Nutritional composition and flavonoids content of flour from different buckwheat cultivars

Thirty nine buckwheat cultivars were collected from China, of which twenty one were tartary buckwheat and others were common buckwheat. Flour samples from these cultivars were analysed for colour properties, nutritional composition and flavonoid content. Buckwheat cultivars exhibited high variations for each of these parameters. The flour of common buckwheat showed a higher whiteness index than that of tartary buckwheat and contained very low levels of flavonoids. On average, the tartary buckwheat flour contained a higher level of ash (2.38%) and lower levels of total starch (70.22%), amylose (22.32%), resistant starch (17.66%) than the common buckwheat flour (2.17%, 73.69%, 23.01%, 18.69% respectively) (P < 0.05) whereas the contents of proteins, fats and crude fibres of the tartary buckwheat flour were similar to those of common buckwheat flour. The Mei‐Hua‐Shan tartary buckwheat flour contained the highest level of total flavonoids and quercetin (22.74 mg g^?1 and 2.38 mg g^?1, respectively).     

Comparison of phenolic compositions between common and tartary buckwheat (Fagopyrum) sprouts

The phenolic compositions of non-germinated/germinated seeds and seed sprouts (at 6–10 day-old) of common (Fagopyrum esculentum Möench) and tartary (Fagopyrum tataricum Gaertn.) buckwheats were investigated. Phenolic compounds, including chlorogenic acid, four C-glycosylflavones (orientin, isoorientin vitexin, isovitexin), rutin and quercetin, were determined in the seed sprouts by high-performance liquid chromatography (HPLC). In the edible parts of common buckwheat sprouts, individual phenolics significantly increased during sprout growth from 6 to 10 days after sowing (DAS), whereas in tartary buckwheat sprouts they did not. While the sum contents of phenolic compounds in the edible part (mean 24.4 mg/g DW at 6–10 DAS) of tartary buckwheat sprouts were similar to those of common buckwheat sprouts, rutin contents in the non-germinated/germinated seeds (mean 14.7 mg/g DW) and edible parts (mean 21.8 mg/g DW) of tartary buckwheat were 49- and 5-fold, respectively, higher than those of common buckwheat. Extracts of the edible parts of both species showed very similar free radical-scavenging activities (mean 1.7 μmol trolox eq/g DW), suggesting that the overall antioxidative activity might be affected by the combination of identified phenolics and unidentified (minor) components. Therefore, buckwheat seed sprouts are recommended for their high antioxidative activity, as well as being an excellent dietary source of phenolic compounds, particularly tartary buckwheat sprouts, being rich in rutin.     

不同光照对荞麦芽黄酮类化合物及相关代谢酶基因表达的影响

通过分析不同品种荞麦的发芽形态及发芽后总酚、总黄酮的含量,从10 个荞麦品种（7 个苦荞和3 个甜荞）中筛选出2 个最适合生产荞麦芽的品种：‘蒙古2号’苦荞和‘西农9976’甜荞。将筛选出的品种进行不同发光二极管（light-emitting diode,LED）光照发芽处理,比较荞麦芽中总酚及黄酮的含量,同时分析不同光照下苦荞芽中苯丙氨酸解氨酶、黄酮醇合酶、查耳酮合酶及查耳酮异构酶的基因表达,探讨其作用机理。结果表明,‘蒙古2号’提高黄酮类化合物含量的最佳处理方式是白光光照,其中荭草苷、异荭草苷含量分别提高了63%、69%（发芽6 d）,总黄酮含量提高了40%～53%（发芽2～6 d）;‘西农9976’提高黄酮类化合物含量的最佳处理方式是红光光照,其中芦丁含量提升70%（发芽6 d）,总黄酮含量最多提高111%（发芽2～6 d）。荞麦芽中总酚含量均是在红光作用下提高最多,其中‘西农9976’总酚含量最多提高83%（发芽2～6 d）,且光照处理可明显上调4 种代谢酶基因的表达水平。     

微波协同L-苯丙氨酸处理对苦荞萌发中黄酮的影响

以川乔1号苦荞种子为研究对象,研究微波处理协同营养液L-苯丙氨酸(L-Phe)处理富集发芽苦荞黄酮效果.采用单因素和CCD响应面优化的方法,以苦荞芽中黄酮含量为指标,优化微波协同L-Phe处理下苦荞萌发富集黄酮的最佳工艺,并采用高效液相色谱法(HPLC)对苦荞芽中黄酮成分进行分析.结果表明,最优富集工艺为:苦荞种子经消...     

