Effect of oxidation of dietary fish lipids on the quality of proteins in diet

The paper reports results of a study on the effect of oxidised fish oil in the diet on the quality of dietary fish proteins. With increased oxidation of oil, digestibility and utilization of the protein registered a decrease. Oxidation of fish oil beyond a stage was found to affect the intake of diet itself and rats lost weight rapidly.

Succession of bacterial genera during iced storage of three species of tropical prawns, Penaeus indicus, Matapenaeus dobsoni and M. affinis

The native bacterial flora of ocean fresh tropical prawns, Penaeus indicus, Metapenaeus dobsoni and M. affinis was more or less similar, mainly consisting of Pseudomonas, Acinetobacter, Moraxella and Arthrobacter. A definite succession of bacterial genera during iced storage was observed in these prawns. As the day of ice storage increased, the proportion of Acinetobacter and Moraxella also increased considerably and constituted 70-78% of the flora at the time of spoilage. Spoilage by Pseudomonas was very not significant in prawns under iced storage.

Preservation of Sardinella longiceps in iced and chilled seawater. Part 1 - Changes during storage with particular reference to bacterial load and nitrogenous compounds

Oil sardines in prime condition were subjected to onboard chilling. Two lots were chilled in CSW (samples C and CI), a third lot was chilled in crushed ice (sample I) and a fourth lot left not iced on deck (Sample AI). Upon landing sample AI was iced and sample CI was removed from the CSW and iced. All the four samples were kept in a chilled room for storage studies. The fish chilled and stored in CSW recorded the least, and the fish subjected to delayed icing, the highest values for all the indices of spoilage namely, free amino nitrogen, trimethylamine (TMA) and total volatile base nitrogen (TVBN). The total psychrophilic bacterial number also showed a similar trend. The organoleptic assessment of the cooked samples revealed C I, CI, AI to be the order of preference throughout the storage. This assessment was found to hold good for the rest of the parameters as well. The CSW held fishes were found to be distinctly superior to the iced ones for the first five days of storage. Such a marked prevalence in quality for five days would suffice for the fish to fetch a premium in the market over other landings of the same fish whether chilled or not chilled. Chilling on board in CSW and icing the same after landings, did not show encouraging results.

Preservation of Indian oil sardine (Sardinella longiceps) in iced and chilled seawater. Part 2 - Changes during storage with particular reference to salt penetration and lipid deterioration during CSW holding

Oil sardines in prime condition were chilled on board. Two lots were chilled in CSW (samples C & CI), one lot ice (sample I) and a fourth lot was left un-iced on deck (sample AI). Sample AI was iced after landing and sample CI was taken out of the chilled seawater and. iced. All the four samples were kept in a chilled room for storage studies. Sample C, chilled and stored in CSW, recorded a gradual gain in weight and an increase in salt content of the muscle. Presence of salt did not seem to cause any excessive protein denaturation. Salt extractability decreased at a gradual rate in all cases. Presence of salt seemed to wield no noticeable influence on lipid hydrolysis and subsequent peroxidation. Results of chemical and sensory evaluations highlight this. Holding sardines in CSW gave a product of excellent quality for the first four to five days of storage. Beyond the fifth day of storage quality deteriorated rapidly and there was no noticeable superiority for this sample (sample C) over the on board iced fish. This was evident in the sensory evaluation as well. However, a storage life of five days in a readily acceptable state is sufficient for the fish to be disposed in the market at a premium sale price over other landings of the same species.

The effect of washing on the quality of minced catfish during frozen storage

The effect of washing minced catfish in water, sodium chloride solution (1%) and ascorbic acid solution (0.1%) in improving the quality and frozen shelf-life has been studied. Washing improved the colour and reduced the non-protein nitrogen contents and extractable nitrogen. Denaturation was more in samples washed in salt and ascorbic acid solutions. Rancidity as measured by PV and organoleptic studies showed significant reduction in washed samples. The frozen storage life was significantly enhanced by washing.

Development and storage characteristics of dehydrated salt mince from low priced fish

The study showed that less initial moisture with high salt content will be the best condition for enhanced storage life of dehydrated salt mince. Between sample I (10% salt per meat weight) and sample II (15% salt per meat weight) the latter was comparatively better in colour, odour and longer shelf-life. At room temperature the dehydrated salt mince has not showed any increase in total bacterial count. It is also found that the storage life of the salt mince can be enhanced to a significant extent by lowering the moisture content to below 10% and increasing the salt content to above 30%. Peroxide value, free fatty acid value, total volatile nitrogen and trimethylamine registered gradual increase during storage at room temperature for all the three samples. Among the three samples, the sample treated with 0.1% citric acid and 0.125% butylated hydroxy anisole was comparatively better in appearance and showed less rancidity as indicated by TBA values, up to a period of 15 weeks and thereafter all the three samples were almost similar in storage characteristics. Hence, the treatment with citric acid and B.H.A. has apparently not much significance in improving shelf-life and quality of salted dehydrated fish mince.

