基于响应面法构建虾青素纳米乳液

为提高虾青素的稳定性,以生物大分子卵磷脂为乳化剂,采用高压均质法制备负载虾青素的纳米乳液,在单因素实验的基础上,以纳米乳液粒径和虾青素负载率为响应值,以乳化剂浓度、油水比、虾青素添加量3个因素为响应因子,利用响应面法建立二次回归方程模型,获得制备虾青素纳米乳液的最佳工艺条件为:乳化剂浓度1%(w/w),乳化温度55 ℃,乳化时间45 min,油水比1:8.5,虾青素添加质量分数为0.5%(w/w),按此工艺条件制备得到虾青素纳米乳液的粒径为238.84 nm,虾青素负载率可达到90.41%。     

不同处理方式对柑橘纤维形态结构的影响研究

本研究探讨了三种柑橘纤维[AQ-Plus (1号),Fiber-Star (2号)和在我们的实验室中提取的纤维(3号)]之间基本成分、物理性质(持水性、持油性以及膨胀性)的差异;通过测定柑橘纤维悬浮液的粒径、Zeta电位、表观黏度以及微观结构来探讨高压均质、超声波处理对三种柑橘纤维悬浮液的形态表征的影响。实验结果表明:1号纤维素(38.02±1.61 g/100 g)、半纤维(29.56±0.63 g/100 g)含量较高,持水性(21.58 g/g)、持油性(14.29 g/g)以及膨胀性(27.46 mL/g)较好,2号次之,3号最差;经过30 MPa,60℃高压均质处理,三种柑橘纤维粒径降低,Zeta电位、表观黏度较未处理前显著提升;随着超声波处理时间的增加,三种柑橘纤维的粒径逐渐下降,表观黏度呈现递增的趋势;在0～5min处理过程中,三种柑橘纤维悬浮液Zeta电位绝对值随着超声波处理时间的增加而显著提高,随着超声时间的进一步延长,三种柑橘纤维Zeta电位无显著变化。     

Stabilization of astaxanthin in edible oils and its use as an antioxidant

Astaxanthin, a ketocarotenoid (3,3′‐dihydroxy‐β,β‐carotene‐4,4′‐dione), is produced in high concentration in the green alga Haematococcus pluvialis. It constitutes 85–88% of total carotenoid and exists in the monoester, diester and free form. Astaxanthin in its ester form is fairly stable in all edible oils such as rice bran, mustard, groundnut, gingelly, coconut and palm oil at room temperature with variation in terms of its loss in content and colour during a 4 month period. Rice bran, gingelly and palm oil retained 84–90% of astaxanthin when heated at 70 °C for 8 h while palm oil was effective in retaining 90% of astaxanthin at 90 °C for 8 h without any change in its ester form in comparison to 90% carotenoid loss in aqueous form. At 120 and 150 °C, carotenoid loss was significant (60–90%) without change in the fatty acid profile of the edible oils. The antioxidant activity of carotenoids stored in oils was comparable to standard butylated hydroxy anisole (BHA). Copyright © 2007 Society of Chemical Industry     

壳聚糖纳米粒子的制备方法及其作为药物递送载体的应用

虾青素（Astaxanthin,AST）是一种脂溶性叶黄素类胡萝卜素,具有良好的抗氧化、抗炎和免疫调节活性。然而,因其口服生物利用度较差,临床应用有限。近年来,为了提高虾青素的生物利用度,各种类型的纳米制剂被广泛研究。其中纳米乳液、脂质体、固体脂质纳米颗粒、壳聚糖纳米颗粒和聚乳酸-羟基乙酸聚合物（poly（lactic-co-glycolic acid）,PLGA）纳米颗粒已被证明可有效提高虾青素的口服生物利用度。本综述中,基于体外和体内研究数据和结果,总结了不同类型的纳米制剂对于提高虾青素口服生物利用度的研究进展,为今后虾青素口服剂型的开发提供参考,实现其在临床中的应用价值。

     

Rheology and microstructure of carrot and tomato emulsions as a result of high-pressure homogenization conditions

High-pressure homogenization, as a way to further mechanically disrupt plant cells and cell walls compared to conventional blending, has been applied to thermally treated and comminuted carrot and tomato material in the presence of 5% olive oil. Mixes of both vegetables in a 1:1 ratio were also included. Both the effect of homogenization pressure and the effect of multiple process cycles were studied. The different microstructures generated were linked to different rheological properties analyzed by oscillatory and steady state measurements. The results showed that while carrot tissue requires a high shear input to be disrupted into cells and cell fragments, tomato cells were broken across the cell walls already at moderate shear input, and the nature of the tomato particles changed to amorphous aggregates, probably composed of cell contents and cell wall polymers. All the plant stabilized emulsions generated were stable against creaming under centrifugation. While for tomato a low-pressure multiple cycle and a high-pressure single-cycle process led to comparable microstructures and rheological properties, carrot showed different rheological properties after these treatments linked to differences in particle morphology. Mixes of carrot and tomato showed similar rheological properties after homogenizing in a single or in a split-stream process. Practical Application: Following consumers' demand, the food industry has shown a growing interest in manufacturing products free of gums and stabilizers, which are often perceived as artificial. By tailored processing, fresh plant material could be used to structure food products in a more natural way while increasing their nutritional quality.     

