8
Plant Foods for Human Nutrition 52: 263–270, 1998. © 1998 Kluwer Academic Publishers. Printed in the Netherlands. Composition of pulp, skin and seeds of prickly pears fruit (Opuntia ficus indica sp.) RADIA LAMGHARI EL KOSSORI 1 , CHRISTIAN VILLAUME 1,* , ESSADIQ EL BOUSTANI 2 , YVES SAUVAIRE 3 and LUC MÉJEAN 1 1 Institut National de la Santé et de la Recherche Médicale (INSERM U308) Equipe de Recherches Aliment et Comportement, 38 rue Lionnois, 54 000 Nancy, France; 2 Laboratoire de Biochimie Nutritionnelle et Métabolique, Faculté des Sciences Cadi Ayyad, Marrakech, Maroc; 3 Laboratoire de Recherche sur les Substances Naturelles Végétales, UPR ES 1677, Montpellier, France ( * author for correspondence) Received 27 January 1998; accepted in revised form 22 August 1998 Abstract. The proximate composition of pulp, skin and seeds of prickly pear cactus (Opun- tia ficus indica) was investigated and is reported on a dry weight basis. The most abundant component of the pulp and skin was ethanol-soluble carbohydrates. Pulp contained glucose (35%) and fructose (29%) while the skin contained essentially glucose (21%). Protein content was 5.1% (pulp), 8.3% (skin) and 11.8% (seeds). Starch was found in each of the three parts of the fruit. Pulp fibers were rich in pectin (14.4%), skin and seeds were rich in cellulose (29.1 and 45.1%, respectively). Skin was remarkable for its content of calcium (2.09%) and potassium (3.4%). Prickly pear is a neglected nutritional source which should be more widely used because of its potential nutrient contribution. Key words: Carbohydrate, Fiber, Minerals, Prickly pear, Protein Introduction Cacti thrive in low annual rainfall countries where the production of more succulent food plants is severely limited. This adaptation to arid and semiarid climates allows them to be an interesting agricultural resource. Under optimal conditions, annual production of the aerial parts of the plant can reach 50 tons of dry matter per hectare. Fresh fruit production from cacti is nearly 40 t/ha/year [1, 2]. About 1500 species of cactus are in the genus Opuntia and are distrib- uted in Europe, Mediterranean countries, Africa, southwestern United States, northern Mexico and other areas [3]. Many species of Opuntia produce edible and highly flavored fruits [4]. Both the fruits and leaves are important nutri- tional and dietary food sources. For a long time, Mexican populations have used the leaves of prickly pear cacti (nopal) for their medicinal benefits [5].

Composition of pulp, skin and seeds of prickly pears fruit (Opuntia ficus indica sp.)

Embed Size (px)

Citation preview

Page 1: Composition of pulp, skin and seeds of prickly pears fruit (Opuntia ficus indica sp.)

Plant Foods for Human Nutrition52: 263–270, 1998.© 1998Kluwer Academic Publishers. Printed in the Netherlands.

Composition of pulp, skin and seeds of prickly pearsfruit ( Opuntia ficus indicasp.)

RADIA LAMGHARI EL KOSSORI1, CHRISTIAN VILLAUME 1,∗,ESSADIQ EL BOUSTANI2, YVES SAUVAIRE3 and LUC MÉJEAN1

1Institut National de la Santé et de la Recherche Médicale (INSERM U308) Equipe deRecherches Aliment et Comportement, 38 rue Lionnois, 54 000 Nancy, France;2Laboratoire de Biochimie Nutritionnelle et Métabolique, Faculté des Sciences Cadi Ayyad,Marrakech, Maroc;3Laboratoire de Recherche sur les Substances Naturelles Végétales,UPR ES 1677, Montpellier, France(∗author for correspondence)

Received 27 January 1998; accepted in revised form 22 August 1998

Abstract. The proximate composition of pulp, skin and seeds of prickly pear cactus (Opun-tia ficus indica) was investigated and is reported on a dry weight basis. The most abundantcomponent of the pulp and skin was ethanol-soluble carbohydrates. Pulp contained glucose(35%) and fructose (29%) while the skin contained essentially glucose (21%). Protein contentwas 5.1% (pulp), 8.3% (skin) and 11.8% (seeds). Starch was found in each of the three partsof the fruit. Pulp fibers were rich in pectin (14.4%), skin and seeds were rich in cellulose(29.1 and 45.1%, respectively). Skin was remarkable for its content of calcium (2.09%) andpotassium (3.4%). Prickly pear is a neglected nutritional source which should be more widelyused because of its potential nutrient contribution.

