Thermal Modulation of Musalais Wine Characteristics: Volatile Profiles and Chemical Composition at Different Brix...

Area of Science:

• Enology and Viticulture
• Food Chemistry
• Fermentation Science

Background:

• Musalais wine is a traditional Chinese fermented beverage.
• Understanding fermentation parameters is crucial for optimizing wine quality.
• Previous research has not fully elucidated the impact of temperature and grape Brix on Musalais wine's sensory and chemical profiles.

Purpose of the Study:

• To investigate the effects of varying fermentation temperatures (22°C, 25°C, 28°C) and grape juice Brix concentrations (26°, 29°, 32°) on Musalais wine.
• To analyze the resulting changes in physicochemical properties and aroma profiles.
• To identify key volatile organic compounds (VOCs) and their relationship with fermentation conditions.

Main Methods:

• Controlled fermentation experiments manipulating temperature and grape juice Brix.
• Physicochemical analyses including total acidity (TA), residual sugar content (RSC), pH, phenolic content, and anthocyanins.
• Gas Chromatography-Ion Mobility Spectrometry (GC-IMS) for volatile organic compound (VOC) profiling.
• Multivariate statistical analyses (PCA, PLS-DA) and correlation analysis.

Main Results:

• Fermentation temperature significantly affected wine composition: 28°C increased TA and RSC; 22°C enhanced pH, phenolics, and anthocyanins.
• Ethanol content peaked at 25°C, especially with 29 Brix grape juice.
• GC-IMS identified 50 VOCs, with esters, alcohols, and ketones dominating. 22°C fermentation yielded complex, fruity aromas (e.g., ethyl propanoate), while 28°C produced simpler, alcohol-dominant profiles.
• Multivariate analysis distinguished wines based on temperature, identifying key aroma markers.
• Hierarchical clustering grouped wines into 22°C (complex/fruity) and 25-28°C (alcoholic/simpler) categories.

Conclusions:

• Fermentation temperature is a critical factor in determining Musalais wine quality, particularly its aroma complexity and antioxidant properties.
• Optimal conditions for aroma complexity were observed at 22°C, while 25°C offered a balance of ethanol production and antioxidant retention.
• Grape juice Brix levels played a role in modulating wine acidity and sweetness, offering further control over the final product.