Analisis Kadar Vitamin B1 dalam Kacang Panjang (Vigna sinensis L.) Menggunakan Spektrofotometri Ultraviolet-Visible

Abstract

A Research of vitamin B₁ in long beans (Vigna sinensis L.) analyzed using ultraviolet-visible (uv-vis) spectrophotometry has been carried out at a wavelength of 435.6 nm. Vitamin B₁ reacted with bromthymol blue to form a yellow ion-associated complex in an ammonia-ammonium chloride as a buffer solution pH 7.6 which could be observed with a polyvinyl alcohol solubilizing agent. Long beans were boiled in water for 5, 10 and 15 minutes at 100^oC. Vitamin B₁ in long beans (Vigna sinensis L.) without boiling 0.0981 % ± 0.00021, boiling 5, 10 and 15 minutes were 0.0935 % ± 0.00015; 0.0834 % ± 0.00010 and 0.0743 % ± 0.00010 and the vitamin B₁ in the long bean boiled water at 5, 10 and 15 minutes boiling were 0.00102 % ± 0.000004; 0.00110 % and 0.00117 % ± 0.00001. It’s can be concluded that boiling long beans (Vigna sinensis L.) can cause a decrease in vitamin B₁ which decreases with increasing boiling time and vitamin B₁ in the cooking water increase due to the nature of vitamin B1 which is easily soluble in water