Effects of processing on nutrient composition, shelf-life and protein-bioavailability of anchovies fish from Indian Ocean (Stolephorus heterolobus)

Masters Thesis

This study assessed changes in chemical components of the sun dried and hot smoked anchovies processed by traditional and improved methods. Except for the protein-bioavailability analysis which took place once during the fourth week, the samples of fish were assessed weekly. Nutrient composition, shelf-life and protein-bioavailability of processed anchovies were assessed using changes in proximate composition and specific minerals, biochemical indices and protein-digestibility, respectively. The pH levels decreased and TVB-N increased with the number of weeks. These situations implied that spoilage of anchovies occurred gradually. Changes in moisture content, crude protein and calcium indicated significant differences (p ≤ 0.05), in terms of processing methods (hot-smoking against sun-drying). The packaging aspects were not significantly different for all parameters (p > 0.05). In categories of processing methods (traditional versus improved methods), the mean values of crude protein, crude fat and zinc were significantly different (p ≤ 0.05). The mean protein-digestibility values (73.8%) for each pair of processing, packaging and categories of processing aspects were not significantly different from each other (p > 0.05). The implication is that the availability of protein by the healthy human body depends on increase in nutrient-density. It was concluded that the protein-density of fish products processed by improved methods was higher than that of traditional methods. Based on moisture contents of anchovies processed by improved methods, their shelf-life could be extended for more than a month. It was recommended that moisture content less than 10% should be maintained to reduce microbial contamination. The use of hot smoking should be encouraged in order to dry the fish throughout the year.