Ethanol Washing, Pectinase Pretreatment and Oleoresin Saponification of Tomato Waste to Increase Lycopene Purity

In this study the best method of extracting lycopene from tomato skin, waste and the effect of pectinase enzyme pre-treatment at 2, 4, 6, 8, and 10 ml/Kg concentrations and 30, 60, 90 minutes of effective times for tomato waste and also washing with 94% ethanol at 60 °C for 5 seconds were studied in order to determine the best method of increasing lycopene purity in oleoresin. Lycopene extraction was performed at 30 °C for 16 hours with hexane: ethanol: acetone (1:1:2) at ratios of 1:10 to dried samples with gentle stirring. In order to prevent the lycopene oxidation 0.05 percent w/w of BHT was used. The effect of oleoresin saponification to increase the purity of lycopene in oleoresin was also studied by propylene glycol and potassium hydroxide 45% (w/w) and deionized water at the concentration of 30%, 10% and 10% oleoresin by weight, respectively. The effect of enzyme pretreatment and ethanol and also oleoresin saponification had a significant effect on oleoresin and lycopene extraction and extraction efficiency from tomato waste (P<0.01). Ethanol treatment significantly increased lycopene purity in oleoresin (P<0.01). In waste samples treating with 10 ml/kg enzyme concentration at 90 minutes of effective time resulted in highest extraction of lycopene (279.5 mg/100g oleoresin). It has been shown that if saponification is not employed in lycopene extraction from tomato waste the ethanol washing pre-treatments should not be applied.