Effect of different rumen-inert fatty acids supplemented with a dietary antioxidant on performance and antioxidative status of early-lactation cows

The objective of the study was to evaluate the effect of diets supplemented with fatty acids of different degrees of saturation, in the absence or presence of an antioxidant (AOX; Agrado Plus, Novus International Inc., St. Charles, MO), on dairy cow lactation performance. Calcium salts of long-chain fatty acids were supplemented as a source of lower saturation fatty acid, and a palm acid product was supplemented as the higher saturation fatty acid source. Sixty early-lactation Chinese Holstein cows (100 ± 23 d in milk) were randomly allocated to 4 dietary treatments in a 2 × 2 factorial design: (1) lower saturation fatty acid (LS), (2) LS and AOX, (3) higher saturation fatty acid (HS), and (4) HS and AOX. The Ca salts of long-chain fatty acids and palm acid product were supplied at 1.8 and 1.5% on a dry matter basis, respectively, to form isoenergetic diets. The AOX was added at 0.025% in the ration. The experiment lasted 9 wk, including 1 wk for adaptation. Lactation performance was recorded and milk was sampled and analyzed weekly. Blood samples were taken from the coccygeal vein to determine metabolism parameters on d 16, 36, and 56 during the experiment. Neither fatty acid type nor AOX supplementation showed a significant effect on dry matter intake during the study. Milk yield was lower in the LS-fed cows compared with the cows fed HS. Milk fat and milk protein concentrations were not affected by fatty acid type or AOX supplementation. Adding AOX increased the yield of milk in the LS-fed cows, but did not affect those fed HS. Activity of plasma superoxide dismutase was significantly lower, plasma glucose tended to be lower, and plasma malondialdehyde was higher in the LS-fed animals compared with those fed HS. Addition of AOX decreased both plasma nonesterified fatty acids and hydrogen peroxide contents and increased total antioxidant capacity across the fatty acid types. Plasma β-hydroxybutyrate was not affected by fatty acid type or AOX treatment. Cows fed LS had higher cis-9 C_18:1 and trans-10, cis-12 C_18:2 in milk at the expense of C_18:0, whereas AOX addition increased milk cis-9 C_18:1 at the expense of milk C_12:0, C_16:0, and trans-10, cis-12 C_18:2. It is inferred that feeding LS resulted in inferior lactation performance, whereas addition of antioxidant partially alleviated these negative effects.     

Assessment of endogenous antioxidative compounds and antioxidant activities of lager beers

BACKGROUND: Flavour stability is increasingly becoming the limiting factor in the shelf life of beer. Increasing the antioxidant activity of beer itself could suppress the rate of oxidative reaction and improve the flavour stability of beer. This report describes the levels of phenolic compounds, melanoidins and sulfur dioxide, and antioxidant activities of 40 lager beers. The relationships between antioxidative compounds and antioxidant activity were elucidated by multivariate analysis techniques. RESULTS: The results showed that the total phenolic content and the melanoidins content correlated well (P < 0.05) with antioxidant activity, while there was no significant correlation (P > 0.05) between total sulfur dioxide content and antioxidant activity. Satisfactory discrimination among beer samples with significantly different antioxidant activity was achieved by principal component analysis. Results from stepwise linear regression further demonstrated that different antioxidative components responsible for antioxidant activity were dependent on the assay used. The phenolic compound group is by far the most antioxidative compounds in beer and total phenolic content, melanoidins and sulfur dioxide together made a 22–68% contribution to the antioxidant activities of beers. CONCLUSION: Therefore, it might be an efficient means for brewers to increase total phenolic content during brewing for improvement in flavour stability of the final beer. © 2012 Society of Chemical Industry     

辣椒籽提取物抗氧化活性研究

用不同溶剂提取辣椒籽中的抗氧化物质,从还原能力、抗脂质体氧化和对Fenton体系产生的羟自由基的清除效果等方面对辣椒籽提取物的抗氧化活性进行了试验研究和评价。结果表明:辣椒籽提取物具有较强的还原能力,对脂质体氧化、Fenton反应产生的羟自由基均具有抑制作用或消除作用,优于同浓度的Vc和VE的效果或基本相当,这表明辣椒籽提取物是一种优良的天然抗氧化剂和自由基消除剂,而且不同溶剂的辣椒籽提取物的抗氧化作用效果不同,其中脱脂甲醇提取物>甲醇提取物>脱脂水提取物>Vc>石油醚提取物>VE。     

