Effects of Drying on the Biochemical Composition of <i>Atherina boyeri</i> from the Tunisian Coast

Abstract

The effects of solar and experimental drying on the protein concentration and total fatty acid (TFA) content of the muscles of Atherina boyeri (sand smelt) were studied. The percentage of protein was 18.3% for fresh fish and 14.2% for sun-dried fish, while TFA content was 4.9 g/100g and 0.5 g/100g. After the drying experiment, the percentage of protein was 23% and the fatty acid (FA) content was 2.8 g/100g. The results show that natural or experimental drying favors saturated fatty acids. The n-3 polyunsaturated fatty acids (PUFAs) are less sensitive to heat than the n-6 PU-FAs. From a nutritional point of view, it seems that the drying conditions, where parameters are T = 50˚C, moisture = 30% and air speed = 2 m/s, would be the most beneficial for the preservation of sand smelt.

Effect of processing methods on nutritional and physico-chemical composition of fish: a review

“…Fish is a rich source of chemical composition such as proteins, fat (poly-unsaturated fatty acids), vitamin (including, vitamin A, vitamin B2, vitamin B6 and others), minerals (iron, calcium, iodine, potassium and other minerals), and carbohydrates. 2,9 In many part of the world people use fish as the main component in their diet, as a good source of nutrition. 5,11 Fish constitute more protein source than other animals protein source.…”

“…Fish can be preserved using solar drying, which focused to reduce the water content; whereby activities of microorganisms will be reduced or stopped. 5 According to Smida et al, 9 drying has a great negative effect on protein content at a lower drying speed of one meter per second. Solar drying also affects poly unsaturated fatty acids particularly omega-6 fatty acids.…”

“…Exposure of fish for long period of time to sun light can oxidize the lipids, which can reduce nutritional quality and increase health risks of consumers. 9 The factors that influence quality of freeze dried fish during drying are chemical; browning reactions, lipid oxidation, color change, physical; rehydration, solubility, texture, aroma loss and Nutrition; vitamin loss, protein loss and microbial survival.…”

“…Another effect is the destruction of cell membrane and the aggregation of sarcoplasmic protein. 14 Smida et al,9 reported in their findings that, heating affects the liquid holding capacity of frozen fish, whereby resulted in protein deterioration at higher temperature, leading to dehydration of the muscle through disruption of cell structures and becomes very tough texture, difficult to eat.…”

“…4 In addition, preservation and processing can assure availability of fish in all year round. 9,10 The bio-chemical composition of fish is the vital aspect in fish processing, because which influences both the quality and technological characteristics of it. 5 Different processing methods of fish have different effect on their chemical, physical and nutritional compositions.…”