Physicochemical properties, sensory acceptability, and antioxidant activity of chocolate bar fortified by solid lipid nanoparticles of gallic acid

Abstract

ABSTRACT The chocolate bar is a processed cocoa product that is rich in polyphenols, but polyphenols decrease during processing. Gallic acid encapsulated in the form of solid lipid nanoparticles (SLN) can be a solution for the fortification of phenolic compounds in chocolate bars. This study aimed to obtain the right concentration of SLN-gallic acid in the manufacture of chocolate bars. SLN was made by the double emulsion method and added fat rich in Monoacylglycerol (MAG) and Diacylglycerol (DAG) from coconut stearin as an emulsifier as well as a solid lipid matrix. The concentrations of SLN-gallic acid used for fortification were 0%, 2.5%, 5%, and 7.5%. The results showed that the addition of SLN-gallic acid affected the characteristics of physicochemical, sensorial, and antioxidant activity of chocolate bars. The higher the concentration of the addition of gallic acid SLN increased the total phenolic and antioxidant activity. However, the characteristics of color, texture, and organoleptic properties were decreased. The microstructure of the chocolate bar did not show a significant difference, namely the spherulite needlelike crystal. The best treatment was obtained by adding 5% of SLN-gallic acid on chocolate bars with an IC50 of 174.24 ± 2.48 and was favored by the panelists. The best treatment resulted in crystal morphology in the form of spherulite, small and spread out, and the polymorphism pattern was dominated by beta crystals. Thus, SLN-gallic acid was suitable for the fortification of up to 5% into chocolate bars.