土家药食资源藤茶黄酮类化合物体内外抗氧化活性研究

目的:系统研究土家药食资源藤茶黄酮类化合物的体内外抗氧化活性,为藤茶药食资源及有效组分黄酮类化合物的保健开发提供科学依据。方法:分别采用羟基自由基清除法、DPPH自由基清除法、β-胡萝卜素-亚油酸测定抗氧化活性法、硫代巴比妥酸法4种体外抗氧化活性实验系统评价药物的体外抗氧化活性。同时,建立D-半乳糖诱导小鼠氧化损伤模型,观察药物体内的抗氧化作用。结果:藤茶黄酮类化合物对羟基自由基(IC_(50)=30.977 mg/mL)和DPPH自由基有明显的清除作用(IC_(50)=22.524μg/mL),对β-胡萝卜素-亚油酸氧化体系有明显的抑制作用(IC_(50)=0.323mg/mL),对硫代巴比妥酸法所测定的抗氧化率也明显升高(IC_(50)=102.171 mg/mL)。同时,药物对小鼠氧化损伤模型,能明显或部分降低小鼠血清和肝脏中MDA的活性或含量,升高SOD、GSH和GSH-Px的活性。结论:上述结果表明藤茶黄酮类化合物具有确切的体内外抗氧化活性。     

验证芝麻酚的抗氧化性质

现代技术研究表明，芝麻中含有多种具有抗氧化作用的物质。芝麻经过正己烷脱脂、乙醇提取等方法处理，可以得到含有芝麻酚的提取物。然后利用2-硫代巴比妥酸检测提取物的抗氧化能力。     

共轭亚油酸氧化稳定性及其抗氧化性的研究

对由红花籽油制取的共轭亚油酸(CLA)和红花籽油组成脂肪酸(SFA)进行氧化稳定性比较。过氧化值和硫代巴比妥酸反应物的测定结果表明，在实验条件下，CLA的氧化稳定性高于SFA，但CLA并不是一种抗氧化剂。米糠油对于CLA的抗氧化效果与BHT相似。     

加工工艺对香榧油脂氧化和抗氧化活性的影响

研究了加工过程香榧酸价、碘价、过氧化值、p-茴香胺值、硫代巴比妥酸还原值和DPPH自由基清除能力的变化趋势,从而了解加工工艺对香榧油脂氧化和抗氧化活性的影响。结果表明,香榧在加工过程中发生了油脂的氧化酸败,其中第1次炒制和调味液浸泡后酸价和过氧化值分别较前道工序增加269.16%、56.07%和80.22%、73.17%;香榧抗氧化能力降低,表现为第1次炒制后硫代巴比妥酸还原值为前道工序的171.18%,而DPPH自由基清除能力下降至75.41%。因此,第1次炒制和调味液浸泡两道工序是影响香榧品质的重要环节。     

两种抗氧化剂对米糠油氧化稳定性的比较研究

<正>本研究通过Schaal烘箱氧化法(60℃),以过氧化值(POV值)、酸价(AV值)、p-茴香胺值(p-AV值)和硫代巴比妥酸值(TBARS值)为评价指标来检测不同抗氧化剂对米糠油的氧化稳定性影响。研究发现抗坏血酸棕榈酸酯(AP)和二丁基羟基甲苯(BHT)都能在一定程度上提高米糠油的抗氧化能力,降低油脂的氧化程度,延缓米糠油的酸败过程,其中AP的抗氧化效果明显优于BHT。本研究表明,在米糠油的实际生产中添加0.015%的AP即可明显改善其抗氧化效能,延缓油     

厚朴抗氧化作用研究

分别用ＤＰＰＨ法,硫代巴比妥酸法及Ｎａ２Ｓ２Ｏ３滴定法测定了厚朴提取物的抗氧作用。结果表明：不同溶剂厚朴提取物对ＤＰＰＨ自由基均有清除作用,其中以乙醇提取物清除能力最强。厚朴乙醇提取物对亚油酸、猪油的脂质过氧化有良好的阻断作用,其抗氧化作用随提取物用量的增加而逐渐增强。对猪油的抗氧化作用以６０％乙醇提取的活性最强     

