Food Chemistry 131 (2012) Contents lists available at SciVerse ScienceDirect. Food Chemistry

Transcription

1 Food Chemistry 131 (2012) Contents lists ville t SiVerse SieneDiret Food Chemistry journl homepge: Nutrients nd ntinutrients in owpe nd horse grm flours in omprison to hikpe flour: Evlution of their flour funtionlity Ydhlly N. Sreerm, Vdkkoot B. Sshikl, Vishws M. Prtpe, Vsudev Singh Deprtment of Grin Siene nd Tehnology, Centrl Food Tehnologil Reserh Institute, Counil of Sientifi nd Industril Reserh (CSIR), Mysore , Indi rtile info strt Artile history: Reeived 24 Mrh 2011 Reeived in revised form 15 July 2011 Aepted 6 Septemer 2011 Aville online 12 Septemer 2011 Keywords: Underutilized legumes Nutrients Antinutritionl ftors Flour funtionlity Composite flour Legume flour The nutrient omposition, ntinutritionl ftors nd flour funtionlity of owpe nd horse grm flours were evluted in omprison to hikpe flour hrteristis. Protein ontent of these flours ws in the rnge of %. Ft ontent ws highest in hikpe (4.8%) nd lowest in horse grm (1.4%). Resistnt strh nd phyti id were signifintly higher in owpe flour. Compred to hikpe nd owpe, horse grm hs more rohydrte, dietry fire, polyphenols nd trypsin inhiitor tivity nd less oligoshrides. Horse grm nd hikpe flours hd the highest wter nd oil sorption pities with vlues of 148.1% nd 109.3%, respetively. Although emulsion tivity (58.1%) nd stility (52.0%) were superior in horse grm, foming pity nd fom stility were signifintly higher in hikpe nd owpe flours, respetively. These results suggest the potentil utility of owpe nd horse grm flours s sustitutes for hikpe flour in some food produts formultions. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introdution As good soures of proteins, rohydrtes, severl wtersolule vitmins, nd minerls, legumes in generl mke mjor ontriution to humn nutrition. Chikpe (Cier rietinum L.) is one of the oldest nd most widely onsumed legumes in the world, prtiulrly in tropil nd sutropil res. Chikpe nd its flour (grnzo flour or esn) re eing used extensively in food proessing in mny ountries euse of its idel ell wll polyshride omposition, verstile flour funtionlity nd reltively high ontent of oil. It is stple ingredient in south nd southest Asin uisines. Its flour is the min ingredient in mny Indin sweets, desserts nd svoury produts. It is lso used in Itlin nd Frenh uisines to mke vriety of desserts, noodles, snks nd min dishes (Aljji & El-Adwy, 2006). However, other underutilised legumes, suh s owpe (Vign unguiult L. Wlp.) nd horse grm (Mrotylom uniflorum L.) hve een reognised s potentil soures of protein nd other nutrients (Prinywiwtkul, MWtters, Beuht, & Phillips, 1996; Ntionl Ademy of Sienes, 1979). Cowpe is ultivted for its immture pods nd mture seeds nd is onsumed extensively in Afri nd, to lesser extent, in Asi (Prinywiwtkul et l., 1996). Similrly, horse grm is lrgely ultivted, espeilly in dry res of Austrli, Burm, Indi nd Sri Lnk, minly for niml feed. It is lso used s vegetle in Indi nd is known s the poor mn s pulse rop in southern Indi (Kdm & Slunkhe, 1985). Both Corresponding uthor. Tel.: ; fx: E-mil ddress: yns@ftri.res.in (Y.N. Sreerm). owpe nd horse grm re low in ft nd re exellent soures of protein, dietry fire, vriety of mironutrients nd phytohemils (Kdm & Slunkhe, 1985; Siddhurju & Beker, 2007). The use of owpe nd horse grm flours, s ingredients in omposite flours nd funtionl foods, is limited, due to the presene of ertin phytohemils with ntinutrient effets tht limit the nutritive vlue of these legumes. Conventionl proessing methods, suh s soking, oiling, germintion, nd fermenttion, re widely used to derese the ontent of these undesirle omponents, whih results in enhned eptility nd nutritionl qulity in ddition to optiml utilistion of these legumes s humn food (Kdm & Slunkhe, 1985). However, reently, helth-promoting nd disese-preventing properties hve een ttriuted to these phytohemils with ntinutrient effets, thus ttrting more nd more interest from oth reserhers nd food mnufturers (Jos & Steffen, 2003). Improved utilistion of these underutilised legume flours n e mximised through n understnding of their physil nd hemil omponents nd through the implementtion of diverse proessing strtegies to filitte the development of eonomilly vile lterntive produts. In this respet, some reent studies hve indited tht the onsumption of owpe nd horse grm ould e improved y proessing them into ingredients tht n e used in food produt pplitions (Prinywiwtkul et l., 1996; Sreerm, Sshikl, & Prtpe, 2008). The present study is imed t produing omposite flours from little-known legumes, suh s owpe nd horse grm, nd exploring the possiility of using them s ingredients for food proessing. However, the use of legume flours in vrious food formultions is /$ - see front mtter Ó 2011 Elsevier Ltd. All rights reserved. doi: /j.foodhem

