Abstract The effect of ohmic heating on bioactive compounds in bignay (Antidesma bunius) fruit juice during ohmic heating were evaluated. The parameters measured were total phenol, anthocyanin, flavonoid, and antioxidant activity. Ohmic heating was conducted at 70, 90, and 110 °C, and samples were collected at heating times of 0, 15, 30, and 45 minutes. Electrical conductivity of bignay fruit juice increased linearly with temperature with values ranged from 0.012 S/m at 32 °C to 0.039 S/m at 110 °C. Insignificant change in total phenol was observed, while anthocyanin and flavonoid showed significant degradation and the degradation kinetics followed the first-order kinetic model. The degradation rate constants for anthocyanin ranged from 0.0016 to 0.0213 min-1 with activation energy (Ea) of 63.880 kJ/mol and the degradation rate constants for flavonoid were in the range of 0.0107 to 0.0209 min-1 with activation energy of 18.210 kJ/mol. Antioxidant activities (IC50) obtained from DPPH method ranged from 0.106-0.168 mg/mL while those obtained from ABTS method ranged from 0.131-0.161 mg/mL. The results indicate that anthocyanin and total phenol in bignay fruit juice is much more stable during heating compared to flavonoid.

Abstract Bignay fruits are produced from wild trees of Antidesma bunius Spreng which can be found in India, Ceylon, and South East Asia countries. Each mature tree can produce hundreds of kilograms of fruits per year, so this fruit has the potential to be used as a raw material in juice and beverage industries. In addition, recent trends in consumer demand indicates that consumers are more inclined to demand products which can provide health benefits. In order to assess the potential of bignay fruit as a raw material for juice production, it is important to determine the health-promoting bioactive compounds contained in fresh bignay fruit juice. Therefore, the objective of this study was to determine the concentration of bioactive compounds in fresh bignay fruit juice. Results obtained from this study showed that bignay fruit juice contained 1202.5 mg GAE/100 mL of total phenolic, 436.602 mg/100 mL of anthocyanin, 48.931 mg/100 mL of ascorbic acid, and 3.78 mg/100 mL of flavonoid. The scavenging activities obtained from DPPH and ABTS methods were 0.110 mg/mL and 0.126 mg/mL respectively. The above results indicate that bignay fruits contain health-promoting chemical compounds and can be used as a natural source of antioxidants.