苦荞萌发物中生物活性黄酮对人乳腺癌细胞增殖的抑制作用

以萌发期(1～6d)的苦荞芽粉为原料,采用铝盐显色可见分光光度法和HPLC 法,探明萌发期(1～6d)苦荞芽粉乙醇提取物中总黄酮、芦丁和槲皮素含量的变化趋势。以人乳腺癌细胞MCF-7 为模型,采用噻唑蓝(MTT)比色法,比较萌发期(1～6d)的苦荞芽粉乙醇提取物对人乳腺癌细胞体外的增殖抑制率。结果表明：苦荞芽粉乙醇提取物具有抑制MCF-7 乳腺癌细胞增殖的作用,尤以萌发第3 天(芦丁与槲皮素含量比为0.92:1)时抑制效果最好,显示二者具有良好的协同抑制效果;苦荞芽粉乙醇提取物的抑制效果与槲皮素和芦丁标准品模拟样品抑制效果相似,表明苦荞芽粉乙醇提取物对MCF-7 细胞的生长起抑制作用的主要功效成分为槲皮素和芦丁。     

苦荞麦中黄酮成分剖析

苦荞麦中富含黄酮,通过对苦荞麦中各部分黄酮的测定,结果发现,苦荞麦皮中黄酮含量较高。     

苦荞麦中黄酮成分剖析

苦荞麦中富含黄酮，通过对苦荞麦中各部分黄酮的测定，结果发现，苦荞麦皮中黄酮含量较高。     

Effect of slightly acidic electrolysed water on functional components,antioxidant and α-glucosidase inhibitory ability of buckwheat sprouts

The effect of slightly acidic electrolysed water (SAEW) on the accumulation of total phenolics (TP), total flavonoids (TF), rutin, quercetin and D-chiro-inositol (DCI), the antioxidant and α-glucosidase inhibitory abilities of germinated buckwheat was investigated. The buckwheat treated in low available chlorine concentration (ACC) of 10.94 mg L^-1 displayed the best accumulation of the bioactive substance, showing 63.0%, 113.07% and 128.1% higher TP, TF and rutin content on the 9th day, respectively, and 163.5% and 113.4% higher quercetin and DCI content on the 7th day, respectively, compared to control. Seven-day sprouts treated with SAEW had markedly stronger ABTS radical scavenging and α-glucosidase inhibitory capacities compared to the other treatments. SAEW with lower ACC had less adverse impact on the length and fresh weight of buckwheat than SAEW with higher ACC. Buckwheat sprouts should be treated by SAEW with lower ACC and harvested on the 7th day as for enhanced health-promoting benefits.     

提高苦荞醋黄酮含量的工艺研究

液态发酵苦荞醋过程中黄酮损失大,发酵液由于多糖含量高导致黏稠度大而影响生产。该实验以经过多糖、黄酮提取的苦荞粉为原料酿制苦荞醋,再将所提取的黄酮添加到苦荞醋中,在同样条件下以未提取多糖、黄酮的苦荞粉酿造苦荞醋为对照,探究苦荞破碎度、糊化与否、糖化时添加不同蛋白酶等条件对苦荞粉酿醋的影响。结果表明,苦荞破碎度＞40目、糖化后添加中性蛋白酶、不糊化等条件下,将提取的黄酮加入处理过的苦荞粉所酿制的苦荞醋中可有效提高黄酮含量,酿制的苦荞醋黄酮含量（5.20 mg/mL）,比对照（3.02 mg/mL）提高了72.19%。     

Optimisation of the combined treatments of aqueous chlorine dioxide,fumaric acid and ultraviolet‐C for improving the microbial quality and maintaining sensory quality of common buckwheat sprout

