No abstract

The enzymic reduction of l-octen-3-one into l-octen-3-ol and 3-octanone in mushroom (Agaricus bisporus) was investigated by using synthetic l-octen-3-one blended with mushrooms and the pH adjusted from 5.0 to 9.0. l-Octen-3-ol can be converted from l-octen-3-one, but the formation does not seem to be affected by the pH value while the formation of 3-octanone was favored at pH 8.0-9.0. It is possible there exists two enzymes that are responsible for the formation of l-octen-3-ol and 3-octanone. However, the presence of a reduction enzyme explains only in part about the origin of l-octen-3-ol in mushroom

No abstract

A simple roasting model using a mineral oil bath was set up to study the effects of coffee proteins on the formation of coffee volatiles during roasting. Green coffee powder was separated into four fractions, and the highest concentration of volatile compounds was observed in the roasted sample of the water extract fraction. Sugar degradation products were the dominant compounds. The addition of coffee proteins into the nonprotein water extract fraction catalysed sugar degradation and enhanced the production of selected volatiles. Higher amounts of coffee protein correlated with the concentration of pyrazines. Coffee protein also increased sucrose degradation in the roasting of sucrose with coffee protein. However, the results from colour measurements indicated that a greater amount of protein produced a lighter colour. These results demonstrated the important contribution of coffee proteins in the formation of coffee volatiles and colour.

No abstract