糖玻璃化抗坏血酸胶囊制备的挤压工艺研究

采用挤压法制备糖玻璃化抗坏血酸胶囊,考察了挤压腔温度、螺杆转速和喂料速度对挤压过程中电机扭矩（扭矩百分比）、模头压力的影响。分析了挤压产品的还原性抗坏血酸含量、产率和挤压产品玻璃化转变温度等理化指标。结果表明:提高挤压腔温度、增加螺杆转速和降低喂料速度可以减小电机扭矩及模头压力。确定的挤压腔温度、螺杆转速和进料速度分别为中温（85℃-105℃-120℃-105℃）、60r/min和1.1kg/h。该挤压条件下挤压产品中还原性抗坏血酸的载量15.76%～15.86%,产率大于98%。挤压产品的玻璃化转变温度高于40℃。      

低聚异麦芽糖的生理功能研究

低聚异麦芽糖是一种天然的生理活性物质,具有明显的增殖双歧杆菌的作用。本文主要研究了低聚异麦芽糖的生理功能,为其开发应用提供科学的依据。     

纳滤法去除低聚异麦芽糖中的单糖

研究了纳滤法去除低聚异麦芽糖中单糖的可行性以及纳滤条件对渗透通量和产品糖组分的影响。得出适宜的纳滤操作条件是:温度25～30℃,操作压力为0.7MPa,料液质量分数为10%。纯化10倍时,低聚异麦芽糖的单糖去除率达98.73%。     

低聚异麦芽糖制备的研究进展

低聚异麦芽糖是一种集营养、保健、疗效于一体的功能性低聚糖,在医药、食品、饲料等行业有着广泛的应用,近年来其产量猛增,国内外市场潜力巨大。目前,低聚异麦芽糖主要以淀粉或含淀粉的各类粮食为原料,经多酶协同作用制备而成。主要对低聚异麦芽糖制备方面的研究进行了综述。      

低聚异麦芽糖在面包中的应用

低聚异麦芽糖具有良好的理化性质．如溶解性好、耐酸、耐热、糊精含量低等，同时还具有促进腩道内有益菌群——双歧轩菌等的增殖、预防龋齿等生理功能，是一种集营养、保健、疗效于一身的功能性低聚糖。研究了商品低聚异麦芽糖的部分理化特性，如甜度、耐酸性、耐热性、可溶性固形物、pH值、水分活度等，并探讨了低聚异麦芽糖在面包中的应用用低泉异麦芽糖产品部分代替蔗糖，应用于面包生产中，不仅质量较好，而且可以生产出新的功能性食品．     

低聚异麦芽糖制备的研究进展

低聚异麦芽糖是一种集营养、保健、疗效于一体的功能性低聚糖,在医药、食品、饲料等行业有着广泛的应用,近年来其产量猛增,国内外市场潜力巨大。目前,低聚异麦芽糖主要以淀粉或含淀粉的各类粮食为原料,经多酶协同作用制备而成。主要对低聚异麦芽糖制备方面的研究进行了综述。     

加酶挤压处理玉米淀粉对低聚异麦芽糖产量的影响

采用加酶挤压技术处理玉米淀粉,以挤出产物制备低聚异麦芽糖。以异麦芽糖(IG2)、潘糖(P)、异麦芽三糖(IG3)含量之和作为低聚异麦芽糖产量指标,通过正交试验优化相关参数,确定最优的加酶挤压工艺(挤压过程中挤压温度为95℃,挤压物料含水量为45%,挤压加酶量为0.8%)。通过上述参数进行试验所得的低聚异麦芽糖产量最高可达35%以上。     

含低聚异麦芽糖的传统麦芽糖食品制备

该文对含低聚异麦芽糖的传统麦芽糖食品制备进行研究,分析传统麦芽糖制备过程中麦芽淀粉酶活性和糖化温度对糖化过程的影响,确定合适的糖化条件。结果表明,在糖化过程中添加适量α-葡萄糖苷酶,可将糖化液中的麦芽糖、葡萄糖、麦芽三糖总量由187.2 g/kg降至79.9 g/kg,同时生成总量为85.1 g/kg的异麦芽糖、潘糖和异麦芽三糖。通过在传统麦芽糖制备过程中添加α-葡萄糖苷酶,催化糖化液中的麦芽糖、葡萄糖、麦芽三糖等转化成低聚异麦芽糖,能够提升传统麦芽糖食品的健康功能。     

响应面法优化木薯淀粉制备低聚异麦芽糖工艺

在单因素试验的基础上,选取真菌α-淀粉酶酶量、β-淀粉酶酶量、普鲁兰酶酶量、糖化转苷温度、糖化转苷pH、α-转移葡萄糖苷酶酶量6个因素为自变量,异麦芽糖、潘糖以及异麦芽三糖之和为响应值,采用响应面法优化木薯淀粉制备低聚异麦芽糖工艺中的糖化和转苷工艺.利用Design Expert软件进行模型预测以及响应面分析.优化后工艺:温度为41.9℃,pH 5.45,α-淀粉酶酶量为30.60 U/g(淀粉)、β-淀粉酶酶量为1.04U/g(淀粉)、普鲁兰酶酶量为1.10 U/g(淀粉)和α-转移葡萄糖苷酶酶量为0.48 U/g(淀粉).经试验验证,在此工艺条件下异麦芽糖、潘糖以及异麦芽三糖总和为0.417 2 g/g(淀粉),与预测值的相对误差为0.48％.     

