Quantity and Functionality of Protein Fractions Isolated from 3 Ecotypes of Indigenous Chicken in Kenya

Abstract

The aim of this study was to evaluate the effect of the cluster ecotype and the part of chicken on nutritional composition, and functionality of sarcoplasmic and myofibrillar proteins that are most relevant to the technological features of chicken meat. Over 50 chickens from each ecotype cluster purchased, slaughtered and the meat stored under refrigeration at -20^oC and later on transferred in cooler box on ice and flown to South Africa, at the Durban University of Technology. Protein fractions were extracted with a cocktail of Sodium Chloride buffer (50mM NaCl, 50mM Tris HCl; 75mM DTT and 1mM EDTA at pH 7) and quantified by Bradford method. One dimensional Sodium Dodecyl Polyacrylamide Gel Electrophoresis (SDS PAGE) was applied to separate protein fractions. Emulsifying capacity, emulsifying stability, solubility, and in vitro digestibility were determined on the total protein isolates. Significant differences in band expressions were recorded for the myofibrillar and the sarcoplasmic proteins. The three ecotypes had high quality proteins with all the limiting and essential amino acids at concentrations higher than FAO/WHO recommended daily allowance for adults and children. Distinct protein bands at larger molecular weight proteins >100 kDa, corresponding to Myosin Heavy Chain, medium fractions 75 kDa and 45 kDa and even lower molecular weight fraction <25 kDa were present in the chicken breast and the thighs. It concludes that Indigenous chicken protein isolates’ nutritional and functional properties are affected by part of chicken and ecotype clusters.