迷迭香水溶性和脂溶性抗氧化剂的分离

研究了石油醚萃取法、水溶解法、浓缩法分离迷迭香水溶性和脂溶性抗氧化剂,对抗氧化剂的得率及总酚含量的影响。结果表明,不同的分离方法对两种抗氧化剂的得率及总酚含量的影响不大。本文同时应用HPLC法测定了3种方法分离所得的抗氧化剂中迷迭香酸、鼠尾草酸和鼠尾草酚的含量。由于水溶解法所得的抗氧化剂中3种活性成分的含量高于石油醚萃取法和浓缩法,综合考虑,水溶解法是一种较好的分离方法。     

几种天然抗氧化剂对牡丹籽油氧化稳定性的影响

采用Schaal烘箱耐热试验法,以人工合成抗氧化剂二叔丁基羟基甲苯、丁基羟基茴香醚和特丁基对苯二酚等为阳性对照,研究茶多酚、苹果多酚、葡萄多酚、野葡萄多酚、牡丹籽多酚、生育酚、脂溶性迷迭香提取物和水溶性迷迭香提取物等8种天然抗氧化剂及2种增效剂(维生素C和柠檬酸)对牡丹籽油氧化稳定性的影响。研究以过氧化值为评价指标。结果表明,在国家允许添加量范围内,几种天然抗氧化剂均能提高牡丹籽油的氧化稳定性,但单独使用的效果要弱于人工合成抗氧化剂特丁基对苯二酚。其中脂溶性迷迭香提取物抗氧化效果较为理想,与合成抗氧化剂特丁基对苯二酚效果接近。维生素C与柠檬酸是抗氧化剂的良好增效剂,协同抗氧化作用显著,且维生素C的效果优于柠檬酸。复合抗氧化剂的抗氧化效果优于同等质量浓度的单一抗氧化剂,复合添加0.01%脂溶性迷迭香+0.01%茶多酚+0.02%维生素C、0.01%牡丹籽多酚+0.01%苹果多酚+0.02%维生素C和0.01%脂溶性迷迭香+0.01%茶多酚+0.02%柠檬酸均能显著减缓牡丹籽油的氧化速度,可使牡丹籽油的贮藏时间明显延长。     

迷迭香脂溶性抗氧化剂提取工艺的优化研究

以经不同方法预处理(蒸馏法去精油和水煮法去精油)后的迷迭香叶为原料,无添加食用油为提取剂,通过单因素试验考察提取温度、料液比、提取时间及提取次数对脂溶性抗氧化剂(鼠尾草酸+鼠尾草酚)得率的影响。在单因素试验的基础上,采用响应面法对提取工艺条件进一步优化。结果表明:水煮法去精油的原料迷迭香脂溶性抗氧化剂的最优提取条件为提取温度61℃、料液比1∶11、提取时间61 min、提取次数5次,在此条件下脂溶性抗氧化剂得率为2.860 1%;蒸馏法去精油的原料迷迭香脂溶性抗氧化剂的最优提取条件为提取温度71℃、料液比1∶11、提取时间81min、提取次数4次,在此条件下脂溶性抗氧化剂得率为3.801 3%。对比分析表明,蒸馏法去精油的迷迭香脂溶性抗氧化剂得率高于水煮法去精油的。     

脂溶性迷迭香抗氧化剂对油脂的抗氧化作用和生鲜猪肉的保鲜效果

以氧化诱导时间为评价指标,研究了脂溶性迷迭香抗氧化剂对6种食用油的抗氧化作用,同时将脂溶性迷迭香抗氧化剂应用到生鲜猪肉中,研究其对生鲜猪肉的保鲜效果。结果表明:脂溶性迷迭香抗氧化剂对鱼油、亚麻籽油、葵花籽油、米糠油、山茶油和椰子油的抗氧化效果呈现剂量效应关系,0.70%脂溶性迷迭香抗氧化剂对6种食用油的抗氧化最好,强于0.02%BHT;脂溶性迷迭香抗氧化剂对椰子油的抗氧化效果最佳。将脂溶性迷迭香抗氧化剂添加到生鲜猪肉中,能有效减缓生鲜猪肉在储藏过程中TBA值的上升和pH的下降,抑制生鲜猪肉中微生物的生长,延缓其氧化和腐败变质。     

