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The growing awareness of consumers means that new products are sought after, which, apart from meeting the basic demand for macronutrients and energy, will have a positive impact on our health. This article is a report on the characteristics of the new oil blends with a nutritious ω6/ω3 fatty acid ratio (5:1), as well as the heat treatment effect on the nutritional value and stability of the oils. Prepared oil blends were heated at 170 and 200 °C. The fatty acid composition and the changes in tocochromanols content during heating were analyzed, as well as the formation process of polar compounds and triacylglycerol polymers. During heating the highest loss of tocochromanols was characteristic of α-tocopherol and α-tocotrienol. The total content of tocopherols after heating was reduced to 1–6% of the original content in the unheated oil blends. The exception was the blend of oil with wheat germ oil, in which a high content of all tocopherols was observed in unheated and heated samples. The content of the polar fraction during heating increased on average 1.9 and 3.1 times in the samples heated at 170 and 200 °C, respectively, compared to the unheated oils. The level of the polar fraction was related to the high content of tocopherols or the presence of tocopherols and tocotrienols in the heated sample. The polymerization of triacylglycerols led mainly to the formation of triacylglycerol dimers. Trimers were observed in a small number of heated samples, especially those heated at 200 °C. Regardless of the changes in heated oils, none of the prepared blends exceeded the limit of the polar fraction content, maintaining the programmed ratio of ω6 to ω3 acids. The principal component analysis (PCA) used to define the clusters showed a large variety of unheated and heated samples. An outlier in all clusters was a blend of oil with wheat germ oil. In these samples, the degradation of tocopherols molecules and the increase of triacylglycerol polymers and the polar fraction content were the slowest.

The growing human population renders challenges for the future supply of food products with high nutritional value. Here, we enhanced the functional and nutritional value of biscuits, a popular sweet snack, by replacing the wheat flour with 2%, 6%, or 10% (w/w) cricket powder. Consumer acceptance ratings for reference and 2% augmented cookies were comparable, whereas the higher levels of enhancement received inferior consumer scores. This relatively small change in biscuit recipe provided significant and nutritionally desirable enhancements in the biscuits, observed in a series of analyses. An increase in the protein content was observed, including essential amino acids, as well as minerals and fat. This conversion also affected the physical properties of the biscuits, including hardness, and water molecular dynamics measured by 1H NMR. Cricket powder-augmented biscuits join the line of enhanced, functionally superior food products. This and similar food augmentation provide a viable scenario to meet the human food demands in the future.

Leaves of the Ginkgo biloba L. have been identified as a source of bioactive compounds and their consumption may lead to the improvement of the brain function. During two vegetation periods, extracts of green and yellow leaves of Ginkgo biloba were analyzed for their chemical constituents and health properties. Samples were analyzed via HPLC and GC methods for the presence and content of phytochemicals. The antioxidant effect towards DPPH and ABTS radicals was studied. The antioxidant activity of samples was measured in Rancimat and Oxidograph tests along with the effectiveness of samples as inhibitors against cholinesterase. The content of individual phytochemicals was found to depend on the harvesting period and type of solvent used in the extraction process. Gingko yellow leaf extracts showed highest radical-scavenging activity as well as cholinesterase inhibition activity, and can be a valuable raw material to produce extracts possessing high cholinesterase inhibition activity.

Nowadays there are many varieties of pumpkins differing in oil content in seeds and its composition. The aim of this study was analysis and comparing fatty acids composition, tocopherols and oil content in seeds of 31 pumpkin varieties. Oils were extracted from the pumpkin seeds, which belong under one of species: Cucurbita maxima, Cucurbita moschata, Cucurbita pepo or Cucurbita pepo var. turbinata. The highest content of oil was found in Green Hubbard (32.69%) variety. The highest content of PUFA and MUFA achieved for Table Queen variety (79.09%) and for Buttercup variety (29.73%), respectively. The predominant fatty acid was linoleic acid (49.63–78.82%), following by oleic acid (8.55–29.73%). The n6:n3 ratio ranged from 59.91 (Yuxijiangbinggua variety) to 607.93 (Cream of the Crop variety). The total tocopherols content was between 0.65 (for Yuxijiangbinggua) and 41.06 mg 100 g−1 (for Snowball). γ-tocopherol was a predominant fraction in all varieties with the highest content on the level 37.52 mg 100 g−1 (Snowball). Potential application areas of examined pumpkin seed oil are consumption, cooking, producing functional food, medicines, but also biolubricants and biofuel. It is assumed a diversity of content and composition of examined pumpkin seed oil was the result of genetic factors.

