Antioxidant activities and total phenolic contents of various extracts from defatted wheat germ

Defatted wheat germ (DWG) is the main by-product of the wheat germ oil extraction process. Its nutritional value has well been accepted. In this study, the antioxidant properties of 30% ethanol, 50% ethanol, 70% ethanol, 100% ethanol, and aqueous extracts of DWG were measured using various in vitro assays. Among the DWGEs (DWG extracts) tested, the 70% ethanol extract showed the best DPPH radical scavenging power while the 100% ethanol extract showed the highest ABTS radical scavenging activity and reducing power. In addition, both the 70% ethanol extract and the 50% ethanol extract exhibited relatively higher antioxidant activity in linoleic acid system. The extracts in question exhibited total phenolic contents ranging from 13.98 to 16.75 mg GAE/g. DWG, as a source of natural antioxidants, can be used to formulate nutraceuticals with potential applications to reducing the level of oxidative stress. The antioxidant potency of the DWG extracts could be the basis for its health promoting potential.     

Physicochemical assessment of fresh chilled dairy dessert supplemented with wheat germ

Wheat germ is an available and economical source of protein, vitamins and antioxidants with an increasing application in food products. The main aim of this study was to investigate the effects of different levels (0.0, 2.5, 5.0, 7.5 and 10.0%) and particle sizes (120, 210 and 354 μm) of wheat germ on physicochemical properties of fresh chilled dairy dessert. With increasing wheat germ level, dry matter of the dessert increased while the pH decreased. Particle size had no significant effect on these parameters. Increasing the wheat germ content and particle size enhanced darkness, hardness, cohesiveness and gumminess of the desserts while decreasing springiness and water release of the samples. Wheat germ level had greater effects on different quality aspects of the desserts than its particle size. The most acceptable dessert was produced with no more than 5.0% wheat germ with either of the particle sizes used in this study.     

脱脂麦胚提取物抗氧化活性的研究

麦胚是面粉生产的主要副产物之一,含有多种生理活性成分,极具开发前景。主要对比分析了脱脂麦胚6种溶剂提取物的抗氧化活性。实验结果表明:水、70%甲醇、70%乙醇、50%丙酮的提取率较高,6种脱脂麦胚提取物都具有一定的DPPH自由基清除能力和还原能力,且提取物质量浓度与抗氧化活性呈现一定的量效关系,其中70%甲醇提取物和甲醇提取物的DPPH清除能力较高,70%乙醇提取物的还原能力最强。另外,6种提取物中水提取物和50%丙酮提取物的总酚含量较高,并且提取物的抗氧化活性与其总酚含量之间未呈现正比关系。     

含二十八碳醇的脱脂小麦胚芽饮料的研制

本文研究了含二十八碳醇的小麦胚芽饮料的工艺流程,确定了最佳配方和工艺要点,研究了随 着保存时间延长饮料中二十八碳醇的分布变化情况。     

Physical and nutritional evaluation of wheat cookies supplemented with pulse flours of different particle sizes

With the aim to develop functionally and nutritionally improved cookies, the influence of the total or partial replacement of wheat flour by pulses flours on the quality characteristics of cookies was analysed. Blends containing 25, 50, 75 and 100 g/100 g of navy bean, pinto bean, green lentil and commercial yellow pea flours were prepared. Green lentil, navy and pinto bean flours were used at two degrees of milling (fine and coarse). The incorporation of pulse flours significantly affected the physical and chemical parameters of the cookies. Incorporation of fine flours remarkably increased cookies’ hardness and decreased spread while coarse flours marginally reduced both parameters. The greatest impact on the physical characteristics was observed with the incorporation of green lentil flour, where cookies made with coarse flour were of unacceptable structure and were sticky to handle. Cookies baked with pulse flours were higher in protein level and showed increased antioxidant activity compared to the control. Overall analysis indicated that cookies with acceptable physical characteristics and improved nutritional profile could be produced with partial or complete replacement of the wheat flour.     

Effect of defatted maize germ flour addition on the physical and sensory quality of wheat bread