响应曲面法优化迷迭香抗氧化剂提取工艺

以香草迷迭香为原料,进行超临界CO2萃取迷迭香抗氧化剂的工艺优化,并利用响应曲面法进行试验设计、工艺参数优选。结果表明:超临界萃取迷迭香抗氧化剂的最佳工艺条件为萃取压力26.98MPa、萃取时间2.28h、夹带剂用量0.48mL/g;实际所得抗氧化剂中总酚含量达12.70mg/g。该方法简便、可靠,可用于迷迭香抗氧化剂的提取。     

澄清黄秋葵汁储藏过程中理化性质的变化

选取壳聚糖作为澄清剂制作一批澄清黄秋葵汁并将其分别放置于4℃、室温(20℃)和37℃避光储藏。在不同储藏时间分别随机取样,测定秋葵汁中总酚含量、蛋白含量、褐变指数、悬浮稳定性和透光率。结果表明,在不同温度下,秋葵汁在储藏过程中透光率、悬浮稳定性、可溶性蛋白、总酚含量都随着时间的延长逐渐降低,而褐变指数随着时间的延长逐渐升高。随着储藏温度升高,悬浮稳定性和可溶性蛋白降低,而褐变指数和总酚含量升高。     

几种抗氧化剂对生姜油稳定性的研究

比较不同抗氧化剂加入生姜油稳定性的研究.生姜油中分别加入TBHQ、脂溶性茶多酚、维生素E和迷迭香提取物(鼠尾草酸油)四种抗氧化剂,以姜辣素含量损失率为评价指标,通过对110℃下抗氧化剂添加量的实验、70℃下加速稳定性试验和长期抗氧化试验筛选,结果确定效果最佳的抗氧化剂为天然抗氧化剂产品脂溶性茶多酚,最适添加量为0.4％...     

响应面法优化迷迭香脂溶性提取物脱色工艺

旨在为迷迭香脂溶性提取物在食用油保鲜方面的应用提供参考,以玉米油提取的迷迭香脂溶性提取物(可作为抗氧化剂)为原料,对其进行脱色处理,以脱色率为指标,通过单因素试验和响应面试验优化脱色工艺条件,并采用高效液相色谱法测定脱色前后迷迭香脂溶性提取物中脂溶性抗氧化成分(鼠尾草酸和鼠尾草酚)的含量。结果表明：与活性白土及活性白土与活性炭复配(质量比1∶1、1∶2、2∶1)脱色剂相比,活性炭对迷迭香脂溶性提取物的脱色效果最好,最佳脱色工艺为活性炭添加量2.1%、脱色温度50℃、脱色时间59 min,在此条件下脱色率为(75.02±0.37)%;脱色前后迷迭香脂溶性提取物中脂溶性抗氧化成分含量分别为4.065 5%和3.883 6%。综上,优化条件下迷迭香脂溶性提取物的脱色效果较好,且脱色对其脂溶性抗氧化成分含量影响较小。     

山西老陈醋抗氧化物质含量及其分析

采用分光光度法对山西老陈醋酿造过程中不同生产阶段及不同存放时间山西老陈醋的总酚、总黄酮含量及DPPH自由基清除率进行了测定.并对不同生产阶段总酚、总黄酮含量及DPPH自由基清除率变化进行了分析,得出:山西老陈醋生产过程中总酚含量、总黄酮含量及DPPH自由基清除作用在醋酸发酵阶段开始增加,熏醅时达到最高.抗氧化活性的变化与多酚变化具有相关性.瓶装成品老陈醋随着存放时间的延长,抗氧化物质含量有所下降.     

