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.     

Effects of infrared heating on phenolic compounds and Maillard reaction products in maize flour

Maize grains were heated by infrared radiation for 50–100 s, than flaked and milled. The output was set to 110, 115, 120 and 140 °C to determine the effect of temperature on the formation of acrylamide, 5-hydroxymethylfurfural (HMF) and furosine, as well as the level of phenolic compounds in maize flour and its total antioxidant capacity (TAC). Acrylamide and HMF levels were increased as the load of the heat treatment was increased in grains, while furosine concentration was rapidly increased to an apparent maximum (34.96 μg/g) followed by decrease during heating. Acrylamide, as well as HMF variables correlated very well with TAC of heat-treated flour (r² = 0.98 and 0.86). The process of infrared heating had a great influence on the reduction of phenolic compound contents. However, new antioxidants that were formed as a result of the Maillard reaction increased the total antioxidant capacity of heat-treated maize flour.     

不同类型大麦品种籽粒中酚酸类化合物含量的变异规律

为了探明不同类型大麦品种籽粒中酚酸类化合物含量的变异规律,采用超声辅助提取、高效液相色谱法测定的方法对15个大麦品种（系）籽粒中的13种酚酸进行了提取、测定和分析。结果表明,大麦籽粒中的酚酸类化合物主要是羟基苯甲酸衍生物,羟基肉桂酸衍生物含量较少。不同品种和不同类型大麦品种籽粒中酚酸类化合物的含量存在极显著的差异,黑皮大麦籽粒中总羟基苯甲酸衍生物（THBA）、总羟基肉桂酸衍生物（THCA）和总酚酸（TPA）的含量均高于非黑皮大麦;二棱大麦籽粒中THBA、THCA和TPA的含量均高于多棱大麦;皮大麦籽粒中THCA和TPA的含量高于裸大麦,但THBA的含量与裸大麦无显著差异。另外,与裸大麦相比,皮大麦籽粒中含有更为丰富的酚酸种类。     

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.     

Enhancing three phenolic fractions of oats (Avena sativa L.) and their antioxidant activities by solid-state fermentation with Monascus anka and Bacillus subtilis

This work aims to improve phenolic fractions of oats and their antioxidant activities by solid-state fermentation (SSF) combining Monascus anka with Bacillus subtilis. Results revealed that the fermentation system significantly (p < 0.05) increased the total phenolic content (TPC), which was 23-fold over that in unfermented oats. The hydrolytic enzyme activities of α-amylase, β-glucosidase, and cellulase were significantly (r > 0.75, p < 0.05) correlated to the TPC, indicated an important role in the release of phenolic in oats. The proportion of free phenolic fraction in oats was increased from 39.76% to 61.62%, while that of bound phenolic fraction decreased from 42.17% to 22.78%. Moreover, the phenolic compositions of free, conjugated and bound phenolic fractions varied with fermentation. It implied that the phenolic compounds in different forms could be converted and transformed in the SSF system. Meanwhile, the DPPH· and ABTS^·+ scavenging activities of the free and conjugated phenolic fractions in oats became stronger after fermentation. It indicated that the changes of antioxidant activities of phenolic fractions might be closely related to the structural modification by microbial enzymes in the SSF system. Consequently, this study provides a prospect fermentation process for improving the phenolic release and antioxidant activities in oats.     

Enzyme inhibitory and antioxidant activity of Melia azedarach L. naturalized in Anatolia and its phenolic acid and fatty acid composition

In the present study, acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and tyrosinase inhibitory and antioxidant activities of the fruit and leaf extracts of Melia azedarach L. (Meliaceae) of Turkish origin were evaluated. Enzyme inhibitory activity of the extracts was tested in vitro using ELISA microplate reader. Antioxidant activity of the extracts was tested using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, ferrous ion-chelation, and ferric-reducing antioxidant power (FRAP) assays. Phenolic composition of the extracts was elucidated by high performance liquid chromatography (HPLC) and fatty acid compositions of the fatty oils of the fruits and leaves were elucidated by gas chromatography-mass spectrometry (GC-MS). The ethyl acetate extract from the leaves showed the highest inhibition against AChE (33.63 ± 1.40%) and BChE (92.89 ± 3.05%). The methanol extract from the leaves exerted the best antioxidant activity in DPPH radical scavenging and FRAP assays, while the ethyl acetate extracts of the fruits and leaves had the most notable effect in metal-chelation assay.     

