Fermentation process types

Rheological properties, as well as acidification and flavour development, are important parameters in controlling fermentation process. Types of microorganisms, metabolic activity, and time-dependent development of pH levels have an effect on the final rheological properties. 

Careful records must be kept to enable verification of compHance. Each lot of wine must be traceable back to the grapes and vineyard. Tanks must be carefully gauged and the capacities recorded on them. If the wine is to be labeled "estate botded," not only must the wine be fermented, processed, and bottled by the state winery at thein Hsted address, but the vineyard must also be owned or controlled by that winery. Other label terrninology, subject to some further intricacies, are "produced," ie, fermented 75% or made into a different class of wine "prepared," "vinted," or "cellared," ie, subjected to ceUar processing or aging without changing the class of wine "blended," ie, combined at the stated address, wines (probably purchased) of the same class and type and "botded" or "packed" by the stated winery. 

Lactic acid-producing bacteria associated with fermented dairy products have been found to produce antibiotic-like compounds caUed bacteriocins. Concentrations of these natural antibiotics can be added to refrigerated foods in the form of an extract of the fermentation process to help prevent microbial spoilage. Other natural antibiotics are produced by Penicillium wqueforti the mold associated with Roquefort and blue cheese, and by Propionibacterium sp., which produce propionic acid and are associated with Swiss-type cheeses (3). 

Figure 3.1 illustrates the main patterns for batch fermentation process kinetics for type 1,2 and 3 processes. 

Currently dtric add is still manufactured almost entirely using A. niger growing on carbohydrate substrates. Three types of fermentation process have been used ... 

The power per unit volume is constant. From power consumptions in a bench-scale bioreactor, the necessary agitation rate is calculated for the scale up ratio, using Equation (13.2.1). The choice of criterion is dependent on what type of fermentation process has been studied. The following equation expresses relations for the impeller size and agitation rate in small and large bioreactors. 

Normally, fermentation processes can be classified depending on the objective of study. For example, in terms of products fermentation is divided into 4 types, namely, microbial cell, microbial enzyme, microbial metabolite and transformation process. If considering due to its contaminating conditions, it will be classified into 3 types septic, semi-septic and aseptic fermentation. However, in general, the fermentation processed are classified into 3 types as follows. 

Fed-batch fermentation process is a production technique between batch and continuous fermentation. A proper medium feed rate is required to add sequentially into the fermentor during the process and the product is harvested at the end of fermentation just like a batch type. 

This chapter has compiled and evaluated information on the methylxanthine composition of cocoa and various chocolate foods and beverages, as well as the consumption pattern for these commodities. Cacao is the major natural source of the xanthine base theobromine. Small amounts of caffeine are present in the bean along with trace amounts of theophylline. Numerous factors, including varietal type and fermentation process, influence the methylxanthine content of beans. 

Recently, PHAs based on fatty acids have been crosslinked. By varying the type of fatty acid in the fermentation process, the type and amount of double bonds in the pendant chains was easily adjusted (Table 6). PHA based on coconut... 

Many factors affect the production of biogenic amines in fermented meats, including the natural microflora present and their ability to decarboxylate, manufacturing processes, type and quality of meat, and the length of maturation (Shalaby, 1995). 

The product of this metabolic sequence, pyruvate, is a metabolite of caitral importance. Its fate depends upon the conditions within a cell and upon the type of cell. When oxygen is plentiful pyruvate is usually converted to acetyl-coenzyme A, but under anaerobic conditions it may be reduced by NADH + H+ to the alcohol lactic acid (Fig. 10-3, step h). This reduction exactly balances the previous oxidation step, that is, the oxidation of glycer-aldehyde 3-phosphate to 3-phospho-glycerate (steps a and b). With a balanced sequence of an oxidation reaction, followed by a reduction reaction, glucose can be converted to lactate in the absence of oxygen, a fermentation process. The lactic acid fermentation occurs not only in certain bacteria but also in our own muscles under conditions of extremely vigorous exercise. It also occurs continuously in some tissues, e.g., the transparent lens and cornea of the eye. 

There are many applications where it is necessary to monitor very low rates of flow (e.g. addition of mercaptans to natural gas in the gas industry or of anti-foaming agents to fermentation processes in the pharmaceutical industry). A low flow is considered to be of the order of 100 mm /s and an ultra-low flow of around 0.1 mm3/s for both liquids and gases. Table 6.2 includes commonly accepted minimum measurable rates of flow for types of flowmeter normally employed for this purpose02 . 

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