Changes in quality attributes of mixed roselle, water melon and grape juice using Aframomum danielli as a preservative

Abstract

Roselle, water melon and grape juice are excellent sources of vitamin C. The shelf life of most fresh fruit juices stored under room temperature is very short. The use of Aframomum danielli (A. danielli) as a preservative is not known. Roselle juices processed at 1:1 and 1:2 with or without A. danielli of 15% concentration were stored for two weeks at room temperature and evaluated for chemical properties and sensory attributes. Sensory evaluation of the juices were done by a 10 membered panel randomly selected from male and female adults. At zero day of storage, roselle grape juice of 1:2 ratio with A. danielli was significantly higher in total solids (0.637%) and ash content (0.072%). The vitamin C content of roselle-water melon juice of 1:2 ratio with A. danielli was higher at p<0.01. At one week of storage, there was a decrease in ash, specific gravity and vitamin C content of the juice. Roselle grape juice of 1:2 ratio with A. danielli was higher in ash (0.0675%). The vitamin C content of roselle-water melon of ratio 1:2 with A. danielli (17.125%) was significantly higher. At two weeks of storage, there was a drop in ash, specific gravity and vitamin C content of the juices. Higher sensory scores were given to roselle based sample with A. danielli at 0, one and two weeks of storage. Roselle grape juice of ratio 1:2 with A. danielli was rated high in general acceptability at zero and one week of storage. In summary roselle grape juice of ratio 1:2 with A. danielli had acceptable nutrient and sensory qualities at one week of storage. Beyond one week, the preservative potential of Aframomum danielli at 15% concentration was low.