Palatable and Bio-Functional Wheat/Rice Products Developed from Pre-Germinated Brown Rice of Super-Hard Cultivar EM10

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1 Bioscience, Biotechnology, n Biochemistry ISSN: (Print) (Online) Journl homepge: Pltle n Bio-Functionl Whet/Rice Proucts Develope from Pre-Germinte Brown Rice of Super-Hr Cultivr EM10 Sumiko NAKAMURA, Hikru SATOH & Ken ichi OHTSUBO To cite this rticle: Sumiko NAKAMURA, Hikru SATOH & Ken ichi OHTSUBO (2010) Pltle n Bio-Functionl Whet/Rice Proucts Develope from Pre-Germinte Brown Rice of Super- Hr Cultivr EM10, Bioscience, Biotechnology, n Biochemistry, 74:6, , DOI: / To link to this rticle: Pulishe online: 22 My Sumit your rticle to this journl Article views: 220 View relte rticles Citing rticles: 14 View citing rticles Full Terms & Conitions of ccess n use cn e foun t

2 Biosci. Biotechnol. Biochem., 74 (6), , 2010 Pltle n Bio-Functionl Whet/Rice Proucts Develope from Pre-Germinte Brown Rice of Super-Hr Cultivr EM10 Sumiko NAKAMURA, 1 Hikru SATOH, 2 n Ken ichi OHTSUBO 1;y 1 Fculty of Agriculture, Niigt University, 8050 Ikrshi-ninocho, Nishi-ku, Niigt , Jpn 2 Grute School of Agriculture, Kyushu University, Hkozki, Higshi-ku, Fukuok , Jpn Receive Novemer 17, 2009; Accepte Mrch 1, 2010; Online Puliction, June 7, 2010 [oi: /.90850] It ecme possile to prouce high-qulity n iofunctionl whet/rice re n whet/rice nooles y lening, pre-germinte n cooke rown rice of super-hr cultivr with whet flour. Super-hr rice (SHR) is not suitle for tle rice ecuse of its low pltility. Nevertheless, it ws foun to e suitle s lening mteril for re-mking or noole-mking ue to its hr texture n high content of resistnt strch. We evelope novel rpi germintion metho to improve the qulity n to sve the time neee for germintion. By lening pre-germinte n cooke SHR (30% w/w on ry sis) s rice gel with whet flour (70% w/w on ry sis), the re ecme very soft n ny hrening fter re-mking ws mrkely retre. Similrly, lening pre-germinte n cooke SHR s cooke rice gel with whet flour gve high-qulity nooles with similr texture to tht of urum semolin nooles. The resistnt strch of the SHR-lene re n nooles ws lso mrkely increse. White wxy rice (9%) soke n cooke with the pre-germinte rown rice of SHR (21%) prouce rice gel tht ws very useful s mteril for re-mking n noole-mking y lening with whet flour (70%) to prepre soft, tsty n iofunctionl whet/rice re n whet/rice nooles. Key wors: re; noole; super-hr rice; cooke rice; germintion Whet is the most suitle crop for re mking. Bre is prepre from hr whet flour through process involving scling, ough processing, proofing, king n cooling. 1) Gluten contins hunres of protein components which re present either s monomers or, linke y inter-chin isulfie ons, s oligomers n polymers. 2) High-yieling n low-cost rice is promising crop to prepre re for those people living in the tropicl or semi-tropicl regions. Rice re hs een investigte for the lst 50 yers 3,4) n in mny susequent stuies. 5 14) Gluten is not forme uring ough preprtion s the protein composition n properties of rice re ifferent from those of whet. 5,6) It hs een reporte tht the qulity of re me from 20% rice n 80% whet flour ws cceptle, ut tht of re me from 30% rice n 70% whet ws not cceptle. 6) Morit hs replce prt of the whet flour with un-germinte or germinte rown rice flour for re-mking n reporte tht 10% or 20% replcement gve goo results, while 30% sustitution cuse extremely lower expnsion of the re volume. 9) Steme re is populr in north-estern Asi in plce of levene herth re in USA n Europe. 8) A rice-pulse comintion 10) or the extrusion process 11,15) hs een use to compenste for the lck of gluten in rice re. Vrious gums, surfctnts, hyrophilic polymers, or super-hr whet flour hs een reporte to e effective to improve the ough property of rice flour with less or without ny gluten. 8,16,17) Bre s well s nooles re mjor foostuffs throughout the worl. 3,18 20) Rice nooles is one of the most populr foos in Asi, n high-mylose rice is suitle s mteril for mking nooles. 3) Dietes is one of the life-style iseses, so preventing such iseses is very importnt to support the evelopment of curing technology. Low glycemic inex (GI) foo inhiits the rpi increse of loo glucose. The effects of test cerel rekfsts iffering in the glycemic inex n content of inigestile crohyrtes on y-long glucose tolernce hve een reporte. 