南美白对虾射频联合热风干燥工艺优化及对其品质影响

Optimization of Radio Frequency-assisted Hot Air Drying on Penaeus vannamei and Its Effects on the Quality

为了研究射频联合热风干燥对南美白对虾品质的影响,本文基于南美白对虾介电特性,优化对虾射频联合热风干燥工艺,并以热风干燥(hot air drying,HAD)为对照,对比分析射频干燥(radio-frequency drying,RFD)和射频联合热风干燥(radio frequency-assisted hot air drying,RFHAD)对虾干的呈味核苷酸和等鲜量的影响。结果显示,对虾的介电常数和损耗因子随着射频温度和水分含量的升高而增加,更有利于水分的迁移和干燥速率提升。射频穿透深度与水分含量、温度和频率呈负相关。此外,随着叠放层数增加和极板间距缩小,对虾的干燥速率显著增加(P<0.05),综合考虑确立最佳射频干燥条件为对虾叠放四层和极板间距9 cm。同时与HAD相比,RFHAD处理显著提高了虾干中呈味核苷酸和等鲜量(P<0.05),其中等鲜量是HAD组的4.86倍。综上,RFHAD可显著提高虾干的干燥速率,同时提高呈味核苷酸含量,提升虾干滋味和鲜度。

To study the effects of radio frequency-assisted hot air drying(RFHAD)on the quality of South American white shrimp(Penaeus vannamei),the RFHAD process based on the dielectric properties of the shrimp was optimized.The effects of radio frequency drying(RFD)and RFHAD on the flavor nucleotide contents and equivalent umami levels in dried shrimp were compared with those of hot-air drying(HAD).The results showed that as the temperature and moisture content increased,the dielectric constant and loss factor of the shrimp also increased,facilitating moisture migration and enhancing the drying rate.The penetration depth of the RFD was negatively correlated with moisture content,temperature,and frequency.Additionally,increasing the number of stacked layers and reducing the plate spacing significantly increased the drying rate of the shrimp(P<0.05).Considering all these factors,the optimal RFD conditions for shrimp were determined to be the stacking of four layers of shrimp with a plate spacing of 9 cm.Compared with HAD,RFHAD treatment significantly increased the flavor nucleotide contents and equivalent umami levels in dried shrimp(P<0.05),and the equivalent umami levels were 4.86-fold higher than those in the HAD group.In conclusion,RFHAD significantly improved the drying rate of shrimp while increasing the flavor nucleotide content,thereby enhancing the flavor and freshness of dried shrimp.