大豆乳清蛋白特性及回收利用研究进展

大豆分离蛋白加工过程中产生大量乳清废水,直接排放会造成环境污染和资源浪费。大豆乳清废水中含有大豆乳清蛋白(Soybean Whey Proteins, SWP)、大豆异黄酮、大豆低聚糖等多种营养成分,其中大豆乳清蛋白应用价值极高,富含胰蛋白酶抑制剂、β-淀粉酶、大豆血球凝集素、脂肪氧合酶等多种功能因子。基于此,本文针对大豆乳清蛋白的回收利用,归纳总结了大豆乳清蛋白中的主要组成成分,并对各组分的研究利用以及其功能特性进行总结与分析,同时对大豆乳清蛋白的回收方法及利用进行了梳理,以期为工业生产实践中高值化利用提供理论和技术上的参考。     

大豆乳清废水的回收利用研究进展

大豆乳清废水（SWW）是豆腐和大豆分离蛋白生产过程产生的废水。该废水排放量大,且富含大豆乳清蛋白、低聚糖和大豆异黄酮等有机物。目前,大部分企业将该废水排放至污水处理厂进行生化处理,不仅造成豆腐和大豆分离蛋白生产成本的增加,还导致大量有机物的流失。因此,资源化大豆乳清废水成为企业亟待解决的难题。鉴于此,本文从回收大豆乳清废水中的活性成分和生物转化大豆乳清废水两个角度,综述了近年来大豆乳清废水资源化的相关研究报道,并指出了两种策略的优缺点。研究发现,大部分大豆乳清废水资源化方法尚处于实验阶段,仅在废水中大豆乳清蛋白的回收并用于动物饲料与生物转化为沼气两个方面实现了工业化生产。针对上述现状,提出在未来应从以下三个方面进行研究以促进大豆乳清废水资源化的大规模资源化:降低大豆乳清废水中活性成分的分离成本并提高其利用价值;提高大豆乳清废水生物转化效率、转化率和产品附加值;对资源化方法进行经济效益核算,评估其工业化的可能性。     

大豆乳清废水综合利用研究进展

大豆乳清废水是大豆分离蛋白生产过程中产生的有机废水,也是该工艺过程中产生的最大量的废弃物。研究表明,大豆乳清废水中的多种有机组分具有一定的生物活性和医疗保健功能,具有较高的回收利用价值。介绍了大豆乳清废水的主要组分及含量,并对各组分的功能作用和各组分的分离提取进行了总结与分析,对大豆乳清废水用于新型功能性饮料的开发现状进行总结,并对大豆乳清废水的综合利用进行了展望,为大豆乳清废水的综合利用提供理论和实践的指导。     

炼油废水污染控制处理工艺的探究与革新

油污染是水体污染的重要类型之一,特别是河口、近海水域更为突出,油污染会破坏滨海风景,危害水生生物。炼油废水是造成油污染的主要来源,本文通过研究炼油废水的特征和危害,重点介绍了炼油废水的污染控制化学原理和方法以及处理中存在的问题,并简单介绍了炼油废水的废水回收与利用。     

印染退浆废水PVA处理技术

聚乙烯醇(PVA)是经纱上浆的主要浆料,生物化学稳定性好.含PVA的印染退浆废水具有COD浓度高、可生化性差等特点,处理难度大.通过调研国内外PVA废水处理技术及回收利用实践状况,讨论了生物降解、超滤、化学凝结法等技术处理印染废水PVA的特点和适用范围,并以某纺织印染企业PVA回收处理工程为例简要介绍化学凝结法,认为化学凝结法是现阶段PVA印染废水回收处理较为适用的工艺之一.     

乳清的成分及其利用

乳清是从牛乳中除去脂肪、酪蛋白、脂溶性维生素等剩下的水溶性部分。乳清为透明带萤光的黄绿色溶液。其主要成分是乳糖。过去乳清作为制造干酪和干酪素的付产品,仅有极少的一部分被利用,大量的乳清被弃之不用。对于大量制造干酪的欧美各国,在经济上也是一个重要问题。但因为乳清的干物质的含量少,仅6％左右,而干物质中乳糖占70％。无机     

