Folate Content and Yolk Color of Hen Eggs from Different Farming Systems.

This study aimed to compare folate contents in hen eggs from four different farming systems, namely organic, free range, barn, and cage one. Folate retention during egg boiling was studied as well. The contents of individual folate vitamers were determined using the high-performance liquid chromatography method (HPLC), following trienzyme treatment. Folate content in eggs differed significantly (p < 0.05) due to the rearing system, with the highest mean content determined in the eggs from organic farming (113.8 µg/100 g). According to this study, one egg (60 g) may provide 40-86 µg of folates, which corresponds to 10-22% of the recommended daily intake for adults, 400 µg according to the Nutrition Standards for the Polish Population. The predominant folate form found in egg was 5-methyltetrahydrofolate, which showed considerably greater stability under boiling compared to 10-formylfolic acid present in a lower amount. In most eggs tested, the losses in total folate content did not exceed 15%. The color of yolk of the most folate-abundant organic eggs, had the highest value of lightness (L*) and the lowest value of redness (a*). This, however, does not correspond to consumer preferences of intense golden yolk color.

Effect of Microwave Heating on the Acrylamide Formation in Foods.

Acrylamide (AA) is a neurotoxic and carcinogenic substance that has recently been discovered in food. One of the factors affecting its formation is the heat treatment method. This review discusses the microwave heating as one of the methods of thermal food processing and the influence of microwave radiation on the acrylamide formation in food. In addition, conventional and microwave heating were compared, especially the way they affect the AA formation in food. Available studies demonstrate differences in the mechanisms of microwave and conventional heating. These differences may be beneficial or detrimental depending on different processes. The published studies showed that microwave heating at a high power level can cause greater AA formation in products than conventional food heat treatment. The higher content of acrylamide in microwave-heated foods may be due to differences in its formation during microwave heating and conventional methods. At the same time, short exposure to microwaves (during blanching and thawing) at low power may even limit the formation of acrylamide during the final heat treatment. Considering the possible harmful effects of microwave heating on food quality (e.g., intensive formation of acrylamide), further research in this direction should be carried out.

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 Content of Dietary Fibre and Polyphenols in Morphological Parts of Buckwheat (Fagopyrum tataricum).

In this report, we presented the profile of polyphenolic substances in flowers, leaves, stalk and roots of Fagopyrum tataricum estimated by using RP-UHPLC-ESI-MS equipment (reversed-phase ultra-high-performance liquid chromatography electrospray ionisation mass spectrometry). The neutral detergent fibre, acid detergent fibre, acid detergent lignin, cellulose and hemicellulose were also determined. Flowers, leaves, stalk and roots showed varying levels of dietary fibre and polyphenols. The highest content of neutral and acid detergent fibre were found in the roots (63.92 and 45.45% d.m., respectively) while the most rich in phenolic compounds were flowers (4.8 mg/1 g d.m.). Root and stalk contained the highest level of cellulose, 38.70 and 25.57% d.m., respectively. Among the investigated polyphenolic substances such as: 2,6-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 4-hydrobenzoic acid, caffeic acid, catechin, chlorogenic acid, fagopyrin, ferulic acid, myricetin, gallic acid, isovanilic acid, isovitexin, kaempferol, luteolin, p-coumaric acid, procyanidin B2, quercetin, quercetin 3-D galactoside, rutin, syringic acid and vitexin, we observed that the contents of rutin and chlorogenic acid were the highest. We found some correlation between dietary fibre fractions and individual phenolic substances. The levels of acid detergent fibre (ADF), cellulose and hemicellulose were negatively correlated with isovitexin, kaempferol, vitexin, fagopyrin, caffeic acid and procyanidin B2 content. In this investigation, two solvents (water and methanol) were estimated regarding their extraction efficiency of phenolic compounds. Taking these results into consideration, we recommend using methanol as the extractor to isolate chlorogenic acid, fagopyrin, kaempferol, procyanidin B2, quercetin, quercetin 3-D-galactoside, rutin, vitexin, and water for other investigated polyphenolic substances obtained from Fagopyrum tataricum.

