Steam-distilled Basil Essential Oil for Strawberry Preservation and Its Effects on Fruit Quality

Abstract

Aims: To compare the yields of basil essential oils (BEOs) extracted from Thai basil (Ocimum basilicum var. thyrsiflorum) and sweet basil (Ocimum basilicum L.) by steam distillation, with or without cellulase-pectinase pretreatment, and to evaluate the recovered oils as natural fumigants for extending the postharvest shelf life of strawberries. Study Design: This laboratory-based experimental study aimed to evaluate the preservative effect of basil essential oils (BEOs) derived from two basil varieties using two extraction methods. The BEOs were applied as fumigants to strawberries stored at 25 °C for 72 h. The results were compared with those of a blank control group. Place and Duration of Study: Department of Science Education, School of Education, Zhejiang International Studies University, Hangzhou, China, from March to June 2024. Methodology: Oven-dried basil leaves (50 °C, 24 h) from both varieties were soaked in water and subjected to steam distillation for 240 min, with or without pretreatment with 1.5% (w/v) cellulase-pectinase in citrate buffer. Oil yields (w/w) were determined in triplicate. Strawberries of uniform maturity were selected and fumigated with Thai basil essential oil or sweet basil essential oil at 25 °C for 72 h. Preservation performance was evaluated by measuring weight loss rate, soluble solids content (SSC), and titratable acidity. Conclusion: Overall, basil leaves subjected to enzyme pretreatment exhibited lower essential oil extraction efficiency than those without enzyme treatment. Fumigation with both Thai basil essential oil and sweet basil essential oil slowed strawberry weight loss. Additionally, Thai basil oil best preserved soluble solids content (SSC) (6.00%), whereas sweet basil oil marginally outperformed Thai basil oil in maintaining titratable acidity (TA) (1.59%). These findings suggest that BEO fumigation suppresses respiration and the loss of moisture, sugars, and organic acids. Therefore, steam-distilled BEOs—whether extracted directly or with enzyme assistance—represent promising natural preservatives for extending strawberry shelf life.