Therml nd Funtionl Chrteriztion of Strh from Argentinen Corn 1 K. Seethrmn, 2 A. Tziotis, 3 F. Borrs, 4 P. J. White, 3,5 M. Ferrer, 4 nd J. Routti 4 ABSTRACT Cerel Chem. 78(4):379 386 Sreening essions in germplsm nk ids in the identifition of plnts with unusul properties rnging from gronomi trits to funtionl nd ompositionl trits of the seed itself. Results from this study onfirm the presene of wide vrition in the therml nd funtionl properties of strh from severl lndres of orn in the Argentinen germplsm. Therml properties of strh mesured using differentil snning lorimetry (DSC) identified severl orn lndres with properties of potentil ommeril interest. The psting nd texturl properties of gels otined from strh of different orn lndres lso exhiited onsiderle vriility. The degree of vrition in therml nd funtionl properties of orn reported in this study is omprle to the therml properties of strh from severl other rop speies. These orn res show promise for further regenertion to rete inred lines with unusul trits. The potentil for further improvement of orn res exists not only sed on therml properties, ut diretly for speifi funtionl ttriutes s well. Correltion nlyses suggest tht the vriility in therml nd funtionl ttriutes re funtion of mylose ontent, grnule size distriution nd, possily, differenes in the struturl mkeup of mylose nd mylopetin. The strong orreltion oserved etween the therml properties nd psting nd texturl properties will llow for the estimtion of strh properties from smll smple sizes. 1 Journl pper No. J-19016 of the Iow Agriulture nd Home Eonomis Experiment Sttions, Ames, Projet No. 3547, nd supported y Hth At nd Stte of Iow funds. Also supported y NRI Competitive Grnts Progrm, United Sttes Deprtment of Agriulture, wrd numer 98355036371, nd the Iow Corn Promotion Bord. 2 Dept. of Food Siene, The Pennsylvni Stte University, University Prk, PA. 3 Dept. of Food Siene nd Humn Nutrition, Iow Stte University, Ames, IA. 4 EEA Pergmino INTA, CC31, 2700 Pergmino, BA, Argentin. 5 Corresponding uthor. E-mil: pjwhite@istte.edu Phone: 515-294-9688. Fx: 515-294-8181. Pulition no. C-2001-0601-02R. 2001 Amerin Assoition of Cerel Chemists, In. Qulity speifitions of orn for food nd feed uses re diverse nd exting. Ahieving the qulity ttriutes for different uses trditionlly hs een omplished y using rnge of posthrvest proessing tehniques suh s milling or modifying strh nd proteins. Breeding nd geneti tools n e used effetively to hieve severl end-use qulity ttriutes. Inorporting unusul trits from exoti germplsm mterils into the nrrow germplsm se ommerilly grown y the griulturl industry worldwide is nother lterntive. Pst ttempts to inorporte tropil germplsm into existing reeding progrms hve hd little suess (Goodmn 1985), primrily due to the lk of informtion out the gronomi, physiologil, pthologil, nd other potentilly useful trits. Further hrteriztion of the germplsm mterils, therefore, is essentil to fully utilize their potentil. The Germplsm Enhnement of Mize (GEM) projet, oordinted through United Sttes Deprtment of Agriulture (USDA) reserhers t Iow Stte University, is one suh ttempt to hrterize nd identify trits relting to strh, protein, or oil ontent nd omposition. Our lortory hs een involved tively in this projet for severl yers nd hs identified severl orn lines with unusul strh nd oil properties tht re eing further evluted nd rossed with Iow orn lines. The identifition of unusul strh therml properties is sed on dtse otined from sreening norml orn strhes over severl yers; summry of those properties is listed in Tle I. The Mize Ative Germplsm Bnk t Pergmino, Argentin, hs olleted more thn 2,500 essions of different lndres of orn nd lssified them into 44 res. The diversity in the orn germplsm in Argentin is extensive euse of the wide vrition in the ltitude nd ltitude within the ountry. To mximize the enefits of this diversity in orn res, omprehensive ssessments of their hrteristis nd trits re neessry. A oopertive reserh effort etween PROCIM (Mize Qulity Reserh Projet) nd USDA-Agriulturl Reserh Servie (ARS) ws estlished to thoroughly hrterize the different res to expnd the potentil of Argentinen orn for domesti nd export uses. This oopertion hs resulted in the doumenttion of the hrdness, mylose, nd strh ontents of numer of these res (Routti et l 2000). Reverse-phse high-pressure liquid hromtogrphy (RP- HPLC) lso ws used to nlyze zein ontent s mens to group nd identify orn res (Routti et l 2000). Most studies investigting the therml properties of strhes from orn hve foused on mutnt orn types suh s wxy (wx), mylose-extender (e), dull (du), or sugry (su) in different kgrounds (Stevens nd Elton 1971; Inouhi et l 1984; Krueger et l 1987; Brokett et l 1988; Snders et l 1990). Our lortory hs onduted extensive investigtions on the therml properties of strh from severl open-pollinted orn popultions nd hs shown signifint vrition mong nd within popultions (White et l 1990). Li et l (1994) hrterized the therml properties of 35 tropil nd semitropil orn popultions nd reported signifint differenes for ll mesured therml properties. The grnule size distriution of the sme 35 orn popultions lso ws exmined, nd signifint differene in the verge grnule size ws reported within nd mong popultions (Cmpell et l 1996). Severl signifint orreltions lso were estlished etween grnule size nd therml properties sed on results from these popultions. The ojetives of this study were to hrterize the therml nd funtionl strh properties of severl orn res from the Argentinen germplsm nd to identify unusul orn res with potentil for further improvement, thus dding to the existing dtse of informtion on the different res of orn. MATERIALS AND METHODS Mterils Severl lndres of orn olleted from different regions in Argentin were stored t the Ative Mize Germplsm Bnk, Pergmino, Argentin (Tle II). All of the smples under study hd een hrterized previously for hrdness, mylose, strh, nd zein ontents (Routti et l 2000,). Severl of the orn res lso were regrown t the Agriulturl Experiment Sttion t Pergmino, TABLE I Desired Strh Chrteristis of Differentil Snning Clorimetry (DSC) Prmeters DSC Prmeter Trget Vlue Onset temperture of geltiniztion (T og ) <61 C Enthlpy of geltiniztion (δ G ) <9.5 J/g or >14.5 J/g Rnge of geltiniztion (R G ) <5.5 C or >14.5 C Enthlpy of retrogrdtion (δ R ) <3.8 J/g Perent retrogrdtion (%R) <20% or >80% Vol. 78, No. 4, 2001 379
