Analysis of Main Tea Characteristic Components and Volatile Components and Amino Acid Nutrition Evaluation of Insect Tea from Three Producing Areas in Guangxi

The main tea characteristic components, volatile components and amino acid composition of insect tea from three main producing areas in Guangxi were analyzed in this paper, and the amino acid characteristics and nutritional value were evaluated by amino acid ratio coefficient method. The results showed that Guangxi insect tea was rich in contents and had the characteristics of low caffeine and high amino acid and there were extremely significant differences in water extracts, amino acids and tea polyphenols of insect tea from different producing areas (P<0.01). A total of 36 volatile components were detected of insect tea in three producing areas and there were significant differences among different producing areas. The main volatile components were alcohols and ketones in Rongan, aldehydes and esters in Longsheng, and acids and esters in Sanjiang. In addition, there were great differences in amino acid components of insect tea from different producing areas, among which histidine (His) and glycine (Gly) had significant differences (P<0.05), arginine (Arg), aspartate (Asp) and other 14 amino acids had extremely significant differences (P<0.01). Essential amino acid/total amino acid (EAA/TAA) and essential amino acid/non-essential amino acid (EAA/NEAA) reached the ideal protein essential amino acid pattern proposed by WHO/FAO. Insect tea from three producing areas contained 9 kinds of medicinal amino acids (MAA), and the average value of MAA/TAA was up to 62.26%. According to the amino acid ratio coefficient method, the first limiting amino acid of insect tea was methionine (Met) + cystine (Cys) from three producing areas, and the second limiting amino acid was lysine (Lys) in Longsheng and Sanjiang, and other essential amino acids were close to or higher than model protein. At the same time, the score of ratio coefficient of amino acid (SRCAA) of insect tea from three producing areas ranged from 71.33 to 77.96, and the essential amino acid index (EAAI) was all greater than 1. Thus, it could be seen that Guangxi insect tea was a choice of high-quality protein resources and had the potential to be developed as a health beverage.