Effect of type and concentration of nitrogen sources on several characteristics of coconut sap (nira) nata

Abstract

Coconut sap (nira) is tapped from coconut spadix and largely consumed in rural area. Nira must be processed under hygienic environment otherwise it will rapidly ferment due to its perishable characteristic. Processing nira for the production of nata using A. xylinum is considered beneficial not only to add variety in raw material of nata but also to produce a shelf stable product. An experiment designed as two-way treatment was carried out to determine effect of type and concentration of nitrogen sources on total viable count during production of coconut sap (nira) nata, physical characteristics of nata produced from nira including color, hardness, elasticity, water holding capacity and final pH, chemical properties of nata produced from nira including proximate composition and dietary fiber content and also to assess sensory acceptance of nata produced from nira. There were two independent variables applied. The first one is the type of nitrogen source (organic nitrogen, inorganic nitrogen and mixed organic and inorganic nitrogen) and the second one is concentration of nitrogen sources (0.25% and 0.5%). Interaction between between types of nitrogen source and concentration of nitrogen source significantly affected thickness, yield, water holding capacity and color of nata produced from nira. Types of nitrogen sources alone significantly affected pH of nira media. Formulation with 0.25% of yeast extract mixed with ammonium sulphate is the suggested treatment since it gave high product yield (83.7%) with good physical characteristics ( desired thickness, high whiteness, sufficient hardness and thickness) , high sensory acceptance and high dietary fiber content.