Formation of sunflower oil emulsions stabilized by whey proteins with high-pressure homogenization (up to 350 MPa): effect of pressure on emulsion characteristics

A new ultra-high-pressure homogenizer was used to make very fine oil in water emulsions. The effect of pressures up to 350 MPa on sunflower oil (20%) in water emulsions was studied. The emulsifier used was whey protein concentrate (1.5%). The properties of the emulsions were characterized by laser light scattering (droplet size distribution) and coaxial cylinders rheometry (rheological behaviour). The protein adsorption fraction was obtained by a spectrophotometric method using bicinchoninic acid reagent.
Significant modifications in the structure and the texture of the emulsions were observed as the pressure increased. No change was revealed by polyacrylamide gel electrophoresis of the whey protein within the pressure range studied. Microdifferential scanning calorimetry scans indicated that the changes of the structural and textural properties may be because of changes in the protein conformation.     

Production of fine emulsions at pilot scale for oil compounds encapsulation

Feasibility of producing, at pilot scale (5 kg), stable oil in water emulsions with size of 1–2 μm and 100–200 nm was investigated in relation with the oil content of the emulsion (4%, 8% and 12% w/w) and with the composition of the aqueous phase.     

Theoretical and experimental analyses of drop deformation and break-up in a scale model of a high-pressure homogenizer

High-pressure homogenizers (HPHs) are used to create sub-micron emulsions in low-viscosity fluids. As the flow in a real HPH is very extreme, with gaps ranging from 10 to 100 μm and high velocities, it is almost impossible to visualize the drop break-up process. In this study a plastic scale model of a HPH was made, allowing the visualization of drop deformation and break-up. Great care was taken to keep the relevant dimensionless numbers constant during the scaling-up. The experimental data were interpreted in terms of theoretical drop break-up theory. It was found that both viscous and inviscid mechanisms can deform the drop. When a drop is exposed to a high-energy eddy, the deformation process proceeds rapidly. The deformed drop offers very little resistance to the eddies surrounding it, and it is drawn out, coiled and finally broken up into smaller droplets of various sizes.     

中、小型豆乳加工设备的研制

本文介绍了一种中、小型豆乳加工设备。该加工设备主要由小型房装机、均质机和贮罐组成,其均质机集均质、乳化、脱臭和杀菌诸功能于一身。该机组简单、实用、价廉,用它生产豆乳成本低,质量好,是实施国家教委"豆奶工程"较理想的豆奶加工设备。     

Electrospraying of water in oil emulsions for thin film coating

Electrospraying of water-in-oil emulsions was investigated to produce thin edible barriers. A reproducible model surface was used, namely cellulose membranes of which permeability is well-established. PGPR-based emulsions were stable during electrospraying and produced a fine stable jet spray; emulsions prepared with lecithin and span80 produced unstable jets and only sporadic sprays. The droplet size decreased to 50 ± 10 μm by the addition of water droplets till 3% but remained constant at higher water volume fractions. On the other hand, the addition of protein and salt influenced the droplet size and radius values up to 200 μm were found. The addition of whey protein isolate (10% w/w) resulted in films with water vapour barrier properties that were at least 70% better than lipid only, therewith showing that addition of protein enhances the integrity of the films.     

Effect of heat treatment on the properties of soy protein‐stabilised emulsions

The effect of heat treatment on the properties of soy protein‐stabilised emulsions was investigated. Emulsions were prepared with unheated and heat‐treated soy protein (NSP and HSP) dispersions. Heating on soy protein dispersions at 95 °C for 30 min resulted in smaller average oil droplet size, lower tendency for oil droplet flocculation, higher protein adsorption and lower viscosity. The properties of emulsions were significantly influenced by the protein concentration. The sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE) profiles showed that the heat treatment on soy protein dispersions increased the protein adsorption at O/W interface. The viscosity of all samples at low shear rate was inversely proportional to the d₃₂, suggesting a positive relation to the total interfacial area per unit volume. Emulsions showed shear‐thinning behaviour. The relaxation time was found to increase with aqueous phase viscosity determined by the Cross viscosity model.     

