Recent developments in fish processing and preservation

A review of the literature on fish processing will reveal that most of the important developments have taken place during the last twenty years. Sustained work by teams of scientists in different parts of the world, has not only contributed much to our knowledge of the chemistry and technology of fish but also resulted in revolutionary changes in the methods of preservation and processing of fishery products.

A survey of the quality of salt cured fish produced in the Kanyakumari Disrict [i.e. District], Madras State

A survey of the quality of salt cured fish in Kanyakumari District, Madras State was done during the years 1963 and 1964 to obtain necessary basic information to formulate quality standards for these products which are gaining importance in the export trade. 155 trade samples of sun-dried, dry-salted, wet-cured and pit-cured fishery products were examined for their chemical quality and organoleptic characteristics. 26.5% of the sun-dried products, 25% of the wet cured fish, 55.21% of the dried salted products and none of the pit cured samples were found to be good in quality. The sun dried products were generally found to have heavy admixture of sand and were inadequately dried. The chief defects in the salt cured fish products were found to be the use of spoiled fish, imperfect cleaning and washing, use of impure salt, inadequate salting, curing and drying, and unhygienic conditions in all stages. Quality standards must be formulated for each variety of salt cured fish product and adequate measures taken to rectify the defects and enforce the quality standards.

The bacterial flora and their possible association with spoilage in a variety of fresh-water fish: Cyprinus carpio. var. communis

The bacteria from a variety of fresh-water fish, Cyprinus carpio. var. communis, showed the presence of micrococci, Gram positive and Gram negative rods. These have been characterized as far as was possible. Of thirty-eight strains of bacteria used, only six strains were considered as causing spoilage of fish flesh in experiments where flesh was incubated with individual cultures of the bacteria. These six strains had been found on the surface and/or intestine of the fish and support the suggestions that, after death, invasion of flesh by bacteria from the surface and intestine could be the cause of bacterial spoilage of fish.

Measurement of moisture in dry cured fish by infrared irradiation

Heating conditions have been standardised for measurement of moisture in dry cured fish using infrared irradiation source of 150w. Results obtained are comparable to those obtained from standard air oven method (drying to a constant weight at l02°c), the mean deviation being less than two units. The method works equally well for fresh fish muscle.

Utilisation of trash fish. Pt. 1. Preparation of fish flake

The paper deals with the investigations carried out on the preparation of odorless fish-starch flakes using partially deodorized trash fish meat and different sources of starch like corn, tapioca, maida and black gram. It has been found that the products using corn and tapioca are better compared to those prepared using other two starches, the product from corn being the best. The product has a protein content of about 20% and has been found to have a storage life of 4 months at 37°c.

On the comparative efficiency of conventional and bulged belly fish trawls

To ensure a greater vertical opening while under tow, a trawl net with a bulged belly was made and compared with a conventional design under actual fishing conditions. It was found that the new design landed 31.8% more fish. Since the percentage lateral spread was relatively less for the bulged belly net, it was inferred that this net had higher head line height, while under operation and this was further substantiated by a greater catch of off—bottom fishes. Further, half the quantity of twine can be saved by changing the conventional trawl to that of bulged belly type.

Studies on transportation of fish. Pt. 1. Packaging of frozen fish in insulated containers

The paper deals with certain technological aspects of transportation of fish. Frozen fish packed in thermocole insulated plywood box (tea chests) and transported has been found to remain in good condition, for 3 to 4 days. Fish reaching the destination in a thawed state can be stored in crushed ice for a further period of 2-3 days. The effect of initial temperature of frozen fish on the storage life, the maximum storage period for different types of frozen fish packed in the insulated container and the changes in chemical and organoleptic qualities of different varieties of fish under condition of transport are also discussed.

