Germination of Wheat Grains at Various Temperatures in Relation to the Activities of α-Amylase and Endoprotease

Effects of Preharvest Sprouting on Flour Pasting Viscosity in Common Buckwheat (Fagopyrum esculentum Moench)

“…The processing quality of preharvest grain has been studied in detail in wheat. Wheat sprouting increases α-amylase activity (Noda et al, 2001;Ichinose et al, 2002) and causes stickiness of dough and poor handling (Hirano, 1971;Lorenz et al, 1983), greater cooking loss and decrease in stickiness of boiled pasta (Grant et al, 1993), and greater cooking loss and inferior palatability in udon noodles (Nagao, 1984). In buckwheat cultivars, RVA peak viscosity is negatively correlated with hardness of boiled dough (Mukasa et al, 2003).…”

“…There are some reports that sprouting proportion is negatively correlated with pasting viscosity in wheat (Barnard, 2001;Humphreys and Noll, 2002), and the degradation of pasting viscosity was suggested to be caused by α-amylase, which was activated by water or humidity in the grain. Some wheat cultivars produce α -amylase in the absence of visible sprouting (Ichinose et al, 2002).…”

“…Sprouting buckwheat grains have little market value (Bluett, 2001), because some buckwheat millers and manufacturers speculate that fl our made from sprouting grains leads to fragile noodles. Preharvest sprouting occurs in other cereals such as wheat, and seriously degrades grain quality (Kruger, 1990;Noda et al, 2001;Ichinose et al, 2002;Chakraborty et al, 2003).…”

Evaluation of Cultivar Differences in Preharvest Sprouting of Common Buckwheat (Fagopyrum esculentumMoench)

“…differences (Reddy et al, 1985;Ichinose et al, 2002;Nyachiro et al, 2002). Therefore, it would be safer to use an incubation temperature that is similar to that of the natural environment in a germination test for preharvest sprouting evaluation.…”

“…Our experiment showed that buckwheat germination shortly after maturation is promoted by higher temperature (Table 2), consistent with previous reports (Singh and Mall, 1977;Samimy, 1994). This reaction to temperature is opposite that of wheat, in which lower temperature induces preharvest sprouting (Reddy et al, 1985;Ichinose et al, 2002;Nyachiro et al, 2002). The promotion of germination by higher temperature explains why preharvest sprouting in buckwheat occurs frequently in summer cultivation when the temperature in the harvesting season is higher than in autumn cultivation.…”