Influence of pH on linear viscoelasticity and droplet size distribution of highly concentrated O/W crayfish flour-based emulsions

In the present work, the influence of pH on stability of oil-in-water (O/W; 75 wt%/25 wt%) emulsions stabilized by crayfish flour (CF) has been studied. CF (containing ca. 65 wt%) showed poor functionality in a wade range of pH, which inhibits formation of stable emulsions. An indirect procedure has been developed in order to obtain emulsion at a broad pH range, including isoelectric point (pI) value. The emulsions have been characterized by means of linear dynamic viscoelasticity and droplet size distribution (DSD) analysis. These emulsions present a behaviour characteristic of highly concentrated emulsions with a well-developed plateau region. The most unfavourable DSD and linear viscoelastic results correspond to the pI. A significant improvement takes place as the pH value departs from the pI. An exception for linear viscoelasticity results have been found at pH 10, which is close to the pI for rod segments of myofibrillar proteins. Stability of these emulsions has been studied by following the evolution of DSD and linear viscoelastic parameters along time. The poorer results in emulsion stability correspond to pH values close to the pI, at which the increase in droplet size or uniformity parameter as well as the decrease in the plateau modulus become more pronounced. Conversely, the stability significantly improves as the pH departs from pI.     

Effect of heat treatment and droplet size on the oxidative stability of whey protein emulsions

The present paper examines whether certain processing factors may influence the oxidative stability of whey protein oil-in-water emulsions, which are structurally close to innovative industrial products (e.g. “fresh-cheese” and “non-dairy cream” types).     

Effect of concentrated flaxseed protein on the stability and rheological properties of soybean oil-in-water emulsions

Flaxseed protein concentrate containing-mucilage (FPCCM) was used to stabilize soybean oil-in-water emulsions. The effects of FPCCM concentration (0.5, 1.0, 1.5% w/v) and oil-phase volume fraction (5, 10, 20% v/v) on emulsion stability and rheological properties of the soybean oil-in-water emulsions were investigated. Z-average diameter, zeta-potential, creaming index and rheological properties of emulsions were determined. The result showed that FPCCM concentration significantly affected zeta-potential, creaming rate and emulsion viscosity. The increasing of FPCCM concentration led to a more negative charged droplet and a lower creaming rate. Oil-phase volume fraction significantly affected Z-average diameter, rheological properties, creaming index and creaming rate. With the increase of oil-phase volume fraction, both Z-average diameter and emulsion viscosity increased, while creaming index and creaming rate decreased. The rheological curve suggested that the emulsions were shear-thinning non-Newtonian fluids.     

各相体积比对W/O/W复合乳状液性质的影响

目的：研究用两步乳化法制备W／O／W型复合乳状液时，第一相体积比（内水相与油相的体积比）、第二相体积比（初乳与外水相的体积比）对W／O／W型复合乳状液性质的影响；方法：采用两步乳化法制备W／O／W型复合乳状液，固定制备工艺条件，改变第一相体积比和第二相体积比的数值制备初乳和复乳，用离心分层稳定性评价复乳的稳定性，初乳的离心稳定性、黏度和复乳的粒度分布被测定；结果：随着第一相体积分数增大，初乳黏度增大，初乳和复乳的离心稳定性都提高，但是内水相的体积分数达到65％时，初乳表现出凝胶的外观，所制备的复乳的稳定性反而降低，当内水相的体积分数增加到70％的时候，初乳转相形成O／W型乳状液，不能进一步制备复乳；随着第二相体积分数的增大，复乳黏度线性增大，复乳滴的体积平均粒径减小，复乳的离心稳定性提高。初乳中内水相与油相的适宜的体积比及复乳中初乳和外水相的适宜体积比皆为1：1左右。     

酸浸加压软化法制备鱼鳞粉工艺的研究

研究用酸浸加压软化法制备鱼鳞粉过程中主要因素对其工艺及产品质量的影响,采用通用旋转组合设计和响应面法优化最佳工艺参数.结果表明,其优化参数为:软化压力0.074 MPa、软化时间104 min、乳酸浓度10.6%、液料比为6.1:1(v:m),在此工艺条件下进行验证试验,测得羟脯氨酸、游离氨基酸、钙含量和鱼磷粉得率的综合指标为3.481,与预测值3.479较为吻合.     

