Abstract:

This study investigated the utilization of waste Tea Leaf Fibre Extract (TLFE) as a natural colorants and functional additive in the formulation of three indigenous Nigerian beverages: Kunu-zaki, Tiger Nut Milk, and Ginger Extract. The primary objective was to assess the impact of TLFE on the sensory properties, physicochemical stability, alcoholic content, and microbial quality of these composite beverages, thereby promoting the reuse of agricultural waste. TLFE was obtained using three methods: Infusion, Maceration, and Soxhlet. The Soxhlet extraction method proved to be the most efficient, yielding the highest percentage (26.42 %), compared to Maceration (21.92 %) and Infusion (12.75 %). Three optimized beverage composites were subjected to comprehensive quality assessments. Sensory analysis, conducted using a 9-point hedonic scale, indicated a distinct consumer preference for the TLFE-Tiger Nut Milk (TL-TN) composite, which consistently received the highest mean scores for Overall Acceptability, Aroma, Flavour, and Smoothness. Conversely, the TN-TL composite was the least favored. Microbiological assays showed that all control beverages had microbial loads in the 105 CFU/mL range, except for Ginger, which showed “No growth” due to inherent antimicrobial properties. The composites showed variability, with high bacterial counts in the Tiger Nut Milk-TLFE (9.0 × 106 CFU/mL at 1:1) and Ginger-TLFE (19.1 × 106 CFU/mL at 1:5) variants, indicating potential spoilage issues at these ratios. Critically, the Ginger-TLFE 5:1 ratio proved to be the most microbiologically stable formulation, resulting in “No growth,” confirming the potent inhibitory effect of high ginger concentration. Furthermore, all formulated beverages were classified as non-alcoholic, exhibiting very low Alcohol by Volume (ABV) content ranging from 0.06 % to a maximum of 0.88 %. Alcohol production correlated positively with the proportion of the base ingredient (fermentable sugars) and was reduced when TLFE acted as a diluent. The findings demonstrate that TLFE successfully serves as a functional colorant and stabilizing agent, supporting the development of novel, quality-enhanced, and microbiologically stable indigenous beverages, particularly highlighting the potential of the TL-TN blend for sensory appeal and the Ginger-TLFE 5:1 blend for enhanced shelf-life.