Effects of high hydrostatic pressure on the RS content of amaranth,quinoa and wheat starch

RS exerts a range of beneficial effects on human health. Therefore, ways to increase the RS content in processed food products are looked for. The effects of high hydrostatic pressure treatments on the RS content of wheat, quinoa and amaranth starch were analysed in this study. A 2³ factorial screening design of experiments was used. Experimental factors were pressure (100–600 MPa), temperature (40–60°C) and time (10–30 min). RS in wheat starch increased with increasing pressure by a factor of up to 10 to a value of 4%. In detail, RS content increased significantly at pressures higher than 100 MPa in wheat starch, whereas in quinoa starch significant changes occurred at pressures above 350 MPa (up to 3.3% RS compared to 0.2% in native quinoa starch). Contrary, in amaranth starch the RS content of all pressure treated samples (about 0.5%) was lower than that of the native starch (1.3%). Wheat starch granules swelled to a maximum of 3.67 times their original size and quinoa starch up to 3.36 times. The extent of swelling (2.90) was lowest in amaranth starch.     

Phenolic,apparent antioxidant and nutritional composition of quinoa (Chenopodium quinoa Willd.) seeds

Quinoa, a gluten-free pseudocereal, has a nutrient and phytochemical profile which may benefit health. Our aim was to investigate the variability in the phenolic and apparent antioxidant content of different quinoa varieties to identify a variety with a high phytochemical content to use in a quinoa-enriched bread. The results showed that free phenolics contributed most (50–83%) to total phenolic content compared with conjugated or bound forms. Apparent antioxidant activities measured by FRAP, ABTS+• and DPPH of free, conjugated and bound extracts were broadly similar, except for free antioxidants when determined by FRAP, which were higher. Phenolic content was positively correlated with FRAP and ABTS+• apparent antioxidant activity. Quinoa samples had a high protein content (13.5 g/100 g dry weight), with a well-balanced amino acid profile. Incorporation of quinoa into baked products such as bread is proposed as a way to deliver this healthy whole-grain cereal into the diet.     

Antioxidant activity of amaranth protein or their hydrolysates under simulated gastrointestinal digestion

Amaranth proteins were subjected to a simulated gastrointestinal digestion to evaluate the antioxidant activity of the products. A protein isolate (I) was first hydrolyzed with pepsin (Pe) (pH 2, 37 °C) and then with pancreatin (Pa) (pH 6, 37 °C). Different hydrolysis conditions were assayed and control reactions (without enzymes) were performed. Hydrolysis degree (HD) determined by TNBS method ranged from 13 to 37%. Soluble fractions in 35 mmol/L phosphate buffer, pH = 7.8 were obtained from freeze-dried samples, and antioxidant activity was evaluated by the ABTS⁺·scavenging and the ORAC assays. Antioxidant activity increased significantly (p < 0.05) after simulated gastrointestinal digestion. According to the results, digestion conditions (Pe/protein: 1:10, 60 min; and Pa/protein: 1:10, 60 min) were selected and applied to an amaranth protein alcalase-hydrolysate (H) (HD = 29.2 ± 1.3). After pepsin and pancreatin action (Hpepa), HD was 42.0 ± 2.6, slightly higher than that of the digested isolate (Ipepa) (36.9 ± 0.5). The corresponding soluble fractions exhibited different electrophoretic profiles (tricine-SDS-PAGE) and gel filtration chromatograms, evidencing the presence of different molecular species. Previous hydrolysis with alcalase did not improve the antioxidant activity after simulated gastrointestinal digestion according to the methodologies assayed. Both the protein isolate and the alcalase-hydrolysate showed a potential capacity to scavenge free radicals after gastrointestinal digestion, appearing as promising ingredients to formulate functional foods with antioxidant activity.     

