Polyphenol changes in sorghum grain during malting

Abstract

Bird-resistant and non-bird-resistant sorghum cultivars were malted to study effects of tannin on malting as well as changes in polyphenols during malting. No difference could be found in % germination nor in root and shoot production of the malts of the 2 cultivars. There was an increase in anthocyanidin content of roots and shoots during malting. Since there was also an increase in anthocyanidin content of non-bird-resistant kernels, it would appear that there is no migration of anthocyanidins from kernels to roots and shoots. A transmission electron micrograph of the testa after malting showed a testa very similar to that before malting. Tannin in the bird-resistant sorghum picked up extra protein or peptides during malting. Although it was difficult to establish the source of this extra material, amino acid analysis suggested that it was not from the prolamin storage protein in the endosperm