Effect of germination on total phenolic compounds,total antioxidant capacity,Maillard reaction products and oxidative stress markers in canihua (Chenopodium pallidicaule)

Germination of cereals/pseudo-cereals has been suggested as an effective method to increase antioxidant compounds. However, this process could also lead to high reducing sugar levels and subsequent Maillard reaction products. The aim of this work was to determine the time course effect of canihua (Chenopodium pallidicaule) germination on: 1) antioxidant capacity, 2) extractable and non-extractable phenolic compounds content, 3) Maillard reaction products and 4) oxidative stress markers. Germination increased antioxidant capacity, phenolic compounds and Maillard reaction products, including advanced glycated end products while it decreased oxidative stress markers. All parameters exhibited a similar time course pattern with a maximum at 72 h. In addition to the increase in phenolic compounds and antioxidant capacity, canihua germination produced advanced glycated end products. The impact on human health of these compounds in germinated seeds deserves future attention.     

Effect of bread making on formation of Maillard reaction products contributing to the overall antioxidant activity of rye bread

This paper reports the effects of flour extraction rate on antioxidant activity, early, fluorescent and coloured Maillard reaction products in rye flour, crumb, crust and bread. Extent of the reaction was determined by analyses of furosine, fluorescence compounds and browning while antioxidant properties were measured by Folin reaction, Trolox Equivalent Antioxidant Capacity (TEAC) and Oxygen Radical Antioxidant Capacity (ORAC_FL) assays. Antioxidants present in rye flours and breads scavenged peroxyl and ABTS radicals and reduced Folin-Ciocalteu reagent. Data indicated that baking favoured the formation of antioxidant compounds. In controversy, milling to obtain white rye flour negatively affected bread quality.     

Changes in the phenolic compound content and antioxidant activity in developmental maize kernels and expression profiles of phenolic biosynthesis-related genes

Phenolic compounds have various nutritional and functional properties, especially antioxidant activity. The objective of this study was to explore the relationship between the phenolic compound accumulation, antioxidant property and gene expression during maize kernel development. In this study, we explored the effects of developmental stage on the accumulation of phenolic compounds and their antioxidant activities. The expression levels of genes involved in phenolic biosynthesis were also studied. The results showed that the total phenolic content (TPC) and total anthocyanin content (TAC) were gradually increased from 15 to 48 days after pollination (DAP), whereas the total flavonoid content (TFC) decreased continuously. The antioxidant activity of maize kernels was increased gradually and positively associated with TPC. ZmCHSs in flavonoid biosynthetic pathway played important roles for total flavonoid accumulation at both early and later development stages. The expression pattern of ZmANS corresponded to the accumulation of total anthocyanin during kernel development. These results revealed that developmental stage affected the accumulation of different phenolic compounds, antioxidant activity and related gene expression. The antioxidant activity of maize kernels was dependent on the total phenolic accumulation which was related to the expression profiles of the genes participated in phenolic synthesis.     

Effect of nixtamalization process on the content and composition of phenolic compounds and antioxidant activity of two sorghums varieties

Sorghum, a competitive crop due to its agronomical advantages, has gained interest as functional food. Sorghum contains phytochemicals with health benefits and presents some antinutritional compounds such as condensed tannins (CTs). However, it is well known that CTs exhibit antioxidant capacity. This study evaluated the effect of Mexican nixtamalization on total phenols, CTs and antioxidant capacity using two varieties of sorghum. Different conditions of lime (0, 1 and 2%) and cooking time (20, 30 and 40 min) were tested to obtain the best treatment after optimization using multiple linear regression analysis, aiming to minimize the CTs content and maximize the antioxidant capacity. CTs were reduced at 27% in white sorghum and 90%, in red sorghum. Total phenols, flavonoids and antioxidant capacity had an inverse correlation with lime concentration and cooking time. The best conditions for preserving antioxidant capacity with low content of tannins were 1.13% of lime and 31.11 min cooking. The phenolic profile obtained by HPLC showed reductions in gallic and chlorogenic acids only in white sorghum, whereas catechin and quercetin decreased in both varieties. We concluded that nixtamalization effectively reduced CTs to safety intake values, allowing to preserve other phenolic compounds and antioxidant capacity.     

