Orange Juice Preservation

The chemical properties of chemically preserved orange juice are presented in Table 1. The pH of the examined orange juices ranged from 3.30 to 3.66. The pH decreased with increasing week of storage indicating acidity in orange juices. The use of sodium benzoate, sodium metabisulphite and potassium sorbate as preservatives significantly influence the pH of orange juice. The pH of samples was stable throughout the first and second week of storage. However, on the third week of storage, the pH of orange juice preserved using sodium metabisulphite and the control sample decreased and were significantly different to other samples (P ≥ 0.05).

The pH of orange juice preserved with sodium benzoate (SB), potassium sorbate (PS) and combined selected

The total soluble solids of samples was constant throughout the three weeks of storage except in SM and UNT. Total soluble solids of samples SM and UNT reduced with storage especially in week three of storage. Total soluble solids was lowest in the control juice (9.20 oBrix) while the total soluble solids was highest in SB (9.80 oBrix) at third week of storage. This findings showed that the combine use of the selected preservatives used in this study i.e Sodium metabisulphite and Potassium sorbate could inhibit the fermentation activities of colonizing microorganisms in fruit juice. Has earlier reported by Leahu et al., (2013), the total soluble solids of juice samples remains almost constant in the initial weeks of storage. The stability in the total soluble solids of orange juice within the first two weeks of storage observed in this study corroborates the findings of Leahu et al. (2013) that total solids of juice made from orange, kiwi and apple remains almost constant in the initial weeks of storage. Also, this finding supports the work of Rivas et al. (2006) who reported a decrease in total soluble solids of juice stored for seven weeks. However, the slight disparity between the values reported in this study and that of Rivas et al. (2006) might be due to different method of juice extraction, type of fruit, degree of ripeness and geographical location of orange fruit used in the

2. The vitamin C content of the chemically preserved orange juice ranged from 150.90 – 238.60 mg/100 g and decreased with increase in weeks of storage. On the third week of storage, the vitamin C content was highest in SM (164.90 mg/100 g) but not significantly different to AP (161.40 mg/100 g) at P≥0.05. The vitamin C content was lowest in the control sample. Ascorbic acid is sensitive to oxygen, light and heat. The reduction observed in the vitamin C content of samples with storage might be due to the degradation ability of ascorbic acid to dehydroascorbic acid in orange juice when exposed to heat, light or oxygen. However, the vitamin C contents of the samples were within the recommended dietary allowance for vitamin C in juices (40 mg/100 g). This finding is in conformity with the report of Shahnawaz et al. (2013) on the use of sodium benzoate as chemical preservative to improve the shelf life of orange juice. The analysis of variance indicated that the effect of various preservatives on Vitamin-C in orange juice was not statistically significant (P≥0.05) especially at the second and third week of