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21.
目的建立一种通过检测蜂蜜中砷的含量来鉴别大米糖浆掺假的方法。方法检测并比较大量不同来源的大米糖浆和纯正蜂蜜中砷的含量,同时优化了蜂蜜中砷的检测方法,样品以硝酸-微波消解,电感耦合等离子体质谱(ICP-MS)测定,内标法定量。结果在0~5.0μg/L范围内线性良好,定量限为10μg/kg,10、15和30μg/kg的添加水平的回收率均在83.7%~109.6%之间,相对标准偏差小于5.9%,并确定了蜂蜜中大米糖浆的阳性判定限,砷含量在15μg/kg以上的蜂蜜为大米糖浆掺假蜂蜜。结论该方法前处理简单,结果准确度和精密度高,纯蜂蜜和大米糖浆的中砷的含量差别明显,可用于蜂蜜中大米糖浆的掺假鉴别。 相似文献
22.
Femi O. Oludemi Charles T. Akanbi 《International Journal of Food Science & Technology》2013,48(7):1416-1425
A conductometric analysis of the effect of condensate of peroxides generated during lipid oxidation in an accelerated stability test was adapted to test the hypothesis that total antioxidant capacity of tomato products would sometimes increase during processing and in storage. Tomato pulp blends made from a mixture of tomato (Lycopersicon esculentum var Roma VF), watermelon (Citrullus vulgaris var Babylack) and pineapple (Ananas comosus var Smooth cayennes) were analysed for basic quality profiles of dry matter, Brix, titratable acidity (TTA) and pH, total reducing sugars, Component antioxidants phytochemicals and total antioxidant capacity. The lowest sensory score (overall impression) of 4.80 ± 2.59 was recorded for tomato juice while, blend TWP 111p had highest score of 6.20 ± 1.99. There was significant difference (P < 0.05) in the basic quality profile of the pulp blends except for TTA values (0.37 ± 0.02 to 0.45 ± 0.05) and 2‐Furfurals (2.47 ± 0.03 to 2.71 ± 0.01). The fresh blend of 50% tomato, 25% watermelon and 25% pineapple had the highest total antioxidant capacity of 3.69 ± 0.52 mg 100 mL?1 catechin equivalent. The total antioxidant capacity of the stored pulp increased from 2.95 ± 0.13 to 6.22 ± 0.32 mg 100 mL?1 catechin equivalent in pasteurised TWP 211p blend by 60 days when stored at 40 °C. Total antioxidant status of tomato‐based fruit mix increased during the first 80 days. 相似文献
23.
电机泵在糖厂中长期使用,暴露出许多它本身无法克服的缺陷.用压缩空气替代电机泵作动力源输送液体物料,则可以从根本上杜绝目前糖厂液体输送中的泄露等现象.本文对当前我区糖厂中最先进的风送泵结构作了说明.同时,提出了风送泵在糖厂内进一步推广应用要注意解决的问题,对解决方法作了初步探讨. 相似文献
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25.
Serafim Bakalis & Mukund V. Karwe 《International Journal of Food Science & Technology》1997,32(3):241-253
Velocity measurements inside the screw channels of a co-rotating, self-wiping, twin-screw extruder were carried out. A laser Doppler anemometer (LDA) system was used to measure tangential and axial velocity components in the translational region of one of the screws of a twin-screw extruder. The velocity measurements were carried out using heavy corn syrup at different screw speeds and for two forwards conveying elements differing in their pitch. It was found that velocity profiles in the translational region were substantially affected by the pitch of the screw element, however, screw speed (30–90 r.p.m.) did not have a significant effect on the shape of the velocity profiles. The range of velocity values in a 14 mm pitch screw element was wider than that in a 28 mm pitch screw element. Experimentally measured velocity profiles were compared with predictions of a one-dimensional model, which showed that the model underpredicted the velocity values, for the 14 mm pitch element. 相似文献
26.
废弃菠萝皮中色素的循环超声提取及其抗过敏活性 总被引:2,自引:1,他引:1
用循环超声技术提取废弃菠萝皮中色素,并对所得色素的抗过敏活性进行评价。通过单因素实验和正交实验确定了循环超声提取技术的最佳工艺,即以质量分数80%的乙醇作为提取溶剂,超声功率500W,提取总时间15min。所得色素对光、热、氧化剂、还原剂具有较好的稳定性,其色价是菠萝色素的4倍之多。此外,采用Morgan-Elson法考察了色素的抗过敏活性,IC50=1.159×10-2g/mL。结果表明,采用循环超声技术从废弃菠萝皮中提取色素具有较好的效果,同时发现菠萝皮色素具有一定的抗过敏活性。 相似文献
27.
Aravind Kalambettu Ajith Damodaran Moorthy Tindivanam Vallam 《Journal of Natural Fibers》2015,12(1):39-51
Composites of polyvinyl alcohol (PVA) reinforced with different weight percentages of pineapple leaf fibers (PALF) were fabricated and evaluated for biodegradation by soil burial test and plate test. FTIR analysis indicated the existence of a chemical interaction between PVA and PALF. The water uptake study showed that the composites with higher fiber content displayed high tensile strength and brittleness but possessed lower water uptake potential. In the soil burial test, the composites with low matrix to filler ratios exhibited higher rates of degradation as evident by the associated decrease in molecular weights. Plate test performed using Pseudomonas putida showed that the composites were susceptible for degradation by bacteria. The results of this study indicated that PALF-reinforced PVA composites were completely biodegradable and could find potential applications in industries such as agriculture and packaging and safely disposed after use without causing environmental damage. 相似文献
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29.
钙和褐变抑制剂对鲜切菠萝影响的初步研究 总被引:3,自引:0,他引:3
研究的目的是筛选对鲜切菠萝颜色和硬度有重要影响的因子。试验采用正交设计,使用浓度为0%和0.5%的异抗坏血酸钠、柠檬酸、六偏磷酸钠、EDTA和氯化钙溶液浸泡菠萝扇片3分钟,振干表面溶液后用聚苯乙烯塑料托盘装(每盘5片,每片约25g)并用PVC膜包扎密封,在10℃下贮藏7天;分别在处理后的第1天和第7天测定菠萝片的L*、a*、b*和硬度。结果表明,在α=0.05水平下,只有异抗坏血酸钠显著抑制L*、a*、b*值的变化;所有5种试剂对鲜切菠萝硬度的影响均不显著。 相似文献
30.
Analysis of cooling curve to determine the end point of freezing 总被引:1,自引:0,他引:1
M. Shafiur Rahman Nejib Guizani Mohammed Al-Khaseibi Salim Ali Al-Hinai Salha Saleh Al-Maskri Khalid Al-Hamhami 《Food Hydrocolloids》2002,16(6):111
The cooling curve method used for the measurement of freezing point of food is further analyzed to explore whether it can be used to identify the end point of freezing or glass transition. In this method, slope of the cooling curve is determined and plotted as a function of time to identify the end point of freezing (T′m). Initially, the slope is decreased and then reached a minimum value, which is identified as the nucleation of ice. Then the slope is increased until the end point of freezing. The end point of freezing is identified when the slope starts to decrease from its highest value or plateau. Sucrose solutions and starch gels were used to measure its T′m in identifying validity of the proposed method. The measured values of T′m by the proposed method is very close to the literature values. 相似文献