Journal of the Science of Food and Agriculture J Sci Food Agric 83:1547–1550 (online: 2003)DOI: 10.1002/jsfa.1570

A simple method to identify chickpea cultivarsto be included in infant food manufactureFrancisco Rincon,∗ Beatrız Martınez and M Victoria IbanezDpto de Bromatologıa y Tecnologıa de los Alimentos, Campus de Rabanales, Edificio C-1, E-14014 Cordoba, Spain

Abstract: A simple method is described for obtaining an overall view of estimated trace elementbioavailability in chickpeas, in order to select chickpea cultivars for use as ingredients in infant foodmanufacture. The two-phase method is based on a set of six raw variables (VRi, i = 1–6): average Fe, Cu,Zn, trypsin inhibitor, phytic acid and tannin contents. In the first phase, each VR was transformed intoa VTi : VT = (VR − min) × 100/(max − min). In the second phase, using information drawn from the set ofthree trace elements VT, a new variable was obtained, defined as the area enclosed within a three-axissystem (TE area). A similar process was used with the data for trypsin inhibitor, phytic acid and tanninto obtain an antinutritive factor area (AF area). Four cultivars (ca2047, ca2219, ca2222 and p678) weredeemed to be of particular interest as possible ingredients of an infant food formula, since they combineda high level of trace elements with a low level of antinutritive substances. In addition, a significantcorrelation was observed between TE and AF areas (r = 0.37, p < 0.05), showing that a high overall traceelement content in chickpeas correlates with high overall antinutritive substance levels. Finally, thechickpea cultivar ca2219 is proposed as the best option, having ruled out other possibilities. 2003 Society of Chemical Industry

Keywords: chickpea; infant foods; food ingredients

INTRODUCTIONThe pea is a green legume often included in meat-based infant weaning food (beikost) formulae, becauseit increases the protein content of ready-to-eat foods.1

However, earlier studies of mineral composition haveshown that the green pea presents a low mineralcontent2 and that the design of meat-based products(as formulated raw ingredients) is a key factor indetermining the content of some mineral elementsin the final product.3 Moreover, iron and zincdeficiencies are among the most commonly observedduring weaning,4 whilst among the factors affectingiron stores in infants, a significant and positiveeffect has been found for commercial baby foods ascomponents of the weaning diet.5 Other legumes,with a higher trace element content, must therefore beconsidered for inclusion in meat-based infant foods.Here the chickpea is of particular interest, since itsprotein content is similar to that of the pea, but it isreported to have a higher trace element content.6–8

Moreover, certain potential protective and therapeuticeffects on lipid and carbohydrate metabolism disordershave been found in rats fed a diet containing heatedchickpeas.9 In addition, no differences have beenreported between desi and kabuli chickpea biotypeswith regard to trace element7 and protein10 contents.

Thus, apparently, any chickpea cultivar may be usedas a weaning food ingredient.

However, one drawback common to all legumesis their low protein digestibility, attributed tothe presence of phytate, trypsin inhibitors andpolyphenols,11 some of which also diminish thebioavailability of trace elements and proteins.12 Forthis reason too the chickpea is of interest, since itsphytic acid content is reportedly lower than thatof other legumes,13 and some chickpea cultivarsadditionally display a low tannin content.10

The aim of this study was to identify chickpeacultivars suitable for use in weaning foods, containinga high level of trace elements and, at the same time,low levels of antinutritive substances.

MATERIALS AND METHODSSeed samplesTable 1 shows the chickpea cultivars included in thestudy, all grown on land belonging to the Centro deInvestigacion y Desarrollo Agrario (CIDA), to the westof the city of Cordoba (37◦52′N, 4◦47′W, elevation137 m). Each cultivar was grown in a separate plotand harvested by hand. Each harvested cultivar wasground in a high-speed mill (Cyclotec-200, Tecator,

∗ Correspondence to: Francisco Rincon, Dpto de Bromatologıa y Tecnologıa de los Alimentos, Campus de Rabanales, Edificio C-1,E-14014 Cordoba, SpainE-mail: bt1rilef@uco.csContract/grant sponsor: CICYT, Ministry of Education and Science(Received 30 September 2002; revised version received 3 June 2003; accepted 28 July 2003)

2003 Society of Chemical Industry. J Sci Food Agric 0022–5142/2003/$30.00 1547

F Rincon, B Martınez, MV Ibanez

Table 1. Chickpea cultivars included in ingredient selection process,

classified according to biotype as desi (d) or kabuli (k)

Cultivar Biotype Cultivar Biotype Cultivar Biotype

ca1276 d ca2075 k ca2206 kca1351 d ca2077 d ca2219 kca1410 d ca2082 k ca2222 kca1449 d ca2087 d ca2223 kca1540 d ca2095 k ca2225 kca1713 d ca2133 k ca2227 kca1776 d ca2137 k iccc1810 kca1778 d ca2138 d jg62 dca1796 d ca2149 k p25 kca2016 k ca2156 k p39 kca2033 k ca2161 k p678 dca2047 d ca2164 k wr315 dca2065 k

Hoganas, Sweden) fitted with a 0.75 mm screen. Foreach cultivar, three aliquots were analysed.

