The formation of calcium lactate crystals is responsible for concentrated acid whey thickening

The use of spray drying for dehydration of acid whey is generally limited by the appearance of uncontrolled thickening and solidifying of the whey mass during the lactose crystallization step. The origin of this physical change is still unknown and probably linked to complex interactions between physical properties and chemical composition of these products. To understand this phenomenon, we simulated the thickening of concentrated acid whey on a laboratory scale by measuring the flow resistance changes as a function of time and whey composition. The thickening process was characterized by an amplitude of torque and a lag time (induction time). Thickening of lactic acid whey concentrate occurred regardless of the presence of whey proteins or lactose crystals. Moreover, this work clearly demonstrated that the thickening process was due to the formation of filamentous structures corresponding to calcium lactate crystals and showed a large dependence on calcium and lactate contents, pH, and phosphate concentration.     

Spray-dried whey protein/lactose/soybean oil emulsions. 2. Redispersability, wettability and particle structure

In the present paper redispersion and wettability experiments of spray-dried whey protein-stabilized emulsions are presented. Emulsion droplet size after redispersion gives information about eventual coalescence between emulsion droplets in the powder matrix during drying or storage, resulting in an increase in emulsion droplet size after redispersion. Results from redispersion experiments are combined with previously presented knowledge about powder surface composition and particle structure to elucidate internal processes in the powder matrix and external processes on the powder surface during drying and storage of whey protein powder. The results show that with addition of lactose to whey protein-stabilized emulsions, emulsion droplet structure remains intact in the powder matrix during drying since the emulsion droplet size in the redispersed spray dried emulsion is unchanged. In the absence of lactose there is a growth in emulsion droplet size after redispersion of the spray-dried whey protein-stabilized emulsion, showing that a coalescense of emulsion droplets occurs during the drying or redispersion process. Storage of the whey protein-stabilized powders in a humid atmosphere (relative humidity 75%, 4 days) induces changes in some powders. When the powder contains a critical amount of lactose there is a remarkable increase in emulsion droplet size after redispersion of humid stored powders compared with the emulsion before drying and with the redispersed dry stored powder. In addition, there is a release of encapsulated fat after humid storage of lactose-containing powders detected by electron spectroscopy for chemical analysis. For powders which do not contain any lactose there is no increase in emulsion droplet size after storage in a humid atmosphere compared with the redispersed dry stored emulsion. Addition of only a small amount of lactose prevents coalescence of emulsion droplets and the subsequent increase in droplet size during drying. If the lactose content is kept rather low neither an effect on the droplet size after storage under humid conditions nor a release of fat onto powder surfaces is detected. Furthermore, wettability of the spray-dried whey protein-stabilized emulsions by water is presented. It is concluded that it is beneficial to wettability in water to have as high a coverage of lactose on the powder surface as possible. In addition, a review of particle structure for powders of various composition is presented.     

Dairy powder rehydration: influence of protein state, incorporation mode, and agglomeration

A simplified method to study rehydration was used on different dairy powders. The method involved dispersing powder in a stirred vessel equipped with a turbidity sensor. The changes of turbidity occurring during powder rehydration highlighted the rehydration stage, and the influence of the proteins’ state on rehydration was clarified. Casein powders had a quick wetting time but very slow dispersion, making the total rehydration process time-consuming. On the other hand, whey powders were found to have poor wettability but demonstrated immediate dispersion after wetting. Mixing casein (80%) and whey (20%) before spray drying greatly improved rehydration time compared with casein powder; whereas mixing whey powder with casein powder at the same ratio after spray drying caused a dramatic deterioration in the rehydration properties. Moreover, agglomeration was found to significantly improve the rehydration time of whey protein powder and to slow down the rehydration time of casein powder. These opposite effects were related to the rate-controlling stage (i.e., wetting stage for whey protein and dispersion stage for casein).     

