791 Postharvest Conservation of Mature-Green and Ripe ‘Paluma’ Guava Stored at Two Temperatures C.M.A. Morgado, J.F. Durigan, M.F.B. Durigan and V.G. Lopes UNESP, Universidade Estadual Paulista, FCAV, Technology Department Via de Acesso Prof. Paulo Donato Castellane, s/n, 14.884-900 Jaboticabal, S.P. Brazil Keywords: Psidium guajava, refrigeration storage, harvest stage Abstract This work aimed to establish the importance of maturation and ripeness stages and the use of refrigeration for the conservation of ‘Paluma’ guavas. Fruit picked at the mature-green and ripe stages were stored at ambient conditions (21°C and 85% RH) and also at 10°C (85% RH). The fruit were evaluated every 2 or 3 days for weight loss, appearance, decay, color, firmness, soluble solids, titratable acidity, ascorbic acid, total polyphenols extractable content and total antioxidant activity. The fruit stored at 21°C had higher weight loss than those stored at 10°C. Mature-green guavas at 21°C remained in good quality for 6 days, but at 10°C, the preservation period increased to 15 days. Ripe fruit were preserved for 4 days at 21°C, which was extended with refrigeration to 6 days. Mature-green fruit at 21°C had decay in 6 days; while at 10°C decay happened in 18 days. The peel color of mature-green fruits, at 21°C, showed increasing values of luminosity, indicating that its color became lighter (change from green to yellow) and at 10°C it showed constant values until the end of storage. Pulp firmness of mature-green fruit declined during storage as a result of ripening. In ripe fruits such reduction occurred more slowly, since they were softer. The color of the pulp became intense red for mature fruits. Soluble solids were lower in ripe fruit at 21°C, while in mature fruits at 10°C, it increased. The titratable acidity increased in fruits stored at 10°C. The fruits kept at 21°C and the mature guavas kept at 10°C showed no changes in ascorbic acid content. The ripe fruit at 10°C maintained their ascorbic acid levels. Mature guavas, stored at 10°C, had the longest shelf life and higher contents of soluble solids and titratable acidity, with no changes in total polyphenols extractable content and total antioxidant activity. INTRODUCTION Guava (Psidium guajava L.) is a native fruit from tropical America. In Brazil it is distributed throughout the whole country. It is an important asset from the social and economical view, especially for São Paulo State, which is responsible for more than 60% of the national volume production of this fruit. There are different cultivars which are destined for fresh consumption, with white or red pulp. The red pulp guavas are more popular and are used for both fresh market and processing (Souza et al., 2009). The guava is excellent for human consumption because of its good amounts of vitamin C, carotenoids, potassium, fiber, calcium and iron, besides having low caloric content and great antioxidant potential (Meltzer, 1998). The nutritional qualities made this fruit merit special attention for fresh consumption and for the development of new products (Durigan et al., 2009). In Brazil, the development of quality for fresh fruit in the market has increased a lot. This is due to changes in the Brazilian’s dietary habits, which led to people to pay more attention to other quality parameters, such as antioxidants, which are present in large quantities in guava (Souza, 2001). The objective of this work was to establish the importance of maturation stage and the use of refrigeration, for the conservation of ‘Paluma’ guavas. Proc. XXVIII th IHC – IS on Postharvest Technology in the Global Market Eds.: M.I. Cantwell and D.P.F. Almeida Acta Hort. 934, ISHS 2012