还原前后大豆球蛋白酶解物的性质

主要研究了还原前后大豆球蛋白不同酶解物的抗氧化特性,首先制备了不同的大豆球蛋白酶解物,然后对酶解物进行了表征(巯基含量、水解度、分子量等),并研究了还原前后不同酶解物的抗氧化活性(DPPH自由基清除能力、铁还原能力及二价铁螯合能力)以及抗氧化活性与巯基含量的关系,结果表明还原后的大豆球蛋白具有较好的酶解特性,还原后酶解物具有较高的巯基含量和抗氧化活性,还原后酶解物的DPPH自由基清除能力和铁还原能力与巯基含量具有显著相关性,二价铁螯合能力与巯基含量也呈现一定的相关性。     

氧化还原状态对肉仔鸡铁代谢利用的影响

对肉仔鸡给予含硫酸亚铁的补铁日粮,并在补铁日粮中添加不同水平的半胱胺。研究氧化还原状态对肉仔鸡体内铁代谢利用的影响。结果表明:试验组血红蛋白、血浆铁、肝脏铁含量升高,血浆总铁结合力降低。试验组的血浆丙二醛含量较对照组降低,血浆谷胱甘肽过氧化物酶活力、谷胱甘肽含量和总抗氧化能力显著升高(P<0.05)。这说明,半胱胺能够提高肉仔鸡机体的抗氧化性能,改变机体的氧化还原状态,促进肉仔鸡体内铁的代谢和利用,以80 mg/kg的添加水平最为显著。     

铁蛋白铁释放机理的研究进展

铁蛋白是一种广泛存在于生命体中的铁贮藏蛋白,具有调节机体铁代谢平衡和去除二价铁毒性的双重功能。缺铁严重影响着全球近一半人的健康,研究表明,铁蛋白具有良好的补铁活性而且安全、高效,能够取代具有毒副作用的传统补铁试剂。因此,寻求并开发以铁蛋白为原料的新型补铁功能食品已成为一种趋势。为了更科学地应用于实践和开发,对铁蛋白理化性质及其生物学功能的阐明显得颇为重要。目前,关于铁蛋白铁释放机理的研究分为体外和体内两个方面,体外机理涉及还原剂和螯合剂的共同作用,而体内机理主要涉及降解途径和酶介导的还原释放途径。综述了国内外有关铁蛋白铁释放机理的研究进展,以期为新型补铁功能食品的开发提供理论依据。     

黑豆皮中花青素与铁离子的相互作用

通过紫外-可见光谱、荧光光谱研究黑豆皮中花青素提取液与铁离子在不同pH值条件下的相互作用机制,并对花青素提取液对二价铁离子稳定性和三价铁离子溶解度的影响进行研究。结果表明：铁离子的引入改变了花青素的紫外-可见吸收光谱;荧光光谱表明铁离子对花青素具有荧光淬灭作用;且花青素提取液对二价铁离子有很好的抗氧化作用,对三价铁离子有良好的增溶效果。     

火麻仁粕酶解产物的抗氧化活性研究

采用Alcalase 2.4L FG酶解火麻仁粕,研究不同酶解条件下酶解物的抗氧化活性.结果表明,酶解5 h的产物抗氧化效果最好:酶解物对DPPH·、HO·的清除以及对二价铁离子螯合的EC50分别为1.36,0.62,1.15 mg/mL,虽然比传统抗氧化剂差,但发现在抑制油酸过氧化体系中从第5天开始酶解物对油酸的抑制效果优于α-生育酚,并且酶解物中游离抗氧化氨基酸高.     

缺铁性贫血与补铁剂研究概况

缺铁性贫血是世界范围内最普遍的营养素缺乏症之一,严重影响着人们的身体健康。铁摄入不足和过大消耗是造成缺铁性贫血的常见原因。因此,摄入足量的铁是预防和治疗缺铁性贫血的有效办法。科学工作者们一直致力于安全、有效的补铁剂的研究。目前补铁剂主要包括:以硫酸亚铁为代表的第一代补铁剂,以乳酸亚铁为代表的第二代补铁剂和近些年兴起的以大分子螯合铁为代表的第三代补铁剂。第三代补铁剂较第一、二代不仅具有吸收利用度好、副作用少、性质稳定等优点,而且其中大分子螯合剂还具有抗氧化、抑菌、免疫调节等生物活性,因而越来越受到人们的青睐,也成为了科研工作者的重点研究对象。本文围绕缺铁性贫血与人类健康、补铁剂研究历史、多糖铁复合物、多肽铁复合物以及富铁酵母等新型补铁剂的研究现状进行综述。     

