Hydroxycitric acid, a compound with anti-obesity property, is commonly extracted from Garcinia cambogia. Batuan (Garcinia binucao), a close relative of Garcinia cambogia, is a Philippine indigenous fruit. Since these trees belong in the same genus, there is a high possibility that hyrdoxycitric acid is also present in batuan fruit. Hence, this study was conducted to isolate hydroxycitric acid from fresh batuan and determine the stability of this compound once the fruit is subjected to different processing conditions including steam blanching, drying, brine fermentation and freezing. Results revealed that Garcinia binucao is a potential source of hydroxycitric acid. The extracted acid from batuan ranges from 4.81 ± 0.12 to 4.83 ± 0.13 g/100 g sample. Water extraction method, compared to methanol and acetone extraction methods, is more effective in isolation of hydroxycitric acid from fresh batuan fruits. Steam blanching can reduce the hydroxycitric acid content of batuan by 13.66% up to 23.90% while drying can decrease the hydroxycitric acid content of the sample by 7.28% up to 17.39%. Brine fermentation for 20 days decreased the acid content of the sample by 39.54%. Lastly, freezing for 2 months reduced the acid content by 15.52% due to ice formation during freezing and drip loss during thawing. Based on the results of the study, the best conditions of batuan processing is drying at 60℃, steam blanching at 100℃ for 10 minutes, brine fermentation for maximum of 8 days and freezing up to 2 months. Among the studied processing methods, freezing was considered to be the most effective in preserving the hydroxycitric acid content of batuan fruits.