Protein Changes During Malting of Buckwheat

摘要

The proteinases of germinating common buckwheat (Fagopyrum escu-lentum) hydrolyze storage proteins into amino acids and small peptides that can be used by the growing plant or by the yeast during brewing. They are critical for malting and brewing processes because several aspects of brewing are affected by the amounts of proteins, peptides, and amino acids in the wort. Proteins in unmalted, steeped, germinated, and malted buckwheat were fractionated on the basis of their differential solubility and analyzed using a "lab-on-a chip" version of size-based capillary electrophore-sis. In addition, proteolytic activity during buckwheat malting, along with the amino acid composition of the fractions, was investigated. Overall, it was observed that during malting there was a degradation of proteins in all four fractions of buckwheat, along with the appearance of new protein bands in the albumin and glutelin fractions. This is possibly indicative of enzyme synthesis, whereas the complete disappearance of protein bands in the globulin and glutelin fractions is most likely a result of complete protein degradation. The results concurred with changes observed in the free and total amino acid levels. Although earlier work investigated the susceptibility of buckwheat protein fractions to proteolytic action, the present work investigates the changes in buckwheat protein fractions and total amino acid composition throughout the overall malting process.