Oregano is native to the Mediterranean region and it has been reported to contain several phenolic compounds particularly flavonoids that have been related with multiple bioactivities towards certain diseases. Oregano is cultivated in the island of Lemnos where the climate promotes its growth and thus it could be further used in promoting local economy. The aim of the present study was to establish a methodology for the extraction of total phenolic content along with the antioxidant capacity of oregano by using response surface methodology. A Box–Behnken design was applied to optimize the extraction conditions with regard to the extraction time, temperature, and solvent mixture with the use of ultrasound-assisted extraction. For the optimized extracts, identification of the most abundant flavonoids (luteolin, kaempferol, and apigenin) was performed with an analytical HPLC-PDA and UPLC-Q-TOF MS methodology. The predicted optimal conditions of the statistical model were identified, and the predicted values confirmed. The linear factors evaluated, temperature, time, and ethanol concentration, all showed significant effect (p < 0.05), and the regression coefficient (R2) presented a good correlation between predicted and experimental data. Actual values under optimum conditions were 362.1 ± 1.8 and 108.6 ± 0.9 mg/g dry oregano with regard to total phenolic content and antioxidant activity based on 2,2-Diphenyl-1-picrylhydrazyl (DPPH) assay, respectively. Additionally, further antioxidant activities by 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) (115.2 ± 1.2 mg/g dry oregano), Ferric Reducing Antioxidant Power (FRAP) (13.7 ± 0.8 mg/g dry oregano), and Cupric Reducing Antioxidant Capacity (CUPRAC) (1.2 ± 0.2 mg/g dry oregano) assays were performed for the optimized extract. The extract acquired under the optimum conditions contain an adequate quantity of phenolic compounds that could be used in the production of functional foods by food enrichment procedure.
Petroselinum crispum is native to the Mediterranean region and has been reported to contain several phenolic compounds in addition to the highest quantity of apigenin among several natural raw materials. The aim of the present study was to establish an extraction method for the most abundant phenolic compounds of Petroselinum crispum leaves by using response surface methodology. A Box–Behnken design was applied to optimize the extraction conditions with regards to the extraction time, temperature, solvent mixture, and sample to solvent ratio with the use of ultrasound-assisted extraction. An analytical HPLC-PDA methodology was developed to accurately quantify the phenolic compounds in the extracts. Identification of the most abundant phenolic compounds (luteolin, caffeic acid, and apigenin) was also performed with an UPLC-Q-TOF MS methodology. The predicted optimal conditions of the statistical model were identified, and the predicted values confirmed. Actual values of 23.92 ± 1.86 with 100 mL/g, 40% ethanol, 70 °C and 40 min, 19.10 ± 0.75 with 20 mL/g, 0% ethanol, 70 °C and 40 min, and 25.29 ± 1.82 μg/g dry parsley with and 100 mL/g, 0% ethanol, 25 °C and 40 min of luteolin, caffeic acid, and apigenin respectively, were estimated. Total phenolic content and antioxidant activities by DPPH, ABTS, FRAP, and CUPRAC assays were performed for the extracts. The extracts acquired under the optimum conditions contain an adequate quantity of phenolic compounds that could be used in the production of functional foods by food enrichment prcedure.
Consumer interest in health-promoting foods has prompted researchers to use wine by-products to increase food’s functional characteristics. This research aims to examine the skin bioactivities of Samos white (small-berry Muscat) and red (Augustiatis) grape skin extracts (M-GSkE, A-GSkE). Total phenolic content, antiradical activity, the inhibition of plasma oxidation and platelet aggregation, and the phenolic profile were examined. A-GSkE and M-GSkE showed high total phenolics (1.19 ± 0.13 vs. 2.12 ± 0.23 mM GAE), antiradical activity (7.7 ± 0.4 vs. 6.6 ± 0.3 μM GAE for ABTS; 31.12 ± 0.8 vs. 26.4 ± 1.0 μM GAE for DPPH), resistance to plasma oxidation (5.7 ± 0.4 vs. 1.1 ± 0.2 μM GAE), and antithrombotic activity (19.7 ± 0.1 vs. 26.6 ± 0.2 μM GAE). Ferulic (41.3 ± 0.1 > 13.2 ± 0.1 μg/g DM), vanillic (26.3 ± 1.7 > 12.2 ± 1.2 μg/g DM), and gallic (16.6 ± 0.1 > 8.4 ± 2.9 μg/g DM) acids along with ε-viniferin (3.6 ± 0.4 > 2.8 ± 0.3 μg/g DM) were identified in higher content in A-GSkE. Catechin (59.8 ± 1.5 μg/g DM), chlorogenic acid (43.8 ± 0.9 μg/g DM), and resveratrol (0.83 ± 0.13 μg/g DM) were identified only in M-GSkE, while caffeic acid 19.8 ± 0.4 μg/g DM) and daidzein (16.8 ± 0.1 μg/g DM) were identified only in A-GSkE. The specialized bioactivities researched in two previously unexplored Samos’ wine grape skin extracts give them added value. The valorization of such by-products promises a sustainable future in the food sector of local communities and an improvement in local public health.
