Effect of Storage Temperature on the Nutritional Compositions of Lactic Acid Bacteria Fermented Spicy Tigernut- Milk Drink

Abstract

The fundamental benefit for consuming edible products is based on its nutritional compositions. Several factors affect the nutritional composition of diverse edible products. This study was carried out between August-October, 2016 at Federal Institute of Industrial Research Oshodi (FIIRO), Lagos. Lactic acid bacteria (LAB) were isolated from ‘ogi’ using MRS agar and characterized using API 50 CHL test kit. Tigernut tubers were used to prepare tigernut-milk which was fermented by mixed culture of LAB for 12 hr at 45ºC. The LAB fermented tigernut-milk drink was separately spiced with 3 % (w/v) ginger, 5 % (w/v) ginger, 3 % (w/v) garlic and 5 % (w/v) garlic. The final products were stored at 28±2ºC and 4±2ºC for 12 wks and their nutritional composition was monitored at 4 wk interval using conventional and rapid test methods. Results obtained revealed there was reduction in carbohydrate, moisture and lipid content during storage of the tigernut-milk preparations. Importantly, the protein content in the tigernut-milk preparations increased during storage at both conditions except in the 5 % (w/v) ginger spiced tigernut-milk drink which ranged from (6.48-11.24 %) and (6.07-10.91 %) during ambient and refrigeration temperature storage, respectively. There was also reduction in Ca, K, Mg and Zn content in the tigernut-milk drink preparations during storage at 28±2ºC and 4±2ºC. Generally, the mineral content of spiced tigernut-milk drink preparations stored at 4±2ºC was higher than similar drink stored at 28±2ºC with very few exceptions. Remarkably, the high potassium content in 3 % (w/v) ginger and 3 % (w/v) garlic spiced tigernut-milk could be more effective in prevention of hypertension and artherosclerosis compared with 5 % (w/v) ginger spiced and 5 % (w/v) garlic spiced tigernut-milk drink. Therefore, this study projects tigernut-milk drink fermented by LAB and separately spiced with 3 % (w/v) ginger and 3 % (w/v) garlic as a nutritious drink to be preferably stored at refrigeration temperature.