Handbook of Fruit and Vegetable Flavors (Hui/Vegetable Flavors) || Chili Flavor

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Handbook of Fruit and Vegetable Flavors, Edited by Y. H. HuiCopyright © 2010 John Wiley & Sons, Inc.

INTRODUCTION

Chilis are one of the most ancient constituents of spices and condiments. The dis-covery of chilis was credited to Christopher Columbus. It is an irony that Columbus, who wanted to reach India by sea route, found the American continent and discov-ered the presence of chilis rather than the other exotic spices associated with India. The ancient texts of India do mention the presence of chilis. However, the American continent was attributed with the origin of wild varieties of chilis as such. The usage of the word “ chilli, ” usually spelt as “ chili ” in the United States, separates the com-modity from black or white peppers, which are also pungent spice species and are highly popular in the exotic world of spices.

Chilis in a fresh state are rich sources of vitamin C, and isolation of vitamin C from paprika attracted worldwide attention during the exploratory period of vitamin C metabolism and the establishment of ascorbic acid as one of the most vital nutri-ents associated with a number of metabolic reactions in human beings. Chilis also possess interesting medicinal properties and are usually known as potential stimu-lants and are carminative in nature. The ancient texts describe the curative role of chilis in rheumatism and in skin diseases. Modern research did herald chilis as potential sources of antioxidants and other functional ingredients of nutraceutical importance. Ferrari and Aillaud (1971) gave a detailed bibliography concerning the various principal ingredients of chilis. Capsanthin is the most important pigment of capsicum and the pungent principle is capsaicin, which is present in the placenta and is said to retain its pungency even at a concentration as low as 1 ppm.

BIOLOGY AND CLASSIFICATION

The genus Capsicum belongs to the family Solanaceae, which has about 90 genera and approximately 2000 species of different habits. Heiser (1969) described around

CHAPTER 41

Chili Flavor

P.S. RAJU , O.P. CHAUHAN , and A.S. BAWA

Defence Food Research Laboratory

776 HANDBOOK OF FRUIT AND VEGETABLE FLAVORS

TABLE 41.1. Key to the Cultivated Species of Capsicum

Index Code Description Botanical Nomenclature

A Corolla lobes purple, seeds black C. pubescens AA Corolla lobes white or greenish white, rarely

purple, seeds light in color

B Corolla white with yellow or tan markings on throat, anthers yellow

C. baccatum

BB Corolla without yellow markings on throat, anthers light blue to purple

C Corolla usually clear or dingy white, pedicels usually solitary at a node

C. annuum

CC Corolla usually greenish white, pedicels usually more than one at a node

D Pedicels usually two per node, erect at anthesis, without distinct constriction with the calyx

C. frutescens

DD Pedicels usually three to fi ve per node, usually curved, with distinct circular constriction with the calyx

C. chinense

20 wild species of capsicum , most of which are of South American origin and two of the genera, Capsicum annuum var. glabriusculum and Capsicum frutescens , extending through Middle America to the Southern United States. As such, the species coming under chili peppers are extremely variable particularly in the char-acters of the fruit, and the variation is parallel. Linnaus recognized two species, that is, C. annuum and C. frutescens , in the Species Plantarum , published in the year 1753. During the next 100 years, a great number of additional species were described based largely on the characters of the fruit, so that when the genus was revised, 100 binomials were described (Irish 1898 ). The widely accepted classifi cation was given by Heiser and Smith (1953) in which fi ve cultivated species were reported following the key given in Table 41.1 .

Small - fruited forms of the species occur widely across Southern United States through Mexico and Central America to Northern America. Heiser and Pickersgill (1975) revised C. annuum var. minimum (Miller) Heiser to C. annuum var. glabri-usculum (Dunal) Heiser and Pickersgill. These fruits are extremely pungent and are not cultivated, and the origin is largely restricted to wild growth. C. annuum var. annuum is an economically important chili variety, and it is basically a large - fruited variety grown mostly in Central America. The fruit is a multi - seeded berry, pendulous or erect, and is usually borne singly at the nodes.

C. frutescens L. as a cultivated plant, the species in much less variable with a more restricted distribution than C. annuum . The variety Tabasco is the only cultivar grown in the United States. It is a short - lived perennial shrub. The corolla is greenish white, waxy, or shiny. The fruits are usually small and narrow, having green and yellow coloration when immature, turning red at maturity.

Capsicum baccatum L. is South American in origin and the widely cultivated variety is var. pendulum. Countries such as Argentina, Bolivia, Brazil, Chile, Ecuador, and Peru are known to cultivate this variety extensively (Pickersgill 1969 ).

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Capsicum chinense closely resembles C. frutescens but can be distinguished by the pedicels, which are usually shorter, thicker, and curved. It is commonly cultivated in South America and in the West Indies. The fruits are long and elongated and are red pinkish in color when mature.

Capsicum pubescens is a distinct species and can be distinguished from other cultivated species by pubescens, by its blue or purple fl owers. It is a high - altitude variety and is grown in countries such as Bolivia and Peru.

CULTIVATION AND CLIMATE

Chilis are grown in the tropics from sea levels to 2000 m or more. Generally, an optimum temperature of 24 ° C and at least 3 months of warm weather is required for good yields. The small fruits especially those of C. frutescens are much more tolerant to hot weather. An annual rainfall of 60 – 125 cm is required to grow chilis, and in India, the crops are grown throughout the year, excluding the period of January to March to avoid frosting. Well - drained heavy soil is preferred, loamy in nature, and the optimum soil pH is 6.0 – 6.5.

The crop may be sown directly in the fi eld as in the case of Southern United States, or a nursery is raised on seed beds and then transplanted into the fi eld. The usual spacing that is followed in between the rows is 60 cm, and about 17,500 plants could be accommodated per hectare. The usual spacing followed in India is 60 × 15 cm. The hot chili peppers are late maturing (100 – 115 days) compared to sweet pepper (58 – 82 days). The average yield of dry red chilis in a rain - fed crop in India is 280 kg/ha; however, the yields are largely variable depending on the fertility of the soil, agro - climatic conditions, and genetic lines.

HISTORY

Historically, the discovery of the American continent by Christopher Columbus is associated with the unraveling of peppers. It was popularly known by the famous quote “ Columbus never reached the spices of far East, he did fi nd one that has come to rival them. ” There is evidence that chilis were eaten by Indians perhaps as early as 7000 BC. Heiser (1969) says that the Indians were actually growing the plants between 5200 and 3400 BC. Chili comes from the dialects of Mexico and Central America. It is presumed that capsicum must have been taken by Columbus to Europe and has found its way to the Southeast Asian countries. C. annuum var. annuum and C. frutescens were spread to most of the warmer regions of the world, and the later species became naturalized in many tropical countries. India is the largest producer of chilis in the world, accounting for about 12 – 14 lakh tons of production annually, followed by China, with a production of about 4 lakh tons, Mexico with a production of 3 lakh tons, and Pakistan with 3 lakh tons. The extent of pungency depends on the cultivars, and some of the hottest chilis are grown in India. Varieties such as Bhut Jolokia and Naga Jolokia are very popular, and in terms of international pungency units known as Scoville heat units (SHUs), they are rated above 1,000,000 units . The extent of pungency in these cultivars is yet to be commercially exploited, as most of the Indian varieties that are commercially used have SHUs in the range of 10,000 – 20,000 units only.


