抗结块新型精制盐工艺研究

氯化钠的结块问题始终困扰着生产厂家，也给使用者带来不便。目前国内外采取的方法主要是向产品中添加抗结块剂，但效果并不理想。本项研究提出一种全新的解决精制盐结块的方法。实验证明，本方法在解决了精制盐结块问题的同时，也使产品具有了更好的使用特性，是传统的精制盐工艺无法相比的。     

抗结块新型精制盐工艺研究

氯化钠的结块问题始终困扰着生产厂家,也给使用者带来不便。目前国内外采取的方法主要是向产品中添加抗结块剂,但效果并不理想。本项研究提出一种全新的解决精制盐结块的方法。实验证明,本方法在解决了精制盐结块问题的同时,也使产品具有了更好的使用特性,是传统的精制盐工艺无法相比的。     

调味盐的抗吸湿结块性能评价

研究通过检测结块率、结块强度、水分含量、吸湿率,对调味盐和未添加抗结剂食盐的抗结块性能进行对比分析,从而评价调味盐的抗吸湿结块性能。结果表明,未添加抗结剂食盐结块率、水分含量都随着加速时间的增加逐渐上升,而调味盐的结块率、水分含量都随着加速时间的增加几乎不变;调味盐和未添加抗结剂食盐在湿度小于75%时,都有很好的抗吸湿性能,在湿度大于75%时,随着时间的增加,调味盐的吸湿率比未添加抗结剂食盐增加得更慢。调味盐比未添加抗结剂食盐具有更好的抗吸湿结块性能。     

精制盐的抗结块研究

通过对盐结块机理以及影响盐结块因素研究分析,在逆向反循环真空蒸发制盐工艺的基础上,通过一定的生产工艺改进,生产大颗粒盐并使其大小均匀,从而不添加任何抗结剂防止盐的结块,满足各种盐产品需求。     

枣粉抗结块实验研究

为了防止枣粉结块,对影响其结块的去核干枣水分含量、磨粉环境相对湿度、抗结剂的种类及添加量、枣粉粒度、内包装方式等因素进行研究.结果表明,枣粉抗结的最佳工艺条件为去核干枣水分含量在3％以下,磨粉环境相对湿度控制在30％～35％,复合抗结剂为0.7％微晶纤维素+0.6％二氧化硅+0.7％磷酸三钙,枣粉的粒度为120目或140目,内包装充气量为30％.     

晶体类食品添加剂结块的成因与防止

晶体类物质往往存在结块问题,而结块问题又往往是影响产品质量的重要因素。本文简介了晶体类食品添加剂的结块现象对产品的危害和有关其结块机理的主要理论学说;并从结构理论、多晶现象、玻璃态转化和国内外对晶体类食品添加剂结块的研究成果等几个方面,较详细地分析了晶体类食品添加剂结块的成因及影响因素的影响概况;对国内外有关晶体类食品添加剂结块和防结块测定的评价进行了科学地概述;也针对有效预防晶体类食品添加剂结块提出了优化生产工艺参数、改善包装方式、合理使用防结块剂和科学设置贮藏条件等一系列具体的防止办法和措施;还就我国食品类防结块的形势作了简要展望。     

喷雾干燥条件对脱脂奶粉颗粒大小及其分布的影响

用显微镜、筛子和考特(Coulter)计数器三种仪器,对脱脂奶粉的颗粒大小及其分布进行了测定。显微镜法可以测得最小平均颗粒值,筛分法可以测得最大平均颗粒值。考特计数器法所使用的测定管,由于其孔径大小可稍作改变,故测得的结果也稍有不同。但是通常用这种方法测得的曲线,一般介乎显微镜法和筛分法所得的曲线之间。     

茶多糖铁的制备及盐用抗结块性能研究

制备和表征茶多糖-Fe复合物,并对其作为新型盐用抗结剂的性能进行了研究。通过红外光谱仪(IR)表征分析茶多糖-Fe的配位结构,利用扫描电子显微镜(SEM)、电子能谱仪(EDS)和X-射线衍射仪(XRD)对其抗结块机理进行了分析研究。实验结果表明:茶多糖-Fe是以醇羟基为主参与配位,其中铁是以聚合的β-FeOOH铁核结构存在。其作为盐用抗结剂具有良好的抗结块效果,在Fe含量为55 mg/kg时的结块率仅为29.92%。研究表明茶多糖-Fe的抗结块机理主要是其影响了盐晶粒表面的重结晶过程,改变了表面形态及晶体结构。     

