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壳聚糖涂膜保鲜杨桃的研究 总被引:2,自引:2,他引:0
研究了不同组成的壳聚糖涂膜保鲜剂对杨桃的保鲜效果。结果表明:壳聚糖涂膜剂对杨桃具有较好的保鲜效果,浸涂保鲜剂的杨桃在贮藏期间其水分、总酸和维生素C的含量均高于对照,而还原糖含量低于对照。壳聚糖涂膜保鲜剂较适宜的配方为:壳聚糖2.5%,乙酸1.5%,甘油1.0%,单硬脂酸甘油酯0.3%,水94.7%。 相似文献
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本文采用壳聚糖和茶粉为保鲜剂,以菌落总数、酸价(AV值)、过氧化值(POV值)作为月饼保鲜评价指标,研究月饼在常温保存时的品质变化规律。结果表明,经过壳聚糖涂膜和茶粉添加处理的广式豆沙月饼菌落总数、AV值、POV值均明显低于对照实验组。壳聚糖和茶粉对广式豆沙月饼的保鲜有协同增效作用,最佳保鲜效果的复配组合为:浓度为1. 5%相对分子质量为4 k Da的壳聚糖与浓度为2. 0%相对分子质量为200 kDa壳聚糖的混合配比分别为45%、55%,茶粉添加量为3. 5%。 相似文献
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以壳聚糖为成膜保鲜剂、复配防腐剂山梨酸钾和抗氧化剂抗坏血酸,制成了一种荔枝复合涂膜保鲜剂,考察了其在室温(30~35℃)和低温[(6±1)℃]下对荔枝的保鲜效果。结果表明,与对照相比,无论是室温还是低温贮藏,经由1.0%壳聚糖、0.5%山梨酸钾和1.0%抗坏血酸组成的复合涂膜处理,可以显著抑制荔枝发生褐变,明显降低荔枝果实的失重率,减少可溶性固形物、可滴定酸、维生素C等营养物质的消耗,提高了荔枝的好果率,在室温下可使荔枝在6d内保持100%的好果率,而对照在第2d就只有90%的好果率;低温贮藏20d,对照的好果率仅为20%,而处理组的好果率为100%,低温贮藏30d,处理组的好果率仍高达90%。 相似文献
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壳聚糖用作食品的保鲜剂具有良好的成膜性和强的抗菌保鲜防腐能力,再加上其来源广泛、天然、无毒副作用及涂膜保鲜简单易行等诸多优点,因而受到了国内外的广泛研究。本文综述了以壳聚糖为主要原料的壳聚糖复合物,如壳聚糖-有机酸复合物、壳聚糖-维生素C复合物、碘化复合物、壳聚糖-纳米材料复合物、壳聚糖-CaCl2-乳清蛋白-柠檬酸复合物、钙复合巯基化壳聚糖复合物、壳聚糖稀土复合物在水果防腐保鲜方面的应用,并对壳聚糖复合物的保鲜前景进行了展望。 相似文献
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柠檬酸硬脂酸单甘脂的合成研究 总被引:2,自引:0,他引:2
通过对柠檬酸硬脂酸单甘脂的合成研究 ,确定了以乙酸为催化剂兼溶剂 ,柠檬酸与硬脂酸单甘脂进行酯化反应的最佳工艺路线。结果表明 ,在此工艺路线下的最佳工艺条件为 :柠檬酸与硬脂酸单甘脂的摩尔比为 2∶1,乙酸用量为 10 0 % (以硬脂酸单甘脂质量计 ) ,反应温度为 12 0℃ ,酯化反应时间 3h ,真空度为 0 9MPa。该产品可作为食品乳化剂 ,在食品工业中有广泛的应用前景 相似文献
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疏水型阳离子水性聚氨酯的合成与性能研究 总被引:1,自引:0,他引:1
以甲苯二异氰酸酯,聚酯、聚醚混合多元醇为基本原料,N-甲基二乙醇胺(MDEA)为亲水扩链剂,羟丙基聚二甲基硅氧烷、单硬酯酸甘油酯为改性剂,通过醋酸中和反应制备出疏水型自乳化阳离子水性聚氨酯乳液;研究了改性剂用量、R值(体系中—NCO和—OH的物质的量比)、MDEA含量和中和度对乳液耐水性的影响。结果表明:羟丙基聚二甲基硅氧烷和单硬酯酸甘油酯加入到聚氨酯体系中,均能显著提高聚氨酯的耐水性;胶膜吸水率随MDEA含量增加呈先降低后升高的趋势;当中和度小于100%时,胶膜吸水率随中和度的增大而减小;当中和度大于100%时,中和度对胶膜吸水率无明显影响。 相似文献
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有机硅硬质涂料的制备 总被引:6,自引:4,他引:6
以甲基三乙氧基硅烷和正硅酸乙酯为主要原料,经水解缩合,制得低n(R)/n(Si)值的硅树脂;添加适当的溶剂、固化剂和改性剂等助剂,制得有机硅硬质涂料。讨论了原料配比、溶剂及各种助剂对有机硅硬质涂料性能的影响。结果表明,硅树脂的n(R)/n(Si)值选择0、85,以甲醇/乙醇/异丙醇/乙二醇甲醚为复合溶剂、氨基树脂为耐碱改性剂、三乙酰丙酮铝为固化剂时,制成的有机硅硬质涂料贮存期超过6个月,固化速度快,涂膜硬度高达6H,对有机玻璃的附着力为1级,透光度93.6%,耐碱性良好。 相似文献
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N. H. Kuhrt R. A. Broxholm W. P. Blum 《Journal of the American Oil Chemists' Society》1963,40(12):725-730
Conjoined Crystals is the name given to a new food emulsifier whose special properties are associated with its content of
glycerol monoester in a stabilized α-crystalline form (6). It consists of the mixture of crystals formed by cooling a melt
containing approximately equal molecular proportion of certain long chain fatty acid monoesters of glycerol and of 1,2-propanediol.
A practical composition contains a blend of glycerol monostearate and 1,2-propanediol monostearate.
Conjoined Crystals disperse readily in water and retain this ability for periods of over a year, a property which appears
to be closely associated with their effectiveness in baking and in other applications. This water dispersibility contrasts
with the behavior of the usual modification of glycerol monostearate which is difficult to disperse in water.
Infrared analysis indicated that the major part of the glycerol monoester in the mixed crystals is in the α-crystalline modification.
Studies by X-ray diffraction supported this conclusion. Thus, we have consistently associated ready water dispersibility and
the α-form with the enhanced emulsifying ability.
Communication No. 293. 相似文献
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Mixed crystals of glycerol monostearate and 1,2-propanediol monostearate (propylene glycol monostearate) (a useful composition
of Conjoined Crystals, see Part 1) disperse readily in water, retaining this property for long periods of time. The effect
of composition on retention of the α-crystalline form of the glycerol monoester in such dispersions is discussed.
The water dispersions foam when shaken or when air is blown through the dispersion, a property which appears to be associated
with the superior activity of the mixed crystals as a food emulsifier. A test method for measuring foam retention is described.
The crystals, or their water dispersions, are useful in the preparation of low-calorie, fruit “fluffs,” such as whipped applesauce.
Sponge cakes with fine grain, improved volume, and texture were prepared with the water dispersions. The crystals are effective
emulsifiers in cake mixes and bread. These tests are described.
Communication no. 294 from the Research Laboratories of Distillation Products Industires, Division of Eastman Kodak Co. 相似文献