Effects of post-harvest fungal infection of apples on chemical characteristics of cider.

The impact of fungal post-harvest infection of apple on the chemical composition of cider was investigated through a comparative analysis of ciders obtained from apples (Gala variety) separately infected by five fungal species (Alternaria alternata, Botrytis cinerea, Diplodia seriata, Monilinia fructigena, and Penicillium expansum) and cider from sound apples. The content of several flavor-active molecules belonging to different chemical groups, such as alcohols, esters, acids, aldehydes, phenols, and lactones, significantly varied among ciders. Particularly, cider from sound apples had a higher concentration of ethyl ester acetate, fatty acid ethyl esters and fatty acids, molecules that contribute to fruity and sweet scent. Principal component analysis well discriminated ciders, evidencing species-specific fungal effect. Differences in precursor availability in juices and biosynthesis pathways in fungi could explain changes in aroma profile of ciders. This study provides information on the potential risk to produce cider from infected apples due to the possible quality depreciation.