The Temporal Relationship between Volatile Biosynthesis and Other Ripening Parameters in Banana Fruit

Abstract

Banana [Musa sp.9AAA group0, Cavendish] fruit are climacteric in nature, undergoing a rapid rise in ethylene production and respiration. Ethylene production can peak within 8 h of a detectable rise in production and respiration peaks within 24 h. These rapid changes permit precise timing for events related to or dependent on ethylene presence. Using rapid analytical methodology, we investigated the dynamic changes in volatile biosynthesis and its relation to other ripening parameters. Ungassed, mature-green banana fruit were placed individually at 23°C in flow through glass chambers. Ethylene production, respiration, chlorophyll fluorescence, skin color (hue angle) and volatile production were monitored. The climacteric rise and subsequent fall in ethylene production was found to be complete within 20 h. The respiratory rise peaked 20 h after the initial rise in ethylene production. The onset of the decline in chlorophyll fluorescence, skin color (hue angle) were coincident with the rise of ethylene and respiration, which indicated that the chlorophyll fluorescence may be used to monitor the banana fruit ripening. Volatile production was found to begin ≈60 h after the onset of the ethylene climacteric, peaking 3 to 4 days later. The ester precursors butyric acid and 3-methylbutanol were used in feeding experiments at different developmental stages for pulp and peel. Full ester-forming capacity was found to exist well before the onset of volatile biosynthesis. There were also different biosynthetic capacities for pulp and peel. Low aroma production in pre-climacteric fruit is apparently limited by the supply of precursors, which may be derived from the ethylene-induced enhancement of fruit respiratory metabolism.