藜麦水解蛋白肽制备及其抗氧化活性研究

目的 使用蛋白酶水解藜麦蛋白,制备抗氧化性高的藜麦多肽。方法 通过单因素和响应面法优化,以1,1-二苯基-2-苦基肼自由基(1,1-diphenyl-2-picrylhydrazyl radical, DPPH·)清除率为指标,运用电子顺磁共振(electron paramagnetic resonance, EPR)技术,通过EPR波谱图分析,直接、准确地研究藜麦多肽的抗氧化活性。结果 根据所得EPR波谱图进行分析, 5种蛋白酶(复合蛋白酶、木瓜蛋白酶、胰蛋白酶、中性蛋白酶、碱性蛋白酶)的产物均有抗氧化性,胰蛋白酶处理所得物的DPPH·清除率最大,选择胰蛋白酶进行工艺优化,根据响应面模型对条件进行优化,得到最佳工艺条件是:酶添加量为2000 U/g、pH为7.2、温度为43.6℃、时间为4.30h。以优化所得最佳条件进行验证,藜麦抗氧化肽的DPPH·清除率为49.56%。结论 胰蛋白酶在最优条件下水解藜麦蛋白,可生产抗氧化性高的藜麦多肽。本研究为酶解藜麦蛋白生产抗氧化肽工艺提供了数据积累,有利于藜麦功能性产品的进一步研发。     

藜麦多肽的制备及其抗氧化活性研究

目的 优选复合酶协同超声辅助法提取藜麦蛋白的工艺以及探讨藜麦多肽的抗氧化活性。方法 采用 Box-Behnken 响应面法,对超声辅助糖化酶-纤维素酶复合酶法进行优化。使用碱性蛋白酶、菠萝蛋白酶、风味蛋白酶、木瓜蛋白酶、酸性蛋白酶、胰蛋白酶和胃蛋白酶制备藜麦多肽,通过 DPPH 法和 ABTS 法对其抗氧化活性进行探究。结果 根据响应面模型对复合酶超声辅助提取条件进行优化, 得到最佳提取条件：总加酶量 400 U/g、pH 5.0、时间 60 min。以最佳优化条件提取,藜麦抗氧化肽的 DPPH 自由基清除率最高达到 79.64%;ABTS 自由基清除率最高达到 76.14% 。结论 采用响应面法建 立的模型相对准确,藜麦蛋白的提取工艺优化方法可行;藜麦蛋白木瓜蛋白酶水解物具有较好的抗氧化活性,为藜麦作为功能食品深入开发提供依据。     

Effect of amaranth seeds in diet on oxidative status in plasma and selected tissues of high fructose-fed rats

The aim of this study was to assess the influence of amaranth seeds in different doses, under conditions of oxidative stress induced by dietary fructose, on antioxidant status of selected rat tissues, erythrocytes and plasma. Fructose administration caused oxidative stress that was manifested by the increase in plasma malondialdehyde and by the decrease in the enzymatic antioxidant activity. Co-administration of amaranth seeds influenced the oxidative stress, as was evidenced by decreasing malondialdehyde in plasma and changing the activities of antioxidant enzymes (erythrocyte superoxide dismutase, catalase, and plasma glutathione peroxidase). Our findings demonstrate that amaranth seeds can act as a moderate protective agent against fructose-induced changes. Our results suggest that the antioxidative system of plasma, heart and lungs is more efficient when amaranth seeds are present in the diet.     

Effects of quinoa and amaranth on zinc,magnesium and calcium content in beer wort

Pseudocereals such as quinoa and amaranth can be used as partial replacements for malt in the production of new beers. Quinoa and amaranth are of interest due to their high levels of nutrients and micronutrients, including minerals which can significantly improve the performance of brewing yeast and the fermentation rate. In this study, we investigated whether the use of quinoa or amaranth as partial replacements for malt affected the concentration of ions such as zinc and magnesium in beer wort. The use of amaranth, and in particular quinoa, increased the content of both zinc and magnesium ions substantially, even when only 10% of the barley malt was replaced. With 10% quinoa, Zn²⁺ and Mg²⁺ content increased by 41% and 49%, respectively, while the ratio of Mg²⁺ to Ca²⁺ rose from 1.4:1 to 1.9:1. Use of unmalted quinoa and amaranth appears a good way of enriching wort with essential metal ions.     

