Hyperbaric atmospheres in postharvest conservation of guava: physical-chemical and biochemical effects

Abstract

The postharvest shelf life of fruits and vegetables can be extended by adopting appropriate conservation techniques to maintain quality and reduce losses. Hyperbaric atmospheres have been suggested as an alternative for atmospheres with low O2 and high CO2 in storage of vegetables, due to problems of accumulation of acetaldehyde and ethanol. The hyperbaric pressure system allows the products to be exposed to atmospheres enriched in oxygen, above 21 kPa, with low energy consumption. Recent studies have shown the possibility of using hyperbaric pressures to delay the physiological mechanisms of maturation and senescence in plants, increase antioxidant compounds and induce natural resistance, extending the shelf life of vegetables. Guava stands out for its high acceptance for in natura consumption, attributed to its characteristics of flavor, aroma and nutritional value, however it has a short shelf life. To date, there are no studies in the literature on the physical-chemical and biochemical effects of hyperbaric atmospheres on guava conservation. Thus, the objective of the the work is to determine the influence of hyperbaric pressures on the qualitative, biochemical and molecular aspects of guavas in order to extend postharvest conservation. The experiments will be carried out in the Laboratory of Technology of Agricultural Products of FCAV-UNESP, Jaboticabal. 'Pedro Sato' guavas will be used at the stage of physiological maturation, coming from commercial orchards of the region. Hyperbaric treatments will be applied in guavas at pressures of 100 (control), 200, 400, 600, and 800 kPa, at the temperature of 12ºC. Fresh weight loss, firmness, skin and pulp color, respiratory rate, ethylene production, soluble solids content, titratable acidity, ascorbic acid, total antioxidant activity, total extractable polyphenols, lycopene, antioxidant, hormonal and cell wall enzymatic activity, incidence of rot and analysis of gene expression will be assessed. (AU)