Protein hydrolysate from miscellaneous fish

A method to prepare fish protein hydrolysate from miscellaneous fish obtained as by catch from shrimp trawlers is outlined. Effect of temperature and concentration of enzyme papain on the yield of hydrolysates has been determined. It is seen that within 30 min at 55°C and pH 6.5 fish proteins can be effectively solubilized, provided the nitrogen content of the enzyme (activity 10 units/mg enzyme) and substrate are maintained in the ratio 1:30. This hydrolysate possesses the best amino acid pattern compared to those obtained after hydrolysis for 60 to 180 min.

Beverage preparation from fish hydrolysate

A method for the preparation of energy food incorporating fish hydrolysates, sugar, cocoa, malt extract etc. is described. The product has good consumer appeal. The preparation does not impart any bitter taste of the hydrolysate to the final product irrespective of the type of fish used for preparing the hydrolysate. It freely mixes with hot or cold milk and the resulting drink is adjudged to be very palatable.

A pilot scale set up for the manufacture of fish hydrolysate

This paper describes a set up for a pilot plant with a capacity of 50 kg raw material per batch for the production of fish hydrolysate by enzymatic hydrolysis. Process flow sheet and complete specifications and functions of individual equipment have been described. Multifunctional equipment designed for this pilot plant set up has reduced the number of equipment considerably.

Studies on lantern fish (Benthosema pterotum) 2. Nutritional evaluation

Various methods for processing and utilization of lantern fish (Benthosema pterotum) are reported. Nutritional evaluation of fish meal and fish hydrolysate from lantern fish has been carried out. Growth rate and PER of lantern fish meal are similar and better than that of the reference protein, casein. Lantern fish meal can therefore be extensively used for the formulation of poultry, fish and other animal feeds as a good protein supplement with beneficial effects.

A preliminary study on the evaluation of casein, shrimp meal, squid meal and spirulina as protein sources of Penaeus monodon (Fabricius) postlarvae

P. monodon postlarvae were fed with fresh brown mussel (Modiolus metcalfei ) meat, and artificial diets containing casein, shrimp (Metapenaeus ensis ) meal, squid (Loligo ) meal, and Spirulina as protein sources at a rate of 20% of their biomass per day for a period of 10 days. No statistical difference was found among the weight gains of shrimp fed on various experimental diets. However, shrimp fed squid meal diet had highest weight gain followed by shrimp meal, fresh brown mussel meat, casein and Spirulina . Shrimp fed squid meal diet had a significantly better feed conversion and those receiving other experimental diets. Poorest fed conversion was observed in shrimp fed Spirulina . The protein efficiency ratio was statistically highest for the squid meal diet, with the lowest value again for Spirulina diets. Survival rate was significantly highest for shrimp fed the shrimp meal diet. No statistical differences were found among shrimp fed other experimental diets. Appropriate data are tabulated.

Über Fischereiressourcen und ihre Nutzung

The reduction of discards will only be achieved, if more effective methods of catch selection will be developed and used. In principle, the unavoidable by catch of commercial fish should be used for human consumption, independent of the requirements for minimum length and existing catch quotas. The amount of such bycatch should be charged to the total catch quota and preferably be used for processing of fish portions with skin (carcasses with skin), because this kind of processing results in higher yields and nutrional advantages compared to fillet processing. Unfortunately, nowadays, in the German fishery and fish trade this traditional form of supply is only of minor importance because of the predominance of fillets and fillet products. However, cooperation between fishing industry and fish trade and a good advertising of processed fish portions with skin could overcome this problem. In the pelagic fishery of herring, mackerel and other similar pelagic species the bycatch of small sized specimen of these species can be a problem. These small sized fish can principally be processed to traditional fish products, but the processing costs for them are much higher. The prospects for processing of the bycatch into minced fish meat, fish protein concentrate or fish protein hydrolysate are very poor under the existing regime in the German fishing industry. A further way for processing of the bycatch, which can not be used for human consumption, is the production of fishmeal. However, only three German factory ships dispose of fish meal plants. Under the current economic conditions, i.e. because of limited storage capacity, the Ger-man trawler and cutter fleet is not able to transport the bycatch for fish meal production ashore.

Pyridoxine and survival of tilapia (Sarotherodon mossambicus Peters)

Pyridoxine requirements of tilapia (Sarotherodon mossambicus Peters) were studied in two separate experiments using casein-based diets. In Experiment 1, fish on pyridoxine supplemented diet (14.0mg/100g diet) showed no adverse symptoms and remained healthy while fish on a pyridoxine-free diet showed abnormal behaviour with high mortality. Graded dietary pyridoxine (0.13 to 3.52mg/100g diet) was used in Experiment 2. Lower dietary supplementations of pyridoxine resulted in reduced weight increase, high mortality, high ratio of serum glutamate-oxal-acetate transaminase glutamate-pyruvate transaminase, and reduced blood sugar. The results suggest the dietary requirement of pyridoxine may be between 0.5g and 1.17mg/100g diet; higher supplementations did not appear to confer any further benefits

Functional properties of enzymatically modified protein from fish waste

Fish flour from dried waste consisting of head, tail, fins and entrails was enzimatically hydrolysed using various proteases and the hydrolysate was spray dried. The functional properties such as water-fat absorption ratio, foaming and solubility index of the hydrolysates and fish flour revealed that some of the products might find significant uses in the food and/or cosmetics industry. Electrophoretic separation of the proteins from the fish flour and of the hydrolysates indicated that almost all the flour proteins are susceptible to proteolytic cleavage with the exception of one or two. The extent of degree of hydrolysis from 43-70.3% with a simultaneous decrease in unpleasant smell suggest an economical tool for minimizing odour pollution due to fish industry waste deterioration.