皮革印染废水资源化利用技术及其经济效益分析

本文针对皮革印染废水资源化利用技术及其经济效益进行了综合分析。首先介绍了传统废水处理方法存在的局限性和不足之处,然后详细阐述了物理处理、化学处理和生物处理等资源化利用技术的原理和应用案例。接着,对皮革印染废水资源化利用技术的经济效益进行了全面评估,包括成本分析和收益分析。研究结果表明,这些技术在降低企业污染排放、回收有价值资源等方面具有显著的经济效益。     

乳白蛋白及其用途

目前绝大部分乳白蛋白作为高营养价值的乳清蛋白随同乳清一起排掉,这对食品和乳品工业都是个损失。最近由于加工技术的进展,从乳精中回收白蛋白的方法得到改进,可以收回变性和未变性的乳白蛋白。文章指出,食品和乳品工业未来能够利用乳白蛋白和制造乳白蛋白产品。文章介绍了如下方法:①乳清离心加工法,乳品工业已开始利用乳清离心加工法来回收乳清蛋白,在离心乳清加工中,通过酸化和热处理结合的方法,使蛋白质从无脂乳清中沉淀出来。蛋白质通过离心分离得到稠厚的浆液,把它加到干酪乳内,使干酪产量增加。此     

聚丙烯微孔膜固定化转谷氨酰胺酶在大豆乳清废水处理中的应用

将固定化转谷氨酰胺酶酶膜应用到酶膜反应器中,对大豆乳清废水进行催化使其发生聚合并被截留,从而减轻大豆乳清废水对环境的污染,并确定其最佳影响条件,得出在最佳条件下进行处理的蛋白截留率为78.4%。对处理前后大豆乳清废水进行分析,其主要成分指标发生了很大变化,如蛋白质含量、生化需氧量(biochemical oxygen demand,BOD)值、化学需氧量(chemical oxygen demand,COD)值、灰分含量等指标较处理前发生显著下降。     

乳清蛋白改性研究进展

乳清蛋白是动物乳中的一种优质蛋白质,具有丰富的营养价值和独特的生理功能。天然乳清蛋白性质极不稳定,为使乳清蛋白得到高效利用,衍生出许多各具特色的改性方法。本文综述了利用物理方法、生物方法、化学方法及新技术改性乳清蛋白的研究进展。物理方法主要包括热处理、高压处理、微波辐照处理、超声处理、超临界二氧化碳流体处理和低温等离子体处理等;生物方法主要包括酶法水解和酶法交联处理两种;化学方法包括磷酸化、糖基化、酰化、去酰胺、酸调处理等。此外,本文总结了不同改性方法的作用机制及其对乳清蛋白性质的影响,同时展望了乳清蛋白改性技术的应用及发展趋势。     

Colorants in cheese manufacture: Production,chemistry, interactions,and regulation

Colored Cheddar cheeses are prepared by adding an aqueous annatto extract (norbixin) to cheese milk; however, a considerable proportion (～20%) of such colorant is transferred to whey, which can limit the end use applications of whey products. Different geographical regions have adopted various strategies for handling whey derived from colored cheeses production. For example, in the United States, whey products are treated with oxidizing agents such as hydrogen peroxide and benzoyl peroxide to obtain white and colorless spray‐dried products; however, chemical bleaching of whey is prohibited in Europe and China. Fundamental studies have focused on understanding the interactions between colorants molecules and various components of cheese. In addition, the selective delivery of colorants to the cheese curd through approaches such as encapsulated norbixin and microcapsules of bixin or use of alternative colorants, including fat‐soluble/emulsified versions of annatto or beta‐carotene, has been studied. This review provides a critical analysis of pertinent scientific and patent literature pertaining to colorant delivery in cheese and various types of colorant products on the market for cheese manufacture, and also considers interactions between colorant molecules and cheese components; various strategies for elimination of color transfer to whey during cheese manufacture are also discussed.     

Current trends in whey processing and utilization in Greece

Whey treatment began in Greece in 1998; in previous years, whey was considered only as effluent from cheese production, a part of which yielded whey cheeses. In 1998, the first whey powder plant started to operate successfully. The main physicochemical characteristics of whey from feta cheese production are illustrated, together with those of the 'cooked' whey, ie the serum remaining after whey cheese production. Quality standards for both types of whey are proposed. The drive for efficient whey processing is the unrelenting demand for whey products in the local market and the current status is described.     

