ABSTRACT

This study investigated the production and evaluation ofthe shelfstability ofbottled and sterilized Tigernut milk. Two varieties of tigernut (brown and yellow) were used. Tigemut milk was produced using three processing methods (boiling, malting and soaking). The milk was bottled, capped and sterilized then stored at room temperature for shelf-life studies. The indices evaluated were proximate, physicochemical (pH, total titratable acids and total solids), phytochemicals, minerals, vitamins, microbial quality and sensory characteristics. The proximate results obtained showed that the yellow tigernut tuber had higher moisture content (39.16%) than the brown variety (9.17%) while the brown variety recorded higher values in protein, ash, fiber and carbohydrate. In addition, the mineral composition showed that tigemut tubers are rich in essential minerals and some vitamins. The tigernut milk had high moisture content (89.19% - 93.19%) for both varieties and preprocessing methods used. The malted sample recorded the highest ash content (0.280%). The result recorded (0.00%) for crude fiber as it was lost during extraction ofmilk. The result obtained showed that processing and sterilization had significant effect on the phytochemical content oftigernut milk except flavonoid for the boiled yellow sample which was not significantly different (p >0.05). The physicochemical result showed a pH range of (5.05-6.90) which indicate that tigernut milk is a low acid food. The physicochemical properties recorded showed that tigernut milk is a low acid food, the pH values varied significantly (p < 0.05), and as pH decreased the total titratable solids increased. Malted brown samples recorded the least pH value of (5.05). The vitamin content decreased after sterilization. However, Malting enhanced the retention of vitamin Bi.Be and C during storage. As storage progressed, the vitamin Bi was lost from the fourth month to the sixth month. The initial bacterial and fungal count recorded for the fresh tigernut milk was high but decreased after sterilization. There was no viable bacterial and fungal growth on the milk after sterilization. The microbial quality over the storage period decreased significantly, there were no fungal counts by the fourth month and no microbial load was recorded at sixth month. The result of the sensory analysis varied significantly within the samples and during storage based on individual perception; there were significant difference (P< 0.05) in taste for the malted samples as storage progressed. The result obtained in this study indicates that the processing methods and sterilization enhanced the quality of tigernut milk. The study highlighted the possibility of processing tigernut tubers into shelf-stable milk that can be stored for an extended period.