鸡粉调味料工业化生产抗结块试验研究

采用静止角度测试法,在工业化条件下进行鸡粉调味料抗结块性能试验.考察了干燥温度、产品粒度、抗结剂添加量及蔗糖粉末添加量对鸡粉调味料抗结块性能的影响,并在单因素试验的基础上进行抗结块正交试验.结果表明,影响产品抗结块性能的因素从大到小依此为:蔗糖粉末添加量＞产品粒度＞干燥温度＞抗结剂添加量;最佳条件为:蔗糖粉末添加量4%(W:W),干燥温度90℃,产品粒度50目,抗结剂添加量0.50%(W:W).     

食用盐结块原理及不同材质外包装抗结块能力差异性分析

外包装一定程度上会影响食用盐的抗结块能力。文章对食用盐的基本结块原理进行分析,认为吸湿、放湿等是造成食用盐结块的最根本原理,对影响食用盐结块的因素包括粒度、对己量、杂质成分等因素进行总结,分析了在不添加抗结剂时,氧化膜、镀铝膜、铝箔膜等不同食用盐外包装抗结块能力的差异性,旨在为抗结块食用盐外包装开发提供借鉴。     

Dairy cow feeding system alters the characteristics of low-heat skim milk powder and processability of reconstituted skim milk

Low-heat skim milk powder (LHSMP) was manufactured on 3 separate occasions in mid lactation (ML, July 4–20) and late lactation (LL, September 27 to October 7) from bulk milk of 3 spring-calving dairy herds on different feeding systems: grazing on perennial ryegrass (Lolium perenne L.) pasture (GRO), grazing on perennial ryegrass and white clover (Trifolium repens L.) pasture (GRC), and housed indoors and offered total mixed ration (TMR). The resultant powders (GRO-SMP, GRC-SMP, and TMR-SMP) were evaluated for composition and color and for the compositional, physicochemical, and processing characteristics of the reconstituted skim milk (RSM) prepared by dispersing the powders to 10% (wt/wt) in water. Feeding system significantly affected the contents of protein and lactose, the elemental composition, and the color of the LHSMP, as well as the rennet gelation properties of the RSM. The GRO and GRC powders had a higher protein content; lower levels of lactose, iodine, and selenium; and a more yellow-green color (lower a* and higher b* color coordinates) than TMR powder. On reconstitution, the GRO-RSM had higher concentrations of protein, casein, and ionic calcium, and lower concentrations of lactose and nonprotein nitrogen (% of total N). It also produced rennet gels with a higher storage modulus (G′) than the corresponding TMR-RSM. These effects were observed over the combined ML and LL period but varied somewhat during the separate ML and LL periods. Otherwise, feeding system had little or no effect on proportions of individual caseins, concentration of serum casein, casein micelle size, casein hydration, heat coagulation time, or ethanol stability of the RSM at pH 6.2 to 7.2, or on the water-holding capacity, viscosity, and flow behavior of stirred yogurt prepared by starter-induced acidification of RSM. The differences in the functionality of the LHSMP may be of greater or lesser importance depending on the application and the conditions applied during the processing of the RSM.     

