EFFECT OF CHITOSAN AND SODIUM CHLORIDE APPLICATION ON THE STORAGE STABILITY OF COOKED WALNUT SEEDS

Abstract

Samples of cooked walnut (Tetracarpidium conophorum) seeds were subjected to proximate and microbiological analysis. The nuts were divided into eight groups and subjected to various preservative hurdles for 20 days. Proximate analysis showed that the nut had moisture, lipid, protein, ash, carbohydrate and crude fibre content of 46.70±1.50, 6.00±0.05, 53.53±2.31, 2.96±0.06, 32.79±1.50 and 4.72±0.15 respectively. Microbiological analysis showed the presence of bacteria such as Bacillus subtilis, Staphylococcus aureus, Leuconostoc spp, Pseudomonas spp and Escherichia coli. Fungi isolates include Saccharomyces cerevisiae, Candida spp, Aspergillus niger and Aspergillus flavus. Among the bacteria, Staphylococcus aureus, and Leuconostoc spp had the highest percentage (100%) occurrence. Saccharomyces cerevisiae was predominant (80%) among the fungi. Sample preserved with sodium chloride and stored at 4±10C had the least microbial count (3.00log10cfu/g) compared to others. The best preservative hurdle in the study was the application of 1000?g/g of chitosan for 2 weeks. Chitosan preserved walnut not only remained fresh but had chemical composition like the freshly cooked sample. The results show that Tetracarpidium conophorum is a good source of protein for man and animals as it contains nutrients that are necessary for maintenance of body cells and tissues. Successful shelf-life extension can be achieved using crab chitosan