Optimization of the Brewing Process and Analysis of Antioxidant Activity and Flavor of Elderberry Wine

Abstract

Fruit wines have high nutritional value and good palatability. However, fruit wine made from a single fruit type does not have good enough flavor and nutritional quality. Therefore, flavorsome fruit wines made from a variety of fruits should be developed as a matter of urgency. In this study, the raw material of elderberry wine was used to explore the production technology of mixed juice wines; the fruits selected were apple, lychee, pear, blueberry, and elderberry. We utilized a single-factor experiment and the response surface method (RSM) approach to optimize the fermentation procedures; the results show that the solid–liquid ratio was 1:7.5, the amount of yeast inoculation was 0.68 g/L, the fermentation temperature was 20 °C, and the added sugar content was 120 g/L. Under these process conditions, a verification test was carried out in a 35 L fermenter. The results showed that the alcohol content, residual sugar content, total acidity, total phenol content, and total flavonoid content of the elderberry wine were, respectively, 7.73% vol, 8.32 g/L, 9.78 g/L, 8.73 mg/mL, and 1.6 mg/mL. In total, 33 volatile components were identified in the resulting elderberry wine. It achieved a harmonious aroma and fruit flavor, a homogeneous and transparent liquid phase, a pleasant taste, and a sensory evaluation score of 95. The antioxidant activity experiments showed that elderberry had a certain antioxidant capacity, and that fermented elderberries had significantly higher antioxidant ability than unfermented ones.

Optimization of the Ginkgo Wine Fermentation Process and Influence of Fermentation Starter Types on the Brewing Flavor

“…The contents of alcohol, total residual sugar, free amino acids, and total acids were determined according to the standard GB/T 15038-2006 "Analytical methods for wine and fruit wine" [15]. After referring to the literature, the total flavonoid content was determined using the spectrophotometric method with aluminum chloride [16].…”

“…The sample preparation was conducted as follows: ginkgo wines fermented with six kinds of fermentation starters were tested. Based on previous research [21], the antioxidant activity was analyzed through DPPH and ABTS + , and some modifications were made [15].…”