Background: Rosemary (Rosmarinus officinalis) contains active substances that have desirable properties for industrial and herbal medicine applications, e.g., essential oils (1.5–2.5%), tannins, flavonoids, triterpenes, saponins, resins, phytosterols, rosmarinic acid and many others. The aim of this study was to determine the influence of rosemary extract and 20% rapeseed oil substitution for animal fat on storage changes and inhibition of cholinesterases in liver pâté. Results: Preliminary research showed that rosemary extract exhibited antioxidative activity in the system of accelerated Rancimat and Oxidograph tests. Then, rosemary extract was used as an ingredient in liver pâté. During the experiment, meat samples were refrigerated and tested on days 1, 5, 8, 12 and 15 after production. The study proved that the substitution of 20% of animal fat with rapeseed oil decreased the content of saturated acids and increased the content of monoenic fatty acids by approximately 5% and polyene fatty acids by 40%. Conclusions: In addition to antioxidative activity, the rosemary extract affected the health-promoting value of the samples, which inhibited cholinesterase activity during the entire storage period. The extract inhibited AChE more than BChE.How to cite: Bilska A, Kobus-Cisowska J, Kmiecik D, et al. Cholinesterase inhibitory activity, antioxidative potential and microbial stability of innovative liver pâté fortified with rosemary extract (Rosmarinus officinalis). Electron J Biotechnol 2019;40. https://doi.org/10.1016/j.ejbt.2019.03.007 Keywords: Animal fat, Antioxidants, Cholinesterase, Essential oils, Liver pâté, Peroxide value, Rapeseed oil, Rosemary extract, Rosmarinus officinalis, TBARS

This paper presents a study on the antiradical properties of red fruits commonly consumed in Europe, i.e. strawberry (Fragaria ananasa), raspberry (Rubus ideaus), blackberry (Rubus fruticosus), cranberry (Vaccinium macrocarpon) and pomegranate (Punica granatum) extracts by various in vitro tests as well as the determination of qualitative and quantitative features of their phenolic compounds. Our results indicated richness of red fruits in phenolic compounds and variability of their chemical mixtures dominated generally by anthocyanins, ellagic acid and their derivatives. The selected fruit extracts exhibited notable antiradical activity by DPPH, ABTS, ORAC and PCL assays with significant correlation to phenolic content and remarkable influence of the chemical composition. This investigation indicated that the red fruits examined constitute prosperous natural sources of antiradical substances of high value which would benefit the product quality and consumers’ health.

Cricket powder, described in the literature as a source of nutrients, can be a valuable ingredient to supplement deficiencies in various food products. Work continues on the implementation of cricket powder in products that are widely consumed. The aim of this study was to obtain gluten-free bread with a superior nutritional profile by means of insect powder addition. Gluten-free breads enriched with 2%, 6%, and 10% of cricket (Acheta domesticus) powder were formulated and extensively characterized. The nutritional value, as well as antioxidant and β-glucuronidase activities, were assessed after simulated in vitro digestion. Addition of cricket powder significantly increased the nutritional value, both in terms of the protein content (exceeding two-, four-, and seven-fold the reference bread (RB), respectively) and above all mineral compounds. The most significant changes were observed for Cu, P, and Zn. A significant increase in the content of polyphenolic compounds and antioxidant activity in the enriched bread was also demonstrated, moreover, both values additionally increased after the digestion process. The total polyphenolic compounds content increased about five-fold from RB to bread with 10% CP (BCP10), and respectively about three-fold after digestion. Similarly, the total antioxidant capacity before digestion increased about four-fold, and after digestion about six-fold. The use of CP also reduced the undesirable activity of β-glucuronidase by 65.9% (RB vs. BCP10) in the small intestine, down to 78.9% in the large intestine. The influence of bread on the intestinal microflora was also evaluated, and no inhibitory effect on the growth of microflora was demonstrated, both beneficial (Bifidobacterium and Lactobacillus) and pathogenic (Enterococcus and Escherichia coli). Our results underscore the benefits of using cricket powder to increase the nutritional value and biological activity of gluten-free food products.

