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Preparation And Properties Of Complexes Between Lipids And Waxy Rice Starch

Posted on:2014-06-25Degree:MasterType:Thesis
Country:ChinaCandidate:D ChenFull Text:PDF
GTID:2251330425952810Subject:Food Science
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As one of the rice varieties, waxy rice is the primary raw material of ricedumpling which is one of the traditional Chinese food. The waxy rice starch havingmore than95%amylopectin shows weak retrogradation, anti-staling and goodfreeze-thaw stability, which makes it suitable for frozen and refrigerated food. Thestarch molecules curl and form helical complexes with lipids under the impact ofintramolecular hydrogen bond. Starch-lipid complexes affect the solubility, swellingcapacity, rheological property, gelatinization and retrogradation characteristics of thestarch.It was studied in this dissertation how to prepare the complexes formed by waxyrice starch with palmitic and oleic acid. Single factor and orthogonal experimentswere utilized to determine the optimum conditions for preparing complexes.Meanwhile, the thermal properties, gelatinization and retrogradation behaviour andfreeze-thaw stability of complexes were investigated by Rapid Viscosity Analyzer,Differential Scanning Calorimeter. Finally, palmitic acid and oleic acid were added tomake waxy rice flour dough and the effects of these two fatty acids on the texture ofwaxy rice flour dough were studied..The results of preparing complexes between waxy rice starch and lipids showedthat impacts on complex index (CI) of the complexes were as follows: fatty acidsamount> stirring time> reaction temperature. The optimal conditions of preparingcomplexes formed by palmitic acid and waxy rice starch were that palmitic acid0.5%,reaction temperature80℃, stirring time35min. As for oleic acid, the conditions wereoleic acid0.7%, reaction temperature80℃, stirring time25min.By analyzing the changes of properties between native starch and complexes, itcan be drawn the complexes had lower peak viscosity, higher final viscosity and lowerbreakdown than native starch. The DSC showed that the values of onset temperature,peak temperature and gelatinization enthalpy of complexes were all less than native starch, and the endothermic enthalpy of complexes formed by palmitic acid was lessthan those formed by oleic acid. The retrogradation enthalpy and retrogradation rateof the complexes stored for14days was far lower than native starch, which indicatedpalmitic acid and oleic acid could inhibit the retrogradation of waxy rice starch. Thefreeze-thaw stability of waxy rice starch was improved by the addition of palmiticacid and oleic acid, and separate water’s velocity of different groups was nativestarch> the complexes with oleic acid> the complexes with palmitic acid.Results of pre-cooked waxy rice flour dough storage experiment showed that thehardness of waxy rice flour dough increased, springiness decreased and gummiesincreased with prolonging the storage time. Compared with control, the waxy riceflour dough which was added with palmitic acid and oleic acid showed lowerhardness, lower gumminess and higher springiness. The addition of0.7%palmiticacid significantly inhibit aging of waxy rice flour dough. The waxy dough added with0.7%palmitic acid had lowest hardness and gumminess and highest springiness whenstored for14days.
Keywords/Search Tags:waxy rice starch, fatty acids, complex index, pasting properties, retrogradation properties, waxy rice flour dough
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