機(jī)械外文翻譯文獻(xiàn)翻譯氯化鈉、混合時(shí)間及設(shè)備對(duì)面團(tuán)的熱力學(xué)特性的影響

1、機(jī)械專(zhuān)業(yè)中英文文獻(xiàn)翻譯中文 中文3258字Dough thermo-mechanical properties: influence ofsodium chloride, mixing time and equipmentA. Angioloni*, M. Dalla Rosa出處： 出處：Journal of Cereal Science 41 (2005) 327–331AbstractThermo-mechanical prope

2、rties of doughs prepared from common wheat flour were investigated under different kneading conditions and with different amounts of sodium chloride. Dynamic mechanical thermal analysis showed that high-speed mixing and

3、the addition of salt to dough slowed heat-induced reactions such as starch gelatinisation and protein coagulation. The effect of dough mixing technology was more significant than the amount of sodium chloride in modifyin

4、g dough rheological characteristics. q 2004 Elsevier Ltd. All rights reserved.Keywords: Dough; Mixing; Sodium chloride; Thermo-mechanical properties; Starch gelatinization1. IntroductionThe first step in a baking process

5、 is mixing the dough; how the mixing is performed and the ingredients are incorporated and dispersed largely determine the final quality of the baked product (Aamodt et al., 2003; Basaran and Go¨cmen, 2003). The pro

6、duction of wheat dough is a process in which raw materials (mainly flour, water, salt and yeast) are mixed and subjected to a large range of strain situations. Dough is a complex mixture of starch, protein, fat and salt.

7、 Mixing has three important functions: (i) it blends the ingredients into a macroscopically homogeneous mass, (ii) it develops the dough into a three-dimensional viscoelastic structure with gas-retaining properties and (

8、iii) it incorporates air which will form nuclei for gas bubbles that grow during dough fermentation (Bloksma, 1990; Collado and Leyn, 2000; Dobraszczyk and Morgenstern, 2003; Hoseney and Rogers, 1990; Naeem et al., 2002)

9、. Both mixing intensity and mixing energy must be above a minimum critical level to develop the dough properly, the level varying with flour and mixer type (Kilborn and Tipples, 1972; MacRitchie, 1986; Skeggs, 1985; Zhen

10、g et al., 2000). The time required for optimum dough development is positively correlated with the polymeric protein composition and the balance between protein polymers and monomers (Dobraszczyk and Morgenstern, 2003; M

11、acRitchie, 1992; Millar, 2004). Rheological properties change during every stage of the dough making process; stress conditions are high when the dough is mixed in high-speed mixers, to become an elastic and coherent mas

12、s. Mixing speed and energy (work input) must be higher than a certain value to develop the gluten network and to produce a suitable breadmaking dough. On the other hand, an optimal mixing time has been related to optimum

13、 breadmaking performance which varies depending on mixer type and ingredients (Dobraszczyk and Morgenstern, 2003; Mani et al., 1992). For example, kneading doughs to reach optimum development using elongational flow in s

14、heeting, required only 10–15% of the energy generally 機(jī)械專(zhuān)業(yè)中英文文獻(xiàn)翻譯until the thickness of sample was 2 mm and excess was trimmed off. The exposed surface was covered with a thin layer of mineral oil to prevent moisture lo

15、ss during testing. The sample was rested another 15 min in the rheometer, before each measurement, allowing relaxation of stresses induced during sample loading to relax. All measurements were performed at a heating rat

16、e of 0.8 8C/min at fixed frequency of 1 Hz with the oscillation amplitude small enough to ensure linear viscoelasticity. The data are reported as means of measurements made on three samples, where each sample was obtaine

17、d from a separately prepared batch of dough for each formulation and for the different mixers used. Significant differences in storage modulus (G0) at 1Hz were determined by Least Significant Difference analysis with P%0

18、.05. All statistical analyses were performed with the Stat Soft Version 6.3. Results and discussion3.1. Flour chemical and physical propertiesThe chemical composition and rheological properties of the flour are shown in

19、Table 2. Analysis of Alveograph data categorises the flour used as weak, and as seen by the P/L ratio, the gluten is richer in gliadins than in glutenins The resistance of a gluten dough to extension decreases and extens