Effects of Citronella Essential Oil and Citronellal on the Storage and Preservation of Potatoes

To evaluate the sprout-suppressing and storage-preserving effects of citronella essential oil and its major component citronellal on potatoes, the chemical composition of citronella essential oil were profiled using gas chromatography-mass spectrometry (GC-MS). We fumigated ‘Inner Mongolia V7’ potatoes with citronella essential oil or citronellal at a consistent concentration (25 mg/L) every seven days and stored at 20±2 ℃ and 90% relative humidity. During storage, we monitored sprouting rate, weight loss, respiratory intensity, malondialdehyde (MDA) content, the production rate of superoxide anion, hydrogen peroxide content, and the activities of the antioxidant enzymes, included superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX). GC-MS analysis showed that citronellal accounted for 31.86% of the total components in citronella essential oil, making it the most abundant constituent. At day 70 of storage, the sprouting rate in the citronellal group was 25%, significantly lower than the control (100%) and the citronella essential oil group (36.67%) (P <0.05). The weight loss decreased by 25.23% in the citronella essential oil group and 24.31% in the citronellal group, respectively, compared with the control group. The respiratory intensity reached 0.21 mg/(kg·h) in the citronella essential oil group and 0.14 mg/(kg·h) in the citronellal group, both markedly lower than the control (0.53 mg/(kg·h)) (P <0.05). In the antioxidant system, at day 28 of storage, the production rate of superoxide anion decreased by 63.78% in the citronella essential oil group and 68.91% in the citronellal group, compared with the control group, respectively. At day 70 of storage, hydrogen peroxide content was 31.63% lower (citronella essential oil) and 33.74% lower (citronellal) relative to the control. At the end of storage, the activities of SOD, CAT, POD, and APX in the citronella essential oil-treated potatoes increased by 23.39%, 24.49%, 62.83%, 98.96%, respectively, compared with the control. In the citronellal-treated potatoes, the activities of these enzymes increased by 29.26%, 24.49%, 113.90%, 161.53%, respectively. The content of MDA decreased by 12.12% (in the citronella essential oil group) and 17.36% (in the citronellal group), respectively, compared with the control. Overall, citronella essential oil and citronellal delayed sprouting, reduced respiratory intensity and weight loss, suppressed ROS accumulation, and enhanced antioxidant enzyme activities, thereby mitigating membrane lipid peroxidation and oxidative damage. Citronellal showed a stronger preservative effect than citronella essential oil, highlighting its potential as a natural sprout inhibitor for postharvest potato storage.