The Antioxidant Properties of Selected Varieties of Pumpkin Fortified with Iodine in the Form of Potassium Iodide and Potassium Iodate.

This study aimed to investigate the use of selected pumpkin varieties as carriers of potassium iodide (KI) and potassium iodate (KIO3) at different concentrations (2.3, 0.23, and 0.023 mg/100 g). It was hypothesized that the concentrations and form of iodine fortification in pumpkins affect the antioxidant activity of pumpkins. The results showed a high recovery of the introduced iodine in all pumpkin varieties after drying, as well as high iodine stability during storage, especially for KIO3. However, statistical analysis confirmed a relationship between the forms and concentration of iodine and the ABTS cation radical and the DPPH radical test results. In the systems with iodine concentration at 0.023 and 0.23 mg/100 g, the antioxidant activity did not change. However, for all pumpkin varieties fortified with a KIO3 concentration at 3.9 mg/100 g (2.3 mg/100 g of iodine), a statistically significant decrease in free-radical scavenging was confirmed. Therefore, for maximum effectiveness in pumpkin's free-radical scavenging indices, it is suggested to introduce iodine in the form of KI and KIO3, but in controlled concentrations. However, KIO3 should be added at a maximum amount of 0.39 mg/100 g.

Influence of Nitrogen Fertilizer on the Antioxidative Potential of Basil Varieties (Ocimum basilicum L.).

Total phenolic content (TPC) in extracts of basil depended on the cultivar and type of fertilization used in cultivation. TPC was determined spectrophotometrically with the Folin−Ciocalteu reagent. The antioxidant activity of extracts was analyzed by scavenging of DPPH and ABTS radicals, on the basis of metal chelating ability (MetChel) and ferric reducing antioxidant power (FRAP). The greatest TPC was determined in the purple cultivars­141.35 and 165.44 mg gallic acid/g d.m. for fertilized with ammonium nitrate (NH4NO3) and ammonium sulfate ((NH4)2SO4), respectively. Their extracts had the greatest antioxidant capacity in the majority of the methods used. The results varied depending on the modelling system used. The amount of polyphenols in individual basil cultivars differed significantly (p < 0.05) depending on the fertilization used in the culture. Regarding TPC, DPPH, ABTS, FRAP, and MetChel variables, we observed a significant effect for the applied cultivation. In the case of MetChel factor, lower results of all investigated basil species were observed for cultivation with ammonium sulfate. PCA demonstrated in the present study shows that Sweet and Cinnamon Basil samples cultivated with ammonium nitrate create a separated group. We recommend cultivation with ammonium sulfate fertilizers for these varieties of basil. The high content of phenolic compounds demonstrated in Sweet and Cinnamon Basil cultivated with ammonium sulfate, and thus associated antioxidant activity, indicates that it can constitute a valuable source for bioactive compounds in a balanced diet.

Innovative Application of Phytochemicals from Fermented Legumes and Spices/Herbs Added in Extruded Snacks.

A trend related to adding legume seeds to various products has been observed. This work aimed to use fermented red bean/broad bean seeds and their hulls to produce extruded snacks with more beneficial nutritional properties and good sensory quality. Extruded snacks containing fermented ground seeds (50%) or hull (10%) of red bean/broad bean and corn grits with the addition of selected herbs/spices (0.5%) were prepared. The chemical composition, phenolic profile, antioxidant activity, and sensory quality were analysed. The results showed that the protein content ranged from 9 to 22.9 g 100 g-1, phenolic compounds ranged from 3.97 to 12.80 mg 100 g-1 (with the addition of herbs/spices, even up to 62.88 mg 100 g-1), and antioxidant activities ranged from 4.32 to 10.23 Trolox g-1 (ABTS assay), depending on the type of fermented materials. The addition of ground seeds/hull did not influence the consumer desirability, whereas the addition of selected herbs/spices, particularly lovage, increased it. The application of fermented red bean and broad bean seeds and their hulls, as part of the assumptions of the planetary diet, enabled enrichment of extruded corn products, which are often consumed by vegans and vegetarians, with nutritionally valuable ingredients.

