For better understanding of the antistaling effect of starch-hydrolyzing enzymes, maltose-, maltotriose-, or maltotetraose-producing enzymes were applied to bread mix and the retrogradation rate of the bread was determined using differential scanning calorimetry. A new amylase isolated from Bacillus subtilis SUH 4-2, which selectively produces maltose and maltotriose from starch solution (amylase II), and another amylase from Streptomyces albus KSM-35, mainly producing maltotetraose and maltotriose (amylase IV), were cloned, characterized, and evaluated as antistaling agents for bread. Addition of amylase II or amylase IV significantly reduced the bread staling rate during 7 days of storage (p < 0.05), and especially amylase IV was as effective as a commercial enzyme, Novamyl. Analyses of the maltooligosaccharide composition of bread suggest that maltotriose and maltotetraose produced by the enzyme reaction are responsible for retarding bread retrogradation.

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Thermal degradation behavior of a WO 3 -TiO 2 monolithic catalyst was investigated in terms of structural, morphological, and physico-chemical analyses. The catalyst with 4 wt.% WO 3 contents were prepared by a wet-impregnation method, and a durability test of the catalysts were performed in a temperature range between 400℃ and 800℃ for 3 h. An increase of thermal stress decreased the specific surface area, which was caused by grain growth and agglomeration of the catalyst particles. The phase transition from anatase to rutile occurred at around 800℃ and a decrease in the Brønsted acid sites was confirmed by structural analysis and physico-chemical analysis. A change in Brønsted acidity can affect to the catalytic efficiency; therefore, the thermal degradation behavior of the WO 3 -TiO 2 catalyst could be explained by the transition to a stable rutile phase of TiO 2 and the decrease of specific surface area in the SCR catalyst.