The effects of mannanase activity on viscosity in different gums

Abstract

Beta (β)-mannanases, hydrolyzed 1,4-β-D mannosidic bonds in mannan, galactomannan, glucomannan, and galactoglucomannans, can be used to reduce the viscosity of foods for gum modification. Locust bean gum (LBG) and guar gum (GG) have a wide range of use from food to textile as a thickening agent. In this study, the effect of β-mannanase on the viscosity of the LBG and GG was investigated. The rheological analysis showed that the flow behavior of LBG and GG changed from pseudoplastic to Newtonian after hydrolysis. The highest viscosities of non-hydrolyzed LBG (%1) and GG (%1) were 1,864.30 and 1,883.80 mPa/s, and the lowest values were 1.60 mPa/s for hydrolyzed LBG (0.5 g/L) and 2.90 mPa/s for GG (0.5 g/L), respectively. A significant decrease in viscosity was observed on the gums with the use of β-mannanase. Results showed that the β-mannanase enzyme can be used for gum modification. Practical applications Beta (β)-mannanase enzymes could hydrolyze gums, which include mannan units, such as galactomannans and glucomannans. Galactomannans as locust bean gum and guar gum have large scale applications in different food, cosmetic, and pharmaceutical products. They could have been used as a thickener, stabilizer, emulsifier, and gelling agent in emulsion and suspension systems. Additionally, they are also used as food ingredients in bakery goods (icings and cake mixes) and dietary products, coffee whiteners, baby milk formulations, and prebiotic sources. Despite the valuable properties of gums, their solutions have higher viscosity. Consequently, water-soluble application in industry and cleaning of gum processing equipment usually harder. Using β-mannanase could have overcome the negative effect of viscosity. Moreover, partially hydrolyzed LBG and GG solutions using β-mannanase could be benefited as a prebiotic source in daily nutrition.