In vitro digestibility of starch in sorghum differing in endosperm hardness and flour particle size

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dc.contributor.author Xu, Xiaoli
dc.date.accessioned 2008-08-19T12:46:09Z
dc.date.available 2008-08-19T12:46:09Z
dc.date.issued 2008-08-19T12:46:09Z
dc.identifier.uri http://hdl.handle.net/2097/950
dc.description.abstract In vitro digestibility of starch in sorghum grains differing in endosperm hardness and flour particle size was assayed by an Englyst resistant starch (RS) method. The starch digestibility increased as the particle size of flour decreased, but no significant difference in starch digestibility was observed among sorghum flours milled from grains with different hardness. To further understand the digestion of starch in sorghum, the effects of protein on starch digestion and amylose content in starch were determined. pH value was a factor affecting protein digestion since protein digestibility was higher at pH 2.0 than that at pH 1.3. Protein hydrolysis increased with time of pepsin treatment, leading to an increased starch digestion. RS content was 10.61-29.54% in native sorghum flours and 8.47-26.28% in isolated sorghum starch. The amounts of [Gamma]-kafirins extracted increased with time of pepsin treatment while [Alpha]- and [Beta]-kafirins decreased. The starch in sorghum flour with median hardness had a higher amylose content (23.9%) than the starch in hard and soft flours (~21%), which gave lower starch digestibility. Protein digestibility decreased after cooking while starch digestibility increased. Sulfhydryl groups decreased after cooking, indicating that disulfide bonds formed between protein molecules and may have formed a barrier for enzymes to access and digest starch. Confocal laser scanning microscopy (CLSM) showed that the protein matrix was less evident after pepsin treatment. As a result, starch digestion increased after protein matrix was removed. en
dc.language.iso en_US en
dc.publisher Kansas State University en
dc.subject sorghum en
dc.subject starch en
dc.subject digestion en
dc.subject in vitro en
dc.title In vitro digestibility of starch in sorghum differing in endosperm hardness and flour particle size en
dc.type Thesis en
dc.description.degree Master of Science en
dc.description.level Masters en
dc.description.department Department of Grain Science and Industry en
dc.description.advisor Yong Cheng Shi en
dc.subject.umi Agriculture, Food Science and Technology (0359) en
dc.subject.umi Chemistry, Biochemistry (0487) en
dc.date.published 2008 en
dc.date.graduationmonth August en


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