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1 Food Reserch Interntionl 43 (2010) Contents lists vilble t ScienceDirect Food Reserch Interntionl journl homepge: Digestion profiles nd some physicochemicl properties of ntive nd modified borlotti ben, chickpe nd white kidney ben strches Demet Güzel, Sedt Syr Deprtment of Food Engineering, University of Mersin, Çiftlikköy, 33343, Mersin, Turkey rticle info bstrct Article history: Received 16 Mrch 2010 Accepted 21 July 2010 Keywords: Rpidly digestible strch Slowly digestible strch Resistnt strch Modified legume strch Ntive strches isolted from borlotti ben (Phseolus vulgris L.), chickpe (Cicer riteninum L.), nd white kidney ben (Phseolus vulgris L.) ws modified by pyrodextriniztion (PD), cross-linking with sodium trimetphosphte (CL), het moisture tretment (HMT), nd geltiniztion retrogrdtion (GR) process. The effects of these modifictions on the nutritionlly importnt strch frctions, nmely rpidly digestible strch (RDS), slowly digestible strch (SDS), nd resistnt strch (RS), were studied in both uncooked nd cooked strches. Solubility, swelling power nd geltiniztion prmeters of the ntive nd modified strches were lso studied. PD, CL, nd HMT reduced the swelling power of ll three legume strches. Significnt increses in solubility were observed fter PD nd CL, where GR decresed the solubility of ll strches. CL nd HMT shifted the onset temperture of geltiniztion (T o ) to higher temperture nd tended to decrese the geltiniztion enthlpies (ΔH). PD nd GR strches hs the lrgest proportion of RDS (39 69%) mong uncooked strches where the RDS percentge of uncooked ntive, CL nd HMT strches were only between 2 7%. Compred with ntive strches, ll the modifictions pplied tended to decrese the RDS percentge of cooked strches. The highest decrese in RDS ws determined fter GR tretment for ll the legume strches studied. The totl SDS+RS, the two strch frctions tht hve nutritionl benefits, content of GR nd HMT strches were notbly higher thn the CL nd PD strches Elsevier Ltd. All rights reserved. 1. Introduction Strch is the min crbohydrte in humn nutrition. It is lso common ingredient for food industry becuse of its good thickening nd gelling properties. The nutritionl qulity of strch strongly depends on strch structure nd on its processing. In generl, digestible strches re hydrolyzed by the enzymes in the smll intestine to yield free glucose tht is then bsorbed. Strch digestibility in the humn digestive system cn vry from rpid digestion to indigestibility (Lehmnn & Robin, 2007). These vritions pper to be due to differences in strch components nd their crystllinity (Englyst, Kingmn, & Cummings, 1992). Strch source, processing tretments, nd chemicl modifiction of strch re the min fctors tht influence the extent of strch digestion (Eyru, Shresthb, & Arcot, 2009; Chung, Liu, & Hoover, 2009; Vsnthn & Bhtty, 1998). Englyst et l. (1992), clssified strch into rpidly digestible strch (RDS), slowly digestible strch (SDS), nd resistnt strch (RS) bsed on the rte of glucose relesed during strch Abbrevitions: RDS, rpidly digestible strch; SDS, slowly digestible strch, RS, resistnt strch; PD, pyrodextrinized; GR, geltinized-retrogrdted; CL, cross-linked; HMT, het-moisture treted; T o, onset temperture; T p, pek temperture; T c, conclusion temperture; ΔH, geltiniztion enthlpy; GI, glycemic index. Corresponding uthor. Tel.: ; fx: E-mil ddresses: syrs@yhoo.com, ssyr@mersin.edu.tr (S. Syr). hydrolysis by digestive enzymes. SDS nd RS re the strch frctions tht hve different positive impcts on humn helth. The min potentil helth benefits of SDS re linked to stble glucose metbolism. SDS is reported to hve medium to low Glycemic Index (GI) nd thus reduces the glycemic lod of food product compred to RDS with high GI (Lehmnn & Robin, 2007). It ws lso indicted tht foodstuff contins high levels of SDS is beneficil for individuls with type II dibetes becuse it does not produce hyperglycemi followed by hypoglycemi (Hn & BeMiller, 2007). The other beneficil strch frction, RS, hs been defined s