Studies on the preparation of fish protein concentrate

The paper deals with the method of preparation of an edible fish protein concentrate from cheap miscellaneous fish. The method consists in cooking the fish with 0.5% glacial acetic acid, and extracting batch—wise, using ethyl alcohol followed by an azeotropic mixture of hexane and alcohol (B. Pt. 58-68°C). The product is finally vacuum dried during which the residual solvent is also removed. The concentrate prepared by this method contains 85% protein of which 96% is pepsin digestible. The product is practically odorless and almost white in color.

Preliminary trials on the toxicity of "Algistat" to fish and algae

Preliminary toxicity trials conducted with "Algistat" (an algicide) indicated that a dose of 0,66ppm of the compound was highly toxic to fish and 0.8ppm was the general lethal level for Spirogyra sp. The blue green algae, Oscillatoria sp., Mycrocystis sp. and Anabaena sp. were adversely affected by dosages higher than 0.5 ppm Euglena sp. was not affected even at 1.0 ppm.

Transportation of fish in India: problems and prospects

India has a long coast line of about 4,800 km along which fish landing centers are scattered. Fish catches are showing an upward trend consequent on rapid mechanization of fishing crafts. Economic utilization of the landed fish is an essential prerequisite for the proper development of Indian fishing and fish processing industries.

An accelerated method of hot air drying of fish

The effects of temperature and relative humidity on the rate of drying of split open fish and salted fish in a tunnel dryer have been studied at a constant air velocity. By a judicious combination of these two, the rate of drying could be considerably accelerated, 10 to 12 hours only being required for drying to moisture levels below 30% in the case of mackerel, lactarius, otolithes and kilimeen (Nemipterus japonicus)

Utilisation of trash fish. Pt. 2. Studies on preparation of fish soup mix

The paper deals with the investigations carried out on the preparation of fish soup mix using partially deodorized trash fish meat. The product contained about 25% protein and had a storage life of 4 months at ambient temperature (28-31°C).

Preliminary studies on the effect of irradiation as a means of preservation of fish and shellfish

Preliminary investigations on the effect of irradiation on commercially important fish and shell fish like silver pomfret, Bombay duck and prawns were conducted. Irradiated samples had an extended storage life compared to their respective controls even though yellowish or brownish discoloration occurred earlier in irradiated fish. Irradiation enhanced the rate of drip formation. Brine treatment prior to irradiation retarded this rate. Pre-blanching was found to further extend the storage life of irradiated fish.

Fish and shell fish fauna of the retting and nonretting zones of the Kadinamkulam kayal, Kerala

Retting of coconut husk is one of the major problems of pollution in the estuaries (kayals) of Kerala. Retting activity has resulted in the mass destruction of the flora and fauna and has converted sizeable sections of the kayal into virtual cesspools of foul smelling stagnant waters. Levels of hydrogen sulphide, phosphate and BOD, increased while dissolved oxygen and fish and shellfish fauna decreased in the ambient waters. In the Kadinamkulam kayal a total of 37 species of fishes belonging to 26 families, 5 species of prawn and 2 species each of crabs and molluscs were recorded from the no retting zone, whereas only 20 species of fish in dead condition were collected from the rating zone. Prawns, crabs and molluscs were absent at the vetting zone. Majority of the fish fauna in the kayal were marine forms.

Surimi based dried fish cake

Minced fish prepared from the fillets of the sciaenid fish (Lutjanus sp.) was washed with cold water (<10 °C) three times. The washed muscle was pressed through a piece of fine cloth to a moisture content around 80%. The pressed cake (Surimi) was ground with 2.5% sodium chloride and 3% tapioca starch. The mixed material was shaped in the form of a cake and left for one hour for the gel to set. The cakes were then steamed. The cooled cakes were cut into pieces of 1 cm length x 1 cm width x 0.5 cm thick. The pieces were either dried in an electrical oven at 50°C or dried in sun to a moisture content of 11-12%. Biochemical, bacteriological and organoleptic evaluation revealed that the cakes were in very good acceptable form for 8 months. The cakes could be rehydrated by soaking in water at ambient temperature for half an hour and boiling in water for 10 minutes.