Identification of good Chapati quality wheat cultivar in Chhattisgarh through phenol test

Abstract

The enzyme tyrosinase (Polyphenol oxidase) present in the outer layers of wheat grain react with the phenol and oxidize it to quinines which are subsequently converted to dark colored melanin’s by polymerization & interaction with protein. Intensity of colour depends on the amount of tyrosinase enzyme. Tyrosinase activity is found to be an inherited characteristic for phenol test. Dark colour indicates high polyphenol oxidase activity which is not suitable for good chapatti quality. This technique also may be used in identifying mixture of wheat varieties. The phenol test was carried out on 37 advanced fixed breeding lines which are selected according to their higher yield under different farming conditions. Depending upon the degree of darkness, score was given out of 10.0. The phenol colour reaction is also negatively correlated to with the darkening of the whole grain meal dough and chapatti quality. The entries which made good chapatti with > 8.0 score invariably developed very light brown color. This technique is simple and can be easily used in screening the genotypes for chapatti. Cleaned grains free from damaged kernels or foreign material was ke pt in a petridish. Addition of 1% phenol solution was used to dip in the solution. Keep for 2 hours then drains out the solution and dried the seeds on a filter paper sheet. After complete drying, samples are grade the colour on the scale of 0-10. (Virendra Singh Sohu et al. 2018) Experiment was conducted in 3 replication. Score was mean over five observing individual Since different varieties develop different degree of darkness, total 32 genotypes including 5 checks viz., HD 4730 (0), DBW 110(5.5), CG 1023 (2.5), SUJATA (4.2) & Chhattisgarh Genhu 4 (4.4) (IIWBR progress Report, 2016-17, Quality Vol. IV-55) which had already known the scale of phenol test are taken for biochemical study. There are 16 genotypes viz., CG 1710(4.5), CG 1702(1.2), CG 9103-2(2.2), CG-243-5(2.1), CG -8068-8 (3.5), CG -15-136-1 (3.9), CG 1035-4 (4.1), CG 1503(2.9), CG 8059-14-3(3.1), PYT-BSP-16-28(3.9), CG 1720(3.9), CG 1618(3.8), CG 1714(4.4), CG 9075(3.8), CG 1723(3.9) & CG-15-244-1(3.5) found excellent chapatti quality which have lower scale of phenol test as compare to all these checks.