Maize (Zea mays L.) processing produces large quantities of defatted maize germ (DMG) that is being used mainly for animal feed. The objective of this study was to exploit use of this nutrient-rich by-product in bread by replacing wheat flour at 5-20 g/100 g levels. Breads prepared with wheat-DMG flour blends were analyzed for loaf volume, density, instrumental dough hardness and bread firmness, Hunter color (“L”, “a”, “b”, chroma, and hue angle), and selected sensory attributes. Loaf volumes decreased significantly, from 318.8 ml to 216.3 ml, as the DMG flour supplementation was increased from 0 to 20 g/100 g; a similar effect was observed for bread specific volume. Increase in dough hardness (7.56-71.32 N) was directly related to increase in DMG flour levels. Instrumental firmness values were significantly higher for breads containing DMG flours, 61.58 N in 20 g/100 g DMG bread versus 32.84 N for the control bread, made with wheat flour only. The control bread was lighter in color, as shown by higher “L” values, than those having DMG flour, with chroma and hue angle values significantly higher in treatment breads. In general, no differences were observed for the sensory attributes of crumb color, cells uniformity, aroma, firmness, mouthfeel, and off-flavor in breads with up to 15 g/100 g DMG flour, while the overall acceptability scores showed a mixed pattern. The results of this study demonstrated that acceptable quality bread could be made with DMG flour addition at ≤15 g/100 g.     

The use of ultrasound for enzymatic preparation of ACE-inhibitory peptides from wheat germ protein

The effects of ultrasonic treatment during proteolysis on kinetic characterisation of the hydrolysis of defatted wheat germ protein (DWGP), and on ACE-inhibitory activity of the hydrolysate, were investigated. The effects of ultrasonic pretreatment on the release of peptides with ACE-inhibitory were also studied. The results showed that the value of k_A for DWGP hydrolysis under ultrasonic irradiation increased by about 22.2%, and K_M decreased about 13.0%, compared with that obtained without ultrasound. Analysis of ACE-inhibitory activity indicated that ultrasound during enzyme treatments had less effect on the ACE-inhibitory activity, while ultrasonic pretreatment caused a 21.0–40.7% increase in ACE-inhibitory activity of DWGP hydrolysate. Analyses of hydrophobicity, microstructure, and amino acid composition revealed that ultrasonic pretreatment could accelerate the release of hydrophobic amino acids from DWGP during enzymatic hydrolysis. In conclusion, ultrasonic treatment during proteolysis could facilitate the enzymatic hydrolysis of DWGP, whereas ultrasonic pretreatment could promote the release of ACE-inhibitory peptides from DWGP during enzymatic hydrolysis.     

Comparison of functional properties and secondary structures of defatted wheat germ proteins separated by reverse micelles and alkaline extraction and isoelectric precipitation

The functional properties and secondary structures of defatted wheat germ protein separated by reverse micelles (DWGRMPI) were investigated and compared with those of defatted wheat germ protein separated by alkaline extraction and isoelectric precipitation (DWGPI). The results showed that DWGRMPI had a higher nitrogen solubility index, fat absorption capacity, foaming capacity, foaming stability and emulsifying stability compared to DWGPI, whilst water holding capacity, surface hydrophobicity and emulsifying activity of DWGRMPI were relatively lower than those of DWGPI. DWGRMPI contained high levels of threonine, histidine, alanine, arginine, glycine, serine, cysteine, proline and especially lysine compared to DWGPI. The denaturation temperature and denaturation enthalpy of DWGPI were both lower than those of DWGRMPI, and DWGPI contained more random coil and less α-helix than DWGRMPI, which suggested that DWGPI has lost its ordered secondary structure. This may possibly due to the conditions the used in protein extraction.     

小麦胚芽蛋白制备及应用

小麦胚芽蛋白是一种完全蛋白,其氨基酸全面平衡,且易于被人体吸收,在营养学上具有重要意义。该文主要对小麦胚芽蛋白营养价值、制备及其应用进行综述。     

黑曲霉发酵脱脂麦胚过程中抗氧化活性变化研究

以脱脂麦胚为原料,研究了黑曲霉（Aspergillus niger）发酵脱脂麦胚过程中发酵液抗氧化活性、蛋白酶活力和蛋白质含量的变化。结果表明,随着发酵时间在0～120 h范围内延长,发酵液对1,1-二苯基-2-三硝基苯肼（DPPH）、羟基（OH）和超氧阴离子（O2-）自由基的清除能力及其总还原力均呈现先增加后缓慢降低的趋势,在发酵84 h达到最大值,分别为75.68%、80.40%、40.7%、0.476 7（A700 nm值）;发酵液蛋白酶活力在72 h时达到最大值为269.35 U/mL,之后逐渐平稳,在发酵第108小时,发酵液中蛋白质含量达到最大值为21.92 mg/mL。该研究为发酵法制备麦胚抗氧化产品提供了一定的参考依据,有助于提升麦胚的附加值。     