Variation of Total and Available Lysine in Dehydrated Products from Cheese Wheys by Different Processes

Excessive or prolonged exposure to heat during manufacture of dehydrated products from cheese whey and cheese whey protein concentrates is chiefly responsible for decreasing the lysine content of these products. With ion exchange chromatography of acid hydrolysates to determine total lysine, and 2,4,6,-trinitrobenzene sulfonic acid reagent to determine available lysine with its epsilon amino group free for chemical reaction, both total and available lysine were higher in spray-dried whey powders than in roller-dried whey powders. Of the lysine originally available in the protein of cottage cheese whey, 88% remained available in an experimental dehydrated high-protein isolate prepared by ultrafiltration, followed by gel permeation followed by pasteurization, vacuum evaporation, and shelf drying of the protein concentrate. Unfractionated foam spray-dried cottage cheese whey powder retained 96% of the original available lysine.     

Pre-treatment methods of Edam cheese milk. Effect on the whey composition

Edam cheese milk was subjected to high-heat treatment (HH), ultrafiltration (UF) and microfiltration (MF). The effect on the recovery yield and the composition of whey was studied. Traditional Edam process was used as a reference. HH reduced the whey protein concentration of milk and whey, but the recovery from milk to whey was not affected. Reduction of whey proteins was the highest (28%) with MF treatment, during which 15% was lost in the MF permeate and 13% was co-precipitated with the cheese curd. Co-precipitation of the whey proteins was the highest (84%) with ultrafiltered milk. MF and UF treatments produced 22% less whey with increased whey protein concentration. Elevation of the cheese milk protein concentration by microfiltration or ultrafiltration decreased the recovery of fat in whey. None of the treatments decreased the residual casein concentration in whey. The protein composition was altered by UF and MF treatments, which significantly increased the caseinomacropeptide content of total protein in whey. The whey was processed into whey protein concentrate powders. The amino acid composition of the whey protein concentrate produced from microfiltration process was significantly different from the others.     

Use of acid whey protein concentrate as an ingredient in nonfat cup set-style yogurt

Acid whey resulting from the production of soft cheeses is a disposal problem for the dairy industry. Few uses have been found for acid whey because of its high ash content, low pH, and high organic acid content. The objective of this study was to explore the potential of recovery of whey protein from cottage cheese acid whey for use in yogurt. Cottage cheese acid whey and Cheddar cheese whey were produced from standard cottage cheese and Cheddar cheese-making procedures, respectively. The whey was separated and pasteurized by high temperature, short time pasteurization and stored at 4°C. Food-grade ammonium hydroxide was used to neutralize the acid whey to a pH of 6.4. The whey was heated to 50°C and concentrated using ultrafiltration and diafiltration with 11 polyethersulfone cartridge membrane filters (10,000-kDa cutoff) to 25% total solids and 80% protein. Skim milk was concentrated to 6% total protein. Nonfat, unflavored set-style yogurts (6.0 ± 0.1% protein, 15 ± 1.0% solids) were made from skim milk with added acid whey protein concentrate, skim milk with added sweet whey protein concentrate, or skim milk concentrate. Yogurt mixes were standardized to lactose and fat of 6.50% and 0.10%, respectively. Yogurt was fermented at 43°C to pH 4.6 and stored at 4°C. The experiment was replicated in triplicate. Titratable acidity, pH, whey separation, color, and gel strength were measured weekly in yogurts through 8 wk. Trained panel profiling was conducted on 0, 14, 28, and 56 d. Fat-free yogurts produced with added neutralized fresh liquid acid whey protein concentrate had flavor attributes similar those with added fresh liquid sweet whey protein but had lower gel strength attributes, which translated to differences in trained panel texture attributes and lower consumer liking scores for fat-free yogurt made with added acid whey protein ingredient. Difference in pH was the main contributor to texture differences, as higher pH in acid whey protein yogurts changed gel structure formation and water-holding capacity of the yogurt gel. In a second part of the study, the yogurt mix was reformulated to address texture differences. The reformulated yogurt mix at 2% milkfat and using a lower level of sweet and acid whey ingredient performed at parity with control yogurts in consumer sensory trials. Fresh liquid acid whey protein concentrates from cottage cheese manufacture can be used as a liquid protein ingredient source for manufacture of yogurt in the same factory.     

