煮制工艺对中国对虾品质的影响

以多酚氧化酶相对酶活力、水分含量、持水力、虾青素含量、蛋白质含量及提取率、色差、质构、感官评分和扫描电镜等为指标,研究不同煮制工艺(柠檬酸质量浓度和煮制时间)对中国对虾品质的影响。结果表明,随着柠檬酸质量浓度的提高,虾头中多酚氧化酶完全失活的时间逐渐缩短,但柠檬酸质量浓度过高不利于虾体口感,故确定其最优质量浓度为4 g/L。随着煮制时间的延长,虾体中水分含量和持水力均逐渐下降,虾青素含量先上升后下降,总蛋白含量不断下降,其中肌原纤维蛋白和肌浆蛋白在煮制2 min时已大部分变性。煮制过程中,虾体L*值和a*值先升后降,b*值不断上升,硬度、内聚性和咀嚼性不断升高,弹性不断下降。感官评价结果显示,煮制4 min对虾各个单项评分最高,其感官总评分最高。扫描电镜结果表明,煮制过程中对虾肌纤维因受热逐渐发生变性,导致其整齐度下降、纤缝隙增大、维断裂程度加剧。综合上述指标,确定最佳煮制时间为4 min。本研究成果可为虾类制品生产企业完善生产工艺、提升产品品质提供理论依据。

Effect of Cooking on the Quality of Fenneropenaeus chinensis

This study investigated the effect of different cooking conditions(citric acid concentration and cooking time)on the quality of Fenneropenaeus chinensis as evaluated in term of relative activity of polyphenol oxidase,moisture,water-holding capacity,astaxanthin content,protein content and extraction yield,color,texture,sensory evaluation,and scanning electron micrograph.The results showed that the complete inactivation time of polyphenol oxidase in shrimp head was gradually shortened with the increase of citric acid concentration.However,too high citric acid concentration was not conducive to the taste of shrimp,and therefore the optimal concentration was determined to be 4 g/L.With prolonging cooking time,the moisture and water-holding capacity of shrimp muscle decreased gradually,the astaxanthin content increased first and then decreased,and the total protein content declined continuously.Myofibrillar and sarcoplasmic proteins were mostly denatured after 2 min of cooking.During the cooking process,L*and a*values increased first and then decreased,while b*values increased continuously.Hardness,cohesiveness and chewiness increased continuously,while the opposite trend was observed for elasticity.Sensory evaluation results showed that shrimps cooked for 4 min scored highest in sensory scores for each quality attribute and in overall sensory scores.Scanning electron microscopy(SEM)results showed that shrimp muscle fibers were gradually denatured by heating,resulting in a decrease in regularity,an increase in the gap between muscle fibers and aggravation of dimensional breakage.Taken together,the optimum cooking time was determined to be 4 min.The results of this study can provide a theoretical basis for shrimp product enterprises to optimize the production process and to improve product quality in the future.