Argentin. Corn ws tegorized sed on endosperm type, suh s dent, flint, floury, semident, or semiflint. Corn essions originlly olleted re leled O in this study nd those tht were regrown in Pergmino, Argentin, re leled P. A orn elt inred, Mo-17, grown nd hrvested in Ames, IA, in 1998 ws used s ontrol for omprison. Strh Isoltion Strh for differentil snning lorimetry (DSC) nlysis ws extrted using proedures previously desried y White et l (1990) nd modified y Krieger et l (1997). For the initil sreening of the 35 lndres from the germplsm, strh ws extrted from five rndomly seleted seeds per re. Bsed on the results of the initil sreening, 13 lndres were seleted for further nlyses (Tle II). DSC nlyses of the strh from these 13 lndres were onduted on strh extrted using the single-kernel extrtion proedure from 10 rndomly seleted seeds from eh re. This smpling protool llowed for the determintion of the vriility in strh therml properties within eh re. Lrger quntities of strh, needed to nlyze strh psting properties using Rpid Viso Anlyser (RVA) nd to mesure texturl properties of strh gels, were extrted from 50 g of seed using the proedure desried y Singh et l (1997). DSC Anlysis The therml properties of the strh smples were nlyzed with differentil snning lorimeter equipped with Pyris softwre for Windows pkge (V2.04, Perkin-Elmer, Norwlk, CT) using proedures previously desried (White et l 1990). To mesure the degree of retrogrdtion, the geltinized strh in the DSC pn ws stored for 7 dys t 4 C, the optimum temperture for retrogrdtion, then equilirted t 25 C for 1.5 hr efore eing rerun using DSC from 30 to 120 C t 10 C/min (White et l 1989). All nlyses were onduted in duplite, nd the verge results were reported. Strh geltiniztion properties tht were omputed utomtilly were pek onset temperture (T og ), rnge of geltiniztion (R G ), nd enthlpy of geltiniztion (δ G ). Strh retrogrdtion properties tht were omputed were onset of retrogrdtion (T or ), rnge of retrogrdtion (R R ), nd enthlpy of retrogrdtion (δ R ). Also, pek height index (PHI) ws lulted s the rtio of δ G nd hlf of R G, nd R G or R R ws omputed s twie the differene etween pek temperture nd onset temperture. Psting Properties The psting properties of 13 seleted res were nlyzed y using n RVA model 4 (Newport Sientifi Pty. Ltd., Wrriewood, NSW, Austrli) nd n STD2 temperture profile equipped with Thermoline for Windows softwre (V1.2) (Jennings 1996). Two RVA profiles were otined for eh smple nd results verged. A strh slurry (8% dw) with finl weight of 28 g ws used for eh RVA nlysis. The temperture profile involved heting the slurry for 1 min t 50 C, then heting the slurry to 95 C in 7.5 min. The temperture ws held t 95 C for 5 min, deresed to 50 C in 7.5 Smple Re 380 CEREAL CHEMISTRY TABLE II List of 35 Corn Lndres Used in the Study from the Argentinen Germplsm Yer of Colletion Provine of Colletion Endosperm Type Amylose Strh Reson for Seleting Lndre for Further Anlyses 01-102-P Cristlino Colordo 1989 Buenos Aires Flint 18.9 72.1 03-021-P Cristlino Amrillo Anrnjdo 1988 Entre Rios Flint 18.5 69.7 03-029-P Cmeli 1988 Entre Rios Flint 18.2 65.9 03-032-O Cmeli 1978 Entre Rios Flint 19.1 69.6 O vs. P omprison 03-032-P Cmeli 1988 Entre Rios Flint 18.4 67.0 O vs. P omprison 03-044-O Avtí Morotí Ti 1978 Entre Rios Floury 19.2 71.0 04-035-P Dentdo Amrillo 1989 Corrientes Dent 16.4 62.9 Lowest strh ontent 04-040-P Avtí Morotí Ti 1988 Corrientes Floury 19.0 70.3 04-087-O Complejo Tropil 1978 Corrientes Semiflint 19.5 69.7 05-081-P Dentdo Amrillo 1989 Misiones Dent 16.1 63.0 Lowest mylose ontent 05-087-O Dentdo Amrillo 1977 Misiones Dent 18.8 67.9 07-031-O Cnrio Formos 1977 Formos Semident 23.5 77.8 Highest mylose ontent 07-031-P Cnrio Formos 1988 Formos Semident 20.5 74.5 O vs. P omprison 07-061-P Cnrio Formos 1977 Formos Semident 21.8 76.6 07-061-O Cnrio Formos 1989 Formos Semident 22.0 75.7 07-126-O Cnrio Formos 1977 Formos Semident 23.3 79.0 Highest strh ontent 08-085-O Pisingllo 1977 Slt Flint 18.7 71.1 08-096-O Amrilo de Oho 1977 Slt Floury 17.0 70.7 Lowest mylose to strh rtio 08-173-O2 Cpi Grrpt 1977 Slt Floury 19.2 71.5 Low geltiniztion onset temperture 08-173-O3 Cpi Rosdo 1977 Slt Floury 19.0 72.5 Low geltiniztion onset temperture 10-020-O Pisingllo 1977 Tuum Flint 18.9 69.9 12-080-O Dentdo Blno 1977 Ctmr Dent 18.7 68.8 13-035-P Cristlino Colordo 1989 L Rioj Flint 18.7 67.6 13-049-O Dentdo Blno 1977 L Rioj Dent 19.3 70.3 O vs. P omprison 13-049-P Dentdo Blno 1989 L Rioj Dent 20.4 66.4 Highest mylose to strh rtio 13-064-O Cristlino Amrillo Anrnjdo 1977 L Rioj Flint 19.6 72.0 13-165-O Complejo Tropil 1977 L Rioj Semiflint 20.7 75.0 Low T og nd low δ R 16-007-P Dentdo Blno 1988 Mendoz Dent 18.5 68.1 16-018-O Cristlino Blno 1986 Mendoz Flint 19.1 73.9 16-024-O Cristlino Blno 1986 Mendoz Flint 20.0 72.8 17-026-O Cristlino Colordo 1986 Sn Luis Flint 18.6 69.9 18-026-O Avtí Morotí Ti 1981 L Pmp Floury 19.0 71.6 19-033-O Cristlino Amrillo 1986 Neuquen Flint 19.1 71.7 19-036-86/87 Cristlino Amrillo 1986 Neuquen Flint 19.4 70.1 19-075-O Cristlino Amrillo 1986 Neuquen Flint 19.4 72.3 O = suffix denoting lndres originlly olleted from different regions of Argentin; P = suffix denoting lndres tht were replnted t the Agriulture Experiment Sttion in Pergmino, Argentin. Yer of originl olletion for smples with suffix O; yer of regenertion t Pergmino, Argentin, for smples with suffix P. Amylose nd strh vlues were provided y our ollortors t INTA, Argentin.
