Effects of the dose of administration, co-antioxidants, food matrix, and digestion-related factors on the in vitro bioaccessibility of rosmarinic acid - A model study.

This study aimed to determine the effect of the administration dose, combinations with co-antioxidants (vitamin C, caffeic acid, chlorogenic acid, catechin, rutin), and different food matrices (cooked and lyophilized hen eggs, chicken breast, soybean seeds, potatoes) on the potential bioaccessibility of rosmarinic acid (RA) in simulated digestion conditions, depending on the digestion stage (gastric and intestinal) and the contribution of physicochemical and biochemical digestion factors. The in vitro bioaccessibility of RA depended on the digestion stage and conditions. The physicochemical factors were mainly responsible for the bioaccessibility of RA applied alone. The higher RA doses improved its bioaccessibility, especially at the intestinal stage of digestion. Furthermore, the addition of vitamin C and protein-rich food matrices resulted in enhanced intestinal bioaccessibility of RA. In the future, the knowledge of factors influencing the bioaccessibility of RA can help enhance its favorable biological effects and therapeutic potential.

Bioaccessibility of Rosmarinic Acid and Basil (Ocimum basilicum L.) Co-Compounds in a Simulated Digestion Model-The Influence of the Endogenous Plant Matrix, Dose of Administration and Physicochemical and Biochemical Digestion Environment.

The objective of this study is to determine the effect of endogenous plant matrix components, dose and digestion-related factors on the bioaccessibility of rosmarinic acid and basil co-compounds in in vitro digestion conditions. Different forms of administration, i.e., basil raw plant material, dry extract, and isolated rosmarinic acid at various doses, were applied for the digestion experiment. To evaluate the contribution of biochemical and physicochemical digestion factors, samples were subjected to a full digestion process or treated only with a digestion fluid electrolyte composition without using biochemical components (i.e., digestion enzymes and bile salts), and bioaccessibility was monitored at the gastric and intestinal steps of digestion. The results showed that the components of the endogenous raw plant matrix significantly limited the bioaccessibility of rosmarinic acid and basil co-compounds, especially at the gastric stage of digestion. Physicochemical digestion factors were mainly responsible for the bioaccessibility of basil phytochemicals. Higher doses allowed maintenance of bioaccessibility at a relatively similar level, whereas the most negative changes in bioaccessibility were induced by the lowest doses. In conclusion, the determination of the bioaccessibility of bioactive phytochemicals from basil and factors influencing bioaccessibility may help in better prediction of the pro-health potential of this plant.

Phytochemical profile, in vitro bioaccessibility, and anticancer potential of golden root (Rhodiola rosea L.) extracts.

The effects of water and ethanolic (40 %, 70 %, and 96 %) extraction on the Rhodiola rosea L. phytochemical profile (HPLC analysis), stability during extract drying, potential bioaccessibility in simulated gastric and intestinal conditions, and cytotoxic activity against human colorectal adenocarcinoma cells (Caco-2 and HT-29 cell lines) were investigated. The phytochemical profile, extractability, and stability during extract processing depend on the solvent type. In general, compounds derived from dry extracts were characterized by higher bioaccessibility than those extracted from powdered plant material. In the case of salidroside, tyrosol, and rosavins, one of the highest bioaccessibilities (often about 100 %) were found for the 70 % ethanolic extract after gastric digestion. Furthermore, the 70 % ethanolic extract most effectively reduced the viability of Caco-2 cells (IC50 85.8 µg∙mL-1). The results suggest that golden root extracts, in particular 70 % ethanolic extract, seem to be promising supplements for the food industry.

Wheat rolls fortified with Greek oregano (Origanum vulgare ssp. hirtum (Link) Ietswaart) leaves - phytochemical changes during processing and simulated digestion, nutrient digestibility, and functional properties.

