Determination of potential level of Indonesian rhizomes as an antioxidant based on phenolic compound and antioxidant activity

Abstract This study was aimed to determined of the potential level of rhizomes from Indonesia as an antioxidant. The calculated of potential level rhizome based on the total phenolic compound and antioxidant activity.The phenolic compound was determined using the Folin-Ciocalteau method, antioxidant activity was determined by the DPPH (1-diphenyl-2-picrylhydrazyl) method expressed in IC50. Potential level was calculated by comparing the value of total phenolic compound and antioxidant activity. The results showed that red ginger ( Zingiber officinale var Rubrum) had the highest a phenolic and flavonoid content. Therefore that red ginger, Zingiber officinale var Rubrum is the most potential level as an antioxidant followed by Curcuma longa, Curcuma zedoaria, Curcuma zanthorrhiza, and Curcuma aeruginosa Roxb.</jats:p

Effect of α-Amylase and Glucoamylase Enzymes on Chemical Qualities of Vinegar from Banana Peel

Abstract The rate of banana consumption in Indonesia is reported to be increased. Abundant banana peels causes environmental problem. Peels of banana still have the potential to be utilized in the making of vinegar. Banana peels have high contents of fiber and carbohydrate, however breakage of polysaccharide bonds with enzyme is necessary. The α-amylase and glucoamylase are suitable enzymes to optimally break the polysaccharide bonds. The objective of this research was to determine the effect of α-amylase and glucoamylase on chemical qualities of banana-peel vinegar. The experimental design used was a Block Randomized Design with two factors and three replications. The ‘A’ factor was concentration of α-amylase at three levels (0.05%; 0.1%; 0.15%). The ‘B’ factor was concentration of glucoamylase at two levels (0.1%; 0.15%). Observation parameters included reducing-sugar, concentration of alcohol and acetic acid, and pH values. The high level of acetic acid was obtained from A2B1 (0.10% α-amylase; 0.10% glucoamylase) with an average value of 4.05% and pH of 3.52 on day-30 of fermentation period. An average value of reducing-sugar level on day-1 was 0.55% (g/ml) accompanied by alcohol content reduction of 0.386%. The best quality of banana-peel vinegar was resulted from the A2B1 treatment (0.10% α-amylase, 0.10% glucoamylase). Good quality vinegar was characterized by its aqueous liquid form, acetic acid odor with level at least 4%, residual alcohol at maximum level of 10%. The study has implications for the utilization of banana peel waste as natural preservatives.</jats:p