硫代巴比妥酸光度法测定山梨酸的研究

本文探讨了用硫代巴比妥酸光度法测定山梨酸含量时,测定条件(包括最大吸收波长,氧化剂K_2Cr_2O_7的适宜用量、氧化时间,氧化温度,显色剂硫代巴比妥酸的适宜用量、显色时间,稳定时间等)的选择和确定,以及乙醇对测定的影响。实验结果表现,山梨酸含量在标准曲线线性范围内时加入0.05%K_2Cr_2O_7溶液4.0ml,H_2SO_4(0.15molL~(-1)2.5ml 作氧化体系,0.5%硫代巴比妥酸溶液3.5ml 作显色剂,于沸水浴中显色,在533nm 波长处有最大吸收,显色物在24h 内吸光度无变化在上述条件下,标准曲线线性范围为0～1.0ug/ml。γ=0.9991,=6.8×10~4dm~3mol~(-1)cm~(-1),10次平行测定 SD=0.003,RSD=0.77%;当乙醇量为山梨酸含量400倍时对测定仍无影响。     

α-生育酚、VC硬脂酸酯和槲皮素在含松籽油酸结构脂中抗氧化作用的研究

通过Schaal烘箱(60℃)氧化法,比较α-生育酚(TOH)、抗坏血酸棕榈酸酯(AP)和槲皮素(Qu)对含有松籽油酸的软质黄油基料油(SL)的抗氧化作用。结果表明:经过30d的烘箱氧化后,SL中多不饱和脂肪酸的含量减少,其中功能性松籽油酸由7.10%降低到4.60%。AP和Qu能够有效降低多不饱和脂肪酸的氧化分解,并且显著抑制结构脂的过氧化值(POV)、酸值(AV)和硫代巴比妥酸值(TBARS)。AP和Qu的抗氧化作用随着添加量增加而增强。与低添加量(100mg/kg)TOH相比,高添加量(500 mg/kg)TOH有促进氧化作用,表现为增加酸值和硫代巴比妥酸值。另外,油脂氧化不仅改变了化学性质如脂肪酸组成、酸值、过氧化值和硫代巴比妥值等,而且改变了溶解和结晶曲线,添加抗氧化剂也对油脂氧化后的溶解结晶图谱有一定影响。     

异烟酸-硫代巴比妥酸显色反应测定酒中氰化物的研究

氰化物与异烟酸-硫代巴比妥酸,在弱酸性介质和氯胺T存在的条件下可形成一种蓝色染料,该染料的最大吸收波长为642nm,且吸光度值与氰化物含量在一定的范围内呈良好的线性关系。结果表明,在pH 5.7,氯胺T用量0.4mL,氰化物转化时间4min,异烟酸-硫代巴比妥酸用量5mL的条件下,吸光度值达到最大。据此建立了酒中氰化物的异烟酸-硫代巴比妥酸分光光度法。     

亚临界丙烷、超临界CO2及正己烷对米糠油提取品质的对比研究

为探索亚临界丙烷、超临界CO_2及正己烷作为介质对米糠油提取品质的影响,对比分析了由3种介质提取所得米糠油的脂肪酸组成,γ-谷维素和α-生育酚含量,油脂氧化稳定性以及油脂颜色等。试验结果表明,3种介质提取所得米糠油的脂肪酸组成无显著差异,但γ-谷维素、α-生育酚、叶绿素和类胡萝卜素的含量有显著不同,其中亚临界对这些成分的提取量最高,分别达21.08、0.97、30.4和11.14 mg/g;米糠油的氧化稳定性试验结果显示,亚临界丙烷萃取所得的米糠油在常温下具有优越的稳定性,高于超临界CO_2和正己烷提取所得米糠油;而超临界CO_2提取所得米糠油的色泽最浅,感官品质较好。总之,亚临界丙烷对米糠油有较好的提取率和油脂的氧化稳定性,并且较充分保留了米糠油中γ-谷维素、α-生育酚、叶绿素和类胡萝卜素等生理活性成分,是一种适用于米糠油保质萃取的良好介质。     

