Beef Cttle Reserh 2008 PACKAGING ATMOSPHERES ALTER BEEF TENDERNESS, FRESH COLOR STABILITY, AND INTERNAL COOKED COLOR 1 J. P. Groel, M. E. Dikemn, M. C. Hunt, nd G. A. Milliken 2 Introdution Severl met qulity trits ffet onsumers overll purhse deisions nd stisftion with met produts, ut olor is the mjor ftor ffeting purhsing deisions. Aording to some reserhers, tenderness is the most importnt pltility ttriute in onsumers overll eting experiene. Cse-redy pkging in the met industry is growing t rpid rte nd generlly inludes modified tmosphere pkging (MAP) with speifi gses. Advntges of MAP inlude use of entrlized lotion, improved snittion ontrol, more onsistent produts, nd inresed mrketing flexiility. Pkging eef in highoxygen (HiO 2 ) MAP results in desirle right red len olor ut n hve detrimentl effets on other qulity trits, inluding inresed off-flvors nd deresed tenderness. Use of ron monoxide (CO) hs een pproved y USDA nd the Food nd Drug Administrtion for use t levels up to 0.4% in retil MAP. Produts in MAP tht inlude CO hve improved eef olor stility nd extended disply time. Premture rowning, originlly disovered in ground eef, results when met is ooked to tempertures lower thn wht is neessry to kill hrmful pthogens ut ppers well done internlly. This phenomenon is lso found in whole musle steks nd n e ttriuted to pkging environments, inluding HiO 2 MAP. Therefore, ojetives of our study were to evlute the effets of different gs ompositions in different MAP systems vs. vuum pkging on grin finished eef tenderness, disply olor stility, nd internl ooked olor. Experimentl Proedures Strip loins (n=14 pirs) from USDA Selet, A-mturity rsses were ssigned to either 14 dy tenderness mesurement or to disply nd then 18 or 28 dy tenderness mesurement. Loins were frited on dy 7 postmortem into 1-inh-thik steks. Seven steks from the nterior end of the strip loin were ut nd ssigned to one of six pkging tretments or to initil tenderness mesurement. Steks 8-10 were ut posterior to the first seven steks, ut in hlf nd ssigned to pkging tretment, nd used for internl ooked olor determintion. One full stek ws used for initil tenderness. Pkging tretments were: vuum pkging (VP); 80% O 2 /20% CO 2 (HiO 2 ); 0.4% CO/35% CO 2 /64.6%N 2 (ULO 2 CO); 0.4% CO/99.6% CO 2 (ULO 2 COCO 2 ); 0.4% CO/99.6% N 2 (ULO 2 CON 2 ); or 0.4% CO/99.6% Ar (ULO 2 COAr). Steks pkged in HiO 2 MAP were held in drk storge t 35.6 F for 4 dys, 1 This projet ws funded y The Beef Chekoff nd the Knss Beef Counil. The uthors express ppreition to Crgill Met Solutions, Wihit, KS, for the use of their filities nd equipment. 2 Deprtment of Sttistis. 14
nd ll other steks were held in the drk t 35.6 F for 14 dys. Steks were then displyed under fluoresent lighting for 7 dys with instrumentl olor mesured on dy 0 nd 7 of disply. Ten trined olor pnelists ssigned olor sores. Instrumentl tenderness ws mesured using Wrner-Brtzler sher fore (WBSF). Steks for WBSF nd ooked olor were ooked to 158 F. Results nd Disussion There ws pkging tretment dy intertion (P<0.01) for WBSF (Figure 1). Wrner-Brtzler sher fore vlues from strip loin steks indite tht, s system, HiO 2 MAP t dy 18 postmortem resulted in steks eing less tender thn those pkged in ULO 2 with CO MAP or VP t dy 28 postmortem. On dy 14 postmortem, WBSF ws similr (P>0.05), nd ll tretments were more tender (P<0.01) on dy 14 postmortem thn on dy 7 postmortem. Conversely, steks pkged in HiO 2 MAP were less tender (P<0.05) thn other tretments t the end of disply, likely due to 10 dys less ging time (18 vs. 28 dys postmortem) resulting from shorter drk storge period (4 dys) for HiO 2 MAP thn for ULO 2 CO MAP nd VP tretments (14 dys). Steks pkged in ll pkging tretments used for 14 dys postmortem WBSF were held for 7 dys in the drk nd then ooked for WBSF mesurement. Drk storge times for HiO 2 nd ULO 2 tmospheres were designed to replite industry prtie. There ws pkging tretment dy intertion (P<0.001) for disply visul olor (Figure 2). Disply olor sores indited tht steks from ll tretments eme drker (P<0.05) s dy of disply inresed, s ws expeted. Steks pkged in HiO 2 MAP were slightly righter (P<0.05) ording to disply olor sores thn steks pkged in ULO 2 COAr or ULO 2 CO MAP on dy 0 of disply. Vuum-pkged steks hd the most onsistent disply olor throughout the 7 dys of disply nd hnged only from right 15 purplish red or pink to dull purplish red or pink