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The effect of aqueous ozone at different doses on fungal incidence, microstructure, mechanical properties, and weight loss of blueberry fruit (Vaccinium corymbosum, cv. O’Neal) throughout 20 days of storage at 4 ± 1 °C was studied. Fruits were exposed to 10 and 18 mg O3 L-1 in a bubble column for different periods of time ranging from 10 to 30 min. Native mycobiota and Botrytis cinerea incidences were reduced by ozone exposure. After 15 days of storage, exposure to 18 mg O3 L-1 for 10 and 20 min reduced the percentage of infected fruit in ~ 34 and 40 %, respectively, when compared with untreated blueberries. Slight but no significant differences among ozone treatments were observed for native mycobiota and B. cinerea incidence. Stiffness, rupture force, and mechanical work required to break the fruit epidermis were not significantly affected by ozone treatments. The effect of ozone treatment on weight loss of blueberries was dose-dependent and was partially correlated with microstructural changes induced by ozone: disruptions in outer tangential and epidermal cell walls and alteration of the cuticle. Exposure times beyond 15 min significantly increased weight loss and did not achieve greater fungal inhibition with respect to 10- and 15-min ozonized fruit. Thus, the ozone dose to be selected would be limited by the negative effect on weight loss. Exposure to 18 mg O3 L-1 for 10 min would be the most suitable treatment to reduce fungal decay without causing an excessive loss of weight along cold storage.

The effect of different doses of UV-C light (5.3, 8.3 and 11.4 kJ/m2) on native mycobiota and Botrytis cinerea incidence, micro and ultrastructure, biomechanical properties and weight loss of blueberry fruit cv. O'Neal during 20 days of storage at 8 ± 1 °C was evaluated. Decay incidence was significantly reduced by all UV-C light doses for both, native mycobiota and inoculated B. cinerea. The highest UV-C dose studied (11.4 kJ/m2) was the most effective indelaying the onset of fungal and B. cinerea infection (6 and 4 days, respectively). UV-C irradiation caused some distinctive changes in fruit structure characterized by redistribution, alteration and partial removal of epicuticular waxes, reinforcement of epicarp cell walls, and modifications in the cuticle. Biomechanical parameters were not affected by UV-C treatments excepting at day 15 where irradiated samples showed higher values of rupture force (FR) and deformation (D). Structure changes partially explained the significant increase in weight loss, FR and D values in irradiated fruit after 15 days of storage. UV-C irradiation could be an alternative for delaying and reducing fungal infection. However, postharvest shelf-life of irradiated blueberries could be limited by the negative effect on weight loss., Blueberry, UV-C dose, B. cinerea infection, Structure, Weight loss.

Changes in the epidermis structure (micro, ultra, and nano), mechanical properties, and surface color of Solanum licopersicum L. fruits (cherry tomatoes) due to hydrogen peroxide (HP) and high-power ultrasound (US) treatments were examined. Both treatments induced small alterations in the epicuticular waxes, the cuticular membrane, and the epidermal and subepidermal cells. Plasmolysis of subepidermal cells, slight epicarp compression, and dense cellulose microfibrils pattern in the non cutinized cellulose layer were documented after US. Looser cellulose microfibrils pattern in the cutinized and non cutinized cellulose layer was detected after HP exposure. Main nanostructure alterations in the cellulose domain affected the morphology and size of cellulose aggregates and nanofractures of cellulose layer in treated fruits. US treatment decreased a*, b*, and chroma values by 10, 5, and 7% and increased L* and hue angle by 2.5 and 3%, respectively, as compared to raw fruits. These small but significant differences were attributed to the disruption of the wax layer; color became brighter, more vivid, and more orange. Treatments slightly affected puncture parameters; the rupture force decreased from 14.8 N to 14.1 N and 13.8 N; the penetration probe at the rupture point increased from 7.6 mm to 7.7 mm and 8.0 mm and the mechanical work decreased from 48.7 mJ to 48.3 mJ and 44.4 mJ in raw fruits and after HP and US exposure, respectively. The mechanical response could be partially explained by the alterations in the micro, ultra, and nanostructure of the tissues. The low impact of US and HP treatments on mechanical and color characteristics would indicate their potential for cherry tomatoes decontamination. Fil: Fava, Joaquín. Secretaría de Ambiente y Desarrollo Sustentable; Argentina Fil: Nieto, Andrea Bibiana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias; Argentina Fil: Hodara, Karina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Métodos Cuantitativos y Sistemas de Información; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Alzamora, Stella Maris. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Castro, María Agueda. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina

El puré deshidratado de mandioca es un producto obtenido a partir de la raíz de mandioca (Manihot esculenta Crantz), mediante un proceso tecnológico sobre raíces limpias y peladas. Será utilizado como tal o como materia prima para la producción de pastas alimenticias o mezclas para pastas. El conocimiento de las propiedades, fisicoquímicas y funcionales del puré deshidratado de mandioca y del producto reconstituido constituye información fundamental para poder analizar las actuales y futuras aplicaciones tecnológicas. En este trabajo se estudió la influencia de la temperatura sobre el proceso de rehidratación y el efecto del tamaño de partícula sobre la cinética adsorción de agua de purés deshidratados de dos variedades de mandioca, ‘Pomberi’ y ‘Concepción’. El efecto de la temperatura fue evaluado mediante los Índices de Adsorción de Agua a tres temperaturas (30, 40 y 50 ºC). La cinética de adsorción de agua fue estudiada con los modelos de Pilosof y Exponencial. El Índice de Adsorción de Agua aumentó con el incremento de la temperatura en los purés de las dos variedades de mandioca. Los modelos de Pilosof y Exponencial describieron adecuadamente la cinética de adsorción de agua. La velocidad de adsorción de agua fue mayor en el puré con las partículas de menor tamaño.