高浓度果汁加工废水处理工程实例

针对某饮料有限公司生产苹果汁产生的废水,采用水解酸化 接触氧化工艺进行了处理。废水水量:1000m3/d;水质:CODcr≤8000mg/L,BOD5≤4800mg/L,SS≤6000mg/L,pH=4～8。经过处理后,出水水质:CODcr<150mg/L,BOD5<30mg/L,SS<150mg/L,pH=6～9。出水达到《污水综合排放标准》(GB8978 96)中的二级标准。     

酸—酶联用液化法制备小麦淀粉麦芽糖浆的工艺研究

以小麦淀粉为原料,利用盐酸、中温α-淀粉酶共同液化进行麦芽糖的制备。采用单因素实验结合正交实验法优化工艺参数。结果表明:酸—酶联用液化法的最佳工艺条件为:淀粉浆料液比(3∶10),5%盐酸添加量12 mL,酸化时间12 min,温度100℃,浓度为0.0143g/100mL的中温α-淀粉酶加酶量8ml,酶液化时间30 min,pH值5.4,温度64℃,所得液化液DE值为8.12%。通过无机酸与酶法共同液化小麦淀粉得到的液化液DE值控制在具体数值范围内,为以小麦淀粉为原料制备麦芽糖浆的工业生产提供了理论依据,也为下一步对小麦淀粉在板框过滤时出现的困难分析奠定基础。     

超临界萃取技术最佳方法的研究

采用正交试验的方法探讨了压力、温度、CO2流量和堆积密度对五味子提取物收率的影响，确定了超临界CO2五味子提取物的最佳工艺条件．结果证明：CO2流量、压力和温度是最重要的影响因素，最佳的工艺条件为萃取压力30MPa，温度40℃，CO2流量15L／h，堆积密度200g/L，并测定了五味子萃取物中有效成分五味子乙素的质量分数．     

Feasibility Study for Determination of the Dextrose Equivalent (DE) of Starch Hydrolysis Products with Near‐Infrared Spectroscopy (NIRS)

Starch hydrolysis products such as maltodextrin and glucose syrup have many applications in the pharmaceutical and food industry. Several physical and functional properties, for example sweetness, compressibility and viscosity vary according to the extent of starch hydrolysis which is characterized by the dextrose equivalent (DE) value. The Pharmacopoeias use the titrimetric Lane Eynon method with alkaline Fehling's solution for determination of DE. In order to replace this empirical method, near‐infrared (NIR) calibration models for the reagent‐free determination of DE were developed. The maltodextrin model with a DE of less than 20 showed very good correlation with r = 0.97. The correlation of the extended model of maltodextrin and spray‐dried glucose syrup with a DE up to 44 was calculated to be r = 0.99. The NIR method is a very effective, rapid and non‐destructive alternative to the current pharmacopoeial procedure.     

Distribution of aflatoxins in product and by‐products during glucose production from contaminated corn

Afllatoxins are known to be hepatotoxic, carcinogenic, and teratogenic. A positive correlation has been established between the consumption of aflatoxin‐contaminated foods and the increased incidence of liver cancer worldwide. A survey of Egyptian corn and corn‐based products and by‐products shows that the majority of the samples had higher limits of aflatoxin. We have conducted experiments to determine the fate and distribution of aflatoxin during wet‐milling process fractions and investigate the aflatoxin destruction during starch conversion to glucose syrup. The present results showed that about half of the aflatoxin content (48.1%) in the infected corn grain was found to be lost in steep liquor, depending upon the aflatoxin type, arranged in the order G₁ > G₂ > B₁ > B₂. After wet‐milling aflatoxins were distributed into starch, gluten, fiber, and germ. Gluten, fiber, and germ were the most highly contaminated fractions. The loss of aflatoxin during process of starches reached 54.4% in steep water and water process. Although the gluten fraction represents only 9.6% of corn, the higher percentage (25.3%) of aflatoxin was found in this fraction, the fiber and germ account for nearly 29% of the milled corn and contain 11.6% of the aflatoxin. On the other hand, 8.7% of the total aflatoxins in start corn was found in starch fraction which accounts 61% of the milled corn. Aflatoxins G₁ and G₂ were found lost in higher concentrations compared to the aflatoxin B₁ and B₂. A higher percentage of AfG₁ (86.35%) and AfG₂ (78.36%) and a lower percentage of AfB₁ (16.3%) and AfB₂ (14.7%) were found in starch fraction. The conversion percent of contaminated starch was 89.5% compared with control starch. It can be concluded that aflatoxins were destroyed during starch conversion. Consequently, glucose syrup produced from contaminated starch was found aflatoxin‐free.     

