Obtainment fruit juice from Inian fig (Opuntia ficus-indica) and evaluation of chemical and antioxidant properties

The fruit known as Indian fig (Opuntia ficus-indica) belongs to Cactaceae family. It grows in the Mediterranean region of Turkey. In recent years, significant studies about health benefits and nutritious value of this fruit have been conducted. The fruit is rich in terms of phenolic substances and antioxidants. Along with being consumed as fresh fruit in various countries such as Mexico, Chile and Spain, it is also consumed as marmalade, jam and fruit juice. Although the abundance of this fruit in the coastlines of Mediterranean region of our country, it is not considered as a commercial product. This study aimed to evaluate the consumption potential of this fruit as fruit juice. For this purpose, the changes in physical, chemical and antioxidant properties of fresh fruit juice from the storage fruits and -18°C stored fruit juice were determined during 4 weeks storage period. During the 4 week period phenolic contents percentages changed as follow; a 8.5% decrease in fresh fruit juice and a 4.13% decrease in -18°C stored fruit juice. Throughout the 4 week storage period, a decrease rate of 22.31% in fresh fruit juice and 41.44% in -18°C stored fruit juice was observed for the antioxidant activity (ABTS) of Indian fig juice. The antioxidant activities of fresh and -18°C stored fruit juices obtained from DPPH method were 87.87-87.09% and 84.46-75.57% respectively. The changes in color during storage period were also investigated. L value in fresh fruit juice changed between 28.16 and 21.33, while a and b values changed between 32.77-29.53 and 48.25-36.54 respectively. 19.32-11.16 for L value, 36.21-25.41 for a value and 33.30-20.36 for b value were detected for -18°C stored fruit juice. At the end of the 4 week storage period, pH, L, a, b, brix, dry matter, ash, antioxidant activity, total phenolic content, total bacteria count and total sugar content of fruit juices had a tendency of decrease; whereas, the titratable acidity showed an increase. The results of antimicrobial activity analysis showed that Indian fig fruit juice had no antimicrobial activity against the tested organisms; E. coli, S. aureus and Candida spp. Key words: Indian fig (Opuntia ficus-indica), fruit juice, antioxidant, phenolic content