Evaluation of antioxidative activity of vegetable extracts in linoleic acid emulsion and phospholipid bilayers

The antioxidative effects of vegetable extracts were evaluated using linoleic acid emulsion and liposomal phospholipid suspension systems. First, the antioxidative activities of water, ethanol and 2% metaphosphoric acid extracts of the vegetables were investigated by measuring the rate of oxygen consumption in the peroxidation of linoleic acid initiated by a radical generator, 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH), with a Clark electrode in the absence of metal chelators. Ethanol extracts of moroheiya and perilla exhibited the highest antioxidative activities. Without metal chelators, 12 ethanol extracts and one water extract acted as prooxidants, and this phenomenon could be attributed to the prooxidant action of ascorbic acid in the presence of free transition metal ions. Next, peroxyl radical-scavenging activities of vegetable extracts were examined by adding a metal chelator, diethylenetriaminepentaacetic acid (DTPA), to the linoleic acid emulsion system. The results were compared with their antioxidative activities in phospholipid bilayers by measuring the inhibition of lipid peroxidation in large unilamellar vesicles composed of egg yolk phosphatidylcholine (PC). A good correlation was observed between the antioxidative activities obtained from these two systems. The antioxidative activities in the liposomal phospholipid suspension system correlated with total contents of ascorbic acid and polyphenols in vegetable extracts. © 1999 Society of Chemical Industry     

Antioxidative activities of grape (Vitis vinifera) seed extracts obtained from different varieties grown in Turkey

In this study, total phenolic contents and antioxidant activities of grape seed extracts obtained from twelve different grape seeds from common varieties grown in Turkey were determined. Grape seeds were extracted with 70% acetone and extraction yield of grape seed were calculated. The total phenolic content of grape seed extracts were determined by the Folin‐Ciocalteu procedure and ranged from 33 945 to 58 730 mg per 100 g extract as gallic acid equivalent. Antioxidant activities of grape seed extracts with two different free radical scavenging methods, ABTS [2,2/‐azinobis (3‐ethylbenzothiazoneline‐6‐sulfonic acid)] and DPPH (2,2‐diphenyl‐picrylhydrazyl) assays, using Trolox equivalent as standards, were investigated. Grape seed extracts exhibited antioxidant activities 2.46–4.14 and 3.55–5.76 [Trolox equivalent antioxidant capacities (TEAC) mg^?1 extracts] in ABTS and DPPH assays, respectively. Compared with varieties, Muskule extracts exhibited the lowest total phenolic content, TEAC_ABTS and TEAC_DPPH value while Narince extracts had the highest total phenolic content and TEAC_DPPH value, and Alphonse Lavalleé had the highest TEAC_ABTS value. Total phenolic content showed that there is a significant correlation with TEAC_DPPH (r = 0.7974, P ≤ 0.001) and TEAC_ABTS values (r = 0.4860, P ≤ 0.05).     

玻璃海鞘不同极性提取物体外抗氧化活性的研究

通过对DPPH自由基、脂质过氧化及总抗氧化能力的测定,从而探求玻璃海鞘不同极性提取物的抗氧化能力。结果表明,玻璃海鞘不同极性提取物均具有一定的抗氧化能力,但均低于VC的抗氧化能力。用IC50衡量清除自由基的能力,正丁醇萃取物清除DPPH自由基能力最强,为(1218.03±4.79)mg/L,其次是石油醚萃取物,乙酸乙酯萃取物最弱;乙酸乙酯萃取物对脂质过氧化的抑制作用最强,为(2325.17±3.80)mg/L,石油醚萃取物次之,正丁醇萃取物最弱;在一定浓度下,总抗氧化能力从强到弱排列顺序依次为石油醚萃取物>乙酸乙酯萃取物>正丁醇萃取物。     

Effects of feeding lutein on production performance,antioxidative status,and milk quality of high-yielding dairy cows