2 Y.N. Sreerm et l. / Food Chemistry 131 (2012) dependent on their nutritionl nd funtionl properties. Therefore, n investigtion ws rried out first, to eluidte the nutritionl nd funtionl properties of owpe nd horse grm flours in omprison to hikpe flour hrteristis. This is expeted to give insight into the possile utilistion of owpe nd/or horse grm flour s prtil sustitutes of hikpe flour in snk, onfetionry nd other trditionl food produts. 2. Mterils nd methods 2.1. Chemils The Folin Ciolteu regent, glli id, ovine trypsin, enzyl- DL-rgenine-p-nitronilide hydrohloride (BAPNA), rffinose, sthyose nd versose were purhsed from Sigm Chemil Co. (St. Louis, MO). All other regents were of nlytil grde Smple preprtion Cowpe, horse grm nd hikpe seeds ommonly ultivted in Indi were purhsed from lol mrket in Mysore, Indi. Dehulling nd seprtion of hulls from otyledons were done s desried previously (Sreerm, Neelm, Sshikl, & Prtpe, 2010), using grin-testing devie (Strong-Sott Ltd., Winnipeg, MB, Cnd). The seprted, dehulled otyledons were ground using offee en grinder, to otin fine powder tht pssed through 60 mesh sieve. All smples were deftted y lending with hexne (1:5 w/v, 5 min, three times) in Wring lender t mient temperture nd ir-dried for 12 h. Deftted flours were vuum-pked in polythene pouhes nd stored in the drk, t 4 C, until used Nutrient omposition Anlyses of owpe, horse grm nd hikpe flours for rude protein, ft, sh nd moisture ontents were rried out essentilly ording to the stndrd methods of the Assoition of Offiil Anlytil Chemists (1990). The rohydrte ontent ws determined s the weight differene using moisture, rude protein, lipid nd sh ontent dt. Totl dietry fire (TDF) ws determined y rpid enzymti ssy (Asp, Clves, Johnson, Hlmer, & Siljestrom, 1983). Resistnt strh ws isolted nd determined y n enzymti method (Mngl, Mlleshi, Mhdevmm, & Thrnthn, 1999). The nlytil vlues were evluted from the men of three determintions for eh smple Antinutritionl ftors Phenoli ompounds Totl phenolis from deftted legume flours were extrted with 80% queous methnol ontining 1% HCl (1:50 w/v) y refluxing in oiling wter th for 30 min (3 times). The refluxed mteril ws onentrted under vuum in rotry flsh evportor nd the totl phenoli ontent ws mesured ording to the method of Singleton, Orthofer, nd Lmuel-Rventos (1999). The ontent of totl phenolis in eh extrt ws determined, using stndrd urve prepred for glli id, nd expressed s mg of glli id equivlents (GAE) per grmme of deftted mel flour Phytte ontent Phyti id ontents of deftted legume flours were determined y the method of Hug nd Lntzsh (1983). The phyti id ontent ws lulted from lirtion urve using phytte phosphorus slt in the rnge of lg Trypsin inhiitory tivity (TIA) Trypsin inhiitor ws extrted from 1 g of flour, using 10 ml of 0.1 M Tris HCl uffer (ph 8.2) t 4 C with stirring overnight. TIA of flours ws determined ording to the method of Kkde, Rkis, MGhee, nd Puski (1974) with modifitions, s desried y Sreerm, Sshikl, & Prtpe (2008). The inhiitor onentrtion ws optimised to otin 40 70% inhiition of trypsin. One trypsin tivity unit ws defined s n inrese of 0.1 sorne unit t 410 nm. Trypsin inhiitory tivity hs een defined in terms of trypsin units inhiited per grmme of smple. Approprite ontrols, ontining uffer insted of smple, were mintined. Inhiition of trypsin tivity ws lso determined in the presene of vrious onentrtions of uffer extrts of legume flours (15 75 lg/ml) to derive the IC 50 vlues. IC 50 ws defined s the onentrtion of extrt required to inhiit 50% of the enzyme tivity nd otined grphilly using n inhiition urve Fltulene ftors Fltulene-forming oligoshrides were first extrted from deftted owpe, horse grm nd hikpe flours y treting 5 g of eh smple with 25 ml of 80% ethnol t room temperture (27 ± 2 C) nd stirring on mgneti stirrer for 30 min. The extrtion ws repeted thrie. The extrts were pooled nd onentrted using rotry evportor under vuum. The residue ws mde up to 5 ml with deionised wter nd the sugrs were seprted on Kromsil NH 2 nlytil HPLC olumn (250 4 mm, prtile size 5 lm; Phenomenex Torrne, CA, USA) ording to the method of Sreerm et l. (2010), using Shimdzu HPLC system (LC-10ATVP, Shimdzu Corportion, Jpn). Dt signls were quired nd proessed on PC running the Clss VP softwre. Oligoshrides in the extrt were deteted using refrtive index detetor (RID-10A) nd identified y ompring their retention times with those of known stndrds. Stndrds used were rffinose, sthyose nd versose Funtionl properties Generl The funtionl properties of non-deftted flours were evluted under the sme onditions ording to the following methods Nitrogen soluility The solule nitrogen ontents of legume flours, s funtion of ph, were determined y extrtion of the protein t different ph vlues rnging from 2 to 10 ording to the method desried y Boye et l., The mount of protein in the superntnt ws determined y the method of Brdford (1976). The perentge of solule protein ws lulted s the perentge rtio of protein in the superntnt to tht of the totl protein in the initil smple Wter nd oil sorption pity Flour wter sorption pity (WAC) ws determined ording to the method desried y Anderson, Conwy, Pfeifer, nd Griffin (1969). Flour wter soluility index (WSI) ws determined from the mount of dried solids reovered y evporting the superntnt from the flour wter sorption test (Anderson et l., 1969). Flour oil sorption pity (OAC) ws estimted y entrifuging known quntity of flour sturted with penut oil fter the proedure of Sosulski (1962). The mount of oil retined ws lulted y mesurement of differene in the weights of the smple efore nd fter equilirtion with oil Foming nd emulsifying properties Foming pity (FC) nd foming stility (FS) were determined ording to the method desried y Chu nd Cheung (1998). Emulsion tivity (E) nd emulsion stility (Es) were

3 464 Y.N. Sreerm et l. / Food Chemistry 131 (2012) evluted essentilly ording to the method of Ytsumtsu, Swd, nd Moritk (1972) Sttistil nlysis All mesurements were rried out in triplite. Dt otined were nlysed using one-wy nlysis of vrine (ANOVA) with signifine t p < Signifint differenes mong men vlues were determined y Dunn s multiple rnge test (Dunn, 1955). 3. Results nd disussion 3.1. Nutrient omposition Nutrient omposition of hikpe, owpe nd horse grm flours is shown in Tle 1. The moisture ontent of hikpe flour ws signifintly higher thn those of owpe nd horse grm flours. Protein ontent of the three flours ws in the rnge of %, with no sttistilly signifint differene etween the flours. The protein ontent is omprle to those of other edile leguminous seed flours, suh s pigeon pes, some vrieties of owpe nd soy ens (Olofe, Adeyemi, & Adedirn, 1994). Totl rohydrte, determined y differene, ounted for more thn 60% of the grin omposition. There ws no signifint differene etween the rohydrte ontent of hikpe nd owpe flours. However, horse grm flour hs more rohydrtes. The ft ontent of the three flours rnged from 1.4% to 4.8% with sttistilly signifint differenes etween the flours. Horse grm flour hd the lowest vlue of ft while hikpe hd the highest vlue. More ft in hikpe flour might e disdvntgeous in terms of the shelf life nd keeping qulities of this flour. However, this is n importnt property of hikpe flour, enling its wide utilistion in food produts. Higher ft in hikpe flour lso enhnes the ility of flour to sor nd retin oil, improves inding of the struture, enhnes flvour retention, improves mouth feel nd redues moisture nd ft losses of food produts (Sreerm, Sshikl, & Prtpe, 2008). The lower lipid ontent of horse grm flour my e utilised s ingredients in weight restrition diets. Compred with owpe nd horse grm, hikpe flour reorded the lowest sh ontent. Horse grm flour ontins the highest mount of TDF, followed y hikpe nd owpe flours. Similrly, the insolule dietry fire (IDF), whih omprises lignin, ellulose nd some hemielluloses nd solule dietry fire (SDF) were lso higher in horse grm flour (Tle 1). Among the flours, owpe ontins the lowest mount of IDF. These vlues re similr to the vlues reported for hikpe (Cost, Queiroz-Monii, Reis, & Oliveir, 2006) nd horse grm (Sreerm, Sshikl, & Prtpe, 2008). The high ontent of dietry fire in horse grm flours might e helpful in terms of mintining positive effets on intestine nd olon physiology, Tle 1 Nutrient omposition of legume flours, lulted s % of dry mtter. * Constituent Chikpe Cowpe Horse grm Moisture 8.2 ± ± ± 0.2 Protein 23.7 ± ± ± 1.0 Crohydrte # 61.1 ± ± ± 2.1 Ft 4.8 ± ± ± 0.0 Ash 2.2 ± ± ± 0.0 Totl dietry fire 14.8 ± ± ± 0.5 Solule 1.1 ± ± ± 0.0 Insolule 13.7 ± ± ± 0.4 Resistnt strh 1.9 ± ± ± 0.2 Men vlues ering different letters (,, ) in the sme row re signifintly different (P < 0.05) on pplition of Dunn s multiple rnge test. * Results re mens ± stndrd devition of triplite determintions. # By differene s 100-(moisture + protein + sh + ft). esides other homoeostti nd therpeuti funtions in humn nutrition. The results presented in Tle 1 lso indite tht legume flours ontin signifint quntities of resistnt strh (RS). Sttistilly signifint higher resistnt strh ontent ws oserved in owpe flour. The RS in legume flours present vrious physiologil effets in the gstrointestinl trt of humns. These inlude ltertion of the gstrointestinl trnsit time, stiety hnges, influene on the levels of ody holesterol, fter-mel serum gluose nd insulin levels, fltulene nd ltertion in nutrient iovilility (Hopwell, Yeter, & Ullrih, 1993) Antinutritionl ftors The onentrtions of the ntinutritionl ftors in flours of hikpe, owpe nd horse grm re shown in Tle 2. Cowpe flour showed the highest phyti id ontent, followed y hikpe nd horse grm flours. These vlues re omprle to the vlues reported for hikpe (9.7 mg/g), lk grm (11 mg/g), lentil (12. 