油茶籽油不同形态酚类化合物的抗氧化互作关系

本研究首先对油茶籽油中游离酚（free phenolics，FP）、酯化酚（esterified phenolics，EP）及不溶性结合酚（insoluble-bound phenolics，ISP）含量及主要物质组成进行分析，并通过测定铁离子还原能力、2,2’-联氮双(3-乙基苯并噻唑啉-6-磺酸)阳离子自由基清除能力、1,1-二苯基-2-三硝基苯肼自由基清除能力及β-胡萝卜素漂白能力对其中FP、EP及ISP的抗氧化活性及互作关系进行研究。结果表明，油茶籽油总酚含量为（137.97±5.14）mg/kg，其中ISP含量显著高于FP及EP（P＜0.05），占油茶籽油总酚的47.74%。另外，FP中以苯甲酸衍生物含量较高（主要为异香兰素及甲基香兰素），EP中主要为水杨酸，ISP中主要为3,4-二羟基扁桃酸。3 种形态酚类化合物在不同机制下的抗氧化能力不同，且呈现质量浓度依赖效应。FP＋ISP组合及EP＋ISP组合在抗氧化互作方面表现出一定的协同或相加作用，且后者复配组合的抗氧化活性更强；而FP＋EP组合和FP＋EP＋ISP组合则表现出拮抗或相加作用。     

茶叶籽油中酚类化合物的提取工艺优化及其抗氧化相互作用动力学研究北大核心CSCD

为揭示二元酚类复合物的抗氧化相互作用机制,采用碱解法结合有机溶剂对茶叶籽油中酚类化合物进行提取。通过单因素实验及正交实验优化酚类化合物提取工艺条件,采用超高效液相色谱-串联质谱(UPLC-MS/MS)分析酚类化合物组成,并对7种酚类化合物及其21组二元复合物的DPPH·清除动力学进行研究。结果表明:茶叶籽油中酚类化合物最佳提取工艺条件为乙酸乙酯为萃取剂、NaOH浓度2.0 mol/L、碱解温度45℃、碱解时间5 h、料液比1∶15,在最佳条件下总酚含量可达(91.37±1.83)μg/g;共鉴定出22种酚类化合物,总含量达152.181μg/g,以酚酸类化合物(82.021μg/g)为主;6,7-二羟基香豆素与龙胆酸的复合物具有强协同作用,二元酚类复合物对DPPH·的清除速率受单体相互作用及起主要抗氧化作用酚类化合物的清除速率的影响,同时酚类化合物的相互作用在抗氧化过程中会发生改变。因此,茶叶籽油的耐储藏性与酚类化合物间的抗氧化协同作用密切相关。     

硬毛地笋酚类化合物对DNA损伤的保护作用

采用超声波辅助提取技术从硬毛地笋中提取游离酚（free phenolics,FP）和不溶性细胞壁结合酚（insoluble cell wall bound phenolics,ICP）,采用福林-酚法测定酚含量。同时采用高效液相色谱法对硬毛地笋酚类化合物的组成进行分析。通过体外DNA损伤模型考察硬毛地笋酚类化合物提取物对过氧自由基（ROO·）介导的DNA氧化损伤的保护作用。同时,对提取物酚含量与其保护DNA损伤作用之间的相关性进行了分析。结果表明：硬毛地笋酚类化合物对ROO·介导的DNA损伤均具有不同程度的保护作用。其中FP对DNA损伤的保护作用强于ICP;2016年12月15日和2017年1月14日采收的硬毛地笋ICP含量与其保护DNA损伤的作用具有显著正相关性（P＜0.05）。     

响应面优化超声波辅助提取油茶花中总酚工艺研究

本研究以海南油茶花为原料,运用超声波辅助,响应面法优化提取海南油茶花中总酚,从而获得海南油茶花总酚提取的最佳条件。通过选取以料液比、提取剂乙醇体积分数、超声温度、超声时间为参数自变量,采用Box-Behnken中心组合法,以海南油茶花总酚为响应值,探究4种参数自变量对海南油茶花中总酚提取得率的影响。结果表明,超声波辅助获取油茶花总酚的最佳工艺条件为:料液比1∶600(g/mL),乙醇溶剂体积分数30%,超声温度60℃,超声时间20min,在此最优条件下验证试验油茶花的总酚平均提取得率为(13.03±1.34)%。优化海南油茶花总酚超声波辅助提取的工艺条件,对应用于工业生产及油茶花的综合开发利用具有重要意义。     