Comparison of casein micelles in raw and reconstituted skim milk

During the manufacture of skim milk powder, many important alterations to the casein micelles occur. This study investigates the nature and cause of these alterations and their reversibility upon reconstitution of the powders in water. Samples of skim milk and powder were taken at different stages of commercial production of low-, medium-, and high-heat powders. The nature and composition of the casein micelles were analyzed using a variety of analytical techniques including photon correlation spectroscopy, transmission electron microscopy, turbidity, and protein electrophoresis. It was found that during heat treatment, whey proteins are denatured and become attached to the casein micelles, resulting in larger micelles and more turbid milk. The extent of whey protein attachment to the micelles is directly related to the severity of the heat treatment. It also appeared that whey proteins denatured during heat treatment may continue to attach to casein micelles during water removal (evaporation and spray-drying). The process of water removal causes casein and Ca in the serum to become increasingly associated with the micelles. This results in much larger, denser micelles, increasing the turbidity while decreasing the viscosity of the milk. During reconstitution, the native equilibrium between colloidal Ca and serum Ca is slowly reestablished. The reequilibration of the caseins and detachment of the whey proteins occur even more slowly. The rate of reequilibration does not appear to be influenced by shear or temperature in the range of 4 to 40°C.     

营养强化剂对脱脂乳粉中甲醛产生的影响

目的 研究不同营养强化剂对脱脂乳粉中甲醛生成的影响.方法 脱脂乳粉添加5％有效含量的单一营养强化剂,经热处理后测定甲醛含量,进行单因素实验,考察不同营养强化剂对甲醛产生的影响,选择作用显著的营养强化剂进行双因素组合实验,研究不同营养强化剂之间的相互作用.结果 110℃热处理10 min的情况下,单因素实验结果表明,维生...     

Impact of source and level of calcium fortification on the heat stability of reconstituted skim milk powder

Calcium enrichment of food and dairy products has gained interest with the increased awareness about the importance of higher calcium intake. Calcium plays many important roles in the human body. Dairy products are an excellent source of dietary calcium, which can be further fortified with calcium salts to achieve higher calcium intake per serving. However, the addition of calcium salts can destabilize food systems unless conditions are carefully controlled. The effect of calcium fortification on the heat stability of reconstituted skim milk was evaluated, using reconstituted skim milks with 2 protein levels: 1.75 and 3.5% (wt/wt) prepared using low and high heat powders. Calcium carbonate, phosphate, lactate, and citrate were used for fortification at 0.15, 0.18, and 0.24% (wt/wt). Each sample was analyzed for solubility, heat stability, and pH. The addition of phosphate and lactate salts lowered the pH of milk, citrate did not have any major effect, and carbonate for the 1.75% protein samples increased the pH. In general, changes in solubility and heat stability were associated with changes in pH. Calcium addition decreased the solubility and heat stability. However, interestingly, the presence of carbonate salt greatly increased the heat stability for 1.75% protein samples. This is due to the neutralizing effect of calcium carbonate when it goes into solution. The results suggested that the heat stability of milk can be affected by the type of calcium salt used. This may be applied to the development of milk-based calcium enriched beverages.     

Biotransformation of isoflavone glycosides by Bifidobacterium animalis in soymilk supplemented with skim milk powder

ABSTRACT:  Two probiotic strains, Bifidobacterium animalis A and B, were used for the biotransformation of isoflavone glycosides in soymilk prepared from soy protein isolate (SPI) supplemented with skim milk powder (SMP) (SSMP). Unsupplemented soymilk (USM) and reconstituted skim milk powder (RSMP) were used as controls. The numbers of viable microorganisms in these products were enumerated. Lactose and isoflavone contents were quantified using high-performance liquid chromatography (HPLC). Our results showed that there was significantly higher biotransformation of isoflavone glycosides to aglycones in SSMP than that in USM. The levels of biotransformation were 83.96% and 85.43% for B. animalis A and B, respectively, compared to 74.30% and 72.82% for the USM. In addition, lactose utilization by both strains in SSMP was also higher than that in RSMP. At 24 h, 21.16 mg/mL of lactose was utilized in SSMP by B. animalis A compared with that of 16.88 mg/mL in RSMP. Consequently, the pH of SSMP was lower (3.80) than RSMP (4.00). However, the number of viable bacteria in SSMP was slightly lower than that in RSMP but significantly higher than that in USM. It appears that SMP enhanced the biotransformation of isoflavone glycosides to aglycones and SPI increased the lactose utilization by B. animalis A and B.     