The process of deep fat frying is the most common technological procedure applied to rapeseed oil. During heat treatment, oil loses its nutritional properties and its original consumer quality is lowered, which is often impossible to determine by organoleptic assessment. Therefore, the aim of the study was to correlate markers of the loss of the nutritional properties by rapeseed oil related to the frying time and the surface area of contact with oxygen with changes in the profile of volatile compounds. The investigations involved the process of 6-, 12-, and 18-h heating of oil with a surface-to-volume ratio (s/v ratio) of 0.378 cm&minus, 1, 0.189 cm&minus, 1, and 0.126 cm&minus, 1. Samples were analysed to determine changes in the content of polar compounds, colour, fatty acid composition, iodine value, and total chromanol content. The results were correlated with the emission of volatile compounds determined using gas chromatography and an electronic nose. The results clearly show a positive correlation between the qualitative degradation of the oil induced by prolonged heating and the response of the electronic nose to these changes. The three volumes, the maximum reaction of the metal oxide semiconductor chemoresistors, and the content of polar compounds increased along the extended frying time.

The oxidative stability of oilseeds is crucial for their technological/nutritional quality and shelf life. This research aimed to evaluate the effect of thermal pre-treatment (steaming and roasting under various time/temperature conditions) on flaxseed oil and protein stability. The monitoring of changes in oil oxidation in situ and protein profiles (SDS-PAGE) and analysis of the antiradical activity of ethanolic and aqueous fractions were included in the study.; Results: Flaxseed stability during storage was considerably affected by thermal pre-treatment conditions. Dynamics of oil oxidation was accelerated at 160 °C and 180 °C but slowed at 200 °C. Influence of pre-treatment conditions on the antiradical activity of the aqueous fraction was clearly observed and no effect concerning the ethanolic fraction was found. The most significant changes in protein profile of 200 °C-roasted flaxseed were found with the observed disappearance of 19 kDa protein. A treatment-dependent decrease in the 13 kDa protein was also detected. Based on the aqueous extract protein profiles, roasting conditions were found to be crucial for protein extractability.; Conclusions: The study has broadened knowledge of the consequences of flaxseed thermal treatment. The deterioration of flaxseed oil oxidative stability is shown. The changes of 19 and 13 kDa proteins suggest their sensitivity to thermally induced aggregation and/or cross-link. © 2018 Society of Chemical Industry.; © 2018 Society of Chemical Industry.

The purpose of this study was to design the formula and antioxidant potential of gluten-free oat drinks fortified with bioactive plant components. The paper describes the use of three preparations of plant origin: yellow tea leaf extract, mulberry extract and steviol glycosides from stevia leaves. Analyses of the oat drinks basic composition – including proteins, lipids, carbohydrates, dietary fiber fractions and antioxidant properties with DPPH, ABTS, ORAC and FRAP assays were conducted. Tea extract with steviosides oat drink showed the highest total phenolic concentration and the highest antioxidant activity followed by stevia and mulberry oat drink, whereas stevia oat drink showed the lowest phenolics level and weakest antioxidant activity. Moreover, the applied plant components showed moderate ability to influence the sensory values of the fortified oat drinks. The results demonstrate that tea, stevia and mulberry preparations applied in oat drinks enhanced antioxidant potential and might be a natural source of antioxidant components.