Stability of microencapsulated lactic acid bacteria under acidic and bile juice conditions

The probiotic strains Lactobacillus brevis CCMA1284 and Lactobacillus plantarum CCMA0359 were microencapsulated by spray drying using different matrices – whey powder (W), whey powder with inulin (WI) and whey powder with maltodextrin (WM). Viability of the microencapsulated strains in acid and bile juices and during 90 days of storage (seven and 25 °C) was evaluated. The two strains exhibited high encapsulation efficiency (> 86%) by spray drying. The different matrices maintained L. plantarum viability above six log CFU g⁻¹ at 7 °C for 90 days, whereas similar results for L. brevis were observed only for W. The use of inulin as matrix of encapsulation did not enhance bacterial viability in the evaluated conditions. In general, the use of W and WM as matrices was effective for L. plantarum viability. However, only W was effective for L. brevis in the evaluated conditions. The spray drying technique was successfully adopted for the encapsulation of L. plantarum CCMA0359 and L. brevis CCMA1284 strains.     

Influence of Wall Material and Inlet Drying Air Temperature on the Microencapsulation of Fish Oil by Spray Drying

Several single and composite milk-originated wall materials were used to microencapsulate fish oil via spray drying at various inlet drying air temperatures. Skim milk powder (SMP), whey protein concentrate, whey protein isolate (WPI), 80% WPI?+?20% milk protein concentrate, and 80% WPI?+?20% sodium caseinate (NaCas) were applied as the wall for capsules generated at drying air temperatures of 140, 160, and 180 °C. The higher the drying air temperature, the higher was the particle size, encapsulation efficiency, and peroxide value and the lower was the moisture content and bulk density. The microcapsules prepared with SMP showed the highest encapsulation efficiency and lowest peroxide value for the oil due to the presence of lactose in its chemical composition. Differential scanning calorimetry and Fourier transform infrared analyses indicated the absence of any significant interaction between SMP and fish oil.     

Chemical composition and nutritive value of spray dried permeate powder

Reconstituted skimmed milk (10% TS) was ultrafiltered, and the permeate was concentrated threefold by reverse osmosis and then spray dried at different temperatures (145–195° C). The drying conditions had no effect on the moisture content or the major constituents of permeate powder. The powder was mainly lactose (85%) with 6.35460% ash. A small percentage of the lactose in the permeate powder was present as a-lactose. Sodium, potassium and citrate were present in high concentrations nearly equivalent to their average percentage in skimmed milk. The calcium, magnesium and inorganic phosphorus contents of permeate powder were also determined. The thiamine, riboflavin and niacin contents of permeate powder averaged 0.445, 0.947 and 0.729 mg/100 g respectively. The drying temperatures had no effect on the vitamin contents of the powder. The permeate powder had average Fe, Zn, Mn and Cu contents of 94.7, 21.1, 3.1 and 9.5 Fg/100 g respectively.     

基于陶瓷膜技术的羊乳酪蛋白和其他组分的高效分级分离

为量化0.05 μm陶瓷膜脱除羊乳中乳清蛋白、乳糖、灰分、钙和磷的能力,在50 ℃条件下,脱脂乳进行3 倍浓缩,之后2 次间歇补水至原体积进行清洗过滤,最终得到1 份截留液、3 份透过液,并计算各组分总脱除率。结果表明：乳清蛋白脱除率为96.17%,乳糖脱除率为86.42%,灰分脱除率为73.39%,钙脱除率为34.90%,磷脱除率为55%。稀释过滤完毕后膜的纯水膜通量衰减系数为55.57%,使用质量分数为2%氢氧化钠和1%的硝酸溶液进行清洗,膜通量的恢复系数为99.21%。0.05 μm陶瓷膜可以实现羊乳酪蛋白和其他组分的有效分离,该技术适合在没有干酪乳清的条件下,以生鲜乳为原料加工酪蛋白胶束粉、乳清蛋白粉、乳糖等乳基配料产品。     

Characteristics of soy sauce powders spray-dried using dairy whey proteins and maltodextrins as drying aids

This study investigated the effect of adding whey protein isolate (WPI) as a complementary drying aid of maltodextrin (MD) on spray drying of soy sauce powders. Soy sauce powders were prepared by spray drying soy sauce liquid adding 5%, 10% and 15% of WPI respectively together with MD as the drying aids. Tests were conducted to evaluate the powder properties relevant to the caking issue of the soy sauce powders. Results showed that addition of just 5% WPI could significantly increase the product yield for the spray drying process. At the same time, the caking strength of the spray dried soy sauce powders were significantly reduced during storage with WPI addition. XPS results indicated that WPI have preferential migration to the surface of the soy sauce powder. The over-expression of WPI on powder surface after spray drying might explain the improved stability for soy sauce powders during the caking test.     