Direct measurement of the total antioxidant capacity of cereal products

A simple and rapid procedure was developed for the direct measurement of the antioxidant capacity of cereals. It entails grinding of cereals, mixing with 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) reagent, centrifugation and measure of the absorbance. The ABTS reagent was dissolved in a mixture of ethanol:water (50:50, v/v), instead of 100% ethanol, in order to overcome low solubility of water-soluble antioxidant compounds of some cereals. A reaction time of 30 min allowed plateau values to be reached during the antioxidant capacity measurement of cereal samples. The accuracy of the direct procedure was confirmed by measuring, in solid state, the antioxidant activity of pure phenolic compounds.The direct procedure gave results of total antioxidant capacities significantly higher than those determined by the traditional procedure (multiple extraction followed by alkaline hydrolysis) for most whole meal cereals, suggesting that such a procedure was not always sufficient to properly assess the antioxidant capacity of bound phenolic compounds in cereals. The proposed extraction-independent procedure for measuring antioxidant capacity of cereals will facilitate the inter-laboratory data comparison, the construction of reliable antioxidant capacity database and the screening of large sampling of cereals for their nutraceutical characteristics.     

Effect of baking on free and bound phenolic acids in wholegrain bakery products

Phenolic compounds, particularly ferulic acid the most abundant phenolic in wheat, are the major contributors to the in vitro antioxidant capacity. They are present in wheat in free and bound forms which affect their bioavailability. Thus the current study aims to investigate changes in free and bound phenolic acids occurred during baking in wholegrain bread, cookie and muffin. The products were also fortified with lutein due to its proved health benefits, and were previously evaluated with regard to lutein stability and bioavailability and antioxidant properties. The control and fortified wholegrain bakery products contained reasonable amounts of free and bound phenolic acids with bread products exhibiting the highest level per serving (0.6 and 11.7 mg, respectively). Ferulic acid was the principal phenolic both in the free or bound extracts of the three products followed by p-coumaric acid in the bound extracts. Baking resulted in an increase in free phenolic acids in the three products, while bound phenolic acids decreased in bread and slightly changed in cookie and muffin products. Though the effect of baking appeared to be dependent on type of baked product, type of phenolic, recipe and baking conditions, the wholegrain products should be considered good sources of phenolic antioxidants.     

Functional study of raw and cooked blue maize flour: Starch digestibility,total phenolic content and antioxidant activity

The purpose of this study was to determine the chemical composition and antioxidant capacity of blue maize (BM) (Zea mays L.) flour and to investigate the effects of polyphenol-containing extracts and BM wholegrain flour on starch digestion under uncooked and cooked conditions; commercial white maize flour was used as control. Total phenolic content in BM flour (BMF) (164 ± 14 mg gallic acid/g of dry matter) was higher than white maize (127 ± 7 mg gallic acid/g of dry matter), and the presence of anthocyanins (2.0 ± 0.5 mg cyanidin 3-glucoside/100 g) was detected. Also, an important scavenging activity against ABTS (2,2’-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid) and DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals and ferric reducing power (FRAP) was determined. Extracts of BMF reduced amylase activity (>90% of inhibition). BMF showed higher slowly digestible and resistant starch contents, thus exhibiting lower predicted glycemic index than white maize. Total anthocyanins (r = −0.89 and r = −0.79, p<0.05), antioxidant capacity (r = −0.86 and r = −0.96, p<0.05), total starch (r = 0.99 and 0.92, p<0.05) and resistant starch content (r = −0.99 and r = −0.92, p<0.05) were correlated with pGI for uncooked and cooked flours, respectively. These results indicate the potential use of BMF and its phenolic-rich extract as functional ingredients to develop antioxidant and indigestible carbohydrate-rich foods with potential health benefits.     

Quantities of phenolic compounds and their impacts on the perceived flavour attributes of rye grain

The use of whole grain rye products, beneficial to one's health, could be substantially extended if the typical intensively bitter flavour of rye could be modified without losing the characteristic rye-like flavour. The aim of the study was to evaluate the contribution of non-volatile phenolic compounds on the perceived flavour. Rye grain was milled into five milling fractions. The levels of phenolic compounds, i.e. the phenolic acids, alkylresorcinols and lignans, of the fractions were analysed and related statistically to sensory flavour profiles by partial least-squares (PLS) regression. The non-bound (free) phenolic acids are suggested to be most flavour-active. Cereal and intense flavour and aftertaste were related to vanillic and veratric acids, alkylresorcinol C_23:0, and other lignans except for pinoresinol. The perceived bitterness of the bran fractions was suggested to result from pinoresinol and syringic acid. Sinapic and ferulic acids, alkylresorcinols, except for alkylresorcinol C_23:0, and syringaresinol seemed to cause the germ-like flavour. Phenolic acids, alkylresorcinols and lignans distributed with a similar pattern in the rye grain as the flavour attributes: the phenolic compounds were clearly located in the outer bran fractions being intense in flavour, but not in the mild-tasting inner layers of the grain.     

