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A goiaba é um fruto muito perecível. Assim, objetivou-se avaliar os efeitos de ceras à base de carnaúba na conservação pós-colheita de goiabas Pedro Sato sob condição ambiente. Utilizaram-se cinco ceras comerciais: Citrosol AK (18%), Citrosol M (10%), Fruit wax (18 a 21%), Meghwax ECF-100 (30%) e Cleantex wax (18,5 a 20,5%), as quais foram aplicadas manualmente, na proporção de 0,15 a 0,20mL por fruta. Frutas sem aplicação de cera foram utilizadas como controle. O delineamento experimental foi inteiramente casualizado com 6 tratamentos, 4 repetições e 5 frutas por parcela. As goiabas foram caracterizadas imediatamente após a colheita e avaliadas aos 2, 4 e 6 dias após a aplicação dos tratamentos. As ceras exerceram pouca influência nos teores de sólidos solúveis totais, acidez total titulável e ácido ascórbico, porém, foram eficientes em retardar o amadurecimento, reduzir a perda de massa e a incidência de podridões. A cera Meghwax ECF-100 apresenta potencial para utilização em goiabas, porém há necessidade de ser avaliada em maior diluição, para evitar alterações indesejáveis.

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Guava (Psidium guajava L.) is a tropical fruit exhibiting rapid post-harvest ripening. However, the physiological basis involved in the ripening process of guava is not totally clear, which makes it difficult to develop technologies to enhance fruit storability. Two experiments were carried out with the objective of determining the ripening behavior of 'Pedro Sato' guavas. In the first experiment, guava fruits at three maturity stages (I - dark green, II - light green and III - yellow-green) were stored at room temperature (23 ± 1°C and 85 ± 5 % RH). The respiratory rate, ethylene production, pulp and skin colours, and firmness were evaluated. In the second experiment, ethylene and 1-methylcyclopropene (1-MCP) were applied to guavas at the light green maturity stage and the ripening behaviour during storage at room temperature was studied. Fruits from all maturity stages showed a gradual increase in the respiratory rate and ethylene production. The intense changes in pulp and skin colours and in firmness preceded the maximum respiratory rate and ethylene production. 1-MCP reduced the rate of ripening, while the application of ethylene did not promote this process. These results do not permit the classification of 'Pedro Sato' guava as a traditional climacteric fruit.

RIPENING AND SENESCENCE OF PAPAYA WITH 1-METHILCYCLOPROPENEABSTRACT: Papaya (Carica papaya L.) fruits are highly perishable due the fast ripening after harvest. The search for techniques that extend the shelf life and reduce the post-harvest losses is desirable. In this study, papaya 'Sunrise Solo' fruits were harvested in two ripening stages (green and ripe) and treated with the competitive ethylene antagonist 1-methycyclopropene (1-MCP) at concentrations of 0, 30, 90 or 270 nL L -1 for 12 h at 20 o C followed by storage at room temperature (20 o C) during eight days. Application of 1-MCP (90 or 270 nL L -1 ) delayed degreening decay. Green fruits treated with 1-MCP (270 nL L -1 ) presented higher firmness in relation to control fruits. 1-MCP did not affect the soluble solids of fruits. The respiration rate and ethylene production were lower in fruits treated with 1-MCP (90 or 270 nL L -1 ) in both ripening stages. 1-MCP extended the shelf life of green fruits from four to six days and the shelf life of ripe fruits from two to four days. The 1-MCP was efficient to delay the ripening of papayas extending their shelf life. Key words: Carica papaya, 1-MCP, ethylene, firmness, storage INTRODUÇÃOO mamão (Carica papaya L.) é uma das frutas mais cultivadas do mundo, especialmente em áreas tropicais onde a temperatura média anual é de 25 o C (Simão, 1998). O Brasil é o maior produtor mundial de mamão, perfazendo cerca de 35% do total produzido.O mamão é um fruto climatérico cujas transformações resultantes do amadurecimento ocorrem rapidamente após a colheita do fruto fisiologicamente maduro, desencadeadas pela produção do etileno e aumento da taxa respiratória. Isso o caracteriza como um fruto bastante perecível em pós-colheita (Paull, 1993). Dada essa alta perecibilidade, o controle do amadurecimento é fundamental para o aumento na vida útil após a colheita, visando o mercado interno e exportação de frutas. Os principais fatores que depreciam a qualidade pós-colheita do mamão são o rápido amolecimento e a elevada incidência de podridões.A preservação do mamão em temperatura ambiente é desejável, uma vez que a quase totalidade da fruta comercializada ao nível de varejo, no Brasil, encontra-se sem refrigeração. A manutenção da qualidade do mamão nesta condição pode facilitar o transporte a longas distâncias e ampliar o período de comercialização. O etileno (C 2 H 4 ) está envolvido na aceleração do amadurecimento e senescência de frutos climatéricos. Em determinado estádio da maturação, o etileno se liga ao seu receptor na célula, um complexo protéico-enzimático, e desencadeia uma série de eventos que culminam com o amadurecimento e senescência do fruto

Harvest time is one of the main factors related to guava fruit postharvest losses. It is subjectively determined by fruit size and skin color, without any consensual standardization among the growers. The use of maturity indexes enables growers to know the ideal harvest time according to each market situation. The objective of this work was to determine the maturity indexes to identify the harvest time for guava fruit cv. Kumagai and Paluma. Skin color, fruit firmness, soluble solids, titratable acidity, ratio and ascorbic acid were analyzed. The most adequate maturity indexes for 'Kumagai' guava fruit were skin color and pulp firmness, while for 'Paluma' guava fruit, the best indexes were skin color, pulp firmness, titratable acidity and ratio.

Guavas cv.`Kumagai' were packed in several plastic materials and stored at 10°C and 85±90% relative humidity (RH) for 7, 14, 21 and 28 days (3 days at 25°C). The plastic materials studied were: multilayer co-extruded polyolephine ®lm with selective permeability (PSP), low-density polyethylene ®lm (LDPE), LDPE ®lm with mineral incorporation (LDPEm) and heat-shrinkable polyolephine ®lm (SHR). Guavas not packed were taken as control samples. The physicochemical characteristics of the fruits, O 2 and CO 2 transmission rates of the packaging materials and gas composition at the package headspace were evaluated. The LDPE ®lm, 69 mm in thickness, with the lowest permeability to both O 2 and CO 2 , led to anaerobiosis and high CO 2 concentration inside the packages and promoted physiological disturbances and changes in fruit¯avour. The SHR ®lm, 15 mm in thickness, was the most permeable to CO 2 and had quite high O 2 transmission, which modi®ed the inner atmosphere of the packages slightly. The fruits packed in this ®lm showed a poorer quality than the controls, possibly due to the heat produced during the shrinking of the ®lm. The LDPEm ®lm, 24 mm in thickness, was almost as permeable to CO 2 but had reduced O 2 transmission, promoting an atmosphere of equilibrium of 3% O 2 and 4.5% CO 2 . Fruits packed in this ®lm kept their skin colour and pulp ®rmness, suitable for consumption up to 14 days. The PSP ®lm, 35 mm in thickness, had the greatest O 2 transmission but just over half of the CO 2 transmission of LDPEm, promoting an atmosphere of equilibrium of 0.5% O 2 and 4.5% CO 2 inside the packages. Fruits packed in such packages kept their physicochemical characteristics up to 21 days.