ABSTRACT

The fruit of Averrhoa carambola L, also known as Starfruit is an attractive fruit of the Oxalidaceae family. As most of the carambola fruits are consumed fresh, very few are processed around the world. The fruit is rare and underutilized in Nigeria. In this work, physical and nutritional composition of the starfruit were studied and evaluated at different maturity stages. The physical properties like length, diameter, fresh weight, dry weight, pH, colour, texture, flavor and sugar content (SC) were characterized. The length of the fruit increased from 7.13cm (unripe) to 10.17cm (Soft fruit). The diameter also increased with maturity. There was a substantial increase with maturity in the fresh and dried weight of the fruits. The fruit was found to be more acidic in the unripe (pH 2.34) and less acidic in the Soft ripe (4.82) fruit. Within 3- 5days of storage, the colour, texture and flavor of the fruits changed progressively with ripening as with other tropical fruits. The sugar content of the fruits ranged from I .064% in young fruit to 2.303% in soft ripe fruit. The fruits were characterized for chemical properties like oxalic acid, which is significantly higher 1.0067mg/100g in the firm ripe fruit than in the soft ripe fruit (0.760 mg/l0og), and Total Polyphenols which increased significantly as the fruit matured (27,65g/GAE/l 00g fresh fruit) and (3 1 .27g/GAE/lOOg fresh fruit) in the firm and soft ripe fruits respectively. The fruit had a characteristic soft, fragile and thin skin, relatively few seeds and high moisture content (89.65% to 92.67%) which made processing into a fruit juice fairly simple and easy. The crude fibre was substantially high (2.269 to 4.016%). The Carbohydrates, ash, fat and crude protein contents were found to be relatively low. The fruit was made into Juice and Jelly which was Physico-chemically, and statistically evaluated to determine the general composition and suitability of the fruit for further processing. The Juice and Jelly were analyzed to determine total solids, specific gravity, sugar content, titratable acidity and Vitamin C. The titratable acidity of the Juice corresponded with the pH of the fruit (2.929 and 3.771goxa1ic acid/lO0gfresh fruit juice) for firm and soft ripe fruits respectively. The total solids, specific gravity and sugar content were low and increased significantly with ripening. Vitamin C content was substantially high (28.61 to 38.24mg/bOg). The Vitamin C content of the Starfruit juice was significantly different from that of the commercial fruit juice at (P<0.05). The Physico-chemical analysis of the Jelly also showed little or no significant differences with the commercial mixed fruit Jam, particularly in sugar content (60.000band 67.500a mg/bOg), Vitamin C (12.300band 18.6 isa mg/bOg). Though the sensory evaluation rated the carambola juice and jelly generally acceptable, significant different exist between the carambola juice, jelly and the commercial juice and mixed fruit jam particularly in flavor and color. > The Physico-chemical analysis of the Jelly also showed little or no significant differences with the commercial mixed fruit Jam, particularly in sugar content (60.000band 67.500a mg/bOg), Vitamin C (12.300band 18.6 isa mg/bOg). Though the sensory evaluation rated the carambola juice and jelly generally acceptable, significant different exist between the carambola juice, jelly and the commercial juice and mixed fruit jam particularly in flavor and color