过热蒸汽处理对米糠营养性质和储藏稳定性的影响

采用120~160℃的过热蒸汽(SS)处理米糠1~5 min,以脂肪酶活性为指标,选取钝化脂肪酶效果好的米糠样品,以原米糠为对照,考察SS处理对米糠的营养性质(总酚含量、总抗氧化性、酚酸组成变化、α-生育酚含量、γ-谷维素含量)和储藏稳定性(脂肪酸值、过氧化值、羰基值)的影响。结果表明:经120,130,140,150,160℃的SS分别处理4,4,3,3 min和2 min后米糠脂肪酶活性不再发生显著变化,此时的米糠称为最佳钝酶点米糠,其脂肪酶活性分别降至30.99%~13.41%。与原米糠相比,最佳钝酶点米糠的总酚含量、总抗氧化性、总酚酸含量显著提高,且主要贡献为阿魏酸和对羟基苯甲酸的显著增加;α-生育酚和γ-谷维素含量无显著降低。SS处理显著提高了米糠的稳定性,在第25周时,最佳钝酶点米糠的脂肪酸值、过氧化值、羰基值分别只有BR的36.0%~21.9%、50.0%~44.3%、30.3%~22.1%,有效延长了米糠储藏期。综合考虑米糠营养性质和储藏稳定性,在130℃,4 min处理条件下获得的米糠最佳。     

超声辅助提取小米谷糠油工艺优化

本研究探讨了小米谷糠前处理方式和新鲜程度对小米谷糠油提取率的影响，采用超声波辅助技术，选取最适提取溶剂，通过单因素实验和响应面分析优化小米谷糠油提取工艺，并分析了小米谷糠油脂主要理化性质及其脂肪酸组成。结果表明:选用新鲜小米谷糠，经过温度为121 ℃红外加热15 min处理；选择无水乙醇作为最佳提取溶剂，浸提时间为2 h、料液比为1:6.5 g/mL、浸提温度为56 ℃，在此条件下小米谷糠油提取率为78.57%；各因素对小米谷糠油提取率的影响程度的顺序依次为:料液比>浸提温度>浸提时间；该条件下提取的小米谷糠油酸值、过氧化值均符合《食品安全国家标准 植物油》（GB2716-2018）米糠油的指标；小米谷糠油的脂肪酸主要成分为棕榈酸、硬脂酸、油酸、亚油酸和亚麻酸，不饱和脂肪酸含量占总脂肪酸含量的90.58%，其中亚油酸含量高达72.31%。本研究提出的超声辅助无水乙醇提取小米谷糠油工艺路线是可行的，可为小米谷糠进一步开发利用提供重要的理论支撑。     

Characterization of Antioxidants Extracted from Thai Riceberry Bran Using Ultrasonic-Assisted and Conventional Solvent Extraction Methods