min, nd held t 50 C for 2 min. Psting temperture (P onset ), pek visosity (PV), hot pste visosity (HPV), old pste visosity (CPV), rekdown, nd setk were reorded. Gel Strength The strh pstes from the RVA nlysis were nlyzed for gel strength with texture nlyzer (Stle Miro Systems TA.XT2, Texture Tehnologies Corp., Srsdle, NY) equipped with Texture Expert for Windows softwre (V1.11) (Tkhshi nd Sei 1988). After eh RVA run, the geltinized pste ws trnsferred into n luminum ontiner (27 mm dimeter nd depth) nd surrounded on the top y luminum foil to inrese the height y 10 mm. The ontiner ws overed with foil nd stored in nother plsti ontiner with lid to minimize dehydrtion. Gel strength ws tested fter 1 dy t 25 C nd fter 7 dys t 4 C. Smples stored under refrigertion were equilirted to room temperture efore nlysis. Due to limited smple size, texture nlysis dt reported were n verge of five punhes per gel, run only one under eh storge ondition. Texture nlysis ws repeted for few smples for whih there ws enough strh, nd the stndrd devitions were reorded. For gel strength mesurement, the luminum foil ws removed nd the top surfe slied with wire heese utter. The gels were ompressed t speed of 0.9 mm/se to distne of 7.5 mm using stinless steel proe (P/4, 4-mm dimeter). The pek fore t 7.5 mm ws reported s the firmness of the gel for eh storge ondition. Imge Anlysis The single strh smple extrted from 50 g of orn ws mounted on glss mirosope slide nd viewed with Zeiss xiophot mirosope (Zeiss-Kontron, Thornwood, NY) t 50 mgnifition ( 20 y 2.5 Optivr). Strh grnule sizes were otined y following the proedure desried y Jne et l (1992) on 200 individul grnules per eh orn lndre. Sttistil Anlysis Anlysis of vrine (Steel nd Torrie 1980) ws used for dt nlysis. Reltionships etween strh nd mylose ontent, grnule size distriution, DSC, RVA, nd texture prmeters were determined using Person s simple orreltion test (SAS Institute, Cry, NC). Lndre Endosperm Type TABLE III Differentil Snning Clorimetry Vlues from Initil Sreening of 35 Argentinen Corn Lndres T og R G MO-17 (ontrol) Dent 65.0 10.8 13.8 40.2 21.2 6.7 2.60 04-035-P Dent 64.2 12.4 13.3 40.7 19.4 4.5 2.15 05-081-P Dent 62.0 12.5 11.5 40.0 19.8 6.0 1.83 05-087-P Dent 65.9 9.1 11.0 39.4 23.1 5.8 2.41 12-080-O Dent 63.5 10.1 12.4 39.7 22.5 7.2 2.45 13-049-O Dent 64.5 12.1 12.0 39.8 21.9 5.9 1.98 13-049-P Dent 63.2 11.3 12.4 39.7 21.5 6.2 2.20 16-007-P Dent 64.8 11.3 12.9 39.1 23.3 6.1 2.29 01-102-P Flint 62.4 14.2 11.6 40.5 20.0 6.0 1.64 03-021-P Flint 64.8 11.6 12.4 40.6 22.4 6.5 2.14 03-029-P Flint 64.1 11.9 10.8 39.8 21.4 5.2 1.81 03-032-O Flint 65.1 10.6 12.0 40.9 21.4 6.1 2.27 03-032-P Flint 63.3 12.4 12.3 39.5 23.5 6.4 1.98 08-085-O Flint 57.7 13.5 11.6 40.0 19.8 5.8 1.71 10-020-O Flint 52.9 17.9 10.2 40.8 19.4 5.2 1.14 13-035-P Flint 63.1 12.7 12.3 39.2 25.8 5.9 1.93 13-064-O Flint 64.6 10.7 11.9 42.0 19.3 6.1 2.22 16-018-O Flint 60.5 12.9 12.2 40.2 21.3 5.5 1.88 16-024-O Flint 63.2 11.4 12.4 39.5 22.8 7.2 2.17 16-036-O Flint 64.3 10.0 12.3 40.5 20.5 5.5 2.46 17-026-O Flint 63.5 10.9 12.7 40.2 21.6 6.7 2.34 19-033-O Flint 59.3 14.4 12.7 39.6 20.9 5.3 1.76 19-036-O Flint 66.5 8.7 12.1 39.2 22.4 6.0 2.78 19-075-O Flint 63.3 11.1 12.9 40.2 22.1 6.4 2.31 03-044-O Floury 65.2 10.8 12.9 40.5 21.5 6.4 2.39 04-040-P Floury 61.6 11.7 12.1 39.8 20.2 5.8 2.05 08-096-O Floury 57.1 17.1 12.3 40.4 20.0 5.5 1.44 08-173-O2 Floury 58.0 13.0 12.7 39.9 19.8 5.4 1.95 08-173-O3 Floury 58.8 12.8 12.5 40.7 20.0 5.6 1.95 18-026-O Floury 61.4 15.2 12.3 40.4 21.1 6.0 1.62 07-031-O Semident 65.4 10.7 11.9 40.7 21.9 6.4 2.22 07-031-P Semident 62.6 11.4 12.5 39.9 23.4 6.5 2.19 07-061-O Semident 64.1 11.5 11.6 40.4 21.6 5.8 2.02 07-126-O Semident 65.0 9.8 11.8 39.9 22.2 5.9 2.42 04-087-O Semiflint 65.5 10.5 12.5 40.3 20.9 5.4 2.38 13-165-O Semiflint 60.5 13.5 11.9 41.4 19.2 4.6 1.77 Men 62.8 12.0 12.1 40.2 21.4 5.9 2.1 Minimum 52.9 8.7 10.2 39.1 19.2 4.5 1.1 Mximum 66.5 17.9 13.3 42.0 25.8 7.2 2.8 Rnge 13.7 9.2 3.1 2.9 6.6 2.7 1.6 Confidene level (95.0%) 1.0 0.7 0.2 0.2 0.5 0.2 0.1 T og = geltiniztion onset temperture; R G = rnge of geltiniztion temperture; δ G = enthlpy of geltiniztion; T or = retrogrdtion onset temperture; R R = rnge of retrogrdtion temperture; δ R = enthlpy of retrogrdtion; PHI = pek height index (δ G /(0.5 R G )). Vlues re verges of duplite runs from strh extrted from five rndomly seleted seeds. O = suffix denoting lndres originlly olleted from different regions of Argentin; P = suffix denoting lndres tht were replnted t the Agriulture Experiment Sttion in Pergmino, Argentin. δ G (J/g) T or R R δ R (J/g) PHI Vol. 78, No. 4, 2001 381
