Characterization of Volatile Organic Compounds of Opuntia Fruit Pulp. Changes in Cactus Fruit Aroma as a Consequence of Pulp Processing.

RODRIGUEZ, S.A.; DIAZ, SUSANA; NAZARENO M. A.

Palermo

Congreso; VIII International Congress on Cactus pear and cochineal; 2013

Universitá de Palermo

Among the cactus fruit sensorial properties mainly considered by consumers, color and flavor are of most importance. However, these properties may be modified due to food processing. Cactus pear flavor has been described in the literature as faint melon or cucumber-like aroma mainly constituted by alcohols and esters; 2-(E/Z)-2,6-nonadien-1-ol and 2-methylbutanoic acid methyl ester being the key aroma substances of the volatile organic compounds (VOC). The strongest flavor intensity was reported to be that of yellow cactus pear fruits, following that of red, and, finally, white ones. In this study, the chemical profile of fruit aroma was analyzed as well as its modification after pulp treatments. Three different Opuntia species from the province of Santiago del Estero, Argentina, have been selected. Cactus pear fruits have been collected at mature status, stored at 8°C and peeled just before analysis. Fruit pulps have been characterized. Total soluble solids, phenolic compound content, ascorbic acid and betalain levels were measured and antioxidant properties were determined. VOC were analyzed in the pulps immediately after fruit peeling and after applying three different processing treatments: short-term heating (bleaching), cooling at -18°C (freezing) for different storage times and long-term cooking (jam production). VOC extraction was performed by dynamic head space method. VOC composition was carried out by GC-MS analysis. At least 23 different constituents were identified in cactus pear fruit aroma. Slight differences in the aroma profiles were observed among Opuntia fruits. Moreover, new compounds, previously unreported, were also identified. Some aroma components did not persisted in fruit pulp after the short-term heating treatment. A similar behavior was found after jam production. The freezing storage of pulps allows keeping the flavors intact for at least 3 months. These are promising results considering the preservation of fruit sensorial properties in a time period far from the crop season.