5 mg/g), red kidney en (14.4 mg/g) nd white kidney en (12.3 mg/g) (Rehmn & Slriy, 2005). However, the phyti id ontents of ll three legumes were higher thn the levels reported for pigeon pe (2.2 mg/g) nd mr groundnut (2.9 mg/100 g) (Igedioh, Olugemi, & Akppunm, 1994). Besides lowering the iovilility of minerls nd inhiiting the digestiility of proteins, phyti id is lso implited in the hrd-to-ook phenomenon of legumes (Stnley & Aguiler, 1985). However, its presene is lso enefiil euse it my hve positive nutritionl role s n ntioxidnt nd ntiner gent (Turner, Pphzy, Hygrth, & Mkelvie, 2002). Among the different flours, the ontents of totl polyphenols were signifintly higher in horse grm thn in owpe, whih is higher thn hikpe (Tle 2). The phenoli ontent ppered to e similr to those of erlier reports in hikpe nd horse grm milled frtions (Sreerm et l., 2010) nd owpe vrieties (Preet & Puni, 2000). However, the phenoli ontent in these flours is lower thn those reported for eh pe (Shhidi, Chvn, Nzk, & Amrowiz, 2001), owpe, pe, pigeon pe nd hikpe (Reddy, Pierson, Sthe, & Slunkhe, 1985). Phenoli ompounds re known to intert with proteins, forming omplexes whih, in turn, derese the soluility of proteins nd mke protein omplexes less suseptile to proteolyti ttk thn re the sme proteins lone (Reddy et l., 1985). Besides, they impir strh nd dishride ssimiltion nd intert with proteolyti enzymes inhiiting their tivity. However, plnt phenolis re reeiving growing interest due to their potentil role s protetive ftors ginst free rdilmedited pthologies, suh s ner nd theroslerosis in humns (Kehrer, 1993). The ontents of oligoshrides in the three legume flours re shown in Tle 2. The oligoshrides, nmely, rffinose, sthyose nd versose, were deteted in ll the smples. Chikpe Tle 2 Antinutritionl ftors in legume flours. * Antinutrionl ftor Chikpe Cowpe Horse grm Phyti id (mg/g) 12.1 ± ± ± 0.4 Polyphenols (mg GA/g) 10.8 ± ± ± 0.4 Oligoshrides (mg/g) Rffinose 8.6 ± ± ± 0.0 Sthyose 19.1 ± ± ± 0.4 Versose 7.2 ± ± ± 0.0 Trypsin inhiitor tivity Units/g 6452 ± ± ± 18 IC 50 (lg/ml) Men vlues ering different letters,, in the sme row re signifintly different (P < 0.05) on pplition of Dunn s multiple rnge test. * Results re mens ± stndrd devition of triplite determintions.

4 Y.N. Sreerm et l. / Food Chemistry 131 (2012) flour ontined the highest mount of totl -gltosides, followed y owpe nd horse grm flours. Within the oligoshrides, sthyose ws the prinipl oligoshride in ll three legume flours, wheres versose ws present in minor quntities in owpe nd horse grm flours. The ontents of these oligoshride re omprle to the most reently reported vlues in the milled frtions of hikpe nd horse grm (Sreerm et l., 2010). Rffinose, sthyose nd versose -gltosides from pulses re ustive gents of fltulene in humns. These oligoshrides re not digested y humns euse the intestinl muos lks the hydrolyti enzyme, -1, 6-gltosidse. Miroflor in the lower intestinl trt metolise these oligoshrides nd produe lrge mounts of ron dioxide nd hydrogen nd smll quntity of methne, whih uses fltus prodution (Rkis, 1974). Aumultion of fltus in the intestinl trt results in disomfort, dominl rumlings, rmps, pin nd dirrhoe. However, it is well known tht lne of intestinl teril flor is importnt, whih ould dominte pthogeni orgnisms nd thus improve humn helth. These glto-oligoshrides filitte the growth of intestinl ifidoteri. In ft, mny preioti oligoshrides re used s ingredients in vrious produts, suh s soft drinks, ookies, erels, ndies nd infnt foods (Nkkuki, 2003). The hikpe, owpe nd horse grm flours, whih ontin sustntil mounts of oligoshrides, my e used s ingredients in funtionl foods. The men vlues for the trypsin inhiitor tivities of the different legume flours re presented in Tle 2. Trypsin inhiitory tivity of horse grm flour ws signifintly higher thn those of the other two flours. The TIA of owpe flour ws higher thn tht of hikpe flour. At the sme onentrtion, horse grm extrt inhiited trypsin to greter extent thn did hikpe nd owpe extrts (Fig. 1). The onentrtions neessry to inhiit 50% of the initil trypsin tivity (IC 50 ) were 44.8, 38.2 nd 29.4 lg/ml for hikpe, owpe nd horse grm, respetively (Tle 2). These inhiitory tivities re omprle to the reported inhiitory tivities in the milled frtions of hikpe nd horse grm (Sreerm et l., 2010) nd owpe flour (Prinywiwtkul, Eitenmiller, Beuht, MWtters, & Phillips, 1996). Protese inhiitors form stle omplexes with digestive enzymes nd inhiit their tivity. The presene of protese inhiitors in food dereses the pprent nutritionl qulity of proteins in the diet y ffeting the ility of ody digestive enzymes to degrde dietry protein, nd thus limiting the intke of mino ids needed to onstrut new proteins. Inhiition (%) Chikpe Cowpe Horse grm However, in ertin situtions the effets of inhiitors on protein digestion might e dvntgeous, e.g. y improving the intt sorption of some therpeuti proteins, suh s orlly delivered