Key words: Carbohydrate, Fiber, Minerals, Prickly pear, Protein

Introduction

Cacti thrive in low annual rainfall countries where the production of moresucculent food plants is severely limited. This adaptation to arid and semiaridclimates allows them to be an interesting agricultural resource. Under optimalconditions, annual production of the aerial parts of the plant can reach 50tons of dry matter per hectare. Fresh fruit production from cacti is nearly40 t/ha/year [1, 2].

About 1500 species of cactus are in the genusOpuntia and are distrib-uted in Europe, Mediterranean countries, Africa, southwestern United States,northern Mexico and other areas [3]. Many species ofOpuntiaproduce edibleand highly flavored fruits [4]. Both the fruits and leaves are important nutri-tional and dietary food sources. For a long time, Mexican populations haveused the leaves of prickly pear cacti (nopal) for their medicinal benefits [5].

qual3366.tex; 1/12/1998; 10:21; p.1Article: qual 3366 Pips nr. 189334 GSB: 706058 (qualkap:bio1fam) v.1.1

Page 2: Composition of pulp, skin and seeds of prickly pears fruit (Opuntia ficus indica sp.)

264

Figure 1. Prickly pear fruit components.

Both nopal and prickly pear fruit are consumed as fresh vegetables, added tocasseroles, cooked, canned, or used in salads [6]. In addition to these contri-butions, they provide water which is very scarce because of concurrent highenvironmental temperature [7]. Possessing crassulacean acid metabolism, thisgenus of cacti is reported to be four to five times more efficient than mostgrasses in converting the sun’s energy, water and minerals to dry organicmatter [3]. Most research has demonstrated wide genetic diversity of thisgenus. Fernandez et al. [8] suggested the need for plant breeding and ge-netic approaches to improve tissue composition of this plant for human healthissues.

The human medical potential ofOpuntiadepends on its tissue composition[3]. Most of the medicinal research involves the leaves rather than the pricklypear fruit. Such research indicates that chemical composition of nopals de-pends on the variety, the maturation state and the environmental conditions[9]. Several extracts selected fromOpuntia streptacanthastems have hypo-glycemic effects when administered to normal and pancreatectomized ani-mals [10–12]. All the studies of the hypoglycemic properties ofOpuntiaextracts have focused onO. indica, O. lindheimeriand O. robustaspecies[4].

In Morocco, efforts are currently under way to develop the prickly pearproduction and to increase its introduction into various common foods. This

qual3366.tex; 1/12/1998; 10:21; p.2

Page 3: Composition of pulp, skin and seeds of prickly pears fruit (Opuntia ficus indica sp.)

265

has stimulated the need to evaluate the chemical composition of the pulp, skinand seeds of edible prickly pear.

Material and methods

Sample preparation. Two kilograms of edible prickly pear fruits (Qpun-tia ficus indica sp.) were purchased from local markets. They were brushedtwo minutes under distilled water with a nailbrush. The prickly pear skinwas removed from the fruit by peeling (Fig. 1), cut up into small piecesand lyophilized (Christ, Osterode, Germany). Pulp containing seeds werealso cut up into small pieces and lyophilized. Seeds were removed fromthe lyophilized pulp, washed with distilled water and lyophilized. The threelyophilized fractions (pulp, skin and seeds) were ground separately (Retsch,Haan, Germany) and passed through a 100-mesh sieve before analysis. Thesamples were stored at−20 ◦C.

Experimental procedures.Moisture (14.004 and 14.083 methods), lipids(7.055 and 7.056 methods) and ash (14.006 and 14.103 methods) were de-termined according to AOAC methods [13]. Ethanol-soluble carbohydrateswere extracted for 4 hours with 80% ethanol at 80◦C and assayed using acolorimetric method [14]. Fiber composition was determined according to theSouthgate procedure [15]. Nitrogen was determined by a Kjeldahl procedureaccording to AOAC methods (47.021 and 47.023) [16]. The factor 6.25 wasused to convert nitrogen to crude protein. Non-protein nitrogen was extractedfrom a 500 mg sample by dissolution for two hours in 0.004 N NaOH andprecipitation in 1.6 N trichloroacetic acid, then recuperation of the super-natant by centrifugation at 3000 g/min. [17]. Twenty ml of supernatant weremixed with 2.5 ml of concentrated sulfuric acid, then submitted to nitrogendetermination using the Kjeldahl procedure.