Influence of sprouting and elicitation on phenolic acids profile and antioxidant activity of wheat seedlings

Influence of germination and elicitation on nutraceutical potential of sprouted wheat was investigated. The seeds of three Polish winter wheat cultivars were elicited with 0.1% (w/v) of Saccacharomyces cerevisiae (SC) extract, 0.1% (v/v) Salix daphnoides (SD) bark extract and their combinations (SC/SD 1:1). Seeds were germinated for 4 day at 20 °C in darkness. For phenolic acids determination LC-ESI-MS/MS analysis was used. Antiradical ability, chelating power, reducing power and ability to prevent lipids against oxidation were determined. Bioaccessibility of antioxidative compounds was estimated using in vitro digestion method. Eleven phenolic acids (protocatechuic, p-hydroxybenzoic, vanillic, caffeic, syryngic, p-coumaric, cis- and trans-ferulic, salicylic, trans- and cis-synapinic) were identified. Sprouting increased p-hydroxybenzoic, syryngic and p-coumaric acids level. The most effective elicitor for improving antioxidant activity of potentially bioaccessible phytochemicals was SD. Especially high effect was obtained for antiradical activity, chelating power and ability to lipid prevention.     

红参、红枣复合饮料的研制及其抗氧化性研究

目的 优化出红参、红枣复合饮料加工工艺,并对其抗氧化性进行研究,为人参食品的深加工利用提供技术支撑.方法 以人参、红枣为原料,以感官评价为试验指标,通过单因素试验和正交试验优化出红参、红枣复合饮料的加工工艺;并通过测定复合饮料对DPPH自由基的清除率研究其抗氧化性.结果 优化的工艺为红枣汁:红参汁比例为21:1、糖添加...     

Hydrothermal and biotechnological treatments on nutraceutical content and antioxidant activity of rice bran

The effect of processing such as steaming, germination and parboiling on nutraceuticals and in vitro bioactive properties of rice bran from three different rice varieties namely Jyothi (pigmented), IR64 and Sona masuri (non-pigmented) were investigated. Within the varieties envisaged, pigmented Jyothi variety contained higher levels of vitamin E, soluble, bound and total polyphenol, flavanoids, free radical scavenging activity and total antioxidant activity. Direct steam exposure of bran resulted in an increase in, ether extractives and oryzanol, as well as retention of all the vitamin E components, bound polyphenols, flavonoids and decrease in soluble and total polyphenol content, free radical scavenging activity and total antioxidant activity compared to native. Parboiling as well as germination of paddy resulted in an increase, in the content of ether extractives and oryzanol, whereas other bioactive properties decreased compared to native. Hence it may be concluded that bioactive components and antioxidant properties were significantly higher in Jyothi bran compared to the other two paddy brans, and processing leads to changes in bioactive properties with maximum retention of bioactive components in the steamed bran.     

High potential of agro-industrial by-products of pomegranate (Punica granatum L.) as the powerful antifungal and antioxidant substances

Microorganisms such as fungi are one of the most important factors that cause oxidative processes during postharvest stage and consequently deterioration of agriculture products would not be unexpected. On the other hand, high antioxidant properties of industrial by-products of pomegranate propose them as powerful antioxidant and antifungal substances. So to investigate the antioxidant and antifungal properties of pomegranate, two independent factorial experiments based on randomized design with 5 replications were conducted. In the first experiment the effect of 3 different parts of pomegranate (peel, seed and leaf) and 2 different kinds of extracts (aqueous and methanolic) with 4 concentrations (0, 500, 1000 and 1500 ppm) were investigated on 3 postharvest fungi (Penicillium italicum, Rhizopus stolonifer and Botrytis cinerea). In the second experiment antioxidant capacity and phenolic content were measured for two different extracts from different parts. Based on the results the methanolic extract showed the highest inhibitory effects on the mycelia growth (IMG) and spore germination (ISG) with 49.82 and 41.25% respectively. On the other hand, peel and seed extracts had more inhibitory effect (IMG and ISG) than leaf extract. The phenolic content of peel extract were also measured 2.8 fold higher than pomegranate leaf extract and antioxidant capacity of peel, seed and leaf extracts of pomegranate were 55.3%, 35.7% and 16.4% respectively. Therefore, it seems that the high percentage of phenolic content in the peel and seed of pomegranate could cause the high antifungal and antioxidant activity of their extracts.     