DISEASES

Chili crops are susceptible to a number of diseases and the pathogens could be fungi, bacteria, or viruses. The damping of disease usually occurs in the nurseries due to infestation by Rhizoctonia solani (Kuhn) and Pithium sp. The seed may rot or the seedlings may be killed before emerging from the soil . The soft stems of young seedlings may also be attached after emergence, causing shriveling of the stems. Generally, captan is sprayed on the seeds or on the seed bed . Bacterial spot caused by Xanthomonas vesicatoria (Dows) can cause serious injury to capsicums, both on the leaves and on the fruits. The disease causes spots of yellowish - green color on the leaves and the severely spotted leaves turn yellow and brown. The bacteria are also soil borne and therefore crop rotation is of vital importance in avoiding the disease. Blight disease or root rot caused by Phytophthora capsici had also been described, and the symptoms include the appearance of dark, water - soaked patches on the fruit, which become coated with the growth of the fungus . Fusarium annum causes fusarial wilt characterized by drooping of lower leaves. The disease could attain highly damaging proportions for crops raised on poorly drained land and on temperatures above 27 ° C. Fruit rots caused by Colletotrichum capsici were also found to cause damage to the same extent as that of anthracnose caused by Gloeosporium piperatum . The curly top virus and also the tobacco mosaic virus cause immense damage in terms of the yield and quality of the crop. In addition to pathological diseases, a number of physiological disorders were also described causing blossom end rot and sunscald.

CHILI FLAVOR

Chili fl avors were characterized as a mixture of pyrazines, that is, 3 - isopropyl - 2 - methoxy pyrazine, 3 - butyl - 2 - methoxy pyrazine, and 3 - isobutyl 2 - methoxy pyrazine (Murray and Whitfi eld 1975 ). The pungency contributing principles are the capsa-icinoids, which are vanillylamides of various acids, out of which capsaicin as vanillyl amide of isodecanylic acid is the most important. Some of the most important capsicum - based fl avors are as follows:

Source: C. annuum L. Plant part: the ripe fruits The inner pericarp and seeds are removed, entirely or partly, when a less sharp

taste is desired. Components: A sharp - tasting capsaicinoid (0.3 – 0.5%), in addition to nordihydro -

and homodihydrocapsaicins, was found (Purseglove et al. 1981 ).

The main aroma constituent was described as 2 - methoxy - isobutylpyrazine (van Ruth and Roozen 1994 ). A steroid saponin mixture called capsicidin with capsioid was the main constituent, which functions antibacterially against yeast and fungi. The carotenoids, partly esterifi ed with fatty acids, mainly capsanthin, α - carotene, and violaxanthin, contribute toward the color. Apart from the organoleptic determina-tion of pungency (SHUs), the capsaicinoids are determined quantitatively with high - performance liquid chromatography (HPLC) (Kurian and Starks 2002 ). The

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quantitative determination of pellargonic acid and vanillylamide, which are avail-able synthetically and are therefore prone to adulteration, is of special importance. Red pepper and the corresponding oleoresins are used for coloring purposes. Methods for their quantitative determination are extensively researched to develop appropriate photometric methods after isolation by thin - layer chromatography (TLC) with simultaneous detection of synthetic dyes.

CHILIS (PEPPERONI)

C. frutescens is a major species being used for the extraction of pepperoni fl avor. Due to their higher capsaicinoid content, the fruits are considerably sharper in their pungency, and the basic constituents are the same as those of red pepper. Haymon and Aurand (1971) detected various esters of butyric, valerianic, and caprionic acids; however, no typical aroma constituents were detected.

The component in capsicum, which stimulated the valued pungency, was crystal-lized and named capsaicin by Thresh in 1946 . With the advancement in TLC, Kosuge and Inagaki (1959) showed that two related components are found in capsicum extracts, both of which stimulate pungency. They showed that the ratio of the two components did not vary with the variety they studied, the degree of maturity, and harvest, and the term “ capsaicinoids ” for the mixture of related components was proposed. Bennett and Kirby (1968) showed that crystalline isolates from capsicum extract contained two major components, capsaicin (69%) and dihydrocapsaicin (22%), and three minor related components; nordihydrocapsaicin (7%), homocap-saicin (1%), and homodihydrocapsaicin (1%) (Fig. 41.1 ).

Within the genus Capsicum , numerous species and varieties are cultivated and the highest level of pungency is associated with C. frutescens , whereas C. annuum comprises rather mild varieties (Jurenitsch et al. 1979 ). Yazawa and others (1989) reported the presence of capsaicinoid - like substances (CLSs) in a cultivar named CH - 19 Sweet of C. annuum . These CLS fractions have different resolution front (RF) values in TLC and are termed as CLS - A and CLS - B. Fraction A was known as capsiate and fraction B is known as dihydrocapsiate. Chemically, CLS - A was determined as 4 - hydroxy - 3 - methoxybenzyl (E - B - methyl - 6 - nonenoate), whereas CLS - B was found to be a 6, 7 - dihydro derivative of CLS - A (Kobata et al. 1998 ). The turnover of capsaicinoids during development, maturation, and senescence of chili peppers was related to peroxidase activity, and the content of capsaicinoids was found to decrease with an increase in peroxidase activity (Padilla and Yahia 1998 ). As such, the biosynthesis of capsaicinoids follows the cinnamic acid pathway, and the same had been described to occur in the placenta of the fruit (Fuzikawe et al. 1982 ). During the growth of chilis also, the turnover was found to be varied among different cultivars with a maximum buildup occurring at a specifi c stage of maturity followed by a decline (Iwai et al. 1979 ). Peroxidase causes the oxidative deterioration of capsaicin in the presence of hydrogen peroxide. Cellular disruption of C. annuum was found to result in signifi cant levels of oxidative deterioration. Kirschbaum - Titze and others (2002) noted that the size of capsicum segments infl uenced the deterioration , and halving was found to restrict the degradation compared to smaller precut slices. Maintenance of minced fruits under nitrogen atmosphere was found to stabilize the capsaicinoid content. The stability of


Capsaicin

Homocapsaicin II

Capsaicin

O

NH

HO

H3CO

O

NH

HO

H3CO Dihydrocapsaicin

O

NH

HO

H3CO Nordihydrocapsaicin

R groups:

(A) Branched, unsaturated

NH

HO

H3CO

O

RGeneral structure

Homocapsaicin I

(B) Branched, saturated

Nordihydrocapsaicin I

Nordihydrocapsaicin II

Dihydrocapsaicin

Homodihydrocapsaicin I

Homodihydrocapsaicin II

(C) Saturated, analogues

N-Vanillyl octanamide

N-Vanillyl nonanamide

N-Vanillyl decanamide

Figure 41.1. Pungent principles of chilis .

