关键词: 辣椒, 干燥方式, 表型特征, 挥发性成分, 品质评价

Abstract:

【Objective】In order to provide a theoretical basis for the processing and industrialization of dried capsicum products, the differences of different drying methods on the quality characteristics of capsicum were explored. 【Method】With self breeding MJ7 and MJ8 as test materials, differences in their appearance, nutritional components, and volatile components were analyzed based on 3 different methods: natural drying (ND), hot air drying (HAD), and vacuum freeze drying (VFD), and the topsis method was used for comprehensive evaluation. 【Result】With an overall performance of HAD>ND>VFD, capsicum by VFD had the closest appearance to fresh, and the values of L*, a* (red pepper)/b* (yellow pepper), and C were significantly(P<0.05) higher than those of ND and HAD. The content of HAD dihydrocapsaicin were lowest at 1.82和2.06 g·kg^-1, which was significantly different from ND and VFD (P<0.05). VFD had a a good yield of capsaicin in MJ7 with content of 7.01 g·kg^-1. In contrary to red pepper, yellow pepper had a significant difference(P<0.05) in color value, VFD exhibited a highest value of 2.48, which were twice and 1.84 times higher than that of ND and HAD. HAD retained theirs fat and protein better, while ND and VFD difference were marked. ND had the highest retention of sugars at 41.38 and 35.36 mg·g^-1, which were higher than VFD and HAD for 1.03 and 1.1 times. The crude fiber of both two types capsicums showed no obvious significant difference with content at 20.56%-20.61% and 21.91%-21.95%. Meanwhile, 73 volatile components were identified in two types of capsicums, including esters, ketones, alcohols, aldehydes, acids and terpenes. Volatile components in three types of dried capsicums were the same, esters were the main volatile components in capsicums. But their content was different, ND accounted for 40.35% and 58.66%, while HAD and VFD up to 72%, mainly included Hexyl 2-methylbutanoate (D), Hexyl 2-methylpropanoate (D), and n-octyl acetate (D). The result of cluster analysis was consistent with principal component analysis, the three drying methods of capsicums are classified separately. 19 characteristic differential metabolites were identified by partial least squares analysis, among which Hexyl 2-methylbutanoate (D), Hexyl 2-methylpropanoate (D), Acetic acid butyl ester (D), and 4-Methyl-2-pentanone (D) contributed the most. The topsis comprehensive evaluation analysis showed that VFD was the best in quality performance, followed by HAD, and ND had the worst performance. 【Conclusion】The effects of different drying methods exhibited various influences on the appearance, nutritional components, and volatile components of capsicums. Due to its good performance in overall quality, VFD can be used as an ideal drying method for capsicums.

Key words: Capsicum annuum L., drying methods, phenotypic characteristics, volatile components, quality assessment