the sum of strch nd its degrdtion products tht re not bsorbed in the smll intestine of helthy individuls (Eurest, 1992). Since it is not digested nd bsorbed in the smll intestine, it reches the colon, where it is fermented by the colonic micro-flor producing shortchin ftty cids (SCFA). Certin SCFA my protect ginst colon crcinogenesis, id in cholesterol nd glucose metbolism nd my led to lower formtion rte of secondry bile cids, which my be involved in lrge-bowel crcinogenesis (Roy et l., 1999; Cummings, 1981). There re mny studies in the literture on the digestibility of modified cerel nd root strches. Gury, Jmes, & Chmpgne (2001) reported process for mking SDS products by enzymtic modifiction of rice strch. They de-brnched the cooked norml nd wxy rice strch with pullulnse, followed by heting nd cooling. High pullulnse concentrtion, less de-brnching time nd /$ see front mtter 2010 Elsevier Ltd. All rights reserved. doi: /j.foodres

2 D. Güzel, S. Syr / Food Reserch Interntionl 43 (2010) subsequent storge t 1 C resulted in mximum SDS formtion, while longer de-brnching time incresed RS content. Shin, Kim, H, Lee, & Moon (2005) investigted the formtion nd structurl chrcteristics of SDS in sweet potto strch under vrious hydrotherml tretments. They reported tht the sweet potto strch with 50% moisture content tht ws heted t 55 C hd the highest SDS content. Vsnthn & Bhtty (1998) studied the effect of retrogrdtion nd nneling on the RS content of mylomize, brley, field pe, nd lentil strches. In their study, they indicted tht the RS content of retrogrded strch gels (6 9%, w/w) were higher thn the ntive strches (3 5%, w/w). Anneling of the retrogrded strch gels by heting nd cooling cycles, reported to further enhnce RS content to 9 19%. In ddition to tht, effect of different tretments nd modifiction techniques, such s pyrodextriniztion (Wng, Kozlowski, & Delgdo, 2001; Lurentín, Cárdens, Rules, Pérez, & Tovr, 2003), het-moisture tretments (Wongsgonsup, Vrvinit, & BeMiller, 2008), crosslinking nd hydroxypropyltion or crosslinking nd cetyltion (Hn & BeMiller, 2007), prtil geltiniztion nd retrogrdtion (Chung, Lim, & Lim, 2006; Escrp, Gonzles, Mns, Grci-Diz, & Sur-Clixto, 1996) on the SDS or RS formtion in corn, rice, potto, lentil, sorghum, cssv, sgu, nd cocoym strches hs lso been studied. However, very little informtion exists regrding the modifiction of the nutritionlly importnt strch frctions of legume strches. Therefore the present work ws undertken to study the impct of pyrodextriniztion (PD), cross-linking (CL), het-moisture tretment (HMT), nd geltiniztion retrogrdtion (GR) tretments on the nutritionlly importnt strch frctions, RDS, SDS, nd RS content, of borlotti ben, chickpe, nd white kidney ben strches. In ddition to tht geltiniztion, swelling, nd solubility properties of the modified strches were lso determined. 2. Mterils nd methods 2.1. Mterils Borlotti ben (Phseolus vulgris L.), chickpe (Cicer riteninum L.) nd white kidney ben (Phseolus vulgris L.), the three commonly consumed legumes in Turkey, were supplied from locl legume processing compny in Mersin, Turkey. Grins were hnd selected to remove foreign mterils nd dmged grins Extrction nd modifiction of legume strch Strch ws extrcted from legume seeds by the method of Schoch & Mywld (1968) with slight modifictions. Legume seeds (150 g) were soked in 500 ml wter contining 0.01% sodium metbisulphite for 18 h t 50 C. Soked seeds were rinsed with distilled wter nd homogenized in blender for 5 min. The homogente ws pssed three times through 150 μm sieve nd the residue ws homogenized two more times. The combined extrcts pssed through 100 μm sieve nd the filtrte ws left to settle for 3 h t room temperture. The resulting superntnt ws discrded nd the sediment ws suspended in 250 ml 5 μm sodium hydroxide solution. After 1 h, the superntnt ws removed nd the residue suspended two more times in the 5 μm sodium hydroxide solution. The residue ws wshed with distilled wter, pssed through 100 μm sieve, neutrlized with 0.1 M hydrochloric cid nd centrifuged t 1500 