degC

25deg C

100degC

25deg C

100degC

25deg C

100degC

C3G

3789plusmn287

2817plusmn178

3230plusmn125

2702plusmn178

2147plusmn199

2316plusmn154

2462plusmn141

3540plusmn124

8705plusmn152

725plusmn009

C3R

43461plusmn1154

33642plusmn1598

55955plusmn5221

30908plusmn1178

40336plusmn1432

31647plusmn1756

42107plusmn1627

39699plusmn501

52588plusmn314

1830plusmn187

P3G

00

093plusmn012

065plusmn010

00

158plusmn045

416plusmn101

1636plusmn048

0P3

R23678plusmn1454

18336plusmn1024

30071plusmn1124

16622plusmn236

21721plusmn1087

17465plusmn947

22487plusmn1147

21512plusmn1421

41554plusmn569

3648plusmn294

C3G

cyanidin3-xylosid

ecyanidin

3-glucosideC3R

cyanidin3-rutin

osideP3

Gp


Rpeon

idin

3-rutin

oside








00 10 20 30 40 50 60

Ln (C

C0)

Heating time (min)

(a)

Ln (C

C0)


001 0 10 20 30 40 50 60Heating time (min)

(b)

ndash05ndash045

ndash04ndash035

ndash03ndash025

ndash02ndash015

ndash01ndash005

00 10 20 30 40 50 60

Log

(CC

0)

Heating time (min)

(c)

Ln (C

C0)

ndash039ndash034

ndash024ndash029


001 0 10 20 30 40 50 60Heating time (min)

(d)


00005

0010015

0020025

0030035

004

0 10 20 30 40 50 60

C

Heating time (min)











PW

50 018plusmn 001a 099 627plusmn 115

4240plusmn 687 090


PCA

50 004plusmn 001 075 2508plusmn 128

4070plusmn 425 099


PS

50 036plusmn 001a 093 313plusmn 015

2303plusmn 353 091


PM

50 011plusmn 008a 074 1003plusmn 038

3599plusmn 360 096


PN

50 821plusmn 349 096 014plusmn 0003


aStandard errors

00005

0010015

0020025

0030035

004

0 0005 001 0015 002 0025 003 0035 004

Pred

icte

d va

lues

Experimental values









342

344

346

348

350

352

354

356

335

340

345

350

355

360

365

370

0 20 40 60 80 100 120 140

λ max

(nm

)

λ max

(nm

)

Temperature (degC)


394041424344454647

00002000400060008

0010012001400160018

40 50 60 70 80 90 100 110 120

DPP

H-R

SAinfin

TAC infin

Temperature (degC)




4 Conclusions






Acknowledgments


References











































Volume 2018

Zoology











Volume 2018

















Advances in




Enzyme Research





Volume 2018


Tabl

e1

Antho

cyaninscontentinPW

PCAP

SPM

and

PNexpressedas

μgg

at25

deg Candafter20

min

oftreatm

enta

t100degC

Juice

PWPC

APS

PMPN

Antho

cyanin

25deg C

100degC

25deg C

100degC

25deg C

100degC

25deg C

100degC

25deg C

100degC

C3G

3789plusmn287

2817plusmn178

3230plusmn125

2702plusmn178

2147plusmn199

2316plusmn154

2462plusmn141

3540plusmn124

8705plusmn152

725plusmn009

C3R

43461plusmn1154

33642plusmn1598

55955plusmn5221

30908plusmn1178

40336plusmn1432

31647plusmn1756

42107plusmn1627

39699plusmn501

52588plusmn314

1830plusmn187

P3G

00

093plusmn012

065plusmn010

00

158plusmn045

416plusmn101

1636plusmn048

0P3

R23678plusmn1454

18336plusmn1024

30071plusmn1124

16622plusmn236

21721plusmn1087

17465plusmn947

22487plusmn1147

21512plusmn1421

41554plusmn569

3648plusmn294

C3G

cyanidin3-xylosid

ecyanidin

3-glucosideC3R

cyanidin3-rutin

osideP3

Gp


Rpeon

idin

3-rutin

oside








00 10 20 30 40 50 60

Ln (C

C0)

Heating time (min)

(a)

Ln (C

C0)


001 0 10 20 30 40 50 60Heating time (min)

(b)

ndash05ndash045

ndash04ndash035

ndash03ndash025

ndash02ndash015

ndash01ndash005

00 10 20 30 40 50 60

Log

(CC

0)

Heating time (min)

(c)

Ln (C

C0)

ndash039ndash034

ndash024ndash029


001 0 10 20 30 40 50 60Heating time (min)

(d)


00005

0010015

0020025

0030035

004

0 10 20 30 40 50 60

C

Heating time (min)