果葡糖浆对焦糖色素质量影响的研究

本文利用双酶法生产的果葡糖浆(DE值相同、果糖和葡萄糖含量不同)制作焦糖色素,在相同制备工艺下,对焦糖色素的吸光度进行了比较.发现相同的DE值条件下,果糖和葡萄糖含量越高,吸光度就越大;果葡糖浆的DE值越高,吸光度也越大.     

果葡糖浆在果汁饮料中的应用研究

对使用蔗糖与果葡糖浆生产的果汁饮料的成分进行了分析，比较了两类产品的糖成分和感官差异。结果表明：使用蔗糖生产的果汁饮料与使用果葡糖浆生产的果汁饮料比较，果葡糖浆对产品色泽的影响与蔗糖没有明显区别；但在产品风味方面，后者甜味消失快，果香味与酸味变浓；在果汁生产过程中，采用果葡糖浆部分替代蔗糖的产品风味不受影响．     

蓝柑风味糖浆货架期预测模型的建立与评价

本文主要阐述了蓝柑风味糖浆货架期预测模型的研究过程及方法,对蓝柑风味糖浆储存过程中多维度品质变化、保藏期限等进行评估预测。在4、27、37 ℃的贮藏条件下,通过对感官指标、可溶性固形物含量、pH、还原糖含量、羟甲基糠醛（5-hydroxymethyl-furfural,HMF）等多项指标变化的逐一分析,结合动力学模型和Arrhenius方程,完成了货架期预测模型的构建。结果表明,以感官得分为80分、可溶性固形物含量为85%、pH为2、还原糖含量为100%、羟甲基糠醛含量为35 mg/kg作为蓝柑风味糖浆货架期的终点,在4 ℃冷藏条件下,蓝柑风味糖浆的理论货架期约为48个月;20 ℃室温条件下,蓝柑风味糖浆的理论货架期约为24个月,货架期终点蓝柑风味糖浆的品质出现不可接受的损失。蓝柑风味糖浆货架期预测模型的建立,为糖浆类产品货架期预测建模提供了新思路。     

薄层色谱法测定蜂蜜中高果糖淀粉糖浆

为了鉴定蜂蜜的品质,将1g待测蜂蜜样品溶液在活性炭—硅藻土柱上进行净化和分离,其中由淀粉转化而成的高分子糖经富集、浓缩,再用薄层色谱法分离、显色.同时采用同一方法对3个对照样品溶液(纯蜂蜜、含5％糖浆蜂蜜、含10％糖浆蜂蜜)进行监测,观察Rf值小于0.35的区域斑点排布情况,纯蜂蜜只在Rf值大于0.35的区域呈现蓝色斑点,而含有5％、10％糖浆蜂蜜则在Rf值小于0.35的区域出现不同深度的斑点群,含有糖浆越多则斑点群出现的位置越接近起点,颜色也越深.此法是定性实验,检出限为5％高果糖淀粉糖浆.     

重组高异构化率葡萄糖异构酶酶学性质的研究

葡萄糖异构酶催化D-葡萄糖形成D-果糖的异构化反应，是工业上制备高果糖浆的关键酶。介绍一种新型重组葡萄糖异构酶（rGI）的酶学性质。rGI的最适作用温度为90℃～100℃，最适作用pH为7．0。rGI具有较好的热稳性，90℃下的酶活半衰期约为5h。rGI酶活表达依赖二价金属离子。在90℃、pH7．0和5h下，rGI异构化30％（w／v）葡萄糖液为果糖的异构化率达到54．8％。