21) The use of low GI re in plce of high GI re hs een reporte to e effective for lowering the loo glucose level. 22) Severl stuies hve een reporte on high-resistntstrch rice, 23) n high-mylose n high-ietry-fier rice 24) tht hve een evelope y physicl or chemicl muttion. The super-hr rice cultivr, EM10, ws evelope y Stoh 25) y chemicl muttion (the MNU tretment) t Kyushu University in Jpn. EM10 lcks strch rnching enzyme II, which lowers the mount of short-chin glucns ( egree of polymeriztion lower thn 17) n inuces resistnce to geltiniztion. The mylopectin of EM10 hs more long-chin glucns, mking the texture very hr n non-sticky fter cooking n giving uncceptle pltility s cooke rice. 26) Nevertheless, EM 10 is promising s mteril for such low-gi foos, s re n noole, to prevent ietes, ecuse it contins sustntil mount of resistnt strch even fter cooking. 20) Pre-germinte rown rice (PGR) is prepre y soking the rown rice in wter, which ctivtes glutmte ecroxylse, n the gmm mino utyric ci (GABA) content in pre-germinte rown rice is y To whom corresponence shoul e resse. Tel/Fx: ; E-mil: ohtsuok@gr.niigt-u.c.jp Arevitions: SHR, super-hr rice; PGR, pre-germinte rown rice; GABA, gmm minoutyric ci; GI, glycemic inex; MNU, methyl nitroso ure

3 increse to twice tht in orinry rown rice n ten times tht in white rice. 27,28) The pltility of PGR, is improve compre with orinry rown rice ue to the ctivte enzymes, which prtilly ecompose the strch. This strch ecomposition les to the genertion of sustntil mount of glucose n other oligoscchries, s well s to softening the texture of the cooke rice. The GI vlue of PGR is out 60% tht of orinry white rice, mking it likely to retr the increse of loo sugr fter mel. 22) The evelopment of low GI whet/rice re y using super-hr rice is promising route to prevent people from contrcting ietes. Since the pltility n io-functionlity ws improve y germinting rown rice, super-hr EM10 rice, ws supplemente with whet flour to prouce more suitle s PGR. Germintion in wrm wter for long time cuse microorgnisms to increse rpily, sometimes resulting in, the prolems with hygiene. 28) Moreover, the flvor of cooke PGR eteriortes fter soking for long time. 28) We serche in the present stuy for novel metho to prepre PGR without soking for long time. Preventing the prolems of off-flvor n microorgnism infesttion uring long-term germintion in wrm wter ws investigte y testing novel germintion metho of soking SHR for short time n then grully heting. Mterils n Methos Mterils. EM10 super-hr rice n Hoshiyutk high-mylose rice were cultivte in n experimentl fiel of Kyushu University in Kognemochi wxy rice n Milkyqueen semi-wxy rice were cultivte in n experimentl fiel of Crop Science Institute t Tsuku in Koshihikri high-qulity rice ws cultivte in n experimentl fiel of Hokuriku Center in Joetsu in The whet flour for re mking, Cmelli (Nisshin Flour Milling Co.), ry yest (Pioneer Plnning Co.), sugr (Nisshin Seito Co.), soium chlorie (Ajinomoto Co.), eslte utter (Yukijirushi Co.) n skim milk (Moring Milk Inustry Co.) were commercilly ville proucts. Preprtion of the rice smples. The rown rice ws polishe y n experimentl friction-type rice milling mchine (Ymmotoseiskusyo Co., Tenoh, Jpn) to milling yiel of 90 91%, n its moisture content ws juste to 13.5% in n rtificil environment room (Snyo Meicsystems Co., Tokyo, Jpn). Rice flour ws prepre y n SFC-S1 cyclone mill (Uy, Fort Collins, USA) with screen of 1-mm imeter pore size. Mesurement of the psting properties of the rice n whet flour smples lene with rice flour. The psting properties of the rice flour n whet flour smples lene with vrious types of rice flour were mesure with n RVA Super 4 rpi-visco-nlyzer (New-port Scientific, Wrriewoo, Austrli). A progrmme heting n cooling cycle ws followe s outline in the proceure of Toyoshim et l. 29) EM10, Hoshiyutk, Koshihikri n Kognemochi were use s smples to compre the vrious rice cultivrs. The Cmelli smple of whet flour ws use s control. In orer to clrify the chnge in psting properties y lening whet n rice uner ifferent cooking conition, the lens of whet (70%) n 5-min-cooke SHR (30%), whet (70%) n 35-min-cooke SHR (30%), n whet (70%) n moe 2-cooke SHR (30%) were sujecte to the RVA mesurements. In the cse of the 5-min-cooke rice, it ws hete from room temperture to 97 C for 1 min n mintine for 3 min t 97 C, efore eing kept for 1 min in the pprtus fter heting. In the cse of the 35-min-cooke rice, it ws hete from room temperture to 97 C for 10 min n mintine