Ruiz-Ramírez J, Arnau J, Serra X, Gou P
Institut de Recerca i Tecnologia Agroalimentàries (IRTA), Unitat de Tecnologia i Enginyeria de Processos, Centre de Tecnologia de la Carn, Granja Camps i Armet s/n, 17121 Monells, Girona, Spain.
Meat Sci. 2006 Feb;72(2):185-94. doi: 10.1016/j.meatsci.2005.06.016. Epub 2005 Aug 24.
The aim of the present study was to determine the effect of pH level and NaCl content on the relationship between water content and texture parameters in semimembranosus and biceps femoris muscles in dry-cured ham. The experiment was undertaken using 18 hams, selected in a commercial slaughterhouse. Half of the hams had a pH<5.7 and the rest a pH>6.2, measured in the semimembranosus muscle at 24-h post mortem (pH(SM24)). The hams were treated with 20, 50 or 80g of NaCl per kg of ham. At the end of the aging process nine samples from semimembranosus and biceps femoris muscles were dried to different levels of water content covering the range from 22.4% to 58.5%. At the end of the drying period, a Texture Profile Analysis was used to determine textural parameters. Samples from biceps femoris muscle and samples from hams with low pH(SM24) showed a higher proteolysis index (100×non-protein nitrogen/total nitrogen) than samples from semimembranosus muscle and samples from hams with high pH(SM24), respectively. The proteolysis index decreased when the added NaCl amount increased. The proteolysis index was the parameter that best explained the modifications in the relationship between water content and the texture parameters (hardness, cohesiveness and springiness) of dry-cured ham muscles and it would be considered in order to predict the texture in dry-cured ham at different drying levels. Dry-cured hams with a lower proteolysis index were more prone to present harder texture at low water contents, which is typical of hams with crustiness problems.
本研究的目的是确定pH值水平和NaCl含量对干腌火腿半膜肌和股二头肌中水分含量与质地参数之间关系的影响。实验使用了在一家商业屠宰场挑选的18只火腿。一半火腿的pH值<5.7，其余火腿的pH值>6.2，在宰后24小时测量半膜肌中的pH值（pH(SM24)）。火腿用每千克火腿20、50或80克NaCl进行处理。在成熟过程结束时，从半膜肌和股二头肌中取九个样本，干燥至不同的水分含量水平，范围从22.4%到58.5%。在干燥期结束时，使用质地剖面分析来确定质地参数。股二头肌样本和pH(SM24)低的火腿样本的蛋白水解指数（100×非蛋白氮/总氮）分别高于半膜肌样本和pH(SM24)高的火腿样本。当添加的NaCl量增加时，蛋白水解指数降低。蛋白水解指数是最能解释干腌火腿肌肉中水分含量与质地参数（硬度、内聚性和弹性）之间关系变化的参数，为预测不同干燥水平下干腌火腿的质地，应考虑该参数。蛋白水解指数较低的干腌火腿在低水分含量时更易呈现较硬的质地，这是有硬皮问题火腿的典型特征。
