Faculty Mentor

Duane Wulf


Research was conducted in two phases: first to determine optimal pump percentage for each of five pH-enhanced beef muscles and then to determine the effect of pH enhancement on consumer acceptability of beef steaks. Phase I was a 5 x 4 factorial design with five muscles: longissimus lumborum (LL), gluteus medius (GM), triceps brachii (TB), biceps femoris (BF), and psoas major (PM) and four pump percentages: 0, 10, 20, and 30% to determine optimum pump percentage for each muscle using an 8- member trained sensory panel. Phase II was a 5 x 2 factorial design with the same five muscles and two treatments: control (CON) and pH-enhanced (PHE) to quantify desirability using a 182-member central-location consumer panel. Muscles designated for pH enhancement were injected with a solution containing water, ammonium hydroxide, and salt (technology patented by Freezing Machines, Inc.). All muscles were stored in vacuum packages, cut into 2.5-cm-thick steaks, and cooked to 7I°C on electric clam-shell grills for the trained panel and gas grills for the consumer panel. Purge loss and pH were measured on raw muscles. Cooking loss, calculated moisture retained after cooking, and Wamer-Bratlzer shear force (WBS) were measured on cooked steaks. In Phase I, pH increased, purge loss increased, calculated moisture retained after cooking increased, and WBS decreased for all muscles as pump percentage increased from 0 to 30% (P < 0.05), except that WBS of BF was not affected by pump percentage (P = 0.55). Juiciness and tenderness of LL increased as pump percentage increased from 0 to 30% (P < 0.05), but 30% pump resulted in a slightly non-meat texture and slight off-flavors (P < 0.05). Juiciness, tenderness, and beef flavor intensity of GM was greatest at 20% pump compared to other pump percentages (P < 0.05). Juiciness and tenderness of TB was greater at 30% pump than at other pump percentages (P < 0.05), but 30% pump also caused more non-meat textures in TB than other pump percentages (P < 0.05). Juiciness of BF was greater at 30% pump than at other pump percentages (P < 0.05), and tenderness of BF was greater at 20 and 30% pump compared to 0 and 10% pump (P < 0.05). Tenderness of PM increased as pump percentage increased from 10 to 30% (P < 0.05). Based on Phase I results, we determined optimum pump percentages were 15% for LL, 20% for GM, 10% for TB, 30% for BF, and 15% for PM, which were used for PHE in Phase 11. Consumer ratings for 'overall like' were higher for PHE than CON for LL (7.70 vs. 6.64), GM (7.40 vs. 6.10), and BF (5.09 vs. 4.14) (P < 0.05). For LL, GM, and BF, consumers rated PHE higher than CON for like of tenderness/texture'. like of juiciness', and like of flavor' (P < 0.05). For PHEvs. CON,respectively, percentage of consumers responding 'yes' to "Would you be satisfied with this steak if you had eaten it in a restaurant?" was 80 vs. 65% for LL (P < 0.05), 74 vs. 47% for GM (P < 0.05), 59 vs. 49% for TB (P < 0.05), 31 vs. 20% for BF (P < 0.05), and 73 vs. 81% for PM (P = 0.10). In conclusion, different muscles had different optimum pump percentages for pH enhancement,and pH enhancement improved consumer acceptability in some muscles (LL, GM, and BF) more than others (TB and PM).

Included in

Meat Science Commons



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