Selective release of fatty acids during lipid hydrolysis in frozen-stored milk fish (Chanos chanos)

Lipid hydrolysis and the nature of fatty acids lost as a result of lipid hydrolysis in milk fish (Chanos chanos) during frozen storage at -20°C is discussed in this paper. There was a preferential loss of saturated acids during the first three weeks of storage. This was followed by loss of polyunsaturated acids during the next seven weeks. Sharp decrease in the levels of monounsaturated acids was observed from the 10th week of frozen storage. These observations are due to the preferential hydrolysis of phospholipids with relatively high proportion of saturated acids during the first three weeks, followed by the hydrolysis of phospholipids with high proportions of polyunsaturated fatty acids from the 3rd to the 10th week, and finally, predominant hydrolysis of neutral lipids from the 10th week onwards. Storage of fish in the ice prior to freezing was found to accelerate lipid hydrolysis, especially that of neutral lipids, during frozen storage

Lipid hydrolysis in mackerel (Rastrelliger kanagurta) during frozen storage

The hydrolytic changes in the lipids of mackerel (Rastrelliger kanagurta) during storage at -l8°C were studied with a view to understand the factors involved in the formation of free fatty acids. Only the phosphorylated fraction did undergo hydrolysis at an appreciable rate. It was found that the free fatty acid production was mainly associated with the phospholipid hydrolysis. As regards the triglycerides and unsaponifiable matter, there was no significant change in levels during frozen storage

Lipid breakdown in oil sardine (Sardinella longiceps) during frozen storage

The problem of hydrolysis of lipids and consequent accumulation of free fatty acids and development of rancidity due to oxidation of the lipids are major problems in frozen storage of oil sardine (Sardinella longiceps). The course of the phospholipid breakdown, production of free fatty acids and the changes taking place in the major unsaturated fatty acids during frozen storage are described in this paper. The rate of free fatty acid production is faster in the fish, with the higher fat content. Unlike in lean fish, the neutral lipids are found to contribute substantially to the free fatty acid production. The fatty acids most affected during storage are C sub(20:5) and C sub(22:6). The polyene indices were found to decrease during storage. These effects are more pronounced in the fish with the higher fat content

Studies on lantern fish (Benthosema pterotum) 1. Biochemical and microbiological investigation

Lantern-fish, an under-utilised fish is present in abundance, all the year round in tropical and sub-tropical waters. Biochemical and microbiological studies carried out on lantern fish, caught from the Gulfs of Oman and Aden are reported in this paper

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Not AvailableMonthly variation in the fatty aid composition of muscle and skin lipids of oil sardine (sardinella longiceps), for a period of two years ar presented. Data shows wide variations in the proportions of the various acids in these lipids during different seasons. Total saturated acids in muscle lipid varied from33% to 42% with an average of 38%. Toatal monounsturated acids averaged 22.2%,lowest value being 14% and highest 30.1%. Proportions of total polyunsturated acids ranged between 28% and 52.5% (average 40.1%). Similar variations were observed in the case of all major component acids. The pattern was similar in skin lipids had a slightly higher level (by about 3%) of total monounsaturated acids and correspondingly lower proportions of polyunsaturated acids.Not Availabl

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Not AvailableOne of the uses of thermally stable dispersions of fish myofibrillar proteins is as edible film. A modified method of preparation of thermostable dispersions was developed which involves acidification of meat water homogenate.The dispersions were cast in glass trays and dried in an oven at 50 degree C. Dried dispersions yielded light yellow translucent films with good flexibility. The films become brittle if dried further or stored at low humidity. Heating the dispersions prior to casting excluded air bubbles and thus improved the quality of films.Not Availabl

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Not AvailablePesticides and polychlorinated biphenyls (PCBs) are ubiquitous toxic constituents due to their bioaccumulation and specific physicochemical properties. These compounds accumulate in the biota of all levels and the residues are present in all environmental compartments from all geographical areas. Elevated pollutant concentrations are generally the consequence of effluent discharge and agricultural and industrial runoffs. Although majority of these compounds enter the environment through anthropogenic activitiesa, marine algae and invertebrates and natural processes such as forest fire also contribute their share. The development of global quality assurance criteria and the general awareness of the consumer for quality of the food forced a new approach in the quality aspects of food commodities and seafood is no exception to this. In the light of strigent safety measures with respect to seafood imposed by EU and other developed countries, the understanding on pesticides and PCBs assumes significance. Though present in extremely low concentrations, they definitely pose a chronic health hazard. However, the major problem, associated with these chemicals was their method of detection . The advancement of gas chromatographic and HPLC systems has made it possible to quantify these toxic chemicals for the benefit of the mankind. This paper provides an insight into the general aspects of pesticides and PCBs besides highlighting the health hazards, bioaccumulation in sediments, fish and other aquatic biota and their relevance to the quality assurance system of seafood.Not Availabl

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Not AvailableCasein or fish proteins (from Nemipterus japonicus), as the main source of protein and groundnut oil or sardine as the main source of fat, were used in four different combinations in diets of four groups of 5 week-old albino rats to see their effect on the cholesterol levels in the serum, liver and heart of the animals. Casein groundnut oil group (control)had the highest level of serum cholesterol and casein-fish oil group, the lowest. Fish protein-groundnut oil-fed animals also showed a significantly lower level of serum cholesterol, suggesting a hypocholesterolemic effect in the case of fish protein also. However, in the case of fish protein-fish oil group, the lowering of cholesterol was not as pronounced as would be expected of a combined hypocholesterolemic effect of fish oil and fish protein. The pattern of increase in liver cholesterol levels. Significance of these finding are discussed.Not Availabl

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Not AvailableEffect of a polyunsaturated fatty acid (PUFA) concentrate containing about 80 percentage free acids at a level of 1 percentage of the diet, on the fatty acid profile of the lipids of liver and heart of rats fed on it for a period of three months was investigated. Law levels of dietary PUFA influence fatty acid composition of the lipids in liver and heart. The pattern of changes was different in the two organs, indicating tissue specificity to n-3 PUFA.Not Availabl

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Not AvailableIn the present study, the administration of peroxidised PUFA was found to aggravate the isoproterenol-induced myocardial infraction in rats, which was evident from the increased level protein and enhanced the release of marker enzymes in the serum of rats given PUFA and isoproterenol. It was also observed that oxidized PUFA in the diet resulted in higher levels of peroxidation and lower levels of antiperoxidative enzymes.Not Availabl