Ma-khwaen essential oil vapour suppresses potato sprouting under tropical ambient storage via GA3-ABA modulation, oxidative stress and carbohydrate metabolism.

BACKGROUND

Sprouting is a major postharvest challenge in potato storage, accelerating physiological ageing, starch mobilisation and α-solanine accumulation, thereby reducing processing quality and food safety. With the phase-out of hazardous synthetic sprout inhibitors, safe and residue-free alternatives are needed. This study evaluated the vapour-phase efficacy of three essential oils (EOs; lime peel, holy basil and ma-khwaen) applied at a nominal loading of approximately 70 μL L-1 (v/v) as overnight fumigation to 'Spunta' potato tubers stored under ambient conditions (28 ± 4 °C, 65-83% relative humidity).

RESULTS

Ma-khwaen EO (MKEO) was the most effective in reducing postharvest deterioration. After 63 days of storage, MKEO-treated tubers maintained weight loss below 1.0% compared to more than 2.2% in non-treated controls. Sprouting incidence was reduced to less than 50% with sprout lengths ≤ 5 mm compared to more than 90% incidence and sprout length > 10 mm in controls. MKEO delayed the attainment of 50% sprouting beyond 63 days compared to the first week of storage in controls. MKEO reduced α-amylase activity by 25-40% compared to water-treated and non-treated controls, resulting in lower accumulation of reducing sugars during storage. On day 63, MKEO further reduced H2O2 accumulation, antioxidant enzyme (peroxidase and catalase) activities, lowered GA3 levels and decreased α-solanine content by 32% compared to controls at the same time as elevating abscisic acid levels.

CONCLUSION

MKEO effectively suppressed sprouting and delayed potato tuber deterioration by regulating hormonal balance, oxidative status and carbohydrate metabolism. MKEO represents a promising eco-friendly and residue-free sprout suppressant for ambient potato storage in tropical regions. © 2026 Society of Chemical Industry.