低聚异麦芽糖的应用开发

低聚异麦芽糖不仅具有某些糖类的性质，而且具有防龋齿、增殖双歧杆菌等特殊的保健功能，对其开发并在食品、调味品、饮料、冷饮中应用，有着广阔的市场前景。     

Encapsulation of EPTC in Starch by Twin-screw Extrusion

A twin-screw extruder was used for encapsulation of the herbicide EPTC (S-ethyl dipropylcarbamothioate) in starch. Three starch/water ratios, 35/65, 50/50, and 65/35, were evaluated for efficiency to encapsulate 13.9% EPTC on a dry starch basis. Analysis of extrudates, after drying and grinding to the desired particle size, showed recovery of active ingredient (a.i.) and effectiveness of encapsulation to be best at 35% starch solids (35/65 starch/water ratio). Scanning electron micrographs showed smaller and a more even distribution of a.i. at 35% starch. Suspending particles in water caused a release of EPTC which increased with agitation and smaller mesh size. Air-dried particles released EPTC more slowly than oven-dried particles of the same mesh range. Particles from extrusion at 35% solids released a.i. more slowly than those from extrusion at 65% solids. The slowest releasing particles showed the least swellibility. EPTC was also encapsulated at 10.2% a.i. using 20% and 35% starch solids with steam-injection cooking followed by Sigma blade mixing for comparison with an extrusion. Herbicide retention and encapsulation were superior, release of a.i. into water was slower, and swelling of particles was less in twin-screw extrusion prepared products.     

Lipid Encapsulation in Glassy Matrices of Sugar-Gelatin Systems in Freeze-Drying

Entrapment of lipid in glass forming matrices in freeze-drying was investigated. Dispersion of lipid in aqueous solutions of three different sugars was formed by addition of protein and using homogenisation process. Two different levels of proteins in the ratios of 9:1 and 8:2 (sugar:protein) were used. Three different homogenisation processes were used to vary the emulsion droplet size of dispersed lipid. A novel ultra high-pressure homogenisation treatment with pressure levels up to 255 MPa (5MPa in second stage) was used to form emulsion before freeze-drying. The non-fat solids formed a glass in freezing which led to entrapment of dispersed oil. Ultra high-pressure homogenisation at pressure levels higher than 155 MPa caused alterations in emulsifying properties of sugar/gelatin systems. Changes in emulsifying properties of encapsulation matrices affected entrapment of dispersed lipid components. Droplet size of the dispersed phase was a significant factor for encapsulation efficiency. Emulsions with smaller droplet diameter gave higher entrapped amounts of lipid than emulsions with larger droplets. The glass forming properties and physical state of freeze-dried matrices were also determined. Knowledge of glass forming properties of an encapsulation matrix is needed for entrapment and predicting the stability and release properties of entrapped components.     

RP -HPLC 测定果汁类饮料中抗坏血酸含量

目的：建立果汁类饮料中抗坏血酸(VC)含量的HPLC 检测方法。方法：采用Luna C18(2)色谱柱(150mm× 4.6mm,5μm);流动相：0.1% 草酸溶液,流速：1ml /min;检测波长：245nm,柱温：30℃。结果：峰面积(Y)与浓度(X)在3.952～79.04μg/ml 范围内线性关系良好(r＝0.9999),3倍和10倍信噪比最小检出限为0.0007μg/ml和0.0022μg/ml,平均加标回收率(n=5)为108.3%。实验精密度(RSD)为0.54%,重复性实验RSD 为0.28%,样品8h 内检测结果稳定,日间测定RSD 为5.59%。结论：该方法具有准确、简便、快速的特点,可用于果汁中VC含量的快速检测。     

用库仓滴定法测定食品中抗坏血酸的研究

<正> 众所周知,抗坏血酸是人体不可缺少而又不能在人体中合成的一种维生素,抗坏血酸参与机体的代谢过程,可帮助酶将胆固醇转化为胆酸而排泄,减慢毛细管的脆化,增强机体的抵抗能力,而且抗坏血酸还可用来治疗多种疾病。前人已利用各种方法来测定抗坏血酸的含量,这些方法是用于测定还原型抗坏血酸的2,6—二氯靛酚滴定法,用于测定抗坏血酸总量的2,4—二硝基苯肼比色法,荧光测定法,改良染料法,以及库仓滴定法。但前人所     

