| Author | Sorada Yoenyongbuddhagal |
| Call Number | AIT Thesis no.AE-96-14 |
| Subject(s) | Frozen foods industry
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of
Science |
| Publisher | Asian Institute of Technology |
| Abstract | This experiment was conducted to study the effects of three starch modification methods: cross-linking, hydroxypropylation and double modification, on various functional properties of waxy rice (11 % amylose content) and normal rice (31 % amylose content) starches in order to select the best method suitable for starch to be used in frozen products. The results showed that all methods did not change the color of the modified starches while the appearance of starch granules did not deviate from their native starches. The swelling power and solubility of waxy rice starches were higher than those of normal rice starches. Cross-linking reduced swelling power and solubility while hydroxypropylation and double modification increased the values for these parameters. Using a Rapid Visco Analyzer, waxy rice starches were found to have lower gelatinization temperature and require shorter time to attain peak viscosity but with higher peak viscosity value compared to normal rice starches. Cross-linking caused higher gelatinization temperature and longer time to reach the peak whereas hydroxypropylation and double modification yielded the opposite. All modification methods increased the peak viscosity. Waxy rice starches were more sensitive to heat than normal starches but their paste were more transparent than normal rice starches. Only cross linking improved heat and mechanical stability while both hydroxypropylation and double modification enhanced transparency and freeze-thaw stability. Both modified and native starches were used to make frozen strawberry pie fillings and stored for two weeks after which transparency and syneresis were examined by sensory evaluation. After thawing, fillings made from native, hydroxypropylated and double modified waxy rice starches were found to be very transparent while that from cross-linked waxy rice starch had lower transparency. The fillings from the other methods showed opacity. Moreover, no filling showed syneresis except that made from native waxy rice starch. From the results, it can be concluded that hydroxypropylated waxy rice starch is best suited for making frozen products since it showed acceptable overall properties. Its paste is very transparent and can be stored for 6 months in the frozen storage with minimal syneresis. |
| Year | 1996 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Agricultural and Food Engineering (AE) |
| Chairperson(s) | Athapol Noomhorm; |
| Examination Committee(s) | Jindal, Vinod Kumar;Vincent, Jean-Claude;Rakshit, Sudip Kumar; |
| Scholarship Donor(s) | Danish International Department Agency (DANIDA); |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 1996 |