Ana Cecilia Silveira

Quality of tomato slices disinfected with ozonated water

Fresh-cut industry needs novel disinfectant to replace the use of chlorine. Ozone is one of the most powerful oxidizing agents and is applied in gaseous or aqueous form for sanitation purposes. However, the strong oxidative effect could affect the nutritional and sensorial quality, in particular, when time of washing is extended. For that reason, the overall impact of ozonated water (0.4 mg/L) dipping applied during 1, 3 and 5 min compared to control washed in water during 5 min was studied in tomato slices stored during 14 days at 5 ℃. According to the results, ozonated water treatment of 3 min achieved the best firmness retention, microbial quality (mesophilic, psychrotrophic and yeas load) and reduced the consumption of fructose and glucose. The use of ozonated water did not affect the total acidity, pH, total solid soluble, organic acid as ascorbic, fumaric or succinic acid and the sensorial parameters, which were only affected by storage time. However, the poor appearance, aroma and overall quality obtained in all treatments prevented shelf life of 14 days and the quality at acceptable levels was established in 10 days at 5 ℃. It is recommended to wash tomato slices with 0.4 mg/L ozonated water for 3 min only. Extending treatment duration did not improve the microbiological quality, possibly due to the extra time permitting the ozone to react with other components of the fruit tissue, undermining the antimicrobial benefits.

Determinación de algunos atributos de calidad de la variedad Fuji y sus mutantes al momento de cosecha

Many studies have shown that fruits and vegetables are not only source of energy and nutrients, but also source of important components as phytochemicals which help preventing cancer, cardiovascular and neurodegenerative diseases. The increasing apple production has a direct effect on the production of apple processed products. Therefore, the knowledge about healthy substances as polyphenols and anthocyanins is important in order to determine the potential use of apple fruits for processing industry. The objective of this work was to physicochemically characterize three apple cultivars, Fuji, Fuji Kiku, and Fuji Suprema. The characterization was based on pulp firmness, titrable acidity (TA), total soluble solids (TSS), iodine index, skin color, polyphenols, anthocyanins, reduced sugars, and vitamin C. According to the results, the Fuji Kiku cultivar had higher values of pulp firmness, AT, TSS and vitamin C. The Fuji Suprema cultivar showed more intense red color and higher levels of anthocyanins. There were no differences on polyphenols and reduced sugars.

The suitability of three Galia melon cultivars and different types of cuts for the fresh-cut industry

BACKGROUND Melons (Cucumis melo L.) are widely cultivated in Mediterranean countries. For fresh-cut melon elaboration, factors such as type of cultivar and cut have a significant impact on final product quality. The quality parameters from long, medium and short shelf-life Galia melon cultivars, cut into different shapes such as slices, trapezoids and cylinders and stored up to 10 days at 5 °C, were evaluated in order to learn the suitability of these cultivars and type of cut for minimal processing. RESULTS In general, long-life melon cultivar had a low respiration rate and ethylene emissions, and high tissue firmness, but low levels of glucose, fructose, vitamin C and flavor rating by consumers. However, despite having higher metabolic activity and susceptibility to microbial spoilage, the short shelf-life cultivar melon had higher firmness retention. This cultivar was characterized by its richness in glucose, fructose and vitamin C, and its sensory quality (flavor) was highly valued. In general, the medium cultivar had an intermediate behavior between long and short cultivars but without their positive attributes. As a consequence of the most intense damage, the cylindrical shape had higher metabolic activity, susceptibility to microbial spoilage and reduced appearance. CONCLUSIONS In the long and medium-life cultivars studied, low flavor was the limiting factor to extend the shelf-life of fresh-cut melon while for the short-life cultivar the limiting factor was its susceptibility to bacterial growth. Cut types such as cylinders should be avoided.

Oxidative enzymes and functional quality of minimally processed grape berries sanitised with ozonated water

Thompson Seedless (TS) and Black (BS) grapes sanitised with 2, 4, 6, 8 mg L 1 O3 or NaOCl (100 mg L ) were stored 21 days at 5 °C. Ozonated water stimulated the respiration rate, especially after 5 days of storage, and increased superoxide dismutase and catalase activity compared to NaOCl-sanitised grapes. Total polyphenol content (TPC) was 23–50% higher in TS and 18.5–28% higher in BS samples sanitised with ozonated water. Twofold higher total antioxidant capacity (TAC) was registered in TS at all of the evaluated O3 doses while the doses of 6 and 8 mg L 1 increased TAC by 19–30% in BS. The use of ozonated water as a sanitising method, especially at 6 and 8 mg L 1 doses, improved the functional quality and maintained low microbial counts on fresh-cut grapes being a good alternative for the industry.

Uso de aditivos y métodos físicos para mantener la calidad de los productos de IV gama o mínimamente procesados

Los productos de IV gama o minimamente procesados son los sometidos a una serie de operaciones unitarias, tales como pelado, cortado, lavado y desinfeccion, entre otros, que modifican su apariencia pero que mantienen vivos sus tejidos. El mantenimiento de la calidad organoleptica nutricional y funcional de los productos de IV gama o minimamente procesados hace necesario reducir procesos de deterioro como el pardeamiento enzimatico y el ablandamiento. El control de estos procesos se realiza a traves de aditivos quimicos. En el caso del pardeamiento enzimatico se emplean, entre otros, acidulantes y agentes quelantes, mientras que las sales de calcio son utilizadas para el mantenimiento de la firmeza. Sin embargo, la tendencia actual de reducir la utilizacion de aditivos quimicos genera la necesidad de desarrollar metodos alternativos para el control de los procesos de deterioro, cobrando importancia los metodos fisicos, entre los que se encuentran los tratamientos termicos y las radiaciones ionizantes y no ionizantes (UV-C, microondas, ultrasonido). Por otra parte, tanto los metodos quimicos como los fisicos poseen una actividad limitada. Su combinacion determina efectos sinergicos (tecnologias de obstaculos) que conducen a una mayor preservacion de la calidad. En este trabajo se aborda el uso de los aditivos quimicos y los tratamientos fisicos, tanto solos como combinados, para controlar el ablandamiento y el pardeamiento enzimatico en productos de IV gama.