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.

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.

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).

Preparation of prawn pickle and its storage characteristics

Prawn pickle was produced using smaller variety of prawn. Vinegar and salt was used to preserve the prawn muscle against spoilage. Different spices were used to get desired attractive flavour. Benzoic acid to the extent of 200 ppm was used as preservative. Several trials were carried out using different amounts of spices and different methods of preparation. After each trial the sample was subjected to sensory evaluation by judges consisting of five members who had previous experience of acting as panel members. Several trials were carried out to arrive at a final recipe as judged best by the taste panel. Utilizing this final recipe, a product was prepared and subjected to biochemical, bacteriological and organoleptic evaluation and found to be quite acceptable after seven months of storage in glass jar at ambient temperature. The product was subjected to large scale consumer acceptance trial involving 140 consumers, 42% of them ranked it excellent, 41% rated very good, 12% rated good while 5% of the consumers rated it as average.

Preparation of pasteurized fish ball in curry and its storage study at 0 to 2°C

Fish ball in curry was prepared as per the standardized method and recipe, pasteurized and subjected to storage at 0 to 2°C in a domestic refrigerator. The curry prepared with tomato at a level of 20% of onion was found to be suitable organoleptically. A level of 3% of spice mixture improved the taste of curry. Fish balls prepared with concentrated curry paste and oil at a level of 0.5% was found to be suitable organoleptically. Curry prepared by adding oil at the rate of 3% scored high values for all attributes as compared to other levels. Curry prepared by diluting curry paste with water at rate of 20% had been adjudged the best as compared to other water levels. Fish ball in curry with a 50 : 50 ratio pasteurized at 85°C for five minutes had scored higher values under organoleptic evaluation. It was observed that the product was acceptable organoleptically up to the 12th day when stored at 0 to 2°C.

Preparation of an extruded fish snack using twin screw extruder and the storage characteristics of the product

A value-added extruded fish product was prepared with corn flour (80%) and fish (sciaenid) powder (20%), using a twin-screw extruder. The effect of different parameters like moisture, temperature, fish powder concentration, speed of the extruder and die-diameter on expansion ratio and crisp texture were studied. The storage characteristics of the final product were studied using three different types of packaging under nitrogen flushing. The study revealed that aluminum foil is the best packaging material to keep the product acceptable for more than three months.

Preparation of tetrahedral amorphous carbon films by filtered cathodic vacuum arc deposition

Tetrahedrally bonded amorphous carbon (ta-C) and nitrogen doped (ta-C:N) films were obtained at room temperature in a filtered cathodic vacuum arc (FCVA) system incorporating an off-plane double bend (S-bend) magnetic filter. The influence of the negative bias voltage applied to substrates (from -20 to -350 V) and the nitrogen background pressure (up to 10-3 Torr) on film properties was studied by scanning electron microscopy (SEM), electron energy loss spectroscopy (EELS), Raman spectroscopy, X-ray photoemission spectroscopy (XPS), secondary ion mass spectroscopy (SIMS) and X-ray reflectivity (XRR). The ta-C films showed sp3 fractions between 84% and 88%, and mass densities around 3.2 g/cm3 in the wide range of bias voltage studied. In contrast, the compressive stress showed a maximum value of 11 GPa for bias voltages around -90 V, whereas for lower and higher bias voltages the stress decreased to 6 GPa. As for the ta-C:N films grown at bias voltages below -200 V and with N contents up to 7%, it has been found that the N atoms were preferentially sp3 bonded to the carbon network with a reduction in stress below 8 GPa. Further increase in bias voltage or N content increased the sp2 fraction, leading to a reduction in film density to 2.7 g/cm3.

Studies on the preparation of fish silage. 1. Effect of quality of raw material and type of acid

An experiment was undertaken in which silver bellies (Leiognathus splendens) of different quality were used to produce silages using different concentrations of hydrochloric acid and formic acid. The quality and storage life of the various preparations are reported. Silages which keep for at least 30 days can be produced from silver belly held for 3 or 12 hours at 28°C by: 1) reducing the pH by addition of hydrochloric acid; 2) adding 0.5% formic acid and reducing the pH to 3.5 with hydrochloric acid; or 3) adding 2.5% formic acid.

Studies on the preparation of fish silage. 2. Rate of liquefaction in different parts of silver belly

An experiment was undertaken to determine from which part of silver belly (Leiognathus splendens) carcasses originate the autolytic enzymes responsible for liquefaction of silage. Findings show that it is important to leave head and viscera present in order to get a satisfactory liquefaction in silage prepared from silver belly using 3.5% formic acid. The storage life of silage produced from various parts of the fish carcasses is also discussed.

Studies on the preparation of fish silage. 3. Dried silage products

An investigation was undertaken on the production of dried products from silver belly (Leiognathus splendens) silage mixed with plant filter materials. Silages produced using hydrochloric acid and/or formic acid when mixed with rice bran or maize meal and dried, yielded powders having an acceptable appearance and a pleasant odour, which are suitable for use in compounded chicken feeds.

Studies on the preparation of fish silage. 4. Economics of production

Economic aspects of producing liquid and dried silage from silver belly (Leiognathus splendens) in Sri Lanka are considered. A discounted cash flow analysis for the production of a dried fish silage/rice bran product suitable for use in compounded poultry feeds shows that the internal rate of return for a 10-year project would be between 34-77% and for a 5-year project between 26-73%. Thus it is concluded that the project would be extremely profitable.

Standardisation of recipe for the preparation of lobster analogues

Lobster analogues were prepared with lobster base flavour (paste),h lobster cook water (whole lobster omogenate:water, 1:1 and 1:0.5) and lobster meat mince. In another experiment, different combinations of ginger-garlic paste and lobster base flavour, i.e., 1:3, 1:4, 1:6, 3:3, 3:4, 3:6, 5:3, 5:4 and 5:6 were added to the lobster analogue paste. It was observed that lobster analogues prepared with lobster base flavour (paste) are suitable organoleptically. The combination of ginger garlic paste and lobster base flavour in the ratio of 3:4 was found to be suitable organoleptically. Lobster analogues coloured with annatto seed colour at 1:2 (annatto seed:water) concentration had high values for the colour attribute as compared to orange-red synthetic colour, beetroot colour, caramel colour and paprika colour. It was observed that come-up-time to achieve a temperature of850°C was 28 minutes with a processing period of 11 minutes.

A method for the preparation of cooked-peeled-frozen prawns

Several consignments of cooked-peeled-frozen prawns exported from India were rejected last year due to high total plate count (TPC) at 30°C. The specified temperature of incubation for TPC in our country is 37°C. Hence the effect of incubation at 30 and 37°C on TPC was studied. It is seen that the count is higher on incubation at 30°C. A method for production of cooked-peeled-frozen prawns conforming to the specification for TPC at 30°C is standardized and is reported. It consists of recooking the cooked-peeled prawns followed by packing and freezing without further contamination. The method minimizes batch to batch or sample to sample variation in TPC.