Solvent Free Microwave-Assisted Extraction of Antioxidants from Sea Buckthorn (Hippophae rhamnoides) Food By-Products

Abstract

After processing, every extraction process generates huge amount of unintended wastes, especially from fruits and vegetables which represent a major disposal problem for the food industry. They are promising sources of bioactive compounds that could be used for their favourable nutritional properties. Sea buckthorn juice production results in generation of large amount of by-products, which are suggested to contain substantial amounts of valuable natural antioxidants. Extracts obtained by solvent-free microwave hydrodiffusion and gravity (MHG) technique and conventional solvent extraction (CSE) method were analysed with HPLC for quantification of flavonoids along with evaluating their phenolic contents by Folin-Ciocalteu method and reducing power by the reduction of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. MHG is a green extraction method which offers important advantages like shorter extraction time (15 min), cleaner feature (no solvent or water used) and extraction of valuable flavonoids (Isorhamnetin, isorhamnetin 3-O-glucoside, isorhamnetin 3-O-rutinoside and quercetin 3-O-glucoside) at optimised power (400 W). Along with extracting similar flavonols in enough concentratioin, MHG extract has shown much higher phenolic contents (1,147 milligram gallic acid equivalents (GAE) per gram) against CSE extract (741 mg GAE/g) with greater antioxidant activity determined by DPPH assay.

Solvent-free extraction of food and natural products

“…analysis. MHG was also applied to sea-buckthorn by-products to extract specific antioxidants, producing a little lower yield of flavonol in a very short time (15 min) in comparison to classical methods but with a higher content of reducing compounds in MHG extracts [35]. Extracts obtained using the MHG technique and conventional solvent extraction (CSE) method were analyzed with HPLC for quantification of flavonoids along with evaluating their phenolic contents by Folin-Ciocalteu method and reducing power by the reduction of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical.…”

Bioactive compounds in sweet rowanberry fruits of interspecific Rowan crosses

“…As mentioned by many authors [1,46,47] this is a typical trait of the majority of fruit species not only in the case of antioxidant capacity of phenolics, ascorbic acid, but also where it concerns the relationship between phenolics and ascorbic acid and ROS [48,49].…”

Microwave-Assisted Extraction of Phenolic Antioxidants From Semiarid Plants

“…Moreover, with the increasing energy prices, the drive to reduce CO 2 emissions and eliminate the hazardous substances used in or generated by a method into the context of green chemistry, food industries are challenged to find or development new technologies in order to reduce energy consumption, product/process safety and control and for cost reduction and increased quality as well as functionality (Keith et al, 2007;Yan et al, 2010;Périno et al, 2011).…”

“…Therefore, exists an interest towards research on vegetable sources for identifying new antioxidants that could be used in the substitution of natural substances antioxidants instead of the synthetic ones (Chan et al, 2011;Périno et al, 2011;Li et al, 2012).…”