for 15 min t 97 C, efore eing kept for 10 min in the pprtus fter heting. Cooke rice ws then lyophilize n mixe with whet flour. Whet/Rice Bre from Super-Hr Rice 1165 Rice cooking n preprtion of the geltinize rice pste. Ech type of mille rice (22.5 g; Koshihikri, Hoshiyutk, Kognemochi n Milkyqueen) ws mixe with the rown SHR rice (52.5 g), wter (300 ml) ws e, n the mixture incute t 45 C for 30 min y Titec wter th with Personl ll shker, efore eing soke t 37 C for 2 h in the experimentl MIR-262 incutor (Snyo). The pregerminte rown rice (0.2 mm of sprouts) n mille rice grins were then geltinize y cooking with the experimentl cooking system equippe with therml controller (Tkesho Scientific Co., Niigt, Jpn). The cooking conitions were s follows: Moe 1: Rice grins were hete t 4.77 C/min to 60 C, then t 2.82 C/min from 60 Cto80 C, n finlly t 0.85 C/min from 80 Cto97 C, efore eing mintine 97 C for 20 min. Moe 2: Rice grins were hete t 2.08 C/min to 60 C, 1.22 C/min from 60 C to 80 C, n 0.68 C/min from 80 C to 97 C, then mintine t 97 C for 35 min. Moe 3: Rice grins were hete t 3.48 C/min to 60 C, 0.90 C/min from 60 C to 80 C, n 1.70 C/min from 80 C to 97 C, then mintine t 97 C for 20 min. The cooke rice grins were then mshe with THM 500 sticklener (Tescom Co., Tokyo, Jpn). Mesurement of the physicl properties of the cooke rice grins. The physicl properties of the cooke rice grins were mesure y the high-compression/low-compression metho with Tensipresser (My Boy System, Tketomo Electric Co., Tokyo, Jpn) uner the sme conitions s those escrie in our previous stuy. 30) Bre-mking. Bse upon the recipe for whet re, 30% of ech rice flour smple n 70% of whet flour were lene n sujecte to the re-mking process escrie next. The recipe for the re ws s follows: 175 g of whet flour (Cmelli), 75 g (ry mtter) of rice pste, 17 g of sucrose, 8.5 g of skim milk power, 15 g of slt-free utter, 1.5 g of NCl, 2.7 g of commercil rie yest, n n pproprite mount of e-ionize wter. Wter in the ough for remking is very importnt s plsticizer, solvent, genertor of gluten 1) n to just the physicl properties of the ough n susequent re. We selecte fter the mny experiments, s reporte in our previous stuy, the most suitle mount of wter for ech rice smple to mke re. 14) It ws foun eneficil in the present stuy to the pre-germinte n geltinize rice to the whet flour for improving the re texture n retrogrtion. After mesuring the moisture content of the geltinize rice gel, we e to it (3=7 100Þ% of whet flour on ry mtter sis, efore ing suitle mount of wter uring kneing. The mount of wter e for ech rice cultivr ws etermine y mesuring the texture of the ough with Tensipresser s reporte in our previous stuy. 14) Ech ough smple ws then ke with n SD-BT103 utomtic home kery mchine (Pnsonic Co., Kom, Jpn) se on the stright ough proceure. The time set for re-mking, involving ough processing, proofing, n king, ws 5 h. Preprtion of whet/rice nooles. Bse on the preprtion metho for whet nooles, to 175 g of strong whet flours (Cmelli) ws e 75 g of ech kin of geltinize rice gel ( len of 52.5 g of cooke pre-germinte SHR rown rice n 22.5 g of cooke white rice, ech on ry sis) n 10 g of soium chlorie, n the ough knee for 45 min with n SD-BH101 utomtic re kery system (Pnsonic, Kom, Jpn). The finl moisture content of the ough ws juste to 40%. Therefter, the ough ws stoo overnight in refrigertor. The ough ws then put twice through the roll (100 mm in with n 2 mm of clernce) n finlly cut y the le to with of 2.2 mm. The nooles were hete for 2 min in oiling wter n then coole for 1 min in wter t 20 C. These nooles were then mesure for their physicl properties, chemicl components n eting qulity. Mesurement of the moisture content of the ough n re. Ech ough smple n re (2 g) were put in n luminum cup n rie t 135 C for 3 h in n oven. Mesurement of the physicl properties of the ke re. The physicl properties of the re crum were mesure y the continuous progressive compression (CPC) metho with My Boy

