金银花不同贮藏时期有效成分与抗氧化力的研究

采用生物化学分析法研究金银花不同贮藏时期的有效成分与抗氧化力。金银花采后常规贮藏1个月,其所含绿原酸和总黄酮下降显著;3个月后上述两种物质的含量为原来的50%～60%。其总抗氧化力下降趋势与之相同,且更为显著。金银花有效成分含量与总抗氧化力显著相关,金银花采后的贮藏情况对保持其抗氧化力非常重要。     

大豆异黄酮对糖尿病大鼠抗氧化能力的影响

目的：观察大豆异黄酮（soybean isoflavone,SIF）对糖尿病大鼠抗氧化能力的影响。方法：以四氧嘧啶（ALX）为诱导剂建立糖尿病动物模型,正常对照组（N）和糖尿病对照组（DC）以蒸馏水灌胃,大豆异黄酮组（SI）每日以100mg／kg·d的SIF溶液灌胃。实验6周后,分别测血清及肝脏中总抗氧化能力（T．AOC）、超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）和黄嘌呤氧化酶（XOD）活性及丙二醛（MDA）含量。结果SI组实验后血糖较实验前和DC组明显降低（p〈0．05）,DC组实验前血糖较实验后则明显升高（p〈0．05）。与DC组相比,SI组血清和肝脏GSH-Px和SOD抗氧化酶活性明显增强（p〈0．05）接近和超过正常水平,肝脏T．AOC能力明显高于DC和N组（p〈0．05）,而血清及肝脏MDA含量均低于DC组（p〈0．05）,血清XOD活性较DC组略有降低。结论：大豆异黄酮具有降血糖和增强机体抗氧化能力,其降糖机理与阻止胰腺B细胞和肝脏表面胰岛素受体进一步氧化损伤,修复其功能有关。     

辣椒碱对高脂血症大鼠抗氧化酶类活性影响研究

研究辣椒素类物质对高脂血症大鼠抗氧化酶类活性影响.长期低剂量摄取辣椒素类物质能显著提高高脂血症大鼠血清中抗氧化酶SOD和GSH-Px活性,同时显著降低血清中MDA的含量;但对肝中抗氧化酶SOD和GSH-Px活性影响不显著.提示长期低剂量摄取辣椒素类物质具有一定抗脂质氧化作用,可能对预防多种与脂质氧化有关的疾病如抗肿瘤,延缓衰老等均具有一定的作用.     

不同品质食用白酒对大鼠肝脏形态及其抗氧化能力的影响

为了观察不同品质食用白酒对大鼠肝脏形态及其抗氧化能力影响.将53 ％vol不同品质的白酒分为一号品酒、二号品酒、三号品酒和四号品酒,准备健康雄性SD(Sprague-Dawley)大鼠54只,随机分为9组:一号品酒高、低剂量组;二号品酒高、低剂量组;三号品酒高、低剂量组;四号品酒高、低剂量组以及生理盐水对照组.按低剂量(4 mL/kg·d)、高剂量(8mL/kg·d)分别给予SD大鼠灌胃2个月,最后一次灌胃后,禁食12h,取肝脏组织,制作肝脏切片,进行HE染色、苏丹染色和Masson染色,观察其组织形态学改变;比色法测肝脏抗氧化能力及其乙醇脱氢酶(Alcohol dehydrogenase,ADH).结果表明:①各实验组剂量依赖性地加重了肝脏细胞变性、脂肪变性和纤维增生,但以一号品酒大鼠肝细胞纤维化的变化较轻,四号品酒大鼠肝细胞变化严重;②各实验组大鼠的超氧化物歧化酶(Superoxide Dismutase,SOD)比对照组高(p＜0.05);一号品酒低剂量组的还原性谷胱甘肽(Glutathione,GSH)比对照组高(p＜0.05);二号品酒低剂量组的丙二醛(Malondialdehyde,MDA)值比正常组低(p＜0.05);③除二号品酒高剂量组、四号品酒高剂量组外的其余实验组大鼠肝脏乙醇脱氢酶(Alcohol dehydrogenase,ADH)值比对照组高(p＜0.05),一号品酒低剂量组、三号品酒低剂量组大鼠ADH值比二号品酒低剂量组、四号品酒低剂量组高(p＜0.05);三号品酒高剂量组大鼠ADH值比四号品酒高剂量组高(p＜0.05);同种品酒高、低剂量组之间无统计学差异(p＞0.05).由此推测,饮酒2个月,可引起肝脏形态学上的改变,肝脏的抗氧化能力和ADH酶活性增强,其变化的程度与酒的种类和剂量有关.     

