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Studies on Preparation of Lactic Acid Sourdough Starters and Their Fermentation and Baking Properties

Author: LiuRuoShi
Tutor: HuangWeiNing
School: Jiangnan University
Course: Cereals, Oils and Vegetable Protein Engineering
Keywords: Lactic acid bacteria sourdough fermentation agent Freeze-drying Trehalose Rheological properties Biochemical properties Baking properties Flavor
CLC: TS213.2
Type: Master's thesis
Year: 2010
Downloads: 168
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Abstract

This thesis, Lactobacillus plantarum (LP) and the San Francisco Lactobacillus (LS) ordinary flour and whole wheat flour sourdough fermentation agent freeze-drying and fermentation agent corresponding Dough and biochemical properties, and to explore the sourdough fermentation technology of its baking characteristics and bread flavor. Sourdough fermentation agent four freeze-dried lactic acid bacteria were Lactobacillus plantarum the ordinary pink fermentation agent (PA), the San Francisco Lactobacillus ordinary powder fermenting agent (SA), Lactobacillus plantarum fermentation agent of whole wheat flour (PW) and the San Francisco Lactobacillus fermentation of whole wheat flour agent (SW). Lactic acid fermentation can shorten the fermentation time and cost savings, the total acidity of the whole wheat flour fermentation agent (TTA) is higher than the ordinary powder leavening agent. Trehalose has a protective effect of freeze-dried lactic acid bacteria of lactic acid bacteria in sourdough fermentation agent. Trehalose addition of acid-producing ability of lactic acid bacteria in the ordinary powder leavening agent enhancement, 10% of the added amount of the most remarkable improvement on which the survival rate of lactic acid bacteria; significantly different amounts of trehalose acid-producing ability of lactic acid bacteria in the whole wheat flour fermentation agent, 15% of the added amount of acid-producing ability of lactic acid bacteria in the fermentation agent strongest have the highest survival rate. The application Mixolab mixed experimental instrument, the dynamic rheometer F3 rheological fermentation analyzer as a reference, and chemical acidification sourdough, respectively, thermo-mechanical analysis of the lactic acid bacteria sourdough fermentation agent Dough learn dynamic rheology and fermentation rheology characteristics. The results showed that the fermentation agent added shortened dough forming time (Ordinary dough from 7.05min to 5.53 (PA), 5.08 (SA) min, whole wheat dough min from 10.72min To 10.22 (PW), 9.56 (SW), hereinafter the same) and reduce water absorption (ordinary dough from 63.1 to 61.9%, 61.3%, whole wheat dough from 65.3 to 64.6 percent, 63.8 percent) and stability (ordinary dough from 11.30min, to 10.09,9.93 min, whole wheat dough from 10.70 min to 8.52,9.45 min) to accelerate the dough weakening remain viscoelastic, improve dough expansion height (the ordinary dough from 45.0 mm to 53.1,51.7 mm, whole wheat dough from 43.6 mm to 49.1,50.2 mm) and held the gas to increase the starch gelatinization speed inhibit regenerative aging, improved cooking stability. The chemical acidification destruction stability and viscoelasticity of the dough, lower dough expansion height, fermentation endurance and held the gas. Above the ordinary high gluten dough whole wheat dough water absorption, faster enzymatic degradation, but the formation of longer, lower stability. PA more help to improve the rheological properties of high gluten dough fermentation, SW can significantly increase the flexibility of whole wheat dough. Application HPLC determination of organic acids and free amino acids in the fermentation process, analyzed the biochemical properties of lactic acid bacteria sourdough fermentation agent Dough. Lactic acid, acetic acid and amino acid as the fermentation product, the content thereof is related to the fermentation substrate and strains. Four fermentation agent TTA there is a big difference, whole wheat flour leavening agent (PW 9.31 mL, SW 11.33 mL) was significantly higher than that of ordinary powder leavening agent (PA 4.49 mL, of SA 4.96 mL), LS fermentation agent than LP fermentation agent. The content of lactic acid and acetic acid by fermentation type decisions, the homofermentative bacteria LP generates more lactic acid (PA 9.8387 g / g dry sample, PW 13.4249 g / g dry sample), Shaped fermentative bacteria LS generate more acetic acid (SA 0.4092 g / g dry sample, SW 0.5637 g / g dry sample). Whole-wheat system relatively more fermentable sugars generated more lactic acid and acetic acid, TTA value is higher, and the total amount of free amino acids in the system is also higher (PW 63.7830 mg/100g dry sample, SW 66.3295 mg/100g dry sample ). Were lower due to the dilution effect of flour and other ingredients, mixing the acidity of the sourdough and its various fermentation products content. The dough proofing increase in acidity and free amino acids, the increase in lactic acid and acetic acid content and has a strain-specific. The wholemeal still conducive to the formation of fermentation products, and higher than the non-sourdough sourdough. Hardness, moisture migration enthalpy change and volatile compounds by measuring the specific volume of the bread, to analyze the impact of the lactic acid bacteria sourdough leavening agent for bread baking characteristics and flavor. Add leavening agents can improve the specific volume and texture of the bread, to prevent moisture migration, inhibition of amylopectin retrogradation improve the baking properties of bread, and give the bread a better flavor. Higher than the total amount of volatile substances bread to add LS fermentation agent add LP fermentation agent bread. Whole wheat bread volatile matter content is higher, 3 - methyl-1 - butanol, 3 - hydroxy-2 - butanone, furfural, 3 - methyl-butyric acid and benzene, ethanol and other important flavor compounds, it The fragrance of malt fragrant, creamy and sweet almond aroma. PA and SA (LS ordinary powder leavening agent) for 5 - butyl -2 (3H) - dihydro-furanone lactone formation, making the ordinary high-gluten flour sourdough bread rich coconut and fruit-like aroma. Chemical acidification leading to the decline in quality of bread baking, flavor deterioration.

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