Concentrating crude protein product

The next phase of downstream processing usually entails concentration of the crude protein product. This yields smaller product volumes, which are more convenient to work with and can subsequently be processed with greater speed. Concentration may be achieved by inducing... 

The production of CDs via enzymatic reaction with starch has been recently reviewed (i 7). CGTase is an extracellular protein and is usually isolated as a crude mixture from the medium. This crude protein is used directly for industrial fermentations. The basic process involves standard enz3miatic fermentation, with careful attention to reaction temperature. All three CDs and some Unear oligosaccharides are normally produced. Yields are highly dependent on the source of starch substrate. Potato starch is normally used or an extract of potato starch is often added to other starches 18-19), The potato starch component(s) responsible for stimulating CD formation have not been determined. Low starch concentrations (5%-10%) are normally used industrially. Published yields are in the 50% - 80% conversion range. 

Methods to estimate digestibility which avoid the necessity for fistulation include gas production from feeds incubated with faecal inoculums using an automatic pressure evaluation system, and various digestion marker methods (see below). The concentration of marker in the feed and faeces may be used to calculate the apparent digestibility of nutrient components (such as crude protein) by employing the following equation ... 

This chapter concentrates on the possibility of producing SCP from petrochemical feed stocks, such as n-paraffin, methane, or methanol. Between 1960 and 1980, the idea to produce SCP from crude oil sources found a lot of attention and several large-scale plants with capacities of several 100,00 tons/year were built, for instance in southern Italy. Hopes were high at the time, but the development made only slow progress. One of the reasons could be the choice of the location, which is far away from both, the source of the feedstock and the consumers of the product. Another is that oil and natural gas are expensive feed stocks, because they also have other uses. Anyway, the technology for protein production from chemicals exists and may be applied with more success in other areas of the world, where more favorable starting conditions exist. 

The first soybean protein ingredients made commercially available for food use included full-fat and defatted soy flours and grits (3, 7, 8). These products contain ca. 46-59% protein (NX 6.25) on a moisture-free basis and are available with various heat treatments for specific end-use. Soy protein concentrates and soy protein isolates were introduced into the market about 15 years ago (3, 9, 10, II). By definition soy protein concentrates must contain no less than 70% protein (N X 6.25) and isolates no less than 90% protein (N X 6.25), all on a moisure-free basis. In the past several years there has been much activity in the commercialization of textured soy protein products intended for the extension and replacement of meat. These textured products may be obtained through fiber spinning, shred formation, extrusion, or compaction (12, 13, 14, 15). In addition, soybean milk solids and the heterogeneous proteins in soybean whey might serve as useful substrates in chemical modifications for food use. This short recitation of commercial products illustrates the type of crude protein fractions available for practical modification. Many useful functional properties have been ascribed to these new food proteins. 

The used BSG hydrolyzate conqjosition is shown in Table 2. It has approximately 26 g F of monosaccharides and a low level of microbial inhibitors, specially aliphatic acids, and furan derivatives compared to similar hemicellulosic hydrolyzates used for SCP production, e.g., eucalyptus wood [28] and sugar cane bagasse [7,8]. Also, it has a low content of phenolic compounds. Crude protein has a concentration of about 1.2 g F. Much of this nitrogen (about half) is in ammonia form, the rest as amino acids (data not shown). 

The net protein requirement for milk production is the protein content of the milk. Up to day 22 of lactation, the crude protein content of milk (g/kg) can be estimated as 10 X (3.43 - 0.066 d), where d = days in milk. After day 22, milk protein concentration is assumed to be 19.6 g crude protein/kg. Using an efficiency of utilisation of 50 per cent and a digestibility of 79 per cent results in a dietary crude protein requirement for milk production of approximately 50 g/kg milk. Previous protein requirements were based on digestible crude protein, but more recently NRC (2007) argues that the lack of information regarding digestible crude protein content of feed-stuffs commonly fed to horses does not justify its use, and that requirements should be based on dietary crude protein. The crude protein requirement (g/day) for maintenance is therefore calculated as 1.44 W and total requirements for milk production as CP requirement = 1.44W + 50Y. For a 500 kg mare producing 15 kg of milk, the daily crude protein requirement (g/day) is estimated as 720 + 750 = 1470. 

Preparation of protein ingredients from seed meal is also possible since it contains about 26% of crude protein. In addition to the traditional uses of seed meal, recovery of its protein fraction, in the form of isolate or concentrate, may provide value-added products for use in food and feed formulations. The flaxseed polysaccharide (mucilage) fraction, which is located on the outer seed coat, once isolated has potential use as a food gum or dietary fiber (Mazza and Oomah, 1995). 

Soy protein concentrates typically contain 70% to 72% crude protein. For example, bacon strips can be made by a texturization processes involving twin screw extrusion (19). The high-protein content yields the protein as the continuous phase. Note that soy beans, like most seeds, also contain some triglyceride oils, important in cooking the final product. 

C diphtheria vaccine is typical of a crude protein toxoid vaccine. Here the 58 kDa toxin is the antigen, and it is converted to a toxoid with formaldehyde and crudely purified. The cells are first separated from the toxin by centrifugation. Sometimes the pathogen culture is inactivated with formaldehyde before centrifugation. The supernate is treated with formaldehyde to 0.75%, and it is stored for 4 to 6 weeks at 37°C to allow complete detoxification (Pappenheimer, 1984]. The toxoid is then concentrated by ultrafiltration and fractionated from contaminants by ammonium sulfate precipitation. During detoxification of crude material, reactions with formaldehyde lead to a variety of products. The toxin is internally cross-linked and also cross-Hnked to other toxins, beef peptones from the medium, and other medium proteins. Because detoxification creates a population of molecules containing antigen, the purity of this product is only about 60 to 70%. 

Beet extract is also used as a colorant. Extract is sold as either a concentrate prepared by evaporating beet juice under vacuum to a total solids content of 40-60%, or as a powder made by spray-drying the concentrate. Both products usually contain ascorbic or citric acid as a stabilizer, and a preservative such as sodium propionate. On a dry-weight basis, beet extract typically contains between 0.4 and 1.0% betanin, 80% sugar, 8% ash, and 10% crude protein. 

Colmenero, J. J. and G. A. Broderick, 2006. Effect of dietary crude protein concentration on milk production and nitrogen utilization in lactating dairy cows. J. Dairy Sci. 89, 1704-1712. 

Initially fermentation broth has to be characterised on the viscosity of the fluid. If the presence of the biomass or cells causes trouble, they have to be removed. Tire product is stored inside the cells, the cells must be ruptured and the product must be freed. Intracellular protein can easily be precipitated, settled or filtered. In fact the product in diluted broth may not be economical enough for efficient recovery. Enrichment of the product from the bioreactor effluents for increasing product concentration may reduce the cost of product recovery. There are several economical methods for pure product recovery, such as crystallisation of the product from the concentrated broth or liquid phase. Even small amounts of cellular proteins can be lyophilised or dried from crude solution of biological products such as hormone or enzymes.2,3... 

Figure 11.9 Production of rhGH in . coli (as an intracellular protein). Subsequent to fermentation, the cells are collected by centrifugation or filtration. After homogenization, nucleic acids and some membrane constituents are precipitated by the addition of polyethyleneimine. Ammonium sulfate precipitation of the supernatant concentrates the crude rhGH preparation. Chromatographic purification follows, as illustrated...

The objectives of the present study were to compare the processes of protein and starch concentration by dry air classification and wet alkali extraction of protein and starch from field pea and fababean. The yields, composition and functionality of the crude and refined products were compared. 

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