g (Medifriger, BL-S, JP Select S. A., Abrer, Spin) for 10 min. The residue ws dried t 40 C nd grinded to pss through 100 μm sieve. The yield of strch ws clculted s % yield =(dry weight of strch recovered from extrction 100)/dry weight of legume seeds. Proximte nlysis (moisture, sh, totl protein, nd totl lipid content) of the ntive strch smples were crried out ccording to the stndrd methods of AACC (2000). Four different modifiction methods, which hve the potentil of ltering the strch digestibility, were pplied to ech ntive legume strches obtined Pyrodextriniztion Pyrodextriniztion of legume strch were pplied ccording to the method described by Orozco-Mrtinez & Betncur-Ancon (2004). Briefly, 5 g of strch ws plced in 20 ml glss Petri dishes nd 2.2 M hydrochloric cid ws dded. The strch/hcl rtio ws 80:1 (w/v). The cid ws dispersed on the strch nd the mixture ws llowed to rect for 16 h t room temperture. After tht the mixture were dried in n oven t 110 C for 3 h nd grinded to pss through 100 μm sieve Cross-linking Strch smples (10 g) ws mixed with 20 ml wter contining 1.2 g sodium trimetphosphte nd 1.0 g sodium sulfte ccording to the method given by Sng, Prksh, nd Seib (2007). The ph of the slurry ws djusted to 11.5 by dding 1.0 M sodium hydroxide nd the mixture stirred t 45 C for 3 h. After cooling the ph ws djusted to 6.5 using 1.0 M HCl. The product ws wshed with distilled wter nd centrifuged t 4000xg for 10 min four times nd dried t 40 C. Dried strches were grinded to pss through 100 μm sieve Het-moisture tretment The method of Sir (1964) ws used with slight modifiction for the preprtion of het-moisture treted legume strch. Strch ws weighed into glss jrs nd the moisture level incresed to 22% by dding the pproprite mount of distilled wter. The mixture ws stirred nd the glss jrs seled before equilibrtion t room temperture for 24 h. Then the jrs plced in n ir oven for 16 h t 100 C. After cooling t mbient temperture, the jrs opened nd the smples were dried t 30 C for 48 h in n ir oven. Subsequently strch ws grinded to pss through 100 μm sieve Geltiniztion retrogrdtion tretment Strch smples were suspended in distilled wter (strch/ wter=1:8, w/v) nd utoclved t 121 C for 20 min. After the utoclving process, the smples were cooled to room temperture nd then frozen t 18 C. After 16 h, the smples were freeze-dried (Cryodos-50, Telstr, Terrss, Spin) nd grinded to pss through 100 μm sieve Swelling power nd solubility of the ntive nd modified legume strch Swelling power nd solubility of the strch smples were determined by using the modified method of Subrmnin, Hoseney, nd Brmel-Cox (1994). Strch (0.6 g) ws mixed with 30 ml of distilled wter nd stirred t 85 C on mgnetic stirrer. After 30 min stirring, the mixture ws centrifuged t 2026 g for 15 min. The superntnt ws crefully removed, nd the swollen strch sediment ws weighed (M 1 ). The superntnt ws evported nd dried t 130 C in n oven until constnt weight (M 2 ). Swelling power nd solubility ws clculted from the equtions given below. Swelling power = M 1 M 0 Solubility ð% Þ = M 2 x100 M 0 where M 0 is the initil dry weight of the strch smples Geltiniztion prmeters of ntive nd modified legume strch Geltiniztion properties of the strch smples were determined by differentil scnning clorimeter (Pyris-6 DSC, Perkin-Elmer, Wlthm, MA). For this purpose round 4 mg strch were weighed to n ccurcy of ± g into n luminum DSC pn (B , Perkin-Elmer, Wlthm, MA). Distilled wter (strch/wter=1:3) ð1þ ð2þ