Riceberry bran (RBB), a waste product from rice processing, contains several antioxidants with potential health benefits. This study aims to compare the two main parameters affecting the extraction efficiency of antioxidants from RBB, namely, the extraction technique (ultrasonic-assisted extraction (UAE) and conventional solvent extraction) and solvent (ethanol and d-limonene). The highest values of total phenolic content, total flavonoid content, total anthocyanin content, and antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and ferric reducing antioxidant power (FRAP) assays were detected in ethanolic extracts obtained by UAE. High-performance liquid chromatography investigation of the chemical composition of RBB revealed five major groups of antioxidants: (1) phenolic acids, including protocatechuic acid, vanillic acid, p-coumaric acid, ferulic acid, and sinapic acid; (2) flavonoids, including rutin, myricetin, and quercetin 3-glucuronide; (3) anthocyanins, including cyanidin 3-glucoside and peonidin 3-glucoside; (4) vitamin E, including γ-tocotrienol, β-tocotrienol, δ-tocopherol, γ-tocopherol, and α-tocopherol; and (5) γ-oryzanol. Protocatechuic acid exhibited the highest DPPH radical scavenging activity and FRAP values, whereas the lowest values were observed for γ-oryzanol.     

米糠提取物超声辅助提取工艺及抗氧化活性

以乙醇为提取溶剂,采用响应面法对米糠提取物的超声辅助最佳提取工艺进行探讨。米糠提取物的总酚含量及抗氧化活性分别采用Folin-Ciocalteu 法和 Trolox 等价抗氧化能力(TEAC)方法测定。结果表明：总抗氧化活性随着总酚含量的增加而增大,但其活性高低并不完全取决于总酚物质。米糠提取物最佳提取工艺条件为乙醇体积分数90%(V/V),提取温度55℃,提取时间97min。在此条件下,米糠提取物的总酚含量为(2.76 ± 0.17)mg GAE/g米糠(n=3),总抗氧化活性为(2.99 ± 0.24)μmol TEAC/g 米糠(n=3)。     

Rice bran nutraceutics: A comprehensive review

Agro-industry yields ample quantity of several byproducts with considerable importance. These byproducts are mostly under-utilized, often used as animal feed or rejected as waste; hence their true potential is not harnessed. The use of such superfluous resources is of not only economic significance but also a form of commercial recycling. Rice bran is an important byproduct of rice milling industry with a global potential of 29.3 million tons annually. It is gaining great attention of the researchers due to its nutrient-rich composition, easy availability, low cost, high antioxidant potential, and promising effects against several metabolic ailments. Bioactive components of rice bran, mainly γ-oryzanol, have been reported to possess antioxidant, anti-inflammatory, hypocholesterolemic, anti-diabetic, and anti-cancer activities. Rice bran oil contains appreciable quantities of bioactive components and has attained the status of “Heart oil” due to its cardiac-friendly chemical profile. Nutraceutics have successfully been extracted from rice bran using several extraction techniques such as solvent extraction, supercritical fluid extraction, microwave-, and ultrasonic-assisted extraction. Current paper is an attempt to highlight bioactive moieties of rice bran along with their extraction technologies and health benefits.     

橄榄油、葵花籽油和米糠油的氧化稳定性

对橄榄油、葵花籽油和米糠油3种植物油进行氧化稳定性研究。选取在空气、光照、煎炸条件下,测定3种植物油的酸值(AV)、碘值(IV)和过氧化值(POV)。同时,在煎炸条件下,选取阿魏酸、番茄红素、β-胡萝卜素3种天然抗氧化剂对米糠油进行抗氧化性研究。结果表明：过氧化值和酸值在实验条件中上升顺序为煎炸＞光照＞空气,碘值的下降也具有此顺序。3种植物油酸值、碘值和过氧化值变化幅度的顺序为：葵花籽油＞米糠油＞橄榄油。3种天然抗氧化剂氧化速率变化顺序为：阿魏酸＞番茄红素＞β-胡萝卜素。     

Antioxidant and antimicrobial activity evaluation and essential oil analysis of Semenovia tragioides Boiss. from Iran

