Polysaccharides industrial uses

In homogeneous liquid systems, sonochemical effects generally occur either inside the collapsing bubble, — where extreme conditions are produced — at the interface between the cavity and the bulk liquid —where the conditions are far less extreme — or in the bulk liquid immediately surrounding the bubble — where mechanical effects prevail. The inverse relationship proven between ultrasonically induced acceleration rate and the temperature in hydrolysis reactions under specific conditions has been ascribed to an increase in frequency of collisions between molecules caused by the rise in cavitation pressure gradient and temperature [92-94], and to a decrease in solvent vapour pressure with a fall in temperature in the system. This relationship entails a multivariate optimization of the target system, with special emphasis on the solvent when a mixed one is used [95-97]. Such a commonplace hydrolysis reaction as that of polysaccharides for the subsequent determination of their sugar composition, whether both catalysed or uncatalysed, has never been implemented under US assistance despite its wide industrial use [98]. 

Sodium hyaluronate, or HA, is a biocompatible polysaccharide that is encountered in medicine and the cosmetics industry. Its macroscopic properties are highly sensitive to its hydration level, which is the reason why it has been the object of many studies. When in its dried state, or scarcely hydrated, it is stiff. In this state it may act as a skin-stiffening agent, smoothing wrinkles for instance. When highly hydrated, it acts as a lubricant that is found in synovial fluid. The elucidation of its hydration mechanism has shown us the role of the developing H-bond network in the change of its properties and, at the same time, the power and sensitivity of IR spectrometry to observe water molecules in macromolecules. 

HA is the most expensive bacterial polysaccharide, a medical grade HA sells at US 40,000-60,000 per kg. The HA industry is worth an estimated US 1000million per year. The first hyaluronan biomedical product, Hyalon, was developed in 1970s. The polymer from Streptococcus epizooticus or related species is identical to HA from the human and animal body. 

Today, xanthan enjoys worldwide approval and has become one of the most widely investigated polysaccharides [24]. Xanthan gum enjoys wide application in industrial fields, including food, oil recovery, cosmetics and pharmaceuticals [4]. Its utilization for food uses has been approved by the US Food and Drug Administration (FDA) in 1969 [24]. It is utilized as stabilizer in emulsions and suspensions [4] like toothpaste and ointments, sustained release agent [86,87] and compression enhancer [1]. 

There has been a worldwide realization diat nature-derived monosaccharides, disaccharides, oligosaccharides and polysaccharides can provide us with the raw materials needed for the production of numerous industrial consumer goods (Kunz, 1993 Varma, 2003 Pacitti, 2003). This section will deal with the role of sugar molecules anchored like pendants onto a synthetic polymer, reminiscent of the crown ether type molecules pendant on polystyrene and other synthetic chains which created a whole new area of research with far-reaching outcomes (Gokel and Durst, 1976 Varma, 1979 Varma et al, 1979 Smid et al, 1979a, Shah and Smid, 1978 Smid et al, 1979b Varma and Smid, 1977). 

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