3 2134 D. Güzel, S. Syr / Food Reserch Interntionl 43 (2010) ws dded to the pn by micropipette nd the pn ws then hermeticlly seled. The seled pns were kept for 24 h t +4 C before heting in the clorimeter. Thermogrms were obtined by scnning the smples from mbient temperture to 120 C t 5 C/min heting rtes. Onset temperture (T o ), pek temperture (T p ), conclusion temperture (T c ), nd geltiniztion enthlpy (ΔH) were determined by using the softwre supplied with the instrument Determintion of nutritionlly importnt strch frctions Uncooked smples RDS, SDS, nd RS were determined using the method of Englyst et l. (1992). 0.5 g strch (weighed exctly) nd 10 ml wter were dded to 50-mL screw-cpped polypropylene centrifuge tubes nd mixed by vortexing for 5 min. After mixing, 50 mg gur gum, 10 glss beds, nd 10 ml sodium cette buffer (ph 5.2) were dded to ech tube. The tubes were then incubted with pncretin (8 USP Specifictions, Sigm-Aldrich Co., St. Luis, MO) nd myloglucosidse (from A. niger, 3260 U/ml on soluble strch, Megzyme Ltd, Co. Wicklow, Irelnd ) mixture (5 ml) ccording to Englyst et l. (1992) t 37 C. After 20 (G 20 ) nd 120 min (G 120 ) of incubtion 0.5 ml liquots of hydrolyzte were removed nd dded to 10 ml of 80% ethnol to stop the enzymtic rection. The glucose relesed in ech mesurement ws determined by using glucose oxidse peroxidse dignostic kit (Megzyme Ltd, Co.Wicklow, Irelnd). The remining content of ech tube ws heted in boiling wter bth, treted with 7 M KOH, nd hydrolyzed further with myloglucosidse (50 U/mL) to determine totl glucose (TG). Glucose content ws lso mesured by using the glucose oxidse peroxidse dignostic kit. The RDS, SDS, nd RS percentge of the totl strch were clculted from the vlues of G 20,G 120 nd TG ccording to Englyst et l. (1992) s follows: RDS =G 20 0:9 SDS = ðg 120 G 20 Þ 0:9 TS = TG 0:9 RS = TS ðrds + SDSÞ Cooked smples The ntive nd modified strches (0.5 g) nd 10 ml wter dded to 50-mL screw-cpped polypropylene centrifuge tubes nd mixed by vortexing for 5 min. The tubes were heted in boiling-wter bth for 20 min while gently stirring mgneticlly t low speed. After tht the tubes were plced in 37 C wter bth nd equilibrted for 10 min. Then the bove procedure ws followed Sttisticl nlysis Anlyses were done in triplicte unless otherwise stted. Results were nlyzed by using sttisticl nlysis softwre system (SPSS Version 12.0, SPSS Inc., IL). Differences mong smples or tretments were compred by using lest significnt difference (LSD) test with probbility level (α) of Results nd discussion 3.1. Strch yields nd purity The percent yields nd the residul impurities of strch were given in Tble 1. The yields were very close to the results obtined by Hoover, Rorke, nd Mrtin (1991) for lim ben strch, but lower thn the vlues reported for cerel strches (Xue, Newmn, & Newmn, 1996). Schoch & Mywld (1968) stted tht isoltion of strch from Tble 1 Yields nd residul impurities of strches. Strch source Yield, % b Ash, % d.b. Protein, % d.b. Lipid, % d.b. Borlotti ben 20.61± ± ± ±0.08 White kidney ben 21.68± ± ± ±0.10 Chickpe 27.84±2.13b 0.16 ± ± ±0.14 Vlues re mens of three mesurements ±stndrd devition. Men vlues in the sme column with different letters re significntly different (Pb0.05). b Strch yields were bsed on 100 g dry legume flour. certin legumes is difficult becuse of the highly hydrted fine fiber frction nd lso the high content of insoluble protein which co-settle with strch to give light, loose deposit. No significnt differences were observed between the proximte compositions of the isolted strches (Tble 1). The totl sh, protein, nd lipid contents of ech legume strches were lower thn 0.73%, indicting tht strches were extrcted with high purity Solubility nd swelling chrcteristics of ntive nd modified strches Swelling power nd solubility of the strch smples, determined t 85 C, were given in Tble 2. Compred to their respective ntive sttes, PD reduced the swelling power of ll three legume strches significntly (Pb0.05). Lurentín et l. (2003) stted tht PD cused to prtil depolymeriztion of the morphous regions in strch. Thus, the strch prtilly lost the bility to hold the bsorbed wter (Wng & Wng, 2003). Likewise, CL nd HMT lso decresed the swelling power of ll three legume strches significntly (Pb0.05), compred to their respective ntive sttes. Gunrtne & Corke (2007) stted tht, CL reinforces the structure of strch grnules nd limits wter bsorption by restricting the mobility of strch chins in the morphous region. In the cse of HMT dditionl interctions my hve occurred between mylose mylose nd mylose mylopectin chins which restrict swelling (Olyink, Adebowle, & Olu-Owolbi, 