The Effect of Germination Time on the Final Malt Quality of Buckwheat

Abstract

Common buckwheat (Fagopyrum esculentum) was germinated for different times and buckwheat malt quality was assessed. Deculming losses increased up to a germination time of five days because of an increased rootlet length. α-Amylase activity levels increased, particularly in the first three days of germination, thereafter, activities levelled off. Soluble β-amylase activity levels reached a maximum value after five days germination, whereas the total β-amylase activity level was still increasing at this point. Amylolytic activities, and hence, extract values, were low in comparison with barley malt, but mashing procedures can be optimized, producing commercially desired extracts. Filtration rates increased with increased germination time, while viscosities of buckwheat worts decreased after four days of germination. HPLC analysis demonstrated that maltose and glucose were the main sugars present in buckwheat worts. Total soluble nitrogen, Kolbach index, and free amino nitrogen (FAN) values increased with increased germination times because of a more extensive protein hydrolysis. Free amino acid profiles of buckwheat malts showed that amino acids belonging to class III increased continuously throughout germination. The optimum germination time of buckwheat germinated at a temperature of 15°C was four or five days. After this time, the grains were sufficiently modified but nutrients have not yet been exhausted.