微波加热对小龙虾品质的影响

为了挖掘微波在小龙虾热加工中的应用潜力,本文以水煮小龙虾为对照,通过热成像温度分析、摄影图像色泽分析、质构和脱壳完整率分析以及感官分析等方法,全面地分析了不同功率密度的微波加热对小龙虾品质(色泽、质构、脱壳完整率、质量损失等)的影响。结果表明,小龙虾在微波加热过程中的温度和表壳色泽分布不均,但高功率密度和长时间的微波加热有利于小龙虾温度和橘红色泽分布趋于均匀,其中5 W/g微波加热4.5和5.5 min的小龙虾外观评分分别与水煮4.5和5.5 min的小龙虾无显著性差异。随微波加热时间和功率密度的增加,小龙虾的质量损失和虾肉的水分流失随之增加,进而影响了虾肉的质构特性、剪切特性、挤压损失和口感。对于不同功率密度的微波加热,小龙虾虾尾的口感与其质构特性和剪切特性间的相关性存在差异,其中虾尾的口感与虾尾表面硬度、紧实度、含水量和挤压损失呈正相关,与虾尾剪切力、剪切能呈负相关。此外,3 W/g微波加热3.5 min的虾尾口感评分最高,且与水煮3.5 min的虾尾口感无显著差别,但非水环境下微波加热的小龙虾比水煮小龙虾更容易脱水且更难脱壳,这使得微波加热的小龙虾虾尾的形态和色泽较水煮更差。随着微波加热时间或功率密度的增加,微波小龙虾虾尾的L^*和b^*值有所增加,但虾尾的a^*值下降且脱壳完整率的改善不明显。综上,微波在小龙虾的热加工中具有一定应用潜力。

Effects of Microwave Heating on the Quality of Crayfish

To reveal the potential application of microwave in the thermal processing of crayfish,the effects of microwave heating with different power densities on the qualities(color,texture,shelling integrity,mass loss,etc.) of crayfish were investigaled by the thermal imaging analysis,photographic image analysis,texture and shelling integrity analysis and sensory analysis,etc.. The results showed that the temperature and shell color of crayfish were non-uniform during microwave heating,but the uniformity could be improved by increasing the heating time or microwave power. There was no significant difference between the appearance scores of crayfish heated for 4.5 and 5.5 min at 5 W/g and those boiled with water for 4.5 and 5.5 min. However,the mass loss and moisture loss of crawfish increased with the power density and time of microwave heating,and thus affected the texture,shear properties,expressible moisture and taste of crayfish tail. There were different correlations between the taste of crayfish tail and the texture or shear properties for the microwave heating with different power density. Among them,the taste of crayfish tail was positively related to the surface hardness,compactness,moisture content and expressible moisture of crayfish tail,and negatively related to the shear force and shear energy of crayfish tail. Furthermore,the crayfish tail heated for 3.5 min at 3 W/g had the highest taste score and no significant difference with the crayfish boiled for 3.5 min,but it was more difficult for the crayfish heated by microwave in non-aqueous environment to shuck and keep moisture than boiled crayfish,and thus the tail shape and skin color of the former were worse than the latter. Although the value of L* and b* of crayfish tail increased with the increasing of microwave heating time or power density,the value of a* of the crayfish tail decreased and the ratio of intact tail did not improve significantly. In a word,microwave had potential application in the thermal processing of crayfish,but it also exposed some shortcomings.