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capsaicinoids during processing, extractions, and storage of fl avor components is of critical importance in the commercialization of technologies concerning chili fl avor (Govindarajan 1986 ).

BIOSYNTHESIS

The biosynthesis of capsaicinoids coincides with the synthesis of lignin - like material, and the two are the major end products of phenyl propanoid metabolism. It was known that the synthesis of these products depends on the supply of intermediates, and a strong competition was observed between lignifi cation and capsaicinoid for-mation (Sukrasno and Yeoman 1993 ). Lignin formation could be linked with the development of seeds, and the capsaicinoids are synthesized in the placenta. The biosynthetic pathway of capsaicin follows a condensation process involving vanillyl amine and isocapryl – succinyl coenzyme A (SCoA) . Phenylalanine is the precursor for vanillyl amine with the formation of intermediates such as cinnamic acid and coumaric acid. The condensed product of valine and acetyl - CoA results in the for-mation of isocapryl - CoA, which further condenses with vaniline amine to form capsaicin (Fig. 41.2 ). Active accumulation of cinnamyl glycosides and fl avanoids both synthesized from phenylalanine before the onset of accumulation of capsa-icinoids was found consistent with phenylalanine ammonia lyase (PAL) activity (Yeoman et al. 1989 ). The cinnamyl glycosides undergo transformation, resulting in synthesis of capsaicinoids. Vanillic acid glycoside was found to be present in the fruits of C. frutescens with close proximity to capsicum present in the placenta. As such, the biosynthesis of capsaicin was known to be associated with the cinnamic acid pathway, and the networking encompasses the formation of lignin, fl avonoids, phenolic, and cinnamyl glycosides (Fig. 41.3 ).

EXTRACTION

Flavor extraction from different plant sources is an ever - evolving technology. Since fl avors constitute a vast commercial market and food fl avors are of the commodities industry, the cosmetic industry constitutes a highly competitive area of fl avor tech-nology . A food fl avor could render aroma as well as taste, and in the general sense, the aroma gains dominance over the taste part. Cosmetic fl avors form an amalgama-tion of trade formulations that are highly confi dential and branded. The food fl avors are open to a certain extent as the consumers need to know the nature of the fl avor as they identify the available fl avor with that of one which has a natural origin. Flavors could be of natural origin or synthetic in nature upon identifi cation of criti-cal chemical structures associated with natural fl avor. In the industrial production of natural fl avors, extraction plays an important role in obtaining the maximum recovery with minimal process losses of fl avor. The plant tissue needs to be disrupted by mechanical, thermal, or enzymatic methods to allow the extraction of the fl avor and aroma materials with high yields. The aroma materials as such could be distrib-uted throughout the plant material or they could be localized in specialized plant structures such as the oil sacs that hold mint oils present on the underside of the mint leaves. Plant cell walls are basically three layers: the middle lamellae and the primary and secondary cell walls. The middle lamellae bind the cells and are mostly


composed of pectin. The primary cell wall consists of cellulose fi ber together with pectin, hemicelluloses, and proteins. The secondary cell wall contains lignin and pectin. These cellular structures need to be disrupted to release fl avor and aroma chemicals contained with the cells. The enzymes commonly used in the manufacture of plant extracts include polygalacturonase, pectin or pectate lyases, esterases, cel-lulases, and hemicellulases.

The methods of fl avor production are mainly categorized into four types:

1. by direct extraction from the natural source, 2. by compounded fl avors as mixtures of chemically or naturally synthesized

fl avor molecules, 3. reaction fl avors by compounding appropriate precursor molecules, and 4. enzyme - or fermentation - linked production of fl avors.

OC

OH

COOH

Valine

Phenylalanine

Cinnamic acid

Coumaric acid

Caffeic acid

Ferulic acid

Vanillin

Vanillylamine

Capsaicin

Isocapryl-SCoA

3CH3COSCoAAcetylCoA

SC

oA

NH3

OC

OH

NH2

H2N

OC

OHHO

OC

OHHO

HOO

C

C

OHHO

OC

HHO

H3CO

H3CO

CH2 HO

H3CO

HO

O

C

O

HN

H3CO

Figure 41.2. Biosynthetic pathway of capsaicin.

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The direct extraction methods often include steam distillation and cold expres-sion, and the terminology adopted for the product depends on the nature of the extracts, that is, essential oil, absolute extract, resinoid, and oleoresins. The oleores-ins include many of the nonvolatile components that are otherwise not present in the corresponding essential oils. Capsicum fl avors include oleoresins as a major product. The compounded fl avors require a precise chemical analysis for synthesiz-ing similar compounds followed by formulation as a fully compounded or semi - compounded product. Maillard reaction products are the major reaction fl avors using sugars and amino acid sources besides sulfur - containing compounds followed by heating to accelerate the chemical reaction. The enzyme or fermentation - based reactions could be expensive initially, but the prices do get stabilized due to the emergence of demands.

Phenyl alanine

Cinnamic acid

ρ-Coumaric acid

Caffeic acid

Ferulic acid

Vanillin

Vanillylamine

Capsaicinoids

Cinnamoyl glycosides

Lignin

Flavonoids

C6 –C1 phenolic glycosides

Figure 41.3. Biosynthetic relationship between phenolic compounds and capsaicinoids.


The directly extracted fl avors offer a range of technological feasibility, and capsicum fl avors could be cost effectively extracted using the standard procedures (Fig. 41.4 ).

The range of directly extracted fl avors includes a variety of entrapment methods meant for extraction of exudates giving rise to resinoid, formation of concretes by nonpolar extraction, absorption into fat known as enfl urage , or ethanol extractions to form tinchers. A newer method of fl avor extraction aims at fl avors drawn from glycosidic molecules (Spanier 1993 ).

EXTRACTION METHODOLOGIES

Solid – Liquid Extraction

The principle of solid – liquid extraction consists of adding liquid solvent to a solid matrix in order to selectively dissolve and remove the solute. The chosen extractants must be capable of preferentially dissolving the compound to be extracted. Solid – liquid extraction methods are applied to the industrial scale in the fl avor industry apart from oils and fats. Red pepper is largely subjected to solid – liquid extraction methods apart from pepper, mint, vanilla, and licorice. The major characteristic of solid – liquid extraction lies in the fact that there is no defi ned distribution coeffi cient for the distribution of solutes in extracts and feeds (Gnayfeed et al. 2001 ). The equilibrium is never reached practically as the solid matrix still contains bound solute in the capillaries. It is advisable to carry out the practical measurement of moisture content, reduction ratio, and type and amount of solvent to be used to optimize the process. The polarity of the solvent also plays an important role in optimizing the extraction procedures.

Maceration Maceration is usually carried out by crushing, grinding, or cutting procedures. Maceration can be improved by agitating the extraction material with

Plant material

Traditional extraction methods Modern extraction methods

Grinding Steam distillation Liquid CO2 extraction Use of enzymes

Extracts

Concentration, addition of other materials/formulations

Heat treatment and formation of reaction flavors

Fermentation and/or enzyme treatment

Figure 41.4. General methods of fl avor production.

