Effects of Ascorbic Acid and Antioxidants on the Color of Irradiated Ground Beef K.C. NAM AND D.U. AHN

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1 JFS: Food Chemistry nd Toxiology Effets of Asori Aid nd Antioxidnts on the Color of Irrdited Ground Beef K.C. NAM AND D.U. AHN Food Chemistry nd Toxiology ABSTRACT: Irrdition signifintly deresed the redness of ground eef (P < 0.05), nd the visile olor of eef hnged from right red to green/rown, depending on the ge of met. Addition of sori id (0.1%, wt/ wt) in ground eef prior to irrdition prevented olor hnges in irrdited eef, nd the effet of sori id eme greter s the ge of met or storge time fter irrdition inresed. Ground eef with dded sori id hd signifintly lower oxidtion-redution potentil thn the ontrol (P < 0.05), nd the low oxidtionredution potentil of met helped mintin the heme pigments in redued form. Sesmol + -toopherol hd no effet in stilizing olor of irrdited eef. Keywords: irrdition, sori id, olor, oxidtion-redution potentil, ground eef Introdution COLOR IS A PRIME QUALITY PARAMETER DETERMINING CONSUMER eptne of met. Consumers wnt to hve the olor of their met within norml rnge (Seidemn nd others 1984), nd disolored mets re onsidered inferior or old. Liu nd others (1995) indited tht the loss of vlue due to disolortion in eef t the retil level in the U.S. ould e over 700 million dollrs per yer. Irrdition is the most effetive tehnology for ontrolling pthogeni miroorgnisms in ground eef, ut it n influene the olor of eef signifintly. The olor hnges indued y irrdition re different, depending on niml speies, musle type, irrdition dose, nd pkging type (Stterlee nd others 1971; Luhsinger nd others 1996; Ahn nd others 1998). In generl, light met suh s pork loin nd poultry rest met developed pink olor, wheres drk met suh s eef eme rown or gry fter irrdition (Millr nd others 1995; Nnke nd others 1998; Ahn nd others 1998; Kim nd others 2002). Numerilly lulted totl olor differene ( E) showed tht the olor hnges y irrdition were greter in eef thn in turkey or pork (Kim nd others 2002), nd the olor of irrdited eef ws unttrtive for onsumers. Ground eef omprises over 40% of eef onsumption in the U.S. (AMI 1998); nd it is the most suseptile form of met to miroil ontmintion during proessing nd hndling. Therefore, prevention of pthogens from ground eef is the most demnding. However, irrdition is not widely used y the eef industry due to dverse olor formtion in irrdited eef. Food ntioxidnts re used in fresh nd further proessed met to prevent oxidtive rnidity nd improve olor stility. Some phenoli ntioxidnts suh s vitmin E hve free-rdil-svenging properties nd stop free-rdil retions in met during storge (Gry nd others 1996; Morrissey nd others 1998). Therefore, ddition of phenoli ntioxidnts to met is effetive in deresing oxidtive retions either y svenging free rdils produed y irrdition or y terminting free rdil retions (Nm nd Ahn 2003). Asori id is reduing gent, whih inhiits myogloin oxidtion nd rown olor development in unirrdited eef (Wheeler nd others 1996; Lee nd others 1999; Snhez-Eslnte nd others 2001). Our preliminry studies indited tht irrdited eef imprted different olors rnging from rown to greenish-rown depending on the ge of the met. Although mintining ttrtive olor in irrdited ground eef is very importnt, little work hs een done to improve the olor of irrdited eef. The ojetive of this study ws to determine the effet of sori id nd seleted ntioxidnts on the olor of eef with different postmortem ging times efore irrdition nd storge times fter irrdition. Currently, FDA-USDA regultions llow no dditives dded to met efore irrdition. However, dditives n e used in met to minimize qulity hnges in irrdited met