Cardiovascular diseases constitute a significant public health problem. It is estimated that they cause approx. 30% all deaths worldwide. Many factors are of importance for the development of cardiovascular diseases, with human nutrition being a modifiable risk factor. Many compounds are supplied with the diet, causing definite effects, both positive and negative. Carotenoids are substances with a potential positive effect. Literature data indicate that these compounds exhibit a broad spectrum of health-promoting effects. It is believed that they may inhibit the development of cardiovascular diseases. This paper presents results of current studies, with the synthesis providing an answer to the question whether carotenoids exhibit a cardioprotective properties.

The aim of the study was to analyse the content and composition of products of thermal degradation of triacylglycerols (TAG) in 21 commercial frozen fried potato products, including traditional and corrugated French fries, potato wedges, potato slices and potato balls. Seventeen products were offered both to foodservice and households and four only for foodservice. The total content of polar compounds, composition of fatty acids and products of thermal degradation of TAG were analysed by means of gas chromatography (GC) and size-exclusion chromatography (HPSEC). The products were prepared for analysis using palm and sunflower oil. The analysis of polar and nonpolar oil fractions in the products showed that the polar fraction contained much more polymers than the nonpolar fraction. The polar fraction also contained more advanced products of polymerisation such as trimers and oligomers. The composition and the content of products of thermal degradation of oil depended on the type of oil used for frying rather than the type of fried potato product. Most of the products prepared with palm oil contained less dimers, trimers, and oligomers of TAG than the sunflower oil products. The content of polymers in the samples ranged from 13.3 to 265 mg/100 g of products.

The consumption of plant sterols is reported to have a beneficial effects on human health, i.e. phytosterols are known for their cholesterol-lowering properties. Whereas, they are prone to oxidation and currently there is ongoing worldwide research aimed at the biological effect of phytosterol oxides. In this study volatile compounds formed during thermal degradation of stigmasteryl esters were identified. The research was conducted using standards of stigmasterol, fatty acids and stigmasteryl esters as well as fat enriched with stigmasteryl esters which were thermally treated at 60 °C and 180 °C for 12 h. Volatile compounds were characterised by SPME-GC-MS. Among the volatiles formed during heating of stigmasteryl esters aldehydes, ketones, alcohols and hydrocarbons were found. The mechanism of the formation of volatile compounds from sterol esters was related to oxidation of steryl and fatty acid moieties. In particular, 2-methyl-3-pentanone and 5-ethyl-6-methyl-3-hepten-2-one were identified as unique degradation products formed from degradation of the steryl moiety specifically, and a mechanism of their formation was suggested. Both volatiles could be a good indicator of thermo-oxidative degradation of functional food products enriched in phytosterols and their esters.

This study investigated the effect of antioxidants on lipid stability of frozen-stored meat products. Buckwheat hull extract was used to enrich fried meatballs made from ground pork. During 180-d storage of meat products, lipid oxidation (peroxide and 2-thiobarbituric acid reactive substances [TBARS] value) was periodically monitored. The results were compared with butylated hydroxytoluene (BHT). The addition of antioxidants decreased lipid oxidation in stored meatballs. The highest ability to control peroxide and TBARS values was demonstrated for buckwheat hull extract. Moreover, buckwheat hull extract showed a higher 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity as well as higher Fe(II) ion chelating ability, as compared with BHT. The total content of phenolic compounds are highly correlated to the individual polyphenols in extract of buckwheat hull, among which the following were assayed: 3,4-dihydroxybenzoic acid, 4-hydroxybenzoic acid, gallic acid, isovanillic acid and p-coumaric acid, and flavonoids: isoorientin, quercetin, quercetin 3-d-glucoside, rutin, and vitexin. These results indicate that plant extracts can be used to prolong shelf life of products by protecting them against lipid oxidation and deterioration of their nutritional quality.

The aim of the present study was to develop a novel type of probiotic chocolate with the additive Bacillus coagulans bacteria and determine the concentration of polyphenols and their bioaccessibility. The manufactured chocolate possessed significantly higher concentrations of polyphenols than the control sample. The sensory profiles of the tested probiotic chocolate were similar to those of the control sample. In future, the probiotic chocolate could be regarded as a functional food product by chocolate producers.

