The effects of porcine somatotropin administration and gender on cooking properties and palatability attributes of pork muscle

Abstract

Loin roasts and ham steaks from 120 Yorkshire pigs (60 barrows and 60 gilts) were utilized to evaluate the effects of porcine somatotropin (PST) treatment and gender on cooking properties and palatability attributes. Within each gender, pigs were randomly allocated to the following three treatments: 1) control, 2) prolonged-release PST implants (2 mg d−1), or 3) daily subcutaneous PST injections (2 mg d−1). All animals received a 17% crude protein diet, ad libitum. Animals received PST treatments within a body weight range of 70 ± 5 kg to 96 ± 5 kg. All animals were slaughtered and processed using simulated commercial procedures. Longissimus lumborum (loin) roasts (lumbar) and cured and smoked semimembranosus (SM) steaks were roasted to 75 and 60 °C, respectively, in a 177 °C oven, sub-sampled, and evaluated by an eight-member sensory panel. No differences in cooking properties or palatability attributable to gender were observed (P > 0.05). However, cured and smoked SM steaks from pigs receiving daily PST injections were more tender both initially and overall (P < 0.05) than their counterparts from control pigs. In addition, cured and smoked SM steaks from pigs receiving daily PST injections had less perceived connective tissue (P < 0.05) than their counterparts from control pigs and pigs receiving prolonged-release PST implants. The cooked loins from pigs receiving prolonged-release PST implants were perceived to contain less connective tissue than their counterparts from control pigs and pigs receiving daily PST injections (P < 0.05), but cooked loins from pigs receiving prolonged-release PST implants had less-desirable flavour (P < 0.05) than their counterparts from pigs receiving daily PST injections. It should be noted, however, only the tenderness differences observed in the cured and smoked SM were of sufficient magnitude to be of practical importance. Consequently, it would appear PST treatments, particularly daily injections, can be utilized to achieve previously reported, potential production and carcass composition advantages, while possibly improving the eating quality of some pork products. Key words: Pork, somatotropin, PST, gender, cooking properties, palatability attributes