Effect of Storage on Acrylamide and 5-hydroxymethylfurfural Contents in Selected Processed Plant Products with Long Shelf-life.

This study investigated the effects of storage and temperature duration on the stability of acrylamide (AA) and 5-hydroxymethylfurfural (HMF) in selected foods with long shelf-life. Products were analysed fresh and stored at temperatures of 4 and 25 °C after 6 and 12 months (with the exception of soft bread samples, which were analysed after 15 and 30 days). The AA and HMF contents were determined with RP-HPLC coupled to a diode array detector (DAD). AA and HMF were not stable in many processed plant products with a long shelf-life. The highest AA reduction and the largest increase in HMF content were observed in the samples stored at a higher temperature (25 °C) for 12 months. It was found that an initial water activity of 0.4 is favourable to HMF formation and that AA reduction may be considerably greater in stored products with a low initial water activity. The kind of product and its composition may also have a significant impact on acrylamide content in stored food. In the final period of storage at 25 °C, acrylamide content in 100% cocoa powder, instant baby foods, 20% cocoa powder and instant coffee was 51, 39, 35 and 33% lower than in products before storage, respectively. It was observed that a large quantity of ε-NH2 and SH groups of amino acids in some products can be assumed as the reason for the significant AA degradation.

Effect of Wheat Dietary Fiber Particle Size during Digestion In Vitro on Bile Acid, Faecal Bacteria and Short-Chain Fatty Acid Content.

The influence of bile acid concentration on the growth of Bifidobacterium spp. and Lactobacillus spp. bacteria was demonstrated. Exposing these bacteria to the environment containing bile acid salts, and very poor in nutrients, leads to the disappearance of these microorganisms due to the toxic effect of bile acids. A multidimensional analysis of data in the form of principal component analysis indicated that lactic acid bacteria bind bile acids and show antagonistic effect on E. coli spp. bacteria. The growth in E. coli spp. population was accompanied by a decline in the population of Bifidobacterium spp. and Lactobacillus spp. with a simultaneous reduction in the concentration of bile acids. This is direct proof of acid binding ability of the tested lactic acid bacteria with respect to cholic acid, lithocholic acid and deoxycholic acid. This research demonstrated that the degree of fineness of wheat dietary fibre does not affect the sorption of bile acids and growth of some bacteria species; however, it has an impact on the profile of synthesized short-chained fatty acids. During the digestion of a very fine wheat fibre fraction (WF 90), an increase in the concentration of propionic and butyric acids, as compared with the wheat fiber fraction of larger particles - WF 500, was observed. Our study suggested that wheat fibre did not affect faecal bacteria growth, however, we observed binding of bile acids by Bifidobacterium spp. and Lactobacillus spp.

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 freezing technology and storage conditions on folate content in selected vegetables.

Folates (B vitamins) are essential for the proper function of many bodily processes. Although a rich natural source are vegetables, the literature lacks data on the effect of the pre-treatment and freezing technologies used in vegetable processing and frozen storage time on the folate content in these materials. Moreover, since folates are very unstable nutrients, the amount available in processed and stored foods can be significantly lower than in raw products. In tested vegetables (green beans, yellow beans, peas, cauliflower, broccoli and spinach), one folate form was identified, 5-methyltetrahydrofolate (5-CH3-H4folate). It was observed that pre-treatment and freezing technology significantly (p < 0.05) decreased 5-CH3-H4folate content only in vegetables with the largest degree of fragmentation (cut and briquetted spinach) and the smallest size (peas). In all analyzed samples, the 5-CH3-H4folate content decreased with the time of frozen storage. In frozen cauliflower, the 5-CH3-H4folate loss exceeded 95 % compared to the fresh product just after the third month of frozen storage. Meanwhile, in green and yellow beans, significant 5-CH3-H4folate losses (at the level of 75 % and 95 %, respectively) were observed no earlier than after the 9th month of frozen storage.

