Study On Processing Characteristics

The article firstly determined the tensile properties, water distribution, dynamic rheological properties, microstructure, physicochemical properties and stewed noodles quality applying different salt addition, mixing process and resting process. Stewed noodles processing technology was optimized by using response surface method. The quality of stewed noodles was improved by adding appropriate proportion of wheat gluten, sodium alginate, and sodium carbonate. The main results are as follows:1. With the salt addition increasing, a more intensive crosslinkage on gluten proten microstructure was observed, and the maximum tensile force of dough increased. Adding an appropriate amount of salt, the elastic modulus(G’) and viscous modulus(G") both increased. When the salt amount reached more than 3%, the immobile water ratio and free water ratio were reduced, but the portable water ratio was increased. Within 0~5%, the content of glutenin macropolymer and the index of wet gluten kept increasing. When salt ratio reached more than 3%, the content of wet gluten and tensile distance both reduced, and the content of glutenin macropolymer remained the same level. As a conclusion, the desired quality of stewed noodles dough was obtained with the salt ratio below 3%.2. After a 10 min mixing, the tensile distance of stewed noodles dough became the largest, while the maximum tensile force was obtained at 15 min. The textural properties and sensory quality of stewed noodles declined when the mixing time was over 20 min. When mixing time was more than15 min, the disulfide bond decreased and sulfhydryl group increased. With mixing time increasing, the content of small GMP particle and H/L kept reducing significantly, but the content of large GMP particle increased. With water addition increasing, the immobile water ratio increased,while the portable water ratio decreased. It could be concluded that the hydration of gluten protein and starch was enhanced to form gluten network structure gradually.When the water addition was between 51%~53%, the best dough extensibility,textural properties and sensory quality of stewed noodles were acquired. The index of wet gluten, textural properties and sensory quality of stewed noodles decreased when the water addition exceeded 53%.3. With dough resting temperature increasing, the tensile force of dough kept decreasing gradually, and the tensile distance increased firstly then decreased. The content and index of wet gluten decreased significantly when temperature hit over35 ℃. The content of β-sheet, random coil, α-helix, and β-turn changed slightly within 20~30 ℃, while the α-helix, β-sheet content declined, the random coil andβ-turn content increased between 30~40 ℃. With an increasing dough resting temperature, the immobile water ratio and free water ratio both decreased, and the portable water radio firstly decreased then increased. The viscoelasticity modulus of dough declined when the resting temperature was above 30 ℃. The experiment results suggested that dough resting reduced the protable water ratio, while increased the ratio of immobile and free water. With mixing time increasing, the content of small GMP particle kept reducing, and the content of large GMP particle stayed increasly.From these results, it could be concluded that the quality and size of glutenin macropolymer had been re-assembled. At a time of 90 min, the disulfide bond in dough reached the highest with the lowest sulfhydryl group. The tensile force of dough declined, while the tensile distance rised with resting time increasing. When resting time was over 90 min, the tensile properties no significantly changed.4. A Box-Behnken central combination experiment was designed based on the results of single factor testments. The sensory scores of stewed noodles were used as criteria for the response surface method to systematically optimize the processing conditions. The results showed that the optimal processing conditions were as follows:water addition 51%, mixing time 10 min, salt addition 2.30%, dough resting temperature 31 ℃, and dough resting time 93 min(three times, 31 min each time).5. The three kinds of food additives were selected according to the single factor experiments. They were wheat gluten, sodium alginate, and sodium carbonate.According to the results from orthogonal experiments and comprehensive fuzzy evaluation, the best combination of three additives were: 1.0% wheat gluten, 0.1%sodium alginate, and 0.04% sodium carbonate.