Sensory Analysis in Assessing the Possibility of Using Ethanol Extracts of Spices to Develop New Meat Products.

The food industry has endeavoured to move toward the direction of clean labelling. Therefore, replacing synthetic preservatives with natural plant extracts has gained significant importance. It is necessary to determine whether products enriched with such extracts are still accepted by consumers. In this study, consumer tests (n = 246) and sensory profiling were used to assess the impact of ethanol extracts of spices (lovage, marjoram, thyme, oregano, rosemary, and basil; concentration 0.05%) on the sensory quality of pork meatballs and hamburgers. The desirability of meat products with spice extracts to consumers depended on the added extract. The highest scores were for products with lovage extract, whose sensory profile was the most similar to the control sample without the addition of an extract (with higher intensity of broth taste compared with the others). Products with rosemary and thyme extracts were characterised by lower desirability than the control. This was related to the high intensity of spicy and essential oil tastes, as well as the bitter taste in the case of products with thyme. The studied extracts of spices allow for the creation of meat products (meatballs and hamburgers) with high consumer desirability, however, the high intensity of essential oil and spicy tastes might be a limitation.

Soy Preparations Are Potentially Dangerous Factors in the Course of a Food Allergy.

The special properties of soy preparations make them common additives for food production and can be dangerous for sensitive individuals. Our aim was to check consumers' awareness of potential risks of soy preparations added to numerous food products, depending on respondents' education, and to evaluate immunoreactive properties of chosen soy preparations. A personal questionnaire was used. Respondents (n = 251) were aged 23-28 years old, lived in Poland, and were graduates or students in their last year of food technology, medicine, and university of technology. The slot blot and Western blotting methods were used to mark immunoreactivity of soy preparations. It was shown that most respondents often or usually read labels of food products they buy. The surveyed indicated protein is the allergenic component in soy. Almost half of them were of the opinion that hydrolysis removes the allergenic properties of soy. Most of the medical students surveyed thought that people allergic to soy may consume products that contain soy preparations. The analytical results indicated that soy preparation contained protein fractions that were immunoreactive with sera of allergenic patients. It was proven that preparations, even hydrolysates, contain immunoreactive proteins that may be the source of hidden allergens, even though they are not recognized as dangerous by well-educated respondents.

Aloe vera (L.) Webb.: Natural Sources of Antioxidants - A Review.

Many studies have proved that bioactive components of Aloe vera have an anti-inflammatory effect and support lipid and carbohydrate metabolism, helping to maintain normal sugar and cholesterol levels in blood and normal body weight. When aloe is applied externally, it accelerates the regeneration of the damaged skin. Aloe contains antioxidants, which may increase the shelf-life and nutritional value of food; therefore, it is widely used in cosmetic, pharmaceutical and food industry. An antioxidant activity was shown for leaf's skin, flowers and gel of aloe. In this work the future of A. vera as effective antioxidants is primarily discussed and expected trends are summarised. Furthermore, the bioactive components and the health-promoting effects of A. vera are investigated.

The effect of antioxidants on quantitative changes of lysine and methionine in linoleic acid emulsions at different pH conditions.

BACKGROUND: Plants are an important source of phenolic compounds. The antioxidant capacities of green tea, thyme and rosemary extracts that contain these compounds have been reported earlier. However, there is a lack of accessible information about their activity against lipid oxidation in emulsions and inhibit the interaction of lipid oxidation products with amino acids. Therefore, the influence of green tea, thyme and rosemary extracts and BHT (butylated hydroxytoluene) on quantitative changes in lysine and methionine in linoleic acid emulsions at a pH of isoelectric point and a pH lower than the isoelectric point of amino acids was investigated. METHODS: Total phenolic contents in plant extracts were determined spectrophotometrically by using Folin-Ciocalteu's reagent, and individual phenols by using HPLC. The level of oxidation of emulsion was determined using the measurement of peroxides and TBARS (thiobarbituric acid reactive substances). Methionine and lysine in the system were reacted with sodium nitroprusside and trinitrobenzenesulphonic acid respectively, and the absorbance of the complexes was measured. RESULTS: Extract of green tea had the highest total polyphenol content. The system containing antioxidants and amino acid protected linoleic acid more efficiently than by the addition of antioxidants only. Lysine and methionine losses in samples without the addition of antioxidants were lower in their isoelectric points than below these points. Antioxidants decrease the loss of amino acids. The protective properties of antioxidants towards methionine were higher in a pH of isoelectric point whereas towards lysine in pH below this point. CONCLUSIONS: Green tea, thyme and rosemary extracts exhibit antioxidant activity in linoleic acid emulsions. Moreover, they can be utilized to inhibit quantitative changes in amino acids in lipid emulsions. However, the antioxidant efficiency of these extracts seems to depend on pH conditions. Further investigations should be carried out to clarify this issue.

