Hepatoprotective and antioxidant activity of anthocyanins in black rice bran on carbon tetrachloride-induced liver injury in mice

The benefits of anthocyanin-rich black rice bran extract (ARBE) on the liver of carbon tetrachloride (CCl₄)-intoxicated mice was investigated. Based on the in vivo experiment, the effect of cyanidin-3-glucoside (Cy-3-G) and peonidin-3-glucoside (Pn-3-G), the predominant anthocyanins in ARBE, on CCl₄ insulted hepatocytes L-02 was further evaluated. Mice treated with ARBE for 7 weeks by oral administration showed reduced aminotransferase activities in serum, accompanied by enhanced superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity, while tiobarbituric acid reactive substances (TBARS), and 8-hydroxy-2′-deoxyguanosine (8-OHdG) levels were significantly decreased compared to CCl₄-intoxicated model group. Histopathological observation showed ARBE administration alleviated the pathological changes in livers of CCl₄-intoxicated mice. Similarly, preincubation of L-02 cells with Cy-3-G or Pn-3-G significantly alleviated CCl₄-induced injury dose-dependently, exhibited higher cell viability, decreased aminotransferase activity and enhanced cellular antioxidant status. Furthermore, Cy-3-G showed much stronger hepatoprotective activity than Pn-3-G at the same concentration. HPLC analysis showed that Cy-3-G accounted for more than 88% of total anthocyanins in ARBE. These results indicate that ARBE is significantly beneficial to liver health, and that Cy-3-G is the predominant anthocyanin in ARBE exerting this effect. The antioxidant activity of anthocyanins is an important mechanism by which ARBE exerts hepatic health benefit.     

米曲霉发酵米糠制取米糠多肽及其抗氧化活性研究

利用米曲霉对米糠进行发酵,研究了接种量、培养时间、培养温度和pH对发酵过程中蛋白酶活力和米糠多肽含量的影响,并利用响应面法对发酵条件进行了优化;分析了米糠多肽的分子量分布和抗氧化活性。结果表明,米曲霉发酵米糠的最佳条件为:接种量为14.6%,培养时间为48.6h,培养温度为29.5℃,pH为5.5,多肽含量达到128.4mg/g。发酵米糠多肽的分子量主要集中在500~800u之间,大约占75.6%,并且具有较强的抗氧化活性,对羟基自由基和DPPH自由基清除率最高分别达到86.2%和69.8%。      

微波加热钝化黑米糠过氧化物酶

采用微波加热法,以过氧化物酶残余活力为指标,通过单因素和正交实验得出微波钝化黑米糠过氧化物酶的最佳条件为:黑米糠含水量26%、加热时间105s、加热功率900W,该优化条件下过氧化物酶残余活力为0.5%。旨在为黑米糠工业化开发提供基础科学依据。      

酶法水解脱脂米糠蛋白抗氧化性质研究

以脱脂米糠为原料,采用碱性蛋白酶、酸性蛋白酶和中性蛋白酶酶解制备米糠蛋白,并将制备酶解液与抗坏血酸在超氧阴离子自由基(O2-.)清除率、羟自由基(.OH)清除率、H2O2清除能力及还原能力等方面进行比较,研究米糠蛋白抗氧化活性。结果表明,米糠蛋白具有较强抗氧化活性,虽效果不如抗坏血酸;但对超氧阴离子自由基(O2-.)(最高为98.41%)、羟自由基(.OH)(最高达97.04%)及H2O2均有不同程度清除作用,并具有一定还原能力;且抗氧化能力与添加量存在一定量效关系,其中还出现有促氧化特殊现象。     

米糠贮藏时间对米糠可溶性膳食纤维抗氧化性质的影响

以新鲜米糠为原料贮藏0、1、3、5、10 d得到不同酸败程度的米糠,稳定化和脱脂后制备米糠可溶性膳食纤维,研究米糠贮藏时间对米糠可溶性膳食纤维抗氧化性质的影响。结果表明:随着新鲜米糠贮藏时间的延长,米糠可溶性膳食纤维的还原能力、金属离子螯合能力和清除ABTS~+·、DPPH·、·OH、O_2~-·能力均先上升后下降;米糠可溶性膳食纤维还原能力、金属离子螯合能力和清除ABTS~+·、DPPH·、·OH在新鲜米糠贮藏5 d时达到最大值,分别为0.943(OD_(700))、35.16%、32.28%、73.51%和13.83%,米糠可溶性膳食纤维清除O_2~-·能力在新鲜米糠贮藏1 d达到最大值,为60.58%。     

