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Studies on Prefermented Frozen Dietary Fiber Dough and Its Application in Steamed Bread Making

Author: HuangLiQun
Tutor: HuangWeiNing
School: Jiangnan University
Course: Cereals, Oils and Vegetable Protein Engineering
Keywords: Dietary fiber Pre- fermented frozen dough bread Transglutaminase Glycerin Response surface methodology
CLC: TS213.2
Type: Master's thesis
Year: 2010
Downloads: 81
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Abstract

In this thesis, the fermentation of dietary fiber and pre-frozen bread dough production process in the application of research include: dietary fiber and transglutaminase (TGase) Dough thermo-mechanical characteristics; dietary fiber on bread specific volume, quality institutions and the impact of whiteness, and TGase on steamed bread quality; glycerol pre-fermented frozen dough antifreeze protection research; while using response surface method for dietary fiber, TGase, glycerin, add water and pre-fermentation time on frozen 30d pre-fermented frozen dough rheology and bread quality parameters. Experimental results show that the hybrid instrument Mixolab, different amounts of dietary fiber powder (2, 5, 8%) different effects on dough water absorption, add 8% of dietary fiber powder can improve absorption of 18.75%. Dietary fiber powder can improve dough stability, but can not reduce gluten weakening degree; while TGase added (0, 0.5, 1.0%) to further improve dough stability, while also significantly reduce the absolute value of α, improve C2 value and reduce gluten weakening degrees. Dietary fiber powder added to the starch gelatinization rate decreases, while the value of C3 decreased; TGase added to gelatinization rate increases, and increase the value of C3. No dietary fiber powder and blank samples, the added dietary fiber powder will make the return values ??have a greater degree of reduction, TGase is added such that return value is increased slightly. The results show that the quality of bread cooking: dietary fiber powder to make bread specific volume decreased significantly, but the addition of TGase can improve the specific volume of bread. Containing 5% dietary fiber in the sample added TGase was 1.0%, the bread specific volume can be maintained at 2.3 mL / g. With increasing the content of dietary fiber, bread core hardness increased significantly, but the same dietary fiber content of the sample, bread core hardness with the increase of added amount of TGase was significantly decreased, while the core chewing bread same trend; dietary fiber added to bread core flexible significantly reduced, and with the addition of TGase core flexible significantly improved bread, bread cell response is also showed the same tendency. However, the addition of dietary fiber and TGase skin whiteness on bread had no significant effect. Using differential scanning calorimetry (DSC) was measured pre-fermented frozen dough dietary fiber freezable water content, the results showed that the water content of the dough can be frozen water content ratio of frozen storage period 4 weeks increased from 44.86% to 93.74%, is added glycerol fermentation of dietary fiber pre-frozen dough can be frozen water content decreased significantly compared with the blank sample; With the extension of time frozen ice melting peak temperature rise, without adding glycerol samples increased from about 0 ℃ to 6 ℃ nearby, and the added glycerol ice melting peak temperature of the sample moves to the low temperature, frozen after 4 weeks at a peak temperature of about 0 ℃. Determination of Yeast hemacytometer survival results show that under the conditions of-18oC frozen yeast survival rate, frozen four weeks after the blank sample than fresh yeast viability decreased 29.27%. The addition of glycerol frozen samples at the same number of days, the survival ratio of the yeast blank is high, and moderate decline. Response surface experiments showed that: 30d dietary fiber on frozen pre-fermented frozen dough maximum expansion height (Hm) and bread specific volume, hardness adversely affect the proofing time of the gas release curve maximum height (H'm), gas release curve retention factor (gas holdup), specific volume and hardness have a significant impact, while glycerin and TGase were right Hm, H'm and enhance the role of hematocrit. Glycerol can ease long proofing time on the gas holdup and the adverse effects of hematocrit, and its synergy with TGase can effectively improve the quality of pre-fermented frozen dough bread. Dietary fibers and pre-fermentation time were steamed skin whiteness of a significant reducing effect, while glycerin and add water also have a negative effect on whiteness. Bread hematocrit value as a response to be optimized analysis to determine the optimal formulation and process parameters: the amount of dietary fiber added 5.75%, TGase addition of 1.0%, the addition of glycerol 4% water content 61.77%, the pre-fermentation time 40 min .

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