The Effect of Adding the Leaves and Fruits of Morus alba to Rape Honey on Its Antioxidant Properties, Polyphenolic Profile, and Amylase Activity

Abstract

Two various species of mulberry (Morus sp.) were selected to enrich rape honey with dried leaves or lyophilized fruits (4% w/v). Finally, fruits and leaves of the ‘Ukraińska’ clone were introduced into the honey during creaming in concentrations from 1 to 4% w/v. The total phenolic content, antioxidant activity, anthocyanins content, and polyphenolic profile were tested in plant extracts and enriched honeys. Moreover, α-glucosidase, β-galactosidase, and diastase activities were investigated in honeys. For mulberry extracts, chlorogenic acid isomers and rutin were considered main antioxidant compounds. The antioxidant activity of honey enriched with mulberry leaves increased even more than 50 times, due to introducing numerous phenolic acids and flavonoid glycosides. A significant decrease in the diastase activity in honey depending on the content of added mulberry leaves (almost 50% decrease in the case of 4% addition) was found, suggesting the inhibitory effect of honey with mulberry leaves against carbohydrate hydrolyzing enzymes.