葡萄糖-赖氨酸美拉德产物分级组分对香蕉酶促褐变的抑制

酶促褐变是香蕉加工中拟解决的关键问题,非硫安全高效抑制剂的筛选是目前的研究热点。美拉德产物（Maillard reaction products,简称MRPs）展示了其良好的抑制酶促褐变的能力,然而美拉德产物分级组分的相关研究尚未见报道。通过透析处理得到大于和小于3 500 u的分级组分,比较其抑制香蕉酶促褐变的相关能力,并对抑制机理进行研究。结果显示：3种MRPs中,MW>3 500 u的MRPs具有较好的还原力,MW<3 500 u的MRPs具有较好的DPPH·清除率、螯合铜离子能力以及抑制多酚氧化酶酶活的能力。MW<3 500 u的MRPs对游离酶抑制常数（KI）和对酶-底物络合物的抑制常数（KIS）分别为0.198 mmol/L和1.508 mmol/L,抑制类型属于混合型抑制。     

Distributions of phenolic compounds,yellow pigments and oxidative enzymes in wheat grains and their relation to antioxidant capacity of bran and debranned flour

In this study, the distribution of phenolic compounds and yellow pigments in wheat grains and their relation to the total antioxidant capacity of bran and debranned flour was investigated. Yellow pigments, the activity of lipoxygenase (LOX) and peroxidase (POX) enzymes were also determined. The bran fraction was found to contain significantly higher concentrations of phenolic acids, flavonoids and yellow pigments. The LOX activity was concentrated in endosperm and embryo, while the POX activity mostly concentrated in the bran fraction. The results suggest that the bran fraction of wheat would potentially provide naturally occurring antioxidants. From the health benefit point of view, a small level of bran incorporation to bread can be recommended to increase dietary fibre and phytonutrients in the diet.     

Effect of processing on the phenolic contents,antioxidant activity and volatile compounds of sorghum grain tea

Sorghum grain is rich in phenolic compounds and may be used to develop functional tea beverages. This work investigated the effect of processing techniques on the phenolic contents, antioxidant activity, and volatile compounds of a white colour sorghum (Liberty) grain tea. Significant (P ≤ 0.05) increase of total phenolic content, total flavonoid content and condensed tannin content were observed during the processing, whereas the antioxidant activity was not statistically enhanced. A total of 63 volatile compounds were detected including 5 alcohols, 13 alkanes, 2 aldehydes, 2 carboxylic acids, 15 esters, 4 ketones, 3 pyrazines and 1 phenylenediamine, which were affected by the processing techniques. The sorghum tea made from powder form infusion had more abundant volatile compounds compared to whole grain form infusion. The findings of this research have potential to expand human consumption of sorghum grain in the new form of grain tea.     

Determination of In Vitro Antidiabetic Effects, Antioxidant Activities and Phenol Contents of Some Herbal Teas

In this research, some herbal teas and infusions traditionally used in the treatment of diabetes in Turkey, have been studied for their antidiabetic effects on in vitro glucose diffusion and phenolic contents and antioxidant activities. Ten aqueous herbal tea extracts were examined using an in vitro method to determine their effects on glucose movement across the gastrointestinal tract. Total phenol content of herbal teas was analyzed by Folin–Ciocalteu’s procedure. Antioxidant activities of herbal teas were evaluated by the effect of extracts on DPPH radical and hydrogen peroxide scavenging. Antioxidant activity was defined as the amount of the sample to decrease the initial DPPH· concentration by 50% as efficient concentration, EC₅₀. Antiradical activity [AE] was calculated as 1/EC₅₀. Values were evaluated statistically. Results support the view that none of the herbal teas showed antidiabetic effect on glucose diffusion using in vitro model glucose absorption. Teas were arranged in the order of green tea > peppermint > thyme > black tea > relax tea > absinthium > shrubby blackberry > sage > roselle > olive leaves according to their total phenol contents. Among ten herbal teas, green tea had the highest hydrogen-donating capacity against to DPPH radical. Ranking of the herbal teas with respect to their DPPH radical scavenging activity were green tea > peppermint > black tea > thyme > relax tea > absinthium > roselle > olive leaves > sage > shrubby blackberry. It was determined that adding flavoring substances such as lemon, bergamot, clove and cinnamon, which are commonly used in preparation of black tea in Turkey resulted to have synergistic effect on total antioxidant activities of black and peppermint teas. The highest hydrogen peroxide inhibition value (65.50%) was obtained for green tea at a 250 μl/ml concentration. The H₂O₂ scavenging activity of herbal teas decreased in the order green tea > peppermint > relax tea > black tea > thyme > olive leaves > sage > absinthium > shrubby blackberry > roselle. In particular, their phenolic compounds and antioxidant activities may be useful for meal planning in type 2 diabetes. They could contribute to sustain plasma antioxidant level because antioxidants present in plants and herbs prevent the development of vascular diseases seen in type 2 diabetes.     