Analytical methodsTrace element content as mg per 100 g was determinedaccording to a method outlined in an earlier paper.7

Antinutritive factors were determined as follows.Trypsin (EC 3.4.21.4) inhibitor activity (TIA) wasdetermined following the method described by Kakadeet al14 and modified by della Gatta et al,15 using BAPA(Sigma B4875) as synthetic substrate, but consideringdifferent values for critical parameters, as reported byMartınez and Rincon.16 One trypsin inhibition unit(TIU) was defined as a decrease of 0.01 absorbanceunits at λ = 410 nm per 10 ml of reaction mixture.17

TIA was expressed as TIU mg−1 defatted chickpeaflour: TIA = (A0 − A1 − A2)/(0.01 × W ), where A0

is the absorbance of the reactive blank, A1 is theabsorbance of the sample blank, A2 is the absorbanceof the sample in which TIA is to be determined,and W is the sample weight. Phytic acid wasextracted following Plaami and Kumpulainen,18 andphytic phosphorus was then determined by AOACmethod 970.3919 and expressed as mg g−1. Condensedtannins were extracted following Terrill et al20 andquantified as catechin units per 100 g using thevanillin reagent method described by Stanley,21 butconsidering different values for critical parameters, asreported by Martınez et al.22 To determine differencesbetween the cultivar selected by the proposed methodand four randomly selected group cultivars fromquadrant III, a comparative study was performed ofFe, Zn and Cu dialysability and of percentage in vitroprotein digestibility. Dialysable Cu, Zn and Fe weredetermined using the technique described by Milleret al23 and later modified by Vaquero et al.24 In vitroprotein digestibility (IVPD) was determined using thetechnique described by Singh and Jambunathan.25

RESULTS AND DISCUSSIONTable 2 shows the mean results obtained for traceelements and antinutritive substances in 37 chickpea

Table 2. Mean trace element and antinutritive factor contents found

in chickpea cultivars

Mean SD Min Max Range

Trace elementsCopper (mg per 100 mg) 1.22 0.15 0.95 1.70 0.74Iron (mg per 100 mg) 4.48 0.52 3.21 5.88 2.67Zinc (mg per 100 mg) 3.53 0.37 2.96 4.38 1.42Antinutritive factorsTrypsin inhibitor

(TIU mg−1)9.16 3.39 3.24 18.31 15.07

Phytic acid (mg g−1) 12.67 2.35 9.02 18.34 9.31Tannin (catechin units per

100 g)0.57 0.21 0.31 1.19 0.89

TIU, trypsin inhibition units.

cultivars. In obtaining overall information on traceelement content, and although Cu, Fe and Zn areexpressed using the same units (mg per 100 g),the existence of different ranges of magnitudeleads to certain difficulties (Table 2). A similarproblem encountered for antinutritive substances iscompounded by the use of units which are differentin nature (Table 2). In these cases it is advisableto transform natural variables,26 because variance isthus made constant across the space of the data forall variables.27 To resolve both problems, we canuse a simple transformation of certain raw variablesinto others, in such a way that a new transformedundimensioned variable (VT) may be expressed as afunction of the raw variable (VR) and its range as

VT = (VR − min)unit × 100(max − min)unit

= (VR − min) × 100(max − min)

In this way, all variables will be expressed in thesame range, from 0 to 100, and this new variableis undimensioned. Fig 1 shows, as an example, thetransformation process for copper.

Now we can obtain an overview of the contentsof these trace elements (Fig 2(a)) and antinutritivesubstances (Fig 2(b)) for each cultivar; the overallview for each cultivar may be defined as the areaincluded within the graphical three-axis system.

Raw variable (VR)

Transformed variable (VT)

0.95 1.70

0 100

VT =(VR - min.) × 100

max. - min.

1.325

50

Figure 1. Copper as raw variable VR (dimensioned as mg per 100 g)converted to transformed variable VT (undimensioned and rangingfrom 0 to 100).

1548 J Sci Food Agric 83:1547–1550 (online: 2003)

Chickpea as ingredient of infant foods

(a)

ca1410 ca1351 ca1449 ca1276 ca1540 ca1713 ca1776 ca1778

ca1796 ca2047 ca2087 ca2138 ca2077 wr315 jg62 p678

ca2016 ca2033 ca2075 ca2082 ca2095 ca2133 ca2137 ca2149

ca2156 ca2164 ca2206 ca2219 ca2222 ca2223 ca2225 ca2227

ca2161 ca2065 p25 p39 icccl810

Cu

FeZn

(b)

ca1410 ca1351 ca1449 ca1276 ca1540 ca1713 ca1776 ca1778

ca1796 ca2047 ca2087 ca2138 ca2077 wr315 jg62 p678

ca2016 ca2033 ca2075 ca2082 ca2095 ca2133 ca2137 ca2149

ca2156 ca2164 ca2206 ca2219 ca2222 ca2223 ca2225 ca2227

ca2161 ca2065 p25 p39 icccl810

TIA

FATN

Figure 2. Overall view of (a) trace element (Cu, Zn, Fe) and(b) antinutritive factor (trypsin inhibitor, TIA; phytic acid, FA;condensed tannins, TN) contents for each chickpea cultivar usingundimensioned variables.

