Effects of dietary fiber and phytic acid on mineral availability.

In general, it has been shown that dietary fiber may bind metallic cations in both in vitro and in vivo studies. However, there clearly are many unresolved questions on the effects of high-fiber diets on mineral availability. On one side, the effects of fiber on the utilization of nutrients vary greatly with the amount and type of fiber. In addition, there are many agents in both food and the digestive tract that may affect the mineral binding to fiber: some agents may inhibit binding, while others will enhance it. Also, there are several major difficulties in drawing conclusions from the in vitro and in vivo studies due to the different experimental conditions, methods used to follow the mineral balance, etc. Finally, it must be borne in mind that fiber and phytic acid occur together in fiber-rich diets and, thus, it is difficult to separate the effects of fiber and phytate in the utilization of most essential polyvalent metallic ions. The studies summarized in this review show that the recommendation for increasing dietary fiber in Western communities would not be expected to have any adverse effect on mineral absorption if we increase not only the intake of fiber, but also the dietary intake of other food components such as protein (both vegetable and animal protein) and ascorbic, citric, and oxalic acids (in fruits and vegetables). The adequate intake of minerals, fat, and simple sugars are maintained with this type of diet. The recommendations should be best interpreted in such a way as to prevent the consumption of excessive amounts of phytate, particularly for those whose mineral needs are great. Further studies are still needed in this field in order to understand the conflicting results published in the literature regarding the effects of fiber on the utilization of minerals; however, the studies reviewed in this article may give us an idea of the complexity of mineral availability in fiber-rich, phytate-rich diets.     

不同外源添加物协同挤压膨化黑米粉的品质比较分析

为研究不同外源添加物协同挤压膨化对黑米粉品质特性的影响,以黑米为原料,分别添加质量分数为1%的维生素C、柠檬酸、葡萄糖、碳酸钙、复合物（上述四种外源物各添加0.25%）后挤压膨化成黑米粉,评价不同外源添加物对黑米粉冲调性、粘度、糊化度、感官品质以及活性成分（膳食纤维、多酚、黄酮、花色苷含量）的影响。结果表明：相较于黑米直接挤压膨化,添加复合物后黑米粉水溶性指数提高了105.53%,吸水性指数降低了46.28%,结块率下降了53.36%;粘度显著降低,流动性增加;糊化度无显著变化,感官品质明显提升。葡萄糖或柠檬酸的添加有利于不可溶性膳食纤维和总膳食纤维含量增加,而复合物添加有利于可溶性膳食纤维含量增加。添加柠檬酸更有利于黑米粉中游离酚、结合酚、结合黄酮、花色苷等活性物质的保留,且总酚的抗氧化力提高了105.60%。综上所述,在黑米粉挤压膨化时加入不同外源添加物可以有效改善黑米粉的冲调性和感官品质,提高活性成分的保留率。该研究旨在建立一种营养活性物质高保留,且食味与应用品质兼顾的速食黑米粉加工技术。     

Antioxidants and hormone‐mediated health benefits of whole grains

Lignans and phytoestrogens have been associated with protective effect against hormone‐related diseases, for example, cancer of the breast and prostate, and potential mechanisms for this effect have been reported. Antioxidants also appear to have some protective effect against diseases associated with reactive free radicals such as coronary heart disease and cancer. Whole grains contain some of these substances particularly the mammalian lignan precursors, vitamin E, other phenolic compounds, Se, and phytic acid. These substances may in part be responsible for the reduced risk of cancer and coronary heart disease associated with intake of high‐fiber diets containing whole grains. Because they are more associated with the fiber in the outer layers of the grain, the intake of whole vs. refined grain is emphasized for optimum health benefits.     