The effect of fortification of wheat rolls with 1-5% Greek oregano on the profile of phytochemicals, their changes during processing and simulated digestion (with special emphasis on rosmarinic acid), and in vitro protein and starch digestibility was assessed. Additionally, the main functional properties, e.g. the basic technological quality (baking loss, total volume, specific volume, density, porosity), rosmarinic acid distribution, and consumer acceptance of the fortified products were investigated. Rosmarinic acid content (HPLC analysis), total phenolic content, and in vitro antioxidant activities (ABTS, DPPH, FRAP) were determined. These parameters were analyzed during the preparation, processing, and simulated digestion (at the gastric and intestinal phase) of rolls. Potential bioaccessibility was calculated based on the digestion results. The fortification significantly improved rosmarinic acid content, total phenolic content, and antioxidant activity of the rolls. The potential bioaccessibility of phytochemicals was relatively good, especially at the intestinal phase. Nonetheless, higher doses of the supplement negatively affected the nutrient digestibility and the functional properties of the rolls. Regarding nutraceutical potential, fortified rolls seem to be a good food vehicle for Greek oregano phytochemicals, however, simultaneous optimization of nutritional and functional parameters seems to be challenging due to the multiple and often unpredictable factors affecting the final quality of fortified products.

Variation in Population and Solvents as Factors Determining the Chemical Composition and Antioxidant Potential of Arctostaphylos uva-ursi (L.) Spreng. Leaf Extracts.

The bearberry Arctostaphylos uva-ursi (L.) Spreng. has a long history of ethnopharmacological use. This species has been used in folk medicine for centuries as a rich source of raw material abundant in secondary metabolites and is important for medicinal and pharmacological purposes. The plant is a source of herbal material-Uvae ursi folium, which is highly valued and sought by pharmaceutical and cosmetic industries. The studied bearberry leaves can be classified as a suitable herbal material for use in pharmacy; therefore, the investigated populations can be a potentially valuable source of plant material for cultivation and can be used in in vitro cultures and in biotechnological processes. The objective of this study was to characterize the variability of the phytochemical composition and antioxidant activity of water and ethanol bearberry extracts from raw material collected from different natural populations. In each of the twelve A. uva-ursi sites, three leaf samples were collected and analyzed. The water extracts from bearberry leaves were characterized by similar concentration of arbutin (77.64-105.56 mg g-1) and a significantly higher concentration of hydroquinone (6.96-13.08 mg g-1) and corilagin (0.83-2.12 mg g-1) in comparison with the ethanol extracts -77.21-103.38 mg g-1, 10.55-16.72 mg g-1, 0.20-1.54 mg g-1, respectively. The concentration of other metabolites in the water extracts was significantly lower in comparison with the ethanol extracts. In the case of the water extracts, a significant effect of not only total phenolic compounds, but also hydroquinone on the antioxidant parameters, was observed, which indicates the solvent-related activity of these metabolites. Therefore, it is suggested that special attention should be paid to the concentration of not only arbutin, but also hydroquinone in Uvae ursi folium. The latter metabolite serving a very important function as an active bearberry ingredient should be controlled not only in alcoholic extracts but also in water extracts, since bearberry leaves are applied as infusions and decoctions. The results presented in this paper can contribute to appropriate selection of plant material for pharmaceutical, cosmetic, and food industries, with special emphasis on the antioxidant activity of different types of extracts.

In vitro bioaccessibility and activity of basil (Ocimum basilicum L.) phytochemicals as affected by cultivar and postharvest preservation method - Convection drying, freezing, and freeze-drying.

The effects of convection drying, freezing, and freeze-drying, on phytochemicals content, in vitro activity and bioaccessibility of sweet basil, cinnamon basil, red rubin basil, and lemon basil were investigated. For evaluation of bioaccessibility, rosmarinic acid content, phenolic content, and antioxidant potential of samples before and after gastric and intestinal steps of digestion were determined. Results showed that the content, activity and bioaccessibility of basil phytochemicals varied depending on the cultivar as well as the applied postharvest preservation. It was found that the frozen and freeze-dried plant materials were characterized by a higher phenolic level and antioxidant activity compared to the convection dried. However, in general, convection drying allows obtaining samples with higher bioaccessibility of phytochemicals compared to the low-temperature processed samples. These findings highlight the need for evaluation of basil cultivars and postharvest preservation methods regarding phytochemicals bioaccessibility, which might help in the classification in terms of pro-health quality.

