Optimization of amount of amylose, methylcellulose and hydroxypropylmethylcellulose for maximum tensile strength and minimum water vapour permeability of corn starch based self-supporting films

Abstract

Corn starch based self-supporting film has been developed from a fixed quantity of polymer that contains corn starch and functional polysaccharide such as amylose, methylcellulose and hydroxypropylmethylcellulose. The optimum amount of functional polysaccharide in order to obtain maximum tensile strength and mimimum water vapour permeability of film has been determined. It is observed that increasing addition of functional polysaccharide (amylose/methylcellulose/ hydroxypropylmethylcellulose) in blend increases the tensile strength of film to a maximum value, following a decreasing tendency with further addition. The trend for water vapour permeability is found to be opposite. The concentration of functional polysaccharide at the inflection point of maximum tensile strength and minimum water vapour permeability does not always match, thus necessitating the need of optimization. <span style="mso-bidi-font-weight:bold">Response surface methodology using design expert numerical optimization could successfully predict the optimum value of functional polysaccharide in starch blend to attain maximum tensile strength and minimum water vapour permeability of developed film. For amylose, methylcellulose, and hydroxypropylmethylcellulose, the optimized levels are found as 0.65, 0.10, and 0.22% in case of glycerol–water plasticizer, and 0.74, 0.08, 0.29% in case of glycerol-polyethylene glycol-water plasticizer respectively.

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