Effects of rice bran fermented with Lactobacillus plantarum on palatability,volatile profiles,and antioxidant activity of brown rice noodles

Brown rice noodles (RN) are typical whole-grain products with health benefits. This study investigated the effects of rice bran fermented with Lactobacillus plantarum on palatability, volatile profiles, and antioxidant activity of brown RN. Three kinds of RN, including RN, brown RN (BRN), and bran fermented RN (BFRN), were involved in this study. The results indicated that bran fermentation reduced the cooking loss of BFRN and improved the elongation and the sensory attributes of brown RN. After fermentation, aldehydes were significantly decreased while alcohols increased, and more pleasant flavours were shown in BFRN. Fermentation increased the content of free phenolics and decreased the content of bound phenolics. Among the four major phenolics detected in this study, ferulic acid was the most abundant one in all three RN samples. The DPPH radical scavenging activity and the ferric reducing antioxidant power of free phenolics in BFRN increased significantly compared to BRN. This study proved that rice bran fermentation is an effective approach to improve palatability, enrich the flavour as well as enhance the antioxidant activity of brown RN, which may facilitate the development of processing technology for brown RN.     

混菌固态发酵米糠产谷维素的工艺及抗氧化活性评估

目的:提高米糠谷维素的得率。方法:以米糠为研究对象,经单因素试验筛选出酿酒酵母和枯草芽孢杆菌作为固态发酵菌种,以谷维素含量为指标,通过单因素试验结合Box-Behnken响应面法优化混菌固态发酵工艺,采用DPPH自由基和ABTS自由基清除试验对发酵提取物抗氧化活性进行评价,并通过扫描电镜(SEM)分析混菌固态发酵法富集谷维素的原理。结果:在酿酒酵母和枯草芽孢杆菌混菌处理下,米糠谷维素最优发酵工艺为发酵时间44 h,发酵温度34℃,接种量10%,含水量40%,在此条件下谷维素含量为(7.816±0.038) mg/g,是未发酵米糠谷维素含量的1.9倍。混菌固态发酵法制备的提取物具有较强的DPPH自由基和ABTS自由基清除活性,其IC₅₀值分别为(0.220±0.007),(0.409±0.014) mg/mL,与未发酵米糠相比,其IC₅₀值分别降低了28.6%和39.7%。SEM分析结果显示,混菌固态发酵后米糠组织表面油脂更少,结构疏松多孔,更加有利于米糠中谷维素的释放。结论:米糠经混菌固态发酵后,谷维素含量和抗氧化活性均得到显著提高。     

米糠酒的发酵工艺优化研究

以米糠为原料,通过单因素和正交试验对米糠酒的发酵工艺条件进行优化。结果表明,米糠酒的最佳发酵工艺：料水比1∶2（g∶mL）,酵母菌接种量0.4%,发酵温度34 ℃,发酵时间12 d。在此条件下,米糠酒的酒精度为10.3%vol,可溶性固形物含量为1.8 °Be',米糠酒酒体清澈透亮有光泽,具有米糠和酒的香味,口感醇香浓郁。     

米糠固态发酵工艺优化及其氨基酸变化

对米糠进行固态发酵,研究其蛋白、脂肪、灰分和总糖含量的变化规律,以期找到一种有效深度开发米糠资源的方法。结果表明:蛋白和灰分含量相比于发酵前明显增加,脂肪和总糖含量随着发酵时间的延长逐渐降低。以真蛋白含量为响应值,对固态发酵条件进行响应面辅助优化,确定最佳发酵条件为温度37℃,时间102h,水分含量60%,初始pH 5.5,接种量20 mL/100 g,发酵米糠的真蛋白含量19.65%,比原米糠提高了41.88%。此外,对米糠的氨基酸组成进行分析,蛋氨酸和苏氨酸占总氨基酸含量分别提高了73.92%和22.99%。     

