Effects of diammonia phosphate addition on the chemical constituents in lychee wine fermented with Saccharomyces cerevisiae

This study evaluated the effects of diammonia phosphate (DAP) on the non-volatile and volatile compounds of lychee wine fermented with Saccharomyces cerevisiae, when added in two different quantities (0.5 mmol/L and 1.5 mmol/L). It was found that DAP supplementation improved the utilization of ammonia and inhibited the consumption of proline and valine, which regulated the production of alpha-ketoglutaric, succinic and fatty acids. The addition of 0.5 mmol/L DAP improved the rate of sugar catabolism by slightly increasing yeast growth, thus inducing a higher production of glycerol than of ethanol. Additionally, more odor-active terpene derivatives (trans-beta-damascenone, o-cymene, delta-guaiene) in lychee juice were retained after the fermentation added with 0.5 mmol/L DAP. However, the addition of 1.5 mmol/L DAP slowed rates of sugar metabolism and glycerol production, and significantly enhanced the production of acetic acid. Furthermore, with the exception of limonene, the higher DAP addition did not retain more terpene derivatives. These findings, therefore, suggest that a moderate addition of DAP could enhance the flavorful character of lychee wine.