Retardation of Discoloration in Barley Flour Gel and Dough

Abstract

ABSTRACT Dark discoloration negatively influences the aesthetic properties of barley-based food products. The effects of abrasion and heat treatment of grains, exclusion of oxygen, and the use of antibrowning agents on the retardation of darkening in barley flour gel or dough were determined in four types of barley, including hulled proanthocyanidin-containing and hulled proanthocyanidin-free, hulless regular, and hulless waxy barley. Abrasion by >30% in hulled barley and by >15% in hulless barley significantly increased the brightness (L*) of barley flour dough by 0.1–7.1. Steam heating of abraded grains also significantly increased the L* of barley flour gels by 1.8–3.4. Ascorbic acid at 1,500 ppm was most effective for retarding discoloration of barley flour dough, followed by 50 ppm of 4-hexylresorcinol, which is an enzyme competitive inhibitor. The discoloration of barley flour dough was also effectively reduced by storing the dough sheets at 4°C under nitrogen gas to exclude oxygen or under anaerobi...