when new petition is pproved. Mterils nd Methods Smple preprtion Beef loins (Longissimus dorsi) with 3 different ging times fter slughter were used in this study. The freshest loins were otined from 4 nimls 2 d fter slughter in the Met Lortory, Iow Stte Univ. (Ames, Iow, U.S.A.). The other loins were purhsed from 4 lol groery stores on 2 seprte osions: 1 lot of the loins ws purhsed 1 d efore smple preprtion; the other lot ws purhsed 2 wk efore smple preprtion nd further ged t. Therefore, when the lipid oxidtion of 3 types of eef loins were determined t 0 d using TBARS method (Ahn nd others 2000), they were 0.17, 0.31, nd 0.81 mg mlondildehyde/kg met, respetively, depending on their ging time (Figure 1). For onveniene, the 3 loins were nmed short-term-ged, ged, nd long-termged, respetively. One loin tken from eh of 4 seprte nimls or met loks purhsed from eh of 4 groery stores were treted s replition. Eh met lok ws ground seprtely through 3-mm plte. Five different tretments were prepred: (1) nonirrdited ontrol, (2) irrdited ontrol, (3) with 0.1% (wt/wt) L-sori id (Fisher Sientifi, Fir Lwn, N.J., U.S.A.) dded nd irrdited, (4) with 0.01% sesmol (3,4-methylenedioxyphenol; Sigm, St Louis, Mo., U.S.A.) % -toopherol (Aldrih Chemil Co., Milwukee, Wis., U.S.A.) dded nd irrdited, nd (5) with 0.1% sori id % sesmol % -toopherol dded nd irrdited. The omintion of sesmol + -toopherol ws seleted on the sis of our previous studies with pork nd turkey mets (Nm nd Ahn 2003; Lee nd Ahn 2003) JOURNAL OF FOOD SCIENCE Vol. 68, Nr. 5, Institute of Food Tehnologists Further reprodution prohiited without permission

2 Asori id ffets irrdited eef olor... Eh dditive ws dded to the ground eef (1 kg) nd then mixed for 1 min in owl mixer (Model KSM 90; Kithen Aid In., St. Joseph, Mih., U.S.A.). The mixed met smples were ground gin through 3-mm plte to ensure even distriution of the dded dditives. Asori id nd sesmol were dissolved in wrm (65 C) distilled wter (eh 5%, wt/vol) nd -toopherol ws diluted in minerl oil (25%, wt/vol) efore use. All tretments were dded with the sme mounts of wter nd minerl oil to provide the sme moisture nd oil onditions. Ptties were prepred with ground eef (pproximtely 50 g) nd individully pkged in oxygenpermele gs (polyethylene, 4 in 6 in, 2 mil, ml O 2 /m 2 / dy t 2; Asso. Bg Co., Milwukee, Wis., U.S.A.), stored t overnight, nd irrdited the next morning. The smples were stored t overnight efore irrdition. Ionizing rdition The eroilly pkged ground eef ws irrdited t 2.5 kgy using Liner Aelertor Fility (Cire IIIR; Thomson CSF Lin, St. Auin, Frne) with 10 MeV energy nd 10.2-kW power level. The verge dose rte ws 83.5 kgy/min. Alnine dosimeters were pled on the top nd ottom surfes of smple nd were red using 104 Eletron Prmgneti Resonne spetrometer (Bruker Instruments In., Billeri, Mss., U.S.A.) to hek the sored dose. The dose rnge sored t met smples ws to kgy (mx/min rtio ws 1.11). The nonirrdited ontrol (0 kgy) smples were exposed to 22 C wheres other smples were irrdited. After irrdition, the irrdited nd nonirrdited met smples were immeditely returned to old room nd stored for 7 dys. Color nd ORP vlues of the smples were determined on 1, 4, nd 7 d of storge. Color mesurement CIE olor vlues were mesured on the surfe of met smples using LSn olorimeter (Hunter Asso. Ls In., Reston, V., U.S.A.) using n illuminnt A with m perture. The olorimeter ws lirted ginst lk nd white referene tile overed with the sme pkging g used for smples. The olor L* (lightness), * (redness), nd * (yellowness) vlues were otined (AMSA 1991). An verge vlue from 2 rndom lotions on eh smple surfe ws used for sttistil nlysis. The hue ngle vlues were lulted from tn 1 (*/*). Oxidtion-redution