菠萝皮渣生产虾青素的发酵条件研究

以菠萝皮渣为培养基的主要原料,采用法夫酵母（Phaffia rhodozyma）对其进行发酵生产虾青素,采用响应面分析法对法夫酵母的发酵条件进行优化研究。先用Plackett-Burman设计法实验确定重要因素,再用最陡爬坡实验法确定因素水平,最后用响应面分析方法求得的最佳发酵条件为：发酵温度为20.0℃,初始pH为5.29,糖度为6.1%,酵母膏2g/L,MgSO42g/L,（NH4）2SO44g/L,KH2PO41.5g/L,种龄36h。用此优化的发酵培养基培养法夫酵母,虾青素产量可达6.5751mg/L。     

薄荷油纳米乳液的制备及其性质分析

为克服薄荷油易挥发、不易溶于水的缺点,以大豆分离蛋白-磷脂酰胆碱复合物作为乳化剂,采用高压均质法制备薄荷油纳米乳液,研究大豆分离蛋白质量分数、薄荷油质量分数及均质压力对薄荷油纳米乳液的平均粒径、多分散性指数、Zeta电位、浊度、乳化产率、乳液稳定性指数的影响,并确定制备薄荷油纳米乳液的最佳工艺参数为：大豆分离蛋白质量分数2.5%、薄荷油质量分数5%、均质压力80 MPa。通过动态光散射和透射电镜验证最佳条件制备的薄荷油纳米乳液平均粒径小且分布均匀;通过气相色谱-质谱检测发现大豆蛋白-磷脂酰胆碱为乳化剂制备的纳米乳液可有效保护薄荷油功能成分;流变学特性结果表明薄荷油纳米乳液具有良好的动力学稳定性。     

Inactivation of vegetative cells by continuous high-pressure processing: new insights on the contribution of thermal effects and release device

Dynamic or continuous high-pressure processing of fluid foods has drawn significant interest as a microbial reduction process in the past decade, and many attempts have been made to better understand the mechanisms involved in that reduction. This study was intended to provide insight into the contributions of thermal effects and differences in pressure release components in the inactivation of 2 vegetative pathogen analogs--the Gram-positive Listeria innocua and the Gram-negative Escherichia coli. Fluids containing microbial loads of 10(8) or greater were subjected to continuous high-pressure processing at 200 to 210 MPa. Without active cooling of the release components, all fluids experienced a temperature rise in excess of 70 °C, thus occluding any pressure-related effects for all release components. Active cooling of the valve bodies of the 2 valve-style release components (a conical disruption valve and a micrometering valve) allowed the temperature rise to be abated enough to isolate the effects unique to a given valve. In Tryptic soy broth trials, the mean inactivation levels of E. coli between valves were similar--5.16 log and 5.33 log for the micrometering and conical disruption valves, respectively. When repeated with L. innocua, a similar inactivation level was observed in the conical disruption valve (5.1 log) but not the micrometering valve (3.02). Listeria innocua trials were also repeated using fluid whole milk, which showed a lower levels of inactivation--2.04 log for the micrometering valve and 2.51 log for the conical valve. PRACTICAL APPLICATIONS: This paper compares some of the most common pressure release components used in continuous high-pressure processing and attempts to isolate the contributions of thermal effects from those of pressure and shear. This information is important to those seeking to compare and evaluate the effectiveness of a proposed set of process parameters for microbial inactivation. Further, the ability to reduce the extreme nature of the temperature rise has the potential to expand the use of process into more temperature sensitive products.     

Effects of High Pressure Homogenization on Beer Quality Attributes

The aim of the present study was to evaluate the use of high pressure homogenization (HPH) as an alternative to thermal pasteurization for beer stabilization and to evaluate the effect of processing on colour, haze and redox potential immediately after the process and during the product shelf‐life (100 days). The results obtained showed good colour retention, changes in the redox potential and greater values for turbidity, presenting a higher value for the product treated by HPH than for the thermally treated samples reported in literature. The evaluation of the results indicated that the HPH process is a promising process for beer treatment in terms of guaranteeing better colour retention. However to make this product stable, it would be necessary to perform stabilization treatments to minimize the negative effects of processing on the haze of the final product.     