银杏叶提取物对运动大鼠抗氧化效果的影响

以56只老年大鼠为实验对象,随机平均分为2大组,给药组和对照组。建立不同运动强度的老年大鼠跑台运动模型,每大组随机分为4小组,分别处于小强度运动(5 m/min),中强度运动(10 m/min),大强度运动(20 m/min)以及制动状态。探讨银杏叶提取物GBE对不同运动强度老年大鼠抗氧化效果的影响。通过检测脾脏,胸腺中相应MDA(丙二醛)的含量,SOD(超氧化物歧化酶)、CAT(过氧化氢酶)、GSH-Px(谷胱甘肽过氧化物酶)等酶活性,分析银杏叶提取物(GBE)对不同强度运动过程中对机体抗氧化效果的影响。结果表明:银杏叶提取物具有较好清除氧自由基的能力,能有效提高机体组织的抗氧化能力;适当的小强度和中强度的运动可有提高机体组织的抗氧化性,而在高强度状态下运动,机体组织的抗氧化性反而会降低。     

南瓜籽甾醇对SD大鼠体内抗氧化作用的影响

从南瓜籽油中提取的南瓜籽甾醇用于对SD大鼠体内抗氧化作用影响的研究。实验中将南瓜籽甾醇分为80、160、320 mg/(kg·d) 3种剂量灌胃SD大鼠,以不灌胃南瓜籽甾醇的SD大鼠为空白对照组。35 d后处死全部SD大鼠并取其血清和肝脏测定总抗氧化能力(T-AOC)水平、谷胱甘肽过氧化物酶(GSH-Px)和超氧化物歧化酶(SOD)活性、丙二醛(MDA)和血清中8-羟基脱氧鸟苷(8-OHdG)含量。结果表明:与空白对照组相比,3种剂量组SD大鼠血清和肝脏中的TAOC水平、GSH-Px和SOD活性升高,而血清和肝脏中MDA以及血清中8-OHd G含量降低。说明南瓜籽甾醇对SD大鼠体内抗氧化能力的增强具有一定的促进作用,并且这种作用存在一定的剂量依赖性。     

茶多酚对大鼠泌乳性能及抗氧化能力的影响

通过在不同能量条件下,研究茶多酚(TP)对泌乳期大鼠泌乳性能、血液生化指标及抗氧化能力的影响。选取40只SD孕鼠,随机分为4组,每组10个重复,每个重复1只。采用2×2拉丁方设计,分别饲喂:高能日粮(HE),低能日粮(LE),高能日粮+500mg茶多酚/kg饲料(HE-TP),低能日粮+500mg茶多酚/kg饲料(LE-TP),实验期40d。结果表明:添加TP显著提高大鼠的泌乳量及乳腺组织中催乳素(PRL)、雌激素(E2)水平(p<0.05),对采食量没有显著作用。在日粮中添加TP,均可显著降低HE和LE组大鼠血浆TG、GLU和UN水平(p<0.05)。添加TP,HE和LE组大鼠血浆T-AOC、CAT活力显著提高(p<0.05),SOD活力均提高但不显著(p>0.05),MDA水平显著降低(p<0.05)。结论:茶多酚通过提高母鼠的抗氧化能力,减少体内氧化产物,同时调节了泌乳激素水平从而提高了母鼠泌乳性能。     

南瓜籽油对大鼠血脂及抗氧化作用的影响

研究南瓜籽油对实验性高血脂大鼠的降血脂和抗氧化作用,采用高脂饮食构建高血脂大鼠模型,连续灌胃实验6周后,测定血清TG、TC水平及抗氧化指标。与高脂模型组相比,南瓜籽油各剂量组均有降低血清TG、TC及MDA水平和升高血清GSH-Px、SOD的作用,其中以中剂量组的降脂作用和抗氧化效果最好。中剂量组能显著降低血清TG和MDA水平的作用(P<0.05),降低血清TC和升高GSH-Px、SOD作用都达到极显著水平(P<0.01)。结果表明,南瓜籽油对大鼠有显著降低血脂和抗氧化作用。     