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mixtures, stirring devices, or homogenizers. The Use of acoustic waves also plays an important role, and a range between 25 and 1000 kHz has been found to be highly supportive in these aspects (Ziegler and Ziegler 1998 ). Similarly, electrical dis-charges with a broad frequency can be helpful in improving extraction. Changes in temperature and pH can also have an impact on the yield and quality of the extract.

Counter and Current Extraction The process is called percolation if the solid matrix is repeatedly extracted with fresh solvent. This process could be used for laboratory or industrial purposes. In the laboratory, the process could be carried out with Soxhlet extraction. Kurian and Starks (2002) developed single - stage quantita-tive extraction procedures for the extraction of capsaicin in dried and moist forms for HPLC analyses, which do not require extensive cleanup as compared to other methods. The countercurrent extraction could be continuous, discontinuous, or of absolute countercurrent methods. The differences in the extraction procedures depend on the movement of the solvent and the feed in terms of direction and mode of solvent application.

Liquid – Liquid Extraction

Liquid extraction is an important separation technique for laboratory use during which the aromatic compounds are obtained with glycolin and sulfolane. The prin-ciple of liquid – liquid extraction involves adding of liquid solvents to a mixture in order to selectively remove components by the formation of two immiscible liquid phases. The selected solvent shall be capable of preferentially dissolving the con-stituents to be extracted besides being immiscible or at least partially miscible to facilitate separation of layers subsequently. A number of factors including polarity and dielectric constants of the solvents play an important role in selecting appropri-ate solvents to optimize the process (Wooderck et al. 1994 ). The process could be single - or multistage extractions in continuous or discontinuous modes. The process could be limited to either single or multistage procedures. The equipment required for such extractions include a variety of extractions such as centrifugal extractors, extraction towers, mechanical agitators, and others.

Supercritical Fluid Extraction

Selection of solvents depends on a number of factors in conventional solvent extrac-tion procedures, such as evaporation enthalpy – selectivity, specifi c heat capacity, combustibility – stability, fl ash point – reactivity, explosion limits – viscosity, maximum allowable working concentration – surface tension, and environmental relevance – boiling point .

The constraints are too many to select the appropriate solvent, and an ideal solvent meeting all the requirements besides the safety features is still at large. Another limitation of conventional solvent extraction is the formation of by - products, which have toxicological implications besides causing environmental hazards (Gnayfeed et al. 2001 ). These limitations lead to the invention in terms of use of gas - based solvents in a near - critical state. Supercritical fl uid extraction, also referred to as dense gas extraction or near - critical solvent extraction, denotes the operational temperature of the process to be close to the critical temperature of the


solvent. Since the extraction of herbal raw materials requires nondrastic, gentle process temperatures, the choice of suitable near - critical solvents is limited to pure or partly halogenated C 1 – C 3 hydrocarbons and carbon dioxide. Carbon dioxide is the most favored supercritical fl uid extraction medium due to many reasons, such as adjustable selectivity, low dissolving power, high diffusion rates, low viscosity, exclusion of oxygen, restricted thermal stress, no solvent residues, easy solvent recycling, stable and inert behavior, and its being bacteriostatic, nonfl ammable, inexpensive, and environmentally safe (Tipsrisukond et al. 1998 ).

SALIENT FEATURES OF CO 2 EXTRACTION

CO 2 extracts are by nature lipophilic products. A number of volatile fractions, that is, monoterpines, phenyl propane derivatives, and sesqueterpines and oxygenated molecules like ethers, esters, ketones, lactones, and alcohols, are easily soluble, and all of them are typical components of essential oils. The solubility decreases with an increase in molecular weight and polarity. Therefore, oils, resins, steroids, alkaloids, carotenoids, and oligomers are less soluble. Supercritical carbon dioxide (SC CO 2 ) offers the possibility to change the solvent power within a wide range by adjusting the gas density. Liquifi ed CO 2 , in contrast, is more similar to normal solvents without the possibility to infl uence the dissolving power. Gnayfeed and others (2001) described SC CO 2 - based extraction of ground paprika ( C. annuum L.) and also subcritical propane at different conditions of pressure and temperature to estimate the yield and variation in carotenoids, tocopherols, and capsaicinoid contents and composition. The yield of paprika extract was affected by the extraction condition with SC CO 2 compared to subcritical propane. A maximum yield of oleoresin at 7.9% was reported. However, SC CO 2 was found suboptimal in the extraction of diesters of xanthophylls even at 400 bar and at 55 ° C. On the other hand, tocopherols and capsaicinoids were easy to extract at these conditions. A number of workers reported SC CO 2 as an effective mechanism to extract the pungent principles from spice paprika. Coenen and Kriegel (1983) described the use of supercritical gases on commodities such as spice paprika. Knez and others (1991) and Knez and Skerget (1994) highlight SC CO 2 as an effective extraction medium for capsicum fl avors. Coenen and Hagen (1983) found SC CO 2 an effective solvent for the extraction of natural colorant from paprika. The paprika extracts with SC CO 2 were light red to red in color, and the extraction pressures from 200 to 400 bars showed positive correlation with the rate and yield of extraction along with the density of the extraction medium. The impact of extraction conditions on the solubilization of oleoresins from pungent paprika by SC CO 2 was similar to that noticed with non - pungent paprika (Illes et al. 1997 ). Galan - Jaren and others (1999) reported that oil and pigment extraction by SC CO 2 is pressure dependent. Skerget and Knez (1997) described the relative solubilities of β - carotene and capsaicin in high - density CO 2 on the basis of capsaicinoids extracted from a known quality of powder; the recovery of these compounds to signifi cant levels could be achieved at 400 - bar pres-sure at 55 ° C. However, the use of modifi ers could not substantially increase the recovery of capsaicin (Yao et al. 1994 ). The other reports on capsaicin extraction from red peppers also describe SC CO 2 as an effective extraction medium (Yasumoto et al. 1994 ).

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The extraction of capsaicin with SC CO 2 laid emphasis on relative solubilities of β - carotene and capsaicin, and model systems were worked out as binary or tertiary models. The data on binary systems were vast (Sakaki 1992 ). However, as a tertiary system with dense CO 2 as a component of the system and in comparison with liquid and supercritical forms, the results were highly interesting due to the establishment of equilibrium solubilities (Skerget and Knez 1997 ; Skerget et al. 1995 ). The extrac-tion of paprika with organic solvents was known to cause some disadvantages causing extract denaturation. The process for production of paprika oleoresin has been described by many workers (Coenen et al. 1983 ). The various extraction models with regard to relative solubilities in SC CO 2 could be optimized with better recovery profi les and associated advantages with the addition of polar co - solvents such as 2 - 3, dimethyl phenolphthalein, and phenanthrine as described by Dobbs and others (1987) .

