Nutritional Composition, Anti-oxidant Potential and Shelf Stability of Mint Flavored Passion Fruit Juice

Abstract

Previously, mint has been used to flavor several foods but no emphasis was put on flavoring certain juices such as passion fruit juice. Thus, its effect on the properties of passion fruit juice were unknown. Much as different extracts of mint are used to improve the properties of foods, there is scanty information on use of mint hydrosol, a by-product of mint essential oil production. This research evaluated mint as a flavorant in passion fruit juice. Juice formulations containing 4-16% of either mint extract (n=4) or hydrosol (n=4) were used. The effect of mint on the nutritional composition, antioxidant potential, sensory acceptability (n=25 panelists), and shelf stability of the fruit juice were monitored at 0, 35, 70, and 140 days of storage at room temperature (24±4°C). Addition of mint extract or hydrosol significantly (p<0.05) influenced the sensory acceptability of passion fruit juice. Acceptability scores reduced with increase in mint extract or hydrosol concentration. Among the mint flavored juices, that with 4% extract or hydrosol was the most accepted and was quite similar to the control. This was followed by juice flavored with 8% extract or hydrosol while that with 16% was unacceptable. Nutrient composition of the juice in terms of vitamin C, beta-carotene and total antioxidants significantly increased with increase in mint extract concentration in the juice (p<0.05). Of the three acceptable juice formulations, that containing 8% mint extract had the highest amount of vitamin C (7.81±0.00 mg/100ml), beta carotene (104.81±0.43 μg/100ml), and total antioxidants (303.04±0.34 mg ascorbic acid equivalent /100 ml). The vitamin C and beta carotene of samples containing hydrosol was not significantly different from plain passion fruit juice (p>0.05). The juice samples were stable throughout the storage time. Passion fruit can, therefore, be flavored with up to 4% mint extract or hydrosol without negatively affecting its sensory properties whilst improving its antioxidant potential.