溶解度对大麦麦芽多酚含量和抗氧化力的影响

分析了35种不同溶解程度的大麦麦芽和相应协定糖化麦汁的总多酚含量和抗氧化力。相关性分析结果表明:麦芽的抗氧化力与其蛋白质含量呈高度显著的负相关性(r=-0.500,P<0.01),而与麦芽的库尔巴哈值、浸出物含量和游离总多酚含量之间呈显著的正相关性;麦汁的总多酚、抗氧化力和花色苷含量均与麦芽的蛋白质含量呈高度显著的负相关性,而与麦芽的库值、浸出物含量、游离总多酚和抗氧化力之间呈高度显著的正相关性。研究认为,大麦品种在决定成品麦芽和麦汁的抗氧化特性的同时,制麦工艺和麦芽的溶解度对其抗氧化力也有非常重要的影响。本文为啤酒生产中大麦麦芽品质的综合评价提供了新的参考。     

大豆异黄酮对青年雌性大鼠的抗氧化作用研究

目的:研究大豆异黄酮对青年雌性大鼠的抗氧化作用并检验其安全性。方法:选用2月龄青年雌性大鼠50只,按体重随机分成5组,每组10只,分别为空白对照组(基础饲料);低(L-SI)、中(M-SI)、高剂量组(H-SI),其大豆异黄酮含量分别为100、200、300 mg/kg bw;雌激素组(EC,己烯雌酚0.5 mg/kg),实验周期为7周。观察各组大鼠实验前、后血清中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、丙二醛(MDA)和谷胱甘肽过氧化物酶(GSH-PX)等活力变化以及子宫雌激素受体(ER-α)含量的变化,并做病理组织学检查,检验其安全性。结果:大豆异黄酮可显著提高各剂量组SOD活力(p0.05);低、中剂量组CAT活力升高显著,有显著性差异(p0.05),而在高剂量组没有显著差异;显著降低大鼠MDA含量;对GSH-PX活性的作用不显著。大豆异黄酮可上调大鼠子宫ER-α含量。高剂量组大鼠卵巢发生病理变化。结论:大豆异黄酮可增强青年雌性大鼠的抗氧化能力,其在100~200 mg/kg bw剂量范围对大鼠无不良影响;而当剂量为300mg/kg bw时,对青年雌性大鼠的卵巢产生负面作用。     

Antioxidant capacities and total phenolic contents of 62 fruits

In order to supply new information on the antioxidant function of selected fruits for nutritionists and the general public, antioxidant activities and total phenolic contents of 62 fruits were evaluated using ferric reducing antioxidant power (FRAP) and Trolox equivalent antioxidant capacity (TEAC) assays as well as the Folin–Ciocalteu method, respectively. The correlations between the FRAP value and the TEAC value as well as total phenolic content were also assessed. The results showed that different fruits had diverse antioxidant capacities and the variation was very large, and seven fruits, Chinese date, pomegranate, guava, sweetsop, persimmon, Chinese wampee and plum, possessed the highest antioxidant capacities and total phenolic contents among tested fruits, and could be important dietary sources of natural antioxidants for prevention of diseases caused by oxidative stress.     

Bergamot: A source of natural antioxidants for functionalized fruit juices

Bergamot is a common Italian citrus fruit, cultivated almost exclusively to produce essential oils; the juice is considered a waste product, which represents a serious environmental and economic problem for the industries. The aim of this study was to re-evaluate bergamot juice through its chemical characterization and its use to enrich and fortify fruit juices. To investigate this, apples and apricots were used for the laboratory-scale production of fruit juice, following both the traditional industrial recipe and those with the addition of bergamot juice at 10% or 20%, together with or in order to replace the synthetic additives normally used in the industrial process (ascorbic acid and citric acid). The ascorbic acid content and the antioxidant activity were measured during the different steps of juice production and after storage at 37 °C for 15 days to evaluate juice shelf-life. Apricot and apple juices fortified with bergamot juice showed a significant increase in their antioxidant properties and a decreased reduction in ascorbic acid content after the typical production steps. All of the results obtained support the hypothesis that the addition of bergamot juice to juices preserves their ascorbic acid content from thermal degradation and contributes to enhance the antioxidant activity, ensuring a product much richer in antioxidants and ascorbic acid. A preliminary consumer test encouraged the production of bergamot fortified fruit juices. Finally, this is the first time that isorhoifolin and rutin have been detected in bergamot juice.     