insulin. Moreover, the ontrol of proteses tivity is onsidered to ply deisive role in wide rnge of iologil proesses nd mlfuntioning relted to ner progression. Severl in vitro nd in vivo studies hve provided evidene tht ertin protese inhiitors of legume seeds (Bowmn Birk types of protese inhiitors) re effetive t preventing or suppressing rinogen-indued trnsformtion (Kennedy, 1998). However, the positive or negtive effet of ll enzyme inhiitors depends on their ontent in different legumes nd on the dose nd frequeny of onsumption. Even though the hikpe, owpe nd horse grm flours ontin high levels of protese inhiitors, these ould e intivted y hydrotherml tretment. Suh proessed legume flours ould onstitute vlule dditions to monogstri diets when supplemented with erel protein, nd speifilly whet flour Funtionl properties Protein/nitrogen soluility To provide useful informtion on effetive utilistion of owpe nd horse grm flours in vrious food produts, the protein soluility of the flours ws investigted t ph vlues rnging from 2 to 10. The differenes in protein soluility, s ffeted y ph, re shown in Fig. 2. The protein soluility (of ll three legume flours) ws lowest t ph 4 6 nd highest t ph 2 3 nd The sttistilly signifint lowest soluility vlue oserved t ph 4 ws 6.14% for the hikpe smple wheres, t the sme ph, owpe nd horse grm showed soluility vlues of 14.9% nd 46.8%, respetively. In ontrst, the protein soluilities of owpe (8.19%) nd horse grm (16.4%) were lowest t ph 5.0 (Fig. 2). This might represent the isoeletri point region t whih protein protein intertions disfvour soluility when ompred to the other ph levels studied. On the other hnd, protein soluility rnged etween 69.6% nd 73.6% t ph 7 with no signifint differenes oserved etween flours. There ws mrked inrese in soluility, ttining mximum vlues of 96.2%, 94.5% nd 93.6% t ph 10.0 for hikpe, owpe nd horse grm, respetively, with no signifint differenes oserved etween flours. These results suggest tht, t lkline ph, there is greter extrtion of the solule proteins. However, t ph 2.0, the soluility otined for horse grm flour (84.1%) ws signifintly higher thn the vlues otined for owpe (72.3%) nd hikpe (67.0%) flours (Fig. 2). Similr findings were reported for rw owpe nd hikpe flours y Ghvidel nd Prksh (2006). For food pplitions, protein soluility is n importnt prmeter tht influenes the extent of utilistion in Inhiitor onentrtion (µg/ml) Fig. 1. Trypsin inhiitory tivities of hikpe, owpe nd horse grm flour uffer extrts. Trypsin ws pre inuted with different onentrtions of extrt t 37 C for 10 min nd ssyed for remining tivity. The dt points re the mens ± SD from three experiments. Vlues mrked with different letters (,, ) re signifintly different (p<0.05). Fig. 2. Effet of ph on nitrogen soluility of flours prepred from hikpe, owpe nd horse grm. The dt points re the verge vlues from three independent experiments.

5 466 Y.N. Sreerm et l. / Food Chemistry 131 (2012) different food mtries. In some ses, suh s everges, high protein soluility is determinnt for pplition s fortifition ingredient. Therefore, horse grm flour, whih exhiited signifintly higher soluility t ph 4.0 (46.8%), ould mke it very promising ndidte for use in idi everges. Nevertheless, mong the funtionl properties of proteins, soluility is proly the most ritil, euse it ffets other properties, suh s emulsifition ility, fom-forming pity nd gel formtion. Overll, the protein soluilities of owpe nd horse grm were omprle with hikpe; this ould e of interest s hikpe is very widely used s n ingredient in food produts Wter sorption pity (WAC) nd wter soluility index (WSI) Wter sorption pity of flours plys n importnt role in the food preprtion proess euse it influenes other funtionl nd sensory properties. Furthermore, the rnge of pplition of flours s food ingredients is dependent, to lrge extent, on their intertion with wter. The wter sorption pities of legume flours, under mient onditions, were in the rnge g/ 100 g, where owpe hd the lowest nd horse grm the highest WAC (Tle 3). The results lso showed tht the WAC of the horse grm flour ws higher thn tht of hikpe flour. These vlues re omprle to reported vlues for dehulled legume flours of green grm (122.6 g/100 g), owpe (128.5 g/100 g), nd hikpe (136.2 g/100 g) (Ghvidel & Prksh, 2006). However, the WAC vlue of horse grm flour ws higher thn the reported WAC vlues for lentil (97.4 g/100 g) nd other vrieties of horse grm ( ml/100 g) (Diwkr, Kushwh, & Kushwh, 1996; Ghvidel & Prksh, 2006). It is known tht polr mino id residues of proteins hve n ffinity for wter moleules nd differenes in WAC of different legumes ould e due to the ontent of these mino ids in legumes. In ddition, rohydrte omposition my lso e ftor influening the wter-holding pity of the flours. Flours with high WHC ould e good ingredients in kery pplitions, suh s red formultions, sine higher WAC enles kers to dd more