迷迭香脂溶性抗氧化剂在花生油中的复配筛选及货架期模型构建

将迷迭香(鼠尾草酸、鼠尾草酚、熊果酸)与维生素C(VC)棕榈酸酯、茶多酚棕榈酸酯、槲皮素、5%β-胡萝卜素等4种天然脂溶性抗氧化剂在花生油中进行多元复配，对其氧化稳定性研究筛选出最佳复配组合；在25、35、45、55℃条件下构建氧化动力学模型，对花生油货架期进行预测。结果表明：迷迭香脂溶性提取物+VC棕榈酸酯+茶多酚棕榈酸酯+槲皮素四元复配抑制花生油氧化效果最佳。通过建立过氧化值随时间和温度变化的氧化动力学模型结合Arrhenius方程得到lnk=-4 065.8/T+10.706,在25℃条件下，预测添加四元复配抗氧化剂花生油货架寿命为3 533.76 h,实测值为3 050.88 h,与空白相比货架期延长1.95倍。     

Oxidative stability of butter with added phenolics from Lamiaceae herbs and in vitro evaluation of potential cytotoxicity of rosemary (Rosmarinus officinalis L.) extract

This study evaluated the oxidative stability of butter with added phenolics from Lamiaceae herbs. Initially antioxidant activity of crude rosemary, oregano, sage, thyme and marjoram extracts were screened through methods of inhibition of the 1,1‐Diphenyl‐2‐picrylhydrazyl (DPPH) radical, malondialdehyde (MDA) quantification and ferric reducing antioxidant power test. The alcoholic extract of rosemary showed the highest antioxidant activity in both assays for DPPH radical inhibition and MDA quantification. The alcoholic rosemary extract showed no cytotoxicity when assayed using MTT [3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide] reduction method and had dose‐dependent cytoprotective activity at 50 and 250 μg mL^?1. These results suggest that the use of rosemary as natural antioxidant is safe in the concentrations tested. The highest oxidative stability of butter with added alcoholic rosemary extract at temperatures of 60 and 110 °C was obtained with the concentration of 400 mg of phenolic compounds per kg of butter and was reflected at the lowest formation of degraded peroxides from lipids.     

天然抗氧化剂对亚麻籽甘油二酯油氧化稳定性的影响

为提高亚麻籽甘油二酯油的氧化稳定性,研究了抗坏血酸棕榈酸酯、迷迭香提取物和维生素E及其组合对亚麻籽甘油二酯油的抗氧化作用。以氧化诱导时间为响应值,在单因素实验基础上,通过响应面分析确定最优的抗氧化剂组合。考察了优化的抗氧化剂组合对亚麻籽甘油二酯油高温加热时反式脂肪酸含量的影响。结果表明：相较于单一的维生素E、迷迭香提取物和抗坏血酸棕榈酸酯,三者组合能显著提高亚麻籽甘油二酯油的氧化稳定性;最优抗氧化剂组合为抗坏血酸棕榈酸酯添加量84 mg/kg、迷迭香提取物添加量405 mg/kg、维生素E添加量1 808 mg/kg,在此条件下亚麻籽甘油二酯油的氧化诱导时间为11.13 h,是空白对照的6.79倍;该抗氧化剂组合能抑制油中反式脂肪酸的生成。天然抗氧化剂绿色、安全,可有效提高亚麻籽甘油二酯油的氧化稳定性。     

Total phenolics and antioxidants profiles of commonly consumed edible flowers in China

Edible flowers are referred to the non-toxic flowers that can be consumed by human beings for their additional nutritional or medical properties. These flowers are rich source of natural antioxidants, thus exert specific positive health effects on chronic diseases and act as a potential function food. This research paper is focused on the determination of total phenolic content (TPC), total flavonoids content (TFC), and antioxidant capacities of different kinds of edible flowers in China and compared systematically. Sixty-five flower samples were collected from parks in Guangzhou and also purchased from Qingping Market. TPC, TFC, and three anti-oxidative assays (DPPH free radical scavenging activity, ABTS radical scavenging activity, and Ferric reducing antioxidant capacity (FRAP) assay) were conducted. Different flowers presented diverse range of antioxidant capacities, phenolic contents, and flavonoid contents. A high correlation between TPC and antioxidant activity (as accessed using three different methods) was reported. However, a low relationship was observed between TFC value and antioxidant capacities. This study revealed that five Rosa species exhibited strong antioxidant capacities among other samples, and these can be used as potential functional foods to counterbalance the effect of reactive oxygen species (ROS) and oxidative stress.     

