CORE Metadata, citation and similar papers at core.ac.uk Provided by Aquatic Commons PART II SCIENTIFIC AND TECHNICAL IOC E l VESTIGATI s 0 E EDI lE llUSCS f lie STUDY ON THE UTRITIONAL VALUE OF SO E GASTROPODS D CEPHALOPODS H. SURYANARAYANAN, R. SHYLAJA KUMARI AND K. M. ALEXANDER Department of Zoology, University of Kera/a, Kariavottom-P. 0., Trivondrum, india Data on the biochemical composition and food value of the edible portions of two gastropods, Pila virens and Achatina fulica and two cephalopods, Sepiella inermis and Loigo indica have been presented. These molluscs posses nutritive meat very rich in protein and mine­ rals, which compare favourably with popular food fishes in caloric value. The significance of the variations met with in the bioche­ mical constituents of the different species has been di~cussed. INTRODUCTION inland waters and west c:;ast of Kerala would provide valuable data regarding Apart from prawns and shrimps, their nutritional value aad pave way for various molluscs such as squids, mussels, better exploitation and utilization of the oysters and clams comprise the major part molluscan fisheries of Kerala. The present of shell fishery. As a matter of fact these report, dealing with the nutritional value molluscs constitute a comparatively unex­ of certain edible gastropods and cephalopods ploited fishery resource of great promise is the continuation of an earlier publication by virtue of their high productivity and on the edible bivalves (Suryanarayanan natural abundance (Jones, 1968). Despite and Alexander, 1972). the considerable data available on the biochemical aspects of fishes of India MATERIAL AND METHODS (Saha and Guha, 1938; Giri et, al, 1944: Venkitaraman and Chari, 1955: Alexander, Adult specimens of the fresh water 1955, 56) investigations on the edible moll­ gastropod, Pila virens, the terrestrial pul­ uscs have been rather few (Joshi and Bal, monate, Achatina fttlica and two cephalo­ 1968; Chinnamma et al, 1970; Pandit and pods, Loligo indica and Sepiella inermis Magar, 1972). Hence it was thought that were collected from their natural habitats a study of the various biochemical constitu­ and were brought to the laboratory in live ents of the edible molluscs found in the condition. They were later killed and their 100 FISHERY TECHNOLOGY Suryanarayanan, Sllylaja 'Kumari & Alexander: 13iocftemical investigations on tfte edi5le molluscs of 'Kerala. II- A study on tfl.e nutritional value of some gastropods and cepfwlopods edible portions were analysed for moisture of 0.53% (Sepiella inermis) and 0.61% content, total proteins, free amino acids, ( Loligo indica). total lipids, glycogen, iron, phosphorus and ash content employing standard analytical All molluscs investigated revealed a techniques (Suryanarayrnan and Alexander, fairly high percentage of lipids, 5.56% in 1972). The food value was calculated Sepiella inermis, 5.4% in Loligo indica, 4.4% using Rubner's (1901) Table. in Pi/a virens and 10.8% in Achatinafulica. The highest value for iron content is RESULTS shown by Achatinafulica (153.8mg%) while The data obtained for the various Pila virens has a lower value of I24.4mg%. biochemical constituents of these edible Relatively very low percentages, 16.64 mg% molluscs are given in Table I and II. in Loligo indjca and 12.88mg% in Sepiella inermis) have been observed. The p~rcentage of edible portions is· comparatively high in cephalopods ranging The phosphorus content of cephalopods from 68.5% (sepiel!a inermis) to 71.38% is rather high (138.0mg% in Sepiella i~termis (Loligo indica) whereas the gastropods, and 145.0mg% in Loligo indica) whereas Pila virens and Achatina fulica have only both gastropods have much lower values 29.08% and 24.7% respectively. (62.5mg% in Achatina fulica and 83.0mg% in Pila virens). The moisture content in the cephalo­ pods is rather low being 74. 78% in Sepiella Sepiella inermis and Loligo indica inermis and 75.05% in Loligo ·indica. Of the showed a comparatively higher percentage two gastropods studied, Pila virens has a of ash content, 13.42%, 12.5% respectively moisture content of 78.87% and Achatina than Pita virens (10.96%) and Achatina fulica, 75.5%. fulica (6.3%). Relatively, the cephalopods have the The ener_gy content of these molluscs highest protein content of 83.49% in Loligo range from 453.42 calories in Achatina indica and 81.49% in Sepiella inermis. fulica, 379.83 calories in Pila virens, 395.05 The gastropod pila virens has only 75.32% calories in Loligo indica to 387.99 calories and Achatina fulica, 76.2% . in Sepiella inermis. The edible portions of the molluscs DISCUSSION investigated appeared to possess aU or most of the following amino acids namely, The data suggest that' among the arginine, cysteine, glutamic acid,_ molluscs studied, the percentage of edible glycine, histidine, isoleucine, leucine portions is rather high in cephalopods ( 68.5% lysine, methionine, phenylalanine, serine to 71.38%) whereas the gastropods possessed threonine, tryptophan, tyrosir:e and valine. only lower percentage (24.7% to 29.08%). Table II shows the free amino acids in the In fact the higher percentage of edihle different animals concernd. portions found in cephalopods could be attributed to their possession of light inter­ Regarding the glycogen content, Acha­ nal shells. Among the two gastropods, tina fulica shows the highest percentage of Achatina fulica has a relatively heavier shell 10.4%and Pila virens 7.2%. Nevertheless, the which would explain its lower percentage cephalopods exihibit only very low values of edible tissue: Since both gastropods and VoL X No. 2 1973 101 0 -N d()') £.