Effects of heat treatment and dehydration on properties of cauliflower fiber

The effects of heat treatment and dehydration on fiber structure and hydrat ion properties, using cauliflower floret/curd and stem tissues, have been i nvestigated. No major changes in fiber composition resulted from sample tre atments, but the degree of esterification of pectic polysaccharides, simila r to 60% in fresh cauliflower, decreased by similar to 12% in samples heate d at temperatures >40 degrees C. Enzymic activity was considered to be resp onsible, through pectin methyl esterase activity. Deesterification was temp erature and moisture sensitive. Hydration properties were also affected by processing conditions. The solubility of nonstarch polysaccharides in fresh , freeze-dried, and 40 degrees C dried samples was similar to 6% but increa sed to 12% in boiled samples and decreased in samples dried at 75 degrees C . Similar behavior occurred for swelling and water retention capacity (WRC) , with swelling and WRC highest for boiled samples and lowest for samples d ried at 75 degrees C. Hence, a decrease in de-esterification was not direct ly responsible for changes in hydration properties. The results demonstrate the importance of processing history on functional properties and on the p reparation of fiber-rich ingredients for successful incorporation into food s.