Chemical Characteristics and Antioxidant Activity of Arctostaphylos uva-ursi L. Spreng. at the Southern Border of the Geographical Range of the Species in Europe.

The bearberry (Arctostaphylos uva-ursi L. Spreng.) is a source of herbal material-bearberry leaf (Uvae ursi folium), which is highly valued and sought by pharmaceutical and cosmetic industries. For many years, leaves of this plant have been used in traditional medicine as a diuretic, antimicrobial, and anti-inflammatory agent for various diseases of the urogenital tract. The bearberry has also been proposed as a natural antioxidant additive due to the high contents of phenolic compounds in its leaves. The study was focused on characterization of the basic phytochemical composition and antioxidant activity of extracts derived from bearberry leaves collected from plants located at the southern border of the geographical range of the species in Europe. The investigated herbal material is characterized by a different chemical profile compared to the chemical profiles of bearberry found in other parts of the continent. Bearberry extracts from plants growing in two different habitat types-heathlands and pine forests showed a wide range of variation, especially in the concentration of hyperoside, corilagin, and methylartutin and the total flavonoid contents. In addition to arbutin, bearberry can be a valuable source of phenolic compounds, which are mainly responsible for the antioxidant properties of extracts. The high content of phenols and high values of antioxidant parameters indicate a high potential of bearberry leaves to be used as a powerful natural source of antioxidants in herbal preparations. Therefore, the A. uva-ursi populations can be a source of plant material for pharmaceutical, cosmetic, and food industries.

Influence of Phenolic-Food Matrix Interactions on In Vitro Bioaccessibility of Selected Phenolic Compounds and Nutrients Digestibility in Fortified White Bean Paste.

This model study aimed to evaluate the effect of phenolic-food matrix interactions on the in vitro bioaccessibility and antioxidant activity of selected phenolic compounds (gallic acid, ferulic acid, chlorogenic acid, quercetin, apigenin, and catechin) as well as protein and starch digestibility in fortified white bean paste. The magnitude of food matrix effects on phenolics bioaccessibility and antioxidant activity was estimated based on "predicted values" and "combination indexes". Furthermore, the protein-phenolics interactions were investigated using electrophoretic and chromatographic techniques. The results demonstrated phenolic-food matrix interactions, in most cases, negatively affected the in vitro bioaccessibility and antioxidant activity of phenolic compounds as well as nutrient digestibility. The lowest in vitro bioaccessibility of phenolic compounds in fortified paste was found for quercetin (45.4%). The most negative impact on the total starch digestibility and relative digestibility of proteins was observed for catechin-digestibility lower by 14.8%, and 21.3% (compared with control), respectively. The observed phenolic-food matrix interactions were strictly dependent on the applied phenolic compound, which indicates the complex nature of interactions and individual affinity of phenolic compounds to food matrix components. In conclusion, phenolic-food matrix interactions are an important factor affecting the nutraceutical and nutritional potential of fortified products.

The effect of in vitro digestion, food matrix, and hydrothermal treatment on the potential bioaccessibility of selected phenolic compounds.

The effects of in vitro digestion, hydrothermal treatment, and food matrices (wheat flour, durum wheat flour, wholemeal wheat flour, corn flour, rice flour) on the bioaccessibility of phenolic compounds (gallic acid, p-coumaric acid, ferulic acid, chlorogenic acid, catechin) were investigated. The influence of experimental factors and their combinations was estimated based on the "Dose Correction Index" (DCI) concept. Generally, the applied conditions had a negative effect on the bioaccessibility of polyphenols; however, the effect depended on the type of compound and food matrix, which was reflected in different DCI values. A less unfavorable effect on the bioaccessibility was exerted by the rice flour (the lowest DCI values), but the most negative impact was found in the case of the wholemeal wheat flour. The DCI concept provides basic knowledge of the magnitude of factors affecting the bioaccessibility of polyphenols, which can be useful for designing fortified products with desirable bioactivity.

In vitro bioaccessibility and activity of Greek oregano (Origanum vulgare L. ssp. hirtum (link) Ietswaart) compounds as affected by nitrogen fertilization.