The effects of the combined treatments with aqueous chlorine dioxide (ClO₂), fumaric acid and ultraviolet‐C (UV‐C) on the microbial quality of common buckwheat sprouts were examined using a response surface methodology. The populations of total aerobic bacteria, yeast and mould, and coliform decreased with increasing aqueous ClO₂ and fumaric acid concentrations and increasing UV‐C irradiation dose. However, the increase in the UV‐C irradiation dose had a negative effect on the sensory quality. Therefore, the optimal combined treatment condition of 100 ppm aqueous ClO₂, 0.31% fumaric acid and 1.9 kJ m^?2 UV‐C was selected for the buckwheat sprouts by providing reductions of 3.9, 1.8 and 2.4 log CFU g^?1 on the populations of total aerobic bacteria, yeast and mould, and coliform, respectively. The combined treatment also maintained an acceptable sensory quality. These results suggest that the optimised combined treatment can be used as a microbial inactivation method for buckwheat sprouts.     

微酸性电解水对苦荞芽活性成分及抗氧化能力的影响

以苦荞为原料,将不同有效氯浓度（available chlorine concentration,ACC）的微酸性电解水（slightly acidic electrolyzed water,SAEW）应用于芽苗菜生产,研究其对苦荞芽活性成分及其抗氧化能力的影响。结果表明：SAEW处理组苦荞芽活性成分含量相比对照组有所增加,ACC为20 mg/L的SAEW处理的苦荞芽总酚、总黄酮及芦丁含量相比自来水对照组分别提升了28.69%、26.19%和29.08%。SAEW处理萌发的苦荞芽在生长7 d内苯丙氨酸解氨酶比活力均高于自来水对照组。苦荞芽的抗氧化活性物质含量与其抗氧化能力间呈显著正相关。     

苦荞菜中总黄酮的测定

目的测定苦荞菜中总黄酮的含量。方法可见分光光度法。结果在420 nm波长处测得即食型苦荞菜中的总黄酮含量为6．87%;苦荞芽苗在生长1,3,5,7 d的总黄酮含量分别为3．31%,4．19%,4．20%,4．15%。结论苦荞菜中富含黄酮,具有广阔的开发前景。测定方法操作简单、快速,适合中、小型食品加工企业应用。     

Composition and antioxidative properties of the flavonoid-rich fractions from tartary buckwheat grains

Tartary buckwheat, a healthy food, is associated with a reduced risk of certain human chronic diseases; however, its bioactive components are unknown. This study used high performance liquid chromatographyphotodiode array-mass spectroscopy (HPLC-PDA-MS) to identify the flavonoids in flavonoid-rich fractions (FRFs) from tartary buckwheat grain and tested antioxidative capacity of FRFs to confirm their bioactivity. Ultraviolet (UV) absorption and electrospray ionization (ESI⁻) MS/MS spectra identified several flavonols in the embryo, endosperm, testa, and hull, including the predominant flavonoid rutin and minor flavonoids quercetin 3-O-rutinoside-3′-O-β-glucopyranoside, kaempferol 3-O-rutinoside, and quercetin. Tartary buckwheat FRFs extended the Rancimat induction period of lard less than common buckwheat FRF did, while their scavenging rate of DPPH free radicals exceeded that of common buckwheat FRF and rutin. These results indicate that tartary buckwheat FRFs from the grains have potential health benefits.     

Changes in nutritional composition,enzyme activities and bioactive compounds of germinated buckwheat (Fagopyrum esculantum M.) under unchanged air and humidity conditions

The objective of this study was to investigate changes in nutritional and bioactive compounds in buckwheat seeds during germination under unchanged air and humidity conditions. The germination increased the crude protein, total lipid, reducing sugars, essential amino acids (EAA) and polyunsaturated fatty acids, but decreased the total ash, total carbohydrate and saturated fatty acids. After germinating for 48 h, the total EAA and polyunsaturated fatty acids significantly increased by 5.22% and 3.66%, respectively, as compared to those of ungerminated buckwheat. The total phenolics and flavonoids contents of both free and bound phenolic extracts of germinated buckwheat were also significantly higher than those of ungerminated buckwheat. The rutin content was found to gradually increase during germination, whereas the quercetin content was the highest in the 36 h-germinated buckwheat (0.26 mg g⁻¹ flour). Therefore, germinated buckwheat is considered as a potential material for producing healthy functional foods.     