脱脂米抗氧化肽的分离纯化与研究

通过碱性蛋白酶酶解脱脂米糠蛋白制得脱脂米糠抗氧化肽（DRBAP）,用DEAE-52、SephadexG-15纯化DRBAP,薄层层析鉴定其纯度。通过亚油酸体系中抗氧化能力、自由基捕获能力、金属离子螯合力等不同的实验体系研究其纯化组分的体外抗氧化活性,同时分析了其氨基酸组分和分子量分布情况。结果表明,分离纯化得到抗氧化活性较高的组分G4,较纯化前的DRBAP其对铁离子的螯合率提高了近11%,对DPPH自由基、·OH、O2-·清除率依次提高了20%、9%、16%,在亚油酸体系中吸光值下降了0.7,其主要氨基酸成分为Asp、Glu、Leu、Phe、Arg、Pro,相对分子质量小于1000u的比例达到90.83%,分子量小于500u的达到14.38%。      

米糠淀粉酶酶解及在乳酸发酵中的应用研究

介绍了以膨化米糠为原料,利用淀粉酶对其进行酶解,针对加酶量、酶解时间、温度、作用的pH值对米糠的酶解进行研究,以多糖得率为指标的试验。采用正交试验确定最佳的酶解效果,结果表明:温度60℃,pH为5.0,酶用量100 IU.g-1,时间2 h为最适宜酶解条件。在此条件下,利用酶解液在乳酸发酵中对培养基酸度和菌种生长情况进行研究,结果表明,米糠酶解液能够促进乳酸发酵液中菌种的生长,提高发酵液的酸度。     

Anthocyanin content and antioxidant capacity in bran extracts of some Thai black rice varieties

This study investigated both the anthocyanin content and the antioxidant capacity of a set of genetically related glutinous and nonglutinous Thai black rice varieties. The ethanol/water extracts of the brans of these black rice varieties showed relatively potent antioxidant activities compared with those of tocopherol. These antioxidant activities were determined by thiocyanate, H₂O₂‐scavenging chemiluminescence (XYZ), Cu⁺⁺/bathocuproine colorimetry (PAO) and 1,1‐diphenyl‐2‐picrylhydrazyl radical‐scavenging assay. The structural identification and quantification of the black rice anthocyanins performed by high‐performance liquid chromatography coupled with electrospray ionisation and tandem mass spectrometry found cyanidin‐3‐O‐glucoside and peonidin‐3‐O‐glucoside as the major anthocyanins in the ranges of 16.01–34.40 and 2.43–7.36 μg mL^?1, respectively. The comparative study in terms of quantity of these phytochemicals and antioxidant capacity of the black rice bran extracts suggested the contribution of overall phenolic components rather than that of the particular anthocyanin pigments.     

纯黑米醪糟发酵工艺优化

以黑米为原料,通过单因素试验研究黑米醪糟发酵过程中的5个主要影响因素,浸米时间、浸米温度、酒曲添加量、发酵温度以及发酵时间对黑米醪糟发酵的影响。以感官评分为响应值,采用响应面试验对黑米醪糟发酵工艺进行优化。结果表明,最适发酵条件为浸米时间1.0h、浸米温度63℃、酒曲添加量4.4%、发酵时间42h、发酵温度31℃。所得产品的主要理化指标为总糖236.9g/L、总酸4.3g/L、酒精度1.39g/100mL。该发酵条件下酿造出的黑米醪糟,呈紫红色,酿液透明有光泽,味浓甜,爽口,酒香味浓郁,口感软糯,具有黑米醪糟独特的风格和较高的营养价值。     

米糠增值转化应用的研究进展

米糠是一种营养丰富、应用前景广阔的高附加值资源,实现米糠的增值转化对提高我国粮食加工水平具有重要意义。从米糠的性质、稳定化、活性因子、在发酵及食品工业中的应用等方面综述了米糠增值转化应用的研究进展。     

酶法协同超声波提取米糠多糖及其抗氧化活性研究

研究了酶法协同超声波处理对米糠多糖提取的影响,利用响应面法对米糠多糖提取工艺进行了优化,并探讨了米糠多糖的抗氧化活性。结果表明,纤维素酶与中性蛋白酶复配使用(质量比1∶1)以及超声波处理有利于米糠多糖的提取。提取米糠多糖的最佳条件为:复合酶加量3.1 mg/m L,酶解时间2 h,超声功率198 W,超声时间20 min,料液比1∶30,提取时间3.2 h,提取温度60℃;在此条件下米糠多糖得率达到5.3%。米糠多糖具有较强的还原力和一定的抗油脂氧化活性,对DPPH自由基、羟基自由基均表现出较好的清除能力。     