The Effect of Buckwheat Hull Extract on Lipid Oxidation in Frozen-Stored Meat Products.

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.

Stabilisation of phytosterols by natural and synthetic antioxidants in high temperature conditions.

The aim of the study was to assess the potential applicability of natural antioxidants in the stabilisation of phytosterols. A mixture of ß-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 ß-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.

Effect of boiling in water of barley and buckwheat groats on the antioxidant properties and dietary fiber composition.

In recent years, there has been an ever-increasing interest in the research of polyphenols obtained from dietary sources, and their antioxidative properties. The purpose of this study was to determine the effect of boiling buckwheat and barley groats on the antioxidant properties and dietary fiber composition. Antioxidative properties were investigated using methyl linoleate model system, by assessing the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity and metal chelating activity. The results were compared with butylated hydroxytoluene (BHT). Raw barley and buckwheat groats extracts showed higher DPPH scavenging ability compared to boiled barley and buckwheat groats extracts. Raw barley groats extract exhibited higher antioxidant activity than boiled groats extract in the methyl linoleate emulsion. Higher chelating ability in relation to Fe (II) ions was observed for boiled groats extracts as compared to raw groats extracts. BHT showed small antiradical activity and metal chelating activity, while showing higher antioxidative activity in emulsion system. The analysis of groats extracts using HPLC method showed the presence of rutin, catechin, quercetin, gallic, p-hydroxybenzoic, p-coumaric, o-coumaric, vanillic, sinapic, and ferulic acids. Differences in the content of dietary fiber and its fractions were observed in the examined products. The highest total dietary fiber content was detected in boiled buckwheat groats, while the lowest - in boiled barley groats. The scientific achievements of this research could help consumers to choose those cereal products available on the market, such as barley and buckwheat groats, which are a rich source of antioxidative compounds and dietary fiber.

Effect of ethanolic flax (Linum usitatissimum L.) extracts on lipid oxidation and changes in nutritive value of frozen-stored meat products.

BACKGROUND: Flaxseed (Linum usitatissimum L.) is an important source of phenolic compounds, mainly lignans. Antioxidant capacities of flaxseed extracts that contain the compounds have been reported earlier. However, there is a lack of accessible information about their activity against lipid oxidation in meat products. Therefore, the effect of ethanolic flaxseed extracts (EFEs) on lipid stability and changes in nutritive value of frozen-stored meat products (pork meatballs and burgers) was determined. MATERIAL AND METHODS: EFEs from three Polish flax varieties (Szafir, Oliwin, Jantarol) were applied in the study. During 150-day storage of meat products, the lipid oxidation (peroxide and TBARS value) and thiamine retention were periodically monitored, alongside with methionine and lysine availability and protein digestibility. RESULTS: The addition of EFEs significantly limited lipid oxidation in stored meatballs and burgers. EFE from brown seeds of Szafir var. was superior to the others from golden seeds of Jantarol and Oliwin. Moreover, the extracts reduced changes in thiamine and available lysine content, as well as protein digestibility, during storage time. The effect of EFE addition on available methionine retention was limited. CONCLUSION: The ethanolic flaxseed extracts exhibit antioxidant activity during frozen storage of meat products. They can be utilized to prolong shelf-life of the products by protecting them against lipid oxidation and deterioration of their nutritional quality. However, antioxidant efficiency of the extracts seems to depend on chemical composition of raw material (flax variety). Further investigations should be carried on to explain the issue.

