高效液相色谱法测定麦精中的低聚糖

采用高效液相色谱法对麦精中的纤维三糖和纤维四糖进行了定量测定研究,最终确定的最佳分析方法为CarbomixH-NP10:5%分析柱;示差折光检测器55℃柱温;流动相:2.5mmol/LH2SO4水溶液;流速:0.5mL/min;进样量:20μL。该方法精密度RSD<2%,回收率>97%。在此色谱条件下15min内完成了三糖和四糖的分离,结果比较理想。研究表明此新建方法准确而快速,并能适用于绝大部分食品中低聚糖的测定。     

陶瓷膜微滤制备食用级浓缩磷脂的研究

用无机陶瓷膜微滤饲料级大豆磷脂-正己烷混合溶液制备出了杂质含量少、透明程度高的食用级浓缩磷脂。研究了膜孔径、压力、料溶比、温度与膜通量的关系以及不同膜孔径、溶料比、温度对磷脂丙酮不溶物含量、正己烷不溶物含量的影响。实验表明,在40℃,0.20MPa压力下,饲料级浓缩磷脂与正己烷质量比为1∶3的混合溶液用1.2μm孔径陶瓷膜微滤,初始膜通量为110L/(m2·h),微滤后产品中丙酮不溶物含量和正己烷不溶物含量分别为60.20%和0.0082%,符合食用级浓缩磷脂的要求。     

Identification of optimal membrane morphological parameters during microfiltration of mosambi juice using low cost ceramic membranes

In this work, experimental investigations were carried out for the identification of optimal membrane morphological parameters (pore size distribution, average pore size and porosity) during microfiltration (MF) of mosambi juice using low cost ceramic membranes. Four different low cost ceramic membranes with different pore diameters (d_m) and porosities (?) were subjected to MF studies to evaluate the effect of d_m and ? on permeation characteristics (permeate flux and juice quality) of centrifuged mosambi juice (CJ) and enzyme treated centrifuged mosambi juice (ETCJ). Subsequently, a convenient factor namely effective permeable area factor (?_md_m²) was evaluated to provide greater insights in the fouling phenomena. Various physio-chemical properties such as colour, clarity, pH, citric acid content, density, total soluble solid (TSS) and alcohol insoluble solids (AIS) were measured for both feed and permeate juice samples to evaluate the effect of ?_md_m² on juice quality. Typical permeate fluxes were observed to vary from 5.78 × 10⁻⁶ to 13.45 × 10⁻⁶ m³/m² s for CJ and 14.07 × 10⁻⁶ to 60.64 × 10⁻⁶ m³/m² s for ETCJ at 82.7 kPa (ΔP) for different membranes whose ?_md_m² varied from 0.249 to 0.783 μm². Among different membrane pore blocking models, flux decline by cake filtration was found to be the best fitted model. The cake filtration model constant (k_c) was found to vary with ΔP and ?_md_m² and was empirically correlated. Phenomenological models were proposed to illustrate the dependency of total hydraulic resistance of membrane on ?_md_m², ΔP and time (t). Based on experimental as well as theoretical investigations, membranes with ?_md_m² up to 0.443 μm² for CJ and 0.294 μm² for ETCJ and a ΔP of 82.7 kPa were recommended for MF of mosambi juice.