RESULTS AND DISCUSSION DSC Chrteriztion of Strh Strhes from 35 orn lndres were sreened for therml properties using DSC to identify strhes with therml properties of potentil reserh or ommeril interest. Strhes were onsidered to possess unusul therml properties sed on riteri listed in Tle I, whih drws upon the extensive dtse of therml properties of norml ornstrh from the United Sttes. The lndres of orn sreened inluded different endosperm types suh s dent, flint, floury, semident, nd semiflint nd vried in the levels of strh, mylose, nd protein ontents (Routti et l 2000). These smples re suset of the germplsm ville t the Argentinen Germplsm Bnk. The therml properties of strh from the different lndres exhiited onsiderle vriility (Tle III). Vlue rnges were T og 52.9 66.5 C, R G 8.7 17.9 C, R R 19.2 25.8 C, nd PHI 1.1 2.8 for ll the essions sreened. The T og vlues of the different lndres were skewed y one orn lndre, flint orn (10-020-O) with T og vlue of 52.9 C. This orn is of the Pisingllo re, whih is the type of orn used for poporn. Upon ompring the Fig. 1. Representtive differentil snning olorimetry thermogrms of seleted mize strhes. Mo-17 is Corn Belt inred used s ontrol. therml properties sed on endosperm types, floury orn hd the lowest men vlue for T og (60.8 C) nd the highest for R G (13.5 C). Representtive thermogrms of strhes exhiiting unusul DSC properties re shown in Fig. 1. Erlier studies investigting the therml properties of nonmutnt orn inreds reported T og vlues for strh from flint orn t 62.6 68.1 C, R G vlues t 7.6 13.5 C, nd R R vlues t 16.7 19.2 C (Cmpell et l 1995; Pollk nd White 1997). The sme studies lso reported T og vlues for strh from dent orn t 61.2 71.2 C, R G vlues t 7.8 17.6 C, nd R R vlues t 15.8 19.7 C. Flint orn lndres from the present study showed greter vrition for these properties thn previously reported, wheres the dent orn res exhiited lesser vrition. Li et l (1994) reported the DSC properties of strh from 35 Ltin Amerin orn essions. Although signifint differenes in vrious therml properties were reported in their study, the rnge of therml properties mong the different essions ws smller thn the results otined in this study. Jne et l (1999) reported DSC vlues for vriety of A-type strhes. The T og vlues of these A-type strhes were 56.3 C for rley to 70.3 C for norml rie strh, nd the R G vlues were 6.6 C for rley to 14.4 C for dull-wxy strh from orn. The rnge of DSC ttriutes from the orn lndres in the present study exhiited out the sme degree of vriility s for other A-type strhes, if not higher. Thus, suffiient vriility exists within orn germplsm for rnge of therml properties, mking it possile to rete orn lines with unusul therml properties using the essions from Argentinen germplsm. DSC Properties of Strh from Seleted Lndres of Corn Bsed on the DSC hrteristis suh s low T og or rod R G, nd prmeters suh s low or high strh or mylose ontents, 13 of the 35 orn lndres were seleted for further funtionl nlyses (Tle II). The degree of geneti vriility within eh of the seleted lndres for therml properties ws hrterized y nlyzing strh therml properties on severl single kernels with the DSC. The nlysis ws onduted on strh extrted from 10 rndomly seleted single kernels per re. Anlyzing individul seeds from n er of orn highlights the geneti vriility for therml properties within orn re. The therml properties of the seleted lndres re listed in Tle IV. TABLE IV Differentil Snning Clorimetry (DSC) Vlues of Strh from 13 Seleted Argentinen Corn Lndres Endosperm Type T og R G δ G (J/g) nd Lndre Men Min Mx Rnge Men Min Mx Rnge Men Min Mx Rnge Mo17 (Control) 65.0 10.8 13.8 Overll 64.0 58.2 68.2 10.0 9.7 6.4 17.9 11.5 12.0 8.8 13.8 5.0 Dent 64.3 d 60.0 67.8 7.8 10.2 7.2 17.6 10.4 12.1 9.6 13.8 4.2 04-035-P 65.3 61.5 67.8 6.3 11.6 8.4 17.6 9.2 11.7 11.1 12.4 1.3 05081-P 62.1 60.0 64.4 4.4 11.1 8.4 14.8 6.4 12.1 11.0 12.9 1.9 13-049-O 64.7 60.6 66.9 6.8 9.0 7.2 11.4 4.3 12.4 9.6 13.8 4.2 13-049-P 65.2 63.5 66.9 3.4 8.9 7.2 11.6 4.4 12.2 9.7 13.8 4.1 Flint 65.7 61.5 68.0 6.5 9.5 7.2 14.1 6.8 11.7 8.8 12.9 4.1 03-032-O 66.7 65.9 67.7 1.9 8.5 7.6 9.9 2.3 11.9 10.6 12.9 2.4 03-032-P 64.9 61.5 68.0 6.5 10.4 7.2 14.1 6.8 11.4 8.8 12.4 3.6 Floury 60.8d 58.0 65.2 7.2 8.7 6.9 10.8 3.9 12.3 11.0 13.1 2.1 08-096-O 60.7 59.0 64.3 5.2 8.1 6.9 10.7 3.8 11.8 11.0 12.7 1.7 08-173-O2 61.5 58.2 65.2 7.0 8.7 7.6 9.9 2.3 12.3 11.4 12.9 1.4 08-173-O3 60.2 58.0 63.3 5.3 9.1 7.8 10.8 3.0 12.6 11.4 13.1 1.7 Semident 64.8 58.7 68.2 9.5 10 6.4 17.9 11.5 12.1 9.4 13.7 4.2 07-126-O 65.4 62.9 67.0 4.1 8.7 6.6 10.6 4.0 11.3 9.4 12.1 2.7 07-031-O 66.1 64.8 68.2 3.4 8.1 6.4 9.4 3.0 12.9 12.2 13.7 1.4 07-031-P 62.9 58.7 64.9 6.1 13.3 10.2 17.9 7.6 11.9 10.9 13.3 2.4 Semiflint (13-165-O) 62.3d 59.4 64.0 4.6 9.5 7.6 10.7 3.2 11.6 10.5 12.3 1.8 T og = geltiniztion onset temperture; R G = rnge of geltiniztion temperture; δ G = enthlpy of geltiniztion; T or = retrogrdtion onset temperture; R R = rnge of retrogrdtion temperture; δ R = enthlpy of retrogrdtion. Vlues re verge of duplite runs on DSC of strh extrted from 10 single kernels from eh orn lndre. O = suffix denoting lndres originlly olleted from different regions of Argentin; P = suffix denoting lndres tht were replnted t the Agriulture Experiment Sttion in Pergmino, Argentin. d Vlues followed y the sme letter in the sme olumn re not signifintly different (P < 0.05). 382 CEREAL CHEMISTRY