2008). On the other hnd swelling power of the GR white kidney ben nd chickpe strches were not significntly different (PN0.05) from the ntive strches. GR borlotti ben strch ws slightly lower thn its ntive form. Tble 2 shows tht solubility of the three ntive legume strches were not significntly different (PN0.05). Significnt increses in solubility were seen fter PD nd CL process. Solubility of PD strches ws pproximtely 7 9 times higher thn the ntive strches. The sme increse ws lso determined in the solubility of lim ben strches fter PD, which ws explined by n increse in the low moleculr weight liner frctions with hydroxyl groups tht Tble 2 Swelling power nd solubility of ntive nd modified strches. Strch source Swelling power, g/g Solubility, % Borlotti ben Ntive 8.2± ±1.3c PD 0.7±0.3h 77.7 ±5.1 CL 3.9±0.1f 19.1 ±0.2b HMT 6.6±0.1d 7.4 ±0.9cd GR 7.6±0.4bc 3.2 ±0.1de White kidney ben Ntive 7.5±0.4c 9.9±0.9c PD 0.7±0.3h 77.2 ±6.1 CL 4.5±0.1e 20.7 ±0.3b HMT 6.6±0.3d 6.3 ±0.7cde GR 7.4±0.1c 3.7 ±0.1de Chickpe Ntive 7.9±0.1bc 9.3 ±0.6c PD 0.8±0.4h 81.2 ±4.6 CL 3.3±0.1g 18.5 ±0.2b HMT 6.7±0.1d 7.8 ±0.1cd GR 8.1± ±0.1e Vlues re mens of three mesurements ±stndrd devition. Men vlues in the sme column with different letters re significntly different (Pb0.05).

4 D. Güzel, S. Syr / Food Reserch Interntionl 43 (2010) fcilitted solubiliztion in hot wter (Cmpechno-Crrer, Coron- Cruz, Chel-Guerrero, & Betncur-Ancon, 2007). Previous studies indicted tht CL generlly decrese the solubility of strch (Liu, Rmsden, & Corke, 1999; Crmon-Grci, Snchez-River, Méndez- Montelvo, Grz-Montoy, & Bello-Pérez, 2009). It ws thought tht the increse in solubility fter CL in this study ws due to the soluble strch occurring s result of the ddition of 1.0 M NOH during ph djustment step of the modifiction process. Compred to ntive strches, there ws non-significnt trend of decresed solubility of HMT strches. The structurl chnges occurring fter HMT restrict swelling s discussed bove might lso be responsible for the lower solubility. The gretest decrese in solubility ws observed fter GR process. This might be explined by the resistnce of strong mylose mylose crystllites, occurring fter GR tretment, to the wter diffusion nd therefore, converting the strch molecule to less soluble form Geltiniztion prmeters of ntive nd modified strches DSC thermogrms were obtined for ech ntive nd modified legume strches. A distinct endotherm pek ws detected for the ll ntive, HMT, nd CL legume strches. However, no pek ws detected for PD nd GR strches, since PD nd GR tretments depolymerizes strch to such n extent tht polymer crystllites responsible for DSC endotherms were eliminted. The corresponding prmeters of the geltiniztion endotherms of ntive, CL, nd HMT strch re given in Tble 3. Significnt increse (Pb0.05) ws observed in the onset temperture of geltiniztion (T o ) of CL nd HMT strches. As explined bove CL limits wter bsorption nd therefore delyed geltiniztion. Woo & Seib (2002) observed 1 11 C increse in the T o of CL whet, corn, nd potto strches. The increses in T o fter HMT in the current study were smller thn the increses fter CL (Tble 3). Adebowle & Lwl (2003), lso observed only slight increse in T o fter HMT of mucun ben (Mucun pruriens) strch. They stted tht the mylose mylose interction fter HMT reduce the mobility of the morphous region, leding to increse in geltiniztion temperture. After CL there ws non-significnt trend for increse in the geltiniztion tempertures rnge (T c T o ), while HMT led to reduction, which ws only significnt for white kidney ben. Increse in T c T o suggest tht the degree of heterogeneity of crystllites within the grnules of CL strches (Gunrtne & Hoover, 2002). However, decreses in T c T o of the HMT strches indicte tht hydrotherml tretment results in decrese of the destbiliztion effect of the morphous region (Shin et l., 2005; Gunrtne & Hoover, 2002). Compred to the rw strch, the geltiniztion enthlpies (ΔH) of the ll CL strches nd HMT white kidney ben strch decresed significntly (Pb0.05), while the decrese in