Effect of Different Postharvest Methods on Essential Oil Content and Composition of Three Mentha Genotypes

Abstract

Mentha sp. is commonly used for essential oil (EO) extraction and incorporated in multiple products of food and pharmaceutical industries. Postharvest management is a key factor in line of production to preserve quality-determining plant ingredients. This study focused on the effects of two different postharvest processes on EO content and the composition of three different Mentha genotypes (Mentha × piperita ‘Multimentha’, Mentha × piperita ‘Fränkische Blaue’ and Mentha rotundifolia ‘Apfelminze’). They were cultivated under greenhouse conditions. One postharvest treatment consisted of drying Mentha as whole plant after harvesting and later separating leaves from stems. In the second treatment, leaves were separated from stems directly after harvesting and then dried. EO content was determined by steam distillation and composition of EO was characterized by GC/MS analysis. Key findings of the study are that the postharvest processing treatments had no significant influence on the content or composition of the EO. Only the genotype ‘Fränkische Blaue’ showed a significantly higher EO content in the dry separated treatment at the third harvest (2.9 ± 0.15 mL/100 g DM (sD)) than separated fresh (2.4 ± 0.24 mL/100 g DM (sF)). However, genotype selection and harvest time had a clear impact on EO content and composition.