Amaranth,quinoa and oat doughs: Mechanical and rheological behaviour,polymeric protein size distribution and extractability

The rheological characteristics, static and dynamic mechanical properties of amaranth, quinoa and oat doughs and the relative size distribution of their polymeric proteins were evaluated. For the sake of comparison, semolina dough rheological and mechanical properties and the relative size distribution of proteins were also determined.     

Protein deterioration and longevity of quinoa seeds during long-term storage

Seed protein stability and seed deterioration during storage were studied in seeds of two different quinoa (Chenopodium quinoa Willd.) cultivars, i.e., cv. Ollagüe and cv. Baer II. Germination and viability tests proved that cv. Baer II was more longevous than cv. Ollagüe. Protein insolubilisation was detected during storage and correlated with longevity. However, protein solubility was restored by priming in both cultivars, disregarding their germination capability. Extremely high contents of advanced glycation end-products (AGEs), assessed by carboxymethyllysine (CML) quantification, were obtained from stored seeds as viability was reduced; primed seeds showed slightly lower AGE content, indicating a strong association between quinoa seed ageing and Maillard products accumulation. High intensity fluorescence values were observed in seeds stored in the gene bank bearing 100% germination values, which indicate that the detection of fluorescence is not by itself an appropriate indicator of protein damage by Maillard-type product accumulation in quinoa seeds. This work establishes for the first time a direct association between seed viability and AGE accumulation, due to Maillard reaction, in quinoa seeds.     

Nutritional evaluation and antioxidant activity of sesame sprouts

Sesame sprouts are consumed as vegetables in Asian folk. In this study, the nutritional evaluation and antioxidant activity of sesame sprouts were investigated. As seeding days progressed, the free amino acids, γ-aminobutyric acid and total phenolic compounds in the sprouts were rapidly increased while sesamin was reduced. Although a fatty acid composition analysis showed that sesame sprouts were abundant in unsaturated fatty acids, the crude fat content was gradually reduced during sprout growth. In the antioxidant assays, it was found that the DPPH radical scavenging activity and the reducing power of the sprouts increased as the seeding days progressed, which was positively related to the total phenolic content. Sesame sprouts can be recommended for functional ingredients, as well as being an excellent dietary source of natural antioxidants.     

Anthocyanins profile,total phenolics and antioxidant activity of black currant ethanolic extracts as influenced by genotype and ethanol concentration

Ethanolic extracts prepared from the fruits of three cultivars of black currant (‘Record’, ‘Blackdown’ and ‘Ronix’) macerated in three concentrations (40%, 60% and 96%) of aqueous ethanol were investigated for their anthocyanins profile, total phenolics and antioxidant activity.     

In vitro bio-accessibility and antioxidant activity of grape polyphenols

The bio-accessibility (the release of compounds from solid food matrices) of grape polyphenols using an in vitro model simulating gastro-intestinal conditions has been investigated. In vitro studies are needed to unravel factors affecting the release of antioxidants during digestion. The amount of bio-accessible polyphenols, flavonoids and anthocyanins increases during gastric digestion. The transition in the intestinal environment causes a decrease in all the analyzed classes of polyphenols followed by a renewal in the extraction of polyphenols and flavonoids but not of anthocyanins. The stability under gastro-intestinal conditions of pure phenolic acids, flavonoids and resveratrol has been analysed. Gastric digestion had no effect on any phenolic tested. Phenolic acids and resveratrol were degraded under pancreatic conditions whereas catechin and quercetin were not. Changes in antioxidant activity during digestion were correlated to the changes in polyphenols concentration as well as to the pH. Our results suggest that the gastro-intestinal tract may act as an extractor where polyphenols are progressively released from solid matrix and made available for the absorption or to exert their biological effects in the gastro-intestinal tract.     