Spray-dried whey protein/lactose/soybean oil emulsions. 1. Surface composition and particle structure

Emulsions made of whey protein, lactose and soybean oil were spray-dried and the chemical surface composition of the dried powders estimated by electron spectroscopy for chemical analysis. In particular, the ability of whey protein to encapsulate fat was highlighted. Additionally, the structure of the spray-dried powder particles was studied by scanning electron microscopy. The powders were examined after storage in both dry and humid atmospheres (relative humidity 75%, 4 days). It was found that the ability of whey protein to encapsulate soybean oil is rather low compared with sodium caseinate, with a large part of the powder surface covered by fat after spray-drying. After storage in humid atmosphere there is a release of encapsulated oil onto the powder surface in most cases, and an increase in fat coverage. The release offat onto the powder surfaces causes the particle structure to change dramatically for powders containing a critical amount of lactose. Such powders agglomerate and lose structure completely. In comparison, powders containing no lactose storage under humid conditions also cause a release of fat onto the powder; however, in this case particle structure remains intact. Powders containing only a small amount of lactose, up to ~25% of emulsion dry weight, do not exhibit the release of fat onto the powder surfaces after storage under humid conditions and the structure of these powder particles does not change. The presence of lactose in whey protein-stabilized emulsions, however, does not increase fat encapsulation by whey protein, as reported earlier for sodium caseinate-stabilized emulsions that were spray-dried. During spray-drying of whey protein/lactose solutions there is a strong overrepresentation of surface-active whey protein on the powder surface. Whey protein coverage increases even further when the powders are stored under humid conditions, also making them lose structure.     

Effects of lactic acid concentration and spray drying conditions on stickiness of acidified skim milk powder

The effects of lactic acid concentration (LA) and spray drying conditions on stickiness of acidified skim milk powder (SMP), which impacts process efficiency and powder properties, were examined using a fully replicated 2^4-1 fractional factorial design. The wall deposition was significantly affected by LA, and yield was positively influenced by the drying temperature difference. Drying temperature difference significantly affected particle size, moisture content and water activity of acidified SMP. Particle size was also significantly influenced by nozzle airflow rate. Moisture content and water activity were significantly affected by LA, while glass transition temperature was only influenced by the outlet temperature.     

Drying of Whey

The properties of lactose in whey powder and the effect of crystallization are assessed and the process of mutarotation described. Concentration in an evaporator and the influence of heat­treatment in the process of whey is considered and the action of proteins on viscosity shown. Thermoplasticity in the drying of whey concentrate and the possibility of producing a high-quality non­caking powder are discussed. Editor's summary     

喷雾干燥法制备冰酒发酵剂的研究

从四川藏区高原霞多丽冰葡萄渣中分离纯化出了一种菌株,经18S rDNA D1/D2序列鉴定为葡萄汁有孢汉逊酵母（Hanseniaspora uvarum）,并通过正交试验对保护剂的配方进行优化,单因素试验初步研究喷雾干燥的的条件。结果表明,喷雾干燥最佳保护剂的配方为脱脂奶粉7%,酵母浸粉5%,乳糖0.6%,黄原胶0.20%,得到的干菌粉中的活菌数为2.6×1010 CFU/g;确定喷雾干燥实验最适条件为进口温度120 ℃,进样流量20 mL/h,保护剂与菌泥比例4∶1（g∶L）,按上述条件得到的干菌粉的活菌数为2.4×108 CFU/g。     

Ration digestibility and mineral balance in lactating cows fed rations containing dried whey.

Including dried whey in rations of nonruminants usually increases digestibilities and mineral retention, presumably because of the lactose in the whey. A trial with total collection had five lactating cows per treatment to determine the effects of 5% dried whey product in the concentrate on digestibility of the ration and on absorption and retention of calcium, magnesium, and phosphorus. Rations included corn silage ad libitum, 3 kg alfalfa hay, and either control or dried whey product in concentrate ration at 1 kg/3 kg milk produced. Rations were balanced for content of nitrogen, calcium, magnesium, and phosphorus. Digestibilities of dry matter, nitrogen, and energy were not increased with dried whey product in the ration. Apparent absorption of calcium, magnesium, and phosphorus was not affected significantly by inclusion of whey in the ration. Productive (milk plus retained) calcium and magnesium were not increased when dried whey product was in the ration although productive phosphorus was slightly higher with the dried whey product. Adding small amounts of dried whey to a ruminant's ration will not increase mineral absorption and retention probably because tthe lactose in dried whey is fermented in the rumen and unavailabe for aiding absorption from the small intestine.     