Antioxidant properties of tartary buckwheat extracts as affected by different thermal processing methods

The effects of roasting, pressured-steam heating and microwave heating on total phenolics, total flavonoids, and antioxidant properties of whole-meal flour from tartary buckwheat (Fagopyrum tataricum Gaertn.) were investigated. The total phenolics were evaluated by Folin-Ciocalteau assay, total flavonoids by aluminum nitrate colorimetric assay whilst antioxidant properties were based on free radical scavenging activity of flour extracts against hydroxyl and superoxide anion radicals, and inhibition of lipid peroxidation in vitro. This study showed that thermal treatment of buckwheat flour caused a decrease in total phenolics, total flavonoids and antioxidative activities. The changes in trend of the antioxidant activities due to the thermal treatment were positively correlated with the content of phenolics (R² = 0.8401-0.9909). Therefore, it can be suggested that special care should be taken when processing method is selected for the exploration of tartary buckwheat products.     

Effects of light sources on major flavonoids and antioxidant activity in common buckwheat sprouts

It is known that flavonoids in sprouts were accumulated more under light irradiation than under dark. Light source affecting flavonoid accumulation in sprouts is still investigating. We evaluated the effects of light sources, including red, blue and fluorescent lights, on the flavonoid accumulation and antioxidant activity in common buckwheat sprouts. Experimental results showed that blue light significantly enhanced the contents of C-glycosylflavones, including orientin, vitexin and their isomers, and rutin and a rutin isomer. Sprouts grown under blue light exhibit also the highest total phenolics and total flavonoids as well as the highest antioxidant activities. It was found that isoorientin is the highest antioxidant flavonoid whereas numerous former studies suggested that rutin is a typical antioxidant compound in common buckwheat. These results indicated that blue light could be applied for enhancing not only the content of flavonoids but also antioxidant activity in common buckwheat sprouts.     

Rutin and flavonoid contents in three buckwheat species Fagopyrum esculentum,F. tataricum,and F. homotropicum and their protective effects against lipid peroxidation

This study was conducted to investigate the rutin content of three buckwheat species: Fagopyrum esculentum, Fagopyrum tataricum and Fagopyrum homotropicum, and to evaluate their antioxidant capacity. In total, 11 cultivars/accessions were analyzed. The contents of both rutin and total flavonoids were significantly different depending on species, 0.02% and 0.04% in F. esculentum, 0.10% and 0.35% in F. homotropicum, and 1.67% and 2.04% in F. tataricum, respectively. Three buckwheat species exhibited a dose–response effect in inhibiting low-density lipoprotein (LDL) peroxidation. The antioxidant activity decreased in the order: F. tataricum > F. homotropicum > F. esculentum. Linear regression analysis revealed a correlation between antioxidant activity and rutin content (R² = 0.98) or total flavonoids content (R² = 0.77) in all buckwheat cultivars/accessions. This work shows that rutin plays an important role in antioxidant activity of buckwheat seed. It provides useful information for buckwheat breeding to develop high rutin content varieties.     

萌发对苦荞籽粒品质的影响及工艺优化

以苦荞籽粒为原料,分析了浸种和萌发温度及时间对苦荞籽粒总黄酮含量、γ-氨基丁酸(GABA)含量、DPPH自由基清除率、发芽率及芽长的影响,并优化了其萌发工艺条件。结果表明,苦荞籽粒的最佳萌发条件为:浸种温度20℃、浸种时间8h、萌发温度26℃、萌发时间98h。该条件下,萌发苦荞的总黄酮含量为10.34mg/g,是对照组的2.27倍;GABA含量为2.86mg/g,是对照组的1.17倍。制茶后,萌发苦荞茶总黄酮质量浓度为7.678mg/100mL,是对照组的3.71倍;GABA质量浓度为13.142mg/100mL,是对照组的1.63倍;茶汤的颜色、透明度、香气、滋味、总分等感官评分均优于对照组。萌发处理可以提高苦荞茶的总黄酮含量、GABA含量及感官品质。