作者 Prakash, Anuradha
書名 The effect of microwave energy on the structure and function of food hydrocolloids
說明 165 p
附註 Source: Dissertation Abstracts International, Volume: 53-01, Section: B, page: 0021
Adviser: Poul M. T. Hansen
Thesis (Ph.D.)--The Ohio State University, 1991
The aim of this project was to understand how microwaves interact with functional food ingredients and to determine the effects they have on their structural and functional properties. The gelatinization patterns of microwaved and conventionally heated starch granules were observed. Although no differences in the process of gelatinization by the two methods of heating were found, it was found that in the conventionally heated samples, the smaller particles took longer to gelatinize than the larger ones. A protocol was developed to determine the particle size distribution of potato starch granules
Time-temperature profiles were obtained for dry starch powders equilibrated to a range of water activities and heated in a microwave oven. The maximum temperature achieved was not a linear function of equilibrium moisture content, but reached a maximum at a water activity level of 0.65. No gelatinization of starch granules was observed at the low water activity levels and only slight gelatinization was observed at the higher water activity levels
Dielectric data was obtained for potato starch, locust bean gum, gum arabic, carrageenan and carboxymethylcellulose. Both the dielectric constants and the loss factors increased with increasing moisture content and temperature. Locust bean gum and potato starch are neutral polysaccharides compared to the other three polysaccharides that carry considerable charge. The values predicted by model equations were not significantly different from the measured values indicating that these models could be used to predict the dielectric properties of hydrocolloids within the moisture, temperature and charge range specified earlier. Moisture was found to be the most important factor in determining the dielectric properties of the hydrocolloids
To determine the effect of microwave energy on the functional properties of hydrocolloids, a model system consisting of carrageenan-milk gels was prepared. The gels were subjected to conventional and microwave heat treatment. There was a significant difference in the microstructure of the gels heated by the two methods as observed by scanning electron microscopy. Also, there was a difference in the gel strength as measured using the Instron Universal Testing Machine. The gels that had been microwaved had greater gel strength compared to the gels that had been heated conventionally. (Abstract shortened with permission of author.)
School code: 0168
DDC
Host Item Dissertation Abstracts International 53-01B
主題 Agriculture, Food Science and Technology
Chemistry, Radiation
0359
0754
Alt Author The Ohio State University