IMPACT OF GALACTURONIC AND CITRIC ACID TREATMENTS ON THE PHYSICOCHEMICAL PARAMETERS AND SENSORY QUALITY OF TIGER NUT (Cyperus esculentus L.) MILK

The increasing demand for plant-based milk alternatives has driven interest in improving the quality and shelf life of tiger nut (Cyperus esculentus L.) milk. This study investigated the effects of citric and galacturonic acid treatments on the sensory attributes, pH, and reducing sugar content of tiger nut milk. Citric acid was extracted from ripe sweet oranges via ethanolic immersion and thermal agitation, whereas galacturonic acid was obtained through enzymatic hydrolysis of pectin using pectinase at 40°C for 2 hours. The acids were applied at varying concentrations (0.1–0.5 mg/ml), and the treated samples were evaluated over 120-hours. Sensory evaluation revealed moderate consumer preference, with 60–70% of the panellists rating the colour, flavour, taste, aroma, and overall acceptability. Both acids significantly (p<0.05) influenced the physicochemical properties of milk. Higher concentrations (0.3–0.5 mg/ml) induced a pronounced reduction in pH, from an initial value of 6.30 to as low as 2.56 after 120 hours, while simultaneously increasing the reducing sugar content in a dose-dependent manner. Significant differences (p<0.05) in reducing sugar levels were observed in samples treated with ≥0.3 mg/mL of Citric and galacturonic acid, whereas lower concentrations had negligible effects on reducing sugar levels. These findings highlight the potential of citric and galacturonic acids as natural acidulants to enhance microbial stability and improve the preservation of tiger nut milk. This study provides a foundation for clean-label, acid-based preservation strategies for plant-based dairy alternatives. Further research is recommended to establish the optimal concentrations for safe and effective application in commercial formulations.