大豆膳食纤维的湿法超微粉碎与干法超微粉碎比较研究

本实验以大豆膳食纤维的超微粉碎为基础,研究了膳食纤维先经微射流作用的湿法超微粉碎再经真空冷冻干燥处理后的物理性质(平均水分蒸发速率、膨胀力、持水力、结合水力等)的变化,同时对经研磨式干法超微粉碎后的膳食纤维进行以上物理性质测定,通过测定结果比较两种超微粉碎方法对膳食纤维物理性质的影响。结果表明,采用湿法超微粉碎能使物料平均粒径达到200nm以内,使膳食纤维的平均水分蒸发速率、膨胀力、持水力、结合水力分别从粉碎前的0.188g/min、5.89ml/g、5.42g/g、12.55g/g增大到0.475g/min、9.02ml/g、13.50g/g、25.00g/g。而干法超微粉碎能使物料平均粒径达到200～300nm以内,平均水分蒸发速率、膨胀力、持水力、结合水力分别增大到0.562g/min、8.13ml/g、12.06g/g、24.45g/g。可见干法粉碎对膨胀力、持水力、结合水力的影响不及湿法粉碎的大,却更有助于水分蒸发速率的提高。     

黑麦麸膳食纤维中酚类物质的消化特性

采用热稳定α-淀粉酶、碱性蛋白酶和糖化酶提取黑麦麸的可溶性膳食纤维(SDF)和不溶性膳食纤维(IDF),探究黑麦麸膳食纤维消化前、后多酚种类及含量的变化,消化后生物可及性和体外消化过程中抗氧化性的变化,确定可以进入胃肠中被肠道微生物利用的成分组成。结果表明,经胃肠消化后SDF和IDF中没食子酸的增加量最显著(P<0.05),SDF为497%,IDF为1 771%。随着消化时间的延长,SDF和IDF中释放的多酚呈上升趋势,进而导致抗氧化活性逐渐增强。SDF的总酚及总黄酮的生物可及性均显著(P<0.05)高于IDF,在消化结束时达到了89.51%和32.41%。结论:消化有利于促进酚类物质的释放和提高抗氧化性,有6种酚类物质,分别为阿魏酸、咖啡酸、绿原酸、没食子酸、原儿茶酸和山奈酚可能被肠道微生物利用,调节肠道健康。SDF和IDF可作为食品添加剂,提高黑麦麸的附加值。     

发酵条件对小米酸粥中多酚含量的影响及其主要组分研究

探究小米酸粥发酵过程中发酵时间及发酵温度对多酚含量的影响,并对比小米酸粥与小米粥中主要成分差异。结果显示,小米酸粥中多酚含量随时间增加而增多,在20 h处达到最大值。在32 ℃的发酵温度下,小米酸粥中多酚含量最多。与小米粥相比,小米酸粥降低了煮制导致的多酚损耗,且酸粥中多酚抗氧化活性较小米粥高。小米酸粥中蛋白、脂肪含量均较高,分别达到13.5 mg/100 g及6.2 mg/100 g,而淀粉含量较低为53.4 mg/100 g,与小米粥相比降低了8.7 mg/100 g。此外,小米酸粥发酵可增加不可溶性膳食纤维含量及上清液中的游离色氨酸含量。     

糙米制品抗氧化活性比较研究

研究以糙米为原料,制成糙米饭、糙米线和糙米速食粥3种制品,以精白米饭为对照,分析制品中多酚物质含量、膳食纤维的特性,比较评价其抗氧化活性。结果表明:总酚含量的顺序为:糙米米线(64.05±0.86 mg/100 g)>糙米速食粥(63.95±2.02 mg/100 g)>糙米饭(50.70±0.02 mg/100 g)>白米饭(20.27±0.46 mg/100 g);总黄酮含量顺序为:糙米速食粥(736.50±26.05 mg/100 g)>糙米米线(642.27±66.94 mg/100 g)>糙米饭(581.17±21.91 mg/100 g)>白米饭(186.81±14.12 mg/100 g)。3种糙米制品中总抗氧化能力差异不显著且均高于白米米饭,清除DPPH、ABTS+能力顺序:糙米速食粥>糙米线>糙米饭>白米饭(P<0.05)。制品总酚和黄酮含量与自由基的清除力具备显著的相关性(P<0.01);游离型总酚和总黄酮含量与其总抗氧化活性具有良好的相关性,相关系数分别为0.904和0.824。糙米线和速食粥的膳食纤维对脂肪酸的吸附力是米饭的2倍左右。糙米制品膳食纤维抗氧活性均高于白米饭;速食粥清除DPPH的能力是米线的2倍多,是米饭的4倍多;速食粥和米线对ABTS+清除力是米饭的3~4倍。糙米速食粥、糙米米线与米饭相比,酚类物质含量较高、膳食纤维具有较强的油脂吸附力和清除自由基的能力。     

