The Storage Effect against Vitamin C Content in crystal guava (Psidium guajava L.) Juice

Guava fruit (Psidium guajava L.) has many varieties, one of which is crystal guava. Crystal guava contains vitamin C which is easily oxidized by temperature. Therefore, this study aimed to determine the levels of vitamin C in crystal guava juice at different storage. Crystal guava samples were obtained from Bogor and then stored at different places and temperatures. Hence, guava fruits were placed in the freezer, refrigerator, and room temperature for 3 days, and all samples were juiced. Based on visual evaluation, guava fruit color is different. Moreover, the quantification method of vitamin C levels in guava juice by HPLC can be carried out with a flow rate of 1 mL/minute using the mobile phase ratio (methanol/water: 5/95, v/v), λmax: 265 nm and C18 as a stationary phase. Retention time of vitamin C in guava is around 2.765 minutes. The effect of storage of vitamin C content in guava juice from fresh samples, and guava stored in the freezer, in the refrigerator, and at room temperature are 3.28 mg/mL, 3.20 mg/mL, 1.65 mg/mL, and 0.82 mg/mL. Therefore, it can be concluded that the best storage of guava fruit is in the freezer because vitamin C levels in crystal guava do not have a significant difference after treatment.