Strh therml properties from individul kernels within lndre exhiited onsiderle vriility. Strh from severl individul kernels from most lndres exhiited lower T og vlues thn did Mo-17, nd severl of these vlues lso were unusul (<61 C). The men R G vlues of strh from severl lndres were lower thn tht of Mo-17 nd, lthough onsiderle vrition within eh lndre ws oserved for R G vlues, strh from only few kernels exhiited unusul R G vlues (<5.5 or >14.5 C). Dent lndres 04-035-P nd 05-081-P, nd semident lndre 07-031- P, hd individul kernels with R G vlues >14.5 C. The men δ G vlues of strh from ll the lndres were lower thn the δ G vlues of strh from Mo-17, ut only one kernel eh from lndres 13-049-P nd 03-032-P exhiited δ G vlues <9.5 J/g. The men δ R vlues of strhes from most lndres were lower thn the δ R vlue of Mo-17, nd strhes from severl kernels in most lndres exhiited δ R vlues <3.8 J/g. Sttistil nlyses of the dt reveled signifint differenes in the therml properties of strhes when endosperm types were ompred. But the therml properties of strhes etween different lndres were not signifint euse onsiderle vriility ws oserved in the therml properties within eh lndre sed on the dt otined from 10 individul seeds per lndre. This lk of signifine denotes vrition for eh strh therml ttriute within eh lndre of orn. Identifying lndres nd kernels of orn tht re the outliers for different properties ws the ojetive of this sreening proess euse the outliers revel essions possessing trits of potentil use. The high degree of vriility for different therml ttriutes shows the promise for identifying lndres nd kernels within the lndres tht possess new therml properties for use in reeding progrms. Sttistil nlyses lso were onduted to ompre the therml properties etween orn lndres of different endosperm types. Although the nlysis is skewed euse of the uneven, smll smple size within eh endosperm type, signifint differenes were oserved in the therml properties etween the endosperm types for T og, R R, nd δ R (Tle IV). Floury orn strh hd lower men T og, R R, nd δ R thn did strh from ll other orn types. Flint orn hd higher T og nd lower δ R thn did the other endosperm types, exept for floury endosperm orn. Semident orn strh hd the highest vriility in T og nd R G vlues. More speifilly, strhes from one dent lndre, 05-081-P, one semident lndre, 07-031-P, nd the semiflint lndre 13-165-O hd lower men T og vlues thn those of Mo-17 strh. Therml properties lso were ompred etween res tht were originlly olleted (suffix O in the lel) nd then replnted (suffix P ) in the Agriulture Experiment Sttion t Pergmino, Argentin. A omprison of the therml properties of these smples revels tht there ws greter vriility for T og in two of the O smples (03-032-O nd 07-031-O) thn for those tht were regrown (P), wheres re 13-049 hd the opposite trend. The differenes etween the O nd P smples reflet the influene of environment on the therml properties nd highlight the potentil diffiulty in inorporting unusul trits into dpted orn kgrounds. Psting Properties of Strh from Seleted Corn Lndres Signifint differenes were oserved in the psting properties of strh from different lndres of orn (Tle V). Overll, the psting visosities of the strhes from the Argentinen germplsm were greter thn those for norml dent orn (Mo-17). Men P onset temperture for ll the lndres ws 78.7 C, with vlues of 74.9 84.7 C. The men PV vlue for ll the smples ws 158.9 RVU, with vlues of 120.6 172.0 RVU, nd the men HPV vlue for ll the smples ws 92.2 RVU, with vlues of 76.8 101.3 RVU. The men CPV vlue for ll the smples ws 190.8 RVU, with vlues of 150.6 210.0 RVU. The verge rekdown vlue for ll the smples ws 66.7 RVU, nd the vlues were 40.2 77.3 RVU for strhes from different orn lndres. The men setk vlue ws 98.5 RVU, nd the vlues for the different lndres were 73.3 115.3 RVU. The verge slope of the urve from P onset to PV ws 17.6 RVU, nd the vlues were 12.5 25.6 RVU for strhes from the different lndres. When ompring the psting properties of strh from the different endosperm types, only floury endosperm orn ws signifintly different from other endosperm types. Strh from floury orn hd the highest P onset nd the lowest verge PV, CPV, rekdown, nd setk visosities. Floury orn generlly lso rehed the psting visosity erlier thn the other orn types, s mesured y the slope of the urve from P onset to PV. Jne et l (1999) reported psting properties of vriety of A- nd B-type strhes from different otnil soures using the TABLE IV (ontinued) Endosperm Type T og R G δ G (J/g) nd Lndre Men Min Mx Rnge Men Min Mx Rnge Men Min Mx Rnge Mo17 (Control) 40.2 21.2 6.7 Overll 39.9 35.3 43.0 7.7 21.0 15.6 32.3 16.7 5.4 2.7 8.6 6.0 Dent 39.3 35.3 42.6 7.2 21.8 17.2 32.3 15.1 5.7 3.6 8.6 5.1 04-035-P 40.0 39.6 40.6 1.0 19.6 17.2 20.6 3.4 5.3 3.9 5.9 2.0 05081-P 39.6 38.0 40.1 2.1 20.2 19.4 21.2 1.8 5.3 4.6 6.6 2.0 13-049-O 39.2 35.3 42.6 7.2 26.2 19.2 32.3 13.2 7.5 6.1 8.6 2.6 13-049-P 38.6 37.8 39.5 1.7 21.9 20.4 24.4 4.0 5.2 3.6 6.1 2.6 Flint 39 37.2 41.0 3.8 21.5 16.3 25.2 8.9 4.9 3.3 5.8 2.5 03-032-O 39.4 37.4 41.0 3.6 20.3 16.3 23.2 6.9 4.9 3.3 5.8 2.5 03-032-P 38.6 37.2 39.5 2.3 22.6 21.0 25.2 4.2 5.0 4.1 5.6 1.4 Floury 40.9 38.8 42.4 3.6 19.3 15.6 22.0 6.4 5 2.7 6.2 3.6 08-096-O 41.3 40.6 41.8 1.2 19.8 18.4 21.0 2.6 5.7 5.0 6.2 1.2 08-173-O2 40.6 38.8 42.0 3.2 19.3 15.6 22.0 6.4 4.5 2.7 5.3 2.7 08-173-O3 40.8 39.8 42.4 2.6 18.8 16.6 21.4 4.8 5.0 4.1 5.8 1.7 Semident 39.5 37.9 41.9 4.0 20.9 15.8 25.6 9.8 5.4 3.8 6.9 3.1 07-126-O 40.2 39.1 41.8 2.7 20.0 18.8 21.8 3.0 5.1 3.8 6.9 3.1 07-031-O 38.7 37.9 39.9 2.0 22.2 20.2 25.6 5.4 5.4 5.1 6.2 1.1 07-031-P 39.7 38.6 41.9 3.3 20.4 15.8 22.4 6.6 5.5 4.8 6.3 1.5 Semiflint (13-165-O) 42.2 41.7 43.0 1.3 19.7 18.0 21.0 3.0 6 5.4 6.7 1.2 Vol. 78, No. 4, 2001 383