Carbohydrate composition was determined by HPLC using a Merck Sys-tem equipped with a refractive index detector (L-7490, Merck, Darmstadt,Germany). A sugar pack column (300× 6.5 mm, Waters Corp Europe, SaintQuentin en Yvelines, France) was used. The flow rate of the 100% watereluant was 0.6 ml/min. The concentrations of products were determined fromthe peak area. Mineral composition was determined by the laboratory ofHygiene and Public Health Research (Nancy, France). After processing un-der high pressure in a microwave oven (Milestone MLS 1200 MEGA), cal-cium, sodium and potassium were evaluated by flame emission (ELEX 6361)[18], magnesium, cooper, zinc, manganese and molybdenum by mass spec-trometry ICP-MS (Fission PQ2+) [19], iron by atomic absorption without

qual3366.tex; 1/12/1998; 10:21; p.3

Page 4: Composition of pulp, skin and seeds of prickly pears fruit (Opuntia ficus indica sp.)

266

Table 1. Crude composition of prickly pear fruit samples (% w/w, dry matter)

Pulp Skin Seed

Protein 5.13± 0.29 c 8.30± 0.90 b 11.8± 1.17 a

Non protein nitrogen 0.025± 0.002 a 0.024± 0.001 a 0.012± 0.003 b

Lipids 0.97± 0.06 c 2.43± 0.32 b 6.77± 0.51 a

Total fibers 20.5± 0.94 c 40.8± 1.32 b 54.2± 1.06 a

Ash 8.50± 0.82 b 12.1± 1.46 a 5.90± 1.25 c

Ethanol-soluble carbohydrates 58.3± 0.45 a 27.6± 0.21 b 1.59± 0.21 c

Starch 4.55± 0.24 b 7.12± 0.60 a 5.35± 1.14 b

Mean± standard deviation; n = 3.In a row, two values with a different letter are significantly different at 95%.

Table 2. Fiber composition of prickly pear fruit (% of total fiber)

Pulp Skin Seed

Hemicellulose 15.5± 0.45 b 20.8± 0.55 a 9.95± 0.58 c

Cellulose 14.2± 1.07 c 71.4± 1.99 b 83.2± 0.25 a

Pectin 70.3± 1.30 a 7.71± 1.45 b 6.69± 0.46 c

Lignin 0.01± 0.01 c 0.06± 0.01 b 0.19± 0.04 a

Mean± standard deviation; n = 3.In a row, two values with a different letter are significantly different at 95%.

flame (Varia Spectra A 400 Zeeman) [20] and phosphorus using nitric: per-chloric digestion followed by an ammonium molybdate colorimetric method(Spectrophotometer Unicam) analysis [21].

Statistical analysis. Results are expressed as mean±SD of samples. Datawere compared using one way analysis of variance (ANOVA) with a 95%confidence interval [22].

Results and discussion

Previous studies on the composition ofOpuntia ficus indicawere largelycarried out on the leaves rather than the prickly pear fruit because of a largerutilization of the leaves than the fruit in Mexico and other Hispanic areas.Chemical composition of raw nopals and prickly pear fruits was described byMunoz-de-Chavez [6]. Protein contents were, respectively, 1.7% and 0.6%.Ether extracts were, respectively, 0.3% and 0.1%. In this experiment, skin,pulp and seeds contained significantly different amounts of starch, although

qual3366.tex; 1/12/1998; 10:21; p.4

Page 5: Composition of pulp, skin and seeds of prickly pears fruit (Opuntia ficus indica sp.)

267

Table 3. Carbohydrate composition of prickly pear fruit (% dry matter)

Pulp Skin Seed

Saccharose 0.22 2.36 0

Glucose 35.0 21.0 0

Fructose 29.6 2.89 0

Raffinose 0 0 0

Galactose 0 0 0

Mannose 0 0 0

Stachyose 0 0 0

Xylose 0 0 0

n=1.