This experiment was conducted to determine the influences of supplementing different levels of an additive containing lutein in the diet of Chinese Holstein lactating cows on production performance, antioxidative plasma metabolites, and milk quality. This study was performed on 60 multiparous Holstein dairy cows in peak lactation. The cows were randomly allocated to 1 of 4 homogeneous treatments, with lutein preparation (extracted from marigolds; effective lutein content was 2%) added at levels of 0, 100, 150, and 200 g/d per head, with the actual available amounts being 0, 2, 3, and 4 g of lutein/d per head, respectively. The experiment lasted for 13 wk, with the first week for adaptation. Milk yield and milk compositions were recorded weekly, and milk concentrations of lutein, dry matter intake, and antioxidative blood index were analyzed in the first, fourth, seventh, and thirteenth week of the study. The results showed that adding lutein in the diet had no effect on dry matter intake compared with the control group; however, it slowed down the trend of decline in milk yield, and had a linear incremental effect on milk yield with increasing concentration of lutein. Dietary lutein tended to quadratically increase the percentage of milk fat, and linearly increased milk lactose concentration, with the highest value when treated at 200 g of lutein preparation/d per head, and decreased somatic cell count, with the lowest values when treated with 150 and 200 g of lutein preparation/d per head. The concentration of lutein in milk linearly increased with the incorporation of the additive, with a value of 0.59, 0.70, 1.20, and 1.50 μg/100 mL when treated with 0, 100, 150, and 200 g/d, respectively. Total plasma antioxidant capacity tended to linearly increase in cows fed lutein preparation, whereas plasma superoxide dismutase and glutathione peroxidase activities did not differ significantly. In conclusion, addition of lutein in the diet could improve the production performance and health status of dairy cows.     

番茄籽蛋白的提取工艺

经脱油的番茄籽采用碱提酸沉工艺,通过正交和优化试验提取番茄籽蛋白,得到了番茄籽蛋白提取的最佳工艺:pH8.5,50℃,搅拌时间30min,料液比1:50(w/v)下碱提番茄籽蛋白,经pH4.5盐酸沉淀,再复溶至pH8.5进行冷冻干燥,番茄籽蛋白总提取率为43.31%,纯度为82.06%。     

提取溶剂对生姜抗氧化性能影响的研究

本文采用几种溶剂并结合微波技术浸提生姜中的抗氧化物质;研究了不同溶剂提取物对猪油的抗氧化效果,其抗氧化性能大小排序为:乙醇提取物> 乙醇微波提取物> 乙酸乙酯提取物> 正己烷提取物> 丙酮提取物。并进一步探讨了提取物浓度与抗氧化性能的关系。     

莲藕多糖的提取及生物活性的研究

对莲藕水溶性多糖的提取工艺及体外生物活性进行了探索。采用正交实验设计,得到了莲藕多糖的最佳提取条件为料液比为16∶、浸提温度为90℃、浸提时间为6h,采用体外实验研究莲藕多糖对超氧阴离子、羟自由基清除作用以及对H2O2诱导的红细胞氧化溶血的抑制作用。结果表明:莲藕多糖对超氧阴离子的清除作用较弱,对羟自由基具有很强的清除作用,并能有效抑制H2O2诱导的红细胞氧化溶血。     

三种不同方法提取葵花油的性质比较

本文旨在研究不同提取方法（水酶法;溶剂法;冷榨法）对葵花油的脂肪酸组成、理化性质、酚类物质、生育酚含量、抗氧化活性和氧化稳定性的影响。采用了清除DPPH自由基、抑制β-胡萝卜素-亚油酸乳化体系褪色实验和清除ABTS+·阳离子方法评价葵花油的抗氧化活性,并通过等温DSC测定了三种葵花油的氧化稳定性。结果表明:提取方法对葵花油脂肪酸组成的影响不显著（p<0.05）。与溶剂法和水酶法相比,冷榨法葵花油表现出较优质的产品特性。溶剂法葵花油的总酚含量（TPC,0.29 mg/g）、邻苯二酚含量（ODC,0.45 mmol/kg）和总生育酚含量（TTC,1090.81 mg/kg）最高,并且具有最强的DPPH自由基(IC₅₀,3.54 mg/m L)、ABTS+·阳离子清除能力（TEAC,652.33μmol/L）以及最强的抑制β-胡萝卜素褪色能力（C%,45.93%）。不同提取方法对葵花油的氧化稳定性影响显著（p<0.05）,氧化稳定性依次为:溶剂法>水酶法>冷榨法。      

秦皮不同溶剂提取物总酚含量及抗氧化活性

分别以水、加0.5%纤维素酶水和50%乙醇溶液为提取剂,超声辅助提取秦皮,采用Folin-Ci-ocalteu法测定提取物中总酚含量,同时利用清除DPPH.和羟自由基(.OH)法评价秦皮提取物的抗氧化活性。结果表明,不同溶剂水、50%乙醇和加0.5%纤维素酶水的秦皮提取物中总酚含量分别41.68mg/g、49.32mg/g和51.51mg/g;对DPPH.的半清除率(IC50)分别为0.29mL、0.22mL和0.17mL;对.OH的半清除率(IC50)分别为2.4mL、2.0mL和1.3mL。秦皮不同溶剂提取物都具有较强的抗氧化活性,其大小顺序为:加酶水提物>醇提物>水提物,抗氧化活性与提取物中总酚含量成正相关。     