黑姜抗氧化活性研究

研究了黑姜的体外抗氧化活性。黑姜是以新鲜的姜为原料,在一定条件下发酵而成。测定了黑姜与新鲜姜醇提物和水提物的抗氧化活性,其中包括清除DPPH自由基能力、清除ABTS自由基能力、清除OH自由基能力、二价铁离子还原能力。结果显示:与新鲜姜相比,黑姜的抗氧化活性增强,醇提物的活性要高于其水提物的活性。黑姜醇提物DPPH自由基清除率,其IC_(50)是0.12mg/mL,ABTS自由基清除率,其IC_(50)是0.04mg/mL,当样品浓度为0.5mg/mL时,OH自由基清除率为36.49%。二价铁离子还原力是鲜姜醇提的1.5倍。通过比较醇提物和水提物的抗氧化活性,得出样品的乙醇提取物的抗氧化活性要优于其水提取物的。     

抗坏血酸棕榈酸酯在不同油品中的抗氧化性能研究

研究了抗坏血酸棕榈酸酯在不同油旨中的抗氧化性能,研究结果表明：ＡＰ对不同油脂的抗氧化效果以猪油为最好,其次为棕榈油,花生油、菜籽油,大豆油,同时,对ＡＰ在不同油脂的Ｓｃｈａａｌ烘箱抗氧化性能,ＡＰ与不同抗氧化剂的性能比较,ＡＰ对油脂的烟点、溶解度和浊度进行了系统研究。     

铁和钙离子对分散红3B染色性能的影响

探讨了铁离子和钙离子对分散红3B染色性能的影响。结果表明:在染色过程中,钙离子的存在会导致染色织物的K/S值增加,色泽变艳;铁离子的存在会导致染色织物的K/S值下降,色泽萎暗,其中以二价铁离子对染色性能的影响更为明显;不同金属离子浓度对K/S值和颜色特征值的影响较小。     

不同溶剂核桃青皮提取物抗氧化性能研究

研究不同溶剂核桃青皮提取物的抗氧化性能。分别采用60%乙醇、蒸馏水、正丁醇和乙酸乙酯提取核桃青皮中的抗氧化活性物质。通过体外清除羟基自由基(·OH)、超氧自由基(O_2~-·)、亚硝酸盐(NO_2~-)及还原能力的测定评价核桃青皮提取物的抗氧化性能,并测定提取物中多酚含量。结果表明:不同溶剂核桃青皮提取物在四种不同的抗氧化体系中均表现出一定的抗氧化活性,且与提取物的质量浓度呈一定的量效关系,其中70%乙醇提取物的抗氧化性能最强,且其多酚含量高于其他提取物,说明核桃青皮提取物的抗氧化性能与其多酚含量呈正相关。     

Sensory characteristics and iron dialyzability of gluten-free bread fortified with iron

The objectives of the present study were (a) to produce gluten-free bread, fortified with iron (GFB-Fe), using selected iron compounds (ferric pyrophosphate, ferric pyrophosphate with emulsifiers, NaFeEDTA, electrolytic iron, ferrous gluconate, ferrous lactate and ferrous sulphate) (b) to test sensory characteristics of the GFB-Fe (feel-mouth texture, crumb colour, aroma and taste) (c) to compare iron dialyzability of various iron compounds in GFB-Fe. The most acceptable products were those fortified with ferric pyrophosphate with emulsifiers and ferric pyrophosphate. Ferrous dialyzable iron (ferrous iron with molecular weight lower than 8000 Da, an index for prediction of iron bioavailability) was measured under simulated gastrointestinal conditions. Ferrous dialyzable iron in GFB-Fe fortified with ferric pyrophosphate with emulsifiers, NaFeEDTA, ferrous bis-glycinate, ferrous gluconate or ferrous sulphate was higher than that in GFB-Fe fortified with electrolytic iron, ferrous lactate or ferric pyrophosphate (P < 0.05). These results are promising for the development of GFB-Fe products in the future.     

