Investigation on High-Value Bioactive Compounds and Antioxidant Properties of Blackberries and Their Fractions Obtained by Home-Scale Juice Processing

Abstract

Blackberry pomace represents a valuable but underused byproduct of juice manufacturing. Its further applicability in various food systems is facilitated by detailed knowledge of its own bioactive potential. This study was focused on the investigation of the polyphenolic compound profile, total phenolic and ascorbic acid content, as well as 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity of blackberries (Rubus fruticosus L.) coming from spontaneous flora of two different areas of Romania, Paltinis (Sibiu County) and Zugau (Arad County) and their fractions, juice and pomace, resulting from home-scale processing. To ensure a satisfactory shelf life, the blackberry pomace was subjected to convective drying (60 °C for 12 hours) and the impact of this treatment on the antioxidant properties was evaluated. No significant differences in the investigated characteristics according to the place of origin were recorded. However, a slight increase in the antioxidant properties of fruits and fractions from the Zugau region, characterized by higher temperatures and a lower precipitation regime, was noticed compared with samples derived from the Paltinis area. The drying of blackberry byproducts led to losses of 10–23% in the content of the investigated bioactive compounds and DPPH radical scavenging activity. A significant correlation between DPPH radical scavenging activity and the total phenolic content has been recorded. Our findings are of interest in blackberry selection to enhance the level of bioactive compounds in the targeted products. The obtained results confirm that the blackberry processing byproducts may be regarded as a promising source of high-quality bioactive compounds and a proven radical scavenging capacity, representing a starting point for further analyses. This study responds to a global issue regarding fruit byproduct management in order to ensure the sustainable development of a circular economy.

Strategies to Improve the Thermo-Oxidative Stability of Sunflower Oil by Exploiting the Antioxidant Potential of Blueberries Processing Byproducts

“…As it has been displayed in other studies, the origin area, along with other factors such as fruit variety, ripeness stage, harvest period, plant nutrition, and storage conditions, influence the development of bioactive substances in blueberries and their fractions [17,19] PV of sunflower oil samples subjected to thermal treatment at 180 • C was evaluated in order to reveal the development degree of primary lipid oxidation in response to high-temperature exposure. Hydroperoxides are odorless and colorless compounds generated by primary lipid oxidation.…”

“…A low moisture content for both ABBE (3.29%) as well as PBBE (3.71%) has been registered. The low values of moisture content make microbial and enzymatic degradation impossible, thus ensuring an increased shelf life for natural extracts obtained by freeze-drying [19].…”

“…The conditioning of byproducts obtained by juice centrifugal extraction from frozen blueberries, in laboratory conditions using a juice extractor (MES3500, 700 W, Bosch GmbH, Stuttgart, Germany) following a simple procedure, usually applied at household level, were performed according to Metzner Ungureanu et al [19]. Thus, the blueberry byproducts were conditioned by a convective drying at 60 • C for 12 h in an electric oven (Esmach SpA-Ali Group/Italy, 1200 W, 50 Hz) then grinded using a laboratory mill (Grindomix Retsch GM200, Haan, Germany).…”

“…The antioxidant activity of the extracts obtained from fruit processing byproducts has been previously proved by different complex methods such as 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay, ferric reducing antioxidant power (FRAP) assay, cupric reducing antioxidant capacity (CURPAC) assay, Trolox-equivalent antioxidant capacity (TEAC) assay, total radical trapping antioxidant parameter (TRAP) assay, oxygen radical absorbance capacity (ORAC) assay, 2,2 -azinobis-(-3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging assay and lipid peroxidation inhibition capacity (LPIC) assay [16][17][18][19][20]. Depending on the mode of action of the antioxidant compounds, these methods evaluate the capacity of antioxidants to quench the free radicals or the ability of antioxidants to reduce the oxidants [16].…”

“…Depending on the mode of action of the antioxidant compounds, these methods evaluate the capacity of antioxidants to quench the free radicals or the ability of antioxidants to reduce the oxidants [16]. Regarding the total phenolic compounds investigation, Folin-Ciocalteu spectrophotometric assay is the most common method used to quantify the total phenolic content and high-performance liquid chromatography (HPLC) is often used in profiling the individual polyphenolic compounds [16][17][18][19][20].…”