ΔH of HMT borlotti ben nd chickpe strches were not sttisticlly significnt (PN0.05) (Tble 3). Decrese in ΔH ws lso determined fter CL of whet strch (Woo & Seib, 2002) nd HMT of sweet potto strch (Shin et l., 2005). The decrese in ΔH indictes tht some of the double helices present in the crystlline nd morphous regions of the grnule might be disrupted (Shin et l., 2005) In vitro digestibility profiles of ntive nd modified strches The proportion of the RDS, SDS, nd RS of uncooked ntive nd modified legume strches re shown in Fig. 1. PD nd GR strches hs the gretest RDS (39 69%) which is expected since their grnulr structure hs been lredy disrupted during modifiction nd thus become more susceptible to enzymtic hydrolysis. However, the proportion of RDS frction of uncooked ntive, CL nd HMT strches were only between 2 7%. This implies tht new structurl chnges occurred fter CL or HMT rendering the strch resistnt to α-mylse ttck. Eyru et l. (2009) determined the proportion of RDS, SDS, nd RS frctions of ntive red kidney ben strch s 6.7, 9.1, nd 84.1%, respectively which re quite close to the findings of the current study. In nother study Chung et l. (2009) reported tht the proportion of RDS, SDS, nd RS frctions of ntive pe nd lentil strches were in the rnge of %, %, nd %, respectively. The proportion of SDS nd RS frctions of ntive pe nd lentil strches determined by Chung et l. (2009) re somewht different thn the results obtined in the current study. This might be explined by the differences in the definition of the strch frctions. In this study, SDS ws tken s the strch frction digested between 20 nd 120th min of the in vitro enzymtic hydrolysis, which is the time intervl given by Englyst et l. (1992). However, this rnge ws tken s between 20 nd 180th min in the study of Chung et l. (2009). As shown in Fig. 2, cooking incresed the digestibility of ll strches. The proportion of RDS of ll the cooked strch smples ws determined to be higher thn 72%. However, compred with ntive strches, ll the modifictions pplied tended to decrese the RDS proportion. The highest decrese in RDS ws determined fter GR nd HMT for ll the legume strches studied. CL strches tended to hve lower RS content thn the PD, HMT, nd GR strches. The proportion of SDS nd RS frctions of CL whet strch were determined s 16.9% nd 8.1%, respectively by Woo & Seib (2002), which they re slightly higher thn the proportion of SDS nd RS frctions of CL legume strches used in this study. Recent studies on the proportion of RDS, SDS, nd RS frctions in legume strches were reviewed by Hoover, Hughes, Chung, nd Liu (2010). They stted tht it is difficult to mke meningful comprison of the levels of RDS, SDS, nd RS proportion of legume strch since most of these studies used different digestibility methods vrying in time of hydrolysis nd enzyme sources. As noted in the previous section of this study, both the SDS nd RS frctions of strch hve nutritionl benefits. Therefore, the comprison of the nutritionl qulity between the cooked ntive nd modified strches ws mde on the bsis of totl SDS+RS contents (Tble 4). The totl SDS+RS content of GR nd HMT strches were notbly higher thn the CL nd PD strches. Common structurl fetures of GR nd HMT strches re mylose mylose recrystlliztion, which my implies tht the mylose mylose recrystlliztion is Tble 3 Geltiniztion prmeters of ntive nd modified strches. Strch source T o, C T p, C T c, C T c T o, C ΔH, J/g Borlotti ben Ntive 66.4±0.4c 73.0±1.1c 80.6±0.5c 14.2±0.7b 15.1±0.8 CL 72.6 ± ± ± ±0.4b 10.8 ±0.7b HMT 68.5 ±0.6b 74.4 ±0.7bc 80.6±0.9c 12.1 ±0.9bc 14.7 ±1.4 White kidney ben Ntive 66.2±0.3c 74.1±1.0bc 81.6±1.3bc 15.4± ±1.1 CL 71.9 ±0.6b 81.3 ± ± ± ±1.3c HMT 69.3 ±0.8b 76.1 ±0.7b 83.1±1.1b 13.8 ±1.2b 11.2 ±0.9b Chickpe Ntive 60.9 ±0.6e 67.3 ±0.4e 72.8±0.3e 11.9 ±0.6bc 12.3 ±1.3b CL 67.0 ±0.9c 73.7 ±0.9c 80.9±0.9bc 13.9 ±0.7b 6.3±1.5c HMT 64.1 ±0.4d 69.6 ±0.6d 75.2±0.9d 11.1 ±1.0c 9.3±0.7b Vlues re mens of three mesurements±stndrd devition. Men vlues in the sme column with different letters re significntly different (Pb0.05).