Effects of γ-irradiation on antioxidant and antimicrobial activities and color of <Emphasis Type="Italic">Ecklonia cava</Emphasis>

Ecklonia cava (EC) was irradiated with γ-rays at doses of 3, 7, and 20 kGy. The extraction yields, total polyphenol content (TPC), DPPH radical scavenging activity, antimicrobial activity, and color of the EC extracts were assessed. The results showed that irradiation caused an increase in the extraction yields of ethanol and water. TPC was found to be significantly increased when EC powder was subjected to irradiation, followed by ethanol and water extraction. However, DPPH radical scavenging and antimicrobial activities were stable under all irradiation conditions. In the heat and pH stability tests, the DPPH radical scavenging activities of EC ethanol extracts were not influenced by irradiation. Irradiation caused an increase in the lightness and redness of EC extracts and decreased the yellowness. In conclusion, γ-irradiation increased the extraction yield and TPC and brightened the color, while maintaining the antioxidant and antimicrobial activities.     

Thermoxidative stability of soybean oil by natural extracted antioxidants from rosemary (Rosmarinus officinalis L.)

This study aimed to evaluate the effects of rosemary extract, grown in Iran, on thermoxidative stability of soybean oil. Rosemary extract was added to soybean oil at a concentration of 3000 mg/kg and then heated at 180°C for 20 h. The oxidative stability index, total polar compounds, tocopherol content, and fatty acid profile were measured at intervals of 0, 10, and 20 h. The results compared with synthetic antioxidant tert-butyl hydroquinone at a concentration of 50 mg/kg. Rosemary extract could lead to higher oxidative stability index, lower polar compounds, more retention of tocopherols and the greatest amount of polyunsaturated fatty acids in soybean oil after 20 h of thermoxidation process. The tert-butyl hydroquinone showed weaker antioxidant activity than rosemary extract and there was no synergistic effect between them.     

Influence of heating on the polyphenolic content and antioxidant activity of grape seed flour

Abstract: The production of grape seed flour (GSF) from a waste product generated during winemaking, is of interest in product development applications due to its potential health benefits. However, before GSF can used in baking as a source of additional antioxidants, research on its heat stability is required. The overall objective of this study was to assess changes in phenolic content and antioxidant activity of GSF during heating. Merlot GSF was heated at 5 temperatures (120 to 240 °C) for 0 to 90 min. At each time/temperature combination, total phenolic content (TPC), total flavanoid content (TFC), Trolox equivalent antioxidant capacity (TEAC), 2,2 diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging, and ferric ion reducing antioxidant power (FRAP) of the extracts were determined. Specific polyphenolic compounds, including catechin, gallocatechin, epicatechin, and gallic acid were also measured. Results showed that when Merlot GSF was heated to ≥180 °C, significant decreases in the TPC and antioxidant activity, measured using FRAP, DPPH, and TEAC, were observed. Longer heating times also caused a reduction in antioxidant capability. Catechin and epicatechin content decreased with increasing heating temperature while gallocatechin and gallic acid content increased. Both catechin and epicatechin content had strong positive correlations (r > 0.91) with TPC and TFC, as well with FRAP and TEAC, suggesting that the GSF antioxidant activity is related to the presence of these particular compounds. Overall, while a decrease in antioxidant content was observed during heating, this occurred at higher baking temperatures. Thus GSF may be suitable for use as an ingredient in baked goods to bolster antioxidant content. Practical Application: In order for Merlot grape seed flour (GSF) to be used in baking as a source of additional antioxidant compounds, the impact of heating on the polyphenolic compounds in the GSF needed to be examined. Thermal treatment of Merlot GSF caused significant decreases in the TPC, antioxidant power, and specific polyphenolic compounds when heated ≥180 °C. Thus while antioxidant content decreased with higher heating temperatures, this occurred at higher baking temperatures. Thus, GSF may be suitable for use as an ingredient in baked goods to bolster antioxidant content.     

