Janz J A M, Morel P C H, Purchas R W, Corrigan V K, Cumarasamy S, Wilkinson B H P, Hendriks W H
Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand.
J Anim Sci. 2008 Jun;86(6):1402-9. doi: 10.2527/jas.2007-0437. Epub 2008 Feb 29.
Pork from the LM and semimembranosus muscle (SM) of 59 female Duroc-cross pigs with a mean carcass weight of 80.1 kg (SD = 3.2) were assessed for quality. The pigs were grown on diets containing either animal and plant products (the animal group) or plant products only (the plant group), with or without a supplement (0.31% of the diet) containing extra CLA, selenium, and vitamin E. The 45-min postmortem pH of LM was unaffected by dietary treatment (mean 6.44, SD = 0.21), but the ultimate pH (pHu) was lower for the supplemented animal group for both muscles within the animal group (P < 0.04). Water-holding capacity in terms of drip loss for SM and expressed juice levels for LM, but not cooking loss, was also lower for the supplemented animal group (P < 0.01), but this difference was reduced after adjustment to a constant pHu (P < 0.07). Warner-Bratzler shear force (WBSF) values were greater for the plant group for LM only (P < 0.05), both before and after pHu adjustment. Differences between dietary treatment groups for color (L*, a*, and b*) were small and seldom significant before or after pHu adjustment. Sensory assessment of LM samples (with 5% subcutaneous fat added) from 32 pigs (8 per group) for 8 odor notes and 11 flavor notes by a trained analytical sensory panel of 13 people revealed no differences between the groups, except that the percentage of instances in which a rancid odor was detected was greater for the supplemented plant group compared with the control plant group (25 vs. 12%). Differences (P < 0.001) were shown between the muscles such that, relative to SM, LM had lower pHu values, greater drip losses, greater WBSF values, greater L* values, and lower chroma values, but similar levels of cooking loss. It is concluded that the dietary treatments imposed to improve the nutritional value of pork had some effects on certain meat quality parameters, but that the overall effects on appearance and palatability were small and unlikely to be of practical importance.
对59头平均胴体重为80.1千克（标准差=3.2）的杜洛克杂交母猪的腰大肌（LM）和半膜肌（SM）猪肉进行了品质评估。这些猪分别饲喂含动物和植物产品的日粮（动物组）或仅含植物产品的日粮（植物组），部分日粮添加了含额外共轭亚油酸（CLA）、硒和维生素E的补充剂（占日粮的0.31%）。腰大肌宰后45分钟的pH值不受日粮处理的影响（平均值6.44，标准差=0.21），但动物组中添加补充剂的动物组两种肌肉的最终pH值（pHu）较低（P<0.04）。添加补充剂的动物组半膜肌的滴水损失和腰大肌的表达汁液水平所表示的持水能力较低，但熟损失不低（P<0.01），但在调整到恒定pHu后，这种差异减小（P<0.07）。仅腰大肌的Warner-Bratzler剪切力（WBSF）值在pHu调整前后，植物组均较高（P<0.05）。日粮处理组之间颜色（L*、a和b）的差异较小，在pHu调整前后很少有显著差异。由13人组成的经过训练的分析感官小组对32头猪（每组8头）的腰大肌样本（添加5%皮下脂肪）的8种气味特征和11种风味特征进行感官评估，结果显示各组之间没有差异，只是添加补充剂的植物组检测到酸败气味的比例高于对照植物组（25%对12%）。两种肌肉之间存在差异（P<0.001），相对于半膜肌，腰大肌的pHu值较低、滴水损失较大、WBSF值较大、L*值较大、色度值较低，但熟损失水平相似。得出的结论是，为提高猪肉营养价值而采用的日粮处理对某些肉质参数有一些影响，但对外观和适口性的总体影响较小，不太可能具有实际重要性。
