Ultrasound and microwave assisted extraction of bioactive compounds from sea-buckthorn pomace

Abstract

The aim of the study is to establish the optimal conditions for BAC extraction using ultrasound and microwave-assisted methods, as well as to analyze and to determine the optimal yield of BAC extracts obtained from powdered sea-buckthorn pomace.The powdered sea-buckthorn pomace used in our analysis was obtained by fine grinding with the PULVERISETTE 11 mill. For the extraction of lipo-soluble bioactive compounds, the following experimental parameters were established: the ratio of plant material to solvent, solvent concentration, extraction time, extraction technique, magnetron power, microwave pulse duration, as well as the power and frequency of ultrasound. Eight samples were analyzed at the same time, in duplicate, using different parameters and solvents. The qualitative and quantitative analysis of the bioactive compounds were performed using HPLC/PDA gradient method with C30-column for carotenoids. According to the HPLC data, the extracts obtained by UAE using ethyl alcohol and sunflower oil in a 1:1.5 ratio showed the highest yield of total carotenoids, with values of 73.02 ± 0.14 mg/100 g of extract. The lutein content ranged from 1.55 to 1.68 mg/100 g of extract, while the zeaxanthin content was between 3.99 and 4.32 mg/100 g of extract. The percentage of

DPPH radical scavenging varied between 0.34 ± 0.01% and 0.85 ± 0.01%, and the total phenolic content ranged from 0.41 ± 0.02 to 1.30 ± 0.05 mg of gallic acid equivalent (GAE)/g of extract. Results demonstrate that ultrasound extraction technologies for carotenoids from secondary

vegetal sources, sea-buckthorn pomace powder have considerable potential and could find

industrial applications in the food industry, where the demand for natural pigments is increasing.