Antioxidant activity, total phenolics content, anthocyanin, and color stability of isotonic model beverages colored with Andes berry (Rubus glaucus Benth) anthocyanin powder

The stability of anthocyanin (ACN) freeze-dried powders from Andes berry (Rubus glaucus Benth) as affected by storage, addition of maltodextrin as a carrier agent, and illumination was evaluated in isotonic model beverages. The ethanolic ACN extract was freeze dried with and without maltodextrin DE 20. Isotonic model beverages were colored with freeze-dried ACN powder (FDA), freeze-dried ACN powder with maltodextrin (MFDA), and red nr 40. Beverages were stored in the dark and under the effect of illumination. Half life of the ACNs, changes in color, total phenolics content (TPC), and antioxidant activity were analyzed for 71 d. Addition of maltodextrin and absence of light stabilized the color of beverages and improved ACN and TPC stability during storage. The antioxidant activity of the beverages was higher when they were colored with MFDA and highly correlated with ACN content. There was no correlation between antioxidant activity and TPC. It is concluded that addition of maltodextrin DE 20 as a carrier agent during freeze-drying improves the color and stability of nutraceutical antioxidants present in Andes berry extract. This suggests a protective enclosing of ACNs within a maltodextrin matrix with a resulting powder that could serve as a supplement or additive to naturally color and to enhance the antioxidant capacity of isotonic beverages.     

Antioxidant and antibacterial activity of leaves of Etlingera species (Zingiberaceae) in Peninsular Malaysia

Methanolic extracts from fresh leaves of five Etlingera species were screened for total phenolic content (TPC), antioxidant activity (AOA), and antibacterial activity. Analysis of TPC was done using the Folin–Ciocalteu method. Evaluations of AOA included 1,1-diphenyl-2-picrylhydrazyl free radical-scavenging ability, ferric-reducing antioxidant power (FRAP), ferrous-ion chelating (FIC) ability, and β-carotene bleaching (BCB) activity. Antibacterial activity was screened using the disc-diffusion method. Highest TPC, ascorbic acid equivalent antioxidant capacity (AEAC), and FRAP were found in leaves of E. elatior and E. rubrostriata. Leaves of E. maingayi, with the lowest TPC, AEAC, and FRAP, had the highest FIC ability and BCB activity. Ranking of TPC and AOA of different plant parts of E. elatior was in the order: leaves > inflorescences > rhizomes. Leaves of highland populations of Etlingera species displayed higher values of TPC and AEAC than those of lowland counterparts. Leaves of Etlingera species exhibited antibacterial activity against Gram-positive but not Gram-negative bacteria.     

Effect of dietary rosemary and α-tocopheryl acetate on the oxidative stability of raw and cooked pork following oxidized linseed oil administration

The effect of a 2% dietary administration to pigs of oxidized linseed oil (targeted level of 150mEq.O(2)/kg oil after heating at 50°C and exposure to air for 3-4 days following addition of 10ppm CuSO(4)), either or not in combination with antioxidants, on the oxidative stability of raw and cooked pork during illuminated chill storage was assessed. The antioxidant treatments were: 40ppm α-tocopheryl acetate, 40ppm rosemary extract, 40ppm rosemary extract+2ppm gallic acid, and 40ppm α-tocopheryl acetate+40ppm rosemary extract. A total of 20ppm of α-tocopheryl acetate (ATA) was added to all diets in order to meet the physiological requirement of the animals. The antioxidant treatments did not exert any effect on colour and protein oxidation. Lipid oxidation was only decreased by dietary ATA when comparing the ATA supplemented groups combined versus a control treatment group for raw but not for cooked meat. This was due to a higher content of α-tocopherol in the meat and subcutaneous fat. The lipid oxidation results suggested a lack of antioxidant effect for the rosemary extract. No evidence for a synergistic effect of the antioxidant combinations was observed.     

Evaluation of the antioxidant properties and oxidative stability of Pecorino cheese made from the raw milk of ewes fed Rosmarinus officinalis L. leaves

The aim of this work was to study the effect of rosemary leaf dietary supplementation on the antioxidant activities and total phenolic content of Pecorino cheese. Three hundred and twenty‐four sheep were randomly assigned to two dietary groups, which received a standard diet based on lucerne hay and concentrate (400 g per day). The concentrate of the rosemary supplemented group contained 2.50% dried rosemary leaves. The trial lasted 7 weeks. Cheesemaking was performed 3, 5 and 7 weeks from the start of the trial. The Pecorino cheese antioxidant activity was modified by the diet. Rosemary supplementation increased the total phenolic content, enhanced the antioxidant properties and decreased the lipid oxidation of cheese. A slight decrease in flavour was detected in cheeses after 7 weeks of rosemary administration.