Potential Use of Rambutan (Nephelium lappaceum) Seed Starch as a Component of Bioplastic Product

Abstract

INTRODUCTION

The problem with plastic waste is not only about it's taking up large amounts of space, but also include chemical contaminations, environmental issues, and the like due to its slow decay rate. In reducing the problem of plastic waste, bioplastics that came from renewable sources were developed (Woodford. 2014). As an alternative, the use of bioplastics is being promoted in obtaining natural polymers from agricultural products, cellulose, or potato and corn starch waste. This study explored the possibility to extract starch from rambutan seeds and determine its potential use as a component for bioplastic product.

METHOD

In extracting starch from rambutan seeds, the following procedures were followed: Immersion of seeds in 2%NaSO4 for 72 hours, milling, sieving, decantation and washing, centrifugation (3,000 rpm for 3 minutes, washing in 95% ethanol and centrifugation for 3 times and air drying of the extract for one week at room temperature. Starch extracted was a total of 125.1 grams from 623.4 grams of rambutan seeds giving a total mean yield of 20%. Further, the starch was characterized by its density, and iodine test, ethanol emulsion test. The extracted starch was used to produce a bioplastic. The product was tested by its tensile strength, density and water uptake, and biodegradability.

RESULTS

Starch extracted was a total of 125.1 grams from 623.4 grams of rambutan seeds giving a total mean yield of 20%. The computed density of the rambutan seeds starch is 0.76 g/cm3 from its mass of 76 g and volume of 100 cm3. The FTIR spectra show a stretch of a hydroxyl group (O-H) from 3,200 cm-1 to 3,650 cm-1 and a peak of C-O bond ranging from 1,050 cm-1 to 1250 cm-1, attesting the purity of the extracted rambutan seed starch. The computed tensile strength of the bioplastic film product of the study is 1,296.875 Pa. Its density is 1.29 g/cm3 when dry and after soaking in water for 6 hours, density was computed to be 1.4 g/cm3, its computed water uptake is 10%. A soil test shows that for a maximum average of 12 days, the bioplastic film completely degrades in any kind of soil.

DISCUSSIONS

Rambutan seeds starch extraction is feasible and has high potential as a material or component for the production of bioplastic materials. The FTIR result shows the purity of the rambutan seed starch sample, and the biodegradability test exhibits positive result since the bioplastic film can degrade in a span of two weeks in any kind of soil.