Penentuan Kadar Vitamin C dari Produk Sirup Markisa secara Spektrofotometri Visibel dan Uji Aktivitas Antioksidan dengan Metode DPPH

Abstract

Background: Passion fruit contained a lot of vitamin C and was widely processed into passion fruit syrup. In making passion fruit syrup, there was a heating process so that vitamin C, which is sensitive to heat, decreased in amount after being processed into syrup. In this case, it was necessary to determine the vitamin C content and antioxidant activity of passion fruit syrup products. Objective: This study aimed to determine the vitamin C content and antioxidant activity of each passion fruit syrup product. Method: The method used to determine vitamin C content was visible spectrophotometry at a wavelength of 578.7 nm with the addition of ammonium molybdate; validation of the method included linearity, LOD, LOQ, accuracy, and precision. Antioxidant activity was tested using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging method. Results: The results showed that the average levels of vitamin C of passion fruit syrup products in samples A; B; C; and D were 6.6887 ± 0.0790 mg/100 g; 7.9807 ± 0.0572 mg/100 g; 9.7131 ± 0.0753 mg/100 g; and 8.6861 ± 0.0753 mg/100 g, respectively. The results of the method validation test showed that the value of r was 0.9976 obtained; the average value of % recovery of samples A; B; C; and D was 95.37%; 94.74%; 95.63%; 95.34% respectively, the relative standard deviation (RSD) of samples A; B; C; and D was 0.97%; 1.00%; 0.93%; 0.93%, respectively. The antioxidant activity of passion fruit syrup products against DPPH free radicals was expressed by IC50. The average IC50 values of samples A; B; C; and D were 1958.1619 µg/mL; 1754.9415 µg/mL; 1579.4696 µg/mL; and 1586.8530 µg/mL, respectively. Conclusion: The results concluded that each passion fruit syrup product had vitamin C content with a certain value and had met the requirements of method validation. All passion fruit syrup products fell into the category of very weak antioxidant activity.