Effect of Ultrasonication on Some Chemical Properties of Red Ginger (Zingiber officinale var. rubrum) Oleoresin Nanoemulsion Bioactive Compounds

Abstract

Nanotechnology has developed in various industrial fields. This encourages innovation in the use of additives such as antioxidants, dyes, flavors, and other active ingredients that can be modified in the form of nanoemulsions. Red ginger contains oleoresin, which has thick properties to form a paste. These properties make oleoresin difficult to mix with food, disperse, hydrophobic and susceptible to the effects of heat and light. One solution to overcome this problem is to convert oleoresin into a nanoemulsion so that it has high solubility, is stable, good bioavailability, and improves sensory properties. One technique for making nanoemulsions is ultrasonication. The high-intensity ultrasonication effect can cause the movement of the oil phase into the liquid phase in the form of droplets, thereby increasing the pressure in the liquid and resulting in the breakdown of the oil droplets into smaller sizes. The purpose of this research was to determine the effect of ultrasonication on some chemical properties of the red ginger oleoresin nanoemulsion bioactive compounds, which includes antioxidant activity, total phenol, gingerol content, and droplet microstructure. The study used a completely randomized design with four treatments based on sonication time. Data from the test results were analyzed using analysis of variance (ANOVA) and Tukey's advanced test. Based on the results of the analysis, it was found that ultrasonication had effect on the red ginger oleoresin nanoemulsion biactive compounds. The best treatment is 90 min of sonication. The antioxidant activity (IC50) was 11.45±3.48 ppm, the total phenolic content was 3342.74±283.00 mg GAE/g, and the gingerol content was 0.33 %. The nanoemulsion droplet microstructure complies with the standard; that is, the particles are in the form of small spheres, like balls, and there are no visible holes or cracks on the surface of the particles. HIGHLIGHTS Red ginger contains higher oleoresin than other types of ginger Oleoresin is in the form of a viscous paste, so it is hydrophobic Application of nanoemulsion to oleoresin can increase solubility and bioavailability One of the methods for making nanoemulsions is using ultrasonication The novelty in this research is the manufacture of red ginger oleoresin nanoemulsion using the ultrasonication method to increase the content of bioactive compounds such as antioxidant activity, total phenolic content, and gingerol GRAPHICAL ABSTRACT