Effects Of Wheat Endogenous Lipids On The Cooking Characteristics Of Noodle

Noodle is one of the traditional foods of China, which has a wide range of consumer group.There is a little lipids in wheat flour, but which is vital to noodle properties. Separation andreconstitution is an important way to study the relationship between lipids and noodleproperties. In this study, the organic solvent and way to separate were studied. The effects offree lipids content on the textural properties and cooking characteristics of Chinese fresh andcooked noodle were investigated through separation and reconstitution of free lipids. Themechanisms of these effects were studied with the methods of scanning electron microscopyand confocal scanning laser microscopy. The main results are as follows:(1) By using soxhlet extraction method with petroleum ether as solvent to separate andrecombine the free lipids of wheat flour, influenced little on the qualities of flour, doughand noodle.(2) The springiness, cohesiveness and resilience of fresh white salt noodle were significantlyreduced with increased free lipids content (0~5%). With the increased of the free lipidscontent, the changes of cooked salt noodle hardness was not obvious. Increased free lipidscontent, cooked salt noodle springiness, cohesiveness and resilience were significantlyreduced. When the lipids content was moderate(1%~3%), the tensile properties of freshwhite salt noodle was good.(3) Fresh yellow alkali noodle hardness, springiness, cohesiveness and resilience significantlyreduced with increased content of free lipids. When the lipids content wasmoderate(1%~3%), the breaking strength of alkali noodles was the largest. With theincreased of free lipids content, fresh and cooked yellow alkali noodle breaking lengthincreased significantly.(4) With the increased of free lipids content, the cooking time, water absorption and drymatter loss of white salt noodle and yellow alkali noodle were significantly reduced. Thealkali noodle had the same discipline as the salt noodle. At the same cooking time, Withthe increased of free lipids content, the degree of gelatinization of salt noodle increased.At the same free lipids content level, the cooking time and water absorption of yellowalkali noodle both higher than white salt noodle, but for dry matter loss, the salt noodlehigher than yellow alkali noodle.(5) The results of RVA experiments showed that, increased content of free lipids led peakviscosity, trough viscosity, final viscosity and peak time of wheat flour and wheat starch were significantly reduced. The results of DSC showed that, with the increase of the freelipids content, Endothermic enthalpy of starch was reduced. These results showed thatadded free lipids could be able to speed up the rate of starch gelatinization.(6) The results of confocal scanning laser microscopy showed that, the free lipids had a samediscipline as gluten. In the picture, there were many holes. These showed free lipid indough combined with gluten and located on the surface of the net structure of gluten.(7) Analysis combination of free lipids in different the process of pressing and cooking time,the results showed: in the process of pressing, the extraction of free lipids firstly decreasedand then stabilized, which showed free lipids combined with other constituents. Theextraction of free lipids decreased with the extension of cooking time, which showed inthe process of cooking, the free lipids further combined with other constituents.(8) The results of electron microscope scanning indicated that during the process of doughcuring and press, the starch granules in the exposed area of the gluten decreased and thestructure of gluten was more uniform and closer. The amount of intact starch granules inthe noodles decreased after water swelling and rupture. For the same cooking time, theamount of intact starch granules of the noodle added more free lipids was more than thatof the noodle added less free lipids.