Frozen storage studies of composite fish mince drom dhooma (Sciaenid sp.) and lactarius (Lactarius lactarius)

Fish minces from dhoma and lactarius were mixed in the ratio of 40:60 respectively, and quick frozen along with individual minces at -40°C and stored at -20°C. Shelf life was evaluated by following biochemical, physical and organoleptic changes occurred during storage up to 44 weeks. Rapid decreases were noted in water soluble nitrogen and salt soluble nitrogen fractions during the initial period of 16 weeks. A good correlation was observed between changes in salt-soluble nitrogen and organoleptic evaluation. The minces were in good and acceptable condition up to 32 weeks of storage.

On the ice-storage characteristics of Catla catla and Labeo fimbriatus

The ice-storage characteristics of Catla catla and Labeo fimbriatus are reported. Muscle pH, moisture, total volatile nitrogen, alpha amino nitrogen and peroxide value and also the changes in total bacterial count are studied. C. catla and L. fimbriatus both could be stored in ice for 18 days.

High temperature processing of fish sausage 3. - Studies on some of the storage characteristics

The proximate composition of the high temperature processed fish sausage was found to be 14.56% protein, 4.65% fat, 69.14% moisture, 2.12% ash and 8.12% carbohydrate. The quality of the product during storage was assessed on the basis of the changes observed in the physical, chemical and microbiological parameters. The results of the different tests such as pH, volatile base nitrogen (VBN), trimethyl amine nitrogen (TMA-N) and jelly strength are summarized and discussed. The total bacterial load increased gradually during storage but was not proportional to the initial load.

Studies on iced storage of common murrel (Channa striatus)

The iced storage characteristics of common murrel (Channa striatus) have been studied. The non-protein nitrogen and alpha amino nitrogen in the muscle of the fish decreased during iced storage and the total volatile base nitrogen at the end of iced storage was not high even though the fish became unacceptable during the period. There was steep decrease in total bacterial count during initial storages of storage and then increased steadily on further storage. The fish remained in acceptable condition for 8 to 9 days in ice.

Effect of chilled sea water storage of oil sardine (Sardinella longiceps) on quality changes during frozen storage

The shelf-life of frozen oil sardine (Sardinella longiceps) can be improved by preserving the fish immediately after catch in chilled sea water before freezing. Delayed icing caused considerable deterioration in quality and reduced frozen shelf-life. Oil sardine preserved in chilled sea water were found to be suitable for freezing up to 5 days whereas iced samples could be frozen only up to 2 days.

Studies on frozen storage of cuttle fish fillets

The freezing and cold storage characteristics of cuttle fish fillets have been studied. The yield of fillets from cuttle fish was about 35% and the fillet had an average moisture content of 76.85% and fat 0.82% During storage at -20 ± 1°C for 16 months the salt soluble nitrogen of the fillets decreased from 85.1to35.36%, the non-protein nitrogen from 24.61 to 20.84% and alpha amino nitrogen from 252 to 140mg/100g. Initially the fillets were white in colour, showed signs of desiccation by 4 months storage which increased on further storage and the fillets finally became dull white with yellow discolouration inside. The firm and chewy texture of the cooked fillets changed to rubbery even though the product was slightly sweet at the end of that storage period of 16 months.

Studies on freezing and storage of Psenopsis cyanea

The freezing and storage characteristics of Psenopsis cyanea caught on board FORV Sagar Sampada from a depth of 350 m off Cochin are reported. The fat content of the fish was high (15.58% on the weight of whole fish) and the meat was white in colour. Peroxide value, free fatty acids and thiobarbituric acid values increased during frozen storage and organoleptically the fish was acceptable up to 32 weeks at -22 ± 1°C.

Effect of liquid nitrogen freezing and subsequent storage on survival of Staphylococcus aureus and Streptococcus pyogenes in treated prawn meat

Prawn meat treated with Streptococcus pyogenes B-49-2 culture and Staphylococcus aureus ATCC-12598 culture were frozen in conventional plate freezer at -40°C and by spray type liquid nitrogen freezer. The frozen products were stored at -18°C. Streptococcus pyogenes B-49-2 showed low sensitivity to cold injury during freezing and frozen storage. Staphylococcus aureus ATCC-12598 survived during the entire storage period of 240 days. Total bacterial count of untreated prawn meat was found to be always lesser in liquid nitrogen frozen products than that in plate frozen products.

Effect of pre-processing iced storage on deteriorative changes in lipids of silver pomfrets stored at -18°C

Silver pomfret (Pampus argenteus) was frozen in the fresh condition as well as after holding in ice for one, two and four days. Evaluation of changes in the quality of these samples during storage at -18°C has shown that shelf-life decreased sharply if the pre-freezing iced storage was more than one day. The shelf-life of one day iced, two day iced and four day iced frozen samples were 32, 20 and 16 weeks respectively. No correlation was observed between the peroxide value and the organoleptic detection of rancid flavour. Levels of free fatty acids were more in the samples frozen after storage in ice for one day than in all the other samples.