Met nd Food Sfety Needle-Free Injection Enhncement of Beef Strip Loins with Phosphte nd Slt Hs Potentil to Improve Yield, Tenderness, nd Juiciness ut Hrm Texture nd Flvor B.A. Crow, M.E. Dikemn, L.C. Hollis, R.A. Pheus, A.N. Ry, T.A. Houser, nd J.P. Groel Introduction Met is the most importnt pltility ttriute ffecting consumers overll eting experience. Injection enhncement nd lde tenderiztion hve long een used to improve this importnt trit. Injection enhncement hs een shown to improve, juiciness, color stility, nd cooking yield, ut not ll solutions hve een dequtely evluted. Thus, there is need to conduct reserch on the effectiveness of common enhncement solutions. We pulished results from n extensive study compring solution of phosphte, slt, nd rosemry with solution of clcium lctte nd rosemry injected y using trditionl needle injection. There were no differences in Wrner-Brtzler sher force vlues etween tretments, ut trined pnelists scored steks enhnced with clcium lctte nd rosemry to e less tender nd juicy thn steks enhnced with phosphte, slt, nd rosemry. However, steks enhnced with the phosphte solution hd higher incidence of metllic nd slty off-flvors, drker initil color, nd more color deteriortion. Becuse needle-free injection enhncement is reltively similr to trditionl needle-injection enhncement with regrd to food sfety, it should e evluted for its effects on met color, instrumentl, sensory trits, nd yields. Ojectives of this reserch were to determine the effects of injection method (needlefree vs. needle injection) nd solution (clcium lctte vs. phosphte solution) on met color, instrumentl, sensory trits, pump yield, nd cooking loss of eef Longissimus lumorum muscles. Experimentl Procedures Experiment Beef Longissimus muscles (n = 5) from USDA Select, A-mturity crcsses were otined from commercil ttoir t 2 dys postmortem nd stored t 4 F until 9 dys postmortem. Ft ws trimmed to 0.3 in., nd ech loin ws hlved nd then ssigned rndomly to one of two injection tretments: needle or needle-free. A Plexigls templte with holes spced 0.38 in. prt ws used to spce the injection sites for needle-free injection. In the needle-free tretment, the dorsl nd ventrl sides of the strip loins were injected t 25 psi. Needles on the needle injector were spced 0.70.0 in. prt. The injector ws set to chieve desired pump yield of 2% y injecting from the ft side only. A solution contining 2.2% slt, 4.4% sodium tri-polyphosphte, This reserch ws funded in prt y eef nd vel producers nd importers through their $-per-hed checkoff nd ws produced for the Cttlemen s Beef Bord nd stte eef councils y the Ntionl Cttlemen s Beef Assocition. 24
Met nd Food Sfety nd.5% potssium lctte ws used for injection. After injection, ech muscle section ws llowed to drin for 30 minutes efore finl weight ws tken. After injection, four steks (.0-in. thick) were cut from the nterior end of ech muscle section. Two of these steks were plced on seprte Styrofom trys, covered with polyvinyl chloride film, nd plced into simulted retil disply for visul color evlution. The remining two steks were vcuum pckged; one ws stored t 4 F for 4 dys until it ws used for Longissimus slice sher force mesurement, nd the other ws frozen for sensory nlysis. Steks used for visul color evlution were displyed under continuous fluorescent lighting for 5 dys t 4 F. Trined visul color pnelists (n = 8) evluted initil color on dy 0 of disply nd disply color nd surfce discolortion on dys to 5 of disply. On dy 3 postmortem, sher force steks were cooked in forced-ir convection oven set t 325 F to n internl temperture of 58 F nd llowed to cool for 2 minutes t room temperture efore 0.4-in.-thick, 2.0-in.