In a second stage, using information drawn fromthe set of three trace elements VT, a new variable wasobtained, defined as the area enclosed within a three-axis system (TE area); a similar process was followedto obtain the antinutritive factor (AF area). Finally, arelationship was established between TE and AF areas,with the result shown in Fig 3. A significant Pearsoncorrelation coefficient was obtained (r = 0.37, p <

0.05, n = 37), so an overall high trace elementcontent correlated with an overall high antinutritivesubstance content. The purpose of the study wasto identify varieties with high trace element contentbut low antinutritive content; such varieties thereforefailed to fit the linear model correlating high traceelement content with high antinutritive content, whichdisplayed statistically significant positive correlation;consequently, the varieties sought were more readilyidentified by graphical means. Quadrant I of Fig 3included chickpea cultivars containing high overallantinutritive factors and low overall trace elementcontent. These cultivars are thus of no interest as infantfood ingredients if the aim is to improve trace elementbioavailability. In contrast, quadrant IV includedcultivars with low overall antinutritive factors andhigh overall trace element content; a selected group

(SG) may be observed (Fig 3). The mean contentsof trace elements and antinutritive substances in thisselected group were as follows: 1.32 mg Cu per 100 g(8.2% above that of the total group, TG), 4.00 mg Znper 100 g (14.3% above TG), 4.62 mg Fe per 100 g(3.1% above TG), 8.53 TIU mg−1 (6.8% below TG),13.88 mg phytic acid g−1 (9.6% above TG) and 0.52catechin units per 100 g (8.8% below TG). The higherphytic acid content of SG compared with TG was duepartly to the exceptionally high phytic acid content oftwo of the four cultivars included within SG (ca2222and p678, with 15.33 and 15.76 mg g−1 respectively;Fig 2(b)), and partly to the fact that both cultivarsdisplay very low tannin and trypsin inhibitor activity,thus giving a low result for AF area and leading to theinclusion of both cultivars in quadrant IV.

Studies performed with a view to improving ironabsorption in infant weaning foods have shown astrong inverse correlation between iron absorption andphytate content,28 and similar effects were reportedearlier for Cu and Zn.29 Therefore cultivars ca2222and p678 were excluded from the selected group,and cultivars ca2047 and ca2219 were proposedas apparently protein-rich ingredients of meat-basedhomogenised beikost, in order to improve traceelement bioavailability from these infant foods.However, a very high tannin content of 0.720 catechinunits per 100 g (26.4% above TG) was found forcultivar ca2047 (desi biotype; Table 1); this is becausepolyphenolic compounds in desi are more than twiceas abundant as those in kabuli25 as a result of greatercoat development in desi cultivars.10 Consequently,ca2219 appears to be the best chickpea cultivar forreplacing the pea as an ingredient of infant beikostin order to obtain an improved trace element balancein the final product and, at the same time, a highdegree of bioavailability due to a lower antinutritivesubstance content. A study was performed to comparedifferences in some parameters, including dialysabilityof Fe, Zn and Cu and IVPD, between the selectedcultivar and four randomly selected cultivars fromquadrant III (see Fig 3). Table 3 shows the differencesbetween the two groups; except for Cu dialysability, allother parameters were significantly better for ca2219

TRACE ELEMENTS AREA

AN

TIN

UT

RIT

IVE

FA

CT

OR

S A

RE

A

2000

4000

6000

8000

10000

2000 4000 6000 8000 10000 12000 14000 16000

I II

III IV

ca2222

p678 ca2047

ca2219

Figure 3. Graphical classification of chickpea cultivars according toboth trace element and antinutritive factor areas.

J Sci Food Agric 83:1547–1550 (online: 2003) 1549

F Rincon, B Martınez, MV Ibanez

Table 3. Differences between selected cultivar and four randomly

selected cultivars from quadrant III (see Fig 3)

Dialysability (%)

Fe Zn Cu IVPD (%)

Selected cultivarca2219 3.80a 27.56a 17.75a 78.43aRandom groupca2065 2.53 14.12 18.05 67.00ca2016 1.10 15.66 20.60 76.24ca2138 2.28 16.48 17.32 69.61p25 1.62 12.72 16.24 72.54Mean 1.88b 14.75b 18.05a 68.80b

IVPD, in vitro protein digestibility.Values with different letters within a column are significantly different(p < 0.05).

from a nutritional point of view. Further research isrequired to establish why Cu dialysability was affecteddifferently from Fe and Zn.

In summary, using a simple two-phase method, thechickpea cultivar ca2219 was identified as the bestoption for replacing pea by chickpea in infant foodformulae. The selection method used may be appliedto other selection processes affecting other parametersand other foods.

ACKNOWLEDGEMENTSThe authors wish to thank to Dra MT Moreno andDr J Gil for the supply of chickpea seeds. This workwas supported by a research grant from the CICYT,Ministry of Education and Science.

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