Effect of Calcium Carbide as a Ripening Agent on the Nutritional Composition and Ripening Time of Banana Pulp

Abstract— This study was carried out to examine the effect of calcium carbide as a fruit ripening agent on sensory properties, nutritive properties, metal composition and some antioxidant enzymes of banana pulp. Bananas were separated into 4 groups made up four (4) banana fingers each of approximately the same size. Calcium carbide was administered at two different concentrations (4g/kg) for Group 2 and (8g/kg) for Group 3. Group 1 was the unripe banana while Group 4 was a naturally ripened banana (Control). The results obtained revealed that calcium carbide is a very good ripening agent with a ripening time of 3days (72 hours) and 2days (48 hours) for Group 2 and Group 3 respectively. The results also showed that calcium carbide at (4g/kg) and (8g/kg) did not affect the sensory properties as there was no significant (p≥0.05) variation. There was a significant (p≤0.05) difference in the proximate values. Moisture contents of the bananas ranged from 69.40±1.54 GRP 1 to 77.78±0.80 in GRP 4, while crude protein ranged from 1.27 ± 0.01 in GRP 2 to 2.25±0.13 in GRP 4. Ash content ranged from 1.59±0.09 to 2.78±0.13 with GRP 1 having the significant (p≤0.05) highest value. Total carbohydrate content ranged from 15.23±0.92 in GRP 4 to 24.39±3.04 in GRP 2. The result on mineral composition showed that there was a significant (p≤0.05) decrease in Pb content during ripening. GRP 4 banana had the lowest Pb value at 0.02 ± 0.01, while GRP 1 had the highest values at 0.07 ± 0.01. The highest contents of Zn and Mg at 6.08 ± 0.08 and 9.12 ± 0.37 respectively were recorded in GRP 4. There were significant (p ≤ 0.05) difference in the Mn, Ca and Cd contents (2.42 ± 0.12, 2.24 ± 0.20 and 1.46 ± 0.05 respectively) in the banana treated with 8 g/kg CaC2 (GRP 3) when compared with the rest of the groups. Cu content ranged from 0.38 ± 0.01 in GRP 4 to 1.64 ± 0.09 in GRP 1. From the result of antioxidant enzyme activities, calcium carbide affected all the antioxidant enzymes activities (Catalase, peroxidase and Ascorbate peroxidase) at 4g/kg and 8g/kg as their concentrations significantly (P≤0.05) decreased the amount of the enzymes, when compared with the naturally ripened banana. The peroxidase activity was significantly (p≤0.05) higher in GRP 4 at 3.42 ± 0.05 U/mL than the rest of the groups. The ascorbate peroxidase activity was also highest in GRP 4 at 33.79 ± 2.15 U/mL. The catalase activity ranged from 0.38 ± 0.24 U/mL in GRP 3 to 0.68 ± 0.15 U/mL GRP 4. These results showed that even though calcium carbide may have fruit ripening ability, it also causes reduction in the fruit nutrients and antioxidant enzyme activities.