Improving yield and quality characteristics of kaffir lime oil (citrus hystrix DC) by solid fermentation pretreatment using tempeh yeast

The industrial development of flavor and fragrance currently leads to natural ingredients. Kaffir lime is a potential ingredient developed from Indonesia, but distillation of essential oil in Indonesia generally results in low yields and quality. Fermentation as the initial treatment of distillation would improve the yield and quality of essential oil. The fermentation process is usually performed as pretreatment using cellulolytic bacteria such as Trichoderma harzianum, Trichoderma viride, or Trichoderma reesei, but the use of those bacteria is considered less practical for essential oil distillation process. Therefore, this research utilized tempeh yeast to increase yield and quality of essential oil. Since tempeh yeast consists of Rhizopus producing hyphae, it is expected that hyphae are able to penetrate the tissue, making it easier for oil to get out of the leaves. The aerobic fermentation process was carried out by continuous addition of air inside the fermenter with air compressor. Fermentation was observed within four days. The distillation was performed by using steam distillation method. The result of this study showed that leaf lime essential oil with fermentation process of day 3 produced the highest yield of 0.67%, which increased 20% compared to non fermented leaves. The composition of leaf lime essential oil was 87.92% Citronellal, 1% beta-caryophyllene, 0.3% Citronellal acetate, 0.9% Citronellol, and 1.77% linalool, which comply to local industry standard.