Individual polyphenolic profiles and antioxidant activity in sorghum grains are influenced by very low and high solar UV radiation and genotype

Sorghum is becoming more widely recognised around the world as a valuable crop for its polyphenol antioxidant health-promoting properties and adaptation to harsh environments. The antioxidant capacity of diverse polyphenols in sorghum grain can vary with climatic conditions and genotype. To explore this further, the potential role of UV radiation on the profile and concentration of polyphenols was investigated in six diverse sorghum genotypes in a controlled environment facility using natural UV and visible radiation under either UV-transmitting or UV-blocking treatments. The polyphenol content and antioxidant activity were significantly reduced under the UV-blocking treatment, with contents of individual polyphenols differing among the genotypes. This information is valuable for sorghum breeders enabling them to select genotypes and UV growth conditions to produce sorghum grain with target levels of polyphenols and antioxidant capacity for human foods to meet the nutritional and health needs of different consumers.     

Source/sink ratio and the relationship between maximum water content,maximum volume,and final dry weight of maize kernels

Final kernel weight (KW) is closely related to maximum kernel volume (KV) and maximum kernel water content (KWC). It is not clear, however, how changes in the reproductive sink capacity, assimilate availability during grain filling and physical restriction to kernel expansion affect the relationship between KW and KWC or between KW and KV. Three experiments were conducted at Balcarce, Argentina and Ames, USA. Defoliation, thinning, plant density, restricted pollination and volume restriction treatments were imposed to manipulate KV, sink and source capacity. KW varied from 111 to 436 mg across all hybrid–treatments combinations and was related to the source/sink ratio during grain filling (r² = 0.85). Treatment variation in KW was related primarily to changes in kernel growth rate, except for the complete defoliated treatment, which also shortened the duration of grain filling. KW was correlated with maximum KWC (r² = 0.77, p < 0.001) and with maximum KV (r² = 0.91, p < 0.001). The developmental patterns for KW, KWC and KV during grain filling were not affected by the source/sink manipulations, except for severe defoliation. In the latter case, maximum KWC was not a good estimate of final KW. KV, however, was sensitive to reductions in carbohydrate supply during grain filling and was closely correlated to KW. Physical restriction to kernel expansion reduced kernel weight 13% relative to its control (p < 0.01). But restricting kernel expansion did not alter the general relationships between KW and KWC or between KW and KV, because kernel density was not affected.     

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.     

玉米幼苗叶表面蜡质含量及成分对干旱胁迫的响应

选用抗旱性不同的两个玉米自交系Mo17和B73为试验材料,采用盆栽控水试验,设置干旱和正常浇水两个处理,研究干旱胁迫对两个玉米品种3叶期幼苗叶面蜡质含量及成分变化的影响。结果表明,在干旱处理条件下,Mo17和B73的叶片失水率和叶绿素的抽提率均低于正常条件;两个品种叶面的蜡质含量均明显高于正常条件下的蜡质含量,且Mo17在正常和干旱条件下蜡质含量均高于B73。此外,在干旱条件下,蜡质合成相关的基因KCS、CER1、CER2、GL1、GL2和GL15的表达也明显增高。玉米叶片表面蜡质合成是应答干旱胁迫的一种重要方式,抗旱品种Mo17的抗旱性比B73要强,其表面蜡质合成较强是其中一个重要原因。     

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.     

