Research Progress of Aroma Compounds in Litchi Fruit and Its Processed Products

Abstract

As an important secondary metabolite, aroma endows litchi fruit with unique flavor quality, and it is one of important indexes to evaluate the quality of fresh litchi fruit and its processed products. The studies on litchi aroma components mainly focused on the composition and content identification of volatile substances. With the development of detection methods, headspace solid-phase micro-extraction (HP-SPME) with Gas Chromatogram-Mass Spectrum (GCMS) technology is mainly used for the researches of aroma components of litchi fruits currently, and a variety of volatile components have been identified, such as terpenes, esters, aldehydes, alcohols, acids, phenols and etc., among which terpenes are the main aromatic substances. According to the differences in precursors, the aroma synthesis pathway is divided into terpenoid metabolism, amino acid metabolism and fatty acid metabolism, however, there are few studies on the biosynthesis pathway of aroma components in litchi fruit. Here we review the extraction and detection techniques of volatile substances of litchi fruit and its processed products at home and abroad, the types and components of aroma substances, biosynthesis pathway and the effects of processing technology and post-harvest treatment on the contents of aroma substances. The research direction of aroma substances in litchi fruit is prospected, which will provide scientific theoretical support for the research of litchi fruit flavor quality, and provide a reference for the selection and breeding of excellent litchi varieties and the development of high-quality processed products.

Keywords

• litchi
• aroma substances
• extraction method
• processed product
• metabolism