RESUMO
In this study, an attempt was made to substitute maize (Zea mays L.) content of broiler starter feed with ground cassava (Manihot esculenta Crantz) peels enzymatically improved with amylaseproducing fungi with a view to having a cost-effective yet nutritious and health-friendly feed. The biochemical components of the formulated feeds were determined as well as the effect of the feeds on some biochemical parameters in the broiler chicks. Six starter feeds tagged Control Feed, 20%CPFG, 40%CPFG, 60%CPFG, 80%CPFG and 100%CPFG were formulated with respect to variations in maize and cassava peel contents. The results showed a significant (p<0.05) increase in total polysaccharide contents of Feeds 20%CPFG, 60%CPFG, 80%CPFG and 100%CPFG compared to the Control Feed (191.4±14.5 mg/g of feed). Total soluble protein and reducing sugar contents were statistically different in most of the feeds (p<0.05). All the feeds contain relatively high amounts of total phenol (>70 mgCE/g of feed) and most of them comparatively high in anthocyanin relative to the control feed anthocyanin content (225.4±12.2 mg/g of feed). The highest weight gain (108.0±3.0 g) was observed in broiler chicks fed the feed ration containing 60% cassava peels improved with amylase-producing fungi and 40% maize (60%CPFG). Broiler chicks fed the formulated feeds, including the control, exhibited over 40% inhibition against 2, 2-diphenyl-1- picrylhydrazyl (DPPH) radical. The serum activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in birds fed the compounded feeds and control slightly differed except in group 60%CPFG. It was concluded that the maize content in broiler feed can be replaced with cassava peels improved with fungal amylase upto a maximum of 60%. This would significantly decrease the overall cost of broiler feed production without compromising the nutritional, antioxidant and health-friendly potentials of the feed.
RESUMO
Amylases are one of the main enzymes used in industry. Such enzymes hydrolyze the starch molecules into polymers composed of glucose units. Amylases have potential application in a wide number of industrial processes such as food, fermentation and pharmaceutical industries. α-Amylases can be obtained from plants, animals and microorganisms. However, enzymes from fungal and bacterial sources have dominated applications in industrial sectors. The production of α-amylase is essential for conversion of starches into oligosaccharides. Starch is an important constituent of the human diet and is a major storage product of many economically important crops such as wheat, rice, maize, tapioca, and potato. Starch-converting enzymes are used in the production of maltodextrin, modified starches, or glucose and fructose syrups. A large number of microbial α-amylases has applications in different industrial sectors such as food, textile, paper and detergent industries. The production of α-amylases has generally been carried out using submerged fermentation, but solid state fermentation systems appear as a promising technology. The properties of each α-amylase such as thermostability, pH profile, pH stability, and Ca-independency are important in the development of fermentation process. This review focuses on the production of bacterial and fungal α-amylases, their distribution, structural-functional aspects, physical and chemical parameters, and the use of these enzymes in industrial applications.