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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The effect of processing on the chemical composition and texture of Chinese waterchestnut, Eleocharis dulcis

Wong, Marianne Mui-Ling 28 February 1964 (has links)
In the present study, the textural changes induced in Chinese waterchestnuts by physical and chemical means were of prime concern. After being subjected to chemical and heat treatments, the corms were analyzed to relate the chemical changes with the physical changes in the corms. Chinese waterchestnuts were peeled, filled in cans with one hundred ml of various concentrations of hydrochloric acid and sodium hydroxide, and heated in the retort for one hour at 240°F (115.6°C). Distilled water was used for the control samples. Physical and chemical examinations followed, and the results of the texture measurements were compared with the chemical composition of the corms. A physical measurement of texture was obtained by using the Maryland Shear-press. The drained weights, total solids, alcohol insoluble solids, ash, total sugars, cellulose, starch, total pectins including three pectic fractions, phosphorus, calcium and potassium were determined. Measurements of pH, degrees Brix, and color intensity were made on the processed liquid. The results indicated the following conclusions: 1. Processing in both acid and alkali had a definite softening effect on the Chinese waterchestnut corm. 2. The highest correlation was obtained between texture (as measured by maximum force and total work) and cellulose in both the acid and alkali series. 3. The hydrolysis of cellulose and starch was more complete in the acid series. 4. A linear relationship existed between the pH of the acid series and texture. 5. The samples processed in acid showed more consistent trends than did the alkali processed samples. 6. There was a darkening in color as the concentration of both the acid and alkali increased. 7. The percentages of total solids and AIS showed a definite trend when compared with the texture measurements. 8. The relationship between firmness of the corms and the pectic substances in this study was a complex relationship due to the reactive nature of the pectic compounds. / Graduation date: 1964

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