Effect of Cooking Method on the Texture of Epimysial Tissue and Rancidity in Beef Roasts

Abstract

Twelve top round roasts from two Utility-grade cows were randomized and cooked by microwave, convection or conventional methods after epimysial tissue had been inserted into each roast. The freshly cooked and stored roasts were evaluated for rancidity using three TBA methods, and textural determinations were made on epimysial tissue. TBA numbers increased from day 0 through day 11. Shear values for epimysial tissue from S-year old animals cooked by microwave tended to be lower than those for tissues cooked by convection or conventional methods, but no differences in cooking method were observed for tissue from l-year old animals.

Thermal Processing

“…Increased gel strength is paralleled by a decrease in soluble protein. Welke et al (1986) observed increased weights of epimysial connective tissue after cooking, indicating hydration and hydrolysis of the collagen. No further decrease in water soluble fraction when held.…”

“…Welke et al (1986) reported roasts cooked by microwave took less time to reach endpoint temperatures than did roast cooked by convection or conventional methods. Welke et al (1986) reported roasts cooked by microwave took less time to reach endpoint temperatures than did roast cooked by convection or conventional methods.…”

“…Increasing internal temperature results in increased gel strength (Barbut et al 1996 ). Hamm and Deatherage, 1960 ;Lyon et al, 1986 ;Barbut et al, 1996 40 -60 ° C Reduction in solubility of myofi brillar fraction Leander et al, 1980 63 ° C Slight disfi gurement of the myofi bril, some swelling of the perimysial connective tissue 68 ° C Swelling of the A -band, connective tissue coagulated 73 ° C Sarcomeres contraction and breakage at Z -line, Coagualtion of sarcolemma, increased loss of sarcomeric structure Bendall and Restall, 1983 40 -90 ° C Decreased myofi ber diameter Martens et al, 1982 53 -63 ° C Denaturation of collagen, breaking up of fi brous structure Welke et al, 1986 Increased epimysial connective tissue with cooking cluded that the change in volume was mostly due to moisture loss. Changes in gel structure can be Laakkonen et al, 1970 45 -58.5 ° C Hold at 60 ° C Rapid decrease in water soluble fraction of meat.…”

Microwave processing of meat

“…Microwave oven cooking tends to retain higher amounts of vitamins such as retinol, thiamin, and riboflavin compared with earth-ovencooked meat. The difference in vitamin retention could be due to a higher cooking temperature of earth-oven cooking compared with microwave cooking (Welke et al, 1986;Kumar & Aalbersberg, 2006;Zhang et al 2006). In cooking process, the contractile proteins of meat (myosin and actin) will denature and the connective tissue (collagen) under goes to solubilize.…”