黄檗果实精油的化学成分、抗氧化及细胞毒活性研究

采用水蒸气蒸馏法提取黄檗果实精油,利用气相色谱-质谱联用技术(GC-MS)对其成分进行分离鉴定;通过DPPH自由基清除作用和β-胡萝卜素漂白法检测精油的抗氧化活性,应用磺酰罗丹明B(SRB)比色法检测精油对人宫颈癌细胞He La、人肺癌细胞A-549和人胃癌细胞BGC-823这3种肿瘤细胞株的细胞毒活性。经GC-MS分析,从黄檗精油中共鉴定出39个成分,主要有β-蒎烯、β-氧化石竹烯、3-亚甲基-4-异丙烯基环己醇、西松烯等。精油具有一定抗氧化活性,对肿瘤细胞株A-549和BGC-823的细胞毒活性不显著,但对He La细胞具有较好的细胞毒活性。     

ZTC1＋1天然澄清剂在桑叶多糖提纯中的应用

考察Ⅱ型ZTC1＋1天然澄清剂在桑叶多糖提取中的提纯效果。以硫酸-蒽酮法测定多糖含量,通过正交试验优化天然澄清剂处理工艺。试验表明Ⅱ型ZTC1＋1天然澄清剂能有效地保留桑叶中的有效成分多糖。适宜工艺条件为药液浓缩程度为5mL／g,澄清剂B和A两组分的加入量分别为浓缩药液体积的2％和1％,絮凝温度50℃。在此工艺下,多糖保留率为96％,浸膏中多糖含量约为22％,蛋白去除率约为16％。     

蔬菜水果中硝酸盐与亚硝酸盐的测定及其储藏过程中的含量变化

文章采用离子色谱法/电导检测器,测定了蔬菜水果样品中的硝酸盐和亚硝酸的含量。实验选取并优化样品前处理方法,获得无色透明的溶液后,经0.45μm过滤器过滤后得到待测液,最后自动进样,离子色谱法进行样品测定,以10 mmol/L KOH溶液为淋洗液,相对标准偏差：NO3-为0.38%,NO2-为0.54%;回收率：NO3-为98.8%～99.7%,NO2-为98.6%～99.9%。本方法操作简便快速,且具有仪器稳定性好、测定结果准确可靠的特点。在被测定蔬菜水果中,硝酸盐和亚硝酸盐含量都在较低浓度水平,NO3-：16.8～21.9 mg/kg,NO2-：0.0887～0.164 mg/kg。最后讨论了几种蔬菜水果样品储藏过程中硝酸盐与亚硝酸盐的含量变化情况。     

桑椹酒质量安全控制技术研究进展

桑椹酒酿造技术难度高,主要是挥发酸、甲醇、杂醇油含量的控制以及风味、色泽、澄清度等品质的提升。该文通过原料品质、酵母、工艺、原酒存储等方面综合调控从而抑制挥发酸含量的升高;通过原料采收管理、去渣发酵、酵母菌选用、控温发酵等措施控制甲醇含量升高;通过无机氮源和低产杂醇油酵母的应用,以及低温发酵等技术将杂醇油含量控制在较低水平;通过抗病品种选育、合理防治避免桑椹酒农药残留较高。该综述对现阶段桑椹酒酿造关键技术研究进行总结,探讨桑椹酒发酵过程中挥发酸、甲醇、杂醇油含量、农药残留的影响因素及控制措施,为桑椹酒产业化生产提供参考。     

水果香气物质分析研究进展

香气是水果及其产品最重要的质量指标之一.保持天然风味、改善香气以及提高产品品质一直是行业追求的目标,这使得准确全面分析水果中的香气物质至关重要.由于水果基质复杂,香气化合物含量低,特别是一些关键香气物质极微量或不稳定,所以对水果香气成分的准确分析是一项复杂且困难的工作.简述了水果香气物质的提取方法和目前水果香气物质研究...     

李果采后生理及贮藏保鲜技术研究进展

李果品种繁多,具有较高的营养价值和经济价值而深受消费者喜爱,但由于其成熟期大多在5～8月高温季节,采后生理活动旺盛,这给鲜食李果贮藏保鲜带来极大困难.因此,探明李果采后生理变化规律与机制,并对其贮藏保鲜技术进行研究与开发是改善李果采后品质和延缓衰老的有效途径.文章从李果采后生理变化及贮藏保鲜技术方面综述了近年来的研究进...     

A simple preparative method for isolation and purification of polysaccharides from mulberry (Morus alba L.) leaves

An effective method for preparative extraction and purification of the polysaccharides from mulberry leaves was studied. Orthogonal experiment was carried out to get the optimal conditions (T = 70 °C, pH = 6, t = 60 min, D = 0.4 g g^?1 material) of activated carbon decolorisation. The staged, isocratic and multiple ethanol precipitation procedures were also investigated. Through the activated carbon decolorisation and 20% ethanol precipitation procedure, the polysaccharides yield reached 2.91%, and the content of neutral sugar and uronic acid were improved to 21.87% and 57.43% respectively. This process was superior to the macroporous resin adsorption and gel permeation chromatography (GPC) methods. The structure analysis indicated that the purified mulberry leaves polysaccharide (MLP) was composed of Man, GalA and Rha in the ratio of 1.0:7.2:20.0. The molecular weight measured using GPC was approximately 557 062 D. The IR and ¹H NMR spectra indicated that the MLP was mainly pectin, which was classified as high‐methoxyl pectin.     

Equilibrium Sorption Isotherms and Isosteric Heat of Rose Hip Fruits (Rosa Eglanteria)

For sorptional data to be useful in simulation and design purposes, they must be represented by equations valid in the conditions usually found in industrial practice. In this regard sorptional models that include the influence of temperature on desorption and sorption equilibrium values are most valuable. In this article, water desorption and sorption isotherms of rose hip fruits (Rosa Eglanteria) were experimentally determined by the gravimetric method, and from these the isosteric heat of sorption was calculated. According to the ANOVA test carried out for this fruits, no significant differences were found between experimental desorption and adsorption isotherms. Seven models were tested to mathematically represent the moisture content as a function of water activity (a_w) in the a_w range of 0.11 to 0.85 and temperatures of 20, 40, and 60°C, for further use in process simulation.

The five-parameter GAB model was most accurate, with an MRE of ?2,9 % and R²?=?0.989. The values obtained for the isosteric heat of sorption were fitted with a previous published equation, with an MRE%?=??0.05. The isosteric heat of sorption derived from the GAB five parameters equation, for the corresponding monolayer moisture content, only differed by 1.25% with the calculated in this paper.     

气调贮藏果蔬品质的影响因素分析

从果蔬的营养成分、硬度和呼吸作用等指标对果蔬的品质进行了分析;介绍了当今贮藏效果最佳的气调贮藏技术,它通过调节环境的气体成分使得果蔬的呼吸作用减弱,以降低营养成分的消耗,保持果蔬的营养价值和新鲜品质;研究发现,贮藏条件对果蔬品质的影响很大,保证果蔬品质的良好必须有适宜的贮藏条件,贮藏过程中影响果蔬品质的因素有温湿度、空气流速、气体成分、包装和运输等;最后分析了在不同温度、不同时间的贮藏条件下,几种果蔬品质的变化.