Study On Relation Between Fermented Volume Of Dough And Temperature And Time

The full-automatic small-scale family using bread machine has the followingproblems: the fermented procedure belongs to nation-state and fast fermentation.What we called making beforehand can only be ahead of 13 hours, it only delaystime to adjust the flour, but the fermentation time is still 2 hours. This kind offermentation has determined the bread that made by this kind of bread machineshad bad sensory quality, lack of incense that the bread should have and easy toaging. The key to solve this problem is to confirm the relation between fermentedvolume and temperature and time respectively during fermentation, and toestablish the fermentation procedure of different time and temperature. The majorpurposes of this research are to determine the relation between fermented volumeand temperature and time respectively, to confirm the parameters of fermentationand to provide theoretical foundation for designing the new type small-scalefamily use bread machine of full-automatic.The paper adopted the domestic high strength flour as the major materials,studied the factors that had influence on fermented volume of dough, confirmedthe parameters of prescription that can make dough's fermented volume largest,measured the fermented volume of bread made by this prescription but withdifferent fermented times and temperatures, Eventually determined the influencesof time on dough's fermented volume, found out corresponding regressionequation between fermented volume and temperature and time. The major workand conclusions were as follows:1. The object of all the experiments in this paper was domestic high strengthflour, the prescription has been improved and verified by orthogonal experimentaccording to the prescription that has been offered by American gain chemicalassociation. Referencing concerning theory, the prescription that could make thelargest dough volume has been found.2. The relevant parameters of adjusting powder has been determined based onthe best prescription, the weight of flour was determined 1.2kg, and the relevantparameters have of adjusting powder machine have been determined based on it.3. According to the prescription which has been determined above, the doughvolume was measured every fifteen minutes from 15℃to 54℃, and the data hasbeen recorded. The time and temperature that made the largest dough volume havebeen determined through handling and analyzing experiment data.4. The tendency of dough volume changed with the temperature and time:a. Within 0-5 hours, the dough volume increased rapidly after fermentingduring 15℃-30℃, increased to the biggest value gradually, and then decreasedslowly. Along with the increase of temperature, the increasing of dough volumeaccelerated, and the time used to get the largest value has shortened obviously.While the temperature reached 31℃, the dough volume got the largest value in120 minutes. After the biggest value, the dough volume started decreasing slowly,but the changes speed of volume was not great.b. While the temperature were among 31℃-54℃,the increase of the doughvolume accelerated along with the increase of temperature before the doughvolume has got the largest value, and the time used to get the largest volume hasshortened obviously. The decrease of the dough volume accelerated after thebiggest value. Along with the increase of temperature, the decreasing speed ofvolume increased.c. While the temperature was from 30℃to 33℃, from the curve of doughvolume and time we can find, the dough volume can reach its peak, and the scopeof time with larger dough volume was also great. Then the temperature scope from30℃to 33℃was most suit to ferment.5. Based on regression model of single factors, the relation between differenttime and volume with the same temperature has been analyzed using the housemodel and quadratic curve model. The fitting rate of house model was all above0.95, the fitting rate of quadratic curve could reach above 0.95 from 15℃to 18℃,while in other temperatures, the fitting rates were all below 0.95 and the most wereabout 0.7. It has showed that the relation between fermented time and volume wasfit the house model, therefore, the house model was chosen finally.6. The coefficient table has been got through summarizing the coefficient ofhouse model among 15℃-54℃. The table could be used to guide the productionand to be the parameter to design bread machine.7. The change rate of dough volume in 25℃, 30℃, 35℃has been researchedbased on house model, the volume change of dough could be divided into 4 stages:a. The volume change rate of dough was the largest within 0-5 hours, and thevolume increase of dough was most rapid;b. The volume change rate reduced gradually along with the increase of time,the increase of dough volume correspondingly slowed down. The volume changerate reduced to zero in about 2 hours, the volume of dough didn't increased anymore, and the fermented volume of dough reached the largest value. The doughwas most fit to roast 20 minutes before the largest volume has been reached, andthe roast quality was easy to be the best.c. The volume change rate became small slowly along with the continueincrease of time, and even reduced to below zero. Then the volume of doughstarted reducing, and the dough began to sink down, at this time it wasn't fit toroast.d. The volume change rate increased lightly with the continue increase oftime, but still below zero, and the volume of dough continued reducing slowly.8. The volume change rate of unit time in 25℃, 30℃, 35℃has beenresearched based on house model, the conclusion has been shown as following:a. In the first 5 hours, the volume change rate of unit time was below zero inthe beginning, along with the increase of time, the volume change rate of unit timeincreased rapidly, the volume of dough kept increasing.b. With the continue increase of time, the volume change rate of unit timeincreased slowly, and increased to zero gradually; the volume change rate reducedslowly, and reduced to zero and to below zero. The volume of dough reached itsbiggest value while the volume change rate was zero, and the volume becamesmall while the volume change rate was below zero, at this time, the dough sankdown.c. With the continue increase of time, the volume change rate of unit timeincreased slowly and even became above zero. The volume change rate increasedslowly, but still below zero, and the volume of fermented dough continueddecreasing slowly.9. Quadric rotational regression and BP neural network have been usedrespectively to study the relation among time, temperature and dough's fermentedvolume nearby the biggest volume value. The regression model of temperature,time and volume has been established by using quadric rotational regression. Afterfitting inspect, the regression equation has been proved reliable.