Ozone as a phytosanitary agent in the postharvest conservation of arracacha

Abstract

Arracacha roots (Arracacia xanthorrhiza Bancroft) were immersed in water through which ozone was bubbled to assess the control of bacteria of the genus Erwinia. In addition to a visual analysis of the roots, the activities of the pectinolytic enzymes pectin methylesterase and polygalacturonase were evaluated during storage, and also the physicochemical characteristics (mass loss, colour variation, sugar and starch contents). The roots were immersed in ozonized water (1.52 mg L^-1) for periods up to 30 min. They were then placed in a climatic chamber and evaluated for 10 days. There was no apparent visual difference amongst the treatments. However the roots treated with ozone for 30 min showed lower specific activity of the pectin methylesterase enzymes. There was a linear effect on total soluble sugars and mass loss and a quadratic effect on reducing and non-reducing sugars, only significant for storage. Immersion of the arracacha roots in water through which ozone was bubbled for 30 min was not sufficient to control bacteria of the genus Erwinia. Under the conditions adopted in this work, ozonation caused no changes in the mass loss, the starch, total soluble sugars, or reducing and non-reducing sugar contents or in the colour variation of the arracacha roots.

Keywords:
Arracacia xanthorrhiza Bancroft; Erwinia; Postharvest quality; Pectin methylesterase; Polygalacturonase