RVA. The P onset vlues of these strhes were 63.5 C for potto to 91.2 C for rley. The PV vlues were 58 RVU for rley to 250 RVU for green nn, with high of 702 RVU for potto. Setk vlues were 6 RVU for wxy mrnth strh to 202 RVU for mung en strh. The psting properties of strhes from the different lndres of orn in the present study lso exhiited onsiderle vriility. The vriility in the psting properties of orn strh in the present study lso ws signifintly higher thn the vriility reported y Ymin et l (1999) hrterizing the psting properties of strhes from mutgenized orn. Texturl Properties of Strh Gels from Seleted Corn Res Signifint differenes were oserved in the texturl properties of the strh gels mong the different orn lndres (Tle VI). The verge fore required to rek the gel fter 1 dy ws 16.8 g, with vlues for the different lndres t 12.8 21.3 g. The verge fore required to rek the gel fter 7 dys of storge t refrigertion temperture ws 24.0 g, with vlues for the lndres t 16.7 35.0 g. Strhes from lndres of the floury type orn generlly required the lest mount of fore to rek the gel mong ll strh types fter oth 1 nd 7 dys. Ymin et l (1999) reported texture vlues for strh gels otined from mutgenized orn tht were lower for gels stored for 1 nd 7 dys thn reported in the present study. But the vriility indued in gel strength y mutgenized orn ws lower thn the nturl vriility reported in this study mong the vrious lndres from the germplsm. Strh Grnule Size Distriution The grnule size distriutions of strh from the different orn lndres nd endosperm types re listed in Tle VII. The dt for eh lndre were then divided into two size rnges, <10-µm nd >10-µm dimeter, nd reported s perentge of the totl numer of grnules mesured. Vriility in strh grnule size distriution is, therefore, mesure of the skewness in the distriution of grnule sizes within eh lndre of orn. The verge dimeter of the strh grnules ross ll lndres nd endosperm types ws 8.96 µm, with rnge of 17.56 µm. Floury endosperm orn lndres hd greter men strh grnule size thn did strh from ll other endosperm types. Floury orn 08-096-O nd dent orn 13-049-O hd strh with most grnules >10 µm in dimeter nd dent orn 13-049-P hd strh with most grnules <10 µm. TABLE VI Texturl Properties of 13 Seleted Argentinen Corn Lndres Endosperm Type nd Lndre 1 Dy Fore (g) 7 Dy Fore (g) Control (Mo-17) 13.1 20.3 Overll (n = 13) 16.8 24.0 Dent 17.3x 24.7x 04-035-P 17.7 d d 25.4 d 05-081-P 14.7ef 21.1 e 13-049-O 17.7 d 28.4 13-049-P 19.2 26.7 Flint 16.4xy 24.4x 03-032-O 15.3d f 23 d 03-032-P 17.7 d 25.4 Floury 13.3y 18.3y 08-096-O 12.8f 16.7f 08-173-O2 13.5f 19.5d f 08-173-O3 13.6f 18.2ef Semident 19.1x 28.1x 07-126-O 19.3 26.5 07-031-O 21.3 35.0 07-031-P 16.1 e 23.3 e Semiflint 18.8x 25.9x 13-165-O 18.8 25.9 Minimum 12.8 16.7 Mximum 21.3 35.0 Rnge 8.5 18.3 Vlues re the verges of five mesurements from gel smple. O = suffix denoting lndres originlly olleted from different regions of Argentin; P = suffix denoting lndres tht were replnted t the Agriulture Experiment Sttion in Pergmino, Argentin. Different letters (x,y) within the sme olumn indite signifint differenes t P < 0.05 etween endosperm types. d Different letters ( f) within the sme olumn indite signifint differenes t P < 0.05 etween different lndres. Endosperm Type nd Lndre P onset 384 CEREAL CHEMISTRY TABLE V Psting Properties of 13 Seleted Argentinen Corn Lndres HPV PV CPV Brekdown Setk Slope (RVU/se) Control (Mo-17) 76.7 84.5 136.6 183.8 52.1 99.3 11.9 Overll (n = 13) 78.7 92.2 158.9 190.8 66.7 98.5 17.6 Dent 77.7x d 95.6x 166.2x 198.1x 70.6x 102.6x 17.7xy 04-035-P 77.6 f e 101.3 163.0 205.6 61.7ef 104.3 d 14.2gh 05-081-P 80.1 82.7 d 159.9 170.5d 77.3 87.8de 21.2 13-049-O 75.9d f 97.3 172.0 206.5 74.8 109.3 18.0 e 13-049-P 77.4 f 101.0 169.8 210.0 68.8 e 109.0 17.4 f Flint 77.9x 90.4xy 165.5x 200.7x 75.1x 110.3x 16.3z 03-032-O 78.9 d 91.9 165.5 197.3 73.5 d 105.3 16.6d f 03-032-P 76.9 f 88.8 d 165.5 204.2 76.6 115.3 15.9e g Floury 83.3y 81.9y 135.8y 162.5y 53.9y 80.6y 20.5x 08-096-O 84.7 88.6 d 151.5 183.3 62.9ef 94.6d 25.6 08-173-O2 83.5 80.4d 120.6 153.7d 40.2g 73.3e 18.5d 08-173-O3 81.6 76.8d 135.3 150.6d 58.5f 73.8e 17.6 e Semident 76.0x 96.7x 165.0x 200.4x 68.3x 103.7x 15.5z 07-126-O 75.4ef 100.1 165.5 202.8 65.5 f 102.7 d 14.9f h 07-031-O 74.9f 93.6 158.3 190.4 64.6d f 96.7 d 12.5h 07-031-P 77.7 f 96.3 171.2 208.0 74.9 111.7 19.2 Semiflint 78.2x 100.0x 167.5x 197.2x 67.5xy 97.2xy 16.7yz 13-165-O 78.2 e 100.0 167.5 197.2 67.5 f 97.2 d 16.7d f Minimum 74.9 76.8 120.6 150.6 40.2 73.3 12.5 Mximum 84.7 101.3 172.0 210.0 77.3 115.3 25.6 Rnge 9.6 24.5 51.4 59.4 37.1 42.0 13.1 P onset = psting onset temperture; HPV = hot pste visosity; PV = psting visosity; CPV = finl visosity; Slope = slope from P onset to PV temp. Vlues re verge of duplite runs. O = suffix denoting lndres originlly olleted from different regions of Argentin; P = suffix denoting lndres tht were replnted t the Agriulture Experiment Sttion in Pergmino, Argentin. d Different letters (x z) within the sme olumn indite signifint differenes t P < 0.05 etween endosperm types. e Different letters ( h) within the sme olumn indite signifint differenes t P < 0.05 etween different lndres.