Rheological behavior and stability of d-limonene emulsions made by a novel hydrocolloid (Angum gum) compared with Arabic gum

Our goal was to evaluate emulsion stability, droplet size analysis and rheological behavior of the emulsions prepared by a native biopolymer namely Angum gum (An) compared with Arabic gum (Ar) stabilized emulsions. After gum extraction, gum dispersions with maltodextrin were prepared in water (in 1-5% concentrations) and emulsified with 5% and 10% d-limonene using high pressure homogenization. Statistical analysis revealed a significant influence of gum type and gum concentration on emulsion stability at α = 0.05. Flavor level was not important statistically in emulsion stability but it was the only factor with a significant influence (P < 0.05) on surface tension of the emulsions. The results showed that Angum gum was superior to Arabic gum in stabilizing emulsions during storage. Also, rheological data revealed that Angum gum-emulsions’ behavior was following the Herschel-Bulkley model with higher viscosities compared to Arabic gum emulsions, which could be the main reason of higher emulsion stabilities with this novel hydrocolloid.     

Effects of protein concentration and oil-phase volume fraction on the stability and rheology of menhaden oil-in-water emulsions stabilized by whey protein isolate with xanthan gum

The influences of protein concentration (0.2, 1, 2 wt%) and oil-phase volume fraction (5%, 20%, 40% v/v) on emulsion stability and rheological properties were investigated in whey protein isolate (WPI)-stabilized oil-in-water emulsions containing 0.2 wt% xanthan gum (XG). The data of droplet size, surface charge, creaming index, oxidative stability, and emulsion rheology were obtained. The results showed that increasing WPI concentration significantly affected droplet size, surface charge, and oxidative stability, but had little effect on creaming stability and emulsion rheology. At 0.2 wt% WPI, increasing oil-phase volume fraction greatly increased droplet size but no significant effect on surface charge. At 1 or 2 wt% WPI, increasing oil-phase volume fraction had less influence on droplet size but led to surface charge more negative. Increasing oil-phase volume fraction facilitated the inhibition of lipid oxidation. Meanwhile, oil-phase volume fraction played a dominant role in creaming stability and emulsion viscosity. The rheological data indicated the emulsions may undergo a behavior transition from an entropic polymer gel to an enthalpic particle gel when oil-phase volume fraction increased from 20% to 40% v/v.     

一种基于改进的YOLOv3算法在粮虫小目标检测的应用

原始YOLOv3模型被认为适合求解多尺寸的图像目标检测问题,但是对于粮虫小目标检测存在表征能力不足且检测效率较低的问题。本文基于此提出了一种融合GIoU算法的YOLOv3检测模型,一方面使用GIoU算法弥补IoU算法对于两个不相交box无法进行量化的问题,同时使用GIoU对损失函数进行优化,损失函数优化为GIoU损失、置信度损失和分类损失三方面;另一方面使用五种数据增强手段对原始1 998张数据集进行数据增强,最终形成大小为9 990张的数据集,并使用K-means聚类算法对自制数据集进行聚类分析,聚类出符合粮虫小目标检测的先验框。针对自制的9 990张粮虫的数据集进行实验获得了99.43%的mAP和每幅图像0.040 s的检测速度,与原始YOLOv3模型相比,本文所提模型对于小目标的粮虫检测效果得到了很大的提升。     

改良型氧化沟工艺处理碱法草浆中段废水

介绍了采用FAS-Jet射流曝气系统的改良型氧化沟系统处理碱法草浆中段废水的设计及启动调试。改良型氧化沟采用全好氧曝气,沟中不存在缺氧区和厌氧区;氧化沟兼有完全混流式和推流式的独特水力特征,抗冲击能力强;FAS-Jet系统氧转移效率高、污泥沉淀性能好。运行结果表明,此工艺及参数选择合理、运转稳定,出水水质可达到造纸工业水污染物排放的国家标准。     

