Maria Cecília de Arruda Palharini

Tratamentos alternativos no controle da antracnose e sobre a qualidade de goiabas ‘Pedro Sato’

Um dos grandes problemas na comercializacao de goiabas e a incidencia de doencas pos-colheita que coincide com o amadurecimento dos frutos. Avaliou-se o efeito de produtos alternativos [fosfito de potassio, cloreto de calcio, fecula de mandioca, 1-metilciclopropeno (1-MCP), etanol seguido de dicloro s. triazinatriona sodica dihidratada (etanol+cloro)] e de tratamento hidrotermico, isoladamente e em associacao, no controle da antracnose e nas caracteristicas fisico-quimicas de goiabas ‘Pedro Sato’. Os tratamentos foram realizados em goiabas naturalmente infectadas, em tres estadios de maturacao, armazenadas a 22 ou 25oC por oito dias. A incidencia da antracnose foi avaliada pelos sintomas visuais e observacao dos sinais do patogeno em microscopio optico e os parâmetros fisico-quimicos avaliados foram cor da casca, firmeza da polpa, perda de massa fresca, solidos soluveis, acidez titulavel e acido ascorbico. As associacoes de tratamentos etanol+cloro/fecula, hidrotermico/fecula e etanol+cloro/1-MCP reduziram a antracnose nos tres estadios de maturacao, em pelo menos algum periodo do armazenamento, promovendo um maior periodo de conservacao dos frutos, com um atraso de dois a quatro dias no aparecimento da doenca. A manutencao da qualidade das goiabas com as associacoes de tratamentos foram evidenciadas pelo atraso na mudanca de coloracao da casca e menor reducao na firmeza da polpa, com destaque para etanol+cloro/1-MCP. Observou-se correlacao positiva entre a incidencia da antracnose e o estadio de maturacao, expresso pela cor da casca do fruto. A maior eficiencia das associacoes de tratamentos no controle da antracnose relacionou-se diretamente ao atraso no amadurecimento dos frutos, evidenciado pelos parâmetros cor da casca e firmeza da polpa.

QUALIDADE DE GOIABAS ‘PEDRO SATO’ EM FUNÇÃO DE TRATAMENTOS ALTERNATIVOS EM PÓS-COLHEITA

This study aimed to evaluate the effect of alternative products and thermotherapy, singly and in combination, on the physicochemical quality and controlling decay of ‘Pedro Sato’ guavas. Initially the treatments with calcium chloride, potassium phosphite, 1-methylcyclopropene (1-MCP), cassava starch, ethanol followed by chlorine (ethanol+chlorine) and thermotherapy were evaluated for eight days of fruits storage at 22°C. In a second step, four treatments were selected (cassava starch, 1-MCP, thermotherapy and ethanol+chlorine) and evaluated the association of two, applied sequentially, during eight days of fruits storage at 25 °C. The 1-MCP treatment and cassava starch were the most effective in keeping the physicochemical quality of ‘Pedro Sato’ guavas, slowing the weight loss, change of skin color, and contributing to firmness retention. Greater reduction in fruit rot was found in thermotherapy, cassava starch and 1-MCP treatments. The associations of 1-MCP/cassava starch and thermotherapy/cassava starch were the most effective treatments to maintain the quality of ‘Pedro Sato’ guavas, slowing the weight loss, change of skin color, and loss of firmness. Association treatments reduced incidence of decay, especially the ethanol+chlorine/thermotherapy and thermotherapy/cassava starch that were more efficient until the fourth day of storage. The rots incidence correlated with parameters of skin color and firmness for most association treatments. In general, it is recommended the thermotherapy/cassava starch for guavas stored at 22-25oC as a way of maintaining the physicochemical quality and delaying at least two days the symptoms of decay.

Conservação de vagem minimamente processada em embalagem com atmosfera modificada passiva

