Influence of pH on the efficacy of ozonated water to control microorganisms and its effect on the quality of stored strawberries (Fragaria x ananassa Duch.)

Abstract

Influence of pH on the efficacy of ozonated water to control microorganisms and its effect on the quality of stored strawberries (Fragaria x ananassa Duch.) May 12, 2017 and approved in July 24, 2017 ABSTRACT Ozonation has been proposed as an alternative for the post-harvest treatment of plant products. Therefore, the objective of this study was to evaluate the influence of the pH on the efficacy of ozonated water to control microorganisms and to determine the possible effects of ozone on the quality of stored strawberries. To evaluate the influence of pH on ozonated water in Portola variety strawberries, the strawberries were divided into six batches. Three batches were exposed to ozonated water and three batches were exposed to nonozonized water with different pH levels and an immersion time of 5 min. The pH values used were 3.0, 6.5 and 8.7. After the ozonation, the fruits were stored in a cold chamber at 5 °C for 6 days, and analyses were performed every two days. A completely randomized design was adopted using a 6x4 factorial scheme with three replications. The aerobic mesophiles, molds and yeasts, total coliforms and Escherichia coli were quantified, and the presence of Salmonella spp. was assessed. For the quality evaluation, the mass loss, titratable acidity (TA), pH, soluble solids (SS), SS/TA ratio and color were analyzed. The pH of the water was verified to influenced the effectiveness of the ozonated water to control the aerobic mesophiles and molds and yeasts. The ozonated water can retard fresh mass losses and maintain the pH, soluble solids, titratable acidity, SS/TA ratio and color variables. Index terms:Ozone; microbiological quality; qualitative changes. RESUMOA ozonização tem sido proposta como alternativa para o tratamento pós-colheita de produtos de origem vegetal. Então, objetivou-se com este trabalho avaliar a influência do pH na eficácia da água ozonizada no controle de microrganismos e determinar possíveis efeitos na qualidade de morangos armazenados. Para avaliar a influência do pH na água ozonizada em morangos da variedade Portola, dividiuse os morangos em seis lotes, sendo três lotes expostos a água ozonizada e três lotes em que a água não foi ozonizada, adotando-se diferentes valores de pH e tempo de imersão de 5 min. Os valores de pH adotados foram 3,0, 6,5 e 8,7. Depois da ozonização, os frutos foram armazenados em câmara fria a 5 °C por 6 dias, sendo realizadas análises a cada dois dias. Adotou-se delineamento inteiramente casualizado em esquema fatorial 6x4, com três repetições. Quantificaram-se os aeróbios mesófilos, bolores e leveduras, coliformes totais e Escherichia coli e verificou-se a presença de Salmonella spp. Na avaliação da qualidade, analisaram-se perda de massa, acidez titulável (AT), pH, sólidos solúveis (SS), relação SS/AT e cor. Verificou-se que o pH da água influenciou a eficácia da água ozonizada no controle de aeróbios mesófilos e bolores e leveduras. A água ozonizada foi capaz de retardar a perda de massa fresca e manter os níveis de pH, sólidos solúveis,...

Ozone washing decreases strawberry susceptibility to Botrytis cinerea while maintaining antioxidant, optical and sensory quality

“…Contradictory results were reported in the literature on physicochemical parameters of strawberries as affected by different ozone doses in aqueous phase and/or storage conditions. Ferreira, de Alencar, Alvez, Ribeiro & da Silva (2017) found that ozonisation in distilled water at pH 3.0 and pH 8.7 for 5 min (0.11 and 0.04 mg.L −1 , respectively) maintained TSS values of strawberries cv. Portola throughout refrigerated storage while control fruit showed decreasing values.…”

Response of root-knot nematode Meloidogyne javanica to ozone

“…Megahed, Aldridge and Lowe (2018) proved the antimicrobial capacity of aqueous and gaseous ozone through manure residues disinfection in livestock farms. Also, ozone has led to a prolonged shelf life of fruits and vegetables by reducing the populations of pathogenic microorganisms in post-harvest diseases (Ferreira et al, 2017;Sarig et al, 1996). Ozone micro-bubbles (aqueous ozone) were used as a disinfecting approach against phytopathogens in hydroponic culture solutions (Kobayashi et al, 2011).…”