potentil (ORP) To redue the devition of ORP vlues depending on the lotion of met ptty, modified method using met homogente ws used. Met smple (5 g), 15 ml deionized distilled wter, nd Figure 1 Initil TBARS vlues of ground eef with different ging times Tle 1 CIE olor L* vlues of irrdited ground eef treted with different dditives during eroi storge t Irrdited Storge Control Control Asori 2 S + E 3 A + S + E 4 SEM Short-term-ged (0.17 * ) Dy y 40.4 y 39.2 y Dy y 41.2 y 40.3 y Dy x 44.0 x 41.7 x SEM Dy y 43.1 y Dy x 43.6 xy Dy x 44.9 x SEM Long-term-ged (0.81 * ) Dy z 48.2 y 48.2 y 48.0 y 46.6 y 0.4 Dy x 52.4 x 50.9 x 49.9 x 48.3 x 0.5 Dy y 53.0 x 50.4 x 50.0 x 49.3 x 0.4 SEM * Initil TBARS vlue of met (mg MDA/kg met) 1 Nonirrdited 2 Asori id 0.1% 3 Sesmol 0.01% + -toopherol 0.01% 4 Asori id 0.1% + sesmol 0.01% + -toopherol 0.01% Vlues with different letters within row re signifintly different (P < 0.05). x z Vlues with different letters within olumn of the sme smple re signifintly different (P < 0.05). 50 L utylted hydroxytoluene (7.2% in ethnol) were pled in 50-mL test tue nd were homogenized using Brinkmn Polytron (Type PT 10/35; Brinkmn Instrument In., Westury, N.Y., U.S.A.) for 15 s t high speed. The ORP vlues of homogentes were determined using ph/ion meter (Aumet 25; Fisher Sientifi, Fir Lwn, N.J., U.S.A.) equipped with pltinum eletrode filled with n eletrolyte solution (4 M KCl sturted with AgCl). Sttistil nlysis The experiment ws ftoril design (3 [ging] 5 [tretment] 3 [storge]) with 4-replition. Dt were nlyzed using the generlized liner model proedure of SAS softwre (SAS Inst. 1995). Student-Newmn-Keul s multiple rnge test ws used to determine signifint differenes etween the men vlues of tretments. Men vlues nd stndrd error of the mens (SEM) were reported. Signifine ws defined t P < Results nd Disussion Color vlues The CIE olor L*, *, nd * vlues of irrdited ground eef during eroi storge indited tht olor L* vlue inresed s the ging time of eef inresed (Tle 1). During storge fter irrdition, L* vlues of ground eef lso showed n inresing trend s the storge time inresed, nd the inrese in L* vlue ws more pprent in met from long-term-ged eef thn the other ones. Compred with nonirrdited ontrols, irrdition did not influene the L* vlues of eef from ll stges of ging. Addition of sori id nd/or sesmol + -toopherol hd either little or inonsistent effet on the L* vlues of irrdited ground eef. Irrdition redued the redness (* vlue) of ground eef signifintly ut with vrying degree depending on ging time (Tle 2). Immeditely fter irrdition, the olor of ground eef hnged from right red to greenish rown, whih would e n unttrtive eef olor for onsumers. The olor of irrdited eef ws totlly different from tht of irrdited pork or poultry rest, whih ws pink or red. Food Chemistry nd Toxiology JFS is ville in serhle form t Vol. 68, Nr. 5, 2003 JOURNAL OF FOOD SCIENCE 1687

3 Asori id ffets irrdited eef olor... Food Chemistry nd Toxiology Tle 2 CIE olor * vlues of irrdited ground eef treted with different dditives during eroi storge t Irrdited Storge Control Control Asori 2 S + E 3 A + S + E 4 SEM Short-term-ged (0.17 * ) Dy x 17.4 x 21.3 y 17.4 y Dy y 17.0 ex 24.5 x 18.6 dx Dy y 14.8 ey 25.6 x 16.6 dy SEM Dy x 17.3 x 22.7 y Dy x 16.9 dx 25.9 x Dy dy 15.3 dy 26.1 x SEM Long-term-ged (0.81 * ) Dy x 17.6 x 19.0 y 14.7 y 17.2 y 0.3 Dy ey 12.5 dy 23.0 x 15.7 xy 19.7 x 0.3 Dy ey 11.9 dy 23.2 x 16.2 x 20.0 x 0.3 SEM * Initil TBARS vlue of met (mg MDA/kg met). 