Fish. Techno!. (1982) 19, 101-103 101

oluble rotein Isolates from Low Cost Fish and fish astes

A. LEKSHMY NAIR and K. GOPAKUMAR Central Institute of Fisheries Technology, Cochin-682 029

The method of preparation, composition, amino acid content, protein efficiency ratio and areas of possible application of water soluble protein isolates from low cost fish and fish wastes are discussed in detail in this communication.

One of the most widely spread nutritional Methods of preparation, composition, deficiencies in the world today is that of nutritive value and probable areas of use high quality protein. A large proportion of protein isolates from fish and fishery of India's population subsist on cereal grains, wastes are presented in this paper. the proteins of which are low in quantity as well as in quality. Protein malnutrition Materials and Methods is, therefore, an important cause of infant mortality, stunted physical growth, low Fresh fish were collected from fishing work output, premature ageing and reduced boats and were used either immediately or life span. frozen whole and stored at-23oC for future use. Papain was used as the proteolytic A major portion of the marine fish catch agent. Hydrolysis of the comminuted fish in India (1.06 lakh tonnes per annum) is flesh was carried out by the method of constituted by low cost fish of several species Thankamma et a!. (1979). Moisture, ash, obtained as by-catch from shrimp trawlers protein and fat were determined as per (Anon, 1979). Besides this a good percen­ AOAC (1975). Amino acid distribution tage of quality fish goes as waste during of the hydrolysates was determined micro­ processing. Determination cf the proxi­ biologically by the method of Shockman mate composition of several species of (1963) and biological evaluations were Indian miscellaneous fish has shown that performed on albino rats as growth expe­ their protein content varies from 16.0to20.8 g riments according to the method of Chapman per 100 g cf whole minced wet fish (Kutty et a!. (1959). The diet contained 10% protein Ayyappan et a!., 1976). Wastes from fil­ and casein was used as the reference stan­ leting and canning of quality fishes contain dard. Supplementation of the hydrolysate 12.4 to 13.6% crude protein. was done by admixture with the limiting amino acid at 0.1 % level or casein (1: 1). Protein hydrolysates in various forms are presently used in therapeutics as a source of readily assimilable protein in gastro­ Results and Discussion intestinal and liver disorders and in the treatment of severe cases of protein malnu­ The yield of protein hydrolysate from trition (Elman, 1947; Trowell et a!., 1954; trash fish and fish waste are given in Table 1. Bose & Guha, 1961). Starting materials The products were usually golden yellow for such hydrolysates are usually liver, to brown hygroscopic powders and could meat, fish, casein, vegetable proteins etc. be stored in screw-capped glass or polythene For the past few decades several workers bottles with proper wax coating. The (Sen, et a!., 1962; Tarky et a!., 1973; shelf-life of the products from threadfin Yanez, et al., 1976) have attempted to bream, jew fish and lizard fish and cat fish develop methods for conversion of low cost waste were studied for 6 to 12 months. fish and fishery wastes into acceptable and The solubility and colour of the products highly nutritious soluble preparations. remained unaffected.

Vol. 19, 1982 102 A. LEKSHMY NAIR AND K. GOPAKUMAR

Table 1. Yield of protein hydrolysate from low cost fish and fish waste

Substrate Yield (%)

Dry solublesjWet fish of fish waste

Lizard fish ( Saw·ida tumbil) 13.3 Jew fish ( Johnius sp.) 10.6 Thread:fin bream (Nemipterus japonicus) 12.0 Cat fish (Tachysurus sp.) 10.9 Cat :fish waste 4.0 Perch (Nemipterus bleekeri) 7.5 Milk fish ( Chanos chanos) waste 8.1 Jew fish waste 7.8

Table 2. Composition and properties of protein hydrolysates

Lizard fish Thread:fin Milk :fish whole bream whole waste Moisture ( %) 5.0 3.5 1.6 Protein(%) 83.1 86.4 93.1 Fat(%) 0.1 0.1 Nil Ash(%) 5.4 7.6 5.2

