Effect of Variety and Ripening Stage on Volatile Compounds of NFC Cloudy Apple Juice

In order to explore the effects of variety and late ripening stage on flavor of apple juice, volatile profile of apple juice obtained from five varieties and three late ripening stages were analyzed using headspace solid phase micro-extraction combined with gas chromatography-mass spectrometry followed by multivariate data analysis. The results showed that alcohols (2-methyl-1-butanol, 1-hexanol, etc.), aldehydes (hexanal, E-2-hexenal, etc.) and esters (2-methyl Butyl acetate, etc.) were the main volatile components of apple juice. Variety and late ripening stage had significant effects on the content and composition of key aroma components in apple juice. Granny Smith apple juice had the lowest contents of volatile components among samples and aldehydes were the main volatiles representing green grass flavor; Fuji, Gala, and Golden Delicious apple juices showed similar volatile profile with high amounts of esters, aldehydes, and alcohols. The volatile aroma components of Huashuo apple juice were mainly alcohols and aldehydes, and the whole juice showed a light taste. In addition, during late ripening stages, volatiles clearly changed in apple juice with different varieties. Volatiles of Fuji and Granny Smith apple juice were gradually accumulated and content of respective 28 and 15 volatile compounds increased significantly during late ripening. There was an increased but then decreased trend of volatile contents in Gala and Golden Delicious apple juice. However, Huashuo apple juice showed decreased volatiles contents during late ripening. The outcome of the research on flavor changes of apple cloudy juice could provide theoretical support for raw material selection of cloudy apple juice industry.