超声波与菠萝蛋白酶协同作用对鸭肉嫩化的影响

采用单因素和响应面设计优化了超声波辅助菠萝蛋白酶嫩化鸭肉的最佳工艺参数,并对嫩化机理进行探讨。得到优化条件为处理温度45℃、pH 7.2、菠萝蛋白酶添加量350 U/g、超声波功率80 W、嫩化时间15 min,在该条件下剪切力的预测值为20.208 N,实测值为21.110 N。相对于未处理的鸭肉,嫩化组鸭肉的pH值、持水力和肌原纤维小片化指数显著增加(P0.05),剪切力、肌原纤维溶解度和不溶性胶原蛋白的含量显著下降(P0.05),而色差无明显变化(P0.05)。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳图谱显示嫩化组鸭肉中大分子蛋白被水解成小分子肽类或氨基酸。透射电镜结果显示嫩化组鸭肉肌原纤维Z线断裂溶解,肌节变形缩短,I带和A带模糊不清,出现了肌原纤维小片化现象。超声波与菠萝蛋白酶协同作用对鸭肉的嫩化具有显著的效果,大大缩短了嫩化时间,使鸭肉更加多汁并富有弹性,鸭肉的品质得到了极大的改善。

Effects of Ultrasonic-Assisted Bromelain Hydrolysis on Tenderization of Duck Meat

The use of one-factor-at-a-time method in conjunction with response surface methodology was investigate to optimize the process parameters of ultrasonic-assisted bromelain treatment for tenderizing duck meat. Moreover, the mechanism underlying meat tenderization was explored. The optimized conditions were obtained as follows: temperature 45 ℃, pH 7.2; bromelain concentration, 350 U/g, ultrasonic power 80 W and tenderization time 15 min. Under these conditions, the predicted and measured shear force were 20.208 and 21.110 N, respectively. The tenderized meat presented a significant increase in pH, water-holding capacity and myofibrillar fragmentation index (MFI) and a significant decrease in shear force, myofibrillar protein solubility and insoluble collagen content compared with the untreated meat (P < 0.05), but the color was not significantly changed (P > 0.05). SDS-PAGE results indicated that macromolecular proteins of the treated duck muscle were hydrolyzed into small peptides and/or amino acids. Transmission electron microscopy (TEM) revealed that myofibrillar Z lines were broken and dissolved, sarcomeres were deformed and shortened, with the I and A bands becoming blurred, and myofibrillar fragmentation occurred. Ultrasonic-assisted bromelain treatment had a significant effect on tenderizing duck meat and greatly reduced the tenderization time, and the tenderized meat was juicy and elastic and had greatly improved quality.