1 Nonirrdited 2 Asori id 0.1% 3 Sesmol 0.01% + -toopherol 0.01% 4 Asori id 0.1% + sesmol 0.01% + -toopherol 0.01% e Vlues with different letters within row re signifintly different (P < 0.05). x z Vlues with different letters within olumn of the sme smple re signifintly different (P < 0.05) Tle 3 CIE olor * vlues of irrdited ground eef treted with different dditives during eroi storge t Irrdited Storge Control Control Asori 2 S + E 3 A + S + E 4 SEM Short-term-ged (0.17 * ) Dy x y 20.4 y 21.3 y 0.4 Dy xy x 22.0 x 23.1 x 0.4 Dy y 20.0 d 24.6 x 20.6 dy 23.3 x 0.4 SEM Dy x y Dy xy x Dy y x SEM Long-term-ged (0.81 * ) Dy x 22.1 x 21.4 z 19.7 y 20.4 y 0.3 Dy dz 21.1 y 23.3 y 20.1 dy 21.3 y 0.4 Dy y 22.7 x 25.1 x 21.5 x 23.3 x 0.4 SEM * Initil TBARS vlue of met (mg MDA/kg met) 1 Nonirrdited 2 Asori id 0.1% 3 Sesmol 0.01% + -toopherol 0.01% 4 Asori id 0.1% + sesmol 0.01% + -toopherol 0.01% d Vlues with different letters within row re signifintly different (P < 0.05). x z Vlues with different letters within olumn of the sme smple re signifintly different (P < 0.05). Tle 4 Hue ngles (degree) of irrdited ground eef treted with different dditives during eroi storge t Irrdited Storge Control Control Asori 2 S + E 3 A + S + E 4 SEM Short-term-ged (0.17 * ) Dy y 49.8 y 45.4 x 49.6 y Dy x 51.0 y 44.0 ey 49.7 y 45.9 d 0.3 Dy xy 53.5 x 43.9 dy 51.1 x SEM Dy y 50.6 z xy 0.4 Dy y 52.2 y y 0.4 Dy x 53.5 x 43.4 d x 0.6 SEM Long-term-ged (0.81 * ) Dy z 51.5 z 48.4 dx x 0.3 Dy y 59.2 y 45.3 ez dy 0.4 Dy x 62.3 x 47.2 ey dx 0.4 SEM *Initil TBARS vlue of met (mg MDA/kg met) 1 Nonirrdited 2 Asori id 0.1%. 3Sesmol 0.01% + -toopherol 0.01%. 4 Asori id 0.1% + sesmol 0.01% + -toopherol 0.01%. e Vlues with different letters within row re signifintly different (P < 0.05). x zvlues with different letters within olumn of the sme smple re signifintly different (P < 0.05). Nm nd Ahn (2002) reported tht the omplex of heme pigments with ron monoxide produed y irrdition ws responsile for the inresed redness in irrdited turkey rest. The formtion of CO-heme omplex, however, ould not explin the olor hnges in eef fter irrdition euse, wheres the prodution of ron monoxide in eef y irrdition ws similr to those of light mets (Kim nd others 2002), the pigment ontent in eef ws muh higher (> 10-fold) thn tht in light mets. Therefore, the ontriution of CO-heme pigment to the olor of ground eef ws muh smller thn tht of light mets. Giroux nd others (2001) speulted tht free inding sites of myogloin n ret with free rdils suh s hydroxy or sulfuryl rdils produed y irrdition nd form metmyogloin nd sulfmyogloin responsile for rown nd green olor, respetively. However, little informtion on the pigments responsile for the off-olor in irrdited eef is ville. Asori id inorported into eef t the level of 0.1% (wt/wt) ws very effetive in mintining redness (* vlue) of irrdited ground eef for 7 d storge t. On the other hnd, sesmol + toopherol hd no effet in preventing olor hnges, nd did not show ny synergisti effet etween sori id nd sesmol + toopherol in ground eef y irrdition. The degree of ging ws ritil ftor on the redness of eef during storge, regrdless of irrdition. The * vlues of shortterm-ged eef were not hnged muh during storge, nd the redness ws higher in nonirrdited thn irrdited eef. Longterm-ged eef, however, showed drsti dereses in * vlues during storge, nd nonirrdited ground eef hd lower * vlues thn irrdited eef. Therefore, in long-term-ged ground eef, the olor of irrdited met looked etter thn tht of nonirrdited met during storge. This differene in olor etween fresh nd old mets ould e relted to the loss of reduing power in old met (long-term-ged). Asori id inresed the * vlues of irrdited ground eef nd the olor stilizing effet of sori id ws more distint in long-term-ged thn in short-term-ged irrdited ground eef. Only the ground eef with dded sori id produed higher * vlues thn the met with sori id + sesmol + -toopherol. Thus, the use of sori id ws more effetive in stilizing irrdited eef olor thn using it with other ntioxidnts. However, ddition of strong ntioxidnts long with sori id would e more enefiil in ontrolling lipid oxidtion in irrdited ground eef during storge. Sesmol nd -toopherol will e effetive in retrding utoxidtion of eef lipids. At the eginning of storge, the * vlues of ground eef de JOURNAL OF FOOD SCIENCE Vol. 68, Nr. 5, 2003 JFS is ville in serhle form t

