M. B. Bera

Welan gum: microbial production, characterization, and applications.

Microbial exopolysaccharides are of high molecular weight, environment friendly valuable natural polymers, having applications in diverse areas such as food industry, pharmaceutical industry, cement systems and cosmetics industries. Welan gum, a microbial product holds an important place among the exopolysaccharides due to its novel properties and potential applications. The biopolymer welan gum is synthesized by the fermentation process mainly by the Alcaligenes sp., and is composed of polymer of tetrasaccharide backbone chain containing l-mannose, l-rhamnose, d-glucose, and d-glucuronic acid. It acts as a thickening, suspending, binding, emulsifying, stabilizing and viscosifying agent. It has important commercial applications in the cement systems. This review is primarily focused on the microbial production, purification, recovery, and the characterization based on the available published literature on the welan gum. Besides this, the biosynthesis and the various process factors affecting the production as well as properties of welan gum and its various applications have also been addressed.

Fructo-oligosaccharides: Production, Purification and Potential Applications

The nutritional and therapeutic benefits of prebiotics have attracted the keen interest of consumers and food processing industry for their use as food ingredients. Fructo-oligosaccharides (FOS), new alternative sweeteners, constitute 1-kestose, nystose, and 1-beta-fructofuranosyl nystose produced from sucrose by the action of fructosyltransferase from plants, bacteria, yeast, and fungi. FOS has low caloric values, non-cariogenic properties, and help gut absorption of ions, decrease levels of lipids and cholesterol and bifidus-stimulating functionality. The purified linear fructose oligomers are added to various food products like cookies, yoghurt, infant milk products, desserts, and beverages due to their potential health benefits. This review is focused on the various aspects of biotechnological production, purification and potential applications of fructo-oligosaccharides.

Optimization of Osmotic Dehydration Process of Carrot Cubes in Sodium Chloride Solution

For optimization of osmotic dehydration process of carrot cubes in sodium chloride solution by response surface methodology, the experiments were conducted according to Face-Centered Central Composite Design (CCF). The independent process variables for osmotic dehydration process were osmotic solution concentrations (5 -15% w/v sodium chloride), temperature (30 -50°C) and process durations (90 -150 minutes). The osmotic dehydration process was optimized for maximum water loss, minimum solute gain, maximum retention of colour and sensory score. The optimum conditions were 7.9 % sodium chloride concentration; 30°C osmotic solution temperature and 150 minutes process duration.