芝麻赤霉素合成相关基因鉴定与表达分析

赤霉素的生物合成是多种酶促反应的过程,与植物植株发育、逆境响应密切相关。为分析芝麻基因组中赤霉素合成相关基因的分布、结构和活性特征,本研究以芝麻基因组序列和不同组织转录组为对象,通过生物信息学方法,从中共鉴定出32个赤霉素合成相关基因,分属7个不同的基因家族,分布在除5号染色体外芝麻所有的染色体上。不同基因家族蛋白质肽链长度存在较大差异,其中CPS家族的蛋白质序列最长,平均包含776个氨基酸残基;KAO家族蛋白序列长度的变异最大,在401-834个氨基酸之间。所有芝麻赤霉素合成相关基因编码的蛋白质预测为亲水性蛋白。与拟南芥、水稻、大豆、葡萄、高粱、番茄等物种相比,芝麻中赤霉素合成相关基因数目处于中等水平,但CPS家族中芝麻的基因数目明显多于其他物种,进化分析表明,在分析的7个物种中,芝麻与番茄具有较近的进化关系。在不同组织中,7个相关基因家族表达模式不同。KS家族基因在种子、茎尖和叶片中表达相对较高;CPS家族基因在心皮和种子中活性较强,但在茎尖和叶片中几乎没有表达;KAO和KO家族基因在不同组织中整体上具有相对较高的活性,而KS、GA3ox家族的基因在不同组织中整体表达量较低。就不同组织而言,种子中的GA合成相关基因活性整体较高;而在根尖、茎尖、叶片等与芝麻植株形态建成密切相关的3个组织中,这些基因表达以根尖较突出、其次为茎尖,在叶片中的活性整体较低。本研究为解析芝麻赤霉素合成相关基因的结构特征及其在不同组织中的作用特点提供了基因信息和理论参考。      

Genome-wide identification of TPS genes in sesame and analysis of their expression in response to abiotic stresses

Trehalose and its precursor, trehalose-6-phosphate, play critical roles in plant metabolism and response to abiotic stresses. Trehalose-6-phosphate synthase(TPS) is a key enzyme in the trehalose synthesis pathway. Hence this study identified TPS genes in sesame(Si TPSs) and examined their expression patterns under various abiotic stresses. Totally, ten Si TPSs were identified and comprehensively characterized. Si TPSs were found to be unevenly distributed on five out of 13 sesame chromosomes and...     

Comparison of fatty acid composition,phytochemical profile and antioxidant activity in four flax (Linum usitatissimum L.) varieties

The present study evaluates variations among flaxseed varities in terms of fatty acid composition, phytochemical profile, and antioxidant activity determined by oxygen radical absorbance capacity (ORAC), 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and ferrous ion reducing antioxidant power (FRAP) assays. Significant variations in fatty acid composition, phenolic acids and lignan were observed in flaxseed varieties from different countries. Among them, unsaturated fatty acids accounted over 4/5 of total fatty acid content. The highest ratio of linolenic acid of total fatty acid was observed in USPEA, whereas the lowest one was found in Yexiao. USPEA showed the highest content of total phenolics, as well as flaxseed lignan. In general, total phenolics appeared to be the main contributors of antioxidant capacity of flaxseed, which presented significant positive correlation. Our study revealed that both cultivar and origin of seed significantly affected fatty acid composition, phenolic acids, lignans and subsequent antioxidant activity of flaxseed. These results provided new aspects of breeding resources of flaxseed cultivars by presenting their quality specification and possible commercial value.     

玉米LRR-RLK基因家族鉴定和SIF亚家族表达模式分析

富含亮氨酸重复的类受体激酶(leucine-rich repeat receptor-like kinase,LRR-RLK)能够调节植物的生长发育、参与激素信号传导、抵御各种逆境胁迫,它是植物中已知最大的跨膜类受体蛋白激酶(receptor-like kinase,RLK)家族。SIF是LRR-RLK家族中的一个亚家族,该亚家族在拟南芥和棉花中被证明参与逆境胁迫。利用生物信息学方法对玉米B73基因组的LRR-RLK家族进行全基因组鉴定、系统进化、染色体定位和基因结构分析,基于LRR-RLK家族的分类结果,选择第Ⅰ亚家族SIF作为研究对象,分析该亚家族成员组织特异性表达以及对逆境胁迫的响应模式。结果表明,玉米LRR-RLK基因家族包含249个成员,这些LRR-RLK基因非均等地分布于玉米10条染色体上。系统进化分析可将其分为15类,各亚家族基因数量分布由1～51个不等。基于转录组数据的表达模式分析表明,玉米SIF亚家族基因在不同组织及逆境胁迫下的表达量不同,发现了多个可响应非生物胁迫(干旱胁迫、冷胁迫、热胁迫和盐胁迫)和生物胁迫(玉蜀黍平脐蠕孢、禾谷镰孢、瘤黑粉菌和蚜虫)的SIF基因。     

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...