BACKGROUND: Greek oregano is a culinary and medicinal herb native to the Mediterranean region; however nowadays it is cultivated in many regions all over the world. It is commonly used as a spice for flavoring food products and in various traditional medicine applications. This study investigated the effect of nitrogen fertilization at 0-150 kg N ha-1 on the potential bioaccessibility and activity of Greek oregano compounds. For this purpose the total phenolic content, rosmarinic acid content, and antioxidant activities of the raw material, as well as digested fractions, were determined. RESULTS: Nitrogen fertilization had a negative influence on the phenolic content and antioxidant activity of raw material; however, its effect on the potential bioaccessibility varied depending on the dose. The highest potential bioaccessibility and activity was determined for plants fertilized with 30 kg N ha-1 . For the gastric and intestinal phases of digestion, the potential bioaccessibility percentages were 39.5% and 29.6% for total phenolics, 53.1% and 11.2% for rosmarinic acid content, 45.2% and 44.4% for antiradical activity against 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS), 39.2% and 27.2% for antiradical activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 50.2% and 23.4% for reducing power, respectively. CONCLUSION: The results showed that nitrogen fertilization is an important factor determining the in vitro bioaccessibility of Greek oregano compounds. Furthermore, the nutraceutical potential of herbs, in term of the bioaccessibility of bioactive compounds, may be optimized during plant cultivation by applying an accurate nitrogen level. © 2020 Society of Chemical Industry.

Protein⁻Phenolic Interactions as a Factor Affecting the Physicochemical Properties of White Bean Proteins.

This study was conducted with an aim to determine the interactions of pure phenolic compounds (gallic acid, ferulic acid, chlorogenic acid, quercetin, apigenin, and catechin) and phenolics from plant extracts (green tea and green coffee) with protein fractions of white bean (albumins and globulins). The physicochemical properties of complexes were established through an analysis of the UV-Vis spectrum; relative content of free amino groups, thiol groups, and tryptophan residues; chromatographic (SE-HPLC) and electrophoretic (SD-PAGE, Native-PAGE) properties; and conformational changes reflected by Fourier transform infrared spectra. Further, the effect of pH and ionic strength on the solubility and stability of complexes as well as the binding capacity of phenolics to proteins were determined. Results show that, in most cases, phenolics significantly affected the measured parameters; however, the effects were strongly differentiated by the type of phenolic compounds and protein fraction that were applied. Moreover, it may be that changes in the properties of complexes are reflected in the biological nature of proteins and phenolic compounds such as their bioavailability and physiological activity. However, due to the structural complexity of proteins, and the multitudinous factors that affect their interactions, such studies are a great and long-term challenge for the domain of food science.

Interactions of green coffee bean phenolics with wheat bread matrix in a model of simulated in vitro digestion.

Interactions of phenolics from green coffee bean flour (GCS) with the matrix of wheat bread have been studied employing direct (electrophoretic and chromatographic techniques) and indirect tests (nutrient digestibility). According to the chromatograms of digests, the antiradical activity of enriched bread was exhibited by free phenolics. An increase the area of chromatograms and some additional peaks observed for enriched bread may confirm some interactions of proteins with phenolics. The electrophoretic profile of these extracts showed that the band corresponding to a protein with molecular mass of 38 kDA had much higher intensity in enriched bread. Electrophoretic analysis of pellets remaining after digestion revealed GCS dose-dependent differences in bands corresponding to proteins with molecular masses of 52 kDa and 23 kDa. The relative digestibility of both starch and proteins was slightly decreased by addition of GCS; however, these changes did not exceed 10%, which justifies the use of this functional material.

Soymilk enriched with green coffee phenolics - Antioxidant and nutritional properties in the light of phenolics-food matrix interactions.

This study investigated the effect of soymilk fortification with green coffee extract (GCE) on phenolic contents, antioxidant capacity, relative in vitro digestibility of proteins and starch, and consumer acceptance. Special attention was paid to the effect of phenolics-food matrix interactions on fortification efficiency. Soymilk was enriched with GCE extracts containing 0.025-1mg of phenolics per 1mL-samples M1-M6. Compared to control, an increase in phenolic contents of up to 70% (M6) was observed for potentially bioaccessible fractions (AD). The antiradical activity and reducing power were also about 1.9 and 10.1 times higher, respectively. However, the determined phenolic and antioxidant activities differed from those predicted. Fortification improved the digestibility of nutrients when higher doses of GCE was introduced (M4-M6). The addition of GCE at an adequate dose allowed the production of a beverage with elevated hedonic properties. In conclusion, fortification was a successful in improving the pro-health status of soymilk.