紫外分光光度法测定维多康中维生素C的含量

目的:建立紫外分光光度法直接测定维多康中维生素C含量的方法。方法:以Cu2+为催化剂加速维生素C的氧化,以EDTA络合校正背景作参比,利用氧化前后吸光度差值(△A)直接测定维生素C的含量。测得还原型维生素C在265nm处有最大吸收峰。结果:维生素C的浓度在30～70μg/ml范围内吸光度与浓度呈良好的线性关系r=0.99922(n=5),回收率在105.77%～109.50%之间。结论:操作简单,测定快速,结果准确,精密度高,检测范围大,适合于维多康中维生素C的含量测定。     

Inhibition of Mushroom Polyphenoloxidase by Ascorbic Acid Derivatives

Ascorbic acid (AA), dehydroascorbic acid (dehydroAA), isoascorbic acid (isoAA), ascorbic acid-2-phosphate (AA-2- PO₄), and ascorbic acid-2-sulfate (AA-2-SO₄) were tested as inhibitors of mushroom polyphenoloxidase (PPO). Kinetic analysis indicated that AA and isoAA were more effective than dehydroAA. The half times (t_1/2) that decreased 50% of PPO activity for AA, isoAA and dehydroAA were 2.5, 3.1, and 1.9 hr, respectively, and the concentrations that inhibited half of PPO activity were as follows: ascorbic acid, 0.04 mM, isoAA, 0.25 mM; and dehydroAA, 7.5 mM. Electron spin resonance studies demonstrated that the Cu²⁺ of PPO was reduced to Cu⁺ by AA. AA-2-PO₄ and AA-2-SO₄ were not inhibitors for PPO. However, the digestion of AA-2-PO₄ with acid phosphatase yielded AA to inhibit PPO activity. AA-2-SO₄ was found to be a poor substrate for sulfatase.     

吸光光度法标定抗坏血酸标准溶液

本文报道了标定抗坏血酸标准溶液的新方法。实验结果表明,在酸性条件下,KIO_3能严格定量地转变成I_2,I_3~-的最大吸收波长在287nm处,用722型光栅分光光度计测定,最大吸收波长为352nm,于287nm和352nm处,I_3~-的摩尔吸光系数为—4.11×10~4L/mol·cm和2.57×104L/tool·cm;I_3-的吸光度随抗坏血酸加入量的增大在一定深度范围内遵守Beer定律;与滴定法比较,标定结果的符合率分别为97.4～104.8％和98.4～102.9％;重复测定的变异系数分别为1.060％和1.08％。本法标定抗坏血酸溶液,具有灵敏、简便、准确、快速等特点。     

抗坏血酸对小麦多酚氧化酶活性抑制的研究

小麦多酚氧化酶(PPO)是导致面粉及其制品颜色发生褐变的主要因素,对其活性及所催化的氧化-还原反应的抑制将有利于改善小麦食品的外观品质。通过研究26个小麦品种(分别含高、中、低活性)的PPO活性及抗坏血酸(Vc)对其抑制作用,结果表明,全麦粉中加入0.2%(W/W)Vc即可有效抑制PPO活性及其催化的氧化-还原反应,和对照相比,活性降低40.1%~100%;当Vc含量增加至0.4%时,在所有的试验材料中,几乎检测不出PPO活性。Vc对PPO活性抑制的稳定性和持续性研究表明:加入0.6%Vc,在7h的反应时间里,小麦籽粒PPO活性面积(活性曲线下包含的面积)远低于对照,其活性始终处于较低的水平。上述说明Vc对PPO的抑制作用是显著的,这将有利于改善面粉及其制品的色泽。     

Pigment Stability Improvement in Beef Steak by Ascorbic Acid Application

The effect on meat color of spreading a vitamin C solution on the surface of fresh beef longjssimus was studied during 16 days of illuminated display at 4°C. The meat treated with 10% vitamin C solution at 0.1 mL solution to 20g meat had lower metmyoglobin and higher oxymyoglobin than the control after 4 days of display. Vitamin C treatment delayed metmyoglobin formation for 3 days compared to the control.     

高锰酸钾滴定法快速测定蔬菜中抗坏血酸含量

研究快速测定蔬菜中抗坏血酸含量的高锰酸钾滴定新方法.基于KMnO4能在室温条件下定量地将抗坏血酸氧化为脱氢抗坏血酸,可在试样被偏磷酸提取后的酸性溶液中,用EDTA掩蔽干扰离子后,直接用KMnO4标准溶液滴定试液中的抗坏血酸,并利用KMn04自身的颜色变化而指示滴定终点.测定结果的相对标准偏差小于1.0%,加标回收率在93.8%～101.2%之间.结果表明,改进后的方法操作简便,测定快捷,干扰小,测定结果与国家标准方法相符,相对偏差均小于2.5%.