4 1166 S. NAKAMURA et l. Tensipresser (Tketomo Electric Co., Tokyo, Jpn) uner the sme conitions s those use in our previous stuy. 14) Ech re smple ws 3 cm squre n 1.5 cm in thickness. The mesurements were me five times. The firming egree of re is efine s the rtio of re toughness on the 4th y fter preprtion to the re toughness one y fter preprtion t room temperture (20 C). Mesurement of the physicl properties of the nooles. The physicl properties were gin mesure y the continuous progressive compression metho with the Tensipresser. 14,30) A 15 g mount of nooles ws put into the luminum smple cup (4.4 cm in imeter, 1.1 cm in height) n the nooles were sujecte to the mesurement process. The ite spee ws 3 mm/s, ite repeting ws 5 times, istnce ws 35 mm, n clernce ws 1 mm. Mesurements were tken five times, n the t were sttisticlly nlyze y the softwre provie with the Tensipresser. Specific volume of the re. The volume of the re ws mesure y the plnt sees metho. Three loves of re for ech smple were use n men vlue n stnr evition were clculte for ech smple. Mesurement of the resistnt strch. The resistnt strch in the smple ws mesure ccoring to the AOAC metho y resistnt strch ssy kit (Megzyme, Wicklow, Ireln). Ech smple (100 mg) ws igeste y pncretin n myloglucosise, n glucose ws mesure y spectrophotometry t 510 nm. Mesurement of glucose n glutmic ci. To lyophilize smple (0.1 g) ws e 1 ml of 60% ethyl lcohol n the glucose ws extrcte y rottion t 20 C for 1 h. 31) The solution ws centrifuge (1500 g for 15 min) n the resulting superntnt ws use s the smple solution for mesurement. The glucose content in the smple solution ws mesure y the NADPH enzyme ssy metho with glucose ssy kit (Roche, Drmstt, Germny). The glutmic ci content ws mesure y the phormzn enzyme ssy metho with glutmic ci ssy kit (Roche, Drmstt, Germny). Sttisticl nlyses. All the results were sujecte to sttisticl nlysis y Tukey s multivrite metho provie in Excel Sttistics (ver. 2006, Microsoft Corportion, Tokyo, Jpn). Results n Discussion Physicl properties of the cooke rice grins Mesurement of the physicl properties of the cooke rice grins y the low-compression/high-compression metho 30) with the Tensipresser showe the SHR grins (EM10) to hve extrorinrily hr n non-sticky properties (H1, 280 gw/cm 2 ; S1, 1.3 gw/cm 2 ) compre with wxy rice (Kognemochi: H1, 39 gw/cm 2 ; S1, 8.3 gw/cm 2 ), low-mylose rice (Milkyqueen: H1, 71 gw/cm 2 ; S1, 13.9 gw/cm 2 ), premium Jponic rice (Koshihikri: H1, 78 gw/cm 2 ; S1, 11.2 gw/cm 2 ) n even hr inic/jponic hyri rice (Hoshiyutk: H1, 92 gw/cm 2 ; S1, 2.9 gw/cm 2 ). Nishi n others hve reporte 25) SHR to hve fewer rnche short glucns n more long chins in the mylopectin of the strch. SHR is therefore resistnt to geltiniztion n when cooke is very hr n non-sticky. 24,26) Since cooke SHR rice ws hr n tough, it seeme tht SHR coul e suitle for use s mteril for whet/rice re or whet/rice nooles to compenste for the wek ough lene with rice. Morris hs reporte, 19) the psting properties y RVA re goo inices for the processing suitility of the whet cultivrs. Koshihikri showe the typicl RVA profile of Jponic rice, which reveling high pek viscosity n high rek-own. Milkyqueen, lowmylose rice, showe slightly higher pek viscosity n lower finl viscosity thn Koshihikri. Hoshiyutk, high-mylose rice, showe slightly lower pek viscosity n higher finl viscosity. Kognemochi, wxy rice, showe mrkely lower pek viscosity n lower finl viscosity. EM10, SHR, showe lower pek viscosity n mrkely higher finl viscosity. As shown in Fig. 1A, the rekown of SHR, EM10 ws very low, which mens tht the geltinize strch grnule ws resistnt to reking own y stirring. These psting properties re similr to other highmylose or high-resistnt-strch rice. 23,24) In ition to the hr n tough properties of the cooke rice grins lrey mentione, it seeme tht EM10 woul e suitle for lening with whet flours to mke whet/rice re or whet/rice nooles, ecuse its geltinize strch gel ws tough n woul mintin firm ough texture. The psting properties of the lene whet/rice flour smples (7:3, y weight) were mesure y RVA. Tle 1 shows the psting properties of whet/rice flour smples lene with glutinous rice (Kognemochi) or SHR (EM10) were similr to those of whet flour. We compre the psting properties of the whet/rice flour smples lene with rw rice flour n cooke rice gel. As shown in Tle 1, ll the rice smples with whet flour lene with the cooke rice gel n not s the rw flour showe lower finl viscosity, which is n inictor of the retrogrtion. Furthermore, s shown in Tle 1, comprison mong the sme rice cultivr gve setck vlue for smple 8 (geltinize EM10) lower thn tht for smple 3 (rw EM10). Rice re hs the prolem of its texture ecoming hrer 3 4 ys fter re-mking, 6,14) so tht cooke rice woul e more suitle thn rw rice to reuce the retrogrtion of strch fter re-mking. Psting properties of the whet flour smples lene with vrious cooke