膜技术在处理大豆乳清废水中的应用

大豆乳清废水经预处理后,采用超滤膜技术回收含低聚糖废水中的乳清蛋白,再用纳滤膜脱盐、浓缩低聚糖,滤液过反渗透膜即可达到回用或排放要求。探讨了预处理工序的必要性,考察了不同型号膜的运行情况并进行了选择。实验证明,该工艺简单、节能、易操作,污水零排放,且回收产品质量有较大提高,中试数据可供工业化参考与借鉴。     

干酪乳清蛋白膜回收技术及膜污染问题研究进展

随着乳清蛋白较高的生理活性和理化特性不断被发现,并且广泛的应用于食品生产中,乳清蛋白的高效回收技术也越来越受到全球食品领域的关注。膜技术的出现使乳清蛋白的高效快速回收成为可能,但膜污染问题所带来的相对较高的回收成本制约着膜回收乳清蛋白的广泛推广。然而在乳清蛋白膜回收过程中,影响膜污染的因素十分复杂。该文从膜材料和膜回收工艺在乳清蛋白回收中的应用进行综述,此外对导致乳清蛋白回收过程中的膜污染机制进行了综合分析,为今后乳清蛋白膜回收技术的创新提供理论基础。     

Characterization of four new Lactococcus lactis bacteriophages isolated from dahi whey

Four lytic phages of Lactococcus lactis ssp. diacetylactis isolated from indigenous dahi whey were examined for their stability, growth characteristics and morphology. All these phages were partially inactivated by CHCl₃ , remained stable at 40°C and were partially inactivated at pH 3. There was a marked difference among these phages with respect to latent period, rise period and burst size. All phages belonged to Bradley's group B.     

Dairy bacteriophages isolated from whey powder: Thermal inactivation and kinetic characterisation

Fifty three bacteriophages of three lactic acid bacteria species (i.e., Lactococcus lactis, Leuconostoc pseudomesenteroides, Streptococcus thermophilus) isolated from whey powders and whey powder formulations, were tested for their thermal stability. Complete inactivation of Ln. pseudomesenteroides and S. thermophilus phages required 1 min heating at 85 °C and 90 °C, respectively. L. lactis phages exhibited the highest heat resistance and 16% of them were still detectable after heat treatment at 95 °C for 1 min. The most thermo-resistant phages of L. lactis (P956), Ln. pseudomesenteroides (P973) and S. thermophilus (P1008) were selected to determinate their kinetic parameters and lines of equal effects for 9-log inactivation. High D-values of 105 min (phage P956), 74 min (P973) and 25 min (P1008) were determined for thermal treatments at 75 °C, confirming previous findings that pasteurisation conditions are insufficient for adequate inactivation of thermo-resistant dairy phages.     

膜技术在乳清粉综合利用中的应用

提出了用超滤膜、电渗析膜、反渗透膜技术分离乳清蛋白,提纯乳糖的新工艺.采用超滤膜分离大分子乳清蛋白.用电渗析膜分离法除去乳糖中的杂质离子,用反渗透膜除去大量水分.分离后的产物,经浓缩、干燥得到乳清浓缩蛋白(WPC)及高纯度的乳糖,试验取得了比较满意的结果.与现行工艺相比,污染少、能耗底、收率提高,使生产成本显著下降,该工艺具有良好的开发前景.     

膜分离技术及其在乳品工业中的应用

对膜分离技术的分离特征、分类、应用范围进行了介绍,同时从理论上阐述了膜分离技术在乳品除菌、乳蛋白质的分离浓缩、分离脂肪、乳清脱盐、牛奶浓缩、乳品标准化及乳品生产企业废水回收等方面的应用。     

乳清中棉籽蛋白的超滤回收研究

采用超滤技术回收蛋白质沉淀后的乳清中的棉籽蛋白,考察了操作压力、超滤时间、温度、pH、蛋白质浓度等因素对超滤膜通量的影响。结果表明,在等电点处膜通量最低,故超滤操作应在偏离蛋白质等电点的条件下进行;在实验范围内膜通量随操作压力的升高而升高,呈线性关系;随着超滤时间的延长,膜通量逐渐减小,超滤进行至20~30 min后,膜通量趋于稳定;随着温度的升高,膜通量增加。     

Buffering curves of ideal whey fractions obtained from a cascade membrane separation process

Skimmed milk was fractionated via a cascade system: Graphic plotting of microfiltration (MF); ultrafiltration (UF); nanofiltration (NF); and reverse osmosis (RO). The buffering curves of each fraction were studied over the pH range 4–7. Depending on their composition, the individual permeate streams showed different buffering capacity values and pH ranges where the buffering occurred. The concentration of active buffering substances in the permeates decreased (in mmol/L) from ~26.6 (MF) to ~17.4 (UF) to 1.39 (NF) to 0.07 (RO). Contributions to the total buffering capacity for MF permeate, which represents the serum phase of milk, were ~37% from whey proteins and ~63% from milk salts (especially citrates, phosphates and carbonates) including lactose and water.     

超滤膜分离技术回收乳清蛋白工艺研究

研究利用超滤膜分离技术,从干酪素乳清废弃液中回收乳清蛋白,通过对不同超滤膜性能的比较,选择最佳的超滤膜材料、工艺流程以及运行参数,并测得分离效果。结果表明:采用PW2540型聚醚砜卷式超滤膜较好,其最佳工艺参数为操作温度35℃,操作压力0.5MPa,且超滤膜透液通量较高,运行稳定。乳清蛋白粉中蛋白质含量72.40%,灰分3.85%。经红外光谱检测证明乳清蛋白粉品质得到较大程度的提高。每吨乳清废弃液中可回收乳清蛋白粉5.13kg,具有较好的经济效益及减排环保效益。     

新会柑脱苦工艺研究

以新会柑为实验原料,采用活性炭对柑汁进行脱苦研究.通过正交实验得出,1.5%的活性炭,果汁温度为10℃,活性炭作用时间为60min时,能脱除28.80%的柚皮苷和42.63%的柠檬苦素.     