4 Asori id ffets irrdited eef olor... resed y irrdition (Tle 3); this result is onsistent with tht of Kim nd others (2002). Asori id hd tendeny to inrese * vlues of irrdited eef during storge, ut its effet on * vlues ws not s ritil s on * vlues. The hue ngle ws reported to e more preise mesure of olor thn Hunter * vlue (Moissev nd Cornforth 1999). Ground eef with long ging time hd higher hue ngle vlues (P < 0.05) thn shorter ones (P < 0.05), inditing tht ged met hd lower redness nd higher yellowness thn short-term-ged eef (Tle 4). Irrdition inresed the hue ngle vlues of short-term-ged Short-term ged Aged Long-term ged Figure 2 Oxidtion-redution potentil of irrdited ground eef treted with different dditives during eroi storge t., nonirrdited ontrol;, irrdited ontrol; irrdited sori id dded; irrdited sesmol + -toopherol dded; irrdited sori id + sesmol + -toopherol dded. to e: Different letters within storge time indite tht the mens re signifintly different (P < 0.05). d e d nd ged ground eef ut deresed those of long-term-ged eef. Lrger hue ngle vlues were ssoited with less redness of eef ptties (Vn Lk nd others 1996). The ddition of sori id lowered signifintly the hue ngle vlues of irrdited eef (P < 0.05), nd the effet eme stronger with inresing storge time. The higher * vlues ssoited with sori idtreted ground eef resulted in lower hue ngle vlues for these smples. Oxidtion-redution potentil Beuse the red olor intensity of ferrous heme pigment is stronger thn tht of ferri heme pigment, oxidtion-redution potentil of met is very importnt ftor for olor hnges. The ddition of sori id with or without sesmol + -toopherol signifintly lowered the ORP vlues of irrdited ground eef regrdless of the ge of met (Figure 2). However, the ORP vlues of irrdited ground eef with sesmol + -toopherol were not muh different from tht of the ontrol, inditing tht the derese of ORP in irrdited ground eef ws used y sori id. The lowered ORP vlues y sori id mintined heme pigments in the ferrous stte nd stilized the olor of irrdited ground eef. Asori id elerted metmyogloin redution y donting eletrons to the ferri stte of heme (Judge nd others 1989) nd filitted the onversion of ferrimyogloin to ferrous myogloin (Anderson nd Skisted 1992). With inresed storge time fter irrdition, ORP vlues of ground eef inresed stedily in ll tretments, ut ground eef with sori id dded still mintined lower vlues thn others over the storge time. Although the hemil form of heme pigment in irrdited eef hs not een lerly identified, the hnged olor y irrdition ould e reverted to the desirle red olor y the reduing ility of sori id. Conlusions BECAUSE COLOR CHANGES IN IRRADIATED BEEF WERE UNIQUELY DIStinguishle (from right red to green/rown), it would e very diffiult to implement irrdition tehnology in the eef industry without ontrolling disolortion prolems. As in nonirrdited eef, ddition of sori id t 0.1% (wt/wt) to ground eef prior to irrdition stilized the olor of ground eef during eroi storge. The olor stilizing effet of sori id ws derived from the reduing power of sori id, whih mintined the heme pigments in eef in redued form. However, detiled informtion on the olor ompounds in irrdited eef is not understood yet. Referenes Ahn DU, Olson DG, Jo C, Chen X, Wu