PW

50 018plusmn 001a 099 627plusmn 115

4240plusmn 687 090


PCA

50 004plusmn 001 075 2508plusmn 128

4070plusmn 425 099


PS

50 036plusmn 001a 093 313plusmn 015

2303plusmn 353 091


PM

50 011plusmn 008a 074 1003plusmn 038

3599plusmn 360 096


PN

50 821plusmn 349 096 014plusmn 0003


aStandard errors

00005

0010015

0020025

0030035

004

0 0005 001 0015 002 0025 003 0035 004

Pred

icte

d va

lues

Experimental values









342

344

346

348

350

352

354

356

335

340

345

350

355

360

365

370

0 20 40 60 80 100 120 140

λ max

(nm

)

λ max

(nm

)

Temperature (degC)


394041424344454647

00002000400060008

0010012001400160018

40 50 60 70 80 90 100 110 120

DPP

H-R

SAinfin

TAC infin

Temperature (degC)




4 Conclusions






Acknowledgments


References











































Volume 2018

Zoology











Volume 2018

















Advances in




Enzyme Research





Volume 2018








00 10 20 30 40 50 60

Ln (C

C0)

Heating time (min)

(a)

Ln (C

C0)


001 0 10 20 30 40 50 60Heating time (min)

(b)

ndash05ndash045

ndash04ndash035

ndash03ndash025

ndash02ndash015

ndash01ndash005

00 10 20 30 40 50 60

Log

(CC

0)

Heating time (min)

(c)

Ln (C

C0)

ndash039ndash034

ndash024ndash029


001 0 10 20 30 40 50 60Heating time (min)

(d)


00005

0010015

0020025

0030035

004

0 10 20 30 40 50 60

C

Heating time (min)











PW

50 018plusmn 001a 099 627plusmn 115

4240plusmn 687 090


PCA

50 004plusmn 001 075 2508plusmn 128

4070plusmn 425 099


PS

50 036plusmn 001a 093 313plusmn 015

2303plusmn 353 091


PM

50 011plusmn 008a 074 1003plusmn 038

3599plusmn 360 096


PN

50 821plusmn 349 096 014plusmn 0003


aStandard errors

00005

0010015

0020025

0030035

004

0 0005 001 0015 002 0025 003 0035 004

Pred

icte

d va

lues

Experimental values









342

344

346

348

350

352

354

356

335

340

345

350

355

360

365

370

0 20 40 60 80 100 120 140

λ max

(nm

)

λ max

(nm

)

Temperature (degC)


394041424344454647

00002000400060008

0010012001400160018

40 50 60 70 80 90 100 110 120

DPP

H-R

SAinfin

TAC infin

Temperature (degC)




4 Conclusions






Acknowledgments


References











































Volume 2018

Zoology











Volume 2018

















Advances in




Enzyme Research





Volume 2018










PW

50 018plusmn 001a 099 627plusmn 115

4240plusmn 687 090


PCA

50 004plusmn 001 075 2508plusmn 128

4070plusmn 425 099


PS

50 036plusmn 001a 093 313plusmn 015

2303plusmn 353 091


PM

50 011plusmn 008a 074 1003plusmn 038

3599plusmn 360 096


PN

50 821plusmn 349 096 014plusmn 0003


aStandard errors

00005

0010015

0020025

0030035

004

0 0005 001 0015 002 0025 003 0035 004

Pred

icte

d va

lues

Experimental values









342

344

346

348

350

352

354

356

335

340

345

350

355

360

365

370

0 20 40 60 80 100 120 140

λ max

(nm

)

λ max

(nm

)

Temperature (degC)


394041424344454647

00002000400060008

0010012001400160018

40 50 60 70 80 90 100 110 120

DPP

H-R

SAinfin

TAC infin

Temperature (degC)




4 Conclusions






Acknowledgments


References











































Volume 2018

Zoology











Volume 2018

















Advances in




Enzyme Research





Volume 2018








342

344

346

348

350

352

354

356

335

340

345

350

355

360

365

370

0 20 40 60 80 100 120 140

λ max

(nm

)

λ max

(nm

)

Temperature (degC)


394041424344454647

00002000400060008

0010012001400160018

40 50 60 70 80 90 100 110 120

DPP

H-R

SAinfin

TAC infin

Temperature (degC)




4 Conclusions






Acknowledgments


References











































Volume 2018

Zoology











Volume 2018

















Advances in




Enzyme Research





Volume 2018



4 Conclusions






Acknowledgments


References











































Volume 2018

Zoology











Volume 2018

















Advances in




Enzyme Research





Volume 2018




























Volume 2018

Zoology











Volume 2018

















Advances in




Enzyme Research





Volume 2018




Volume 2018

Zoology











Volume 2018

















Advances in




Enzyme Research





Volume 2018


Documents

Journal of Food Quality Thermal Degradation of Plum …downloads.hindawi.com/journals/jfq/2018/1598756.pdf · 2019-07-30 · Research Article Journal of Food Quality Thermal Degradation