A combination of physiological and chemometrics analyses reveals the main associations between quality and ripening traits and volatiles in two loquat cultivars

A combined analysis of physiological traits, volatile composition and sensory evaluation of aromatic quality was conducted on the 'Algerie' and 'Golden Nuggett' cultivars at six maturity stages, covering colour breaking to complete ripening. The main difference between cultivars during ripening was aromatic character; organoleptic differences between cultivars were assessed by a taste panel and could be explained by the volatile profile at harvest, and more specifically by those volatiles showing a rapid increase as fruits fully ripened. Among the 121 volatile compounds identified in loquat fruits, 2-methyl butanoic acid was the only cultivar-specific VOC, detected only in 'Algerie', while the levels of other common VOCs also contributed to differentiation between cultivars. A correlation analysis ran between volatile compounds levels and loquat aroma and flavour intensity revealed that 1,2-dimethoxy-4-(2-methoxyethenyl)benzene, elemicin, (Z)-2-hexen-1-ol, methyl 2-methylbutanoate, methyl 3,4,5-trimethoxybenzoate, cis-geranylacetone, (E)-methyl cinnamate, (E)-2-decenal, cis-edulan and 1-hydroxycyclohexyl phenyl ketone were volatiles which could importantly contribute to loquat's aromatic character, some of which are reported here for the first time as key volatiles in aromatic quality. The correlations among the physiological parameters, the volatile compounds and physiological traits, and the parallelisms between precursors and volatile product, are discussed as they offer clues about loquat quality-associated metabolic changes during ripening.