Cmpell et l (1996) reported men strh grnule dimeters t 16.2 18.2 µm for strhes from 35 orn popultions from the Ltin Amerin germplsm. Strh grnule dimeters in the present study from the different orn lndres were signifintly lower thn dt reported y Cmpell et l (1996). Cmpell et l (1996) did not, however, report the distriution of strh grnule size for the different orn popultions. Correltion of Dt Although orreltion dt do not signify uslity, orreltion nlyses of the physil nd ompositionl ttriutes of the strhes with the therml nd psting properties of strhes potentilly provide vlule insights into the mehnisms ontriuting to the funtionl properties of the strhes. The orreltion dt with levels of signifine P < 0.05 or greter re listed in Tle VIII. Strh ontent orrelted positively with mylose ontent, ut did not orrelte with ny funtionl property. The mylose ontent of the strh, however, orrelted signifintly with severl funtionl ttriutes. Amylose ontent did not signifintly orrelte with DSC prmeters. Sski et l (2000), investigting the therml nd psting properties of wxy nd nonwxy whet, reported negtive orreltion etween the geltiniztion endpoint temperture nd δ G with mylose ontent. In this study, we did not oserve reltionship etween mylose ontent nd geltiniztion properties mesured using DSC, proly euse the rnge of mylose ontent of orn in this study ws low (18 22%) ompred with the study reported y Sski et l (2000), in whih mylose ontent ws 0.8 20%. Amylose ontent exhiited positive orreltion with the RVA mesurement of HPV nd negtive orreltion with the P onset nd the slope of the urve from psting onset to the pek psting temperture. Sski et l (2000) reported negtive orreltion etween mylose ontent nd psting visosity mesured using n RVA. Although this study showed no reltionship etween mylose ontent nd psting visosity, it did show tht strh with lower mylose ontent hieved pek visosity t fster rte, s mesured y the slope of the urve from psting onset to pek visosity. Amylose ontent further orrelted positively with gel texture fter oth 1 nd 7 dys of storge. This result is in greement with tht reported y Gines et l (2000), who investigted the vrious physiohemil ttriutes of whet ultivrs. Strh grnule size orrelted only with the onset temperture mesured using DSC nd with P onset, HPV, nd slope mesured using the RVA. Lrger verge grnule size resulted in lower geltiniztion nd psting onset tempertures nd higher HPV. Grnule size orrelted strongly with strh texturl properties with lrger grnule size resulting in firmer gel texture t oth 1 nd 7 dys. Severl signifint reltionships lso were oserved etween strh therml properties mesured using DSC nd the funtionl properties mesured using the RVA. Strhes with lower T og hd higher P onset, hieved PV erlier, nd hd lower PV, rekdown, nd setk vlues. CONCLUSIONS Germplsm nks re vlule resoures for identifying nturl vriility of different plnt nd seed trits. Sreening the essions in germplsm nk ids in the identifition of plnts with unusul properties rnging from gronomi trits to funtionl nd ompositionl trits of the seeds. Results from this study onfirm the presene of wide vrition in the therml nd funtionl properties of strh from severl lndres of orn in the Argentinen germplsm. Therml properties of strh mesured using DSC identified severl orn lndres with unusul properties. The therml properties of some of the orn reported in this study re omprle to the therml properties of strh from severl other rop speies. Furthermore, severl of these orn res exhiited unusul properties in severl kernels tht were nlyzed, inditing ertin degree of geneti homogeneity for tht trit. These orn res show promise for further regenertion to rete inred lines with unusul trits. The psting nd texturl properties of strh gels otined from strh from different orn res lso exhiited onsiderle vriility omprle with those properties reported for strh from other rop speies. Thus, the potentil for further improvement of orn res exists not only sed on therml properties, ut diretly for speifi funtionl ttriutes s well. The orreltion nlyses suggest tht the vriility in therml nd funtionl ttriutes is funtion of mylose ontent nd strh grnule size. The strong orreltion oserved etween the therml properties nlyzed using DSC nd the funtionl properties mesured using n RVA nd texture nlyzer will llow for Endosperm Type nd Lndre Men (µm) TABLE VII Strh Grnule Size Distriution of 13 Seleted Argentinen Corn Lndres Minimum (µm) Mximum (µm) Control (Mo-17) 8.60 2.28 19.22 16.94 71.0 29.0 Overll (n = 13) 8.96 1.88 19.44 17.56 63.3 36.7 Dent 8.68 1.96 19.28 17.32 68.0 32.0 04-035-P 8.32 2.60 19.20 16.60 71.6 28.4 05-081-P 8.66 3.42 16.74 13.34 69.2 30.8 13-049-O 9.88 1.96 19.28 17.32 54.2 45.8 13-049-P 7.86 3.20 15.38 12.18 77.1 22.9 Flint 9.38 2.26 18.86 16.60 60.9 39.6 03-032-O 9.10 2.26 18.44 16.18 63.7 36.3 03-032-P 9.66 2.60 18.86 16.26 58.2 41.8 Floury 9.64 2.10 18.94 16.84 57.9 42.1 08-096-O 9.92 2.98 18.52 15.56 54.7 45.3 08-173-O2 9.38 2.10 18.94 16.84 63.2 36.8 08-173-O3 9.66 2.50 18.70 16.20 55.7 44.3 Semident 8.58 1.88 19.54 17.56 66.8 33.2 07-126-O 8.44 1.88 16.18 14.30 66.2 33.8 07-031-O 7.98 3.16 17.68 14.32 75.1 24.9 07-031-P 9.32 2.94 19.44 16.50 59.2 40.8 Semiflint (13-165-O) 8.80 2.38 18.36 15.98 62.7 37.3 Vlues re verges of dimeters of 200 strh grnules. O = suffix denoting lndres originlly olleted from different regions of Argentin; P = suffix denoting lndres tht were replnted t the Agriulture Experiment Sttion in Pergmino, Argentin. Different letters within the sme olumn indite signifint differenes t P < 0.05 etween endosperm types. Rnge (µm) <10 µm (%) >10 µm (%) Vol. 78, No. 4, 2001 385