QUANTIFICATION OF PUNGENCY

Pungency of chili fl avors is an inseparable attribute that needs authentic quantifi ca-tion to determine the quality of the product. The nature of the pungency stimuli is extensively researched by Suzuki and Iwai (1984) . The fl avor profi les depend largely on the species as well as on varietal differences. In the case of C. annuum var. annuum , dihydrocapsaicin and capsaicin dominate the fl avor, whereas nordihydro-capsaicin plays a secondary role toward the overall contribution to pungency. In the case of C. frutescens , the overall pungency is largely dominated by capsaicin alone with dihydrocapsaicin getting restricted to a secondary role in order to regulate the fl avor profi les. Process optimization during extraction and also prevention of pos-sible adulteration in authentic quantifi cation schedule are highly essential. It is also known for a long time that synthetic nonoylvanylamide could be found in varying extents in commercial oleoresins from chilis. Therefore, it is highly essential to determine the upper limits of the natural occurrence of straight - chain analogues to determine the extent and type of adulteration.

ANALYTICAL METHODOLOGIES

The methods include subjective as well as objective methods. The subjective meth-odologies are time tested, and chili pungency is still widely reported as SHUs.

Scoville Test

Scoville test for chili fl avor was reported by Scoville (1912) . The subjective method was adopted and modifi ed by American Spice Trade Association (ASTA 1968 ) and by the International Organization for Standardization (ISO 1983 ). In the Scoville test, samples were extracted as per the standard procedure described by ASTA methodology (21.0). In the sensory evaluation for pungency, six panelists could be used, three male and three female within the age group of 21 – 30 years, who were trained in pepper pungency evaluation trials. The tasters need to continue through a sequence of dilutions until a defi nite sensation was noted. The heat units for the


solutions for which the fi rst three of the fi ve panelists reported positive values are recorded. During the course of time, SHU testing underwent a series of changes. One of the foremost among them had been the conversion of objectively estimated capsaicinoid concentrations by making use of a coeffi cient for each compound (Todd et al. 1977 ). The coeffi cients reported were 16.1 for capsaicin and dehydro-capsaicin and 9.3 for nordihydrocapsaicin.

Gillette Method

Another popular method for subjective evaluation is the Gillette method. Although this method is not as popular as the Scoville test, positive correlations were obtained highlighting the usefulness of the test (Quinones - Seglie et al. 1989 ). In the Gillette test, a partially balanced incomplete block design could be used with four different samples per session amounting to nine sessions and four replications as such. The panelists score the samples on an intensity scale of 1 – 9 from no heat to extremely hot. The methodology as such involves dissolving 50 g of freeze - dried ground cap-sicum in 199.5 g of commercially available springwater at 90 ° C followed by extrac-tion for 20 min. The extraction is followed by fi ltration with subsequent dilution in springwater to 10 - fold. The testing procedure involves clearing of the mouth with springwater at 20 ° C. The samples are swallowed slowly and after 30 s are rated on the ballet followed by clearance of mouth with springwater at 20 ° C. Unsalted crackers are used for mouth clearance for 60 s followed by rinsing with springwater at 20 ° C.

LIMITATIONS OF SUBJECTIVE METHODS

The Scoville test method had been severely criticized but continues to be employed as an authentic method for capsicum pungency (Maga 1977 ; Suzuki et al. 1980 ). The specifi c problems associated with the Scoville test are buildup of heat, rapid test fatigue, ethanol bite, lack of statistical validity, lack of reference standards, a long extraction time of 16 h and poor reproducibility.

The Gillette method was considered by ASTM (ISO 1983 ) as the method that could restrict problems such as high taste fatigue and heat buildup. The increased threshold is accounted for by the use of standardized initial samples as well as a time - related rise between the samples. The extraction time is reduced from 16 h to 20 min in the Gillette method, and ethanol bite is avoided by the use of aqueous extraction.

OBJECTIVE METHODS

The objective methods could be grouped into four types depending on the cleanup and instrumental procedures as well as the involvement of chromogenic reactions or the use of chromatographic methods:

1. chromogenic reagents reacting with the phenolic hydroxyl group of the vanil-lyl fraction in the extracts;

CHILI FLAVOR 789

2. removal of interference by natural pigments, that is, carotenoids, by a cleanup step before using chromogenic reagents;

3. improved chromatography cleanup and use of specifi c chromogenic or spec-trophotometric measurement for the development of micro methods; and

4. use of HPLC methods for the separation of individual capsaicinoids.

The earlier methods included chromogenic reactions from crude extracts using vanidiumoxytrichloride or ammonium vanadate and hydrochloric acid to react with the phenolic hydroxyl group of the vannyl amide followed by measurement of the blue color. The presence of natural colors within the extract was compensated by use of natural carotenoids, synthetic colors, or inorganic mixtures of cupric nitrate and potassium dichromate (Suzuchi et al. 1957 ).

Kosuge and Inagaki (1959) determined capsaicinoids in ether - extracted concen-trates taken in carbon tetrachloride, washed with acetic acid, and reacted with Folin – Ciocalteu reagent. The blue color was measured at 750 nm and was quantifi ed using pure vanillin as standard and a factor of 2.15 to obtain capsaicinoid content. Though the method appears to yield very good results, a large number of determina-tions are required in breeding and selection programs .

METHODS BASED ON SEPARATION

Solvent Partition

Capsaicinoids could be separated from pigments by repeated partitioning between alkaline polar and nonpolar solvents. The capsaicinoids with only a trace of color and fat are estimated by reacting with phenolic reagents, that is, phosphomolybdic or phosphotungstic reagents followed by measurement of the blue color at 725 nm. Tirimanna (1972) used a more elaborated purifi cation procedure with similar solvent partitioning to remove pigments and capsaicinoid phenolics by the judicious use of TLC methods .

Column Separation

Charcoal or alumina columns are widely used for absorption and elution of capsa-icinoids. The purifi ed capsaicinoids were quantifi ed using crystalline capsaicinoids as standard by colorimetry involving reaction with diazobenzene sulfonic acid (Brawer and Schoen 1963 ). The column separation involved extraction followed by separation, elution, and measurement.

A joint committee (Anon. 1959 ) on methods for assay of crude drugs in the United Kingdom surveyed the methods and selected two methods for capsaicinoid separation:

1. acidic alumina column and illusion with absolute methanol and 2. ether - alkali partitioning extraction and quantifi cation by spectrophotometric

or colorimetric methods.

The recommendation also includes the use of diazo color reagents with Gibbs phenol reagent (2, 6 - dichloro parabenzoquinone - 4 - chlorimine).


Chromatographic Micro Methods

This layer chromatography could give a new dimension in the separation and quan-tifi cation of capsaicinoids. Dohman (1965) described a comprehensive method by TLC for the separation of capsaicinoids from the chloroform extracts of spice cap-sicum on silica gel G plates along with standard capsaicinoids. The plate is developed with chloroform – methanol – acetic acid (95:5:1 v/v/v) to a distance of 14 cm. The bands are marked as dark areas under UV light. The separated bands of capsa-icinoids are detected with Folin – Denis reagent, and the capsaicinoid concentration is calculated spectrophotometrically at 725 nm.