Antioxidant, nutritional and functional characteristics of wheat bread enriched with ground flaxseed hulls.

Antioxidant capacity, nutritional and functional quality of wheat bread supplemented with 1-5% flaxseed hull (FH) were studied. Analyses of the chemically-extractable fraction show that supplementation with 5% of FH increased (compared to control) phenolics content (by 93%), radicals scavenging ability (by 176%) and reducing power (by 220%). Furthermore, phenolic antioxidants were bioaccessible in vitro (samples after simulated digestion). Fortification had no significant influence on rapidly and slowly digestible starch, in vitro starch digestibility and values of expected glycemic index; however, a decrease (up to 8%) of relative proteins digestibility was determined. Enrichment decreased loaf volume and increased crumb hardness. The results from sensory evaluation show that the incorporation of FH had a slightly unfavorable effect on bread sensory properties but ensured satisfactory consumer acceptability. In view of these facts, it is concluded that flaxseed hulls may be a beneficial food additive.

Effect of carob (Ceratonia siliqua L.) flour on the antioxidant potential, nutritional quality, and sensory characteristics of fortified durum wheat pasta.

This paper presents a study on the effect of carob flour addition from 1% to 5% (w/w) on phenolics content, antioxidant activity, nutritional quality, and sensory attributes of wheat pasta. An increase of about 2-folds, 18-folds and 3-folds in phenolics content, antiradical activity and reducing power for pasta fortified with 5% of carob flour was observed, respectively, compared to the control. Expected glycemic index (eGI) was increased proportionally to the substitution level and ranged between 72.2 and 83.9 for 1-5% of supplement, respectively. Furthermore, pasta fortification affected the in vitro bioaccessibility of nutrients. In case of 5% supplemented pasta, the digestibility of starch and protein decreased by about 9% compared to the control. The replacement of semolina with carob flour from 1% to 5% had no significant effect on pasta sensory attributes. In conclusion, carob flour seems to be a promising functional ingredient for pasta fortification.

Effect of fortification with parsley (Petroselinum crispum Mill.) leaves on the nutraceutical and nutritional quality of wheat pasta.

This study examines the nutraceutical (phenolics content, antioxidant activity, biological activity) and nutritional potential (starch and protein digestibility) of wheat pasta supplemented with 1-4% of powdered parsley leaves. Compared to the control, the potentially bioaccessible fraction of pasta fortified with 4% parsley leaves was characterized by 67% increased phenolics content, a 146% higher antiradical ability and 220% additional reducing power. Elevation of these parameters in fortified pasta was accompanied by an augmentation of its antiproliferative effect on carcinoma cells, which confirms their biological relevance. Supplementation of pasta had no significant effect on starch digestibility, while negatively affecting protein digestibility (a reduction by about 20% for pasta with a 4% supplement). Electrophoretic and chromatographic analyses indicated the presence of phenolic interactions with proteins and/or digestive enzymes. Fortification improved the nutraceutical and nutritional potential of the studied pasta; however, the final effect is made by many factors, including phenolics-food matrix interactions.

Changes of antioxidant potential of pasta fortified with parsley (Petroselinum Crispum mill.) leaves in the light of protein-phenolics interactions.

