T-2毒素对凡纳滨对虾肌肉品质特性和自溶作用强度的影响

摘要

Varied doses of T-2 toxin (T-2),namely 0.0 (control),0.5,1.2,2.4,4.8,12.2 mg/kg,were orally administered to the white shrimp Litopenaeus vannamei for 20 consecutive days.The quality characteristics and autolysis of shrimp muscle were investigated by sensory evaluation,physicochemical analysis and microscopic observation.The results indicated that T-2 exposure significantly affect the color of shrimp muscle.T-2 exposure at low dose could result in a significant increase in hardness and chewiness (P ＜ 0.05),but a significant decrease in hardness,elasticity,cohesiveness,glueyness and chewiness at high dose (P ＜ 0.05).The cooking loss of shrimp muscle first rose and then decrease.Microscopic examination revealed loosening and fragmentation of muscle fibers and wider gaps between muscle fibers,suggesting a decline of shrimp muscle quality.Increasing T-2 exposure resulted in a decrease in amino nitrogen content and an increase in soluble solid content.Soluble protein in shrimp muscle hydrolysate increased first and then decreased (P ＜ 0.05).Myofibril length showed a significant decline with the increase in T-2 (P ＜ 0.05).Electron microscopy confirmed fracture and dissolution of myofibrils,suggesting increased autolysis.%通过以0.0、0.5、1.2、2.4、4.8、12.2 mg/kg T-2毒素微胶囊毒饵料20 d染毒凡纳滨对虾,采用感官评价、理化分析及显微观察法测定T-2毒素对凡纳滨对虾肌肉品质特性和自溶作用强度的影响.结果表明,T-2毒素暴露对生鲜对虾色泽具有显著性影响(P＜0.05),通过理化分析得出低剂量作用时对虾肌肉硬度和咀嚼性明显升高(P＜0.05),随后肌肉组织硬度、弹性、内聚性、胶黏性和咀嚼性显著降低(P＜0.05);肌肉蒸煮损失率呈现先下降后上升趋势,显微结构观察肌纤维间隙不断变大,肌纤维密度下降,肌纤维碎片不断增加,肌肉品质劣化.随T-2毒素暴露剂量升高,氨基态氮溶出量逐渐降低、可溶性蛋白溶出量先升高后降低,可溶性固形物的溶出量显著增加(P＜0.05),肌原纤维长度呈现显著性下降(P＜0.05),扫描电子显微镜下观察肌原纤维断裂严重,自溶强度增加.