Capsicum fruits in the maturing green stages are used regularly in the growing countries for making certain types of sauces and chutneys. There is also a growing report of green paprika stimulating mild pungency. These require a rapid quality control protocol for pungency evaluation. Isopropanol extracts of ground fresh capsicum fruit are treated with carbon to remove color then concentrated under vacuum and low temperature. The residue is dissolved in isopropanol to defi nite volume and absorption measured at 280 nm and quantifi ed with respective pure capsaicinoid as reference (Gonzalez and Altamirano 1973 ).

Nagin and Govindarajan (1985) found acetone extraction of capsicum fruits resulting in poor extraction and mashy layer formation. Careful sun - drying of cut sections of green fruits to about 10% moisture allowed grinding of the samples and clean solvent extraction.

Gas chromatographic analysis of capsaicinoids also received major attention. Muller - Stock and others (1971) used 1% or 3% JXR on a Gaschrome Q (100 – 200 mesh) column using a linear temperature program run at 150 – 230 ° C at 6 ° C/min. The components were identifi ed by a combined mass spectrophotometer and were quantifi ed by an automated area integrator. The peak profi le included a minor peak for nordihydrocapsaicin, a dominant peak for capsaicin, and an overlapping but distinct peak of dihydrocapsaicin.

Comprehensive literature exists with regard to the percentage of capsaicinoid component with emphasis on capsaicin, dihydrocapsaicin, nordihydrocapsaicin, homodihydrocapsaicin , and octanyl vanillylamide in cultivars of C. annuum , C. frutescens , C. baccatum and C. pubescens (Govindarajan et al. 1986 ). The ratio of capsaicin to dihydrocapsaicin had been considered as characteristic of the species, variable but generally about 1:1 for C. annuum , 2:1 for C. frutescens and C. baccatum , and 0.7:1.0 for C. pubescens .

Modern HPLC technique dominated the scenario due to superior separation capabilities for closely related compounds, and the separation could be carried out at room temperature. Maillard and others (1997) reported a comprehensive account of 11 capsaicinoids by reversed - phase HPLC. More than 90 different capsicum varieties were evaluated using C - 18 Hypersyl column eluted with ethanol – water – acetic acid (60:39:1 v/v/v). The maximum capsaicinoid content was reported for C. frutescens followed by C. pubescens , C. baccatum , and C. annuum . The fractions were coupled with nuclear magnetic resonance (NMR) analysis confi rming the structural aspects of already known capsaicinoids. It was found that all the characterized cap-saicinoid compounds possess a vanylamide structure and that the major differences were found to be in the alkanyl or alkanyl radicals of the acidic part of the molecule. The method was also applied to commercial oleoresins of capsicum, that is, cayenne

CHILI FLAVOR 791

pepper and C. frutescens . The oleoresins were found to have equal amounts of capsaicin and dihydrocapsaicin (35%), and other components were found to be nordihydrocapsaicin (11.7% in C. frutescens and 8.4% in cayenne pepper) followed by octanyl vanyl amide (4 – 5%) and nonanylvanyl amide (4 – 5%).

Kurian and Starks (2002) described the HPLC separation of capsaicinoids from whole orange Habanero chili peppers. C. chinense (orange Habanero) pepper samples were analyzed, and capsaicin to an extent of 1250 ppm and dihydrocapsaicin to an extent of 540 ppm were reported on a fresh weight basis.

The above described analytical methods are extremely important in breeding and selection procedures to develop improved germplasm besides their role in quality control and inspection regimes of peppers and their oleoresins.

QUALITY OF CHILI FLAVORS

The quality of chili fl avor has a lot to do with the principle of pungency alone. However, a number of other quality attributes such as size, shape, color, and fi rmness play an important role. Chili fl avor, however, is linked with pungency; the fl avor profi le includes the aroma apart from the taste. Pungency is basically a mouthfeel, besides which also contributes to a strong aroma sensation. Weisenfelder and others (1978) gave a comprehensive account inclusive of subjective and objective quality attributes of jalape ñ o chilis. The authors reported a poor correlation between the total capsaicinoid content and pungency as such, and the capsaicinoid content covered a range of 0.60 – 1.65 mg/100 g. The correlations of sensory evalua-tion with instrumental measurement probably became fl awed due to poorly defi ned scale descriptions and details of evaluation resulting in confused evaluation patterns .

The pungency testing by subjective means need to be defi ned appropriately in terms of direct biting, dilution to use level, or by threshold test. Direct testing may overpower the taste perception. On the other hand, aroma needs to be discriminated by comminution and sniffi ng under standard conditions. Determination of threshold pungency levels for optimal fl avor evaluation received widespread acceptability. Rajpoot and Govindarajan (1981) reported sensory methodology using a pungency detection scale of 1 – 6 where a rating of 1 represents “ defi nitely not detectable ” and 6 represents “ defi nitely detectable. ” The authors also recorded that Scoville value was not infl uenced by the interstimulus duration from 20 s to 4 min. The sugar con-centration of the dilution medium ranged from 0% to 10%, and the swallow volumes varied from 2.5 to 10.0 mL. Suzuchi and others (1957) showed that 3% solution in place of 5% interferes less with detection and recognition of pungency. The method described by Gemert and others (1983) could be applied to chili oleoresins using the usual threshold experiment, which showed high correlation with total capsa-icinoid content. Figen and others (2002) gave regression coeffi cient - based conver-sion formulae for the calculation of Scoville scores from capsaicinoid contents:

Scoville score capsaicin level mg g= × ( ) +76 8 100 2691 0. , . ,

Scoville score dihydrocapsaicin level mg g= × ( ) +88 2 100 3453. , .66, and

Scoville score total capsaicinoid level mg g= × ( ) +42 7 100 293. , 55 1. .


The regression coeffi cients for capsaicin, dihydrocapsaicin, and total capsaicinoid levels against Scoville scores were found to be 0.89, 0.85, and 0.91, respectively. An electronic nose was used to discriminate ground red pepper samples by headspace volatiles. The classifi cation of ratings was carried out based on the electronic nose data for grouping.

The chances of fl avor adulteration in case of oleoresins are high enough due to the availability of several capsaicin homologues and analogues. Todd and others (1977) described fi ne capsaicin homologues by synthesis under optimized conditions of trimethyl silylation, and all the fi ne homologues showed high correlation with pungency levels. These synthetic vanylamides could be separated by column chro-matography and could be identifi ed by gas or liquid chromatographic methods. The quality control methodology of capsicums shall include authentic quantifi cation of pungency in fruits as such or in the oleoresins concerned. In the case of whole cap-sicums in fresh or dry forms and also in dry and powdered forms, the other quality attributes such as color, shape, size, and insoluble ash play an important role. Detection and quantifi cation of adulterants is of major concern in powdered chilis and oleoresins in particular. The use of Sudan colors is of common occurrence apart from the use of fi llers such as saw dust and wheat fl our (Table 41.2 ).