谷物多酚与膳食纤维调控肠道菌群缓解小鼠肥胖作用研究

目的:探究谷物多酚(阿魏酸和咖啡酸)和膳食纤维(阿拉伯木聚糖和β-葡聚糖)复合物缓解高脂饮食诱导的小鼠肥胖的效果。方法:将48只雄性C57BL/6J小鼠随机分为对照组(CON)、谷物多酚和膳食纤维复合物组(PPDF)、高脂饲料组(HFD)和高脂饲料加复合物组(HFD+PPDF),自由摄食18周后,基于血液生化和组织病理学指标评价PPDF对肥胖小鼠的影响,并通过高通量测序技术分析结肠菌群组成变化。结果:与HFD组相比,HFD+PPDF组小鼠体质量增加、肝脏指数、血清谷丙转氨酶(ALT)和丙二醛(MDA)水平分别降低13.71%,12.62%,35.49%和22.97%(P<0.05);超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)活性分别提高43.12%和36.66%(P<0.05),糖耐量异常改善。PPDF增加了高脂饮食小鼠肠道菌群的多样性,其中Ace指数和Chao1指数分别升高30.07%和30.93%(P<0.05);双歧杆菌、罗氏菌属和Lachnospiraceae_NK4A136_group菌属丰度分别升高76.56%,1 727.46%和315.43%(P<0.05);而乳杆菌属、罗姆布茨菌属、丹毒荚膜菌属、Clostridium_sensu_stricto_1和布劳特氏菌属丰度分别降低68.52%,90.17%,61.39%,75.19%和95.62%(P<0.05)。相关性分析表明,双歧杆菌属和阿克曼氏菌属与体质量增加、肝脏指数和糖耐量异常呈显著负相关关系,与抗氧化活性呈显著正相关关系;而乳杆菌属、罗姆布茨菌属、丹毒荚膜菌属、Clostridium_sensu_stricto_1和布劳特氏菌属与之相反。结论:PPDF可通过增加肠道菌群多样性和有益菌丰度,改善小鼠糖代谢紊乱并预防肥胖。     

黑麦麸膳食纤维的结构和功能特性研究

以黑麦麸为原材料,采用酶法制备膳食纤维并分别测定2种膳食纤维的结构、单糖和酚类物质组成及功能特性。结果表明:可溶性膳食纤维(SDF)的表面疏松松散,主要由阿拉伯糖(68%)、半乳糖(13.1%)和木糖(12.2%)组成;不溶性膳食纤维(IDF)表面多孔不规则,主要由木糖(54%)和阿拉伯糖(38.3%)组成。两种膳食纤维均具有糖类红外特征吸收峰,IDF结晶度高于SDF,结构更加规则,SDF表现出更好的吸水力(2.19 g/g)、吸附胆固醇的能力(2.09 mg/g,pH=7)和吸附亚硝酸根的能力(327 μg/g,pH=2)。采用高效液相色谱分析SDF和IDF的酚类物质组成,IDF中的酚类物质组成及含量均显著高于SDF(P<0.05),二者的酚类化合物主要是结合型阿魏酸。     

1,2,6-三磷酸-3,4,5-三乙酸肌醇酯的制备及其抗油脂氧化活性研究

植酸水解得到1,2,6-三磷酸肌醇(PP56),PP56与三乙胺反应生成相应的铵盐.以二氯甲烷为溶剂,脂酶Novozyme 435催化,该铵盐与乙酸反应生成1,2,6-三磷酸-3,4,5-三乙酸肌醇酯.以过氧化值(POV)为指标研究不同剂量的1,2,6-三磷酸-3,4,5-三乙酸肌醇酯对菜籽油的抗氧化性能,结果表明:1,2,6-三磷酸-3,4,5-三乙酸肌醇酯对菜籽油具有明显的抗氧化作用且存在剂量效应关系,在浓度为0.06%时其抗氧化能力和0.02%BHT相当.     