BACKGROUND: Pasta is considered as an effective carrier of prohealth ingredients in food fortification. The aim of this study was to examine the changes of antioxidant potential of wheat pasta affected by fortification with powdered parsley leaves. A special attention was paid to effectiveness of fortification in the light of proteinphenolic interactions. METHODS: To improve antioxidant activity of pasta, part of wheat flour was replaced with powdered parsley leaves from 1% to 4% (w/w). The total phenolics content was determined with Folin-Ciocalteau reagent. Antioxidant capacity was evaluated using in vitro assays - abilities to scavenge free radicals (ABTS) and to reduce iron (III) (FRAP). Predicted phenolic contents and antioxidant activity were calculated. To determine the protein-phenolics interactions SE-HPLC and SDS-PAGE techniques were used. RESULTS: Fortification of pasta had a positive effect on its phenolic contents and antioxidant properties. The highest phenolics level and antioxidant activity of pasta were obtained by supplementation with 4% of parsley leaves. However, in most cases experimental values were significantly lower than those predicted. The protein profiles obtained after SDS-PAGE differed significantly among control and enriched pasta. Furthermore, the addition of parsley leaves to pasta resulted in increase of peaks areas obtained by SE-HPLC. Results indicate the occurrence of the protein-phenolics interactions in fortified pasta. CONCLUSIONS: Overall, the effectiveness of fortification and consequently biological effect is limited by many factors including interactions between phenolics and pasta proteins. In the light of this results the study of potential interaction of bioactive supplements with food matrix should be taken into account during designing new functional food products.

Anticancer and antioxidant activity of bread enriched with broccoli sprouts.

This study is focused on antioxidant and anticancer capacity of bread enriched with broccoli sprouts (BS) in the light of their potential bioaccessibility and bioavailability. Generally, bread supplementation elevated antioxidant potential of product (both nonenzymatic and enzymatic antioxidant capacities); however, the increase was not correlated with the percent of BS. A replacement up to 2% of BS gives satisfactory overall consumers acceptability and desirable elevation of antioxidant potential. High activity was especially found for extracts obtained after simulated digestion, which allows assuming their protective effect for upper gastrointestinal tract; thus, the anticancer activity against human stomach cancer cells (AGS) was evaluated. A prominent cytostatic response paralleled by the inhibition of AGS motility in the presence of potentially mastication-extractable phytochemicals indicates that phenolic compounds of BS retain their biological activity in bread. Importantly, the efficient phenolics concentration was about 12 µM for buffer extract, 13 µM for extracts after digestion in vitro, and 7 µM for extract after absorption in vitro. Our data confirm chemopreventive potential of bread enriched with BS and indicate that BS comprise valuable food supplement for stomach cancer chemoprevention.

Bread enriched with quinoa leaves - the influence of protein-phenolics interactions on the nutritional and antioxidant quality.

This paper investigates the functional and potential biological properties of bread fortified with quinoa leaves (QL) in the light of protein-phenolic interactions. The addition of QL changed the textural properties of bread crumb. With the replacement of wheat flour by QL (1-5%), a linear increase in crumb hardness, cohesiveness and gumminess was observed. Fortification positively affected antioxidant properties and phenolic contents; however, in some cases experimental values were significantly lower than those predicted. The QL addition affected nutrient content and digestibility. The starch digestibility of the bread investigated in this study was inversely proportional to the percentage content of QL (the changes in protein digestibility were not so pronounced). Increasing peak areas of extracts obtained after digestion of fortified bread and the significant reduction of free amino groups confirm the presence of interactions between phenolics and proteins. The quality of fortified bread is strongly affected by phenolic compounds and food matrix interactions.

Elicitation and precursor feeding as tools for the improvement of the phenolic content and antioxidant activity of lentil sprouts.

This study considered the efficacy of UV-B treatment and precursor feeding with phenolic synthesis precursors in relation to the production of polyphenol-rich sprouts. The used modifications of sprouting caused an increase in the activities of tyrosine ammonia-lyase and phenylalanine ammonia-lyase. The biotechnological approaches used allowed for a significant enhancement of the antioxidant potential of sprouts that was strongly and positively correlated with total phenolic content. The highest increase of flavonoids content was found for the sprouts obtained with phenylalanine treatment (2.41mg/gFM, 1.6-fold with respect to the control). The highest increase in the antioxidant capacity was found for the sprouts obtained with phenylalanine (an increase of 27% after solid-liquid extraction) and combined UV-tyrosine treatments (an increase of 44% for potentially bioaccessible fractions). The results of this work may suggest the use of elicitation supported by precursor feeding as an easy and cheap tool for improving the nutraceutical potential of low-processed food.