沙蚕多肽提取及功能研究

目的通过研究沙蚕酶解及其多肽产物的功能,提高沙蚕的利用率。方法采用碱性蛋白酶、胃蛋白酶、中性蛋白酶对沙蚕进行酶解,以水解度为评价指标,比较3种酶解产物的抗氧化活性、总还原力能力和降血糖功能。结果 3种酶中中性蛋白酶在6 h达到最高水解度37.8%。碱性蛋白酶酶解7 h的产物其亚铁离子螯合力最高,可达32.7%;DPPH自由基清除能力最高可达85.8%,为中性蛋白酶酶解6 h的产物;胃蛋白酶酶解6 h产物的总还原力最高;胃蛋白酶酶解3 h的酶解产物其DPP-4抑制率最高,可达52.9%。结论胃蛋白酶更适于沙蚕的酶解。酶解产物具有较理想的抗氧化及降血糖功能,为沙蚕多肽产品的开发奠定基础。     

米糠肽-铁锌螯合物制备工艺研究

目的 研究米糠蛋白制备米糠肽-铁锌螯合物的工艺。方法 以米糠蛋白为原料,优化米糠肽-铁锌螯合物制备工艺。以亚铁离子与锌离子的螯合率和水解度为评价指标,考察蛋白酶种类、反应物质量比、温度、时间及pH值对米糠酶解产物铁锌螯合率的影响。在单因素试验的基础上,结合JMP软件进行定制试验设计,确定米糠肽-铁锌螯合物的制备工艺。结果 碱性蛋白酶较适宜制备米糠肽-铁锌螯合物,其最佳螯合工艺条件为时间70 min、温度70 oC、反应物质量比3:1、pH 5.0;在此条件下,其产物亚铁离子螯合率达到38.29%、锌离子螯合率达到57.2%,与预测值接近。结论 本研究采用米糠肽同时螯合铁锌2种金属离子,不仅可以充分吸收米糠肽的营养成分,提高消化率,发挥其降血压、降血脂、抗氧化等功能特性,还可以同时补铁、补锌,对人体具有积极作用。     

Iron Availability from Soy, Meat and Soy/Meat Samples in Anemic Rats With and Without Prevention of Coprophagy

The biological availability of iron from samples of soy proteins (nontextured, extruded and spun), meat (chicken and beef) and spun soy/meat combination products was compared to ferrous sulfate using a hemoglobin regeneration bioassay. Compared to ferrous sulfate (55%) iron availability from the various soy proteins ranged from 29-57%, for the meat samples 32-39% and for soy/meat combination products 61-92%. There was no significant improvement in iron availability by fortification with ferrous sulfate or ascorbic acid. Prevention of coprophagy in the anemic rats during the bioassay using aluminum anal cups produced varying degrees of reduction in iron availability for various samples and this effect clearly needs further investigation.     

用铁离子快速测定肉制品中的亚硝酸钠

采用硫酸亚铁作还原剂,对与亚硝酸钠在酸性条件下反应,用硫氰酸钾作指示剂进行了研究,根据二价铁离子和三价铁离子浓度不同而显色不同的特点,提出了一种快速测定肉制品中亚硝酸钠的新方法。该法可精确测至0.1g,并与标准方法进行了比较,相对误差为10.43%。     

Fortification of soy sauce using various iron sources: sensory acceptability and shelf stability

BACKGROUND: Soy sauces are available in different types and grades, which allows them to reach consumers of all socioeconomic groups. Ferric sodium ethylenediaminetetraacetic acid (NaFeEDTA) has been used for iron fortification of soy sauces in some countries, however, its high cost may make it unattractive to policymakers and industry. OBJECTIVE: We evaluated the feasibility of using more economical iron sources for iron fortification, with soy sauce of various types and grades used as a vehicle. METHODS: Seven iron sources were tested for their feasibility for fortification of four types of soy sauce: naturally fermented in the traditional style, naturally fermented according to large-scale industrial formulas 1 and 5, and chemically hydrolyzed at 5 mg per serving (15 mL, per Thailand's food labeling regulations). Either citric acid or sodium citrate was added at 0.1% as a chelator. RESULTS: Five iron sources--ferrous sulfate, NaFeEDTA, ferric ammonium citrate, ferrous lactate, and ferrous gluconate--did not significantly affect the sensory qualities of the product over a period of 3 months (p > .05). Ferrous fumarate and ferrous bisglycinate caused unacceptable precipitation. Less than 3% of 260 and 306 commonly cooked foods out of 871 and 772 preparations using soy sauces fortified with NaFeEDTA and ferrous sulfate, respectively, were found to be different from normal with regard to sensory qualities. The cost of fortification was US 0.22 cents to US 3.28 cents per bottle (700 mL). CONCLUSIONS: Both naturally fermented and chemically hydrolyzed soy sauces could be fortified with all five iron sources. Ferrous sulfate is the most appropriate source because of its low cost and acceptable sensory characteristics. Soy sauce is a promising vehicle for iron fortification, however, the bioavailability of iron in the products examined here needs to be evaluated under normal use conditions.     