Nutrient digestibility coefficients of diets with varying energy to protein ratio for Japanese flounder, Paralichthys olivaceus

A laboratory trial was conducted in a sea water recirculatory system to study the nutrient digestibility coefficients of diets with varying energy to protein ratios in Japanese flounder Paralicthys olivaceus. Six different experimental diets with two protein levels (45 and 55%) having six different energy to protein ratio of 87, 90, 94, 107, 110 and 114 were formulated using white fish meal and casein as protein sources. The results of the study showed that the apparent protein digestibility (APD) value ranged between 90.59 to 91.61% and there were no significant differences (P>0.05) between the APD values of diets 1, 2, 3, 4 and 6. The apparent lipid digestibility (ALD) values of diets ranged between 88.24 to 90.18%. The apparent energy digestibility (AED) values ranged between 80.55 to 87.52% with diet 3 producing significantly the highest AED value. In general, except in diet 1 the ALD and AED values increased with the increase of dietary lipid at both protein levels. The results of the present investigation indicated that Japanese flounder can efficiently digest the dietary nutrients at varying energy to protein ratios.

Nutritional characteristics of the two fermented fish products: Hentak and Ngari of Manipur

Proximate composition and nutritional characteristics of the two fermented fish products Hentak and Ngari of Manipur (India) were evaluated. Percentage of moisture, protein, lipid and ash contents in Hentak and Ngari were respectively: 36.30 versus 36.03; 33.33 versus 38.38; 13.60 versus 13.34 and 11.43 versus 5.49. Digestibility values in feeding trials in laboratory rats for 28 days were 82.37% for Hentak 89.46% for Ngari and that of Casein was 92.69%. The biological value, food conversion ratio and protein efficiency ratio (PER) of Hentak were 96.94, 4.83 and 1.8 respectively and that of Ngari were 97.83, 3.17 and 1.8 respectively. The α amino nitrogen of Hentak and Ngari in Pepsin + Trypsin phase were 28.40 and 28.92 respectively. The TBA number, peroxide value and TVBN were within the acceptable limits.

Development of partially hydrolysed and deodourised fish flour

A process developed for preparation of partially hydrolysed and deodorised (PHD) fish flour, without solvent extraction is described. The PHD fish flour prepared from four varieties of trash fish had creamy white colour and contained 87-92% protein and 7-8% available lysine. The products had shelf life of more than a year at room temperature, and caused no grittiness when incorporated in snacks and bakery products at 10% and 7.5% level respectively. The flour prepared from Nemipterus spp. had a PER 2.32 compared to 2.68 of raw fish meat and 2.5 of standard casein.

Squilla protein: chemical composition and nutritive value

Protein extract prepared from squilla (Grato squilla nepa), a commercially unexploited crustacean, was analysed for crude protein and essential amino acids. All the essential amino acids except tryptophan and threonine were present in nutritionally adequate amounts. The protein was evaluated for its nutritional quality in respect of growth rate, protein efficiency ratio (PER) and liver nitrogen content by feeding on rats. Growth rates and protein efficiency ratios were similar in rats fed on casein, squilla protein and a combination of squilla protein and casein (1:1) diet. The weight of liver and kidneys were normal.

Nutritional evaluation of fish solubles

This paper reports the results of a preliminary study on the biochemical composition and nutritional charactersitics of fish solubles from oil sardines (Sardinella longiceps) and white tailed pink perch (Nemipterus japonicus). The nutritional quality of sardine solubles has been evaluated by feeding trials using albino rats also. The studies have shown that compared to a control group of rats whose diet had casein as the sole source of protein, a group of rats in whose diet dried sardine solubles replaced half of the casein, had a noticeably higher growth rate. This higher growth rate was not prominent in the early stages of growth (4-7 weeks). But, during later stages (7-10 weeks), solubles incorporated diet supported a distinctly higher growth rate. This effect was more pronounced in female rats (17% over the control group) compared to the male rats (4% over the control group). Fish solubles are found to be poor sources of essential amino acids. Thus, the observed increase in growth rate is higher than the rate expected from the amino acid make up. This probably supports the view expressed by workers elsewhere that fish solubles contain some unidentified growth factors.

Nutritional evaluation of some freshwater fishes

The proximate composition, amino acid composition and the PER values of Rohu (Labeo rohita), Mrigal (Cirrhina mrigala) and Calbasu (Labeo calbasu) are reported. The proximate composition of all the three fishes was similar. However the amino acid composition varied considerably. Protein quality index of the three fish proteins calculated from the amino acid composition are also reported. The nutritional quality of the 3 types of proteins to meet the growth requirements of infants, children and adult human beings is discussed. The possibility of substantial improvement in nutritional quality of the three fish proteins to suit the requirements of infants and children by marginal supplementation with valine/valine-rich food for rohu and valine and isoleucine/food rich in valine and isoleucine for mrigal and calbasu is also discussed. The results indicate that of the three fishes rohu is the best in protein quality followed by mrigal and calbasu. All of them have a better amino acid make up than casein to meet the amino acid requirement of adults.

Formulation, processing and water stability of pelleted feeds with varying levels of protein used in carp nutrition studies

Four dry pelleted feeds containing 20%, 30%, 40% and 45% protein were formulated incorporating casein as the main source of protein for use in carp nutrition studies. The caloric content in all the feeds was maintained constant. The method of processing is described. The formulated diets were tested for water stability. This test has revealed that the diet containing 20%, 30% and 40% protein had better stability than that containing 45% protein. This was due to the relatively higher fat content in the former three diets. However, all the feeds were sufficiently stable at the end of one hour in which time carps are known to utilise supplementary diets.