响应面优化超声波辅助提取油茶花中总酚工艺研究

本研究以海南油茶花为原料,运用超声波辅助,响应面法优化提取海南油茶花中总酚,从而获得海南油茶花总酚提取的最佳条件。通过选取以料液比、提取剂乙醇体积分数、超声温度、超声时间为参数自变量,采用Box-Behnken中心组合法,以海南油茶花总酚为响应值,探究4种参数自变量对海南油茶花中总酚提取得率的影响。结果表明,超声波辅助获取油茶花总酚的最佳工艺条件为:料液比1∶600(g/mL),乙醇溶剂体积分数30%,超声温度60℃,超声时间20min,在此最优条件下验证试验油茶花的总酚平均提取得率为(13.03±1.34)%。优化海南油茶花总酚超声波辅助提取的工艺条件,对应用于工业生产及油茶花的综合开发利用具有重要意义。     

响应面优化油茶籽油游离型特征酚和总酚工艺

使用甲醇提取溶剂,采用超声波辅助提取冷榨油茶籽油中以反-肉桂酸和4-羟基苯乙酸为主的游离型多酚化合物。基于单因素试验和响应面分析,优化了游离型特征酚和总酚提取工艺,建立了数学回归模型,分析了各因素间的交互作用。结果表明,影响油茶籽油游离型多酚含量的显著因素为料液比、超声功率和提取时间,最佳工艺为料液比1:19.73(g/mL)、超声功率265.77 W、提取时间31.86 min,此时总酚、反-肉桂酸和4-羟基苯乙酸含量分别为99.10 mg/kg、520.70 μg/kg和348.14 μg/kg。验证结果与理论预测拟合度高,可为后期油茶籽油不同形态多酚提取与鉴定,油茶籽油适度加工过程多酚保留与调控提供理论依据。     

响应面优化单溶剂体系棉酚提取工艺研究

为了降低棉粕的毒性及最大限度地提取棉酚,以棉仁为原料,以甲醇为溶剂,采用溶剂浸出法对棉仁中游离棉酚的提取工艺进行研究。在单因素试验的基础上,通过响应面法对工艺条件进行优化。结果显示各因素影响游离棉酚提取率的主次顺序为:提取时间料液比提取温度搅拌速率;得到的最佳工艺条件为:料液比1∶24,提取温度35℃,提取时间42 min,搅拌速率2 600 r/min,提取次数2次(即先以料液比1∶12提取,提取21 min,再以料液比1∶12提取,提取21min);在最佳工艺条件下,游离棉酚的提取率为68.9%±0.81%,其纯度为81.9%±0.85%。此时,棉粕中游离棉酚残留量为839.7 mg/kg,小于饲料卫生标准(GB 13078—2001)中所规定的棉籽饼、粕中允许的游离棉酚最大残留量1 200 mg/kg。     

油茶籽油中苯并(a)芘的形成与控制

通过研究热榨、冷榨、浸出和不同精炼工序对油茶籽油中苯并(a)芘(BaP)含量的影响,探索了茶籽油中BaP的形成原因。结果表明,冷榨毛油中BaP含量为(2.56±0.0804)μg/kg,其无需精炼即可达到食用安全要求(≤10μg/kg);导致传统热榨-浸出制油工艺中油脂的BaP超标的主要原因是高温而不是浸出溶剂;碱炼工序会促进BaP含量大量增加,高温脱臭工序也会提高BaP含量(增幅约84%～247%);而脱色、冬化工序可以降低油脂中的BaP(降幅约71.5%～85.9%)。因此,在油茶籽油生产与加工过程中,应尽量避免使用高温条件;毛油精炼工艺应包含脱色和冬化工序,同时应控制碱炼与脱臭工艺条件,使茶籽油得到适度精炼,以确保其食品质量安全。     

基于Box-Behnken-Matlab分析法优化高亚油酸含量南瓜籽油提取工艺研究

本研究以低温锡箔烘焙裸仁南瓜籽为对象,采用超声辅助溶剂法提取南瓜籽油,运用Box-Be-hnken-Matlab分析法对南瓜籽油进行基于亚油酸(LA)相对含量(Y₁)和粗油得率(Y₂)的提取工艺优化。结果表明：采用Box-Behnken-Matlab分析法得到南瓜籽粗油最优提取工艺参数为：超声时间15 min,料液比1∶38.65,提取温度25.75℃,提取时间2.7 h,此时,Y₁可达(48.23±0.11)%,Y₂为(24.83±0.12)%;当超声时间15 min,提取时间的范围为2.5～3 h,料液比1∶34～1∶39,提取温度22～27℃时,在此工艺参数区间Y₁和Y₂可同时取得较大理论值,此时,粗油中总酚含量为(968.71±13.96)mgGAE/kg。研究表明,Box-Behnken-Matlab分析法不仅可以得到高LA相对含量的南瓜籽油最优工艺参数,也可以在兼顾LA相对含量和粗油得率的情况得到较优工艺参数范围,为高活性南瓜籽油工业化提取提供...     

