Obtaining and characterization of modified mannan from the coffee sludge

Abstract

Mannans are polysaccharides of natural origin. Their main chain consists of residues of D-mannose. They have an immunomodulatory effect, able to induce macrophage activation, inhibit tumor growth and virus development, normalize blood cholesterol, etc. Manooligosaccharides are effective prebiotics The main way to obtain mannan is to extract their alkaline solutions. This makes it impossible to use this polysaccharide in food technologe. This study proposes a biotechnological method of producing water-soluble mannan from coffee sludge. As a source of mannan used a by-product of obtaining instant coffee at the Odessa Combine Food Concentrates which is formed in the processing of coffee beans Arabica. The chemical composition of this coffee sludge was investigated. It is dominated by water-insoluble carbohydrates which are represented by hemicellulose polysaccharides and cellulose. Analysis of the monosaccharide composition of hemicelluloses showed that the hydrolyzate contains mannose, glucose and galactose residues in a ratio of 6: 0,5: 3., which may indicate the presence of galactomannan in their composition. The developed method involves the treatment of the coffee sludge with enzyme preparation with beta-mannanase activity. The process was carried out in aqueous medium at temperature 50 °C, varying the hydromodule in the range of 30… 50, the ratio of enzyme: substrate (1:25, 1:50 and 1:100) for 24…72 hours. This study presents the characteristics of the monomer composition and molecular weight distribution of polysaccharide samples obtained in this way. Only mannose was found in the hydrolyzate of water-soluble mannan. The rational conditions of enzymatic processing of raw materials are determined. The modified mannan is soluble in water. It contains the highest number of target fragments with a molecular weight of about 20 kDa which are considered to be the most physiologically active. Subsequently the modified mannan can be used in nanotechnology functional food ingredients and dietary supplements.