Characterization of biopolymers: starch and soy protein

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dc.contributor.advisor Jay-lin Jane
dc.contributor.author Song, Yongxia
dc.contributor.department Food Science and Human Nutrition
dc.date 2018-08-23T17:10:23.000
dc.date.accessioned 2020-06-30T07:20:23Z
dc.date.available 2020-06-30T07:20:23Z
dc.date.copyright Sat Jan 01 00:00:00 UTC 2000
dc.date.issued 2000-01-01
dc.description.abstract <p>Two biopolymers in food system, starch and protein, were studied in structures and properties. Four different types of barley starches were isolated from barley seeds. Bimodal size distributions and A-type x-ray diffraction pattern of all four barley starches were confirmed. Barley starches displayed similar onset gelatinization temperature ranging from 55.0 to 56.5°C. Apparent and absolute amylose contents, molecular size distributions of amylose and amylopectin, amylopectin branch-chian-length distributions, and Naegeli dextrin structures of the starches were analyzed. Results showed that amylose contents (9.1% to 44.7%) and total phosphorus contents (0.022% to 0.068%) varied among normal, waxy, and high amylose barley starches. 31P-NMR analysis showed that phosphorus in barley starches was mainly from phospholipids. All the barley starch varieties had short branch chain lengths and displayed a substantially reduced proportion of chains at DP 18--21. Waxy barley (W. B. Merlin) amylopectin had the longest detectable chain length of DP 67, whereas normal barley (glacier), high amylose glacier and high amylose hull-less glacier amylopectins had the longest detectable chain length of DP 82, 79, and 78, respectively;Different soy protein isolate samples were used to study the effect of protein conditions on mechanical properties and water absorption property after compression molding process. Results showed that all the soy protein isolate samples used in this study had good processability by compression molding. But properties of molded soy protein specimens varied among soy protein samples. The specimens made from the protein isolate samples with less denaturation and pH close to isoelectric point gave better dry and wet mechanical properties and low water absorption property. Physical properties of soy protein isolate samples could affect the properties of molded specimen counterparts;Rapid viscosity analysis showed the effect of addition of soy protein on pasting properties of different starches. The viscosity profiles varied among different starches and different soy protein concentrations. Potato starch and the interaction between potato starch and soy proteins were significantly affected by salt in the mixture of starch and protein. Soy protein could form helical complex with amylose through hydrophobic interactions, which retarded the swelling of starch granules. Protein could interact with phospholipids in starch and facilitated granule swelling. Decreased pasting temperature was observed in the mixture of normal maize starch and soy proteins. Pasting temperatures of waxy maize and potato starches were increased after soy proteins were added;The three studies showed that structures of both starch and soy protein affected their properties and applications in food and non-food systems.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/rtd/12361/
dc.identifier.articleid 13360
dc.identifier.contextkey 6784502
dc.identifier.doi https://doi.org/10.31274/rtd-180813-13630
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath rtd/12361
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/65721
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/rtd/12361/r_9990487.pdf|||Fri Jan 14 19:19:29 UTC 2022
dc.subject.disciplines Agriculture
dc.subject.disciplines Food Science
dc.subject.keywords Food science and human nutrition
dc.subject.keywords Food science and technology
dc.title Characterization of biopolymers: starch and soy protein
dc.type article
dc.type.genre dissertation
dspace.entity.type Publication
relation.isOrgUnitOfPublication 4b6428c6-1fda-4a40-b375-456d49d2fb80
thesis.degree.level dissertation
thesis.degree.name Doctor of Philosophy
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