Evolution of the colour,antioxidant activity and polyphenols in unusually aged Sherry wines

The present paper reports the results of a study monitoring several key analytical parameters in a set of aged samples of vintages from 1999 back to 1935. The analysed parameters were: colour, antioxidant activity, low molecular weight phenolics, index of total polyphenols and SO₂ content.     

桑葚提取物中花青素分析及其体外抗氧化活性研究

为了研究桑葚提取物中花青素的组成、含量及其体外抗氧化活性,采用高效液相色谱与质谱联用法对桑葚提取物中的花青素组成进行鉴定。以矢车菊素-3-O-葡萄糖苷为标准品测定了花青素的含量,并测定桑葚提取物的体外抗氧化活性。结果表明,桑葚提取物的总花青素含量为314. 30μg/mg,其中共有3种花青素,分别为矢车菊素-3-O-葡萄糖苷、矢车菊素-3-O-芸香糖苷和矢车菊素;体外抗氧化试验表明,桑葚提取物的DPPH、ABTS+和羟基自由基清除能力的IC50值分别为22. 33、12. 90和1. 74 mg/mL,在桑葚提取物质量浓度为250μg/mL时,其还原力达到0. 744。桑葚提取物中花青素含量高,且具有良好的抗氧化活性,该研究为桑葚提取物的开发利用提供了理论依据。     

豆类种子及其芽苗菜的营养品质、功能性成分及抗氧化性研究

为阐明萌发对黑大豆(Glycine max)、红小豆(Vigna angularis)和豌豆(Pisum sativum L)的影响,研究了其种子及萌发后形成芽苗菜的生长特性(总质量、可食部分鲜重、可食率、苗长、含水量)、营养品质(粗蛋白和可溶性糖含量)、功能性成分(总酚、总黄酮含量)和抗氧化性(DPPH自由基清除力、ABTS自由基清除力、FRAP亚铁还原力)。结果表明,3个豆类种子中,黑大豆的营养品质、酚类含量和抗氧化性显著高于红小豆和豌豆。3个豆类芽苗菜以豌豆苗的总质量(12.83 g/10株)、苗长(16.02 cm)和含水量(93.82%)最高;黑大豆芽苗菜的可食部分鲜重(5.87 g/10株)和可食率(71.03%)最高;豌豆苗的可溶性糖含量(0.75 mg/g)、总黄酮含量(7.09 mg/g DW)最高;黑大豆芽苗菜的总酚含量(4.28 mg/g DW)最高、ABTS自由基清除力(110.39μmol/g DW)和FRAP亚铁还原力(75.52 mmol/g DW)最强。萌发显著降低了3个豆类的可溶性糖含量,提高了粗蛋白含量;黑大豆萌发以后酚类含量和抗氧化性显著降低,而红小豆和豌豆萌发后显著提高了其酚类含量和抗氧化性。此外,酚类含量与抗氧化性之间存在着显著的正相关性。因此,黑大豆种子、红小豆芽苗菜和豌豆芽苗菜具有较高的营养价值,含有丰富的酚类物质和抗氧化性。     

Resveratrol,total phenolic and flavonoid contents,and antioxidant potential of seeds and sprouts of Korean peanuts

Peanut sprouts are gaining increasing popularity as a potential source of functional food. The objective of this study was to investigate yield and food value of peanut sprouts of six Korean peanut genotypes (Daekwang, Akwang, Baekjung, Alogi, Pungan and Heugttangkong) from day 5 through 9. Functional compounds like polyphenol, flavonoid, and resveratrol contents were significantly (p?<?0.05) high in the sprouts compared to those in the seeds. Pungan yielded significantly (p?<?0.05) high sprouts followed by Alogi. However, antioxidant potentials and functional compounds in the sprouts varied significantly (p?<?0.05) with genotype, sprout part, and day after germination. Overall consideration of the yield, functional compounds, and antioxidant potentials of the sprouts suggested that more appropriate time of sprout harvest for Alogi and Pungan was day 5–7 and that for the other genotypes was day 5–8. The yield and functional properties of peanut sprouts significantly varied with genotypes, parts, and age.     

