Sensory and Microbiological Quality Attributes of Laboratory Produced Tigernut Milk during Ambient Storage

Abstract

Tigernut milk produced from the seed of tigernut (Cyperus esculentus L.) was pasteurized and treated with or without the addition of chemical preservatives (singly- 0.08% sodium benzoate, 0.02% sodium azide or in combination- 0.04% sodium benzoate + 0.01% sodium azide). These were evaluated for its microbiological and sensory quality characteristics during 12 days storage period (28±2°C). The results obtained show that the total viable counts (cfu/ml) of the tigernut milk pasteurized and treated with sodium azide was lower on days one (7.6×101), seven (1.3×101) and twelve (3.1×101) and were significantly different (p<0.05) from the total viable counts of the rest products; which ranged from 1.33×104 and above at end of the 12 days study period. Similarly, a low fungal count was observed in the tigernut milk pasteurized and treated with 0.02% sodium azide which was generally low throughout the storage period and significantly differed (p<0.05) from the other products. The results of this study has shown that the tigernut milk pasteurized and treated with sodium azide was generally preferred in all the sensory quality attributes (colour, aroma, taste and overall quality) and was significantly different (p<0.05) from the rest products. This study therefore shows that the shelf life of tigernut milk could be extended up to 12 days using combination of pasteurization and incorporation of 0.02% sodium azide.