-long slice ws removed from the lterl end of ech stek prllel to the muscle fiers nd shered perpendiculr to the muscle with n Instron Universl Testing Mchine. Eight trined pnelists evluted steks. Steks were thwed overnight, cooked to 58 F, sliced into.0 0.5 0.5 in. smples, nd served wrm to pnelists. Pnelists lso recorded verl descriptors for norml texture, such s slick, ruery, or mushy. Experiment 2 For ech of two replictions on 2 seprte dys, 5 eef Longissimus muscles from strip loins from USDA Select, A-mturity crcsses were otined t 2 dys postmortem nd stored t 4 F until 5 dys postmortem. Ft ws trimmed to 0.3 in., nd ech strip loin ws hlved. Then, the hlves were ssigned rndomly to one of four tretments: needle injected with the sme clcium lctte solution used in experiment, (2) needle-free injected with the sme clcium lctte solution, (3) needle injected with the sme phosphte solution used in experiment, or (4) needle-free injected with the sme phosphte solution. Injection enhncement, slice sher force, nd sensory pnel evlution conducted s in experiment. Disply color nd discolortion dt were nlyzed s split-plot design using the mixed model procedure (PROC MIXED) of SAS (SAS Institute, Inc., Cry, NC). Sensory, cooking loss, pump yield, nd slice sher force dt were nlyzed using nlysis of vrince (ANOVA) in the PROC MIXED procedure in SAS. Results nd Discussion Experiment There ws considerle vrition in pump yield for oth injection methods; however, there ws trend (P=0.08) towrd higher pump yields for the needle-free tretment. Tretment hd no effect (P>0.05) on initil color scores t dy 0. However, needleinjected steks were drker on dy of disply ut not fter dy. As expected, discolortion scores indicted tht steks from oth tretments hd incresing mounts of discolortion s dy of disply incresed (P<0.000); the gretest increse occurred fter dy 3. 25
Met nd Food Sfety Slice sher force vlues showed tht ll steks were tender, ut steks from loins injected using the needle-free technology (7.0 l) were more tender (P<0.05) thn those from loins injected with the trditionl needle injector (22.27 l). The trend (P=0.08) towrd higher pump yields for the needle-free tretment could hve plyed role in the greter of the needle-free steks. Loins injected with the needle-free device hd lower cooking loss percentges (P<0.05) thn loins injected with the needle injector, perhps ecuse there ws trend (P=0.08) towrd higher pump yields with the needle-free tretment. It is logicl tht ny increse in distriution of the enhncement solution throughout the met tht hppened with needle-free injection could hve reduced cooking losses. Myofirillr, juiciness, connective tissue mount, nd overll were not different (P>0.05) etween tretments. Steks from the needle-free tretment hd less (P<0.05) eef flvor thn steks from the needle tretment (3.6 vs. 4.9; Figure ). Pnelists lso reported greter (P<0.05) off-flvor scores in the needlefree tretment (3.9) thn in the needle tretment (5.). The most common off-flvors were slty, sopy, livery, nd metllic. These off-flvor descriptors were reported firly evenly for oth tretments; the primry difference ws tht of the off-flvors ws greter for the needle-free tretment. The sopy descriptor ws used lmost exclusively for steks in the needle-free tretment. The slty off-flvor ws the most common descriptor, nd lmost every smple in oth tretments received tht descriptor. A few comments from pnelists indicted tht steks in the needle-free tretment hd slick, mushy texture. Experiment 2 The needle-free loins injected with the phosphte solution hd higher (P<0.05) pump yields thn loins in ll other tretment comintions. There ws no difference (P>0.05) etween needle nd needle-free tretments when the clcium lctte solution ws used. Neither needle nor needle-free loins injected with the clcium lctte solution hd pump yields tht differed from those of the needle-injected loins injected with the phosphte solution. Steks injected with the phosphte solution hd lower (P<0.05) slice sher force vlues thn steks injected with the clcium lctte solution, ut there were no differences (P>0.05) in slice sher force etween needle nd needle-free tretments, which contrdicts results from experiment. There ws no difference (P>0.05) in cooking loss etween needle nd needle-free injection for loins injected with clcium