Byproducts (Flour, Meals, and Groats) from the Vegetable Oil Industry as a Potential Source of Antioxidants

Abstract

The present study presents the use of photochemiluminescence assay (PCL) and 2,2 diphenyl-1-picryl-hydrazyl (DPPH), 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), the ferric reducing antioxidant power (FRAP), and cupric ion reducing antioxidant capacity (CUPRAC) methods for the measurement of lipid-soluble antioxidant capacity (ACL) of 14 different byproducts obtained from the vegetable oil industry (flour, meals, and groats). The research showed that the analyzed samples contain significant amounts of phenolic compounds between 1.54 and 74.85 mg gallic acid per gram of byproduct. Grape seed flour extract had the highest content of total phenolic compounds, 74.85 mg GAE/g, while the lowest level was obtained for the sunflower groats, 1.54 mg GAE/g. DPPH values varied between 7.58 and 7182.53 mg Trolox/g of byproduct, and the highest antioxidant capacity corresponded to the grape seed flour (7182.53 mg Trolox/g), followed by walnut flour (1257.49 mg Trolox/g) and rapeseed meals (647.29 mg Trolox/g). Values of ABTS assay of analyzed samples were between 0 and 3500.52 mg Trolox/g of byproduct. Grape seed flour had the highest value of ABTS (3500.52 mg Trolox/g), followed by walnut flower (1423.98) and sea buckthorn flour (419.46). The highest values for FRAP method were represented by grape seed flour (4716.75 mg Trolox/g), followed by sunflower meals (1350.86 mg Trolox/g) and rapeseed flour (1034.92 mg Trolox/g). For CUPRAC assay, grape seed flour (5936.76 mg Trolox/g) and walnut flour (1202.75 mg Trolox/g) showed the highest antioxidant activity. To assess which method of determining antioxidant activity is most appropriate for the byproducts analyzed, relative antioxidant capacity index (RACI) was calculated. Depending on the RACI value of the analyzed byproducts, the rank of antioxidant capacity ranged from −209.46 (walnut flour) to 184.20 (grape seed flour). The most sensitive methods in developing RACI were FRAP (r = 0.5795) and DPPH (r = 0.5766), followed by CUPRAC (r = 0.5578) and ABTS (r = 0.4449), respectively. Strong positive correlations between the antioxidant capacity of lipid-soluble compounds measured by PCL and other methods used for determining antioxidant activity were found (r > 0.9). Analyses have shown that the different types of byproducts obtained from the vegetable oil industry have a high antioxidant activity rich in phenolic compounds, and thus their use in bakery products can improve their nutritional quality.

Rosehip (Rosa canina L.) Meal as a Natural Antioxidant on Lipid and Protein Quality and Shelf-Life of Polyunsaturated Fatty Acids Enriched Eggs

“…The highest concentration of TPC was observed in the RF2 eggs (46.79 μg GAE/g) compared to RF0 (40.93 μg GAE/g). Although to our knowledge there are no studies in which rosehip meal was used as a natural antioxidant for PUFA-enriched eggs, our results are comparable with studies that used different natural sources like rosemary [ 48 , 49 ], seabuckthorn, and grapeseed meal [ 6 , 50 ]. Studies in which flaxseed meals combined with synthetic antioxidants like vitamin E, butylated hydroxyanisole (BHA), and butylated hydroxytoluene (BHT) ([ 51 , 52 ] are available, however, the consumers’ concern regarding their safety has motivated the food industry to seek natural alternatives [ 53 , 54 , 55 ].…”

Proximate Composition, Physicochemical, and Lipids Profiling and Elemental Profiling of Rapeseed (Brassica napus L.) and Sunflower (Helianthus annuus L.) Grown in Morocco

“…e DPPH activity of the tested samples was 17.29 ± 1.23 mg AAE/g DM (rapeseed) and 4.61 ± 0.76 mg AAE/g DM (sunflower) (Table 2). Numerous studies have demonstrated that the antioxidant activity of seeds is strongly affected by the content of phenolic compounds, including TPC and TFC, and this relationship has been reported by other authors [58].…”

Research on the Potential Use of Grape Seed Flour in the Bakery Industry

“…Multescu et al [ 41 ] studied the phenolic content, the flavonoid content, and the lipid-soluble antioxidant capacity of 14 by-products (rapeseed meals, grape seed flour, sunflower meals, seabuckthorn flour, etc.) obtained in the vegetable oil industry.…”