Abstract:
Watermelon, pineapple and pawpaw are tropical fruits which tend to have short shelf-life due to the climatic conditions of Nigeria. Processing them into smoothies (blended fruit in the ratio of water) will reduce their amount of postharvest loss and create availability of natural fruit smoothies in the market or at home for intake. Smoothies were produced from the blends of pineapple, watermelon and banana, treated with garlic and ginger, bottled, pasteurized and stored for 8 days to obtain a total of 12 samples and 3 controls (prior to storage). Chemical parameters such as vitamin C, total phenol, total sugar, moisture and crude fibre contents, titratable acidity, pH, minerals (calcium, sodium, potassium and magnesium), microbiological and sensory qualities were monitored daily/weekly throughout the storage periods. Results showed the type of spices as the most significant factor (p = 0.05) with respect to variables considered. There was a decline in vitamin C, titratable acidity and pH as storage time advanced. Total and reducing sugars and oBrix increased with storage while other chemical parameters did not change significantly. Garlic and ginger extracts enhanced microbial stability and contributed to better sensory acceptability of the samples. Smoothies enriched with garlic had comparatively higher TPC, crude fibre, pH, vitamin C, sodium and its ratios with potassium and magnesium within the 0 – 8 days of storage, total and reducing sugars on the 8 day of storage. Conversely, smoothies enriched with ginger were high in acidity, sensorial scores, magnesium and potassium within the first 0 - 6 days of storage and oBrix on the 8 day. The results revealed that only the blends with garlic and ginger as preservatives in the watermelon: pineapple: pawpaw blend gave an improved composition in terms of the physicochemical properties determined and extended the shelf life of the smoothie for one week. Garlic and ginger are potent natural preservatives with additional nutritional benefits that could replace synthetic additives.
