Chemoprotective Potential of Selected Preservatives against Spoilage Microorganisms Associated with Stored Zobo and Their Resultant Effects on the Juice’s pH and Ascorbic Acid

Samples of extracts from Hibiscus sabdariffa calyxes were stored with different preservatives (sodium benzoate, sodium metabisulphite, boric acid and citric acid) for eight weeks and studied forthnightly for change in certain parameters. A sample (control) was also stored without preservative for the same period. The research was carried out to study the possible effect(s) of these chemical preservatives on the pH, ascorbic acid and microbial growth of the juice. Up to 4 weeks of storage, all the samples were not statistically different at 95% confidence level except sample preserved with sodium benzoate with respect to vitamin C. In the same manner, with exception of samples without preservative and the one stored with sodium metabisulphite, other samples were not significantly different at P<0.05 with respect to pH. Generally, the findings revealed an increase in acidity (decrease in pH), loss of vitamin C and increase in microbial population as the duration of storage was elongated in all the samples but much more explicit in the sample without preservative. Likewise, the rate of change of pH and percentage loss of vitamin C with respect to storage time in the sample without preservative increased tremendously compared to other samples. The results bare that the use of preservatives prohibited rapid loss of nutrients and inhibited the microorganisms that cause spoilage on storage of this juice of hidden health benefits. The use of preservatives to prolong the shelf life of this juice is therefore advocated so as to make it more available round the year.