Vitamin C levels of selected Philippine indigenous berries as affected by fruit maturity and processing treatment

The Philippines as a tropical country is home to several indigenous berries that offer enough supply of health-promoting bioactive compounds like vitamin C. Vitamin C is an important micronutrient in the human diet that is usually supplied by fruits and vegetables. The amount of this vitamin in different products varies depending on the species, variety, maturity, processing, and other conditions. In this study, the vitamin C contents of selected Philippine indigenous berries such as bignay and lipote were evaluated as affected by fruit maturity and processing treatment. Fruits of two bignay (Antidesma bunius (Linn.) Spreng), varieties, ‘Common’ and ‘Kalabaw’, as well as of lipote (Syzygium polycephaloides (C. B. Rob.) Merr.), at three maturity stages (unripe, half-ripe, and fully ripe) were acquired in Laguna, Philippines. Samples were subjected to two processing treatments: blanched (90 ± 5 °C, 2 minutes) and steamed (105 ± 5 °C, 5 minutes), while control samples did not undergo processing treatment. The flesh and seeds were separated, lyophilized, extracted, and subjected to quantification of vitamin C using reversed-phase high performance liquid chromatography. Results showed that the vitamin C levels of both fruits were significantly affected by maturity, processing, and their interaction (P < .05). In general, a concomitant increase in vitamin C content was noted as fruit maturity progressed for both flesh and seeds (0.3 to 1.7-fold increase). Lipote seeds on the other hand, had decreased vitamin C content as maturity progresses (0.6-fold decrease). Moreover, blanching the fruits resulted in the highest retention of vitamin C in the fruit samples (247% at most). The general findings of this study indicated that the utilization of these indigenous berries for future functional product development must be accompanied by the blanching - as a pretreatment process, of the fully ripe fruits to attain enhanced vitamin C contents. Graphical