lctte; however, loins injected with clcium lctte hd higher (Figure 2, P<0.05) cooking loss thn loins injected with the phosphte solution. Pnelists did not detect differences (P>0.05) etween needle nd needle-free tretments for myofirillr, juiciness, eef flvor, connective tissue mount, nd overll. However, the needle-injected steks hd fewer (P<0.05) offflvors. Slty ws the most common off-flvor, nd it ws fr more common to loins injected with the phosphte solution, which contined 2.2% slt. Texture scores were higher (P<0.05) for needle-injected steks, mening tht pnelists perceived the texture of needle-injected steks to e closer to tht of norml, nonenhnced steks. The most common descriptors for norml texture were mely, geltin, crunchy, slick, or mushy. 26
Met nd Food Sfety The geltin descriptor ws more common mong steks enhnced with the phosphte solution, wheres steks enhnced with the clcium lctte solution more commonly received mely texture descriptor. Myofirillr, juiciness, connective tissue mount, nd overll were scored lower (P<0.05) for loins enhnced with the clcium lctte solution thn for loins enhnced with the phosphte solution (Figure 3). Steks enhnced with clcium lctte hd lower (P<0.05) incidence of off-flvors nd more norml texture. Implictions Literture compring needle-free injection enhncement with trditionl needle injection enhncement ws, until now, not ville. Enhncement with needle-free vs. needle injection did not hve detrimentl effect on met color nd resulted in reduced cooking loss. However, needle-free injection resulted in more off-flvor, with the sopy descriptor eing exclusive to the needle-free tretment. Anorml textures descried s slick or mushy were lso ssocited with needle-free steks. Enhncement with the phosphte solution resulted in greter myofirillr nd overll, juiciness, nd cooking yield with less connective tissue ut lso cused more norml texture, descried s geltin, nd more off-flvor, with common descriptors of slty or livery. Additionl reserch needs to e conducted to develop prototype needle-free injector with multiple injection tips to llow more direct comprison of needle nd needle-free injection with or without enhncement solutions. Sensory pnel score 8 7 6 5 4 3 Needle Needle-free 2 Myofirillr Juiciness Beef flvor Connective tissue mount Overll Off flvor Texture Sensory trits Mens within sesory trit with different letters differ (P<0.05). Figure. Trined sensory pnel scores for Longissimus lumorum steks injected with needle or needle-free method (experiment ). Myofirillr nd overll scle: = extremely tough, 4 = slightly tough, 8 = extremely tender; Juiciness scle: = extremely dry, 4 = slightly dry, 8 = extremely juicy; Beef flvor scle: = extremely lnd, 4 = slightly lnd, 8 = undnt; Connective tissue mount scle: = undnt, 4 = moderte, 8 = none; Off-flvor scle: = undnt, 4 = moderte, 8 = none; Texture scle: = extremely norml, 4 = slightly norml, 8 = extremely norml. 27
Met nd Food Sfety 30% c c Needle 25% Needle-free Cooking loss 20% 5% 0% 5% 0 Clcium lctte Phosphte Solution Mens with different letters differ (P<0.05). Figure 2. Cooking loss for Longissimus lumorum steks injected with clcium lctte or phosphte solution with needle or needle-free method (experiment ). 8 7 Clcium lctte Phosphte Sensory pnel score 6 5 4 3 2 Myofirillr Juiciness Beef flvor Connective tissue mount Overll Off flvor Texture Sensory trits Mens within sesory trit with different letters differ (P<0.05). Figure 3. Trined sensory pnel scores for Longissimus lumorum steks injection enhnced with clcium lctte or phosphte solution (experiment 2). Myofirillr nd overll scle: = extremely tough, 4 = slightly tough, 8 = extremely tender; Juiciness scle: = extremely dry, 4 = slightly dry, 8 = extremely juicy; Beef flvor scle: = extremely lnd, 4 = slightly lnd, 8 = undnt; Connective tissue mount scle: = undnt, 4 = moderte, 8 = none; Off-flvor scle: = undnt, 4 = moderte, 8 = none; Texture scle: = extremely norml, 4 = slightly norml, 8 = extremely norml. 28