Table 4. Mineral composition of prickly pear fruit (mg/100 g, dry matter)

Pulp Skin Seed

Ca 163 2090 258

Mg 76.1 322 208

Na 7.77 < 0.85 < 0.83

K 559 3430 275

P 0.063 0.064 110

Fe 16.5 8.31 12.1

Cu < 0.78 < 0.85 < 0.83

Zn 1.55 1.70 4.16

Mn 6.99 72.9 < 0.83

Mb < 0.31 < 0.34 < 0.33

n=1.

starch was present only in trace amounts in the mixture of pulp and seedsin the composition table of Favier et al. [23]. Pulp contained significantlyless protein, more ethanol-soluble carbohydrates and less crude fiber thanskin and seeds (Table 1). The protein contents of prickly pear lyophilizedfractions were low (5.3% to 11.3%) compared to the leguminous plants butwere comparable to those of the cereals or other food sources of developingcountries such as sweet potatoes, cassava and yam.

The fiber contents of prickly pear fruit fractions ranged from 20.5% to54.2% and were significantly different from each other. Skin fibers containedthe greatest amount of hemicellulose, pulp fibers were richest in pectin andseed fibers had the highest cellulose content. Both skin and seeds containedless pectin than the pulp. Lignin was the least plentiful fiber component (Ta-

qual3366.tex; 1/12/1998; 10:21; p.5

Page 6: Composition of pulp, skin and seeds of prickly pears fruit (Opuntia ficus indica sp.)

268

ble 2). The quantities of fiber detected in prickly pear fruit could make ita good source of fiber. The beneficial effects of fibers in human health arewidely known; there is no doubt that dietary fibers are important compo-nents of the diet which may help prevent a variety of diseases [24]. Thisbeneficial effect deserves further study, because the addition of 2.5% pectinextracted from prickly pear to a diet containing 15% lard and 0.25% choles-terol has been shown to have a hypocholesterolemic effect in guinea pigs [25].The high fiber content of prickly pear fruit could affect protein utilizationor decrease protein digestibility because fiber may complex proteins. Suchcomplex formation may affect the rate of protein hydrolysis through confor-mational changes [26]. The most abundant component of prickly pear fruitpulp and skin was the ethanol-soluble carbohydrates (Table 3). They consti-tuted more than 50% of the pulp and nearly 30% of the skin. Pulp containeda higher amount of glucose and fructose than skin and seeds. Skin containedessentially glucose but also small amounts of saccharose and fructose. Sac-charose, glucose and fructose were absent in the seeds. Other carbohydratessuch as raffinose, stachyose, verbascose and galactose, known for causing in-testinal discomfort, were absent in the three parts of the prickly pear fruit. Thepresence of a balanced amount of glucose and fructose in the pulp and skinmakes these natural carbohydrate sources of sweetness for food preparations.They also constitute a good source of energy.

Skin contained a high amount of calcium, potassium, magnesium andmanganese (Table 4). Pulp had more iron than skin. Seeds were rich in phos-phorus and zinc. The amounts of minerals in the three lyophilized fractions,especially calcium content, could be related to soil content of these elements.No information concerning the agricultural environment of the samples usedin this study was available but sampling in different Moroccan areas should beconducted to evaluate the effect of different soil compositions on macro- andmicronutrients of prickly pear. The mineral quantities detected in the variousprickly pear fruit fractions could make them a good mineral supplement forjuices or other commercial foods.

In conclusion, prickly pear fruit is an interesting food. Its pulp is richin glucose, fructose and pectin. The skin contains cellulose, calcium andpotassium. The seeds contain cellulose and noticeable amounts of proteinand lipids. Its nutritional use should be encouraged in arid and semi aridareas where each nutritional resource is vital, as well as in other countrieswere foods for improving health are more and more appreciated.

qual3366.tex; 1/12/1998; 10:21; p.6

Page 7: Composition of pulp, skin and seeds of prickly pears fruit (Opuntia ficus indica sp.)

269

Acknowledgments

The authors are most grateful to the staff at the laboratory of Hygiene andPublic Health Research (Nancy, France), Laboratory of Physico-Chemestry(Nancy, France), who carried out many assays with kindness.

References

1. Garcia de Cortazar V, Nobel PS (1991) Prediction and measurement of high annualproductivity ofOpuntia ficus indica. Agr for Meteorol 56: 261–272.

2. Nobel PS, Garcia-Moya E, Quero E (1992) High annual productivities of certain agavesand cacti under cultivation. Plant Cell Envir 15: 329–335.

3. Hegwood DA (1990) Human health discoveries withOpuntiasp. (Prickly Pear). HortScience 25: 1515–1516.

4. Enigbokan M, Felder TB, Thompson JO, Kuti JO, Ekpenyong KI (1996) Hypoglycemiceffects ofOpuntia ficus indicaMill. Opuntia lindheimeriEngelem andOpuntia robustaWendel in streptozotocin-induced diabetic rats. Phytotherapy Res 10: 379–382.

