| In this research, it is aimed to study on the quality improvement of instant rice noodles (IRNS) and the development of nutrition fortification IRNS with the addition of whole egg powder. And conclusions are obtained as follows:1. The changes of rice properties were studied. The results indicated that the whole processes could be divided into the following three stages:higher E1(the first spring model) resulted in higher initial elastic; higher η1(the dashpot model) revealed higher viscosity and longer relaxation time τ1;lower E2and lower η2(E2and η2were the second spring model and dashpot model in extrusion gel) resulted in smaller and slower changes in the later compressive gel, and shorter relaxation time τ2,which was a key factor in the quality control and evaluation of IRNS, using model of Burger to fit curve of stress-relaxation teat of gelatinization after extrusion and curve of creep. The texture of rice gelatinization after extrusion was a3D network formed by amylase winding with each other, in which amylopectin was dispersed. Since protein existing in the network had changed the flow state of water and created lower T22and higher T23, elastic of the system reduced. And in the same way, hardness of starch gelatinization decreased and viscosity raised because of fat. The results showed that the average shear stress, rehydration and cooking loss of boiling were key factors in the quality control and evaluation of instant rice noodles. Therefore, equations obtained on the basis of interaction effect between properties of rice and quality of IRNS could provide a significant reference for selection of raw materials.2. Twenty groups of raw materials (rice or starch) combinations were designed by means of a trial of mixture design. And the comprehensive evaluation of textural properties, cooking properties, sensory properties and color value of IRNS were discussed by undimensionalization and principal component analysis. This methodology is not only scientific and reasonable, but also rapid and effective to obtain Ztextural, Zcooking, Zsensory and Wwhiteness·Based on analysis of4integrated quality independently, D-optimization design was used to optimize the response values in accordance with all expectation, and the optimum combinations of Xingye, Fuchang, Jiufeng, and Yizhixiu were41.43%,8.70%,29.47%,20.40%, respectively. And the optimum combinations of corn starch, potato starch and tapioca starch were5.26%,9.84%,10.00%, respectively. The "Multiple-Target Evaluating Hierarchy" of food and the methodology of establishing the relation between raw material and integrated quality could be applied to comprehensive evaluation of food quality and obtaining optimum formulation of food processing. 3. The study proved that common additives had different effects on special flour and the result revealed that (1) When the content of molecule distilling monoglycerdes was below0.3%, strengthening of the motion of gelatinized starch in gel leads to breakage of its structure. While the content was above0.3%, the system destroyed by emulsifiers was able to recover or form a new structure. Besides, molecule distilling monoglycerdes played an important role in decreasing viscosity of gel.(2) Special flour could not react with guar gum, unless it was added up to a right concentration. When the content of guar gum was below0.3%, the structure of system was supported by a network made of pasting special flour, at this time food hydrocolloids didn’t work. But when it was above0.3%, special flour and guar gum mutually combinated, and the rest of guar gum produced a new different network.(3) The influence of Oligosaccharides and salt on special flour gel was the result of the multiple effects, but it was not obvious in this test.4. The Plackett-Burman design, the steepest ascent design and central composite design were applied to study composite quality improvers. It was concluded that the positive factors on the quality of IRNS were emulsifiers sucrose: fatty acid ester and soy lecithin; food hydrocolloids:xanthan gum and konjak gum; oligosaccharides and salts:β-cyclodextrin and sodium bicarbonate. The optimum formulation of quality improver of IRNS was selected through response surface analysis:xanthan gum, konjak gum, sucrose fatty acid ester, soy lecithin, β-cyclodextrin and sodium bicarbonate are respectively0.30%,0.30%,0.11%,0.37%,0.19%,0.56%. From photomicrography, it could be concluded that although small bumps still existed at the surface of IRNS with the addition of the quality improver, yet interface relaxation role triggered by these bumps and adhesion of two surface contact could not change the overall smooth of IRNS.5. Single-factor and Box-Behnken design were used to develop a new nutrition fortification IRNS. The optimum formulation:whole egg powder content24.05g/Kg, TG-M content3.15g/Kg and reaction time34.31min. Vitro starch and protein digestion ratio of fortification IRNS, in which the content of starch digestion was56.89%, the content of soluble protein was54.12%, and the content of necessary amino acids in enzymatic hydrolysate was32.58mg/mL, were higher than normal IRNS. Whole egg powder improved the flavor of IRNS, especially reduced the content of alcohols and increased the variety and content of hydrocarbons... |
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