ABSTRACT
Yogurt is a widely consumed fermented dairy product, but due to increasing cases of lactose intolerance, dairy allergies, and a shift toward plant-based diets, the demand for non-dairy alternatives has risen significantly. This study aimed to develop and evaluate the chemical composition, sensory attributes, and mineral content of vegan tigernut yogurt, a potential lactose-free dairy substitute. Tigernut (Cyperus esculentus), a nutrient-dense tuber widely consumed in Nigeria, offers high levels of carbohydrates, dietary fiber, healthy fats, and essential minerals. Fresh tigernuts were purchased from a market in Benin City, Edo State, Nigeria. The tigernut milk was extracted through soaking, blending, and filtration before being pasteurized at 73°C and cooled to 45°C for fermentation. The study employed a Completely Randomized Design (CRD), with six treatment groups, each replicated three times. Fermentation was conducted using five different starter cultures alongside a control sample of unfermented tigernut milk: Lemon (T1) – Natural source of lactic acid bacteria (LAB). Fermented Cabbage (T2) – Contains Lactobacillus plantarum and Leuconostoc mesenteroides. Commercial Yogurt Starter (T3) – Contains Lactobacillus bulgaricus and Streptococcus thermophilus. Chili Pepper (T4) – Natural LAB source with antimicrobial properties. Tsamiya (Tamarind) (T5) – Rich in organic acids that aid fermentation. Raw Tigernut Milk (T6, Control) – Unfermented sample for comparison. Fermentation was carried out for 12 to 18 hours under controlled conditions. Proximate analysis revealed significant variations (p<0.05) in ash, fat, moisture, nitrogen-free extract (NFE), and protein content among treatments. Raw Tigernut Milk (T6) exhibited the highest protein (2.407%) and NFE (8.650%) content, while Chili Pepper (T4), Tsamiya (T5), and Tigernut Milk (T6) had the highest ash content, indicating superior mineral retention. Fat content was highest in Tigernut Milk (T6) (8.507%), while Fermented Cabbage (T2) had the highest moisture content (84.24%), suggesting that specific fermentation methods influenced nutritional composition and texture.Mineral analysis indicated significant (p<0.05) differences in calcium (Ca), potassium (K), and phosphorus (P) concentrations. Tigernut Milk (T6) recorded the highest potassium (0.1457 mg/g) and phosphorus (0.1363 mg/g) levels, while Lemon (T1) had the highest calcium content (0.10688 mg/g). The pH analysis showed that all samples were within the acceptable acidic range for yogurt (4.00–4.25). Fermented Cabbage (T2) and Tsamiya (T5) had the lowest pH (4.00), indicating higher acidity due to lactic acid formation, while Lemon (T1) had the highest pH (4.25), likely due to its citric acid buffering capacity. Sensory evaluation, conducted using a 5-point hedonic scale, assessed aroma, flavor, texture, aftertaste, and overall acceptability. Lemon (T1) emerged as the most preferred treatment, receiving scores between 3.3 and 4.4, while Fermented Cabbage (T2) consistently scored the lowest, indicating a less favorable sensory profile. Statistical analysis confirmed significant differences (p<0.05) in sensory attributes, emphasizing the impact of fermentation on consumer perception. Overall, this study demonstrates that tigernut yogurt is a promising plant-based dairy alternative, offering high nutritional content, improved sensory appeal, and desirable mineral composition. The findings suggest that treatment variations significantly influenced proximate and mineral composition, as well as sensory attributes, highlighting the importance of optimization in developing a nutritionally rich and consumer-acceptable plant-based yogurt. The results suggest that optimizing certain treatments, particularly Lemon (T1) and Commercial Yogurt Starter (T3) could lead to the development of a nutritionally enhanced and consumer-preferred product