U . S . STANDARDS FOR OLEORESIN CAPSICUM (AFRICAN CHILIES) ( EOA NO. 244)

The product is obtained by the solvent extraction of the dried ripe fruits of C. fru-tescens L. or of C. annuum L. var. conoides Irish (a form of C. frutescens ), with the subsequent removal of the solvent. The physical and chemical constants are speci-fi ed as follows:

TABLE 41.2. Requirements of the U . S . Government Standards

Characteristic

Percentage on Material as Received

Paprika Red Pepper Chili Pepper

Moisture, not more than 12.0 10.0 — Total ash, not more than 8.5 8.0 — Acid insoluble ash, not more than 1.0 1.0 — Extractable color (expressed as

ASTA color units), not less than 110.0 — 70.0

Scoville pungency (expressed as pungency rating units)

— 30,000 – 55,000 —

Sieve test U.S. standard sieve size No. 30 No. 4, no. 8, no. 20 — Percent by weight required to pass

through, not less than 95 95 85 — —

Percent by weight retained, not less than

— — — 95 —

Source : U.S. Federal Specifi cations: spices, ground and whole, and spice blends, No EE - S - 63H, June 5, 1975.

CHILI FLAVOR 793

Appearance and odor: A clear red, light amber, or dark red, somewhat viscid liquid with characteristic odor and very high bite

Scoville heat units: 480,000 minimum Color value: 4000 maximum Residual solvent in

oleoresin: Meets with the Federal Food, Drug, and Cosmetic

Act regulations Descriptive characteristic

solubility: Alcohol: partly soluble with oily separation and/or

sediment. Benzyl benzoate: soluble in all proportions. Fixed oils: soluble in all proportions in most fi xed oils Glycerin: insoluble Mineral oil: insoluble Propylene glycol: insoluble

FOOD APPLICATIONS

Chilis in fresh, dried, powdered, or paste forms are widely used in various food preparations including fermented foods, meat, cereal, millet, and vegetable products. The product range includes sauces, chutneys, culinary pastes, pickles, fermented beverages, and snack foods. The use of chilis could be to impart pungency, color, aroma, and aesthetic value as such due to the garnishing quality. The use of chilis depends on the geographic locations of the country concerned, which infl uences food habits and also cultural identity. India, Sri Lanka, Bangladesh, Pakistan, Nepal, and Bhutan use chilis to a greater extent. Some of the most pungent chilis are grown in Bhutan, in the northeastern states of India, and in Sri Lanka (Govindarajan et al. 1986 ). Dried red chili powder from C. frutescens is a major spice product, and the oleoresin extraction is a restricted practice.

ADVANTAGES OF CAPSICUM OLEORESINS

Oleoresins have many advantages over ground spices as fl avor additives due to elimination of microbial contamination, uniformity of color and fl avor strength, and optimal utilization. Usually, capsicum oleoresins are tailored to specifi c uses in terms of total color, pungency, and miscibility in oil or aqueous media. The ground spice equivalent of the oleoresins determined by sensory testing is also given as a guide. The use of chili oleoresins is relatively small and the products are gaining popularity over the years. Ground capsicums, due to their particulate nature, tend to render bursts of pungency when they come under the teeth compared to the uniform pun-gency of oleoresins throughout the mastication (Kirschbaum - Titze et al. 2002 ). It depends on the consumer taste in appropriating the relative use of ground capsicum and oleoresin. Perhaps the product nature is of crucial importance in deciding the choice. Salads, pickles, and Latin American recipes and also the Indian subcontinen-tal recipes may prefer ground capsicum. However, sauces, meat preparations, certain types of fl avored cheese, curry mixes, vegetable pastes, and sour beverages may be more compatible to the use of chili oleoresin.


Chili fl avors come under the class of pungent and hot fl avors, and other fl avors in the same category are ginger, horseradish, mustard, and pepper. Table 41.3 shows the classifi cation of herbs and spices by sensory characteristics.

USE OF CHILI FLAVORS IN VARIOUS ETHNIC FOOD PREPARATIONS

Chili fl avor or ground capsicum as such is preferred in hot and pungent food prod-ucts, and the countries include the Indian subcontinent, Latin American countries, oriental countries, China, Southeast Asian countries, Middle East, and the Central African countries. The products include meat and baked foods, soups, curries, gravies, seafoods, fermented foods, and beverages. Kimchi is a popular oriental fermented food and the pungency factor is an important quality aspect. Irradiated red pepper powder was widely reported to render optimal sensory quality without causing microbial contaminations (Lee 2004 ). Irradiation was found to cause certain varia-tions in the volatiles involving formation of butyl benzene derivatives, which is not desirable (Lee et al. 2004 ). Therefore, the use of oleoresins derived from capsicum and colorant in the form of paprika with residual fl avor has an increasing commer-cial utility in the preparation of several products including kimchi and sauerkraut. Acuka sauce, a famous Turkish product, makes use of hazelnut and pepper paste (Ozcan 2002 ). The product could be an ideal one for the use of chili oleoresins as ground pepper paste could make the texture susceptible besides hindering the spreadability of the product. Kochuzang is another important traditional orien-tal product. It is available in sweet or savory taste. The commercial product is basically a decomposed product fortifi ed with fl avor, and chili fl avor could be an appropriate substitute for ground chilis traditionally used in fl avoring the product (Park et al. 2003 ).

TABLE 41.3. Classifi cation of Herbs and Spices by Sensory Characteristics

Red pepper, fresh (1000) Curry powder, blend (260) Cayenne pepper, dried (900) Mustard seed, dried (240) Horseradish, fresh (800) Coriander seed (230) Mustard powder (800) Turmeric, fresh (220) Pickling spice, dried (700) Turmeric, dried (200) Clove, dried (600) Peppermint, dried (150) Garlic fresh (500) Cardamom, dried (125) Bay leaf, dried (500) Spearmint, dried (100) Ginger, dried (475) Poppy seed, dried (90) Black pepper, dried (450) Thyme, dried (85) Cinnamon, dried (400) Parsley, dried (75) Onion, fresh (390) Sweet basil, dried (70) Mace, dried (340) Onion, dried (60) Celery seed, dried (300) Paprika, dried (50) Cumin seed (290) Saffron, dried (40) Fennel seed, dried (280) Sesame seed, dried (25)

CHILI FLAVOR 795

The Indian culinary makes use of ground chilis, chili paste, and precut green chilis as a major source of pungent fl avoring. The products are formulated in the form of vegetable, meat, poultry, and seafood - based curries, chutneys, pickles, and sauces. The traditional use of chilis tends to pose a number of problems with regard to microbial spoilage, and the fungal spores could be a major source of concern. Most of these products are thermally processed to varying extents, and the pasteurized products depend on rendering medium to high acid levels to the product to ensure food safety. The lack of commercial sterilization in these products causes a latent incidence of fungal spores as in the case of ketchups, stabilized chutneys, and other products. Chilis could be a major source of spore contamination in these products and in precut green chilis; the acidic pH tends to discolor the chilis, which is not desirable in terms of color attributes. The use of chili oleoresins in some of these products could be benefi cial in restricting the latent infections, which otherwise may cause health hazards.

