蒸煮牡蛎肉的蛋白酶解特性及风味特征的研究

Enzymatic properties and flavor characteristics of cooked oyster(Crassostrea gigas)

利用酶解法制取牡蛎生物活性肽已受到广泛关注,然而新鲜牡蛎易在酶解过程中发生风味劣变,导致制备的牡蛎肽风味较差。研究首次采用蒸煮开壳获得牡蛎肉,分析4种蛋白酶(风味蛋白酶、木瓜蛋白酶、菠萝蛋白酶、碱性蛋白酶)的酶解特性及其酶解产物的风味特征。结果发现,牡蛎肉的酶解特性与其酶解产物的风味受酶解时间和酶种类的影响,水解度(DH)和可溶性蛋白含量随酶解时间的延长先迅速增加后增势变缓,其中碱性蛋白酶的水解度(DH)、可溶性蛋白含量均显著高于其他处理组(P<0.05);酶解产物的感官评分随酶解时间延长而下降,其中菠萝蛋白酶酶解产物在1h后口感和整体可接受度显著下降,而碱性蛋白酶酶解产物在酶解1.5h后口感评分显著下降,木瓜蛋白酶和风味蛋白酶酶解产物在酶解2h后显著下降。此外,酶解产物的TBARS随酶解时间不断增加,酶解1h后,木瓜蛋白酶和碱性蛋白酶酶解产物的TBARS值显著高于风味蛋白酶和菠萝蛋白酶(P<0.05)。利用电子鼻和固相微萃取气相色谱联用(SPME-GC-MS)进一步分析碱性蛋白酶酶解过程中挥发性风味成分的变化,发现醇类和醛类物质相对含量降低,酮类和烃类物质相对含量增加,这可能与其酶解过程中风味改变有关。

Fresh oysters are easily deteriorated during enzymatic hydrolysis and processing, this research was conducted to analyze the enzymatic properties and flavor characteristics of the oyster meat obtained by steamed the whole oyster. The results showed that the flavor in the enzymatic hydrolysis process was affected by the type of enzyme and the time of enzymatic hydrolysis. The degree of hydrolysis(DH) and soluble protein content both showed rapidly increase at the preliminary stage and then become slowly with the enzymatic hydrolysis time, what’s more, the degree of hydrolysis(DH) and soluble protein content of alkaline protease hydrolysate were much higher than those of other treatment groups(P<0.05). The sensory scores of four proteases(flavor protease, papain, bromelain, alkaline protease) were greatly decreased with the prolongation of enzymatic hydrolysis time, and the bromelain was significantly decreased after 1 h of enzymatic hydrolysis, and alkaline protease decreased significantly after 1.5 h of enzymatic hydrolysis, papain and flavor protease decreased significantly after 2 h of enzymatic hydrolysis. Lipid oxidation gradually increased during enzymatic hydrolysis, especially after almost 1 h, the TBARS values of papain and alkaline protease were significantly higher than that of flavor protease and bromelain(P<0.05). Furthermore, the analysis of electronic nose and solid phase microextraction gas chromatography-mass spectrometry(SPME-GC-MS) showed that the relative contents of alcohols and aldehydes decreased but ketones and hydrocarbons increased. This may be related to the change in flavor during the enzymatic hydrolysis process.