Colour Pale brown Reddish brown Creamy yellow

Solubility Instantly and completely soluble in. water

Proximate composition and other proper­ Table 3. Essential amino acid profile of ties of few hydrolysates are presented in hydrolysate from threadfin bream Table 2. The protein content of the iso­ lates was about 90% on dry weight basis Amino acid (g/100 g and fat content was negligible. Usually protein) the samples were rich in lysine and showed excellent amino acid profiles. Amino acid Essential amino FAO pro­ Protein pattern of a typical hydrolysate from thread­ acid visional isolate fin bream is presented in Table 3. Chemical pattern score was calculated using the amino acid scoring pattern proposed by FAO/WHO Isoleucine 4.0 5.6 (1973). The limiting amino acids were Leucine 7.0 7.6 tryptophan and threonine and the chemical Lysine 5.5 9.4 score was 80. Methionine+ Cystine 3.5 5.0 Phenylalanine + The results of nutritional evaluation of the Tyrosine 6.0 6.4 hydrolysate as such and after supplementa­ Threonine 3.9 tion are shown in Table 4. The rats 4.0 Tryptophan 0.8 showed slight diarrhoea when fed on diet 1.0 Valine 5.0 5.2 with hydrolysate alone. The food intake was low and the protein efficiency ratio was inferior to that of casein. However, supple­ with casein brought about a significant mentation of the hydrolysate with the limi­ change in nutritive value and gave PER ting amino acids at 0.1% level or admixture values almost equivalent to that of casein.

FISHERY TECHNOLOGY PROTEIN FROM LOW COST FISH 103

Table 4. Nutritional evaluation of hydro~ Elman, R. (1947) in Advances in Protein !ysates from threadfin bream':' Chemistry (Anson, M. W. & Edsall, J. T. Eds.) Vol. 3, p. 288, Academic PER Press Inc., New York

·Casein 2.8 FAO/WHO (1973) Energy and Protein Hydrolysate 1.8 Requirements, p. 63, FAO, Rome Hydrolysate supple~ mented for limiting Gopakumar, K. (1973) Proceedings of the amino acid 2.4 Second Workshop on All India Co-OJ·di­ Hydrolysate + nated Research Project on Utilization of Casein (1 : 1) 2.7 Trash Fish, ICAR, Mangalore, April 1973 (unpublished) ':'Protein at 10 % level Gopakumar, K., Vasanth Shenoy, A., Kutty Ayyappan, M.P., Arul James, M. Areas of fortification & Iyer, K. M. (1975) Proceedings of the Symposium on Fish Processing Indus­ Methods of preparation and results on try in India. Mysore, India, p. 68, consumer acceptability studies on high Assoc. Food Scientists & Technologists energy food incorporating fish hydrolysates (India) & CFTRI, Mysore have been reported (Gopakumar, 1973; Prabhu eta!. 1975; Gopakumar eta!; 1975). Gopalan, C., Ramasastri, B. V. & BaJa­ Protein content of commercial cereals, the subramanian, S. C. (1980) Nutritive staple food in developing countries, is value of Indian Foods, National Insti­ between 6.2 to 13.6 g per 100 g of edible tite of Nutrition, ICMR, Hyderabad, portion of foods (Gopalan et a!., 1980). India, p. 60 Amino acid profiles of cereal grain proteins often deviate from the needs of man and Kutty Ayyappan, M. P., Shenoy, A. V. & animals, lysine being the first limiting Gopakumar, K. (1976) Fish. Tech­ amino acid for most of them (Block & no!. 13, 153 Mitchell, 1946). The fish hydrolysate is high in lysine (Table 2) and may be used Prabhu, P. V., Raclhakrishnan, A. G. & for incorporation in cereal and other foods. Arul James, M. (1975) Fish. Techno!. 12, 127 The authors are thankful to Dr. C. C. Pandu­ ranga Rao, Director, Central Institute of Fisheries Sen, D. P., Sripathy, P. & Lahiry, N. L. Technology, Cochin for permission to publish the paper. (1962) Fd Techno!. 16, 138

References Shockman, G. D. (1963) in Analytical Microbiology (Kavanagh, F., Ed.), Anon (1979) Annual Report, Central p. 567, Academic Press, New York Marine Fisheries Research Institute, Cochin p. 43 Tarky, N., Agarwala, 0. P. & Pigott, G. M. (1973) J. Fd Sci. 38, 917 AOAC (1975) Official Jo.1ethods of Ana­ lysis, 12th Edn., Association of Official Thankamma, R., Gopakumar, K., Lekshmy Analytical Chemists, Washington Nair, A., Vasanth Shenoy, A. & Arul Block, R. J. & Mitchell, H. H. (1946) James, M. (1979) Fish. Techno!. 16, 71 Nutr. Abst. Rev. 16, 249 Trowell, H. C., Davies, J. N. P. & Dean, Bose, A. N. & Guha, P. K. (1961) Symp. R. F. A. (1954) "Kwashiorkar" p. 185 on Proteins, Mysore, India (Aug. 14-16, EdwardArnold(Publishers) Ltd., London 1960), p. 397 Chapman, D. G., Castillo, R. & Campbell, Yanez, E., Ballester, D., Monckeberg, F., J. A. (1959) Can. J. Biochem. Phy­ Heimlich, W. & Rutman, M. (1976) siol. 37, 679 J. Fd Sci. 41, 1289

Vol. 19, 1982