Kinetics of available lysine in stored commercial skim milk powder at moderate temperatures

Kinetics of lysine blockage, as an early step of the Maillard reaction, was investigated in commercial skim milk powder to understand the extent of the reaction, specifically after packages are opened and during the subsequent storage. Samples were stored at six conditions including three temperatures (30, 32.5 and 35 °C) and two relative humidities (43% and 52%) for 30 days, the period in which the product is recommended to be consumed after opening. The reaction rate was determined using a dye‐binding method. Based on our findings, decrease in available lysine follows first‐order reaction kinetics model. Small changes in temperature (2.5 °C) caused significant increase in the reaction rate constants. Relative humidity affected temperature dependency of the reaction, and activation energies were estimated to be 142.5–170.8 kJ mol^?1. This study aims to increase the awareness of the significance of storage quality in relation to the nutritional status of the products.     

The composition of interfacial material from skim milk foams

The foaming properties of skim milk vary with temperature of foaming in the range from 5 to 85°C, with foams of maximum stability being formed at approximately 45°C. This paper reports the significance of different milk fractions in the foam and concludes that the micellar casein fraction plays an important role in stabilization of milk foam formed at higher temperatures. This finding was supported by the fact that added calcium chloride increased and calcium-chelating agents decreased foam stability. These effects were attributed to the increase and decrease, respectively, in the amount of micellar casein in the milk. Furthermore, bubble ghost material sedimented by low-speed centrifugation of foam was found to contain predominantly caseins, and electron micrographs of foams formed at 45°C clearly showed casein micelles spread over the interface. However, other structures observed in the electron micrographs suggest that soluble milk proteins and possibly polar lipids are also present in the foams and play a role in formation of milk foams.     

Isolation and partial characterization of CD36 from skim milk

CD36, a common milk fat globule membrane glycoprotein, was isolated from skim milk by methods similar to those previously utilized for the isolation of sulfhydryl oxidase. Two separate methods that were employed, gave similar purity as observed by electrophoresis. The first was based on differential centrifugation and size-exclusion chromatography, whereas the second combined ultrafiltration and affinity chromatography. After significant purification, the protein was identified by Western blotting and sequence analysis. Deglycosylation decreased the apparent molecular mass from approximately 85 to 57 kDa. These results suggested tissue-specific glycosylation. The purified fractions also exhibited low levels of sulfhydryl oxidase activity, the significance of which will require further study.     

Short communication: Proteins in heat-processed skim milk powder have no positive effects on bone loss of ovariectomized rats

Milk has positive effects on bone growth. However, the effect of skim milk powder (SMP) on bone properties has not been reported. This study investigated the effect of SMP on bone loss in ovariectomized (OVX) rats. Forty female Sprague-Dawley rats were ovariectomized and another 10 rats received a sham operation. The OVX rats were randomly separated into 4 groups: OVX control, OVX SMP1 (SMP at 0.04 g/d), OVX SMP2 (SMP at 0.20 g/d), and OVX SMP3 (SMP at 0.40 g/d). Skim milk powder was supplied in the rat diet for 12 wk, and the rats were gavaged once per day. The effects of SMP on calcium content and bone mineral density of femur were determined by atomic absorption spectrophotometry and dual-energy x-ray absorptiometry, respectively. Compared with the control, SMP at all dose levels tested had no particular effect on weight:length, calcium content, or bone mineral density of femurs. It was demonstrated that SMP (0.04 to 0.40 g/d) had no positive effect on bone loss in OVX rats, probably because the heat treatment used during SMP processing caused a loss of biological activity in the protein.     

Studies on the development of beverages using fruit juice/pulp, separated milk and reconstituted skim milk

Studies were carried out on the development of beverages using fruit juice/pulp, separated milk and reconstituted skim milk. Beverages were prepared by blending juice/pulp from apples, bananas, guavas, litchis and mangos at four different concentrations (100, 200, 300 and 400 g/L) with separated and reconstituted skim milk. Organoleptic evaluation of the beverages showed that apple juice and guava pulp could be blended at up to 300 and 100 g/L in milk products, respectively. Banana and mango pulp could also successfully be used at up to 200 g/L in separated milk and reconstituted skim milk. Litchi juice could be blended up to 300 g/L in separated milk and 200 g/L in reconstituted skim milk.