wter to the dough, thus improving the hndling hrteristis nd mintining freshness in red. Furthermore, WAC is ritil property of proteins in visous foods, e.g. soups, dough, ustrds nd ked produts, euse these re supposed to imie wter without dissolution of protein, therey providing ody, thikening nd visosity. Similr to the oservtions mde for the WAC vlues, the highest wter soluility index (WSI) vlue of 8.2% ws oserved in horse grm flour. The WSI vlues of hikpe nd owpe flours were found to e 7.4% nd 6.8%, respetively (Tle 3) Oil sorption pity (OAC) The oil-dsorption pity of ny food ompound is importnt for food pplitions euse it relies minly on its pity to physilly entrp oil y omplex pillry ttrtion proess. In Tle 3 Funtionl properties of flours otined from hikpe, owpe nd horse grm. * Funtionl property Chikpe Cowpe Horse grm Wter sorption pity (g/ ± ± ± g) Wter soluility index (%) 7.4 ± ± ± 0.6 Oil sorption pity (g/100 g) ± ± ± 1.1 Foming pity (%) 46.3 ± ± ± 1.8 Fom stility (%) # 39.2 ± ± ± 1.7 Emulsion tivity (%) 48.8 ± ± ± 0.5 Emulsion stility (%) 45.1 ± ± ± 1.6 Mens with the sme supersript (,, ) within the sme row do not differ signifintly (P > 0.05). * Results re mens ± stndrd devition of triplite determintions. # After 30 min. mny food pplitions, suh s emulsion-type met produts, the ility of food omponent to entrp oil is n importnt hrteristi euse ft ts s flvour retiner, onsisteny trit nd n enhner of mouth feel (Khtt & Arntfield, 2009). The oil sorption pity of owpe nd horse grm flours ws studied nd ompred with tht of hikpe. Signifint differenes in the oil sorption pities were noted mong the legume flours studied. Chikpe flour hd the highest vlue (109.3 g/100 g), whih ws followed y owpe nd horse grm flours (Tle 3). The oil sorption pity of legume flours is negtively orrelted with wter sorption pity, whih is similr to nol mel oil sorption nd wter sorption pities reported y Nzk, Diosdy, nd Ruin (1985). Although owpe nd horse grm flours showed signifintly lower OAC vlues thn did hikpe flour, these vlues re higher thn tht of the reported vlues for red en flour (73.83 g/100 g) (Njintng, Mofung, & Wldron, 2001) nd pigeon pe flour (80.7 g/100 g) (Oshodi & Ekperigin, 1989) Foming properties [foming pity (FC) nd foming stility (FS)] Fom formtion nd stility generlly depend on the interfil film formed y proteins whih keeps ir ules in suspension nd slows down the rte of olesene. Foming properties re dependent on the proteins, s well s on other omponents, suh s rohydrtes present in the flour. The foming properties of the hikpe, owpe nd horse grm flours re presented in Tle 3. The foms produed y these legume flours were reltively thik with low fom volume ut high fom stility fter 30 min. The FC nd FS vlues of flours differed signifintly. The FC of hikpe ws found to e greter thn tht of owpe nd horse grm (Tle 3). Better foming pity of hikpe flour implies greter inorportion of ir ules into the produt. Although, lower vlue of FC (20.8%) for owpe flour ws reported previously (Akuor, Admolekun, O, Ori, & Audu, 2003), the oserved FC ws lower thn the 60.2% reported for owpe protein isolte (Horx, Hettirhhy, Chen, & Jlluddin, 2004). This my e due to differenes in the proteins nd the onentrtions employed. However, the FC of horse grm is similr to the reported vlues in the literture (Sreerm, Sshikl, & Prtpe, 2008). Cowpe flour showed mrkedly higher fom stility fter 30 min thn did hikpe nd horse grm flours (Tle 3). These results indite tht the proteins nd other omponents of owpe flour hve greter ility to form strong nd ohesive film round ir ules nd greter resistne of ir diffusion from the ules. In generl, ll three legume flours depited high fom stility nd my find pplition in ked nd onfetionery produts Emulsifying properties [emulsion tivity (E) nd emulsion stility (Es)] The emulsion tivity reflets the ility nd pity of protein to id in the formtion of n emulsion nd is relted to the protein s ility to sor to the interfil re of oil nd wter in n emulsion. The emulsion stility normlly reflets the ility of the proteins to imprt strength to n emulsion for resistne to stress nd hnges nd is therefore relted to the onsisteny of the interfil re over defined time period (Pere & Kinsell, 1978). The emulsifying tivities nd emulsion stilities of hikpe, owpe nd horse grm flours re shown in Tle 3. The flour of horse grm ws superior to the other flours in emulsifying tivity nd emulsifying stility (signifintly higher thn hikpe nd owpe flours). The inresed E of horse grm flour might e due to the dissoition nd prtil unfolding of gloulr proteins, leding to exposure of hydrophoi mino id residues, whih onsequently inresed the surfe tivity nd dsorption t the oil nd wter interfe. No signifint differenes were oserved etween the emulsifying tivities of hikpe nd owpe flours. However,