Grape juice obtained using steam extraction and other small‐scale extraction methods: phenolic content,antioxidant capacity and stability during storage

Grape juices made using small‐scale production techniques are widely consumed. The extraction procedures employed to produce them, however, can affect bioactive compounds and antioxidant activity in the final product. In this study, juices prepared using four extraction methods (steam, extractor, juicer and blender) were evaluated for soluble and hydrolysable polyphenol content, total anthocyanin content, antioxidant capacity, physicochemical characteristics and colour. Acceptance of steam‐extracted juices and their stability during storage were also evaluated. Steam extraction resulted in a higher soluble phenolic (1073 ± 58 mg gallic acid L^?1) and anthocyanin content (138 ± 22 mg cyanidin L^?1), as well as a higher antioxidant capacity when compared to juices prepared using other methods. Although steam‐extracted juice remained microbiologically stable during 24 months of storage, changes in phytochemical compounds and antioxidant capacity did occur. Our results indicate that steam‐extracted grape juices have high commercial potential.     

Vitamin C,vitamin A,phenolic compounds and total antioxidant capacity of new fruit juice and skim milk mixture beverages marketed in Spain

The growing interest in new functional foods with special characteristics and health properties has led to the development of new beverages based on fruit juice–skim milk mixtures. The proliferation of ready-to-drink beverages has caused the market to focus its interest on these products. Commercial conventionally pasteurized or sterilized beverages based on a mixture of fruit juice and skim milk were evaluated nutritionally for their concentrations of vitamin C, vitamin A and phenolic compounds and their total antioxidant capacity, taking the influence of physicochemical parameters into account. The main contribution to the total antioxidant capacity (TEAC, trolox equivalent antioxidant capacity) was provided by vitamin C, followed by phenolic compounds, in accordance with a mathematical equation obtained from the data: TEAC = −0.184 + 0.009 ∗ [vitamin A] + 0.011 ∗ [phenolic compounds] + 0.058 ∗ [vitamin C]. The R-squared value was 86.88%. Citrus fruits, such as lemons or oranges, were the fruits associated with the greatest antioxidant capacity in the samples analysed.     

Electrochemical determination of antioxidant capacity of fruit tea infusions

Cyclic voltammograms (CV) taken to 800 mV at a scan rate 100 mV s⁻¹ were used to quantify electrochemical properties of antioxidants present in 10 fruit tea infusions as well as to deduce antioxidant capacity from the Q₆₀₀ parameter (charge passed to 600 mV). A pronounced anodic current peak observed at 440 mV in all analysed fruit teas indicated that ortho-dihydroxy-phenol and gallate groups are the major contributors to the antioxidant capacity of investigated teas. Antioxidant composite index (ACI) was determined for each tea employing antioxidant capacity values from previous spectrophotometric determinations as well as the Q₆₀₀ parameter derived from CV. A ranking of the most potent teas was obtained: the fruit tea containing a large portion of rose hip fruit exhibited the highest ACI and a CV with the most pronounced anodic current peak at 440 mV pointing to the presence of ortho-dihydroxy-phenol and gallate group containing compounds. Strong positive correlation was established between antioxidant capacities deduced from CVs with those previously determined using established spectrophotometric techniques (FRAP, ABTS and DPPH assays).     

果汁冷冻浓缩过程中冰晶形成规律的研究

本研究测定了橙汁和菠萝汁的冰点曲线,并以此探讨在果汁冷冻浓缩时水分冻结率的变化规律。结果表明,果汁在开始冻结的温度附近结冰率变化最大;以后逐渐减慢。橙汁和菠萝汁的最大冰晶生成区分别是-0.8～-7.9℃和-0.7～-6.7℃。冷却介质温度越低,冰晶的生长速度越快,但最终冰晶尺寸越小。当介质温度为-10℃左右时,可获得较大的冰晶尺寸。本文也研究了搅拌作用及果汁预处理因素对冰晶生长的影响。     

酶法提取树莓汁的研究

本试验以澳洲红、早红、美国22三个品种树莓为原料,通过不同的酶处理方法来制原果汁,优选适于制汁的品种和酶处理方法。