Characterization of Steam Volatiles in the Essential Oil of Black Currant Buds and the Antioxidant Properties of Different Bud Extracts

Abstract

Currently essential oil from black currant ( Ribes nigrum L.) buds is mainly used as a valuable perfumery ingredient. This study reports more comprehensive characterization of dormant buds of various black currant ( Ribes nigrum L.) cultivars which are grown in Northern European countries. Essential oils were isolated from the buds by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS), GC-flame ionization detection (GC-FID), and GC--olfactometry (GC-O). The most abundant compounds in black currant bud essential oil were sabinene, delta-3-carene, and terpinolene. The most frequent descriptors of the essential oil components assessed by GC-O were "woody", "terpene", "fruity", "sweet", "citrus", "herbaceous", "pine", "green", "oily", "herbal", and "musty". The residues obtained after hydrodistillation were separated into liquid and solid fractions. The solid fraction was dried and extracted with acetone (AE), while the liquid fraction (water extract) was divided in two parts, one of which was spray-dried (SDWF extracts) and the other freeze-dried (FDWF extract). In addition, a portion of whole frozen buds was extracted with methanol (ME). The radical scavenging capacity (RSC) of black currant bud extracts varied in a wide range; in the DPPH * reaction system FDWF at the applied concentration scavenged 43-79%; SDWF, 54-80%; AE, 16-36%; ME, 42-60% of radicals; while in the ABTS *+ reaction system the RSC was 39-72, 38-53, 1-5, and 30-49%, respectively. The total amount of phenolic compounds expressed in gallic acid equivalents in FDWF varied in the range of 132-192 mg/g; in SDWF, 140-209 mg/g; in AE, 49-107 mg/g; and in ME extracts, 111-180 mg/g.