rice gels The psting properties of the whet flour smples lene with rice gel cooke uner the ifferent conitions were mesure y RVA. As shown in Fig. 1B, the finl viscosity, n inictor of the egree of retrogrtion, of the smples ecme lower in the orer of cooking conitions, c n. The longer the rice cooking time ws, the lower the finl viscosity ecme. This shows why the cooke rice gel woul e more suitle thn rw rice flour s mteril. Cooke rice woul e etter thn rw rice to prevent hrening of the whet/rice re fter re-mking s the strch of the cooke rice geltinize well. Moe 2 cooking ws not only useful to rpily prepre the pre-germinte rown rice ut lso provie properly cooke rice s mteril to inhiit hrening of the whet/rice re. Psting properties of the rice flour from vrious cultivrs The psting properties of the vrious rice flour smples mesure y RVA re shown in Fig. 1A. As Resistnt strch in the cooke rice grins SHR h mrkely higher mount of resistnt strch thn the other rice grins s shown in Fig. 2. The mount of resistnt strch in cooke pre-germinte

5 Whet/Rice Bre from Super-Hr Rice 1167 A Viscosity (RVU) c e f Time (min) B c Viscosity (RVU) Time (min) Fig. 1. Psting Properties of the Vrious Types of Rice Flour. A, Comprison of vrious rice cultivrs., EM10;, Hoshiyutk; c, Koshihikri;, Cmelli (whet); e, Milkyqueen; f, Kognemochi. B, Chnge in psting properties y lening rice cooke for ifferent times., 70% whet n 30% 5-min-cooke SHR;, 100% whet; c, 70% whet n 30% 35-min-cooke SHR;, 70% whet n 30% moe 2-cooke SHR. SHR rice ws 8.3%, this eing out 4 times tht in high-mylose rice, Hoshiyutk (2.1%) n 8 times tht in premium Jponic rice, Koshihikri (0.95%). SHR showe very high mount of resistnt strch even fter cooking y lening with cooke soft rice grins. Yng hs reporte the strch properties of mutnt rice which ws rich in resistnt strch. 23) Our SHR showe higher content of resistnt strch fter cooking thn the highresistnt-strch rice, Rs 111, reporte y Yng et l. 23) The improve metho etermining the resistnt strch content of rice n rice proucts showe tht the resistnt strch ecrese fter mking rice crckers. 32) Although germintion n cooking ecreses the resistnt strch in the rice grins, 20) SHR mintine very high mount of resistnt strch fter germintion n cooking. The use of low-gi re in the plce of high- GI re hs een reporte to e effective to lower the loo glucose level. 26) Bre from whet n SHR therefore seems to e promising for the prevention of ietes. Germintion of SHR Pre-germinte rown rice is usully prepre y soking rown rice grins overnight t C. 27) This tkes long time, such s 12 h or 18 h, llowing microorgnisms to consierly increse n eteriorting the qulity of the germinte rown rice in terms of its flvor n texture. 28) We therefore serche for novel germintion metho. After soking rown SHR rice grins for 30 min t 45 C, they were next soke for two hours t 37 C, n then cooke uner the three conitions shown in Fig. 3. Brown rice germinte well in the cse of moe 2 s shown in Fig. 3. Physicl properties of the cooke pre-germinte rown rice grins re shown in Tle 2. The germinte rown rice grins prepre y moe 2 cooking showe higher H1 lnce (the rtio of stickiness S1 to hrness H1 ws y low-compression test with the Tensipresser) compre with the figures for moe 1 (0.0026) n moe 3 (0.0025) n higher H2 lnce (the rtio of stickiness S2 to hrness H2 ws y high-

6 1168 S. NAKAMURA et l. Tle 1. Psting Properties of Whet n Blene Flour No Mx.visc Min.visc Brek-own Finl.visc Setck Pek Time (RVU) STDEV (RVU) STDEV (RVU) STDEV (RVU) STDEV (RVU) STDEV (min) STDEV Whet (Cmelli) 2 70% whet n 30% Koshihikri white rice flour 3 70% whet n 30% EM10 white rice flour 4 70% whet n 30% Kognemochi white rice flour 5 70% whet n 30% Hoshiyutk white rice flour 6 70% whet n 30% Milkyqueen white rice flour 7 70% whet n 30% Koshihikri geltinize white rice flour 8 70% whet n 30% EM10 geltinize white rice flour 9 70% whet n 30% Kognemochi geltinize white rice flour 10 70% whet n 30% Hoshiyutk geltinize white rice flour 11 70% whet n 30% Milkyqueen geltinize white rice flour 12 70% whet n 30% EM10 geltinize pre-germinte rown rice flour 13 70% whet n 30% Koshihikri geltinize pre-germinte rown rice flour 14 70% whet, 21% EM10 geltinize pre-germinte rown rice flour n 9% Milkyqueen geltinize white rice flour 15 70% whet, 21% EM10 geltinize pre-germinte rown rice flour n 9% Kognemochi geltinize white rice flour 16 70% whet, 21% EM10 geltinize pre-germinte