6 Y.N. Sreerm et l. / Food Chemistry 131 (2012) emulsion stility vlues of ll the three flours differed signifintly. These results re in onordne with those reported erlier y Mwsru, Muhmmd, Bkr, Yko, nd Mn (2000); who lulted 48.16% nd 54.90% emulsion tivity nd stility, respetively for owpe protein isoltes. However, Rg, Biker, nd Eltiny (2004) reported the emulsion tivity vlue of 50% nd stility vlue of 82% for owpe protein isoltes. Perhps differenes in the hemil ompositions of owpe ultivrs nd protein soluility might hve ounted for the oserved differenes in E nd Es. 4. Conlusions The results of this study indite tht owpe nd horse grm flours re rih in protein, rohydrtes, resistnt strh nd dietry fires. Although hikpe flour hs higher ft ontent, the overll nutrient omposition of these little-known legume flours is omprle to the extensively used hikpe flour, suggesting tht these legume flours ould serve s hep nd lternte soure of proteins. Nitrogen soluility of flours ws good t oth id nd lkline phs. Although oil-sorption nd foming pities were higher in hikpe flour, etter fom stility ws oserved in owpe flour. The horse grm flour hd the highest wter sorption pity, emulsion tivity nd emulsion stility. These fvourle nutritionl nd funtionl properties of owpe nd horse grm flours ould e exploited in the preprtion nd development of food produts, suh s kery produts, soups, extruded produts nd redy-to-et snks. The flours from these underutilised legumes my lso e very ttrtive for produing omposite flours s prtil sustitutes of hikpe flour in snks, onfetionery nd other trditionl food produts. However, only si informtion on nutrition nd flour funtionlity, sed on simple model systems, is provided in this study. Further studies re in progress to understnd the inherent omplexity of protein funtionlity of these flours, in omposite flours nd in food systems. Aknowledgement We thnk Dr. R. Rvi, Sensory Siene Deprtment, Centrl Food Tehnologil Reserh Institute for sttistil evlution of the dt. Referenes Akuor, P. I., Admolekun, F. O., O, C. A., Ori, H., & Audu, I. O. (2003). Chemil omposition nd funtionl properties of owpe nd plntin flour lends for ookie prodution. Plnt Foods for Humn Nutrition, 58, 1 9. Aljji, S. A., & El-Adwy, T. A. (2006). Nutritionl omposition of hikpe (Cier rietinum L.) s ffeted y mirowve ooking nd other trditionl ooking methods. Journl of Food Composition nd Anlysis, 19, Anderson, R. A., Conwy, H. F., Pfeifer, V. F., & Griffin, E. L. (1969). Roll nd extrusion ooking of grin sorghum grits. Cerel Siene Tody, 14, Asp, N. G., Clves, G., Johnson, C. J., Hlmer, H., & Siljestrom, M. (1983). Rpid enzymti ssy of insolule nd solule dietry fire. Journl of Agriulturl Food Chemistry, 31, Assoition of Offiil Anlytil Chemists. (1990).Offiil Methods of Anlysis, 15th ed.; AOAC: Wshington, DC. Boye, J. I., Aksy, S., Roufik, S., Riéreu, S., Mondor, M., Frnworth, E., et l. (2010). Comprison of the funtionl properties of pe, hikpe nd lentil protein onentrtes proessed using ultrfiltrtion nd isoeletri preipittion tehniques. Food Reserh Interntionl, 43, Brdford, M. (1976). A rpid nd sensitive method for the quntittion of mirogrm quntities of protein utilizing the priniple of protein dye inding. Anlytil Biohemistry, 72, Chu, C. F., & Cheung, P. C. K. (1998). Funtionl properties of flours prepred from three Chinese indigenous legume seeds. Food Chemistry, 61, Cost, G. E. A., Queiroz-Monii, K. S., Reis, S. M. P. M., & Oliveir, A. C. (2006). Chemil omposition, dietry fier nd resistnt strh ontents of rw nd ooked pe, ommon en, hikpe nd lentil legumes. Food Chemistry, 94, Diwkr, P., Kushwh, A., & Kushwh, H. S. (1996). Effet of proessing on the funtionl properties of some lol vrieties of horse grm (Dolihos iflorus L.) in Mdy Prdesh. Journl of Food Siene nd Tehnology (Indi), 33, Dunn, D. B. (1955). Multiple rnge nd multiple F-test. Biometris, 11, Ghvidel, R. A., & Prksh, J. (2006). Effet of germintion nd dehulling on funtionl properties of legume flours. Journl of the Siene of Food nd Agriulture, 86, Hug, W., & Lntzsh, H.-J. (1983). Sensitive method for the rpid determintion of phytte in erels nd erel produts. Journl of the Siene of Food nd Agriulture, 34, Hopwell, R., Yeter, R., & Ullrih, I. (1993). Solule fier: Effet on rohydrte nd lipid metolism. Progress in Food nd Nutrition Siene, 17, Horx, R., Hettirhhy, N. S., Chen, P., & Jlluddin, A. M. (2004). Funtionl properties of protein isolte from owpe (Vign unguiult L. Wlp.). Journl of Food Siene, 69, Igedioh, S. O., Olugemi, K. T., & Akppunm, M. A. (1994). Effets of proessing methods on phyti id level nd some onstituents in mr groundnut (Vign suterrne) nd Pigeon pe (Cjnus jn). Food Chemistry, 50, Jos, D. R., Jr., & Steffen, L. M. (2003). Nutrients, foods, nd dietry ptterns s exposures in reserh: A frmework for food synergy. Amerin Journl of Clinil Nutrition, 78, 508S 513S. Kdm, S. S., & Slunkhe, D. K. (1985). Nutritionl omposition, proessing, nd utiliztion