Milk protein fibres

In contrast, the whey proteins are relatively small globular proteins. a-Lactalbumin represents about 20 % of the protein content of bovine whey (3.5 % of total bovine milk protein), and it is the principal protein in human milk (Brew and Grobler, 1992). Nanotube assembly has been discovered in some solutions containing a hydrolysed derivative of this protein. And it appears that the a-lactalbumin nanotube is unique in the sense that it is the only artificial nanotube that has so far been made from a food protein (Graveland-Bikker et al., 2004 Graveland-Bikker and de Kruif, 2006). As for p-lactoglobulin, it has the capacity under certain specific conditions to form nano-fibres in aqueous media (as can various other globular food proteins, such as ovalbumin, soy proteins, and bovine serum albumin) (van der Linden, 2006 Nicolai, 2007). 

Synthetic fibres made from proteins are Aralac from milk protein casein, Vicara from corn protein zein, and Saralon from peanut protein. These fibres look like wool and can also be dyed just like wool or silk is dyed. These fibres are blended with wool to add strength. 

The raw materials used for the preperation of regenerated protein fibres may be milk, soyabeans, peanuts and zein. Sometimes alkaline solutions of gelatin, albumin and other raw materials like waste wool, silk and feathers may be used. Fibrolane (Great Bretain) and Merineva (Italy) are made by dissolving casein in sodium hydroxide, and then by extrusion into an acid/saltbath. The fibres formed in this way... 

This subject is discussed in Chapter 15, but a brief summary is given here, as an introduction to fat metabolism. The three major components of a human diet are meat, fish and plants, and the fats associated with each component can be different. Meat usually comprises the muscle of mammals and birds but it is always associated with fat. Even apparently lean meat may have a high fat content a 250 g beef steak may contain 60 g fat in addition to its 80 g protein. Some of this will be adipose tissue between muscles the remainder is triacylglycerol (TAG) within the fibre. In addition, milk and other dairy products contain significant amounts of fat about a quarter of the fat in the average UK diet comes from dairy produce. 

The success of the regenerated cellulosic fibres stimulated the imagination of chemists. The obvious sequel was to produce a regenerated protein with properties resembling wool or silk. Much research and capital expenditure has been devoted to the production of lanital from milk casein, ardil from ground-nut protein, saran from soya bean, and vicara from maize. None of them proved really commercially successful and their manufacture has now virtually ceased. 

Cellulose-based plastics, particularly cellulose nitrate and acetates, were the most commercially important semi-synthetics up to the 1940s and were used as the base for photographic film, textile fibres, moulded goods and in lacquers. Naturally occurring polymer cellulose in the form of cotton linters or wood pulp is chemically treated to increase its solubility. Cellulose has a high molecular weight of between 100000 and 500000 and an empirical formula C0H1OO5. Casein-formaldehyde is the only protein-based moulded plastic that achieved commercial success. It is based on cow s milk and is still produced in very small quantities for specialist items such as hand-coloured buttons. 

Azlons are fibres regenerated from protein sources that include soy, com, peanuts and even milk. Products used in sports fabrics derived from com will be discussed under synthetics. 

Other than animals, agricultural materials can also be cmisidered as an ideal source of protein and are prospective materials for the preparation of fibres. Fibres of regenerated protein were produced commercially in between 1930 and 1950, and by today s standards, they would be considered natural, sustainable, renewable, and biodegradable. Casein from milk was used by M/s Courtaulds Ltd. to make Fibrolane and by M/s Snia to make Lanital groundnut (peanut) protein was used by... 

Method for stabilising fibres formed from milk or soya bean protein using an acylating agent such as acetic anhydride and ketenes which may be in gaseous form... 

Others explored techniques to improve the elasticity and flexibility of the fibre after washing (US 2,309,113 see Table 13.2). Acetylation, sometimes using acetic anhydride at temperatures of 80°C or above, could be used to improve colour, handle and dyeing performance." Atlantic Research Associates used this approach to stabilising fibres formed from either milk or soya bean protein. The acylating agent, which could be in gaseous form, was used to make the newly formed fibres more resistant to water, acids and alkalis (GB... 

Based on a meta-analysis of 32 studies Broderick et al. (2010) concluded that the omasal canal non ammonia-N flows were equal to N intake at ruminal ammonia concentration of 5.1 mmol/l and milk urea concentration of 17.8 mg/100 ml. Under such circumstances there is no net absorption of ammonia from the rumen but the amount of protein degraded in the rumen equals the microbial N synthesis. Based on the above mentioned criteria ruminal ammonia concentrations were critically low on all urea infusion levels in the current study. In spite of low ruminal ammonia-N concentrations the major proportion (0.67) of urea-N infused into the rumen was excreted in urine suggesting that the rumen microbes couldn t completely utilize extracellular ammonia-N under limiting conditions. The current flndings indicate that the microbial N synthesis was more sensitive to moderately low ruminal ammonia N concentrations than fibre digestion because intraruminal urea infusions seemed to increase microbial N synthesis but no effect was observed in fibre digestion or feed intake. 

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