Alcoholic fermentation process

A new method for the preparation of soy sauce has been developed. The new scaled-up method divides the moromi process into two processes autolysis and fermentation. Because of the utilization of high temperatures, the new process permits the production of a NaCl free autolyzate from koji. Division of the fermentation process into two separated processes permit better control of lactic acid fermentation and alcohol fermentation processed which used to require great skill. The new scale-up procedure for soy sauce production yields a product in half the time required by the traditional (conventional) method and still produces a soy sauce with high levels of the desirable Bavor component, glutamic acid. Utilization of this protocol by the soy sauce producing industry should have significant economic impact to bo producers and consumers. 

S. Elnashaie, G. Ibrahim, Heterogeneous Modeling for the Alcoholic Fermentation Process, Applied Biochemistry and Biotechnology, 19(1), 71-101, 1988... 

A software sensor for on-line determination of substrate was developed based on a model for fed-batch alcoholic fermentation process and on-line measured signals of ethanol, biomass, and feed flow. The ethanol and biomass signals were obtained using a colorimetric biosensor and an optical sensor developed in previous works that permitted determination of ethanol at a concentration of 0-40 g/L and biomass of 0-60 g/L. The volume in the fermentor could be continuously calculated using the total measured signal of the feed flow. The results obtained show that the model used is adequate for the proposed software sensor and determines continuously the substrate concentration with efficiency and security during the fermentation process. 

The control of a fed-batch alcoholic fermentation process can be obtained by controlling the substrate concentration in the medium by manipulation of the feed flow. The fermentation process presents complicated kinetic mechanisms. In addition, there is the absence of accurate and reliable mathematical models as well as the difficulty of obtaining direct measurements of the process variables owing to a lack of appropriate on-line analyzers and sensors. Control systems are formed by a set of instruments and control mechanisms connected through electrical signals in the... 

To simplify study of the fed-batch alcoholic fermentation process and with the purpose of regulating the substrate concentration in the fermentation medium, the following assumptions were made (1) the substrate concentration in the feed is constant and (2) the volume change in the fermentor is a function of feed flow. 

Evaluation of Optimization Techniques for an Extractive Alcoholic Fermentation Process... 

Development of serum-free medium has great value for large-scale biopesticide production. The latest formulations are serum-free, such as SF900II (GIBCO /Invitrogen) and EX-CELL (JRH Biosciences). Cell culture medium supplementation using yeast extract (usually from alcoholic fermentation processes), milk, or soy protein concentrates, can also be an alternative to decrease cell culture medium costs (more details can be found in Chapter 5). 

Tibayrenc, R, Preziosi-Belloy, L., Ghommidh, C. (2011). On-line monitoring of dielectiical properties of yeast cells during astress-model alcoholic fermentation. Process Biochemistry, 46, 193-201. 

The production of acetaldehyde and ethanol also starts to increase for all four cultivars during anaerobic conditions, showing that the alcoholic fermentation process replaces the aerobic respiration. All four apples present the same dynamic behavior for these compounds. At the end of the anaerobic treatment, similar fermentation rates were observed for Elstar, Granny Smith, and Jonagold, while Pink Lady produced the lowest amount of ethanol. When reexposed to oxygen, all cultivars except Pink Lady showed a clear postanaerobic acetal-... 

Background on the Problems Associated with the Heterogeneous Modeling of Alcoholic Fermentation Processes... 

A DISTRIBUTED PARAMETER DIFFUSION-REACTION MODEL FOR THE ALCOHOLIC FERMENTATION PROCESS... 

The following is an example for the development of a distributed parameter model for the yeast floe in the alcoholic fermentation process. The model takes into consideration the external mass transfer resistances, the mass transfer resistance through the cellular membrane, and the diffusion resistances inside the floe. The two-point boundary-value differential equations for the membrane are manipulated analytically, whereas the nonlinear two-point boundary-value dilferential equations of diffusion and reaction inside... 

The alcoholic fermentation process is quite a complex process and involves the following main processes. 

The dispute in the literature regarding the diffusion of ethanol has been discussed by Elnashaie and Ibrahim [4]. The slightly more detailed diffusion reaction model for the alcoholic fermentation process presented in this section of the book will help to throw more light on this dispute than the model used by Elnashaie and Ibrahim [4]. However, we are certainly still quite far from a completely rigorous representation of this rather complex diffusion-reaction problem. 

Elnashaie, S. S. E. H. and Ibrahim, G. A distributed parameter diffusion reaction model for the alcoholic fermentation process. Appl. Biochemi. Biotechnol. 30(3), 339-358, 1991. 

The main alcohol fermentation is started by moving yeast starter and adding water, steamed rice, and rice malt to a larger tank. The temperature and other factors of the alcohol fermentation process are measured and adjusted to create the flavor and taste profiles of the sake product. After the fermentation, the mash is pressed with a Alter press to remove the white lees and unfermented solids, and clear sake is obtained. 

Finally, certain membrane proteins act as cellular specific receptors. They permit the yeast to react to various external stimuli such as sexual hormones or changes in the concentration of external nutrients. The activation of these membrane proteins triggers the liberation of compounds such as cyclic adenosine monophosphate (cAMP) in the cytoplasm. These compounds serve as secondary messengers which set off other intercellular reactions. The consequences of these cellular mechanisms in the alcoholic fermentation process merit further study. 

Another approach consists of creating a model of the alcoholic fermentation process. Different calculations concerning time, temperature, and alcohol and sugar concentrations are used to predict fermentation behavior—especially the risk of a stuck fermentation (Bov e et al., 1990). In this way, the need and moment of a certain operation (especially temperature control) could be anticipated. 

More specifically, the preliminary development of yeasts, lactic bacteria or Botrytis cinerea can hinder the alcoholic fermentation process. In the case of alcoholic fermentation difficulties, bacterial growth and malolactic fermentation exacerbate these difficulties. Stuck fermentations often result (Sections 3.8.1 6.4.1). 

The general mechanisms that link the nitrogen and oxygen needs of yeasts during the alcoholic fermentation process (Sections 2.4.2, 3.4.2 and 3.5.2), explain the advisability of the addition of ammonium salts and the necessity of aeration during dry white winemaking. 

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