The Middle East countries use a number of chili - fl avored products including meat and baked products apart from soups, sauces, and juice cocktails. Chilis and extracts of tejpat ( Cinnamomum tamala ) are widely used in these preparations apart from black pepper. Salami preparations, sausages, and minced meat preparations such as barbecues, meat and fi sh tikkas , kababs , and patties require pungent fl avor in abundance, and ground spice - based masalas are widely used across these coun-tries (Coon 2003 ). Chili oleoresins are suitable for these products due to their uniform pungency and ready miscibility with oil or aqueous media. Certain wines are also used, which could be fl avored with chili or pepper oleoresins. The popularity of health drinks based on vegetable and herbs is on the increase including Aloe vera - based products. These beverages are usually prepared in salted or spiced forms to restrict the calorie output, which otherwise has to depend on nonnutritive sweet-eners. Chili oleoresins could be used on unsaponifi ed or saponifi ed extracts of red pepper depending on the nature of the product. Some products could be suitable for the use of paprika extract, such as fried boiled eggs or meat preparations, and the residual pungency fl avor meets the fl avor requirements where color quality is predominant rather than the pungency level of the extracts . Several cereal - based products such as biryanies could be subjected to the use of chili oleoresins or paprika extracts. Among the baked or extruded products, cookies and crunchy extruded products are the ideal ones for the application of chili fl avors to enhance the sensory attributes.

Among the popular Middle East recipes, kibbeh is one of the most sought after products. Kibbeh is a dish made with lamb meat or beef along with cracked wheat and pine nuts. The dish is popular in Lebanon, Israel, and Syria. It can be eaten in fried or baked form. Chilis, along with cumin and cinnamon, are used as spices in the preparation of the dish, and chili oleoresins could be used to render uniform pun-gency within the product. Other meat dishes such as sambaosak , lamb shishlik , and al - motubug could also be spiced with chili fl avor or chili oleoresins. As such, the Middle East cuisine includes a number of spices including chilis. Historically, Middle East was either the source or the transit point for spice trade between Asia to Europe. Middle Eastern foods are usually eaten with “ pita bread, ” and moderate pungency levels in the various foods, either meat based or salads, are preferred (Giese 1994 ). Chili oleoresins could play a major role in meeting these requirements.


SAFETY OF CHILI FLAVORS

Flavors in general represent a class of food additives with comparatively less legisla-tion. This is probably due to the relatively large number of ingredients used in fl a-vorings, the very small quantities involved, and the diffi culty involved in regulating added substances . The legislation includes positive and negative approaches with the positive list including permitted fl avor agents and the negative list including nonpermissible substances. The Generally Recognized as Safe (GRAS) list of the Food and Drug Administration (FDA) and the Flavor and Extract Manufacturing Association (FEMA) complement each other in regulating fl avors in the United States. The Joint Expert Committee on Food Additives (JECFA) as a nodal orga-nization for Codex Alimentarius has evaluated around 300 fl avoring substances (Munro et al. 1999 ). The Council of Europe Expert Committee (CEEC) laid down certain guidelines (Council of Europe 1995 ) to regulate the production of processed fl avorings, ingredients, and process conditions. The guidelines include various aspects, such as ingredients added prior to processing, ingredients added after processing, process conditions, purity criteria, and safety evaluation.

In the case of chili fl avors, adulteration with synthetic analogues is one of the major problems, and appropriate analytical techniques were described to identify the adulteration. The physiological, pharmacological, and toxicological aspects of capsaicin were described in detail by Kati - Coulibaly and others (1998) . The LC 50 and LD 50 tests in toxicological experiments using capsaicin at various doses showed lung, thorax, skin, as well as seizers as the observable effects when the feeding is carried out by different modes such as inhalation and oral or intraperitoneal appli-cations. However, the doses are high ranging from 0.25 to 10.0 g/kg body weight.

GENETICALLY MODIFIED CHILI

The genetic modifi cations in capsicums, as such, are to improve disease resistance of capsicum plants as the crops are highly susceptible to insects and to bacterial or fungal attacks. The other approach is to make the crop tolerant to temperate condi-tions and also to induce osmotolerance and cold adaptations. Being a member of the Solanaceae family, the crop is highly conducive for genetic manifestations. Yamakawa and others (1998) described the transformation of chili pepper with the PAL gene, which has ramifi cations in terms of disease resistance as well as biosyn-thesis of capsaicinoids. However, efforts were made to increase the capsaicin content by biotechnological methods. Sudhakar - Johnson and Ravishankar (1998) described a biotransformation method to regulate the capsaicinoid pathway to result in enhanced yields of capsaicin. Immobilized placental tissues of capsicum frutescence were treated with L - phenylalanine, cinnamic acid, coumaric acid, caffeic acid, ferulic acid, and vanyl amine in combination with L - valine to obtain promotive effects on capsaicinoid yield. However, it is pertinent to note that climatic conditions also show signifi cant effects on capsaicinoid yield (Harvell and Bosland 1997 ). The genetic control of pungency in C. chinense was reported through the Pun1 locus and modi-fi cation of the same was found to result in modifi cations in the pungency levels (Stewart et al. 2007 ). The future areas of research in genetic modifi cations of capsi-cums include regulation of capsaicin content and also the sweeter varieties in terms

CHILI FLAVOR 797

of improvement in palatability. The chili oleoresin - , paprika - , and condiment - based industries would like to make full use of these improved varieties. Colored and sweet capsicums, on the other hand, form an important aspect of marketing for salads, and they would also be benefi cial for the improvements in the germplasm of capsicums .

CONCLUSION

The botanical and agronomic aspects of chilis and the geographic distribution of different chili varieties and cultivars enable appreciation toward the novelties of different cultivars grown in different agro - climatic zones. Extraction, isolation, and characterization of capsaicinoids are ultimately directed toward the development of highly sensitive analytical methods. The chemistry and biosynthetic pathway gives a comprehensive account of the various intricacies in the development of pungency within chilis. The industrial methods of extraction such as SC CO 2 extraction methods need to be applied to a greater extent to improve the production and trade concerned with chili fl avors, that is, chili oleoresins. The correlations drawn between the subjec-tive and objective methodologies make it possible to draw conversion equations for the benefi t of quality control procedures. The subjective methods such as Scoville heat testing have specifi c sensory evaluation protocols, and the latest modifi cations could be helpful in improving the dependability of such tests. The HPLC method-ologies provide a greater degree of safety consciousness to detect use of synthetic analogues in the quality control regimes. The toxicological aspects highlight the necessity to adopt appropriate allowed daily intake (ADI) levels for various chili - based fl avorings. The genetic modifi cations paved the way for the development of cultivars with controlled pungency levels for the benefi t of different consumer groups. Certain highly pungent cultivars such as Bhut Jolokia and Naga Jolokia need to be commercially exploited for the development of value - added products and fl avorings. The marketing of chilis is restricted to a greater extent to powdered preparations, which needs further inroads in the form of oleoresins besides paprika extracts, which hold a signifi cant demand in the international market.

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CHILI FLAVOR 799

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CHILI FLAVOR 801

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Documents

Handbook of Fruit and Vegetable Flavors (Hui/Vegetable Flavors) || Chili Flavor