The effects of methoxy-p-benzoquinone and some related compounds on bread quality

Following the identification of (I) methoxy-p-benzonquinone and (II) 2:6-dimethoxy-p-benzoquinone in the chloroform extract of yeast-fermented wheat germ, the bread-improving properties of natural and synthetic preparations of these compounds have been studied. A positive effect of (I) on loaf volume and an adverse effect of both on loaf colour have been found. Preliminary feeding trials on rats have shown no toxic effects at five times the levels of (I) which might occur in over-fermented wholemeal bread. Examination of a range of quinoids has revealed some capable of improving loaf volume but none free from adverse effect on colour which is probably due to chemical instability.