Structural-functionality changes of corn starches induced by gamma irradiation

Chung, Kok Heung (2015) Structural-functionality changes of corn starches induced by gamma irradiation. Masters thesis, Universiti Malaysia Sabah.

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Abstract

The effects of gamma irradiation on the physicochemical and morphological properties of starch samples were investigated. Corn starches with different amylose content (waxy, normal, Hylon V, and Hylon VII) were treated with five doses of gamma irradiation (1 kGy, 5 kGy, 10 kGy, 25 kGy, and 50 kGy). Waxy samples showed an increase of amylose-like fractions when irradiated at 10 kGy. The reduction in apparent amylose content increased with amylose content when underwent irradiation at 25 and 50 kGy. The more drastic decrease in pH value and increase in carboxyl content were observed on Hylon V and VII samples indicated that starches with higher amylose content marked greater susceptibility towards oxidation effect of increasing radiation intensity. Low amylose starches lost their pasting ability when irradiated at 25 kGy and 50 kGy. Results from thermal behavior and pasting profile suggested that lower level of cross-linking effect occurred in Hylon VII samples irradiated at 5 kGy. Severe reduction in pasting properties, gelatinization temperatures and relative crystallinity with increasing irradiation intensity revealed that waxy samples were affected more by gamma irradiation; this also indicated amylopectin was the starch fraction most affected by gamma irradiation. Alteration level was portrayed differently when different kind of physicochemical properties were investigated, in which the pasting properties and crystallinity of starches were more immensely influenced by gamma irradiation while thermal behavior was less affected. Despite the irradiation level, the morphology and crystal pattern of starch granules were found remain unchanged by irradiation.

Item Type:	Thesis (Masters)
Keyword:	Corn starches, Gamma irradiation, Physicochemical and morphological properties
Subjects:	T Technology > TP Chemical technology > TP1-1185 Chemical technology > TP248.13-248.65 Biotechnology
Department:	INSTITUTE > Biotechnology Research Institute (BRI)
Depositing User:	DG MASNIAH AHMAD -
Date Deposited:	16 Aug 2024 14:57
Last Modified:	16 Aug 2024 14:57
URI:	https://eprints.ums.edu.my/id/eprint/40598

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