rown rice flour n 9% Koshihikri geltinize white rice flour 17 70% whet, 21% EM10 geltinize pre-germinte rown rice flour n 9% Hoshiyutk geltinize white rice flour Resistnt strch (%) A B C D E Smple Fig. 2. Resistnt Strch in the Cooke Pre-Germinte Brown Rice. A, Milkyqueen geltinize pre-germinte rown rice. B, Kognemochi geltinize pre-germinte rown rice. C, Koshihikri geltinize pre-germinte rown rice. D, Hoshiyutk geltinize pre-germinte rown rice. E, EM10 geltinize pre-germinte rown rice. compression test with the Tensipresser) compre with the figures for moe 1 (0.013) n moe 3 (0.027). Presoking the rown rice for 30 min t 45 C ws effective for soring lrge mount of wter into the rown rice grins n for ctivting the vrious enzymes. The reson for moe 2 showing the est germintion is tht the temperture rose slowly from 30 Cto60 C, so tht the vrious enzymes necessry for germintion remine ctive for longer thn uner the other conitions. It took less thn 7 h with our presoking n moe 2 cooking which we cll the rpi germintion metho. We hve pointe out in the introuction tht it tkes h for the usul germintion of rown rice, which results in microorgnism infesttion n the genertion of n offflvor. Such infesttion n off-flvor genertion i not occur s result of our rpi germintion. Furthermore, rown rice grins pre-germinte y our rpi metho contine more glucose (4.24 g/100 g), glutmic ci (24.26 mg/100 g) n resistnt strch (7.84 g/100 g) thn those (3.81 g/100 g, 10.6 mg/100 g, n 7.68 g/100 g, respectively) in rown rice grins pre-germinte y the orinry soking metho (18 h). We o not hve to chnge the soking wter so tht our PGR contine more glucose n glutmic ci ecuse it i not lose those tsty sustnces. Suitle conitions for the preprtion of whet/rice re After eing pre-trete (45 C for 30 min n 37 C for 120 min), 52.5 g of SHR grins n 22.5 g of mille rice grins of ech cultivr were cooke with 300 ml of wter for 2 h. The cooke rice ws lene with 175 g of whet flour fter cooking. In orer to prepre the highlyexpne re, it ws necessry to the most suitle mount of wter ccoring to ech rice cultivr.

7 Whet/Rice Bre from Super-Hr Rice Temperture ( C) Cooking time (min) ; Moe 1 ; Moe 2 ; Moe 3 Rice cultivr is EM10 Fig. 3. A Cooking Conitions for Rpi Germintion n Photogrphs of the Pre-Germinte Brown Rice Grins. B c e Fig. 4. Cross Section of the Whet/Rice Bre Smples. A, Whet/rice re (70% whet n 30% rice)., 100% whet (Cmelli);, 70% whet n 30% uncooke pre-germinte rown SHR; c, 70% whet n 30% uncooke rown SHR;, 70% whet n 30% uncooke white SHR; e, 70% whet n 30% cooke pre-germinte rown SHR. B, Whet/rice nooles. 70% whet, 21% cooke pre-germinte rown SHR, n 9% cooke white wxy rice. Tle 2. Physicl Properties of Coooke Pre-Germinte Brown Rice Grins Cooking conitions Surfce hrness (H1) Low compression test (25%) High compression test (90%) Surfce stickiness (-H1) Blnce (-H1/H1) Overll hrness (H2) Overll stickiness (-H2) Blnce (-H2/H2) [gw/cm 2 ] SD [gw/cm 2 ] SD SD [gw/cm 2 ] SD [gw/cm 2 ] SD SD Moe Moe Moe Physicl properties of cooke rice grins were mesure y the high-compression/low-compression metho y Tensipresser. The results of mesurements reporte in our previous stuy 14) were use to select the most suitle mount of wter to e e to the len of whet flour n cooke rice for ech rice cultivr lene. The etermine mounts of wter were 88 ml for EM10 (75 g of SHR), 38 ml for Koshihikri, 44 ml for Kognemochi, 59 ml for Hoshiyutk n 48 ml for Milkyqueen. Hr rice such s SHR or Hoshiyutk require lrger mount of wter thn other soft-types of rice flour. Effect of germintion n cooking on the whet/rice re Cross sections of the vrious kins of re prepre from whet (70%) n vrious types of rice flour (30%, white rice, rown rice, pre-germinte rown rice or cooke n pre-germinte rown SHR) re shown in Fig. 4A. The lof volume ws highest in the cse of cooke pre-germinte rown rice (the e, specific volume ws 3.6), followe y uncooke white rice (, 3.4), uncooke rown rice (c, 3.3), n uncooke pre-germinte rown rice (, 3.0). Orinry whet re prouce greter specific volume of 4.0 (). The lph-mylse ctivity of white rice is lower thn tht of rown rice, mking the stronger ough texture of white rice thn of rown rice yiel the higher re volume. In the cse of cooke pre-germinte rown rice, lph-mylse is enture n the geltinize SHR strch gives the most suitle ough properties compre with the other uncooke SHR ough, this leings to the improve specific volume of the lof.

