Effect of Agglomeration on Flowability of Baby Food Powders

Abstract: The aim of this study was to investigate the influence of the wet agglomeration in a fluidized bed on flowability of agglomerated products, such as baby food powders. The agglomeration process was performed in the fluidized bed. The wetting liquid used to the process was: water, 2% lecithin solution, and 50% sugar solution. Food powders flowability was expressed as: Hausner Ratio, pouring time, angles of sliding and of repose and flow function. The composition of materials, used to prepare mixtures, has a significant influence on tested properties. The higher milk powder of the mixtures caused decreasing of their flowability. Wet agglomeration of baby food powders caused an increase in the mean diameter of particles, which made it possible to receive agglomerates with good flowability and decreased bulk density. The increase of milk powder content from 0 to 73% in the mixture before the agglomeration contributed to improve its flowability. Wet agglomeration with 2% lecithin solution and 50% sugar solution reduced particle size and bulk density, improved flowability of received agglomerates in relation to agglomerates received with water as a wetting liquid. Practical Application: Agglomeration of baby food powders increases particle size of received agglomerates with a tendency to reduce their bulk density. Agglomerates flowability determined by using practical tests (Hausner ratio, pouring time, angles of sliding and of repose) is not sufficient for a comprehensive assessment of powdered deposit. For complex flow behavior, like that of agglomerated baby food powders, the Jenike shear test only remains as an acceptable test of flowability.     

Flowability and wetting behaviour of milk protein ingredients as influenced by powder composition,particle size and microstructure

This work aimed to provide a comprehensive characterisation of several physicochemical properties of different milk protein powders frequently used as ingredients in dairy‐based food formulations, in particular flowability and wettability. The flow and wetting properties were influenced mainly by the powder composition, less than by other physicochemical properties, such as particle size and microstructure. Powders with high fat content had poor flow and wetting properties. The wetting properties were also influenced by the protein content (mainly by the casein content) of the powders and were poor for powders having poor release of ionic calcium.     

Influence of protein content and storage temperature on the particle morphology and flowability characteristics of milk protein concentrate powders

Milk protein concentrate (MPC) powders are widely used as ingredients for food product formulations due to their nutritional profile and sensory attributes. Processing parameters, storage conditions, and composition influences the flow properties of MPC powders. This study investigated the bulk and shear flow properties of 70.3, 81.5, and 88.1% (wt/wt, protein content) MPC after storage for 12 wk at 25 and 40°C. Additionally, the morphological and functional changes of the MPC powders were investigated and correlated with flowability. After 12 wk of storage at 25°C, the basic flow energy values significantly increased from 510 to 930 mJ as the protein content increased from 70 to 90% (wt/wt). Flow rate index was significantly higher for samples with high protein content. Dynamic flow tests indicated that MPC powders with high protein content displayed higher permeability. Shear tests confirmed that the samples stored at 25°C were more flowable than samples stored at 40°C. Likewise, the higher-protein content samples showed poor shear flow behavior. The results indicated that MPC powders stored at 25°C had less cohesiveness and better flow characteristics than MPC powders stored at 40°C. Overall, the MPC powders had markedly different flow properties due to their difference in composition and morphology. This study delivers insights on the particle morphology and flow behavior of MPC powders.     

食品表面活性剂提升蛋白质粉溶解性的研究进展

蛋白质粉作为一种重要的食品营养与功能基料,在食品加工产业中应用场景广泛。然而在溶解过程中,由于界面效应所导致蛋白质粉结块、聚沉现象,使其溶解性降低,严重制约了食品蛋白质的应用及经济价值。食品表面活性剂可有效结合蛋白质粉,降低其溶解过程中发生的界面效应。因此,食品表面活性剂可更为广泛地应用于蛋白质粉溶解性能的提升。本文综述了食品表面活性剂的主要类型、与蛋白质结合的作用机制及对蛋白质粉溶解过程各阶段的影响,以期为食品表面活性剂在高溶解性蛋白质粉中的应用提供理论参考。     

Agglomeration of food powder and applications

Agglomeration has many applications in food processing and major applications include easy flow table salt, dispersible milk powder and soup mix, instant chocolate mix, beverage powder, compacted cubes for nutritional-intervention program, health bars using expanded/puffed cereals, etc. The main purpose of agglomeration is to improve certain physical properties of food powders such as bulk density, flowability, dispersability, and stability. Agglomerated products are easy to use by the consumers and hence are preferred over the traditional non-agglomerated products that are usually non-flowable in nature. The properties of food agglomerates and the process of agglomeration like employing pressure, extrusion, rewetting, spray-bed drying, steam jet, heat/sintering, and binders have been reviewed. The physical and instant properties of agglomerated food products have also been discussed.     

