Effect of Ethanol Addition on Subcritical Water Extraction of Pectic Polysaccharides from Passion Fruit Peel

Abstract

The effect of ethanol addition (0 − 30% v/v) on subcritical water extraction (SCWE) of pectic polysaccharides from passion fruit peel was investigated. The peel was extracted in a batch-type reactor at the treatment temperatures range of 100 − 160C. As a result, low molecular weight pectic polysaccharides in a range of 15.4 − 38.5 kDa were obtained. Higher treatment temperatures tended to give higher yields while the addition of ethanol gave adverse effect, except for adding small amount at high temperatures. The maximum yield (12.28% dry matter basis) was obtained from the treatment at 140C using 10% ethanol. The major composition of extracted pectic polysaccharides was galacturonic acid (72.11 − 94.76%). Additionally, this study demonstrated that the addition of ethanol resulted in pectic polysaccharides that possessed higher 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and total phenolic content (TPC). Practical Applications Subcritical water extraction (SCWE) is an environmentally friendly method that can be used for extraction of pectic polysaccharides from passion fruit peel, which is a major waste from juice production. Addition of ethanol was successful to enhance the extractability of some bioactive compounds in the peel and resulted in pectic polysaccharides with higher total phenolic content (TPC) and free radical scavenging activity, which might be useful as functional food ingredients.