Impact of postponed harvests and withering on the aromas development of Yellow Muscat “fiori d'arancio” berries

The composition of grape berries, and consequently wine characteristics, can be deeply modified by late harvest (LH) or withering (W). Alternatively, a practice called "Poly Double Maturation Reasoned" (PDMR) has been developed, consisting of the cutting of fruit-bearing vines followed by the "reasoned" harvest. PDMR differs from LH or W mainly for what concerns water loss rates and re-programming of berry metabolism. This study aimed to investigate molecular, biochemical, metabolic and sensorial changes in Vitis vinifera cv. Yellow Muscat grape berries subjected to LH, W, and PDMR techniques. Analyses pointed out significant differences in both primary and secondary metabolites. According to gene expression, LH, PDMR, and W berries an up-regulation of genes involved in sugar biosynthesis and a down-regulation of those involved in malate catabolism when compared to traditional harvest (TH) was observed. Transcripts involved in monoterpenes biosynthesis were significantly altered in PDMR berries. Analysis of volatiles indicated that PDMR wines showed levels of linalool and linalool oxides similar to TH ones, while their homovanillic alcohol/acid content was more similar to that of W-wines. Our results suggest that PDMR can be either applied to preserve the typicity of yellow Muscat "Fior d'Arancio" or to produce new wine types.