藜麦蛋白的提取及功能性质与生物活性概述

藜麦被认为是一种营养均衡且全面的假谷物,与传统谷物相比,藜麦蛋白质含量丰富,氨基酸比例均衡,在蛋白质功效比、生物学价值和营养指数等方面都饱具优势。本文主要综述了藜麦蛋白的提取方法和功能性质的研究进展,并对其营养价值和生物活性作了简要概述,目的是为藜麦蛋白的深入研究和相关产品开发提供参考。     

Effect of salt stress on phenolic compounds,glucosinolates, myrosinase and antioxidant activity in radish sprouts

The germination, growth, total phenolics, glucosinolate, myrosinase and antioxidant activity of radish sprouts germinated under 0 (control), 10, 50 and 100 mM of NaCl were investigated. The glucoraphasatin (4-methylthio-3-butenyl-glucosinolate), total glucosinolate and total phenolic contents of 5- and 7-day-old sprouts treated with 10 and 50 mM of NaCl were significantly decreased. However, the antioxidant activity of sprouts treated with 10 and 50 mM of NaCl was not affected. The glucoraphasatin and total glucosinolate contents of 5- and 7-day-old sprouts, total phenolic contents of 3- and 5-day-old sprouts were significantly increased and myrosinase activities of 3- and 5-day-old sprouts were inhibited, although the germination was dramatically inhibited by 100 mM of NaCl treatment. These results indicated that salt stress (100 mM of NaCl treatment) could improve the nutritional value of radish sprouts, and germination of sprouts under adequate salt stress could be one useful way to enhance health-promoting compounds of plant food.     

Identification of polyphenols in tobacco leaf and their antioxidant and antimicrobial activities

Crude polyphenols were extracted from tobacco leaf by 80% ethanol solution with ultrasonic treatment and then purified by a macroporous resin. The polyphenols from tobacco leaf (PTL) were subjected to analyses by reverse-phase high-performance liquid chromatography (RP-HPLC) and electrospray ionization mass spectrometry (ESI-MS). The dominant polyphenols in tobacco leaf were identified as chlorogenic acid and rutin. Furthermore, the antioxidant activities of PTL were investigated, including scavenging activities of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals (5.02 μg/ml IC₅₀ value), hydroxyl radicals (49.6 μg/ml IC50 value) and superoxide anion radicals (44.0 μg/ml IC₅₀ value), inhibition activity of lipid peroxidation (132 μg/ml IC₅₀ value) and reducing power. The proliferation inhibition activities on Escherichia coli, Staphylococcus aureus and Bacillus subtilis were also measured for evaluating the antimicrobial activity of PTL. The diameters of inhibition zones were 20.23 ± 0.42, 17.66 ± 0.86 and 12.89 ± 0.29 mm, respectively. The results showed that PTL had great potential as antioxidant and antimicrobial agent.     

Changes in growth and antioxidant status of alfalfa sprouts during sprouting as affected by gamma irradiation of seeds

Viking 3000 alfalfa seeds irradiated with gamma rays to doses of 0, 1, 2, 3, or 4 kGy were sprouted and allowed to grow for up to 8 days at 23 degrees C. Germination, growth (yield and length), antioxidant capacity, and ascorbic acid (AA) were measured during sprouting. Results showed percent germination of the seeds and the rates of growth of the sprouts were inversely related to the radiation dose absorbed by the seeds. Both antioxidant capacity and AA content expressed on a fresh weight basis decreased during growth of the sprouts. Sprouts grown from irradiated seeds had greater antioxidant capacity and AA content on a fresh weight basis than those grown from nonirradiated seeds. However, when the nutritive values were expressed on a per gram of seed basis, irradiation had no effect on the nutritive values of sprouts.