固相分散萃取-液相色谱法测定番茄酱中2-萘酚

采用固相分散萃取-高效液相色谱法测定番茄酱中的2-萘酚。无水硫酸钠作分散剂、乙腈作萃取剂,考察了2,4-二氯苯氧乙酸存在时的干扰情况。色谱条件:TOSOHC18色谱柱;甲醇-水(体积比50∶50)为流动相;流速:1.0 mL/min;检测波长:230 nm。2-萘酚在0.005μg/mL～2.00μg/mL范围内线性良好,方法检出限为1μg/g,平均回收率为75.0%,相对标准偏差为3.0%。     

Antioxidant properties of tomato juice as affected by heating

The changes in the overall antioxidant properties of tomato juice samples and model solutions as a consequence of heat treatments were studied. The antioxidant properties were evaluated both through the measurement of the chain breaking and the oxygen scavenging activities. While a decrease in the antioxidant potential was found for short heat treatments, a recovery of these properties was measured by prolonging heating times. Results suggested that the initial reduction in the overall antioxidant activity can be attributed not only to the thermal degradation of naturally occurring antioxidants but also to the formation of early Maillard reaction products (MRP) with pro‐oxidant properties. The gain in antioxidant activity coincided with the formation of brown MRP. © 1999 Society of Chemical Industry     

四种干燥方法生产番茄粉的品质特性研究

通过对喷雾干燥、热风干燥、真空干燥及真空冷冻干燥4种方法制成番茄粉的番茄红素含量、粉体特性等指标的分析及对比研究,对4种加工工艺生产的番茄粉的品质特性进行了评价,真空冷冻干燥法制成番茄粉的品质最好,喷雾干燥法从工艺适应性与经济效益多方面权衡该法应是首选。     

不同方法提取绞股蓝总皂苷的比较研究

以常规乙醇回流法、酶法及微生物发酵法提取绞股蓝总皂苷,通过总皂苷含量、单体皂苷组分、抗氧化活性三方面对不同提取方法进行比较研究。结果显示,复合酶法提取所得绞股蓝总皂苷含量达7.69%,比常规回流法相对提高了31%,但对皂苷组分转化未见显著效果。微生物发酵提取破壁效果最佳,提取物中绞股蓝总皂苷含量达8.34%,比回流提取法所得含量相对提高了42.1%;经发酵处理后,绞股蓝总皂苷中活性更强的次级苷组分如绞股蓝皂苷V-AH（人参皂苷Rg3）等含量增加,对DPPH·清除的IC50值相比常规法由1.544 mg/m L降至0.562 mg/m L,对Fe³⁺还原力的V_C当量抗氧化能力AEAC值提高至（236.299±12.785）mg V_C/g固形物,显示出该方法的优越性。      

祁州漏芦不同溶剂提取物抗氧化活性的比较研究

研究祁州漏芦的体外抗氧化活性。以高铁还原力法检测总抗氧化能力,以水杨酸法检测羟自由基(.OH)清除率,以硫代巴比妥酸(TBA)法测定H2O2和Fe2+诱导的肝匀浆丙二醛(MDA)生成量。结果表明,漏芦不同溶剂提取物均具有较强的总抗氧化能力和清除羟自由基能力,可抑制H2O2和Fe2+诱导的肝匀浆脂质过氧化的发生,且呈剂量依赖性。其中,漏芦正丁醇萃取物(RUBF)的抗氧化活性高于水萃取物(RUAF)。因此,祁州漏芦具有体外抗氧化活性。     

甘草中天然抗氧化剂的提取工艺研究

研究了用乙醇提取甘草时提取条件对甘草提取物抗氧化性的影响,通过单因素试验确定了提取时间、提取温度、溶剂浓度和液料比的大致范围,用RSM(响应面分析法)设计了正交试验,试验结果表明:提取时间为9h、提取温度为51.34℃、液料比为8.03时的甘草无水乙醇提取物的抗氧化性最好。     

生姜黄酮的提取及其抗氧化活性的测定

研究了从生姜中提取黄酮的工艺，结果表明：以80％的乙醇水溶液为溶剂,固液比为1：2，在80℃下回流3h，提取率最高。并在不同条件下探索了提取液的稳定性和抗氧化活性。