Thiamine losses during storage of pasteurised and sterilized model systems of minced chicken meat with addition of fresh and oxidized fat, and antioxidants.

BACKGROUND: The aim of the study was to determine the effect of pasteurisation and sterilization of model systems of minced chicken meat in the presence of low or high-oxidised pork lard, soy and sunflower oil, as well as casein hydrolysate and rosemary extract, on losses of thiamine in model systems. METHODS: In the samples, the thiamine content was analysed periodically by thiochromium method, as well as rate of lipid oxidation based on measurement of peroxide value (PV) by iodometric method and p-anisidine value (AV) by spectrophotometric method. RESULTS: It was observed that the thiamine losses in model systems of minced chicken after pasteurisation (61-71%) were higher than after sterilization (57-67%). Introduction of high-oxidised fat increased the total thiamine losses both during thermal processing and storage of meat samples (to 23%). A strong relationship was established between thiamine losses and rate of fat oxidation. The lowest total thiamine losses were observed in the samples with low-oxidised pork lard. Antioxidant addition (rosemary extract or casein hydrolysate) into meat samples limited the thiamine losses. However, the effect depended on oxidation of fat that was mixed with meat. In the samples with low-oxidised fat, higher protective effect was found for rosemary extract (7-11%). In the samples with high-oxidised fat, casein hydrolysate was superior to rosemary extract (14%). CONCLUSIONS: In order to increase the stability of thiamine in pasteurized or sterilized meat products with fats, the influence of fat type and its oxidative stability should be taken under consideration. Moreover, the addition of rosemary extract or casein hydrolysate has impact on the thiamine losses since it slows down lipid oxidation to a significant extent.

The effect of iodine salts on lipid oxidation and changes in nutritive value of protein in stored processed meats.

The aim was to assess the effect of iodine salts (KI or KIO(3)) on lipid oxidation as well as changes in the availability of lysine and methionine and protein digestibility in frozen-stored processed meats. Three types of iodine salt carriers were used: table salt, wheat fiber and soy protein isolate. The results showed no catalytic effect of iodine salts on lipid oxidation in stored processed meats. The application of a protein isolate and wheat fiber resulted in the inhibition of lipid oxidation in meatballs. During storage of meat products the contents of available lysine and methionine as well as protein digestibility were decreased. The utilization of wheat fiber as an iodine salt carrier had a significant effect on the reduction of lysine losses. No protective properties were found for the wheat fiber or soy protein isolate towards methionine.

Antioxidant properties of extracts from buckwheat by-products.

BACKGROUND: In the course of production of buckwheat groats by-products are produced, such as bran and hull, which apart from high content of dietary fiber, may also constitute valuable sources of antioxidants. The aim of these investigations was to determine the antioxidant activity of extracts from by-products produced during processing of buckwheat for groats. MATERIAL AND METHOD: Analyses were conducted on bran and hull of buckwheat cv. Kora. Extraction was run using acetone, methanol and water at room temperature for 24 h. The level of phenolics was determined spectrophotometrically with the Folin-Ciocalteau reagent, using (+) catechin as a standard. Antioxidant activity of extracts was analysed in relation to linoleic acid, running incubation for 19 h, by scavenging of stable radicals of DPPH (2,2-diphenyl-1-picrylhydrazyl) and on the basis of metal chelating ability. Recorded results were compared with the activity of BHT (butylated hydroxytoluene). RESULTS: The highest content of polyphenols was found in the methanol extract of hull (168.5 mg/g d.m.), which was also characterised by the best antiradical properties. The lowest content of total phenols was found for water extracts of bran after grinding and final bran, at 20.3 mg/g d.m. and 10.2 mg/g d.m. In the emulsion system the highest activity was found for methanol extracts of hull and bran after grinding (Wo = 0.89), as well as the extract of final bran (Wo = 0.85). A higher chelating ability in relation to Fe (II) ions was observed for bran extracts (after grinding - 76.1%, final bran - 62.2%) than for hull extracts (26%). CONCLUSIONS: Extracts obtained from by-products of buckwheat were characterised by high antioxidant activity in the applied model systems.