Production, Properties and Shelf - Life of Intermediate Moisture Snail Meat

Abstract

This research was carried out to study the influence of three cooking methods (frying, smoking and roasting) on the physicho-chemical properties and the shelf – life of snail meat (Achachatina marginata). The snail meat was first washed using different washing agents (lime, alum, salt and ash) and through sensory evaluation, the best washing agent was selected and used to prepare snail meat samples for subsequent processing. The snail from the best washing agents was divided into 4 portions to correspond to the following curing humectant which were used in cook-soak equilibration: salt alone, salt + glycerol, salt + k-sorbate and salt + k-sorbate + glycerol. The cured samples were analyzed for proximate composition, mineral, microbial characteristics and sensory properties. Portions of products from each curing solution were subsequently subjected to three different methods of cooking namely smoking, frying and roasting. These products were also stored at ambient conditions (280C – 320C) for 31days and analyzed at 6day interval for indices of shelf – stability which included water activity, protein solubility, TBA values, pH and microbial quality. Results showed that lime - washed snail meat had the highest score for overall acceptability and had similar scores for color, odor, texture and proximate composition with samples washed with salt, alum and ash. Lime - washed snail meat was then selected for further processing. Curing with various humectants did not lead to significant differences (p>0.05) in sensory characteristics except that samples cured with salt + glycerol + k-sorbate solution was judged to be tougher/harder and the color was neither liked nor disliked compared to others. Curing also reduced the moisture content due to osmotic dehydration but due to concentration effect, increased the protein, fat, ash, zinc, total pigment and pH. Among the cured products, those containing glycerol were higher in moisture content but lower in water activity. The different methods of cooking/preparation (smoking, frying, roasting) had different effects on the shelf stability of the products. In all the 3 methods, samples containing glycerol were lower in water activity, protein solubility, lipid oxidation (TBA), pH and total viable count. The differences caused by curing humectants were maintained during storage. Products treated with salt and those treated with salt + k-sorbate were so unstable that incipient spoilage, which set in caused discontinuation of storage after 1-2 weeks. Smoking caused all the cured snail meat products to be stable throughout the thirty-day storage. Roasted products were least stable during storage; hence, samples cured with salt alone and those cured with salt + k-sorbate spoiled in 7 days in the roasted samples.