during the entire disply period. Steks in VP were expeted to e stle in olor nd not hnge muh throughout the 7 dys of disply; however, mny onsumers find the purplish red olor of VP met undesirle regrdless of the onsistent disply olor. Steks pkged in HiO 2 MAP were n undesirle reddish tn y dy 7 of disply, wheres steks pkged in the ULO 2 CO MAP tretments were either dull red or slightly drk red y dy 7 of disply. There ws pkging tretment dy intertion (P<0.001) for disolortion sores (Figure 3). Steks pkged in VP or the four ULO 2 MAP lends with CO hd little or no surfe disolortion over the 7 dys of disply. Steks pkged in HiO 2 MAP disolored fster (P<0.05) nd to greter extent (P<0.05) thn those pkged in ny of the ULO 2 MAP or VP tretments. Steks pkged in HiO 2 MAP disolored (P<0.05) y dy 4 of disply nd hd 56% more (P<0.05) metmyogloin disolortion thn steks pkged in ny other pkging tretment. Inluding O 2 in the pkge llowed for oxidtion of myogloin nd thus resulted in reddish tn olor y dy 7 of disply. Exluding O 2 from the pkge, s with VP or ULO 2 CO MAP tretments, llows myogloin to remin in more stle form (red) longer nd delys the onset of metmyogloin (tn/rown) olor formed through oxidtion of myogloin. There ws pkging tretment min effet (P<0.001) for internl ooked olor s ssessed y * vlue nd sturtion index (Figure 4). Steks pkged in HiO 2 hd the lowest (P<0.05) * vlues (rownest) for internl ooked olor of ll pkging tretments. Steks pkged in ULO 2 COCO 2 nd in VP hd intermedite * vlues, nd those pkged in ULO 2 COAr, ULO 2 CO, nd ULO 2 CON 2 hd the highest (P<0.05) * vlues (reddest). Premture rowning is defined y internl ooked olor of met tht is rown t tempertures where it should still pper red
in olor nd is relted to the oxidtive stte of met prior to ooking. Results indited tht steks pkged in ULO 2 COAr, ULO 2 CO, nd ULO 2 CON 2 MAP hd redder (P<0.05) internl ooked olor thn steks pkged in VP. Steks were ooked to medium degree of doneness (158 F), whih should result in pinkish internl olor. Steks pkged in HiO 2 MAP were rown inside t this temperture. This ould pose definite sfety risk, espeilly if onsumers ook intt steks to n internl olor nd do not use met thermometer to determine sfe endpoint ook temperture. In onlusion, results from this study indited tht steks pkged in HiO 2 MAP hve less disply olor stility thn ll other pkging tretments evluted euse they disolor fster nd to greter extent. Ultr-low oxygen + CO MAP nd VP steks hd etter fresh olor stility nd equl or etter tenderness thn steks pkged in HiO 2 MAP. Pkging tmospheres ltered internl ooked olor, with steks pkged in HiO 2 MAP exhiiting premture rowning. Strip loin steks pkged in the HiO 2 MAP system were less tender t the end of disply thn other pkging tretments, perhps due to the shorter ging time ssoited with the HiO 2 MAP system. Implitions Pkging eef in ULO 2 CO MAP provides right red olor with extended disply olor stility, llows for longer ging time nd inresed tenderness, nd results in n internl ooked olor tht is expeted for medium degree of doneness, ll of whih would re enefiil to the met industry. 13 WBSF (l) 11 9 7 7 14 18/28 Dys Postmortem Figure 1. Pkging Tretment Dy Wrner-Brtzler Sher Fore Mens for Strip Loin Steks Pkged in Different Atmospheres. Mens without ommon supersript letter differ (P<0.05). VP = vuum pkging; HiO 2 = 80%/O 2, 20%CO 2 ; ULO 2 CO = 64% N 2, 35% CO 2, 0.4% CO; CO 2 = 16
Disply Color Sore 5 4.5 4 3.5 3 2.5 0 1 2 3 4 5 6 7 Dy of disply VP HiO2 ULO2CO CO2 N2 A Figure 2. Disply Color Sore Mens for Strip Loin Steks Pkged in Different Atmospheres. VP = vuum pkging; HiO 2 = 80%/O 2, 20%CO 2 ; ULO 2 CO = 64% N 2, 35% CO 2, 0.4% CO; CO 2 = Color sore sle: 2 = right red or pinkish red; 5 = reddish tn or pinkish tn. Disolortion Sore 3 2 1 0 1 2 3 4 5 6 7 Dy of disply d e Figure 3. Disply Disolortion Sore Mens for Strip Loin Steks Pkged in Different Atmospheres. Mens without ommon supersript letter differ (P<0.05). VP = vuum pkging; HiO 2 = 80%/O 2, 20%CO 2 ; ULO 2 CO = 64% N 2, 35% CO 2, 0.4% CO; CO 2 = Disolortion sore: 1= 0%, 2=1-19%, 3=20-39% metmyogloin. 17
35 30 25 20 15 10 5 0 * Sturtion index Figure 4. Instrumentl Internl Cooked Color Mens for Strip Loin Steks Pkged in Different Atmospheres. Mens without ommon supersript letter differ (P<0.05). VP = vuum pkging; HiO 2 = 80%/O 2, 20%CO 2 ; ULO 2 CO = 64% N 2, 35% CO 2, 0.4% CO; CO 2 = 18