响应面法优化小麦胚芽蛋白逆流脉冲超声辅助提取技术

研究小麦胚芽蛋白的超声辅助提取工艺。以脱脂小麦胚芽为原料,采用碱溶酸沉-逆流脉冲超声复合法提取其中的蛋白质,考察超声提取时间、料液温度、脉冲超声占空比、料液比等单因素对提取率的影响,确定出各因素最适取值范围;进一步采用响应面法优化工艺条件,得到小麦胚芽蛋白质提取最佳工艺:超声总时间为20 min,超声温度50℃、料液比为0.087 g/m L(1∶12)、占空比为0.625;研究表明,在此工艺条件下,蛋白质提取率为86.59%,较传统的一次碱提酸沉法提取率提高了49.06%。     

脱脂麦胚发酵过程中抗氧化活性变化研究

该实验通过测定脱脂麦胚发酵前后对DPPH、羟基、超氧阴离子、ABTS自由基的清除率以及总还原能力、多肽含量的变化,研 究了脱脂麦胚发酵过程中抗氧化活性的变化。 结果表明,脱脂麦胚发酵后,各指标均呈先增大后减小的趋势,除ABTS自由基的清除率在24 h达到最高外,其他指标均在32 h达到最高。 DPPH·、·OH、O2·、ABTS 的清除率分别提高了37.60%、8.75%、4.57%和5.76%,抗氧化活性显著提高。 多肽含量及总还原能力在发酵时间为32 h时达到最大值,吸光度值分别为0.34和0.12。     

脱脂麦胚蛋白的分离制备

本文对脱脂麦胚蛋白的分离制备分别用碱法和酶法进行了对比研究.结果表明,碱法制备脱脂麦胚蛋白的最佳工艺条件:pH值10,时间60min,温度45℃,固液比1:16,提取率为78.97%,酸沉条件:pH值4.2,得率为66.16%;木瓜蛋白酶法制备脱脂麦胚蛋白的最佳工艺条件:pH值5,时间60min,温度60℃,加酶量3000U/g,提取率可达97.98%,酸沉条件:pH值4.2,得率为78.15%.     

小麦胚芽粉对馒头品质的影响

研究了小麦胚芽粉加入量对馒头品质的影响。测定不同小麦胚芽粉加入量下制得的馒头的比容、白度、硬度以及感官评分等并观察其变化,结果显示,随着小麦胚芽粉含量的增加,馒头的白度和比容均呈下降趋势,而硬度呈现先平缓后上升的趋势,馒头的感官评分则是先增大后减小,在加入量为6%时所制得的馒头的感官评分最高。     

超声预处理对脱脂小麦胚芽酶解制备ACE抑制肽的影响

为了研究不同工作模式超声预处理对脱脂小麦胚芽水解度和ACE抑制率的影响,在相同能耗条件,利用聚能逆流单频、聚能逆流双频、脉冲扫频多频、发散三频、对振双频五种工作模式超声,对脱脂小麦胚芽进行预处理。同时进行单因素实验来寻找最佳超声预处理参数。结果表明,超声波预处理对水解度没有显著的影响,但可以显著提高酶解产物的ACE抑制活性,最佳的超声波工作模式为脉冲平板式40 k Hz/28 k Hz双频超声;在此模式下超声预处理单位体积超声功率60 W/L、超声时间70 min、超声初始温度60℃、底物浓度7%时得到的酶解产物IC₅₀值低至2.483 mg/m L,为较优结果,和未超声相比,其产物IC₅₀值降低了5.8%。      

小麦胚芽油化学组成与功能特性研究进展

小麦胚芽油是经小麦胚芽加工得到的食用油,其多不饱和脂肪酸含量60%左右,生育酚含量高达2573.69 mg/kg,远高于其他植物油,总植物甾醇含量为8512.06 mg/kg,其中β-谷甾醇高达5812.76 mg/kg。小麦胚芽油因具有丰富的营养价值以及抗氧化、抗疲劳等功能特性而被广泛应用于医疗保健、美容等领域。因此,本文主要对小麦胚芽油理化性质、营养特性进行总结,同时对比分析不同的制备工艺小麦胚芽油品质,旨在为小麦胚芽油及其副产物的开发利用提供参考。     

麦胚多糖的分离纯化及组成分析

以水为溶剂从脱脂小麦胚芽中制备的麦胚多糖,采用Sephadex-G100柱层析进行分级,得到2种组分WGPⅠ和WGPⅡ。其中WGPⅡ,完全酸水解后,经HPLC测定,主要由葡萄糖、木糖、阿拉伯糖3种单糖组成。     

麦胚奶片的开发制备

本文介绍了以麦胚、奶粉为主要原料制成麦胚奶片的工艺，还探讨了制备过程中遇到的问题及解决方法。     

麦胚钙片的研制

对麦胚钙片的加工工艺及产品配方进行了初步研究 ,研制出了营养丰富、口感良好、含钙量较高的保健型咀嚼片。