20种黑米的总酚含量与抗氧化活性

采用超声波辅助乙醇法提取20种黑米中的总酚,福林-酚法测定总酚含量,铁氰化钾法、铁还原抗氧化能力（FRAP）法、1,1-二苯基-2-三硝基苯肼（DPPH）法测定抗氧化活性。对黑米的总酚含量和不同抗氧化方法测定的抗氧化活性开展相关性分析。结果表明,黑米的总酚含量及抗氧化活性因品种不同存在显著差异（p<0.05）,总酚含量介于（2.305±0.035）^4.842±0.030mg/g之间,得到五种高总酚含量、高抗氧化活性黑米品种。相关性分析发现,黑米总酚抗氧化能力与总酚含量之间呈现极显著的正相关（R2>0.900,p<0.01）。本研究为全面开展黑米品种资源的选育及综合开发利用提供了参考价值和科学依据。      

Characteristics of Aspergillus niger xylanases produced on rice husk and wheat bran in submerged culture and solid‐state fermentation for an applicability proposal

Xylanolytic rich filtrates were obtained by A. niger sp in both submerged and solid‐state culture using rice husk or wheat bran as the only carbon source. Filtrates obtained on rice husk showed the highest activities (~6500 and 5200 U g^?1, respectively). Independent of carbon source, these filtrates were very stable in an acidic pH range (4–7) and mild temperatures, with high half‐life time values (more than 7 h at 50 °C) in the corresponding inactivation kinetic models. Also the effect of different metallic ions and denaturing substances was verified finding that these enzymes are not metaloproteins, and metals as Hg²⁺ and Pb²⁺ caused the greatest loss of xylanolytic activity (not higher than 30%). Xylanases produced by this A. niger strain showed important features that make them potential candidates for applications on human and livestock food industries.     

超声-微波协同提取富硒米糠蛋白的工艺优化及其抗氧化活性评价

为解决富硒米糠蛋白提取率低、提取时间长及提取后功能特性下降等问题,以脱脂富硒米糠粉为原料,通过单因素试验和正交试验对超声-微波协同提取富硒米糠蛋白的工艺进行优化,通过与超声辅助法、微波辅助法和碱提法比较,探究该提取方法对富硒米糠蛋白的提取效果、抗氧化活性以及提取后米糠颗粒表面形貌变化的影响。结果表明,超声-微波协同提取富硒米糠蛋白的最佳工艺条件为超声功率600 W、微波功率500 W、提取时间20 min、料液比1∶40,在此条件下富硒米糠蛋白的提取率为86.94%,与超声辅助法、微波辅助法、碱提法相比富硒米糠蛋白提取率分别提高了40.96%、48.00%、53.50%,并且提取的富硒米糠蛋白抗氧化能力和硒含量更高。扫描电镜结果显示,超声-微波协同提取后米糠颗粒表面疏松卷曲,完整皮层结构消失,说明超声-微波协同能通过强烈破坏米糠颗粒结构增加富硒米糠蛋白的提取率,并提高其抗氧化活性。综上,超声-微波协同提取技术能够促进富硒米糠蛋白的提取并提高其抗氧化活性。     

纳豆芽孢杆菌/短乳杆菌混合发酵米糠的响应面工艺优化

以稳定米糠为主要基质,豆渣为营养因子,纳豆芽孢杆菌和保加利亚乳杆、嗜热链球菌、植物乳杆茵、瑞士乳杆菌、短乳杆菌为试验菌株,运用固态发酵技术,采用响应曲面法对益生茵混合发酵米糠的固体发酵工艺进行优化分析。试验结果表明:短乳杆菌最适于与纳豆芽孢杆菌混合发酵米糠,经响应面优化后最优发酵条件如下:米糠54%、豆渣6%、水40%、接种量10%、纳豆芽孢杆菌与短乳杆菌接种比例为1:1、温度34℃,先接入纳豆芽孢杆菌发酵3 d后再接入短乳杆菌发酵2 d。发酵后米糠中纳豆激酶产生量较其他混合菌种发酵方式明显提高,其中纳豆芽孢杆菌活茵数达到6.8×10~9cfu/g短乳杆菌活茵数4.5×10~9 cfu/g。