Phenolic compounds as cultivar- and variety-distinguishing factors in some plant products.

The aim of the study was to determine whether phenolic compounds in some varieties of buckwheat, winter and spring barley and peas can be used as factors which distinguish selected cultivars and varieties of plant material. It was observed that the content of total phenolics might be useful as a cultivar-distinguishing factor for all the plant materials analyzed, but it was a distinguishing factor for only some varieties. Individual cultivars and varieties were best distinguished by the content of syringic acid. The levels of syringic and vanillic acids were in reverse proportion to the total amount of phenolics soluble in methanol and a positive correlation between syringic and ferulic acid was observed. Moreover, the protein content of plant material was analyzed and a significant (p ≤ 0.05) correlation between this component and ferulic and vanillic acids was noted.

The effect of domestic preparation of some potato products on acrylamide content.

The influence that food heating has on the concentration of acrylamide in home-cooked potato dishes prepared by high-temperature, such as pan-frying, deep-frying, roasting and microwave heating was analyzed. The experiment was performed with commercially available deep-frozen par-fried French fries and deep-frozen par-fried potato products other than French fries (cubes, wedges, noisettes, pancakes). Acrylamide was found in all deep-frozen par-fried French fries and other deep-frozen par-fried potato products before domestic preparation. The mean level of acrylamide content in all frozen potato products before preparation was found to be 322 µg/kg. Potato products were then prepared at 180 °C for 3 min and at 220 °C for 10 min. After domestic preparation (roasting, pan-frying, deep-frying and microwave heating) it was found that the level of acrylamide in all products increased. Acrylamide content in the analyzed samples significantly increased as the temperature and time of processing increased. The statistical analysis showed significant differences (P < 0.05) for acrylamide content as a function of food preparation. The level of acrylamide increased with the increased heating temperature and heating time. Additionally, the preparation method of roasting was significantly lower in acrylamide content (P < 0.05) than the preparation method of microwaving although both preparation methods used the same conditions (time and temperature). These results suggest that microwaving might be more favourable to the formation of acrylamide than conventional heating methods, such as roasting.

Bioactive Compounds in Different Buckwheat Species.

The accumulation of valuable nutrients in cereal grains depends on a number of factors, including species, cultivars, and environment conditions. The aim of this study was to compare protein, some polyphenols and rutin content, as well as mineral composition in Fagopyrum tataricum and Fagopyrum esculentum genotypes growing in Polish conditions. A field experiment was conducted on pseudopodsolic soil in 2017-2018 at the Experimental Station in Osiny (51°35', 21°55'), following randomized complete block method with three replications. Two cultivars of Fagophyrum esculentum (Kora and Panda), two cultivars of Fagopyrum tataricum (LIT1 and 63181) and two forms of Fagopyrum esculentum (Red Corolla and Green Corolla) were used in this experiment. We found differences in the tested compounds (protein, phenolic acids, rutin, and mineral composition) between cultivars and genotypes. Total phenolic acid and rutin contents were higher in the Fagopyrum tataricum compared to Fagopyrum esculentum. Ferulic and coumaric acids were prominent in the Kora and Panda cultivars, however vanillic and syringic acids accumulated more in Green Corolla and Red Corolla. The common buckwheat seeds contained more Cu, Mn, and Mg and less Ca than tartary buckwheat. Moreover Fagopytum esculentum genotype contains more protein compared to Fagopyrum tataricum.

Effect of Different Cooking Methods on Folate Content in Chicken Liver.

