Bioenzyme mediated hydrodistillation (BMHD) for extraction of mint oil from mentha leaves: improvement in yield and menthol content

Bioprocess Biosyst Eng. 2024 Jun 14. doi: 10.1007/s00449-024-03041-0. Online ahead of print.


The present study optimized pre-treatment conditions for bioenzyme-mediated hydro-distillation (BMHD) for extraction of mint oil from mentha leaves and the results were compared with those of traditional hydro-distillation (HD) method using response surface methodology. The bio-enzymes produced from moringa leaves had maximum pectinase activity (287.04 µg of sugar/min/ml) followed by xylanase (87.78 µg of sugar/min/ml) while endoglucanase, exoglucanase and amylase activities were comparatively low. The optimized conditions for HD were 69.08 temperature for 173.70 min with water:sample of 10.0. The optimized conditions for enzyme pre-treatment of mentha leaves by BMHD were enzyme concentration of 8%, for a period of 120 min at an incubation period of 40 ℃. The yield (%) and menthol content (%) of the oil at optimized conditions by HD were 1.55 ml/100 g of sample and 56.40% menthol content, respectively, and for BMHD the yield and menthol content (%) of the oil at optimized conditions were 3.69% and 72.80%, respectively. It was found that BMHD leads to a 130% increase in the yield of mint oil and a 10% increase in menthol content as compared to the HD method. No significant difference in physical parameters was observed in mint oil extracted via both methods. Therefore, BMHD is a cost-effective and sustainable approach having an edge over the HD method without compromising the quality and could be a viable approach for commercial purposes.

Keywords: Bioenzyme mediated hydro-distillation (BMHD); Hydro-distillation (HD); Mentha leaves; Menthol content; Mint oil.