Bertram Hanne Christine, Aaslyng Margit Dall, Andersen Henrik J
Department of Food Science, Danish Institute of Agricultural Sciences, P.O. Box 50, DK-8830 Tjele, Denmark.
Meat Sci. 2005 May;70(1):75-81. doi: 10.1016/j.meatsci.2004.12.002. Epub 2005 Jan 22.
Low-field NMR T(2) relaxation was measured continuously during cooking of pork samples (m. longissimus dorsi) to a final temperature of 75 °C. Simultaneously the remaining muscle was cooked in an oven to a core temperature of either 62 or 75 °C and subsequently evaluated by a sensory panel. Highly significant effects of final cooking temperature on the sensory attributes juiciness (initial and final), hardness, tenderness, crumbliness and chewing time were found. Juiciness and tenderness decreased with increasing temperature, while hardness, crumbliness and chewing time increased with increasing temperature. Distributed T(2) relaxation data revealed marked effects of temperature (62 vs. 75 °C) on the water distribution within the meat. Partial least squares (PLS) regressions were used to examine a potential prediction of sensory attributes from the distributed T(2) relaxation data, and high correlations were obtained. Moreover, loadings from the PLS regressions were analysed to evaluate the alterations in the water distribution as a function of temperature that contribute to changes in juiciness. This analysis revealed that the reduction in juiciness at 75 °C can be ascribed to changes in the size of the pores confining the myofibrillar water together with an expulsion of water.
在将猪肉样本(背最长肌)烹饪至最终温度75°C的过程中,持续测量低场核磁共振T(2)弛豫。同时,将剩余肌肉在烤箱中烹饪至核心温度62°C或75°C,随后由感官评定小组进行评估。发现最终烹饪温度对感官属性多汁性(初始和最终)、硬度、嫩度、易碎性和咀嚼时间有极显著影响。多汁性和嫩度随温度升高而降低,而硬度、易碎性和咀嚼时间随温度升高而增加。分布式T(2)弛豫数据显示温度(62°C与75°C)对肉内水分分布有显著影响。使用偏最小二乘法(PLS)回归来检验根据分布式T(2)弛豫数据对感官属性进行潜在预测的情况,并获得了高度相关性。此外,分析PLS回归的载荷,以评估作为温度函数的水分分布变化,这些变化导致多汁性的改变。该分析表明,75°C时多汁性的降低可归因于限制肌原纤维水的孔隙大小变化以及水分的排出。