Enhancing the fermentation rate and aroma compounds of kiwi wine via the addition of nitrogen during the stationary phase

Abstract

Nitrogen addition is a viable strategy for preventing sluggish or stuck fermentation and enhancing aroma profiles in the winemaking industry. Herein, nitrogen, in the form of amino acids mixture or diammonium hydrogen phosphate (DAP), was added at different fermentation periods to investigate its effects on the fermentation characteristics, non-volatile compounds and aroma profiles of kiwi wines. Both the amino acids mixture and DAP shortened fermentation time by 1–2 days and balanced organic acid proportion by reducing malic acid content and increasing citric acid content. Adding DAP significantly decreased higher alcohols content, whereas higher alcohols content was remarkably increased with amino acids mixture supplementation. Furthermore, nitrogen addition during the stationary phase was most conducive to synthesizing other beneficial aromas, especially acetate esters and medium-chain fatty acid ethyl esters (MCFAEEs), and improving the perception of tropical fruity and cream aromas in kiwi wines. Partial least-squares regression (PLSR) results showed there was a tight correlation between amino acids and volatile compounds. This study provides an insight into the development of high-quality kiwi wine and should serve as the theoretical foundation to support the application of nitrogen addition in the wine industry.