不同品种大豆分离蛋白Zeta电位和粒径分布与表面疏水性的关系

对不同品种大豆分离蛋白(soybean protein isolate,SPI)的表面疏水性、氨基酸组成及溶液的Zeta电位和粒径分布进行分析,探讨蛋白质溶液Zeta电位和粒径分布与表面疏水性的关系。不同品种SPI的表面疏水性由大到小的变化趋势为:东农46皖豆24黑农46五星4中黄13冀NF58,品种差异对SPI的Zeta电位及粒径分布具有显著影响。相关性分析表明,SPI表面疏水性与氨基酸组成无显著相关性,表面疏水性与Zeta电位绝对值呈显著的正相关,与粒径大小呈显著的负相关。当蛋白溶液Zeta电位绝对值较大时,蛋白表面更多同性电荷间的排斥作用会减少蛋白分子的相互聚集,使蛋白溶液趋于稳定,同时降低蛋白质粒径大小。此时,蛋白质疏水基团的内卷程度降低,并更多暴露在分子表面,导致蛋白质表面疏水性增加。     

蛇油纳米乳的制备及稳定性评价

通过水相滴定法制备蛇油纳米乳,研究了混合油相、表面活性剂、助表面活性剂对蛇油纳米乳制备的影响,并利用伪三元相图法确定最佳蛇油纳米乳配方。结果表明：混合油相选择蛇油和肉豆蔻酸异丙酯（IPM）,表面活性剂选择Span80和Tween80二者质量比27∶ 73,助表面活性剂选择PEG400;最佳蛇油纳米乳配方为蛇油1.6 g、IPM 2.4 g、Span80 1.08 g、Tween80 2.92 g、PEG400 4.0 g、水8.0 g。所制得的蛇油纳米乳为O/W型,平均粒径为63.01 nm,PDI为0.226,Zeta电位为-19 mV,液滴外观为圆形,粒径均匀且状态良好;离心后清澈透明,不分层;不耐高温,需要在25 ℃以下贮存;冷冻后,可以在室温下恢复到初始状态;氧化稳定性较蛇油提高     

美拉德反应制备等电点澄清透明的乳清分离蛋白研究

本文旨在以乳清分离蛋白(WPI)为原料,研究其与糖类物质的美拉德反应制备得到产物在等电点附近的溶解性、乳化性(EAI)、乳化稳定性(ESI)和热稳定性等功能特性,为其在透明饮料中的应用奠定基础。在相对湿度79%,温度70℃的反应条件下制备得到乳清分离蛋白与L-乳糖的美拉德反应产物,聚丙烯酰胺凝胶电泳(SDS-PAGE)实验结果证实了美拉德反应使WPI中α-乳清蛋白和β-乳球蛋白分子量分别增加2~3 ku左右;邻苯二甲醛(OPA)结果表明在美拉德反应时间为12 h时,WPI中游离氨基酸含量减少35%左右;美拉德反应改性使其溶解性、乳化性(EAI)、乳化稳定性(ESI)和热稳定性都有显著提高(在10 min时EAI和ESI分别为0.35 m~2/g和20 min,为WPI的1.5倍和1.7倍);电位和粒径结果显示,乳清分离蛋白糖基化产物的溶解性和热稳定性增强是因为蛋白质表面引入糖分子的位阻效应所致,而非静电作用。     

pH值和金属阳离子对水性油墨胶体稳定性的影响

研究了pH值和Na 、Ca2 、Al3 对水性油墨胶体体系稳定性的影响。研究结果表明,当pH值<4.0时,水性油墨胶体体系发生失稳现象。pH值为3.1时,水性油墨粒子Zeta电位达到等电点,pH值<3.1时油墨粒子表面带正电荷。加入Na 、Ca2 和Al3 均可增加水性油墨粒子的平均粒径,而Al3 的效果最为显著,当Al3 浓度为0.005mol/L时,炭黑聚集体的粒径可达到5210nm,体系的Zeta电位为5.2mV。降低pH值及添加Al3 均能明显降低水性油墨的浊度值并使油墨粒子发生明显的聚沉作用。     

低毒高效提取雨生红球藻中虾青素的工艺优化

随着虾青素的应用范围不断扩大,提取剂的安全性问题也日益突出。以雨生红球藻为原料,研究了多种提取剂的得率,以选出低毒高效的提取溶剂。同时,还研究了料液比、温度及提取时间对雨生红球藻中活性成分虾青素得率的影响,并通过正交实验优化提取参数,获得最佳提取工艺。结果显示,各因素对得率的影响大小依次为:料液比>提取时间>温度>提取溶剂。提取溶剂、料液比、温度和提取时间的最佳条件分别是:乙酸乙酯∶乙醇(1∶1)、1∶100、40℃、20 min,最佳得率为49.96%。      