5. Ibanez-Camacho R, Meckes-Lozoya M, Mellado-Campos V (1983) The hypoglycemiceffect of Opuntia streptacanthastudied in different animal experimental models. JEthnopharmacology 7: 175–181.

6. Munoz-de-Chavez M, Chavez A, Valles V, Roldan JA (1995) Plants in human nutrition.World Rev Nutr Diet 77: 109–134.

7. Villareal A (1959) El nopal como forrage. Rev Chapingo, Jan–Feb: 220–225.8. Fernandez ML, Trejo A, McNamara DJ (1994) Prickly pear (Opuntiasp.) pectin alters

hepatic cholesterol metabolism without affecting cholesterol absorption in guinea pigsfed a hypercholesterolemic diet. J Nutr 124: 817–825.

9. Rodriguez-Felix A, Cantwell M (1988) Developmental changes in composition andquality of prickly pears cactus cladodes (nopalitos). Plant Foods Hum Nutr 38: 83–93.

10. Ibanez-Camacho R (1978) Nopal-Opuntia sp.Medicina traditional (México). 4: 1.11. Ibanez-Camacho R, Roman-Ramos R (1979) Efecto hypoglucemiante del nopal. Arch

Invest Med 10: 223.12. Frati-Munari AC, Quiroz-Lazaro JL, Altaminaro-Bustamante P, Ariza-Andraca CR

(1988) Effectos de differentes dosis de nopalOpuntia streptacanthaLemaire en lapreuba de tolerancia a la glucosa en individuos sanos. Arch Invest Med Mexico 19:143–148.

13. AOAC. (1980) Official Methods of Analysis, 13th edn. Washington, DC: Association ofOfficial Analytical Chemists. Methods number: 14.004–14.006 p. 211, 14.083 p. 223,14.103 p. 225, 7.055–7.056 p. 132.

14. Roe JH (1955) The determination of sugar in blood and spinal fluid with anthronereagent. J Biol Chem 212: 335–343.

15. Southgate DAT (1969) Determination of carbohydrates in food. II. Unavailable carbo-hydrates. J Sci Food Agric 20: 331–335.

16. AOAC (1984) Official Methods of Analysis, 14th edn. Washington, DC: Association ofOfficial Analytical Chemists. Methods number: 47.021–47.023 p. 988.

17. Becker HC, Milner RT, Nagel RH (1970) A method for the determination of non proteinnitrogen in soybean meal. Cereal Chem 17: 447.

qual3366.tex; 1/12/1998; 10:21; p.7

Page 8: Composition of pulp, skin and seeds of prickly pears fruit (Opuntia ficus indica sp.)

270

18. AFNOR (1984) Dosage du sodium et du potassium. Méthode par spectrométried’émission de flamme. NF-T-90-019.

19. AFNOR (1996) Protocole d’évaluation d’une méthode alternative d’analyse physico-chimique quantitative par rapport à une méthode de référence XP-T-90-210.

20. AFNOR (1996) Dosage d’éléments minéraux – Méthode par spectrométrie d’absorptionatomique avec atomisation électrothermique FD-T-90-119.

21. AFNOR (1997) Dosage du phosphore. Dosage spectrophotométrique à l’aide du molyb-date d’ammonium NF-EN-1189.

22. Snedecor GW, Cochran WG (1984) Classification à une voie, analyse de variance. In:Méthodes statistiques, Snedecor GW and Cochran WG eds., Association de coordinationtechnique agricole, Paris, pp. 287–333.

23. Favier JC, Ireland-Ripert J, Toque C, Feinberg M (1995) Répertoire général des aliments.Table des compositions. INRA eds. Lavoisier Tec et Doc, Paris, p. 599.

24. Roehrig K (1988) The physiological effects of dietary fiber (a review). Food Hydrocol-loïds 2: 1–17.

25. Fernandez ML, Lin ECK, Trejo A, McNamara DJ (1992) Prickly pear (Opuntia sp.)pectin reverses low density lipoprotein receptor suppression induced by a hypercholes-terolemic diet in guinea pigs. J Nutr 22: 2330–2340.

26. Kakade M, Rackis JJ, Mcghee JE, Puski G (1974) Determination of trypsin inhibitoractivity of soy products: A collaborative analysis of an improved procedure. CerealChem 51: 376–382.

qual3366.tex; 1/12/1998; 10:21; p.8