ABSTRACT
Coconut (Cocos nucifera Linn.) is a tropical fruit widely cultivated in humid regions, including Benue State, Nigeria, but its perishable nature often leads to substantial postharvest losses. Transforming coconut into wine presents a promising approach to extend shelf life, reduce waste, and diversify fruit-based alcoholic beverages. This study explored the production of coconut wine using Saccharomyces cerevisiae as the fermenting yeast and monitored critical physicochemical and microbial changes throughout the fermentation process. Yeast colony counts peaked at 4.3 × 10³ cfu/ml, while pH decreased from 4.77 at the start to 2.79 after 168 hours, enhancing the competitive advantage of fermentative yeast over spoilage microorganisms. Temperature remained relatively stable, and specific gravity declined progressively over the fermentation period. The resulting wine achieved an ethanol content of 5.81% after 168 hours. Findings suggest that coconut can serve as an effective substrate for wine production, though further research is needed to optimize storage stability and quality under Nigerian tropical conditions.

1.1 Background to the Study
Coconut (Cocos nucifera Linn.) is a perennial fruit produced by the coconut palm, a member of the Arecaceae family. Native likely to Southeast Asia, particularly Malaysia or Indonesia, coconuts are now widely cultivated in tropical regions globally, especially along coastal areas where rainfall and temperature are favorable (Stanley, 2012). The fruit is valued for its nutritional and medicinal properties, particularly young coconut water, which contains sugars, vitamins, minerals, amino acids, and cytokinins with documented anti-aging, anti-cancer, and cardiovascular benefits (Satyabalan, 2011; 2012). Its low-calorie, low-fat, and electrolyte-rich composition makes coconut water a highly functional natural beverage.

Wine production, a process with a rich cultural and historical significance spanning over 6,000 years, has traditionally relied on grapes as the primary substrate. Wine is produced through fermentation by yeasts, predominantly Saccharomyces cerevisiae, which metabolize sugars into ethanol and carbon dioxide, generating complex flavors and aromas (Nikhil et al., 2009; Bisson et al., 2009). Beyond grapes, a range of tropical fruits—including pears, apples, berries, and even flowers—have been explored as alternative substrates for wine production, especially in regions where grapes are scarce (Okunowo et al., 2005; Alobo & Offonry, 2009). The transformation of perishable fruits into wine not only preserves the fruit but also enhances its economic and nutritional value.

The microbial ecology of wine fermentation is complex and critical to product quality. While S. cerevisiae drives alcoholic fermentation, lactic acid bacteria (LAB) contribute to malolactic conversion, impacting acidity, flavor, and aroma. The growth of unwanted microorganisms can result in spoilage, off-flavors, or microbial hazes, highlighting the importance of monitoring physicochemical and microbiological parameters during fermentation (Sponholz, 1993; Delfini & Formica, 2001). In coconut wine production, understanding yeast population dynamics, pH shifts, alcohol content, and other quality indicators is essential to developing a safe, stable, and flavorful product.

Fermentation is the anaerobic conversion of sugars into simpler compounds, primarily ethanol and carbon dioxide, through the action of microorganisms. Glycolysis generates pyruvate from glucose, which is subsequently metabolized to ethanol in the absence of oxygen:
C?H??O? → 2 C?H?OH + 2 CO?
This process provides energy under anaerobic conditions and forms the basis for alcoholic beverage production (Robinson, 2006). Factors such as substrate type, yeast strain, cultivation conditions, and postharvest handling significantly influence fermentation efficiency and final wine quality (Daudt & Ough, 1973; Bell et al., 1979; Liu, 2002).

Yeast, particularly Saccharomyces cerevisiae, is central to fermentation processes in food and beverage production. This eukaryotic microorganism can ferment glucose and sucrose, requires minerals such as phosphate and potassium for metabolic function, and thrives in both aerobic and anaerobic environments (Monk, 1994; Kudo et al., 1988; Martini, 1993). Its nutritional profile—rich in B-complex vitamins, essential minerals, and protein—further enhances the value of yeast-fermented beverages (Griffith, 2000). Industrial utilization of yeast includes the production of bread, beer, wine, and ethanol, emphasizing the organism’s versatility and importance.

Tropical fruits, including coconut, offer substantial potential for value-added wine production. Studies have demonstrated successful fermentation of palm sap and other tropical fruit juices into alcoholic beverages, with yeast isolates from palm wine exhibiting robust ethanol production and fermentation efficiency comparable to commercial strains (Chilaka et al., 2010; Nwachukwu et al., 2006). Coconut, often underutilized in Nigeria, can thus be transformed into a nutritionally enriched and economically viable product through controlled fermentation using S. cerevisiae.

1.2 Aim of the Study
This research aims to evaluate the feasibility of producing high-quality wine from coconut fruit using Saccharomyces cerevisiae and to monitor the associated physicochemical and microbial changes during fermentation.