Common liver sources in European countries include cow, chicken, duck, lamb and pig. Despite its decreasing popularity, liver is possibly one of the most nutrient-dense foods, being rich in high-quality protein and low in calories. In animals, the liver is the storage organ for folate. In this study, the effect of different cooking methods on folate vitamers content in chicken liver was investigated. Three folate derivatives, 5-CH3-H4PteGlu, H4PteGlu and 5-HCO-H4PteGlu, were identified in the analyzed samples using high performance liquid chromatography (HPLC). The folate content in liver after sous-vide (60 °C/75 min) and steaming (100 °C/30 min) did not differ significantly (p ≤ 0.05) from raw liver folate content (781 µg/100 g). Even liver cooked in a combi oven or grilled (which resulted in significant folate losses) showed much higher folate content, 455-631 µg/100 g and 612-715 µg/100 g, respectively, than the most folate-abundant plant foods. These findings are important as they demonstrate that processed liver has the potential to improve the supply of folate and meet the recommended daily requirements, particularly when folate deficiency is common worldwide.

Folates stability in two types of rye breads during processing and frozen storage.

High-performance liquid chromatography was used to study the stability of folate vitamers in two types of rye breads after baking and 16 weeks of frozen storage. Bread made using sourdough seeds contained less total folate (74.6 microg/100 g dry basis, expressed as folic acid) than the whole rye flour (79.8 microg/100 g dry basis) and bread leavened only with baker's yeast (82.8 microg/100 g dry basis). Most importantly, it was generated by a significant decrease in 5-CH3-H4folate form. The baking process caused some changes in folate distribution. Storage of breads at -18 degrees C for 2 weeks did not have a significant effect (p < 0.05) on total folates compared to the content directly after baking. After a 5-weeks storage period, a significant decrease (p < 0.05) in the content of total folates was recorded and it dropped on average by 14% for both type of breads. After a longer period of storage (16 weeks), a 25% loss of folates in the bread made with baker's yeast and a 38% loss in the bread fermented with sourdough seeds was found. Retention of 5-CH3-H4folate and 10-HCO-H2folate forms were much lower in the bread made with a sourdough addition than with baker's yeast only.

Acrylamide and Thermal-Processing Indexes in Market-Purchased Food.

Determining acrylamide (AA) content in foods using chromatographic methods is expensive and time-consuming. Therefore, there is a need to develop a simple, economical method for monitoring the content of acrylamide in foods. This study analysed whether there is a relationship between acrylamide levels with some heat-induced parameters, such as 5-hydroxymethylfurfural (HMF) and browning, in order to assess their usefulness in predicting the potential acrylamide levels in market-purchased food. Sixty plant-based food products were tested. The correlation coefficients for AA levels with L*, a* and b* values and HMF content were significant (p < 0.05) for French fries and potato chips. There was no statistically significant correlation between thermal-processing indexes (HMF and colour parameters) and acrylamide levels in commercial bread, breakfast cereals and biscuits. The results indicate that these classical thermal-processing indexes are not directly related to the acrylamide content in commercial cereal-based food and they cannot be indicators of AA level. Thus, the correlation between HMF and colour parameters with acrylamide content depends on the type of food and it is difficult to estimate the amount of AA based on these classical thermal-processing indexes of market-purchased food.

Effect of baking process on added folic acid and endogenous folates stability in wheat and rye breads.

In Poland bread as a staple food both made from wheat and rye flour can be a potential product for future fortification with folic acid. The objective of the study was to examine the effect of fermentation and baking on added folic acid and some endogenous folates stability during breadmaking of rye and wheat breads. Breads were produced using the formulation containing enriched flour with 0.2 mg folic acid/100 g product, baker's yeast and additionally ascorbic acid for wheat bread and lactic acid for rye bread. Folates were extracted with Hepes/Ches buffer (pH = 7.85) followed by destruction of matrix by amylase and protease and deconjugation with rat serum conjugase. Affinity chromatography (FBP bovine milk) was used to purify and concentrate samples. The folates were separated by HPLC with C18 column and with a combination of fluorescence and UV detection. For both rye and wheat breads there was a decrease of folic acid from flour to bread stage. The total losses depend on baking process and ranged from 12 to 21%. Some changes in the level of different native folate forms during the stage of baking process were also observed.