水酶法同时提取油茶籽油及蛋白研究

采用水酶法从油茶籽仁中同时提取油与蛋白。经筛选,使用碱性蛋白酶水解油茶籽仁水液,并对酶解工艺条件进行优化。通过单因素实验及正交试验,确定水酶法提取油茶籽油和蛋白的最佳工艺参数为料液比1∶5、蛋白酶用量1.5%、酶解p H 8,酶解温度60℃、酶解时间4 h。在此最佳条件下进行实验验证,油茶籽油得率为74.61%,油茶籽蛋白得率为82.28%。     

Biological properties of olive oil phytochemicals

Olive oil is the principal source of fat in the Mediterranean diet, which has been associated with a lower incidence of coronary heart disease and certain cancers. Extra-virgin olive oil contains a considerable amount of phenolic compounds, for example, hydroxytyrosol and oleuropein, that are responsible for its peculiar taste and for its high stability. Evidence is accumulating to demonstrate that olive oil phenolics are powerful antioxidants, both in vitro and in vivo; also, they exert other potent biological activities that could partially account for the observed healthful effects of the Mediterranean diet.     

Binding of olive oil phenolics to food proteins

In this paper we investigate the interaction of phenolics extracted from olive oil with different food proteins (sodium caseinate, bovine serum albumin, β‐lactoglobulin and gelatin). Binding parameters are estimated using different experimental techniques: gel filtration, HPLC, isothermal titration calorimetry and NMR diffusion measurements. For comparison, the binding properties of gallic acid and tannic acid are also studied. The affinity of olive oil phenolics for the different food proteins is found to be relatively weak (compared with tannic acid). Binding constants are measured for the different phenolics in the extract: tyrosol and hydroxytyrosol do not (or very weakly) bind to the proteins, whereas other phenolics in the extract had binding constants of the order 10²–10⁴ M ^?1. The binding parameters determined have been discussed in relation to the possible effect of proteins on sensory properties (bitterness) of food emulsions containing olive oil. Copyright © 2004 Society of Chemical Industry     

橄榄油质量鉴别若干内源性标记物

橄榄油真实性最突出的问题是特级初榨橄榄油掺精炼橄榄油。脂肪酸组成分析的传统鉴别方法日益受到挑战,对基于橄榄油中的甘油二酯异构体、蜡质植物甾醇、反式脂肪酸、甘油三酯聚合物等若干重要的内源性鉴别标记物作了评介。特异性、灵敏度和准确性更加完善的方法尚待研究。     

Contribution of olive seed to the phenolic profile and related quality parameters of virgin olive oil

BACKGROUND: Conflicting results have been reported about the effect of fruit de‐stoning on the virgin olive oil (VOO) phenolic profile. The aim of the present study was to determine whether olive seed plays any role in the synthesis of this oil phenolic fraction. RESULTS: Increases of around 25% of total phenolic compounds were observed in oils obtained from de‐stoned olive fruits in three main Spanish cultivars. To investigate the involvement of olive seed in determining the phenolic profile of VOO, whole intact olive fruits were added with up to 400% olive stones. Excellent regression coefficients were found in general for the decrease of total phenolic compounds and, particularly, of o‐diphenolics in the resulting oils. On the other hand, it was found that olive seed contains a high level of peroxidase (POX) activity (72.4 U g^?1 FW), accounting for more than 98% of total POX activity in the whole fruit. This activity is able to modify VOO phenolics in vitro, similar to the effect of adding stones during VOO extraction. CONCLUSION: Olive seed plays an important role in determining VOO phenolic profile during the process to obtain an oil that seems to be associated with a high level of POX activity. Copyright © 2007 Society of Chemical Industry     

Phenylalanine ammonia lyase (PAL) enzyme activity and antioxidant properties of some cyanobacteria isolates

In the present study, six cyanobacteria isolates were evaluated for the PAL enzyme activity, and their methanol extracts were assessed for the total phenolic amount and other antioxidant parameters. Synechocystis sp. BASO444 and Synechocystis sp. BASO673 isolates with high levels of total phenols (66.0 ± 1.2 μg/mg, 78.1 ± 1.8 μg/mg, respectively) also showed high levels of PAL activities (20.5 ± 3.1 U/mg protein, 17.2 ± 2.3 U/mg protein, respectively) and strong antioxidant activities. To understand the effect of l-phenylalanine (l-phe) on the PAL activity, total phenolic amount, and phenolic constituents, isolates were evaluated with 100 mg/l l-phe. While PAL activities exhibited no significant change with l-phe addition, total phenolic amount of the isolates significantly increased. HPLC analysis revealed gallic acid, trans-cinnamic acid, p-coumaric acid, and ferulic acid as the main compounds. Results suggested that the two isolate mights be an important source for the l-phe inducible phenolic compounds.     

