Dariusz Dziki

Antioxidant and anticancer activities of Chenopodium quinoa leaves extracts – In vitro study

The nutraceutical potential of Chenopodium quinoa Leaves (ChL) was assessed through analyses of their phenolic content, elucidation of the effect of ChL phenolic compounds on cancer cell properties and estimation of their antioxidative activity, bioaccessibility and bioavailability in vitro. Considerable amounts of ferulic, sinapinic and gallic acids, kaempferol, isorhamnetin and rutin were observed in the chemical ChL extract and were linked with its inhibitory effect on prostate cancer cell proliferation, motility and cellular competence for gap junctional communication. Both extracts, chemical and obtained after simulated digestion, exerted an inhibitory effect on lipoxygenase activity, paralleled by their considerable chelating, antioxidative, antiradical and reducing power. These observations indicate that phenolic ChL compounds may exert a chemopreventive and anticarcinogenic effect on oxidative stress and ROS-dependent intracellular signaling via synergic effects. The relatively high potential bioaccessibility and bioavailability of the compounds probably responsible for these effects demonstrates the suitability of ChL for dietary supplementation.

The influence of protein–flavonoid interactions on protein digestibility in vitro and the antioxidant quality of breads enriched with onion skin

Different types of breads enriched with onion skin were studied. The objectives were twofold: to show and examine protein-phenolic interactions and to discuss results concerning phenolic content, antioxidant activity and protein digestibility in the light of in vitro bioaccessibility. Phenolic contents and antiradical abilities were linked with the level of onion skin supplement however, the amounts determined were significantly lower than expected. Fortification influenced protein digestibility (a reduction from 78.4% for control breads to 55% for breads with a 4% supplement). Electrophoretic and chromatographic studies showed the presence of indigestible protein-flavonoid complexes - with molecular weights about 25 kDa and 14.5 kDa; however, the reduction of free amino group levels and the increase in chromatogram areas suggest that flavonoids also bind to other bread proteins. The interaction of phenolics with proteins affects antioxidant efficacy and protein digestibility; thus, they have multiple effects on food quality and pro-health properties.

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.

Quality and antioxidant properties of breads enriched with dry onion (Allium cepa L.) skin

The aim of the study was to investigate the effect on the antioxidant properties and sensory value of bread of adding ground onion skin (OS). For a determination of bioaccessibility and bioavailability in vitro the human gastrointestinal tract model was used. OS contained mastication-extractable quercetin (4.6 mg/g). Quercetin from OS was highly bioaccessible during in vitro conditions, but only approximately 4% of quercetin released during simulated digestion was bioavailable in vitro. The antioxidant potential of bread with OS was significantly higher than the activity noted in the control. In particular, OS addition significantly fortificated bread with bioaccessible lipid oxidation preventers and compounds with reducing and chelating abilities. The 2-3% OS addition caused significant improvement of antioxidant abilities (further increases in the OS supplement did not increase the activity of bread). Sensory evaluation showed that replacement of wheat flour in bread with up to 3% OS powder gave satisfactory consumer acceptability.

Comparison of phenolic acids profile and antioxidant potential of six varieties of spelt (Triticum spelta L.).

Phenolic acids profile and antioxidant activity of six diverse varieties of spelt are reported. Antioxidant activity was assessed using eight methods based on different mechanism of action. Phenolic acids composition of spelt differed significantly between varieties and ranged from 506.6 to 1257.4 μg/g DW. Ferulic and sinapinic acids were the predominant phenolic acids found in spelt. Total ferulic acid content ranged from 144.2 to 691.5 μg/g DW. All analyzed spelt varieties possessed high antioxidant potential. In spite of the fact that bound phenolic acids possessed higher antioxidant activities, analysis of antioxidant potential and their relationship with phenolic acid content showed that free phenolics were more effective. Eight antioxidant methods were integrated to obtain a total antioxidant capacity index that may be used for comparison of total antioxidant capacity of spelt varieties. Total antioxidant potential of spelt cultivars were ordered as follows: Ceralio > Spelt INZ ≈ Ostro > Oberkulmer Rotkorn > Schwabenspelz > Schwabenkorn.

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.

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.

Wheat bread enriched with green coffee – In vitro bioaccessibility and bioavailability of phenolics and antioxidant activity

The potential bioaccessibility and bioavailability of phenolics, caffeine and antioxidant activity of wheat bread enriched with green coffee were studied. Supplementation enhanced nutraceutical potential by improving phenolic content and lipid protecting capacity. The simulated-digestion-released phenolics (mainly caffeic acid, syringic acid and vanillic acid) from bread, also caused significant qualitative changes (chlorogenic acids were cleaved and significant amounts of caffeic acid and ferulic acid were determined). Compared to the control, for the bread with 1% and 5% of the functional component the contents of phenolics were 1.6 and 3.33 times higher. Also, an approximately 2.3-fold increase in antioxidant activity was found in bread containing 5% of the supplement. The compounds responsible for antioxidant potential have high bioaccessibility but poor bioavailability. The qualitative composition of the phenolic fraction has a key role in developing the antioxidant potential of bread; however, caffeine and synergism between antioxidants are also important considerations.

Grinding and Nutritional Properties of Six Spelt (Triticum aestivum ssp. spelta L.) Cultivars

ABSTRACT Some physical, technological, nutritional, and nutraceutical determinants of six spelt varieties were evaluated. The grains were characterized by similar grain hardness and gave similar breakage patterns on a hammer mill and relatively low grinding energy requirements. The highest protein content was determined for Spelt I.N.Z. and Schwabenkorn (155 mg/g db), whereas the lowest was for Ceralio (98 mg/g db). The total starch content in tested cultivars averaged about 500 mg/g db; however, significant differences were observed for resistant and potentially bioavailable starch. The highest starch digestibility was observed for Ostro, Schwabenspelz, and Spelt I.N.Z. (about 45%), whereas the lowest was for Ceralio (about 33%). Chemically extractable total phenolic compounds content did not differ between cultivars. When flavonoids contents were compared, however, significant differences were observed; their contents ranged from 0.61 to 2.12 mg/g db (Spelt I.N.Z. and Schwabenkorn, respectively). The ab...

Influence of Elicitation and Germination Conditions on Biological Activity of Wheat Sprouts

The influence of elicitation, time, and temperature of germination on the biological activity of wheat sprouts was studied. The total phenolics content (TPC), antioxidant activity (AA), and microbiological purity of seeds of three wheat cultivars elicited with Saccharomyces cerevisiae (Y) and Salix daphnoides bark extracts (W) and their mixture (1 : 1) germinated in different conditions were studied. The increase of germination time caused an increase the TPC and AA for all tested wheat cultivars. Germination temperature also influenced these parameters. Generally the highest values in TPC were obtained for sprouts germinated at 20°C. This tendency was found for all tested wheat cultivars. The highest values of TPC and AA were obtained after elicitation by S. daphnoides bark extract. The results of microbiological examination showed that generally for seeds germinated at lower temperature (15°C and 20°C) and during 2 and 4 days the molds were not detected and the levels of aerobic bacteria did not exceed the usually accepted limits. Taking into account both biological activity and microbiological purity of samples the best quality sprouts were in the most cases obtained for wheat germinated during four days at 20°C and elicited by W.