一种新型乳清碳酸饮料的制作工艺

介绍了一种将脱盐乳清粉配制成10%的水溶液,用β-半乳糖苷酶酶解降低其乳糖含量,经两组串联超滤装置处理得到澄清的饮料原液,最后调配加工成澄清型低乳糖碳酸饮料的制作工艺。结果表明,用以上处理方法可制得具有奶香风味、口感清爽并可供长期保存的乳清碳酸饮料。     

大豆乳清废水膜过程生产低聚糖工艺研究

主要探讨了乳清废水膜过程生产低聚糖等产品工艺中各级膜滤过程和其他流程试验,采用正交试验确定了低聚糖液的活性炭最佳脱色条件:脱色时间30 min,加炭量2.0%,脱色温度70℃,pH4.0,同时还对脱色后的低聚糖液的树脂脱盐试验进行了研究.乳清废水经过该工艺过程,最终形成了大豆低聚糖产品,超过了主产品的效益,水质接近纯净水并回用至工序中.     

MVR技术在大豆乳清废水处理中的应用研究

研究了MVR技术在大豆乳清废水处理中的应用。通过单因素试验及对大豆乳清废水的分析,基于保证乳清蛋白活性的目的得到MVR处理大豆乳清废水最佳工艺条件为:压缩机频率100 Hz,加热温度65℃。在最佳条件下回收1 t大豆乳清废水用电13 k W·h。     

Direct measurement of the force required to disrupt and remove fouling deposits of whey protein concentrate

A micromanipulation technique has been used to measure directly the adhesive strength of whey protein deposits on a stainless-steel surface. The principle of this technique is to use a T-shaped probe to pull fouling deposits away from the surface to which they are attached, and to measure the force imposed on the probe simultaneously. The apparent adhesive strength between the fouling deposits and the substrate was measured as the work required to remove the deposits per unit area from the surface. Measured values of the apparent cohesive/adhesive strength were between 0 and 10 J m⁻², which was a function of temperature, cleaning agent concentration and exposure time. The adhesive strength of whey protein deposits was greater than the cohesive strength at room temperature. The results can be compared with larger-scale cleaning processes, and potentially used to design new cleaning processes and operating protocols.     

以酶法改性乳清蛋白为基质的脂肪替代品在冰淇淋中的应用

以酶法水解的乳清蛋白WPC-80为基质制备脂肪替代品,替代中脂冰淇淋中25%的脂肪。随着乳清蛋白水解度的增加,冰淇淋浆料粘度和膨胀率略有下降,抗融化率提高,制得低脂冰淇淋的各项感官指标均优于对照组。当乳清蛋白的水解度为4%时,制得的脂肪替代品添加到冰淇淋中,各项感官指标最佳。     

膜技术在L-丙氨酸提纯工艺中的应用研究

采用陶瓷膜和纳滤膜工艺从发酵液中提取L-丙氨酸。经试验研究,确定了陶瓷膜过滤的料液经过80 ℃高温灭菌20 min,膜面流速控制在5 m/s;并对纳滤膜进行选型,最终确定UA60纳滤膜对料液进行脱色、脱盐,透光率提高43.6%,磷酸盐去除率为59.8%,对丙氨酸的截留率为10.5%。使用膜过滤提纯后,L-丙氨酸的总收率为85.9%。     

乳清酒饮料发酵工艺的研究

研究了乳清酒饮料的发酵工艺,结果表明,酒精发酵最佳条件为接种量4%,初始pH7.9,温度20℃,时间50h。乳清多肽酒精饮料的配方为β-环状糊精量0.3%,酸量0.15%,复合甜味剂量9%。     

Filtration of milk fat globule membrane fragments from acid buttermilk cheese whey

The proteins and polar lipids present in milk fat globule membrane (MFGM) fragments are gaining attention for their technological and nutritional properties. These MFGM fragments are preferentially enriched in side streams of the dairy industry, like butter serum, buttermilk, and whey. The objective of this study was to recover MFGM fragments from whey by tangential filtration techniques. Acid buttermilk cheese whey was chosen as a source for purification by tangential membrane filtration because it is relatively rich in MFGM-fragments and because casein micelles are absent. Polyethersulfone and cellulose acetate membranes of different pore sizes were evaluated on polar lipid and MFGM-protein retention upon filtration at 40°C. All fractions were analyzed for dry matter, ash, lipids, proteins, reducing sugars, polar lipid content by HPLC, and for the presence of MFGM proteins by sodium dodecyl sulfate-PAGE. A fouling coefficient was calculated. It was found that a thermocalcic aggregation whey pretreatment was very effective in the clarification of the whey, but resulted in low permeate fluxes and high retention of ash and whey proteins. By means of an experimental design, the influence of pH and temperature on the fouling and the retention of polar lipids (and thus MFGM fragments), proteins, and total lipids upon microfiltration with 0.15 μM cellulose acetate membrane was investigated. All models were highly significant, and no outliers were observed. By increasing the pH from 4.6 to 7.5, polar lipid retention at 50°C increased from 64 to 98%, whereas fouling of the filtration membrane was minimized. A 3-step diafiltration of acid whey under these conditions resulted in a polar lipid concentration of 6.79 g/100 g of dry matter. As such, this study shows that tangential filtration techniques are suited for the purification of MFGM fragments.