Utilization of prawn waste: isolation of chitin and its conversion to chitosan

process is described for the preparation of chitosan from prawn waste. The process involves extraction of protein using 0.5% sodium hydroxide solution, bleaching the protein free mass with bleach liquor containing 0.3-0.5% available chlorine followed by demineralisation with 1.25 N hydrochloric acid in the cold and deacetylation using 1:1 (w/w) sodium hydroxide solution at 100°C for 2 hours.

Shrimp extract from prawn waste

A method has been described for the preparation of protein extract from prawn waste. The process consists of extracting the protein from minced fresh prawn head and shell waste by treatment with mild alkali and neutralisation and concentration of the filtrate into a semisolid consistency. The yield of the final product is about 20% of the weight of fresh prawn waste.

Chitosan from Squilla

Squilla (Oratosquilla nepa) is abundant along the west coast of India, inhabiting burrows in sand and mud. The species is little used as it possesses little meat. There is great similarity between chemical composition of Squilla and prawn waste, and it is suggested that Squilla could therefore be used for making chitosan, a potential industrial chemical with various uses. Preparation of chitosan, and the general nature of the prepared product, is described.

Studies on phenolase enzyme in prawns. II. The inhibitory action on the enzyme by certain chemical agents

The effect of certain chemical agents on dopa oxidation by phenolases has been examined. Sulphur containing amino carboxylic acids are inhibitory agents for dopa oxidation. Tyrosine, a substrate for the enzyme also acts as an inhibitor for dopa oxidation by the enzyme. The possible mode of action has been discussed. The function of diethyl dithiocarbamate in suppressing the display of enzyme activity has been detailed and its behaviour has been compared to the other chemical agents studied.

Seasonal variation in the chemical composition of pomfret - 2. Silver Pomfret (Pampus argenteus)

Seasonal variation in the proximate composition of different body regions of Pampus argenteus is reported. The fat content of the fish is high during winter whereas during summer the fish becomes lean. A comparison of average values of proximate composition and energy values of silver pomfret and black pomfret (Parastromateus niger) is given.

Utilization of the fish waste self-brine of fish curing industry as farm fertilizer

Large quantities of self-brine accumulating in curing tanks during the process of commercial fish salting is mostly wasted at present. This liquor exuded from the fish during the process of salting contains considerable amounts of soluble proteins and minerals. Due to the presence of organic matter the self-brine quickly putrefies causing nauseating smell. This renders the whole surroundings insanitary and often leads to health hazards to neighboring localities. Any economic method of utilising this waste brine and converting it into some useful product will be a tangible help to the fish curing industry. Hence, a method is given for converting this waste self-brine into a cheap and efficient fertilizer.

Chemical control of psychrophilic bacterial spoilage of fish 1. Isolation and identification of psychrophilic bacteria from marine fish

Making use of the streak plate technique and low temperature incubation, 28 cultures belonging to six genera namely, Achromobacter, Flavobacterium, Pseudomonas, Micrococcus, Vibrio and Alcaligenes were isolated from different varieties of marine fish. The growth studies indicated that all of them were able to grow between -5 and +5°C within a week's time and none of them showed growth at 37°C. The optimum temperature of growth for all these cultures was in the range 25-28°C. Among these only one, i.e., a Vibrio sp., was found to be an obligate psychrophile.