Antioxidant activities of Thai pigmented rice cultivars and application in sunflower oil

An analytical comparison for active chemical compounds and their antioxidant activities between three representative pigmented Thai rice cultivars was performed. It was revealed that the darkest purple‐red cultivar (Kum Doi Musur, KDM) contained the highest total phenolic content of 1164.6 mg gallic acid equivalent per100 g (dry basis, db) and the highest total monomeric anthocyanin content of 381.7 mg per100 g (db), when compared with the purple cultivar (Riceberry) and the red cultivar (Sungyod). Its 2,2‐diphenyl‐1‐picrylhydrazyl radical scavenging activity and ferric reducing antioxidant power were also the highest. When applied in sunflower oil, the KDM crude extract was efficiently capable of retarding lipid peroxidation as assessed by peroxide value, p‐anisidine value, totox value and the Rancimat method. Results show this specific pigmented rice to be a potent antioxidant for stabilisation of sunflower oil.     

Impact of oil used by the frying industry on population fat intake

Chronic multifactorial diet related diseases are the major causes of death and illness worldwide. The amount and composition of fat in the diet is an important determinant of the pathobiology of many of these conditions. In the current review the associations between dietary fat and disease risk will be considered. Mean population fat intakes will be compared with dietary recommendations aimed at reducing the population burden of disease and the main sources of fat in the adult and childhood diet will be given. An assessment will be made of the principal vegetable oil sources used in the manufacture of processed foods, in particular fried foods, with particular reference to the rheological and nutritional justification for their use. The impact of the more widespread use of alternative oil sources with improved fatty acid profiles, on the fat composition of fried foods and the overall diet will be presented, demonstrating that such apparently focussed approaches could potentially result in a significant impact on population fat intake and potentially overall chronic disease burden.     

鱼油纳米脂质体的制备及其性质测定

采用响应面法优化乙醇注入-动态高压微射流法制备鱼油纳米脂质体的工艺,并对其理化性质进行了初步测定。结果表明:制备鱼油纳米脂质体的最佳工艺为:磷脂浓度29 mg/mL,m(磷脂)∶m(鱼油)∶m(胆固醇)∶m(吐温-80)=10∶2∶2.5∶1,微射流压力150 MPa,微射流处理次数2次。在此条件下脂质体的包封率为76.9%,平均粒径128.1 nm,Zeta电位-20.11 mV。乙醇注入-动态高压微射流法制备的鱼油纳米脂质体粒径小且分布均匀(多分散指数0.258),具有较高的包封率和稳定性。     

牛至精油活性膜对黑鱼片的保鲜效果

以牛至精油作为抗菌剂,分别加入到乙烯—乙烯醇共聚物(EVOH)和聚乙烯(PE),通过挤出流延制备成2种食品保鲜膜。对保鲜膜的机械性能、透光率和雾度进行表征。用2种保鲜膜包装黑鱼,测定其汁液流失率、pH值、硫代巴比妥酸(TBA)和菌落总数随贮藏时间的变化。结果显示,牛至精油的加入对薄膜的基本性能影响不大;保鲜膜能够减缓所包装黑鱼片的汁液流失率、pH值的增长速度,抑制鱼肉脂质氧化。空白组鱼肉样品的菌落总数在第4天就几乎到达了6lg CFU/g,而含精油的样品组的菌落总数在第8天才接近6lg CFU/g。从菌落总数的变化来看,相对于空白组,含精油的保鲜膜能够减缓包装鱼肉中微生物的生长速度。     

深海粗鱼油的精炼工艺研究

对深海杂鱼粗鱼油精炼工艺进行优化,考察了磷酸体积分数、超量碱和活性白土添加量对鱼油酸值、回收率和感官品质的影响,并对精炼鱼油的理化指标及脂肪酸组成进行分析。结果表明:适宜的精炼条件为采用占鱼油质量1%、体积分数80%的磷酸脱胶,脱胶油中加入占鱼油质量1.5%的超量碱和理论碱量的Na OH(4 mol/L)脱酸,脱色选用添加占鱼油质量20%的活性白土;精炼鱼油的理化指标均达到我国水产行业精制鱼油的一级标准(SC/T 3502—2000),酸值(KOH)由(5.52±0.12)mg/g下降到(0.29±0.11)mg/g;精炼工艺对鱼油脂肪酸组成的影响较小,其中二十碳五烯酸和二十二碳六烯酸的总量约占总脂肪酸含量的38%,且分别占多不饱和脂肪酸含量的35.99%和51.59%,品质较优。