of horse grm nd moth en. Critil Reviews in Food Siene nd Nutrition, 22, Kkde, M. L., Rkis, J. J., MGhee, J. E., & Puski, G. (1974). Determintion of trypsin inhiitor tivity of soy produts: A ollortive nlysis of n improved proedure. Cerel Chemistry, 51, Kehrer, J. P. (1993). Free rdils s meditors of tissue injury nd disese. Critil Reviews in Toxiology, 23, Kennedy, A. R. (1998). The Bowmn Birk inhiitor from soyen s n ntirinogeni gent. Amerin Journl of Clinil Nutrition, 68, Khtt, R. Y., & Arntfield, S. D. (2009). Funtionl properties of rw nd proessed nol mel. LWT Food Siene nd Tehnology, 42, Mngl, S. L., Mlleshi, N. G., Mhdevmm & Thrnthn, R. N. (1999). Resistnt strh from differently proessed rie nd rgi (finger millet). Europen Food Reserh nd Tehnology, 209, Mwsru, M. A., Muhmmd, K., Bkr, J., Yko, B., & Mn, C. (2000). Influene of ltered solvent environment on the funtionlity of pigeon pe (Cjnus jn) nd owpe (Vign unguiult) protein isoltes. Food Chemistry, 71, Nzk, M., Diosdy, L. L., & Ruin, L. J. (1985). Funtionl properties of nol mels produed y two-phse solvent extrtion system. Journl of Food Siene, 50, Nkkuki, T. (2003). Development of funtionl oligoshrides in Jpn. Trends in Glyosiene nd Glyotehnology, 15, Ntionl Ademy of Sienes (1979). In Tropil legumes: Resoures for the future, Report of n Ad ho pnel of the dvisory ommittee on tehnology innovtion ord on siene nd tehnology for interntionl development, Wshington, D.C. Njintng, N. Y., Mofung, C. M. F., & Wldron, K. W. (2001). In vitro protein digestiility nd physiohemil properties of dry red en (phseolus vulgris) flour: Effet of proessing nd inorportion of soyen nd ow pe flour. Journl of Agriulturl nd Food Chemistry, 49, Olofe, O., Adeyemi, F. O., & Adedirn, G. O. (1994). Amino id, hemil omposition nd funtionl properties of some oil seeds. Journl of Agriulturl nd Food Chemistry, 42, Oshodi, A. A., & Ekperigin, M. M. (1989). Funtionl properties of pigeon pe (Cjnus jn) flour. Food Chemistry, 34, Pere, K. N., & Kinsell, J. E. (1978). Emulsifying properties of proteins: Evlution of turidimetri tehnique. Journl of Agriulturl nd Food Chemistry, 26, Preet, K., & Puni, D. (2000). Proximte omposition, phyti id, polyphenols nd digestiility (in vitro) of four rown owpe vrieties. Interntionl Journl of Food Sienes nd Nutrition, 51, Prinywiwtkul, W., Eitenmiller, R. R., Beuht, L. R., MWtters, K. H., & Phillips, R. D. (1996). Cowpe flour vitmins nd trypsin Inhiitor ffeted y tretment nd fermenttion with Rhizopus mirospores. Journl of Food Siene, 61, Prinywiwtkul, W., MWtters, K. H., Beuht, L. R., & Phillips, R. D. (1996). Cowpe flour: A potentil ingredient in food produts. Critil Reviews in Food Siene nd Nutrition, 36, Rkis, J. J. (1974). Biologil nd physiologil ftors in soyens. Journl of Ameril Oil Chemists Soiety, 51, 161A 174A. Rg, D. M., Biker, E. E., & Eltiny, A. H. (2004). Frtiontion, soluility nd funtionl properties of owpe (Vign unguiult) proteins s ffeted y ph nd or slt onentrtion. Food Chemistry, 84, Reddy, N. R., Pierson, M. D., Sthe, S. K., & Slunkhe, D. K. (1985). Dry en tnnins: A review of nutritionl implitions. Jurnl of Amerin Oil Chemists Soiety, 62, Rehmn, Z.-U., & Slriy, A. M. (2005). Effets of hydrotherml proessing on ntinutrients, protein nd strh digestiility of food legumes. Interntionl Journl of Food Siene nd Tehnology, 40, Shhidi, F., Chvn, U. D., Nzk, M., & Amrowiz, R. (2001). Nutrient distriution nd phenoli ntioxidnts in ir-lssified frtions of eh pe (Lthyrus mritimus L.). Journl of Agriulturl Food Chemistry, 49, Siddhurju, P., & Beker, K. (2007). The ntioxidnt nd free rdil svenging tivities of proessed owpe (Vign unguiult (L.) Wlp.) seed extrts. Food Chemistry, 101, Singleton, V. L., Orthofer, R., & Lmuel-Rventos, R. M. (1999). Anlysis of totl phenols nd other oxidtion sustrtes nd ntioxidnts y mens of Folin Ciolteu regent. Methods in Enzymology, 299,

7 468 Y.N. Sreerm et l. / Food Chemistry 131 (2012) Sosulski, F. W. (1962). The entrifuge method for determining flour sorption in hrd red spring whet. Cerel Chemistry, 39, Sreerm, Y. N., Neelm, D. A., Sshikl, V. B., & Prtpe, V. M. (2010). Distriution of nutrients nd ntinutrients in milled frtions of hikpe nd horse grm: Seed ot phenolis nd their distint modes of enzyme inhiition. Journl of Agriulturl Food Chemistry, 58, Sreerm, Y. N., Ssikl, V. B., & Prtpe, V. M. (2008). Nutritionl implitions nd flour funtionlity of popped/expnded horse grm. Food Chemistry, 108, Stnley, D. W., & Aguiler, J. M. (1985). A review of texturl defets in ooked reonstituted legumes: The influene of struture nd omposition. Journl of Food Biohemistry, 9, Turner, B. L., Pphzy, J. M., Hygrth, M. P., & Mkelvie, D. I. (2002). Inositol phosphte in the environment. Online Journl of Royl Soiety, Ytsumtsu, K., Swd, K., & Moritk, S. (1972). Whipping nd emulsifying properties of soyen produts. Agriulturl Biologil Chemistry, 36,