Water sorption and glass transition properties of spray dried lactose hydrolysed skim milk powder

The moisture sorption behaviour and glass transition temperature of spray dried skim milk powder with hydrolysed lactose (SMPHL) were determined. Spray drying of skim milk with hydrolysed lactose resulted in very low cyclone recovery of 25% and a large amount of powder remained stuck inside the spray dryer. The equilibrium moisture content of SMPHL was lower than that of lactose for each range of water activity when humidified for 21 days at 23 °C using saturated salt solutions. Unlike lactose, SMPHL did not lose water when the water activity exceeded 0.432 and no crystallization was noticed at water activity ?0.753. The sorption isotherm data for SMPHL fitted well with the BET and GAB models with monolayer moisture contents of 7.55 and 8.27 g/100 g, respectively. The glass transition temperature of anhydrous SMPHL was 49 °C. The critical water activity and moisture content for SMPHL were 0.15 and 2.4 g/100 g dry solid, respectively. The low critical values indicated hydrolysis of lactose necessities maintenance of very low moisture of powder for its long-term stability.     

The effect of acidification of liquid whey protein concentrate on the flavor of spray-dried powder

Off-flavors in whey protein negatively influence consumer acceptance of whey protein ingredient applications. Clear acidic beverages are a common application of whey protein, and recent studies have demonstrated that beverage processing steps, including acidification, enhance off-flavor production from whey protein. The objective of this study was to determine the effect of preacidification of liquid ultrafiltered whey protein concentrate (WPC) before spray drying on flavor of dried WPC. Two experiments were performed to achieve the objective. In both experiments, Cheddar cheese whey was manufactured, fat-separated, pasteurized, bleached (250 mg/kg of hydrogen peroxide), and ultrafiltered (UF) to obtain liquid WPC that was 13% solids (wt/wt) and 80% protein on a solids basis. In experiment 1, the liquid retentate was then acidified using a blend of phosphoric and citric acids to the following pH values: no acidification (control; pH 6.5), pH 5.5, or pH 3.5. The UF permeate was used to normalize the protein concentration of each treatment. The retentates were then spray dried. In experiment 2, 150 μg/kg of deuterated hexanal (D₁₂-hexanal) was added to each treatment, followed by acidification and spray drying. Both experiments were replicated 3 times. Flavor properties of the spray-dried WPC were evaluated by sensory and instrumental analyses in experiment 1 and by instrumental analysis in experiment 2. Preacidification to pH 3.5 resulted in decreased cardboard flavor and aroma intensities and an increase in soapy flavor, with decreased concentrations of hexanal, heptanal, nonanal, decanal, dimethyl disulfide, and dimethyl trisulfide compared with spray drying at pH 6.5 or 5.5. Adjustment to pH 5.5 before spray drying increased cabbage flavor and increased concentrations of nonanal at evaluation pH values of 3.5 and 5.5 and dimethyl trisulfide at all evaluation pH values. In general, the flavor effects of preacidification were consistent regardless of the pH to which the solutions were adjusted after spray drying. Preacidification to pH 3.5 increased recovery of D₁₂-hexanal in liquid WPC and decreased recovery of D₁₂-hexanal in the resulting powder when evaluated at pH 6.5 or 5.5. These results demonstrate that acidification of liquid WPC80 to pH 3.5 before spray drying decreases off-flavors in spray-dried WPC and suggest that the mechanism for off-flavor reduction is the decreased protein interactions with volatile compounds at low pH in liquid WPC or the increased interactions between protein and volatile compounds in the resulting powder.     