Antioxidants are known to play a crucial role in maintaining cellular health by neutralizing harmful free radicals. Among various dietary sources of antioxidants, wheat-based products, particularly flours, have gained significant attention due to their potential health benefits. Durum wheat, a widely cultivated species, serves as a primary ingredient in numerous food products. However, limited research has been conducted to assess the antioxidant activity of flours obtained from durum wheat varieties. In this study, we aimed to comparatively evaluate the antioxidant and antiplatelet potential of flours from 22 selected durum wheat varieties cultivated in Greece. We focused on three major parameters for antioxidant activity measurement: total phenolic content, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and ferric-reducing antioxidant power (FRAP). The total phenolic content was determined using the Folin–Ciocalteu method, while DPPH and FRAP assays were employed to assess the ability of flours to scavenge free radicals and reduce ferric ions, respectively. The antiplatelet activity was evaluated using a platelet-activating factor inhibition assay (PAF) in platelet-rich plasma. Analysis of the data revealed notable differences in the total phenolics and antioxidant and antiplatelet activities among the tested samples. The total phenolic content ranged from 624.0 ± 3.5 to 950.0 ± 5.3 μg of gallic acid equivalent/g flour with the variety Zeta E having the highest content. The antioxidant activities based on the DPPH and FRAP assays ranged from 0.56 ± 0.02 to 2.26 ± 0.08 and 1.93 ± 0.02 to 3.65 ± 0.03 μmol of Trolox equivalent/g flour, respectively, with the varieties Marco Aurelio and Zeta E exerting the highest antioxidant activities in the DPPH and FRAP tests, respectively. In addition, the IC50 values for the antiplatelet activity ranged from 0.72 ± 0.21 to 3.06 ± 0.17 in mg of flour, with the variety of Zoi exhibiting the highest antiplatelet activity. Overall, this comparative evaluation highlights the differences in the antioxidant and antiplatelet activities among flours obtained from 22 different durum wheat varieties cultivated in Greece. The results from this study aid in the selection of wheat varieties with superior antioxidant and antiplatelet capacities for use in bakery food formulation and dietary recommendations.
In recent years, the health-promoting properties of plant-derived compounds have garnered increasing scientific interest. Notably, tomatoes and pumpkins (Cucurbita moschata), renowned for their abundant phytochemicals and associated biological activities, have become focal points of research. This study investigated the extraction of phenolic compounds from tomatoes and pumpkins cultivated on Lemnos, an Aegean Island, aiming to enhance the nutritional profiles of food products. We established an extraction protocol for total phenolics and evaluated the antioxidant capacity using response surface methodology. Utilizing a central composite design, we optimized the extraction parameters, with time and ethanol concentration identified as critical factors (p < 0.05). The optimized extracts demonstrated substantial phenolic content (9.47 ± 0.08 and 4.52 ± 0.05 mg GAE/g for tomatoes and pumpkins, respectively) and antioxidant capabilities as determined by DPPH (7.65 ± 0.08 and 5.78 ± 0.05 μmol TE/g, respectively), ABTS (9.27 ± 0.02 and 3.95 ± 0.04 μmol TE/g, respectively), FRAP (5.25 ± 0.09 and 2.99 ± 0.03 μmol TE/g, respectively), and CUPRAC assays (2.3 ± 0.04 and 1.25 ± 0.03 μmol TE/g, respectively). Following extraction, the phenolic compounds were encapsulated using maltodextrin and subsequently freeze-dried, yielding high encapsulation efficiency. In alignment with a comprehensive strategy aimed at fostering functional snacks that enhance local economic and public health outcomes, vegetables sourced from local farms were employed to develop a savory cereal bar enriched with tomato extract and a sweet cookie infused with pumpkin extract.
Cistus creticus L. is a Mediterranean plant rich in phenolic constituents with substantial antioxidant potential. This study developed an integrated experimental approach com-bining ultrasound-assisted extraction (UAE), phenolic profiling, maltodextrin-based mi-croencapsulation, incorporation into a bakery matrix, simulated gastrointestinal digestion, and passive membrane permeation. UAE was optimized using a three-factor Box–Behnken response surface design considering temperature, actual sonication time, and ethanol concentration. The predicted optimum was obtained at 80 °C, 40 min, and 60% (v/v) etha-nol. Experimental verification yielded a total phenolic content of 354.1 ± 0.9 mg GAE/g dry plant material and DPPH antioxidant capacity of 115.6 ± 0.7 mg TE/g dry plant material, closely matching model predictions. UHPLC–QTOF-MS/MS enabled the tentative assign-ment of 19 phenolic compounds, quantified using analyte-specific calibration curves normalized to syringaldehyde as an internal standard. Freeze-drying with maltodextrin at a 1:30 core-to-wall ratio (w/w) resulted in 88.4 ± 0.9% phenolic recovery and 99.4% en-capsulation efficiency. The encapsulated extract showed greater retention of Folin-reactive constituents during storage than the non-encapsulated extract. During modified static INFOGEST digestion, measurable Folin-reactive equivalents increased progressively, with the extent of change depending on formulation and food-matrix incorporation. Passive membrane transport was subsequently assessed using PermeaPad® with donor prepara-tions standardized to an initial total load of 20 mg GAE. After 240 min, cumulative perme-ated fractions were 16.5% for the non-encapsulated extract, 26.0% for the encapsulated ex-tract, 18.5% for grissini containing non-encapsulated extract, and 32.0% for grissini con-taining encapsulated extract. Overall, microencapsulation and incorporation into a bakery matrix modified the stability, gastrointestinal behavior, and passive membrane transport of the C. creticus Folin-reactive fraction demonstrating technological feasibility.