Influence of high dietary iron as ferrous carbonate and ferrous sulfate on iron metabolism in young calves

Twelve intact male Holstein calves averaging 90 kg and 12 wk of age were fed one of three dietary treatments for 28 d. The diets were A) control, B) control plus 1000 ppm iron as ferrous carbonate, and C) control plus 1000 ppm iron as ferrous sulfate monohydrate. Calves were dosed orally on d 15 of the treatment period with 1 mCi of iron-59. Neither source of added iron had a significant effect on weight gains, feed consumption, hemoglobin, packed cell volume, serum total iron, serum total iron-binding capacity, unbound iron-binding capacity, serum copper, tissue copper, fecal dry matter, or a consistent effect on fecal pH. The ferrous carbonate had no significant effect on stable zinc or stable iron in any tissue studied. Calves fed ferrous sulfate had higher average stable iron in most tissues and significantly more in the small intestine. Tissue zinc was lower in spleen and pancreas of ferrous sulfate-fed calves. Both sources of added iron sharply reduced iron-59 in serum, whole blood, and body tissues. The reduction was substantially greater in calves fed the ferrous sulfate iron. Iron in ferrous sulfate had a higher biological availability than that in the ferrous carbonate; however, bioavailability of the ferrous carbonate iron appeared to be substantial and considerably more than that noted in previous studies in which a different source of ferrous carbonate was used. The maximum safe level of dietary iron is materially influenced by the source of iron with a higher tolerance indicated for ferrous carbonated than ferrous sulfate monohydrate.     

Combating iodine and iron deficiencies through the double fortification of fish sauce,mixed fish sauce,and salt brine

Two iodine and seven iron compounds were tested for use in the fortification of pure fish sauce, mixed fish sauce, and salt brine for cooking as a means to combat iodine and iron deficiencies. Ferrous sulfate, sodium iron ethylenediaminetetraacetic acid, ferric ammonium citrate, and ferrous lactate were combined with potassium iodide with no effect on sensory quality. Product shelf-life testing revealed that no iron or iodine losses occurred during a three-month storage period. Although the color of most products darkened, the color was not significantly different from that of nonfortified products after two to three months. Sensory home-use tests revealed that the fortified products were acceptable to highly acceptable, with only 1.2% to 8.2% of the dishes cooked using the fortified products being reported as discolored. The cost of fortification was minimal, at 0.13 to 2.73 baht per bottle (750 ml) (42 baht = US$1). Consequently, these products show a potential for inclusion in national programs for the prevention of micronutrient deficiencies in Asian countries where fish sauce and its products are routinely consumed.     

我国含铁食品营养强化剂及食品添加剂标准的比较研究

目的比较我国含铁食品营养强化剂和食品添加剂标准差异。方法对GB 14880-2012《食品安全国家标准食品营养强化剂使用标准》和GB2760-2014《食品安全国家标准食品添加剂使用标准》中规定的含铁食品营养强化剂和食品添加剂的功能、使用范围、使用量以及各标准设置的理化指标、限量、标准发布时间等进行比较分析,对我国含铁食品营养强化剂和食品添加剂标准制定进行探讨。结果 GB14880-2012中规定了19种化合物可作为铁补充剂, GB 2760-2014中规定了7种含铁食品添加剂,目前已制定国家标准且现行有效的共14种,所有标准中均设置了理化指标,其中安全性项目主要是原料阴离子及重金属。重金属以铅和总砷的指标最有代表性。除了硫酸亚铁,所有亚铁类产品均设置了三价铁的相关项目控制产品质量。在重金属限量设置上,铅限量为1～10.0 mg/kg;总砷限量则在1.0～4.0 mg/kg之间。总汞限量,除了焦磷酸铁为3.0 mg/kg,其余均为1.0 mg/kg。结论结合我国国情,提出了我国食品营养强化剂和食品添加剂国家标准体系存在的主要问题。