~ ... -!':!<.<::: (")"' c;::! TABLE 1. "' c 0 'I BIOCHEMICAL COMPOSITION OF THE EDIBLE PORTIONS OF THE MOLLUSCS STUDIED -c ~II::: (\) c "' ;s Food value o e Animals %of edible Moisture Proteins Lipid Glycogen Phosphorus Iron Ash Calories; ~"N "ry, Portionst content t %* mg%* mg%* %* lOOgm.* * :::~I- 0 Pi/a virens 29.08 78.87 75.32 4.44 7.25 83.0 124.4 10.96 378.83 >-~· ~~ Achatina fulica ::: ::: 24.7 75.50 76.20 10 80 10.4 62.5 153.8 6.30 453.42 0-::l '1::: ""0 Sepiella inermis 68.56 74.78 81.49 5.56 0.53 138.0 12.88 13.42 387.99 0 ... ;:; Loligo indica 71.38 75.05 83.49 5.40 0.61 145.0 16.66 12.50 395.03 .... ;,~ ;::-"'>- !':! '1. ·(Expressed as gms/ 100 gms wet weight. .... x ... c ~Expressed as units/100 gms dry weig~t. E:~ 0 (\) TABLE II. ;s ., !?.:" FREE . AMINO ACIDS IN THE V ARlO US MOLLUSCS STUDIED oti] -o1:1 .... !::! (") Phenyls Gly~ Cyst~ Tyro~ Histi. Vali~ Lysi- Methi- Glutamic Insol~ Leuc- Ser- Trypto- Pro- Arg- Thre ">;:to 0 ~ Animals alanine cine tine sine dine ne ne onine acid eusine ine ine phan line inie onine ...... ;:l ()"' (")... :::-- c "' .... <Q ;:l 0 <;I Pila virens + + + + - + + + + + + + + + + + ~;."'"' O<Q ""O0 .... 0- .... :zl. Loligo indica - + - - + - - tl:l + + + + + + + + tn g l:Il 0 tn l:;!'j ;:l - - 0-0 c; Sepiella inermis+ + + + + + + + + - + + (") ;::! + + "'­ "";:;;.;:.."> ~ + indicate presence 2.."'00., ""OQ'> .... ~ o..­ s0 (1) (\) Cl ><: 8uryararayanan, 811ylaja 'Kumari & Alexander: 13iocfiemical investigations on tfte edi(ile molluscs of 'Kerala. II- A study. on tfie nutritional value of some gastropods and cepfwlopods bivalves possess much heavier shells, they muscular activity (Fields, 1965). In con have comparatively lesser percentage of trast to the low glycogen values of cephalo­ edible portions. pods the gastropods store larger amounts of glycogen in their tissues. Infact glycogen The moisture content of the gastropod, constitutes a major fuel reserve of terrestrial Pi/a virens is 78.87% and Achatina fulica gastropods and is utilized as an energy 75.5%. Comparatively lower values have source during hibernation and aestivation been obtained for the cephalopods, Loligo (Meenaks11i. 1958; Thiele, 1959). indica (75.5%) and Sepiella inermis 74.78 %). The lower moisture content in the terrestri­ The lipids in the body and in the diet al pulmonate, Achatina fulica and in the constitute a concentrated form of energy for marine cephalopods could be attributed to metabolism and storage purposes. Further the osmotic requirements of the habitat fats may serve important non-caloric metabo­ concerned. lic functions also(George and Berger, 1966). Relatively, the cephalopods showed much The cephalopods revealed high protein higher percentages of lipids than glycogen content (83.49% in Loligo indica and (5.56% for Sepi?lla inermis and 5.4% for 81.49% in Sepiella inermis). Similar values Laligo indica). The lipid content reported have been reported by Pandit and Mag3:r by Pandit and Magar (1972) for Sepia (1972) for Sepia orienta/is (80.21 %) and orienta/is (3.9%) and Loligo vulgaris Loligo vulgaris (81.50%). It has been sugg­ (4 %) is 'l little lower than those obtained in ested that since the cephalopods possess our present sfujy. The gastropods invest­ only scant glycogen reserves, their inter­ igated also exhibited high lipid content mediary merabolism may utilize body (10.8% in Achatina fulica and 7.2% in Pila protein to sustain life at times of starvation virens). (Goddard and Martin, 1966). Among the gastropods, Achatina fulica has a slightly The ash content of particular animal higher protein content (76.2%) than Pila indicates the amount of inorganic constitu­ virens (72.32%). ents p:esent in its tissue. No significant variation could be observed in the ash Paradoxically the glycogen reserves content of [he two cephalopods, Sepiella exhibited by cephalopods are significantly inermis (13.42%) and Loligo indica 12.5%). low (0.53% and 0.61 %). The present data Lower values have been obtained for the compares favourably with those obtained gastropods, Pila virens (10.96%) and Achatina by Boyland (1928) for Sepiaelegans 0.037% fulica (6.3%). and Eledone (0.11 %). Studies· on fuel re­ serves of molluscan muscle revealed very Among the molluscs investigated, the low glycogen content for cephalopod mus­ gastropods showed much higher percentage cles (Suryanarayanan and Alexander, 1971).