Improvement of the ACE‐inhibitory and DPPH radical scavenging activities of soya protein hydrolysates through pepsin pretreatment

This study aimed to investigate the effect of pepsin pretreatment on the ACE‐inhibitory and DPPH radical scavenging activities of soya protein hydrolysates prepared with alcalase and protamex. The protein recovery, TCA‐soluble peptide content, surface hydrophobicity, particle size and zeta potential were evaluated. Results showed that the hydrolysates exhibited varying ACE‐inhibitory (i.e. the highest value 72.6% by alcalase and 84.3% by protamex) and DPPH radical scavenging activities (i.e. the highest value 51.9% by alcalase and 51.7% by protamex). Pepsin pretreatment could make soya proteins more susceptible for hydrolysis, and the results showed that the ACE‐inhibitory and DPPH radical scavenging activities of the resultant hydrolysates were improved. A highly significant positive correlation between ACE‐inhibitory and DPPH radical scavenging activities was observed in the alcalase hydrolysates, while no significant correlation among other treatments. The physical properties of hydrolysates, that is surface hydrophobicity, particle size and zeta potential, could influence their ACE‐inhibitory and DPPH radical scavenging activities.     

喷雾干燥工艺对胶束态酪蛋白结构及抗氧化性的影响

以脱脂牛乳为原料,采用超滤技术获得胶束态酪蛋白,研究进口温度130℃和150℃、雾化压力0. 05 MPa和0. 1 MPa喷雾干燥工艺下胶束态酪蛋白粉末的水分含量、粒径、堆积密度、表面形貌、溶解性、内源荧光特性以及抗氧化活性(还原力、Fe²⁺螯合力、DPPH和ABTS自由基清除活力),并以冷冻干燥样品为对照。结果显示,随着喷雾干燥温度和雾化压力的升高,胶束态酪蛋白粉末的水分含量显著降低(P <0. 05),堆积密度显著增大(P <0. 05),粒径在150℃-0. 1 MPa条件下最大,为(2. 16±0. 29)μm;冻干胶束酪蛋白的粒径最小,为(1. 31±0. 02)μm,堆积密度最大,为(416. 47±3. 94) mg/m L,水分含量与130℃-0. 1 MPa和150℃-0. 05 MPa下喷干样品差异不显著(P>0. 05)。随着喷干温度和压力的升高,胶束态酪蛋白的溶解性和内源荧光强度呈现下降趋势,但最大发射波长和表面形貌不变。冻干样品的溶解性在p H 7时为(87. 63±0. 35)%,与130℃-0. 05 MPa下的喷...     

New association of surfactants for the production of food and cosmetic nanoemulsions: preliminary development and characterization

A new nanoemulsifing system has been developed. This study refers to an innovative association of polysorbate 80 and palmitic ester of l-ascorbic acid for the production of good stability and very thin nanostructured emulsions with average micellar diameter size ranging from 100 to 300 nm. This system has showed to be very performing to create nanoemulsions with moderate stirring rate and warming regimen thanks to the high efficiency of the association between ascorbyl palmitate and polysorbate-80 (PS-80). This nanoemulsified system is very easy to achieve and shows a very good capability to encapsulate several substrates of both nutritional and cosmetic usage such as melatonin, resveratrol, essential oils and steroidic terpenes such as boswellic acids and others. This system has been optimally applied to nutraceutical and cosmetic formulations and particularly to develop sprayable sublingual delivery systems for melatonin and the aforesaid molecules. This study describes developing and analytical characterization of this system containing melatonin.     

不同热处理温度下大豆11S球蛋白Zeta电位、粒径和红外光谱分析

对不同热处理条件下大豆11S球蛋白的Zeta电位、粒径和红外光谱进行研究。随着热处理时间的延长,80?℃和90?℃条件下大豆11S球蛋白的Zeta电位绝对值逐渐减小,而100?℃条件下Zeta电位绝对值呈先减小后增大的趋势,3?个温度条件下11S球蛋白的平均粒径逐渐增加。100?℃热处理的Zeta电位绝对值变化更显著,平均粒径更大。Zeta电位和平均粒径的变化与热处理改变了蛋白质的分子结构有关。对于2%的大豆11S球蛋白溶液,80?℃热处理过程中β-转角和无规卷曲结构的转化可能相互抵消,而最终表现为α-螺旋结构转变为β-折叠结构;90?℃热处理前30?min发生α-螺旋和β-折叠结构向β-转角结构转变,超过30?min各二级结构不再相互转化;100?℃热处理前20?min会使α-螺旋和β-折叠结构迅速转变为β-转角和无规卷曲结构,20～45?min各二级结构没有相互转化,而超过45?min后这种转变进一步加强。