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.