Uso de embalagens plásticas e cobertura de quitosana na conservação pós-colheita de lichias

Objetivou-se avaliar a efetividade da atmosfera modificada, através de embalagens plásticas e coberturas de quitosana, na conservação pós-colheita de lichias. O delineamento estatístico foi o inteiramente casualizado, disposto em esquema fatorial 5 x 7, com 3 repetições, onde o primeiro fator corresponde aos tratamentos: Testemunha; Bandejas rígidas de poliestireno revestidas com filme poliolefínico de 0,015mm (PD955); Bandejas rígidas de polietileno tereftalato (PET); Bandejas de poliestireno recobertas com filme de cloreto de polivinila (PVC) de 0,014mm; e Imersão em quitosana a 0,5%. O segundo fator foi o tempo de armazenamento, 0 (inicial); 4; 8; 12; 16; 20 e 24 dias, a 5 ºC (94 %UR). Cada parcela foi composta por 8 frutos, sendo que os tratados com quitosana foram contidos em bandejas rígidas de poliestireno, sem filme. Os resultados obtidos permitiram concluir que a proteção com filmes plásticos reduziu significativamente a perda de massa por lichias mantidas sob refrigeração, com redução na intensidade do escurecimento dos frutos. O tratamento com quitosana a 0,5%, em ácido tartárico a 10%, pH 0,8, mostrou-se efetivo na manutenção da coloração vermelha e na prevenção ao escurecimento, conservando a aparência dos frutos

Role of 1-MCP in regulating 'Kensington Pride' mango fruit softening and ripening

Ripening of mango fruit is characterized by softening of flesh which limits its shelf life. 1-MCP is nontoxic gas that delays fruit softening and improves quality of several fruit. Therefore, the role of 1-MCP in regulating fruit softening and quality of ‘Kensington Pride’ mango was investigated. Physiological mature fruits treated with 1-MCP (1 mL L-1), ethylene (10 mL L-1) or 1-MCP + ethylene for 12 h at ambient condition (20 ± 1 C). Untreated (control) as well as treated fruits were allowed to ripe at ambient temperature (20 ± 1 C) for 10 days. Ethylene production, respiration rate and other fruit ripening parameters were determined periodically. Climacteric peaks of ethylene production and respiration rate were significantly supressed by 1-MCP application as compared to ethylene-treated and control fruit. Exogenous application of ethylene accelerated the development of fruit colour, fruit softening with increased activities of exo-PG, endo-PG and EGase enzymes in the pulp tissues. Whereas, activities of fruit softening enzymes were significantly delayed and/or suppressed in 1-MCP-treated fruit. 1-MCP-treated fruit showed improved rheological properties (i.e., firmness, springiness and stiffness), decreased level of citric acid, malic acid, succinic acid, total organic acids, total sugars and sucrose than other treatments. 1-MCP inhibited the activities of fruit softening enzymes which consequently delayed the ripening and ripening related changes in ‘Kensington Pride’ mango