Environmental Effects on the Biochemical Phases of Malt Kilning

Sorghum β-Amylase Production: Relationship With Grain Cultivar, Steep Regime, Steep Liquor Composition and Kilning Temperature

“…It is thus possible that the net enzyme synthesis be higher at 50°C for regime I malted grains than at 40°C if the rates of enzyme activation are significantly higher than corresponding values at the lower temperature. On the other hand, enzyme activity at 50°C drying temperature could be higher than that for green malts if more enzyme development/activation took place during the kilning phase at the higher temperature, and if the cumulative rates of enzyme development/activation were higher than those for their inactivation as has earlier been proposed by Lloyd 18 . Steep regime greatly influenced (p < .001) the manner in which malt ␤-amylase activity was affected by the interaction of steep liquor chemical composition with kilning condition (Table III).…”

“…The significantly (p < .001) higher ␤-amylase activity given at 40°C kilning temperature, if compared to values at 50°C, suggests the possible development of markedly more enzyme during the kilning process at the lower temperature, as well as a possibly higher loss of enzyme activity at the higher temperature of drying, most likely due to faster kilning phase transition to the enzyme-denaturing phase 18 . Higher air-on temperatures during kilning have been linked to faster synthetic-to-curing phase transitions 18,24 . It is thus likely that a faster onset of the malt curing phase and a subsequent lengthening of that phase at the higher drying temperature may have been additionally responsible for the lowered ␤-amylase activity at 50°C.…”

“…Some increases in enzyme activity have been reported to occur during the kilning phase of cereal malt production, its extent being controlled by (a) the length of the kilning process, and (b) the initial air-on temperature 18 . The significantly (p < .001) higher ␤-amylase activity given at 40°C kilning temperature, if compared to values at 50°C, suggests the possible development of markedly more enzyme during the kilning process at the lower temperature, as well as a possibly higher loss of enzyme activity at the higher temperature of drying, most likely due to faster kilning phase transition to the enzyme-denaturing phase 18 .…”

“…With NaOH, KOH and the distilled water liquors, instances existed where malt ␤-amylase activity at 50°C was higher than the value for the corresponding green malt but less than enzyme activity given by the matching 40°C-dried malts. In such cases, it is suggested that the higher ␤-amylase activity at 50°C (vis-à-vis green malts) may have been essentially due to kilning phaseassociated de novo enzyme synthesis 18,24 rather than to zymogen activation. It is nevertheless possible that zymogen activation may have been additionally responsible for this post-germination phase increase in sorghum malt ␤-amylase activity.…”

An accelerated malting procedure - influences on malt quality and cost savings by reduced energy consumption and malting losses

“…The first wet steep was extended and the second steep shortened to further improve cytolytic modification (36), while the germination temperature was decreased slightly to compensate for the expected increase in malting loss. Furthermore, the initial withering temperature was increased to further decrease the loss, by reducing growth during the first of the three kilning phases (37,40,41,43). Reinikainen et al (73) demonstrated a 2-to 4-fold respiration by measuring the CO 2 production during the first hours of withering compared with the germination, proving enhanced growth in the germination phase and that withering at higher temperatures resulted in a lower malting loss (59).…”