O trabalho teve como objetivo avaliar a influencia da embalagem com atmosfera modificada na conservacao da qualidade de vagem minimamente processada, visando principalmente minimizar o escurecimento enzimatico e a deterioracao microbiana. O trabalho consistiu em um teste preliminar e um experimento final. No teste preliminar, as vagens foram acondicionadas em diferentes embalagens (bandeja de PP; PVC 20 µm; PEBD 33 e 52 µm; PP 32 e 51 µm; filme laminado BOPP/PEBD 66 µm) e armazenadas a 10 °C por quatro dias. No experimento final, as vagens foram acondicionadas em tres diferentes tipos de embalagens e armazenadas a 5 °C por sete dias. A qualidade do produto foi avaliada periodicamente por meio de analises fisicas, quimicas, bioquimicas, microbiologicas e sensoriais. O delineamento experimental foi inteiramente casualizado em esquema fatorial (tratamentos × tempo de armazenamento) com tres repeticoes. Os resultados obtidos foram submetidos a analise de variância e comparacao de medias pelo teste de Tukey (5%). Durante armazenamento a 10 °C, ocorreu anaerobiose dentro das embalagens de PVC, polietileno, polipropileno e filme laminado, contendo vagem minimamente processada. As embalagens de PVC e microperfurada a laser (Xtend-815-BAS-14) contribuiram para manutencao da qualidade durante sete dias de armazenamento a 5 °C. Recomenda-se a utilizacao de agua resfriada a 5 °C nas operacoes de enxague e sanitizacao e o armazenamento a 5 °C. A modificacao da atmosfera nas embalagens de vagem minimamente processada, em virtude da utilizacao da embalagem de PVC e da embalagem com filme microperfurado a laser, minimizou o escurecimento e a proliferacao microbiana.

Adubação nitrogenada sobre a ocorrência de doenças em pós-colheita do morango

This study evaluated the effect of nitrogen doses on postharvest diseases of strawberry cultivars Camino Real, Festival and Oso Grande. The nitrogen in urea formulation was evaluated at the recommended dose (100%) based on the official recommendation to the culture, and 3 lower doses (83, 67 and 50% of recommended), considering the fertilization at planting and cover applications. Fruits were harvested and weighed at 75% of its surface with a bright red color. Twelve fruits per plot were sampled in 3 collections from the second flowering and assessed for disease incidence during five days of storage at 25°C and 85% relative humidity. The identification of disease was made daily, based on symptoms and pathogen signs. There was no effect of nitrogen doses on yield and incidence of postharvest diseases, expressed as area under the disease progress curve (AUDPC). Increased average production was observed in cultivars Festival and Oso Grand. The overall incidence of disease among the cultivars did not differ significantly. Gray mold was the main disease, affecting more than 30% of fruits, followed by Rhizopus and yeast rot.

Doenças pré e pós-colheita em variedades de manga cultivadas em sistema orgânico

The choice of mango variety to be used in an organic production system should be related with phytosanitary limitations, thus the objective of the present study was to evaluate the behavior of mango varieties cultivated in organic system in relation to the diseases powdery mildew, flower malformation and post harvest diseases. Seventeen mango varieties were evaluated, cultivated in organic system, planted in experimental design in randomized blocks, with 17 treatments and six repetitions. The incidence of flower malformation was determinate through the observation and count of the plants with symptoms of the disease. To evaluate the severity of malformation and powdery mildew were used scales of notes. For the characterization of the post-harvest diseases the severity of the anthracnose was visually evaluated after 1, 4, 7 and 10 days of the fruits harvest. After obtaining the data, the area under the disease progress (AUDP) was calculated. It can be concluded that the Rosa variety is very resistant to the flower malformation; the varieties Bourbon, Espada Stahl, Ataulfo and Beta can be classified as resistant and the variety Lita is the most affected for the disease among the studied varieties. The varieties Omega and Rocha can be considered as resistant to the powdery mildew and the varieties Espada Ouro de Itaparica, Imperial, Lita, Rosa and Uba are the most susceptible. The occurrence of post-harvest diseases was elevated in most of the mango varieties, being the anthracnose the most frequent one, affecting the fruits starting from the first day of storage, followed for the stem-end rot with important occurrence at the end of the storage. The varieties Bourbon Vermelha and Espada Stahl stand out for not presenting stem-end rot and smaller anthracnose severity.

Dynamics of gas levels inside packages containing minimally processed Pera orange

The purpose of this study was to evaluate the changes in concentrations of O2 and CO2 inside packages of minimally processed Pera orange. Previously selected oranges that were washed, sanitized, and chilled were peeled using hydrothermal treatment (immersion of fruits in water at 50 °C for 8 minutes). The peeled oranges were then packed in five different plastic packages under passive and active modified atmosphere (5% O2 + 10% CO2 + 85% N2). The fruits were stored at 6 °C and 12 °C. The package headspace gas composition was evaluated for twelve days at 6 °C and nine days at 12 °C. The polypropylene film (32 µm) promoted modified atmosphere similar to that initially injected (5% O2 + 10% CO2 + 85% N2) at 6 °C and 12 °C. With regard to the atmosphere modification system, the injection of a gas mixture anticipated achieving an equilibrium atmosphere inside the packages at 12 °C. At 6 °C, the gas composition inside the packages was kept close to that of the injection, but the equilibrium was not verified.