STUDIES TOWARDS IMPROVING PROTEIN QUALITY ASSAY IN QPM

Abstract

Quality protein maize (QPM) is a nutritionally superior commodity having the desired concentration of essential amino acids such as tryptophan and lysine. However, this nutritionally superior maize could not become popular in the absence of any remunerative price for this commodity. The similarity in kernel appearance between QPM and normal maize thus necessitates the development of a rapid assay method to assess the protein quality of QPM. The present study deals with optimization of defatting time, expedition of protein hydrolysis and total protein estimation that are the three major components of tryptophan estimation process. The results revealed that defatting for a period of 48 hours is sufficient for QPM and opaque-2 in order to correctly estimate the tryptophan content. The proprietary formulation developed by IIMR is found to be quite efficient in carrying out complete protein hydrolysis at 120ºC in just 15 minutes. Further, it was concluded that Bradford method is positively correlated to Kjeldahl method (R2= 0.81) and can efficiently be utilized for rapid estimation of protein concentration in maize. Thus, unlike enzymatic method which requires 23 days for defatting, 18 hours of incubation for protein hydrolysis and approximately 23 hours for total protein estimation, the present study is effectively useful to improve protein quality assay in maize