Cottage cheese whey as an ingredient of cottage cheese dressing mixes

The objective of this study was to formulate and develop a good quality cottage cheese dressing using acid whey as the main ingredient. Up to 72% of cottage cheese whey was used in the dressing mixes. The percentage of fat (4.10–5.05%) and total solids (19.41–20.24%) approached the desired level and was within the legal limits for regular cottage cheese. Sensory evaluation scores for flavour, body/texture and appearance were not adversely affected by the use of acid whey. The sensory evaluation scores for all four products made with whey- or skimmed milk-based dressings were higher than the commercial control.     

Proteolysis on Reggianito Argentino cheeses manufactured with natural whey cultures and selected strains of Lactobacillus helveticus

Reggianito Argentino cheese is traditionally manufactured with whey starter cultures that provide typical and intense flavor but can cause poor quality standardization. In this study, the influence of natural and selected starters on Reggianito Argentino cheese proteolysis was investigated. Cheeses were manufactured with three strains of Lactobacillus helveticus (SF133, SF138 and SF209) cultured individually in sterile whey and used as single or mixed starters. Control cheeses were made with natural whey starter culture. Cheeses were analyzed to determine gross composition, as well as total thermophilic lactic flora. Proteolysis was assessed by N fractions, electrophoresis and liquid chromatography. Gross composition of the cheeses did not significantly differ, while viable starter cell counts were lower for cheeses made with strain SF209 alone or combined with other strains. Soluble N at pH 4.6 was the same for cheeses made with natural or selected starters, but soluble N in 12% trichloroacetic acid and 2.5% phosphotungstic acid was significantly higher in cheeses made with starters containing strain SF209. Nitrogen fractions results indicated that natural whey starter cultures could be replaced by several starters composed of the selected strains without significant changes to proteolysis patterns. Starter cultures prepared only with SF209 or with the three selected L. helveticus strains produced cheese products with significantly more proteolysis than control cheeses. Chromatographic profiles analyzed by principal components showed that three main peaks on chromatograms, presumptively identified as Tyr, Phe, and Trp, explained most of variability. Principal component scores indicated that cheese samples were grouped by ripening time, which was confirmed by linear discriminant analysis. On the contrary, samples did not cluster by Lactobacillus strain or type of starter.     

Size classification of precipitated calcium phosphate using hydrocyclone technology for the recovery of minerals from deproteinised acid whey

Acid whey is generated during the manufacture of acidified dairy products, such as soft cheeses, acid casein ingredients and strained yoghurts. Examples of these whey‐based by‐products include Cottage cheese acid whey and Greek yoghurt acid whey. Alkalisation of acid whey at elevated temperatures (60 °C) precipitates calcium phosphate, which can be recovered and used as an ingredient. The novel application of a liquid–solid hydrocyclone in the size classification of calcium phosphate from heated and neutralised acid whey was investigated in this study. Factors influencing hydrocyclone performance were tested, and the technology was integrated into a membrane filtration‐based process for the production of milk mineral powders.     

Transglutaminase-mediated incorporation of whey protein as fat replacer into the formulation of reduced-fat Iranian white cheese: physicochemical,rheological and microstructural characterization

The effects of transglutaminase treatment (0–2 units/g milk protein) on the chemical composition, textural characteristics, proteolysis and yield of reduced-fat Iranian white cheese (milk fat: 0.4–1.4% w/w) incorporated with whey proteins (0–6 g/L milk) were investigated. Enzyme-mediated inclusion of whey proteins in the reduced-fat cheese caused a noticeable increase in moisture to protein (M:P) ratio with concomitant decease in the hardness rheological parameters of fracture stress and Young’s and storage (G’) moduli. However, increase in concentrations of whey proteins or/and transglutaminase enzyme above a critical level led to formation of a cheese matrix with lower moisture content and greater values of hardness indices. Whey protein addition and transglutaminase treatment resulted in the same trends of changes in proteolysis rate and cheese yield as in cheese softness. Response surface method (RSM) suggested that the enzymatic incorporation of 4.2 g deliberately added whey proteins to 1 L of milk (1.04% w/w fat) into the cheese matrix using 0.833 unit transglutaminase per gram milk protein would provide a reduced-fat product with the softest texture and the highest yield. The scanning electron micrographs showed formation of honeycomb structures in the protein matrix of the reduced-fat sample with optimum formulation.