Spice and Beverage Research Institute, CATAS, Wanning 571533, China.
College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
Molecules. 2019 Jul 31;24(15):2781. doi: 10.3390/molecules24152781.
This paper compares the differences in metabolites of vanilla beans at five different curing stages. Key vanilla flavors, vanillin precursors and main enzymes during the curing process of Hainan vanilla beans were also analyzed. Hundreds of metabolites were detected based on metabolic analyses of a widely targeted metabolome technique, compared with blanched vanilla beans (BVB), sweating vanilla beans (SVB) and drying vanilla beans (DVB), the total peak intensity of cured vanilla beans (CVB) is on the rise. The score plots of principal component analysis indicated that the metabolites were generally similar at the same curing stages, but for the different curing stages, they varied substantially. During processing, vanillin content increased while glucovanillin content decreased, and vanillic acid was present in sweating beans, but its content was reduced in drying beans. Both -hydroxybenzaldehyde and -hydroxybenzoic acid showed the maximum contents in cured beans. Ferulic acid was mainly produced in drying beans and reduced in cured beans. -coumaric acid increased during the curing process. Vanillyl alcohol in drying beans (0.22%) may be formed by the hydrolysis of glucoside, whose conversion into vanillin may explain its decrease during the curing stage. β-Glucosidase enzymatic activity was not detected in blanched and sweating beans, but was observed after drying. Peroxidase activity decreased during curing by 94% in cured beans. Polyphenol oxidase activity was low in earlier stages, whereas cellulase activity in processed beans was higher than in green beans, except for cured beans. This study contributes to revealing the formation of flavor components and the biosynthesis pathway of vanillin.
本文比较了 5 个不同干燥阶段香草豆的代谢物差异。还分析了海南香草豆在干燥过程中的关键香草风味、香草醛前体和主要酶。基于广泛靶向代谢组学技术的代谢分析，检测到数百种代谢物，与烫漂香草豆（BVB）、发汗香草豆（SVB）和干燥香草豆（DVB）相比，处理过的香草豆（CVB）的总峰强度呈上升趋势。主成分分析的得分图表明，在相同的干燥阶段，代谢物通常相似，但对于不同的干燥阶段，它们有很大的差异。在加工过程中，香草醛含量增加，而葡香草醛含量降低，香草酸存在于发汗豆中，但在干燥豆中含量减少。-羟基苯甲醛和-羟基苯甲酸的含量均在处理过的豆中达到最大值。阿魏酸主要在干燥豆中产生，并在处理过的豆中减少。-香豆酸在干燥过程中增加。干燥豆中的香草醇（0.22%）可能是糖苷水解形成的，其在干燥阶段的转化可能解释了其含量的减少。在烫漂和发汗豆中未检测到β-葡萄糖苷酶酶活性，但在干燥后观察到。过氧化物酶活性在处理过的豆中下降了 94%。多酚氧化酶活性在早期阶段较低，而加工豆中的纤维素酶活性高于绿豆，除了处理过的豆。本研究有助于揭示风味成分的形成和香草醛的生物合成途径。