5 2136 D. Güzel, S. Syr / Food Reserch Interntionl 43 (2010) Fig. 1. RDS (rpidly digestible strch), SDS (slowly digestible strch), nd RS (resistnt strch) percentge of uncooked ntive nd modified borlotti ben (), white kidney ben (b), nd chickpe (c) strches. Different letters on top of the brs indicte significnt differences (Pb0.05) in % strch frctions. the most effective prmeter in the formtion of nutritionlly beneficil strch frctions with reduced digestibility. This trend ws lso in greement with the lower solubility of GR nd HMT strches thn the others (Tble 4). Chung et l. (2009) stted tht the mylose mylose interctions, which re much stronger thn those of mylose mylopectin or mylopectin mylopectin, my hve continued to exist fter geltiniztion nd thereby prtly restricting ccessibility of strch chins to the hydrolyzing enzymes. Literture dt lso indictes tht crystl structure nd the grnule surfce properties of strch re the other effective prmeters on strch digestibility (Gunrtne & Hoover, 2002; Tester, Debon, & Sommerville, 2000; Plnchot, Colonn, Gllnt, & Bouchet, 1995). Fig. 2. RDS (rpidly digestible strch), SDS (slowly digestible strch), nd RS (resistnt strch) percentge of cooked ntive nd modified borlotti ben (), white kidney ben (b), nd chickpe (c) strches. Different letters on top of the brs indicte significnt differences (Pb0.05) in % strch frctions. 4. Conclusion The finding from this study shows tht PD, CL, nd HMT limit the swelling power of legume strches. PD nd CL decresed the strch solubility, where GR incresed it significntly. The results of DSC studies showed tht CL tretment disrupts the semi-crystlline structure more thn HMT. Compred with ntive strches, ll the modifictions pplied incresed the nutritionlly beneficil SDS nd RS frctions. The lrgest increse in SDS nd RS frctions ws seen fter GR nd HMT. Dt presented here provide support to tht the structurl chnges occurred fter GR nd HMT re resulted in

6 D. Güzel, S. Syr / Food Reserch Interntionl 43 (2010) Tble 4 Totl SDS+RS contents of cooked ntive nd modified legume strches (% of totl strch). Strch source Borlotti ben White kidney ben Chickpe Ntive 6.7 ±0.6d 11.8±1.1c 12.7±0.9c PD 13.0 ±1.0c 17.8±0.9b 18.9±2.1b CL 10.2 ±0.2c 17.5±2.1b 17.3±1.8b HMT 19.4 ±0.9b 19.7±1.9b 23.2±2.1 GR 28.0 ± ± ±1.9 Vlues re mens of three mesurements ±stndrd devition. Men vlues in the sme column with different letters re significntly different (Pb0.05). restricted ccessibility of strch chins to the hydrolyzing enzymes. Therefore, replcing ntive legume strch with GR or HMT legume strch my be useful in the development of new products with reduced clorie nd slower glycemic response in humns. References AACC, Americn Assocition of Cerel Chemists (2000). Approved methods of the AACC, 10th ed. St. Pul, MN: The Assocition. Adebowle, K. O., & Lwl, O. S. (2003). 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