Document Type : Primary Research paper
Department of Aquaculture, Faculty of Fisheries, Kasetsart University, Bangkok, Thailand
Faculty of Agricultural Technology, Valaya Alongkorn Rajabhat University, under the Royal Patronage, Thailand
Faculty of Veterinary Medicine, Kasetsart University,Kamphaeng Saen, Nakhon Pathom 73140, Thailand
Aquaculture has the potential to revolutionize the global food supply chain by providing a source of nutrition for the world’s growing population. This will require the ready availability of high-quality aquaculture feed, and especially its main ingredient, fishmeal. Yet legislation targeting IUU (Illegal, Unreported and Unregulated) fishing strictly controls the usage of fishmeal. Consequently, numerous fishmeal replacement products have been introduced to the market. Yet many such replacements, composed of plant materials, contain high levels of indigestible and antinutritional factors. Thus, supplementation with enzymes, such as protease, is a crucial way to increase products’ digestibility by aquatic animals. A key limiting factor, however, rests upon the manufacturing techniques for aquaculture feed, which require the usage of high temperatures, as heat can diminish enzyme ability. This study is designed to find a solution to this problem, with the use of encapsulation and coating techniques. The ability of encapsulation of 0.25-1% alginate, and of coating materials – chitosan, Seal 4, pullulan and carboxymethyl cellulose (CMC) – to limit the leaching of protease from shrimp feed are observed. The retention capacity of alginate encapsulation is measured by determining the extent of protease leaching in calcium chloride solution. To test coating materials, feed is soaked in distilled water for 30 min, with the resulting solution from each treatment analyzed for protease activity. The results show that encapsulation with 1% alginate retains the most protease (87.63% and 80.56% from protease I-White and II-Brown respectively); and coating with pullulan and CMC results in the least protease leaching (0.200% and 0.210% respectively). To conclude, 1% calcium alginate gel is the most effective product for protease encapsulation, and pullulan is the most effective shrimp-feed coating in terms of its protease retention capacity.