Ernährungsphysiologische Bedeutung von Molke und Molkenbestandteilen

Nutritional significance of whey and whey components Deriving from positive effects of whey drinking cures in antiquity, the Middle Ages and modern time, a review is given on nutritional significance of whey. The proteins are essential components of whey and belong to the proteins with highest biological value because of their amino acid composition. Besides, they show fundamental functional properties, which enable a varied application in foods, dietetic foods and beverages in form of different whey products (powder, protein concentrates and isolates). Whey proteins have found considerable usage in infant's nutrition as whey predominant formulas as well as whey protein hydrolysates in case of cow's milk protein intolerances. A recent field of research are biological active peptide sequences which become effective during digestion and are of importance for secretion of entero hormones as well as for immune enthancing effects. They may contribute to assess the biological value of whey proteins under enlarged points of view and to develop new application forms and areas. It is pointed to further fields of application (e. g. adipositas, gout, kidney insufficiency). Concerning the quantitatively most dominant lactose in whey, it is dealt with its importance for the healthy development of infants (adaptation to the increased lactose content of mother's milk) as well as with lactose intolerance and galactosaemia. In case of mineral salts of whey it is emphasized the high nutrient density of calcium (prophylaxis for osteoporosis), the beneficial Ca: P and Na: K proportions (antihypertensive in case of the last one), the promotion of absorption of mineral salts by lactose, and the high content of iodine. The whey is rich in B-vitamins, which contribute essentially for their satisfaction or requirement in case of a corresponding consumption. To be emphasized is the vitamin B₁₂ in milk and whey, which is the sole source of this indispensable nutrient for blood-formation and cell division in lacto-ovo-vegetarian nutrition. In conclusion, a summerizing dietetics valuation of whey is performed.     

正交试验优化喷雾干燥工艺制备香菇粉

以干香菇为原料,经过喷雾干燥制备香菇粉。通过单因素试验和正交试验来优化喷雾干燥的工艺参数,试验结果表明:在进风温度190℃、泵转速55 r/min、热空气流量0.23 m 3/min、麦芽糊精添加量50%的条件下,集粉率为37.65%,香菇粉持水力达到232.83 g/100 g,持油力为189.58 g/100 g。通过喷雾干燥制备的香菇粉,可作为调味料或原料添加到其他食品中。     

Effects of hydrolysis on solid-state relaxation and stickiness behavior of sodium caseinate-lactose powders

Hydrolyzed or nonhydrolyzed sodium caseinate-lactose dispersions were spray dried, at a protein: lactose ratio of 0.5, to examine the effects of protein hydrolysis on relaxation behavior and stickiness of model powders. Sodium caseinate (NC) used included a nonhydrolyzed control (DH 0) and 2 hydrolyzed variants (DH 8.3 and DH 15), where DH = degree of hydrolysis (%). Prior to spray drying, apparent viscosities of liquid feeds (at 70°C) at a shear rate of 20/s were 37.6, 3.14, and 3.19 mPa·s, respectively, for DH 0, DH 8, and DH 15 dispersions. Powders containing hydrolyzed casein were more susceptible to sticking than those containing intact NC. The former had also lower bulk densities and powder particle sizes. Scanning electron microscopy showed that hydrolyzed powders had thinner particle walls and were more friable than powders containing intact NC. Secondary structure of caseinates, determined by Fourier transform infrared spectroscopy, was affected by the relative humidity of storage and the presence of lactose as co-solvent rather than its physical state. Glass transition temperatures and lactose crystallization temperatures, determined by differential scanning calorimetry were not affected by caseinate hydrolysis, although the effects of protein hydrolysis on glass-rubber transitions (T(gr)) could be determined by thermo-mechanical analysis. Powders containing hydrolyzed NC had lower T(gr) values (~30°C) following storage at a higher subcrystallization relative humidity (33%) compared with powder with nonhydrolyzed NC (T(gr) value of ~40°C), an effect that reflects more extensive plasticization of powder matrices by moisture. Results support that sodium caseinate-lactose interactions were weak but that relaxation behavior, as determined by the susceptibility of powder to sticking, was affected by hydrolysis of sodium caseinate.     

乳清蛋白粉营养成分分析研究

目的分析不同批次乳清蛋白粉蛋白、脂肪、乳糖、维生素、矿物质及其他功能性营养素的含量及波动情况。方法依照国标方法对乳清蛋白粉营养成分进行检测,并对检测数据进行汇总,分析不同批次间乳清蛋白粉营养素指标的波动范围及相对标准偏差。结果不同批次间乳清蛋白粉营养素波动不大,部分维生素(维生素B12、叶酸、泛酸、维生素C)、矿物质(锌、镁)、功能性营养成分(α-亚麻酸、胆碱、左旋肉碱)相对标准偏差在15%以上,波动较大。结论乳清蛋白粉营养成分含量整体比较稳定。