Effect of flaxseed flour on rheological properties,staling and total phenol of Iranian toast

Effect of adding flaxseed flour (10%, 20% and 30% w/w) to wheat flour on rheological properties of dough, including water absorption, stability and development time, extensibility and resistance to extension, was studied at 45, 90 and 135 min proving time. Qualitative properties of toast regarding staling (after 24 and 72 h) were determined. Phenolic compounds, peroxide values, sensory characteristics and color indices of the breads were evaluated. The results indicated that water absorption and development time increased as the proportion of flaxseed increased in dough. Stability decreased with the increment of flax flour compared to control sample (100% wheat flour). Extensibility and resistance to extension of flaxseed samples respectively decreased and increased comparing to those of control sample. Staling in toast with 20% flaxseed flour was seen to be lower than that of the control. Adding flax flour caused phenolic compounds to increase, however it decreased peroxide value. Bread color parameters L and a reduced by adding flax flour, while parameter b did not show significant different compared to the control (p < 0.05). Results of sensory evaluation indicated that brightness of the toasts decreased with increasing flaxseed flour and that 30% flaxseed toast had the lowest score for overall acceptability.     

Antioxidant activity and phenolic composition of the medicinal and edible halophyte Mesembryanthemum edule L.

Mesembryanthemum edule L. (sourfig, Aizoaceae) has long been used as food and in traditional medicine. This study was intended to characterize the antioxidant properties and the phenolic compounds of M. edule leaf, stem and root. The approach consisted to evaluate these organs for their antioxidant activities through several in vitro tests, to determine tissue contents in total phenolics, flavonoids and proanthocyanidins and to establish the phenolic composition through RP-HPLC analysis. All studied organs showed a high antioxidant activity as compared to positive control BHT, with maximal efficiency for stems followed by leaves and roots. The highest polyphenolic levels were found in stems and leaves (86.5 and 68.7 mg GAE g⁻¹ DW, respectively), suggesting that their strong antioxidant activity could be attributed to these phytochemicals. The HPLC analysis revealed that the main phenolic compounds were quercitrin and avicularin (1.4 and 1.15 mg g⁻¹ DW, respectively) in the leaves, while catechin and procyanidin B2 (1.66 and 1.54 mg g⁻¹ DW, respectively) were the most abundant phenolics in the stems. Overall, the strong antioxidant activity and richness of M. edule aerial tissues suggest that it could be advantageously used as a functional or nutraceutical food, to prevent or moderate oxidative stress-related diseases.     

光照对黑青稞萌发过程中褪黑素、酚类物质含量和抗氧化活性的影响

为研究光照对青稞萌发过程中功能成分的影响,以隆子黑青稞为材料,采用酶联免疫吸附法和分光光度计法测定了不同光照时间处理下黑青稞萌发过程中褪黑素、总酚和总黄酮含量及其抗氧化活性;同时测定了黑青稞发芽率、胚根和胚芽长度,并对避光萌发5 d的芽苗进行了感官评定.结果表明,随萌发时间的延长,青稞芽苗中褪黑素、总酚和总黄酮含量与种...     

DEHP对玉米苗期光合特性及抗氧化能力的影响

以玉米品种郑单958为试验材料,设置空白对照组(CK)及C1(50 mg/kg)、C2(100 mg/kg)、C3(150 mg/kg)3种不同浓度的DEHP(邻苯二甲酸二乙基己酯)处理玉米幼苗,对幼苗的生长情况、叶绿素含量、光合特性以及抗氧化酶活性等多个指标进行测定。结果表明,随着DEHP浓度的升高,玉米幼苗生长发育的抑制作用越明显,叶片中叶绿素含量、净光合速率(P_n)、蒸腾速率(T_r)显著降低,胞间二氧化碳浓度(C_i)显著升高,PSⅡ最大光化学效率(F_v/F_m)与光合性能指数(PI_ABS)均呈下降趋势,1,5-二磷酸核酮糖羧化酶(Ru BP羧化酶)活性与磷酸烯醇式丙酮酸羧化酶(PEP羧化酶)活性均显著降低,超氧化物歧化酶(SOD)活性显著上升,抗坏血酸过氧化物酶(APX)活性显著下降,过氧化物酶(POD)活性呈先上升后下降的趋势,在DEHP浓度为50 mg/kg时达最大值。     