基于贝叶斯方法的山羊绒与细羊毛的鉴别

根据细羊毛与山羊绒的鳞片形状与结构特征的不同,提出智能识别2类纤维的方法。通过CCD系统获取2类纤维的灰度图像,采用图像技术将灰度图像处理成单像素宽度的二值图,从二值图中提取描述2类纤维鳞片形状特征的4个比对指标。在样本数据库上基于4个比对指标的统计假设建立辨识细羊毛与山羊绒纤维的贝叶斯分类模型。仿真结果表明:该模型具有较好的纤维鉴别能力,对山羊绒纤维的识别准确度达到83%,对细羊毛则达到90%;并且随着参数的增加,模型有进一步提高鉴别精度的可能。     

基于改进Canny算子的葵花籽边缘检测方法

针对葵花籽一类不规则形体的边缘检测问题,采用传统的Canny算法有许多局限。文章对其提出三点改进:1基于梯度统计差分的自适应阀值法,克服了传统算法在目标与背景灰度变化较大时边缘检测会丢失部分边缘的不足,有效提高信噪比;2基于梯度方向的端点延伸法,弥补了Canny算法在连接分析后得到较多断线边缘的缺陷;3基于最长曲线的区域包围法,可去除背景中短小边缘,从而去除目标外围的干扰,实现葵花籽区域的精确定位。试验结果证明,在高复杂背景下改进的Canny算法在葵花籽边缘检测上取得了很好的效果。     

Process improvement for semipurified oleosomes on a pilot-plant scale

Semipurified oleosomes were isolated on a pilot-plant scale using improved-process extraction conditions. The improved process consisted of continuous centrifugation in a three-phase decanter with recirculation of slurry until most of the oleosomes were recovered. Oleosome fractionation, oleosin identification, and isoflavone and saponin mass distributions and recoveries were investigated. The improved pilot-plant oleosome extraction process was achieved in 8 h. A total of 91%± 1% of soybean oil was recovered as intact oleosomes. The oil content of the aqueous supernatant and the residue fractions were low at 2% and 3%, respectively. The aqueous supernatant fraction contained 40% total soybean protein. About 76% of the proteins present in the oleosome fraction were soybean storage proteins. Washing the semipurified oleosomes with a 0.1 M Tris-HCl, pH 8.6 containing 0.4 M sucrose, and 0.5 M NaCl resulted in the recovery of the associated storage proteins. The recovery of these proteins in addition to the protein in aqueous supernatant accounted for 79% of the total soybean storage proteins fractionated by this process. Oleosins were detected at 17 and 18 kDa. Isoflavones and saponins partitioned into the oleosome, aqueous supernatant, and residue fractions at different ratios with the majority, about 82 and 63 mole%, respectively, in oleosome and aqueous supernatant fractions, making these fractions an attractive source for phytochemicals.     

依靠集成创新,提高我国造纸装备的整体水平 谈3150/1000文化纸机国产化成套设备的设计研制

《轻工业调整和振兴规划》明确提出：＂造纸装备重点发展大幅宽、高车速造纸成套设备＂,＂重点行业装备自主化水平稳步提高,中型高速纸机成套装备实现自主化＂,＂建立造纸技术创新联盟＂……。辽阳造纸机械股份有限公司、河南江河纸业有限公司是这一政策的先行先试者,两企业强强联合,优势互补,具备了较强的集成创新能力和一定的自主创新能力,成功设计开发制造出3150/1000文化纸机国产化成套设备。这一成套设备的推广应用,必将加快提升我国制浆造纸装备的国产化水平,标志着我国造纸装备业的整体技术进入了一个新的发展阶段。     

锤片粉碎机气力输送系统的试验研究

设计的锤片粉碎机气力输送系统试验台,在粉碎机机壳的四个不同位置设置了进风口,采用孔径为0.7 mm(开孔率5.15%)和1 mm(开孔率7.92%)筛板,用玉米进行粉碎试验的结果表明,根据粉碎机机型设计合适的机壳进风口和可调节进风口面积的结构,并且在气力输送系统中安装参数检测装置,使锤片粉碎机的气力输送系统能够适应饲料原料多品种和不同粉碎成品粒度的要求。