8 1170 S. NAKAMURA et l. An exmple of whet/rice nooles is shown in Fig. 4B. High-mylose rice hs een reporte to e more suitle thn low-mylose rice for rice nooles ue to its lower stickiness. 3) As shown in Fig. 4B, whet/rice nooles prepre from 70% of whet lene with 21% of SHR n 9% of wxy rice resulte in high cceptility ue to the low-stickiness n elstic texture. A Blening of two rice cultivrs Although SHR is suitle for lening with whet in terms of re-mking, its pltility s cooke rice is inferior to Koshihikri, the premium rice in Jpn. In orer to improve the pltility of the whet/rice re, we serche for the most suitle len of the cooke rice gel with the cooke pre-germinte EM10 SHR rown rice. As shown in Tle 1, lening 9% of the cooke white rice gel of Kognemochi (wxy rice) with 21% of the cooke pre-germinte EM10 rown rice gel n 70% of whet flour, improve the psting properties. It ws pprent tht the pek viscosity ecme higher n tht the ifference etween the finl viscosity n minimum viscosity ecme lower compre with using 30% of cooke pre-germinte EM10. We scertine improvements of to the tste n texture of the whet/rice re y lening 9% of wxy rice with 21% of SHR. Physicl properties of the whet/rice re The physicl properties of the vrious kins of whet/ rice re re shown in Fig. 5A (smples A G). Toughness inictes the work of stress ginst pressure n correspons to the hrness of the re or noole. Compre with orinry whet re, SHR lene re h hrer texture s shown in Fig. 5A. Smples D, E, F n G in Fig. 5A ll show lower toughness thn tht of smple B, mening tht the lowsetck smples in the RVA nlysis woul le to softer whet/rice re (Tle 1 n Fig. 5A). The specific lof volume of whet re (smple A) ws 4.2, EM10 (smple B) ws 3.3, 30% Koshihikri (smple C) ws 3.7, Kognemochi (smple D) ws 3.6, Milkyqueen (smple E) ws 3.7, 9% Koshihikri (smple F) ws 3.7, n Hoshiyutk (smple G) ws 3.8. Accoring to Hung n Preston, 8) Asin consumers prefer softer tsting re for which the crum mouthfeel chrcteristics re highly importnt. The ition of soft white rice type, Koshihikri, Milkyqueen, Kognemochi or Hoshiyutk, significntly improve the physicl properties resulting in texture comprle with tht of whet re or even slightly softer. Firming egree of the re It hs een reporte tht rice re or whet/rice lene re tens to go stle very rpily, limiting its istriution. 3) We mesure the re hrness on 4th y fter re-mking. As shown in Fig. 5A (smples H N), the whet/rice re smples (K, L, n M, lene with soft rice) h lower toughness thn whet re. In prticulr, smple L (Kognemochi) h remrkly soft texture compre with whet re. Smple I (SHR) showe lower egree of firming (the rtio of toughness fter one y to tht of fter 4 ) thn whet re. Although whet/rice re tens to hren mrkely B Toughness [gw cm/cm^2] 7.00E E E E E E E E+00 Smples compre with whet re, Tkno hs reporte tht pre-geltinize rice resiste firming. 6) It ws clrifie in the present stuy tht lene pre-germinte rown rice with whet fter cooking ws effective for re mking to prevent hrening, even in the cse of SHR. A B C D E F Smples Fig. 5. Physicl Properties of Whet/Rice Bre n Whet/Rice Nooles. A, Whet/rice re. Whet/rice re ws prepre from lene flour (70% of whet n 30% of rice). A, whet re; B, geltinize pre-germinte rown rice (30% EM10); C, geltinize pre-germinte rown rice (30% Koshihikri); D, geltinize pre-germinte rown rice (21% EM10) lene with geltinize white rice (9% Milkyqueen); E, geltinize pre-germinte rown rice (21% EM10) lene with geltinize white rice (9% Kognemochi); F, geltinize pre-germinte rown rice (21% EM10) lene with geltinize white rice (9% Koshihikri); G, geltinize pre-germinte rown rice (21% EM10) lene with geltinize white rice (9% Hoshiyutk); H, whet re (4 th y fter re-mking); I, geltinize pre-germinte rown rice (30% EM10) (4 th y fter re-mking); J, geltinize pre-germinte rown rice (30% Koshihikri) (4 th y fter re-mking); K, geltinize pre-germinte rown rice (21% EM10) lene with geltinize white rice (9% Milkyqueen) (4 th y fter re-mking); L, geltinize pre-germinte rown rice (21% EM10) lene with geltinize white rice (9% Kognemochi) (4 th y fter remking); M, geltinize pre-germinte rown rice (21% EM10) lene with geltinize white rice (9% Koshihikri) (4 th y fter re-mking); N, geltinize pre-germinte rown rice (21% EM10) lene with geltinize white rice (9% Hoshiyutk) (4 th y fter re-mking)., ifferent letters show significnt ifference (5%). B, Whet/rice nooles. A, 100% whet; B, 70% whet n 30% EM10 geltinize pre-germinte rown rice; C, 70% whet n 30% Koshihikri geltinize pre-germinte rown rice; D, 70% whet, 21% EM10 geltinize pre-germinte rown rice n 9% Milkyqueen geltinize white rice; E, 70% whet, 21% EM10 geltinize pre-germinte rown rice, n 9% Kognemochi geltinize white rice; F, 70% whet, 21% EM10 geltinize pregerminte rown rice, n 9% Hoshiyutk geltinize white rice.,, ifferent letters show significnt ifference (5%).