TABLE VIII Correltion Coeffiients for 13 Argentinen Corn Lndres Grnule Psting Properties Texturl Properties Vrile Amylose Size (men) P onset HPV PV CPV BD SB Slope 1 Dy Fore 7 Dy Fore Strh 0.82* Therml properties T OG 0.43**** 0.77* 0.61* 0.52*** 0.62* 0.55** 0.71* 0.68* 0.69* R G δ G T OR 0.51*** 0.71* 0.64* 0.64* 0.64* 0.39**** 0.47**** R R 0.52*** δ R 0.40**** 0.60* 0.50*** Psting properties P onset 0.59** 0.47*** HPV 0.40**** PV CPV BD SB Slope 0.53*** 0.44**** Texture properties 1 dy fore 0.70* 0.50*** 0.86* 0.69* 0.58** 0.64* 0.53** 0.74* 7 dy fore 0.70* 0.40*** 0.87* 0.55** 0.52*** 0.54** 0.47**** 0.71* *, **, ***, **** = P < 0.001, 0.005, 0.01, nd 0.05, respetively. P onset = psting onset temperture; HPV = hot pste visosity; PV = psting visosity; CPV = finl visosity; BD = rekdown (PV HPV); SB = setk (CPV PV); slope = slope from P onset to PVtemp; T og = geltiniztion onset temperture; R G = rnge of geltiniztion temperture; δ G = enthlpy of geltiniztion; T or = retrogrdtion onset temperture; R R = rnge of retrogrdtion temperture; δ R = enthlpy of retrogrdtion. extrpoltion of strh properties using the smller smple sizes llowed for DSC nlyses. Further ollortive studies re underwy to develop inred lines using these exoti res of orn to rete lines with unusul strh properties nd improved gronomi trits. LITERATURE CITED Brokett, E., Thompson, D., Dvis, T., nd Boyer, C. 1988. Geltiniztion hrteristis of strh from du, wx, e, nd e wx endosperm of sweet orn inred I 5125. Strh 40:175-177. Cmpell, M. R., Pollk, L. M., nd White, P. J. 1995. Geneti vrition for strh therml nd funtionl properties mong nonmutnt mize inreds. Cerel Chem. 72:281-286. Cmpell, M. R., Li, J., Berke, J. T., nd Glover, D. V. 1996. Vrition in strh grnule size in tropil mize germplsm. Cerel Chem. 73:536-538. Gines, C. S., Reker, M. O., Tilley, M., Finney, P. L., Wilson, J. D., Behtel, D. B., Mrtin, R. J., Sei, P. A., Lookhrt, G. L., nd Donelson, T. 2000. Assoitions of strh gel hrdness, grnule size, wxy lleli expression, therml psting, milling qulity, nd kernel texture of 12 soft whet ultivrs. Cerel Chem. 77:163-168. Goodmn, M. M. 1985. Exoti mize germplsm: Sttus, prospets nd remedies. Iow Stte J. Res. 59:497-527. Inouhi, N., Glover, D. V., Sugimoto, Y., nd Fuw, H. 1984. Development hnges in strh properties of severl endosperm mutnts of mize. Strh 36:8-12. Jne, J., Shen, L., Chen, J., Lim, S., Ksemsuwn, T., nd Nip, W. K. 1992. Physil nd hemil studies of tro strhes nd flours. Cerel Chem. 69:528-535. Jne, J. L., Chen, Y. Y., Lee, L. F., MPherson, A. E., Wong, K. S., Rdosvljevi, M., nd Ksemsuwn, T. 1999. Effets of mylopetin rnh hin length nd mylose ontent on the geltiniztion nd psting properties of strh. Cerel Chem. 76:629-637. Jennings, S. D. 1996. The effet of orn mturity on the quntity nd qulity of orn strh produed y wet milling. MS thesis. Deprtment of Food Siene nd Humn Nutrition: Iow Stte University, Ames, IA. Krieger, K. M., Duvik, S. A., Pollk, L. M., nd White, P. J. 1997. Therml properties of orn strh extrted with different lending methods: Mirolender nd homogenizer. Cerel Chem. 75:553-555. Krueger, B. R., Knutson, C. A., Inglett, G. E., nd Wlker, C. E. 1987. A differentil snning lorimetry study on the effet of nneling on geltiniztion ehvior of orn strh. J. Food Si. 52:715-718. Li, J., Berke, T. G., nd Glover, D. V. 1994. Vrition for therml properties of strh in tropil mize germplsm. Cerel Chem. 71:87-90. Pollk, L. M., nd White, P. J. 1997. Therml strh properties in orn elt nd exoti orn inred lines nd their rosses. Cerel Chem. 74:412-416. Routti, J. L., Borrs, F. S., Ferrer, M. E., nd Beitz, J. A. 2000. Grouping nd identifition of Argentine mize res y prinipl omponent nlysis of zein reverse-phse HPLC dt. Cerel Chem. 77:91-95. Routti, J. L., Borrs, F. S., Ferrer, M. E., Perildi, M., nd Knutson, C. A. 2000. Evlution of qulity ftors in Argentine mize res. Cerel Chem. 77:24-26. Snders, E. B., Thompson, D. B, nd Boyer, C. D. 1990. Therml ehvior during geltiniztion nd mylopetin fine struture for seleted mize genotypes s expressed in four inred lines. Cerel Chem. 67:594-602. Sski, T., Ysui, T., nd Mtsuki, J. 2000. Effet of mylose ontent on geltiniztion, retrogrdtion, nd psting properties of strhes from wxy nd nonwxy whet nd their F1 seeds. Cerel Chem. 77:58-63. Singh, S. K., Johnson, L. A., Pollk, L. M., Fox, S. R., nd Biley, T. B. 1997. Comprison of lortory nd pilot-plnt orn wet-milling proedures. Cerel Chem. 74:40-48. Steel, G. D., nd Torrie, J. H. 1980. Proedures of Sttistis: A Biometril Approh, 2nd ed. MGrw-Hill: New York. Stevens, D. J., nd Elton, J. H. 1971. Therml properties of strh/wter system. I. Mesurement of het of geltiniztion y differentil snning lorimetry. Strh/Sterke 23:8-11. Tkhshi, S., nd Sei, P. A. 1988. Pste nd gel properties of prime orn nd whet strhes with nd without ntive lipids. Cerel Chem. 65:474-483. White, P. J., As, I. R., nd Johnson, L. A. 1989. Freeze-thw stility nd refrigerted-storge retrogrdtion of strhes. Strh 41:176-180. White, P. J., As, I., Pollk, L., nd Johnson, L. A. 1990. Intr- nd Interpopultion vriility of therml properties of mize strh. Cerel Chem. 67:70-73. Ymin, F. F., Lee, M., Pollk, L. M., nd White, P. J. 1999. Therml properties of strh in orn vrints isolted fter hemil mutgenesis of inred line B73. Cerel Chem. 76:175-181. [Reeived Septemer 5, 2000. Aepted Ferury 19, 2001.] 386 CEREAL CHEMISTRY