Preparation of CMC from Pineapple (Ananas comosus-Smooth Cayenne Cultivar) Peel and Its application as Edible Bio-plastics

Abstract

Pineapple (Ananas comosus–Smooth cayenne cultivar) peel is agricultural waste that rich in cellulose. There is many way to utilize this waste to become more valuable product such as cellulose or its derivative. The objectives of this research are to prepare CMC from pineapple peel (CMCpp) and use the obtained CMC as edible film material. The CMCpp obtained from reacting the extracted cellulose from dried pineapple peel with monochloroacetic acid. The CMCpp has been successfully synthesized with degree of substitution (DS) of 1.040±0.104 for bleached CMC and of 0.601±0.087 for unbleached CMCpp, and the water solubility of bleached CMCpp and unbleached CMC were 76.92% and 33.93%, respectively. The CMCpp had lower solubility than commercial CMC (CMCc) which can be dissolved in water 100% (DS of CMC =1.0). The color measurement showed that the bleached CMC (L*=87.37; a*=-0.71; b*=8.19) was nearly met with the color of CMC (L*=89.57; a*=-0.91; b*=6.86) but brighter than unbleached CMCpp (L*=70.03; a*=4.07; b*=18.90). The effects of plasticizer (glycerol and sorbitol with concentration 10%; 20%; and 30% [w/w of CMC]) on the films properties were also investigated. The results showed that increasing the concentration of plasticizer decreased the tensile strength but increased %elongation of CMC films. The films with glycerol as plasticizer showed lower tensile strength than films with sorbitol as plasticizer. Adding glycerol and sorbitol did not give significant effect to the water solubility index but increased water vapor transmission rate (WVTR) of films. FT-IR spectra showed that the functional groups of each film with and without plasticizer are not significantly different. The results indicated that the film of CMC from pineapple peel can be used as edible film for the other applications.