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The objective of this study was to determine the effects of hydrocolloids in dough (xanthan 0.02%, 0.06%, and 0.1%; kappa-carrageenan and carboxymethylcellulose 0.2%, 0.6%, and 1.0%) and duration of frozen storage on the quality of finished bakery product. Doughs were prepared with different concentrations of gums, stored at -18 degrees C and analyzed after 0, 7, 14, and 30 d for fermentation activity of yeast and rising time of dough. At the end of each frozen storage interval, bread was prepared and characterized for specific volume, crumb firmness, and crumb structure. The addition of the gums had significant effects on dough performance and quality of the final product. Gums at all tested concentrations reduced fermentation activity of yeast and prolonged the rising time of dough, which was similar to the effects of frozen storage. However, specific volume of bread for the control sample significantly decreased on the 30th d of frozen storage. Addition of hydrocolloids resulted in higher specific volume of loaves compared to the specific volume of control sample loaves. With the increase of the duration of frozen storage the specific volume of bread decreases in all analyzed samples. This decrease is less in the samples with hydrocolloids compared to the decrease in the control sample. The addition of 0.1% xanthan accomplished the same or higher values for specific fermentation activity, specific volume, and penetrometric's number compared to the values accomplished by the addition of 1% carboxymethylcellulose and kappa-carrageenan, respectively.

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Wine industry generates large volumes of wastewaters resulting from numerous cleaning operations that occur during the different stages of winemaking. Disposal of these effluents in the environment causes huge problems due to their high organic and inorganic load and seasonal variability. The bioconversion of winery wastewaters in valuable product, such as xanthan, is an important alternative to overcome environmental problems. In this research, the possibility of xanthan production using Xanthomonas campestris on blended wastewaters from different stages of white and rose wine production with initial sugar content of 50 g/L was investigated. In addition to the media parameters (content of sugars, total and assimilable nitrogen, phosphorus, total dissolved salts and apparent viscosity), raw xanthan yield and degree of sugar conversion into product were determined in order to examine the success of xanthan biosynthesis. In applied experimental conditions, xanthan yield of 20.92 and 30.64 g/L and sugar conversion into product of 40.23 and 60.73% were achieved on wastewaters from white and rose wine production, respectively. The results of these experiments suggest that winery wastewaters, after additional optimization of the process in terms of the substrate composition and the cultivation conditions, may be a suitable raw material for industrial xanthan production.

a b s t r a c tThe aim of this work was to model and predict the process of bioethanol production from intermediates and byproduct of sugar beet processing by applying artificial neural networks. Prediction of one substrate fermentation by neural networks had the same input variables (fermentation time and starting sugar content) and one output value (ethanol content, yeast cell number or sugar content). Results showed that a good prediction model could be obtained by networks with single hidden layer. The neural network configuration that gave the best prediction for raw or thin juice fermentation was one with 8 neurons in hidden layer for all observed outputs. On the other side, the optimal number of neurons in hidden layer was found to be 9 and 10 for thick juice and molasses, respectively. Further, all substrates data were merged, which led to introducing an additional input (substrate type) and defining all outputs optimal network architecture to 3-12-1. From the results the conclusion was that artificial neural networks are a good prediction tool for the selected network outputs. Also, these predictive capabilities allowed the application of the Garson's equation for estimating the contribution of selected process parameters on the defined outputs with satisfactory accuracy.