大豆蛋白超滤中的膜污染与清洗方法的研究

阐述了超滤膜污染机理及其影响因素,针对中空纤维超滤膜处理大豆蛋白所引起的膜污染问题,提出了预防措施,对不同清洗方法和清洗剂的清洗效果进行了研究,试验证明物理清洗和化学清洗相结合可有效地提高超滤膜的再生效果,不同清洗剂的清洗效果有显著差别,其中使用复合清洗剂（高锰酸钾和蛋白酶）的清洗效果最佳,其超滤膜的透水恢复率可达新膜透水率的96%以上。     

EFFECTS OF INTERMOLECULAR INTERACTIONS AND MOLECULAR ORIENTATION ON THE FLUX BEHAVIOR OF XANTHAN GUM SOLUTIONS DURING ULTRAFILTRATION

Conformational changes of xanthan gum as a function of concentration were investigated to elucidate its unusual flux behavior during ultrafiltration (UF). The contribution of hydrogen bonding on structure formation and the molecular orientation of xanthan gum on the flow characteristics were studied rheomechanically and rheo-optically. Known to affect xanthan structure at low concentrations, hydrogen bonding unexpectedly did not show significant influence on xanthan rheological properties up to 2 wt %. The ordered layers formed on the membrane surface proved responsible for the enhanced water removal during UF. This unique behavior could be attributed to the formation of aligned molecular orientation in addition to the viscosity increases during the biphasic region. Significant differences were observed between xanthan fermentation broth and solutions made of commercial xanthan, suggesting the need to control the salt concentration in fermentation broth in order to make UF an effective recovery process for xanthan gum after fermentation.

PRACTICAL APPLICATIONS

The knowledge gained from the present study strengthens fundamental understandings on the conformational changes of xanthan biopolymers during the recovery of xanthan gum from fermentation broth using ultrafiltration (UF). By taking advantage of the aligned molecular orientation, along with controlling the salt concentration in the fermentation broth, UF could be operated at elevated flux to speed up the removal of water from the viscous fermentation broth. The technology should find broad applications in the fermentation industry, especially where viscosity is of concern during the separation and purification of the product.     

超滤法与吸附法对茶饮料澄清作用的比较

将超滤法与吸附法对茶饮料的澄清作用进行了比较，证明不论是保留茶的有效成分还是澄清效果，二者均匀有显著差异（Ｐ〈０．０５或Ｐ〈０．００１），超滤法明显优于吸附法。     

RETENTION OF SPARINGLY SOLUBLE VOLATILE COMPOUNDS DURING THE FREEZE DRYING OF MODEL SOLUTIONS

The retentions of terpenic essential oil components (carvone, pulegone and piperitone) and non-terpenic essential oil components (eugenol and m-anisaldehyde) were measured during the freeze drying of model aqueous solutions. Model solutions contained sucrose, glucose, sodium chloride or gum arabic which are all common food components. The percent retentions of these slightly soluble flavoring compounds were found to increase with increased initial solids concentration, decreased initial volatile content, increased sample thickness, increased freezing rate and the absence of an additional sparingly soluble volatile.     

茶的起源与饮料加工

本文简述了茶的起源及其营养成份对人体的作用，并对茶饮料加工工艺进行了初步研究。确定了茶饮料生产的工艺条件，为工业化生产提供了技术保证。     

ULTRAFILTRATION OF WHOLE MILK WITH HOLLOW FIBER MEMBRANES

Whole milk was concentrated using Romicon PM50 membranes. Rententate and permeate were analyzed for total solids, protein (TKN) and fat at five concentration levels. The effects of pressure, concentration, fiber length and several milk pretreatments on flux were examined. A 5X concentrate was prepared containing 37.2% solids, 13.3% protein and 17.8% fat. The highest initial and 4X fluxes were obtained using a pressure differential of 1.4 kg/cm² - 2.11/0.7 (20 psig - 30/10). Flux declined slowly with concentration to 3X (20% loss) and decreased more rapidly thereafter. Higher fluid velocities were deemed responsible for 27% higher initial flux and 47% higher 4X flux when a shorter module was employed (63.5 versus 109.2 cm). Clarification, pasteurization and/or homogenization had little effect on flux at either level.     

碧螺春茶在贮藏过程中的品质劣变及生化成分与感观品质的相关性研究

本文研究了碧螺春茶在贮藏过程中主要生化成分（含水量、咖啡碱、氨基酸、总糖、叶绿素、茶多酚、水溶性物质和抗坏血酸）的劣变趋势及感官审评的变化情况,采用多元线性回归对其二者做了相关性研究,结果如下：在碧螺春茶品质劣变过程中,抗坏血酸的氧化程度与碧螺春茶的感官品质劣变程度关系最为密切,其相关性达到了0.992（P＜0.01）;通过抗坏血酸的氧化情况可以大体得出碧螺春茶劣变程度,并且存在如下关系：y（品质得分）=32.447＋305.390x（抗坏血酸）.     

雪莲果的化学组分及其功能特性

雪莲果是原产于安第斯山的一种块茎水果，近几年来由于其特殊的功能性成分得到世界的关注。主要介绍了国外对雪莲果块茎及其叶子的化学组分和功能特性的研究进展。研究表明：新鲜雪莲果的块茎中含有干基的45％～65％的低聚果糖，低聚果糖不仅热量低，还是有效的双歧杆菌增殖因子；另外，雪莲果叶中富含丰富的酚酸成分，具有抗氧化的作用，对糖尿病有着显著的疗效。     

SPINNING DISC MEASUREMENT OF TWO-STAGE CLEANING OF HEAT TRANSFER FOULING DEPOSITS OF MILK

The efficient and effective cleaning of milk protein – based deposits from heat transfer equipment is essential in the dairy industry. The aim of this study was to evaluate the effectiveness of two‐stage cleaning using acid and caustic. Stainless steel discs were fouled during heat transfer by skimmed milk and whey protein. The discs were then cleaned with acid and sodium hydroxide solutions under controlled mass transfer conditions using spinning disc techniques. The use of 0.5% nitric acid, and a commercial acid known as Triplex, as a rinse before caustic cleaning increased the cleaning rate by 2.5 times. The foulant was found to swell about 40% and calcium was leached out within 5 min after exposure to acid. The acid treatment is believed to cause a reduction in the viscosity, and hence an increase in dissolution, of the gel layer formed when caustic cleaning takes place.