Sample Preparation
Depending on the type of fruits, 10 to 30 g of the edible portions were either blended for
approximately one minute to a paste, or crushed and homogenized using a pestle and mortar.
Guava, star fruit and water apple were homogenized without peeling the skin while the other
four fruits were crushed after the skin was removed. The homogenized sample was
transferred into a 100-mL volumetric flask and 50% ethanol was added up to the mark. The
mixture was shaken manually or with a vibrator for 10–15 min and filtered under suction. In
situations where the filtrate appeared to be very cloudy, the filtrate was centrifuged to obtain
a clear supernatant liquid, which was subsequently used for the various analyses. All tests
were performed in triplicates within a week and the extracts were stored at –20oC until used.
To study the effect of storage on total phenol content (TPC) and ascorbic acid content
(AAC), the freshly cut fruit was sealed in a plastic bag and stored at 4
oC for 4–5 days after
which it was treated with 50% ethanol in the same way as before.