Effect of grape antioxidant dietary fiber on the lipid oxidation of raw and cooked chicken hamburgers

Efficiency of four concentrations (0.5, 1, 1.5 and 2%) of grape antioxidant dietary fiber (GADF) on susceptibility of raw and cooked chicken breast hamburger to lipid oxidation was investigated after 0, 3, 5 and 13 days of refrigerated storage at 4 °C. Color changes, sensorial qualities and acceptability by panellist were evaluated. Lipid oxidation was assessed by monitoring malondialdehyde formation with 2-thiobarbituric acid (TBARS) assay and radical scavenging capacity by ABTS method. A significant reduction in lightness and yellowness and a significant increase in redness as a result of GADF addition were observed in raw and chicken hamburgers. Addition of GADF significantly improved the oxidative stability and the radical scavenging activity in raw and cooked chicken hamburgers. The ability of GADF to prevent lipid oxidation was concentration-dependent. Acceptability of chicken meat was not affected by the addition of GADF. These results show that GADF is a very effective inhibitor of lipid oxidation and has potential as a natural antioxidant in raw and chicken cooked meats.     

土豆渣微生物深加工初步研究

从98株药用真菌中,筛选出一株对淀粉和纤维素均有较强降解能力的菌株。利用该菌株发酵培养基蒸煮之后的土豆渣,可以液化土豆渣,生产富含膳食纤维的发酵产品,其中总膳食纤维含量达到18.34g/L,可溶性膳食纤维含量为1.40g/L,为土豆渣深加工提供新的途径。     

以豆渣为原料的素肉产品挤压前后营养因子含量变化

以豆渣为主要原料,采用单螺杆挤压机在豆渣含量(0%、15%、30%、45%),物料水分(40%),挤压温度(二区:140℃~150℃,三区:170℃~180℃)条件下挤压制备组织蛋白。采用三价铁沉淀法、福林酚法、芦丁标品法、酶-重量法、消化法、国标法分别测定植酸、总酚、总黄酮、胰蛋白酶抑制剂活性、体外消化率及可溶性膳食纤维含量,比较挤压前后产品各种营养因子的含量变化。结果表明:豆渣非膨化挤压后植酸、可溶性膳食纤维含量增加,总酚、总黄酮、胰蛋白酶抑制剂活性降低,体外消化率增加,各营养因子之间的相关系数挤压后降低。     

不溶性膳食纤维的提取、表征及改性研究进展

合理摄入膳食纤维对机体健康至关重要。为了开发兼顾营养、感官与健康的膳食纤维强化食品,不溶性膳食纤维的分离提取与改性研究广受关注。大量研究运用物理作用力、化学反应或酶解等手段,对样品组成、结构以及性质进行改造,以强化其在食品加工与营养健康方面功能特性。改性产物作为添加成分对于食品的加工过程、产品品质及健康功效方面具有积极影响,有利于各类膳食纤维强化产品的开发。本文对近年来国内外文献报道的不溶性膳食纤维的提取、改性及应用相关研究成果进行梳理总结,以期为调控膳食纤维功能特性、开发高品质健康功能食品提供参考。     

苹果梨果渣膳食纤维的物理特性

本研究以苹果梨果渣为原料,采用化学法分离不溶性膳食纤维,并测定了其化学组分和物理特性。结果显示,分离制得的膳食纤维中不仅含有40% 以上的纤维素,还含有0.37～0.58mg/g 的多酚物质。苹果梨膳食纤维不同颗粒度的持水力在3.96～6.75g/g 之间,持油力为1.80～2.84 g/g,溶胀力在3.05～5.17 ml/g 之间,都随膳食纤维颗粒减小而减小。色度L 值随颗粒减小而增大的同时,其感官颜色也更亮。     

米糠深加工技术的分析与评价(Ⅰ)--米糠制油及脱脂米糠的利用

米糠富含脂质、蛋白质、矿物质、维生素等多种营养物质,是一种具有很大潜力的食品资源、化工原料和药物原料.对米糠制油技术及脱脂米糠的利用技术进行了综合性评述,为米糠的综合开发利用提供参考.     

膳食纤维改性的研究进展

研究表明膳食纤维改性后具有更加优越的理化性质,通过对膳食纤维改性方法以及改性后理化性质的综述,为进一步研究膳食纤维的应用提供参考。