C, Lee JI Effet of musle type, pkging, nd irrdition on lipid oxidtion, voltile prodution, nd olor in rw pork ptties. Met Si 47(1): Ahn DU, Jo C, Du M, Olson DG, Nm KC Qulity hrteristis of pork ptties irrdited nd stored in different pkging nd storge onditions. Met Si 56(2): [AMSA] Amerin Met Siene Assn Guidelines for met olor evlution. In: Proeedings of the 44th reiprol met onferene. Chigo, Ill.: Ntl. Live Stok nd Met Bord. p [AMI] Amerin Met Inst Met nd poultry fts. Wshington, DC: Amerin Met Inst. Andersen HJ, Skisted LH Kinetis nd mehnism of therml oxidtion nd photooxidtion of nitrosylmyogloin in queous solution. J Agri Food Chem 40(10): Giroux M, Outtr B, Yefsh R, Smorgiewiz W, Suier L, Lroix M Comined effet of sori id nd gmm irrdition on miroil nd sensoril hrteristis of eef ptties during refrigerted storge. J Agri Food Chem 49(2): Gry JI, Gom EA, Bukley DJ Oxidtive qulity nd shelf life of mets. Met Si 43(S): Judge MD, Aerle ED, Forrest JC, Hendrik HB, Merkel RA Properties of fresh met. In: Priniples of met siene. Duuque, Iow: Kendll/Hunt Pulishing Co. p Kim YH, Nm KC, Ahn DU Color, oxidtion-redution potentil, nd gs prodution of irrdited met from different niml speies. J Food Si Food Chemistry nd Toxiology JFS is ville in serhle form t Vol. 68, Nr. 5, 2003 JOURNAL OF FOOD SCIENCE 1689

5 Asori id ffets irrdited eef olor... Food Chemistry nd Toxiology 67(5): Lee EJ, Ahn DU Effet of ntioxidnts on the prodution of off-odor voltiles nd lipid oxidtion in irrdited turkey rest met nd met homogentes. J Food Si (Forthoming). Lee BJ, Hendriks DG, Cornforth DP A omprison of rnosine nd sori id on olor nd lipid stility in ground eef ptties model system. Met Si 51(3): Liu Q, Lnri MC, Shefer DM A review of dietry vitmin E supplementtion for improvement of eef qulity. J Anim Si 73(10): Luhsinger SE, Kropf DH, Gri-Zeped CM, Hunt MC, Mrsden JL, Ruio-Cns EJ, Kstner CL, Kueker WG, Mt T Color nd oxidtive rnidity of gmm nd eletron em irrdited oneless pork hops. J Food Si 61(5):1000 5, Millr SJ, Moss BW, MDougll DB, Stevenson MH The effet of ionizing rdition on the CIE L olor o-ordintes of hiken rest met s mesured y different instruments. Int J Food Si Tehnol 30(6): Moiseev IV, Cornforth DP Tretments for prevention of persistent pinking in drk-utting eef ptties. J Food Si 64(4): Morrissey PA, Sheehy PJA, Glvin K, Kerry JP, Bukley DJ Lipid stility in met nd met produts. Met Si 49(S): Nm KC, Ahn DU Cron monoxide-heme pigment is responsile for the pink olor of irrdited rw turkey rest met. Met Si 60(1): Nm KC, Ahn DU Use of ntioxidnts to redue lipid oxidtion nd offodor voltiles of irrdited pork homogentes nd ptties. Met Si 63(1):1 8. Nnke KE, Sernek JG, Olson DG Color hrteristis of irrdited vuum-pkged pork, eef, nd turkey. J Food Si 63(6): Snhez-Eslnte A, Djenne D, Torresno G, Beltrn JA, Ronles P The effets of sori id, turine, rnosine nd rosemry powder on olor nd lipid stility of eef ptties pkged in modified tmosphere. Met Si 58(4): SAS Inst SAS users guide. Cry, NC: SAS Inst., In. Stterlee LD, Wilhelm MS, Brnhrt HM Low dose gmm irrdition of ovine metmyogloin. J Food Si 36(3): Seidemn SC, Cross HR, Smith GC, Durlnd PR Ftors ssoited with fresh met olor: review. J Food Qul 6(3): Vn Lk RLJM, Berry BW, Solomon MB Vritions in internl olor of ooked eef ptties. J Food Si 61(2): Wheeler TL, Koohmrie M, Shkelford SD Effet of vitmin C onentrtion nd o-injetion with lium hloride on eef retil disply olor. J Anim Si 74(8): MS Sumitted 2/26/03, Revised 3/31/03, Aepted 4/21/03, Reeived 4/21/03 Authors re with the Animl Siene Dept., Iow Stte Univ., Ames, Iow Diret inquiries to uthor Ahn (E-mil: duhn@istte.edu) 1690 JOURNAL OF FOOD SCIENCE Vol. 68, Nr. 5, 2003 JFS is ville in serhle form t