Phytosterols are naturally occurring substances in foods of plant origin that have positive effects on the human body. Their consumption can reduce the level of low density lipoprotein (LDL) cholesterol. The presence of unsaturated bonds in their structure leads to their oxidation during production, storage, and thermal processes. The aim of the study was to determine how the degree of unsaturation of rapeseed oil affects the oxidation of phytosterols in oil during 48 h of heating. In all not-heated oils, the dominant groups of oxyphytosterols were 7&alpha, and 7&beta, hydroxy sterols. During 48 h of heating, the rapid decrease of phytosterols&rsquo, levels and the increase of the content of oxyphytosterols were observed. The main dominant group in heated samples was hydroxy and epoxy sterols. Despite differences in fatty acid composition and content and composition of single phytosterols in unheated oils samples, the total content of oxyphytosterols after finishing of heating was on a similar level for each of the tested oils. This showed that the fatty acid composition of oil is not the only factor that affects the oxidation of phytosterols in foods during heating.

This study evaluated the effect of adding a new step, termed conditioning, to the traditional processing of leaves from Morus alba var. zolwinska wielkolistna grown in Poland (WML-P). This step, modeled on tea leaves processing, was conducted in a controlled environment on a semi-technical scale. The primary goal was to evaluate the effect of the WML-P conditioning for 1&ndash, 4 h at 32&ndash, 35 &deg, C on the content of bioactive compounds (total phenolics, phenolic acids, flavonols, 1-deoxynojirimycin) and antioxidant activity (radical scavenging against DPPH, antioxidant capacity, chelating activity and ferric reducing antioxidant potential) of the lyophilized extracts. For the first time WML-P extracts content was comprehensively characterized by assessing dietary fiber fractions, fatty acids, amino acids, macro- and microelements and chlorophyll content. Compared to the traditional process, adding the conditioning step to WML-P processing resulted in an increased total phenolics content, radical scavenging capacity, ability to quench 2,2-diphenyl-1-picrylhydrazyl (DPPH&middot, ) and iron-chelating ability in the lyophilized extracts. The beneficial effect depended on conditioning time. The highest flavonols and phenolic acids content were found after 2-h conditioning. We concluded that adding a 2-h conditioning step to traditional WML-P processing results in getting WML-P lyophilized extract with increased bioactive compounds content and high antioxidant activity.

Thermo-oxidative changes were assessed during simulated storage and frying of refined rapeseed oil (RRO). When RRO was heated at 60 and 180 °C for 8h phytosterols content decreased by 10 and 40%, however tocopherols disappeared by 7 and 30%, respectively. The oxyphytosterols content increased during first 2 h of heating at both temperatures to 55 and 211 μg/g, however extended heating resulted in reduction of these compounds to 38 and 169 μg/g, respectively. Total polar compounds were observed in RRO heated at 60 and 180 °C for 8 h at 12 and 42%, respectively. Polar compounds were consisted by: free fatty acids (FFA), low molecular weight (LMW) compounds including monomers, while non-polar fraction contained LMW and monomers formed during heating at 60 °C. Non-polar fraction formed during heating of RRO at 180 °C for 8h which contained monomers and LMW compounds. Among volatile compounds, four carbonyls and an alcohol were detected in heated RRO.

Phytosterols and their esters are often used as functional ingredients in food products due to its lowering blood cholesterol properties. Products containing phytosterols and its esters are recommended for direct consumption, cooking, baking and frying, however during food preparation it is possible thermo-oxidative degradation is possible. Unsaturation of fatty acid present in steryl ester may further stimulates degradation. Free stigmasterol degraded faster than its esters, even with linoleic acid attached. The highest amount of degradation products was observed for free stigmasterol, followed by esters with linoleic and oleic acids. Polar dimers were fund in all heated samples, although for free stigmasterol heated at 60 °C were not detected. Whereas non-polar dimers were observed only in heated stigmasterol. Degradation of esterified stigmasterol generated degradation products with lower cytotoxicity.