9 Whet/Rice Bre from Super-Hr Rice Resistnt strch (%) c c Resistnt strch (%) c 0 A B C D E F G Smples Fig. 6. Resistnt Strch in the Bre. A, 100% whet; B, 70% whet n 30% EM10 geltinize pregerminte rown rice; C, 70% whet n 30% Koshihikri geltinize pre-germinte rown rice; D, 70% whet, 21% EM10 geltinize pre-germinte rown rice, n 9% Koshihikri geltinize white rice; E, 70% whet, 21% EM10 geltinize pre-germinte rown rice, n 9% Hoshiyutk geltinize white rice; F, 70% whet, 21% EM10 geltinize pre-germinte rown rice, n 9% Kognemochi geltinize white rice; G, 70% whet, 21% EM10 geltinize pre-germinte rown rice, n 9% Milkyqueen geltinize white rice;, ifferent letters show significnt ifference (5%). Physicl properties of the whet/rice nooles Rice nooles re populr rice proucts in Asi n re usully prepre from high-mylose rice flour. 3) An exmple of whet/rice nooles is shown in Fig. 4B n the physicl properties of the vrious kins of whet/ rice noole re shown in Fig. 5B. Hemvthy n Bht hve reporte tht rice nooles prepre from fine flour were too soft n sticky n lcke firmness, while those from intermeite flour h the esire softness, smooth surfce n firmness. 32) Both firmness n smoothness of the ough re necessry in the cse of nooles. Smples D n E h similr texture to tht of orinry whet noole (smple A). These smples revele suitle firmness n smoothness, while smples B n C were too soft n sticky. A sensory test in our lortory showe the sme tenency s the results of the physicl property test (t re not shown). It ws foun tht the physicl properties of the whet/rice nooles were significntly improve to out the sme level s tht of whet nooles y comining cooke pregerminte SHR (21%) with cooke soft white rice (9%) such s Milkyqueen or Kognemochi. The toughness of the oile whet/rice nooles y the CPC test represents the strength of the noole structure ginst the continuous stepwise compression. Blening the wellgeltinize low-mylose rice strch with whet my therefore re-inforce the structure more effectively thn with less-geltinize high-mylose rice strch in terms of the lene properties. As shown in Tle 1, the setck vlues for smple numers 12, 13, n 17 (B, C n F in Fig. 5B) re higher thn those for smple numers 14 n 15 (D n E in Fig. 5B). It seems tht the setck vlues cn e goo inices for the physicl properties of the whet/rice nooles. Resistnt strch of the whet/rice re n whet/ rice nooles As shown in Fig. 6, the resistnt strch content increse to 2.65% in the cse of smple B, while smple A contine only 1.12%. Even fter lening 9% of cooke white rice gel, the re contine % of resistnt strch. Resistnt strch is not igeste in the smll intestine uring the igestion process. It hs een reporte tht it is useful to prevent oesity, ietes n colonic cncer. 33) Our whet/rice re from SHR is promising not only s tsty re ut lso s the helth-oriente re. In the cse of whet/rice nooles, resistnt strch ws 1.8 (100% EM10), 1.5 (21% EM10 n 9% Koshihikri), 1.6 (21% EM10 n 9% Hoshiyutk), 1.3 (21% EM10 n 9% Kognemochi) n 1.6 (21% EM10 n 9% Milkyqueen) times higher thn tht of orinry whet nooles s shown in Fig. 7. SHR seems promising s oth mteril for re n lso for nooles. Moreover, our re n nooles contine mny tsty sustnces ecuse the short soking time for germintion without chnging the soking wter prevente the loss of such wter-solule components s glucose n glutmic ci. It is necessry for us to try to increse the lening rtio of EM10 SHR to enhnce the io-functionlity without ny eteriortion of the pltility of such rice proucts s re n nooles. Conclusions A B C D E F Smples Fig. 7. Resistnt Strch in Vrious Nooles from 70% Whet, 21% EM10 Geltinize Pre-Germinte Brown SHR, n 9% Geltinize White Rice., whet nooles (100% Cmelli);, 70% whet n 30% EM10 geltinize pre-germinte rown rice; c, 70% whet n 30% Koshihikri geltinize pre-germinte rown rice;, 70% whet, 21% EM10 geltinize pre-germinte rown rice, n 9% Milkyqueen geltinize white rice; e, 70% whet, 21% EM10 geltinize pre-germinte rown rice, n 9% Kognemochi geltinize white rice; f, 70% whet, 21% EM10 geltinize pregerminte rown rice, n 9% Hoshiyutk geltinize white rice. Cooke pre-germinte SHR rown rice ws e to whet flour to improve the qulity of lene whet/rice re n nooles. Resistnt strch in the re ws mrkely more when SHR ws e. Suitle soking n cooking conition were selecte to rpily prepre high-qulity pre-germinte SHR rown rice. It ws foun fter lening SHR with whet tht cooking n sufficient geltiniztion of the rice strch ws effective to improve the texture n to retr hrening fter the

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