Effects of formulation and extrusion cooking conditions on furfural and hydroxymethylfurfural content

The objective of this research was to investigate the effects of different ingredients (reducing sugars, leavening agents, citric acid), processing conditions (feed moisture content, exit die temperature), and extrusion cooking methods (with/without CO₂ injection) on furfural and 5-hydroxymethylfurfural (HMF) formation in corn-based extrudates. The decrease in furfural levels was 16% upon addition of sodium-bicarbonate, while the increase was 12% upon addition of ammonium-bicarbonate for extrudates produced at 150 °C and feed moisture content of 22%. The furfural concentration of extrudates produced at 150 °C and feed moisture content of 22% without leavening agents was 810 μg/100 g and increased to 11,901 μg/100 g upon citric acid addition (about a 15-fold increase). Furthermore, both low feed moisture and high exit die temperature had promoting effects on furfural and HMF contents. The CO₂ injection method did not have considerable effect on furfural and HMF levels of the extrudates; however, it positively affected the physical properties of extrudates.     

Phenolic compounds in raw and cooked rice (Oryza sativa L.) and their inhibitory effect on the activity of angiotensin I-converting enzyme

Whole rice has been widely studied due to the abundance of bioactive compounds in its pericarp. Some of the beneficial effects of these compounds on human health have been attributed to their antioxidant and other biological activities, such as enzyme inhibition. In this work, we evaluated the contents of total, soluble and insoluble phenolic compounds of 6 red and 10 non-pigmented genotypes of whole rice as well as their inhibitory effect on the activity of angiotensin I-converting enzyme (ACE). The effects of cooking on phenolics and their inhibitory activities were also investigated. Red genotypes showed high content of phenolics, mainly soluble compounds, at an average of 409.7 mg ferulic acid eq./100 g, whereas overall lower average levels (99.4 mg ferulic acid eq./100 g) at an approximate soluble/insoluble compound ratio of 1:1 were observed in non-pigmented rice. Pigmented rice displayed a greater inhibitory effect on ACE than non-pigmented rice. In fact, a significant correlation between the content of soluble phenolics and ACE inhibition was observed (r = 0.8985, p < 0.05). In addition to significantly reducing the levels of total phenolics and ACE inhibition, cooking altered the soluble/insoluble compound ratio, especially among red rice genotypes.     

磷对盐胁迫下玉米幼苗脂质过氧化特性及抗氧化酶活性的影响

采用水培试验,研究不同浓度磷对盐胁迫下玉米幼苗生长、叶片和根系中脂质过氧化特性及其抗氧化酶活性的变化.研究表明,盐胁迫下,增施磷可明显缓解盐胁迫对玉米幼苗生长的抑制,各器官含水量增加,改善植株体内的水分代谢状况.随磷含量增加,玉米幼苗叶片细胞膜透性逐渐降低,叶绿素含量增加,叶片和根系中SOD、CAT和POD活性明显增加...     

苯肽胺酸对低温胁迫下玉米幼苗抗氧化系统和氮代谢的影响

以玉米品种郑单958为试材,设常温下喷施清水（CK）、常温下喷施苯肽胺酸（PA）、低温下喷施清水（LT）和低温下喷施苯肽胺酸（LT+PA）4个不同处理,低温处理7 d后将玉米幼苗移入常温环境下恢复3 d,测定各处理幼苗生长情况、细胞质膜透性、活性氧（ROS）、抗氧化酶活性和氮代谢相关指标。结果表明,低温胁迫下,幼苗叶片活性氧和丙二醛（MDA）含量显著增加,膜透性增大,胁迫前期会诱导酶促抗氧化防御系统活性增强,随胁迫时间延长,抗氧化酶活性均呈下降趋势;氮素吸收量逐步减少,氮代谢相关酶活性呈明显降低趋势,玉米幼苗生长受到严重抑制。叶面喷施苯肽胺酸可显著减少膜损伤来促进根系对NO₃^-的吸收和提高抗氧化酶活性,同时氮代谢关键酶活性的上升和GS/GOGAT代谢途径的正常运行在氮代谢中发挥积极作用。