The aim of the study was to analyze the influence of natural antioxidants on polymerization of partially hydrogenated rapeseed oil heated in 170°C for 40h. In the research ethanolic extracts of green tea leaves (China Lung Ching), yellow tea leaves (China Kakecha), cranberry, blackberry, and lime were used. The yellow and green tea extracts were characterized by the highest content of total polyphenol and antioxidant activity. Polymers of triacylglycerols were found only in the polar fraction of heated oil. During heating, the increase of dimers, trimers, and oligomers was observed. However, it was dependent on the used additives and not directly related to the content of phenolic compounds and their antioxidant activity. The final content of polymers in oil samples increased in the fallowing order: green tea

Common hop (Humulus lupulus L.) has significant health-promoting properties. Hop cones contain resins, essential oils, proteins, polyphenols, lipids, waxes, and cellulose. Hop extracts include bioactive compounds such as polyphenolic compounds (phenolic acids, and flavonols), and chlorophylls. The aim of this study was to compare the pro-health potential of hop cone extracts obtained from three cultivars (Magnum, Lubelski, and Marynka). The results showed that the cones of Magnum cultivar demonstrated the highest biological activity. The sum of phenolic acids and flavonols in ethanol extract was the highest for this variety and was equal 4903.5 &micro, g/g dw. Ethanol extracts of Magnum cultivars showed the highest degree of iron ion chelation (55.43&ndash, 88.76%) as well as the activity against 1,1-diphenyl-2-picrylhydrazyl radical (4.75 mmol Tx/g dw). Hop cone extracts as cholinesterase inhibitors showed high potential for aqueous variants. In terms of antimicrobial activity, all investigated extracts demonstrated strong inhibition against Staphylococcus aureus and Staphylococcus epidermidis, with the Magnum cultivar showing the strongest inhibition. Owing to the biofunctional features of hop cone, it can be concluded that it is an attractive raw material with pro-health potential that can be used much more widely in food technology. However, it should be noted that toxicological tests and in vitro tests must be carried out before the raw material is used in food production.

Background Asparagus officinalis has a high nutritional value. Asparagus is rich in a number of bioactive compounds, mainly flavonoids (quercetin), glutathione, vitamin C, vitamin E, fructans (inulin and fructooligosaccharides) and phytosterols (b-sitosterol). These compounds may play an important role in human health. The purpose of this study was to examine the antioxidant potential and polyphenol composition of white, pale-colored and green asparagus spears of different cultivars. Methods Investigations were conducted on different asparagus spear extracts. The study included three colors of asparagus (white, pale-colored and green) from five different cultivars subjected to the ethanol extraction procedure. Total phenolic content was also determined by the Folin-Ciocalteu method. Polyphenol (phenolic acids and flavonols) composition was estimated using the HPLC method. The antioxidant properties of extracts were examined using DPPH, ABTS and metal ion chelating assays. Results The highest contents of phenolic and flavonoids were observed in green asparagus from Grolim and the lowest in pale-colored asparagus from Gyjmlin. It was found that both the color of asparagus and the cultivar had a significant effect on the composition of phenolic acid and flavonols. Radical scavenging activity toward DPPH• and ABTS was highest for green asparagus cv. Grolim and Eposs. The greatest number of Fe ions was chelated by samples of green asparagus cv. Grolim and Huchel's Alpha and pale-colored asparagus cv. Huchel's Alpha. Conclusions It was shown that the antioxidant activity of asparagus spears measured by antiradical and chelating activity test depends on variety and color. The highest activity was found in green asparagus and the lowest was identified in white asparagus extracts. It has also been clarified that changes in flavonol and phenolic acid composition and increases in their diversity depends on growing with sunlight and variety. Asparagus can provide a valuable source of phenolic compounds in the human diet.