This study reports the essential oil composition, antioxidant and antimicrobial activity of the essential oil and methanol extract of aerial parts of Semenovia tragioides. GC and GC/MS analysis identified 17 compounds representing 99.4% of the oil. The main components comprising 61.9% of the oil were lavandulyl acetate (25.5%), geranyl acetate (12.5%), trans-β-ocimene (8.8%), p-cymene (7.7%) and γ-terpinene (7.4%). The samples were screened for their antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and β-carotene/linoleic acid assay methods. None of the plant samples showed appreciable antioxidant activity in DPPH test. However, methanol extract exhibited considerable linoleic acid oxidation inhibition (77.4%) in the β-carotene/linoleic acid test, a value near to that of butylated hydroxytoluene (BHT, 95.6%). Total phenolic content of the plant extract as gallic acid equivalents was 7.5 μg/mg. The essential oil exhibited strong antimicrobial activity against all but one of the tested microorganisms while the plant extract only inhibited two of them weakly.     

Utilization of Jujube Fruit (Ziziphus mauritiana Lam.) Extracts as Natural Antioxidants in Stability of Frying Oil

The effects of ultrasound-assisted, supercritical CO₂ and solvent extraction methods on antioxidant activity of Ziziphus mauritiana (Lam.) extracts were investigated using 2,2-diphenyl-1-picrylhydrazyl and β-carotene assays. Ethanol-water extract of the jujube that was obtained with ultrasound-assisted extraction had the highest antioxidant activity. Ultrasound-assisted extraction was the most effective method on extraction of phenolic compounds. The effect of ultrasound extract in stability of soybean oil was compared to synthetic antioxidants by measuring total polar compounds, carbonyl value, peroxide value, free fatty acids, oxidative stability index, and conjugated dienes and trienes values. Results showed that ultrasound ethanol-water extract at 600 ppm had a higher stabilization efficiency than commercial antioxidants butylated hydroxyanisole, butylated hydroxytoluene, and tertiary butylhydroquinone.     

Extraction of α-tocopherol and γ-oryzanol from rice bran

The aim of this research was to study the effect of operating mode (continuous versus batch+continuous), temperature, pressure and solvent on α-tocopherol and γ-oryzanol extraction from rice bran (Oryza sativa Linn.) and compare the efficiency of three extraction methods: SC-CO₂ extraction, solvent extraction and soxhlet extraction. Three sets of experiments were performed. First, extraction using SC-CO₂ was performed over a range of temperatures and pressures (45-65 °C and at 38 and 48 MPa), and at a CO₂ flow rate of 0.45 mL/min. The results showed that the best conditions for α-tocopherol extraction were 55 °C, 48 MPa in the batch+continuous mode. For γ-oryzanol, the best conditions were 65 °C, 48 MPa and in the continuous mode. In the second set of experiments, solvent extraction using hexane and ethanol at 32 and 55-60 °C was studied. The results showed that none of the solvents could extract α-tocopherol; however, ethanol at 55-60 °C was suitable for γ-oryzanol extraction. Finally, soxhlet extraction experiments using hexane for α-tocopherol and ethanol for γ-oryzanol were also performed. In summary, SC-CO₂ was found to be the best solvent for extracting both α-tocopherol and γ-oryzanol from rice bran, because of its higher yields and extraction rate.     

米糠蜡添加量对亚麻籽油基油凝胶结构及性质的影响

为探究亚麻籽油基油凝胶作为替代传统塑性脂肪的潜力,以米糠蜡为凝胶剂,探究不同米糠蜡添加量对亚麻籽油基油凝胶外观形态、微观结构、持油率、理化性质及热力学性质的影响。结果表明：在室温条件下,米糠蜡添加量不小于6%时才会使亚麻籽油凝胶化;随着米糠蜡添加量的增加,油凝胶的结晶网络结构由簇状逐渐转变为针状,结晶密度增大;油凝胶的持油率、酸值以及熔融峰/结晶峰峰值温度均随着米糠蜡添加量的增加而增大;油凝胶的过氧化值随着米糠蜡添加量的增加呈现先增后减的趋势。综上,在亚麻籽油中添加适量的米糠蜡可形成热塑性好、结构稳定、理化性质良好、持油率高的油凝胶。