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IntroductionAroma is one of the most important factors in sensory quality identity for fruits and vegetable products. Food aroma can be understood and identified by its volatile chemical compounds content. These volatiles are sensed and the aroma perceived by olfactory sensory receptors either when food are tasted or by its smell exhaled from a distance (NOBREGA, 2003).Volatile compounds have an important role in fruit juice sensory quality, particularly when it is heat treated and need to be stored ISMAIL;ASKAR, 1988). Qualitative and quantitative analyses of aroma compounds are needed in monitoring product quality and for aroma developing in fresh and processed products (SONG et al., 1997).Yen and Lin (1999), studying heat treatment, 95 °C/5 minute, in guava juice, detected a decrease in the volatile compounds content as compared to fresh product; however, there was no important effect of storage time on the volatile concentration up to 60 days under refrigeration at 4 °C. Esters and alcohols had higher concentrations than those of the other volatile compounds. ResumoNéctares de goiaba foram formulados para 10, 12 ou 14 ºBrix. Benzoato de sódio, 500 mg.kg -1 , foi usado como conservante. O Brix foi ajustado usando xarope saturado de sacarose. O néctar foi pasteurizado a 85 °C/42 segundos, em trocador de calor tubular e envasado, a quente, em garrafas de vidro branco de 500 mL. Os produtos foram estocados à temperatura ambiente (25 ± 5 o C) e sob refrigeração (5 ± 2 o C), expostos à luz fluorescente e analisados um dia após processamento (tempo zero) e aos 40, 80 e 120 dias de estocagem. Oito compostos foram identificados e quantificados por Cromatografia Gasosa (CG) -Espectrometria de Massa (EM): hexanal, (E)-hex-2-enal, 1-hexenol, (Z)-hex-3-enol, acetato de (Z)-hex-3-enila, acetato de 3-fenilpropila, acetato de cinamila e ácido acético. O efeito do processamento térmico na concentração de compostos voláteis não foi significativo, exceto um decréscimo na concentração de hexanal (p = 0,0001) e acetato de (Z)-hex-3-enila (p = 0,0029). Observou-se maior decréscimo no teor dos ésteres (Z)-hex-3-enila e acetato de 3-fenilpropila durante a estocagem. O acetato de cinamila apresentou maior decréscimo de concentração após a estocagem. A refrigeração apresentou melhor efeito na estabilidade dos teores de voláteis, principalmente os ésteres. Palavras-chave: néctar de goiaba; compostos voláteis; GC; GC/MS; processamento térmico; estocagem. AbstractGuava nectars were formulated for approximately 10, 12, or 14 o Brix, with 40% guava pulp. Sodium benzoate, 500 mg.kg -1 was used as preservative. The Brix value was adjusted with saturated sucrose syrup. The guava nectar was pasteurized (85 o C/42 seconds) in tubular heat exchanger and then hot filled in 500 mL white glass bottles. The products were stored either at room temperature (25 ± 5 o C) or refrigerated (5 ± 2 °C) under fluorescent light exposure and analyzed on the day after processing (time zero) and also 40, 80, and 120 days of storage. Eight compounds were identif...