The aim of this study was to estimate the effect of natural and synthetic antioxidants in protecting phytosterols during heating at 180 °C. Green tea extract, rosemary extract, a mix of tocopherols from rapeseed oil, a mix of synthetic tocopherols, phenolic compounds extracted from rapeseed meal, sinapic acid and BHT were used. After 4 h of heating in oxygen atmosphere β-sitosterol and campesterol oxidation products (7α- and 7β-hydroxysterol, 5α,6α- and 5β,6β-epoxysterol, 7-ketosterol and triols) were estimated by GC. Total content of phytosterol oxidation products in samples ranged from 137 to 374 mg/kg of sample. The effectiveness of antioxidants decreased in the following order: synthetic tocopherols > green tea extract > natural tocopherols from rapeseed oil > rosemary extract > phenolic compounds extracted from rapeseed meal > sinapic acid > BHT.

Antioxidants are substances that can reduce negative changes in fat. Many antioxidants are very effective during storage, but during heating they lose their properties. It is very important to find antioxidants that will be stable at high temperatures and protect fat throughout the entire frying process. The aim of this study was to estimate the effect of natural and synthetic antioxidants on changes in phytosterols of rapeseed oil during heating. Oil with antioxidants was heated at 180 °C for 4 h in a Rancimat ® and in an Oxidograph ® . Ethanol extract of rosemary, ethanol extract of green tea, and BHT were used in the study. The contents of phytosterols (sitosterol, campesterol, avenasterol, brassicasterol, stigmasterol) and oxyphytosterols (7α- and 7β-hydroxysterol, 5α,6α- and 5β,6β-epoxysterol, 7-ketosterol and triols) were estimated by gas chromatography. In all samples with antioxidants, a lower decrease of phytosterols and a lower increase of total oxyphytosterols were observed in comparison with the control sample (without antioxidant). The antioxidant effect depends on the type of the antioxidant and the heating conditions. The best results were observed in samples with natural antioxidants. BHT was a substance that protected phytosterols as well, but not as effectively as the other antioxidants.

Antioxidants have become one of the hottest topics in the modern food industry, not only as food additives preventing oxidative changes, but also as food components acting in vivo after ingestion. According to their mechanisms of activity, antioxidants have been divided into two basic groups: primary antioxidants or donators, so-called preventive antioxidants, and secondary antioxidants or the acceptors, the so-called chain-breaking antioxidants. In recent years, researchers have turned their attention towards phenolic compounds, secondary metabolites of the plant world, which are highly bioactive. Today, the food industry needs to search for other innovative sources of antioxidants that could be consumed everyday and that would lead to a healthier life, that would be acceptable to consumers, safe, with a high potential, cheap, and biologically active in low concentrations.

This paper presents a study on development of functional food products containing green and yellow tea leaves. The results indicated that green and yellow tea are significant tools in the creation of the nutritional value, antioxidative potential and stability of the lipid fraction of cookies. Tea-fortified cookies showed considerably higher contents of dietary fiber, especially hemicellulose and insoluble fractions, and were characterized by significantly higher antioxidant potential associated with their phenolics content. Results of ABTS, DPPH, ORACFL and PCL assay showed significantly higher antioxidant potential of tea cookies, highest for yellow tea. The antioxidative potential of applied teas was significant in terms of the inhibition of hydroperoxide content, while formation of secondary lipid oxidation products was less spectacular. It is concluded that tea leaves could be widely used as a source of polyphenols with high antioxidative potential, as well as fiber; thus introducing numerous health benefits for the consumer.

The aim of the study was to assess the potential applicability of natural antioxidants in the stabilisation of phytosterols. A mixture of β-sitosterol and campesterol was incorporated into triacylglycerols (TAGs). The following antioxidants were added to the prepared matrix: green tea extract, rosemary extract, a mix of tocopherols from rapeseed oil, a mix of synthetic tocopherols, phenolic compounds extracted from rapeseed meal, sinapic acid and butylated hydroxytoluene (BHT). Samples were heated at a temperature of 180 °C for 4 h. After the completion of heating, the losses of phytosterols were analysed, as well as the contents of β-sitosterol and campesterol oxidation products. The total content of phytosterol oxidation products in samples ranged from 96.69 to 268.35 μg/g of oil. The effectiveness of antioxidants decreased in the following order: phenolic compounds from rapeseed meal>rosemary extract>mix of tocopherols from rapeseed oil>mix of synthetic tocopherols>green tea extract>sinapic acid>BHT.