Empirical Model for Water Uptake and Hydration Rate of Food Powders by Sorption and Baumann Methods

The empirical model q = Q t/B + t, where q is the amount of water taken up at time t was useful to describe water uptake of several food powders determined either by the Baumann or the sorption isotherm method at 75.6 and 100% RH. The equilibrium values (Q) and the specific rate constant (K) derived from this model as (QB)^-1 could be used to characterize food materials for hydration capacity and rate. Large differences were observed in Q values between methods and between food powders. The Baumann Q values and sorption isotherm Q values at 100% RH ranked similarly water takeup of food powders (R = 0.97, p < 0.001). Baumann K values and sorption isotherm K values at 100% RH also correlated highly. However, little differences were observed among the K and Q values of different food powders determined by the sorption isotherm method at 75.6% RH.     

Flow Properties of Commonly Used Food Powders and Their Mixtures

The aim of this study was to get an insight on flow properties of five different food powders and their mixtures frequently used in industrial production of foodstuffs and in households. The studied food powders were flour, maize semolina, sugar, cocoa, and skim milk powder together with their mixtures. Based on cohesion index, samples were categorized as follows: easy flowing—sugar powder, skim milk powder, maize semolina, and mixture 3 (wheat flour and sugar powder); cohesive—flour and mixture 1 (wheat flour and maize semolina); very cohesive—mixture 4 (wheat flour, cocoa, and sugar powder), and extremely cohesive—cocoa powder and mixture 2 (cocoa, sugar, and skim milk powder). Based on powder flow speed dependency test, positive multiple correlations were found between four powder mixtures and their basic components at all speeds. Flour, maize semolina, and mixtures 1 and 3 did not show any susceptibility to caking, while sugar, skim milk powder, cocoa powder, and mixtures 2 and 4 showed an increasing cake height ratio indicating their susceptibility to caking.     

Roles of Water and Solids Composition in the Control of Glass Transition and Stickiness of Milk Powders

Abstract: Plasticization and glass transition of amorphous components in food powders often result in stickiness and caking. The glass transition temperature (T_g) of milk powders was measured by differential scanning calorimetry (DSC) and a viscometer method was used to determine sticky-point temperatures. Water sorption isotherms were established for varying solids compositions. Lactose contents were analyzed by high-performance anion exchange chromatography with pulsed amperometric detection (HPAE-PAD) and proteins were identified using SDS-PAGE gel electrophoresis. Solids composition and water affected both the T_g and stickiness behavior. Stickiness was governed by carbohydrates and water plasticization. At low protein contents, precrystallization of lactose decreased the sticky point temperature, but increasing protein content in all milk powders decreased stickiness at all water activities. The results showed that glass transition can be used to describe time-dependent stickiness and crystallization phenomena, and it can be used as a parameter to control and reduce stickiness of dairy solids with various compositions. Practical Application: Glass transition of component sugars in milk powders with various water contents was responsible for a solid-liquid transformation which resulted in their viscous flow at particle surfaces and stickiness of the powders. Stickiness leads to wall deposition in dehydration and caking of powders in storage when the amorphous carbohydrate-rich components gain liquid characteristics. High protein contents in milk powders decreased stickiness, but precrystallization of lactose prior to spray drying increased stickiness at low protein content. Milk powders in storage gained higher water contents with increasing protein contents, but stickiness was reduced and lactose crystallization was delayed which improved storage stability.     

A review on flow characterization methods for cereal grain‐based powders

Flow difficulties during handling, storage, and processing are common in cereal grain‐based powder industries. The many studies that focus on the flow properties of powders can be classified as flow indicators, shear properties, and dynamic flow properties. The non‐uniformity of physical and chemical characteristics of the individual particles that make up the bulk solid of cereal grain‐based powders adds complexity to the characterization of flow behavior. Even so, knowledge of flow behavior is critical to the design of productive and cost‐effective equipment for handling and processing of these powders. Because many factors influence flow, a single property/index value may not satisfactorily quantify the flow or no‐flow of powders. For powders of biological origin, chemical composition and environmental factors such as temperature and relative humidity complicate flow characterization. This review focuses on the specific flow characteristics that directly affect powder flow during handling, processing, and storage. © 2015 Society of Chemical Industry     

涡街流量计在计量中的运用

介绍了一种适用于测量液体、气体和蒸汽流量的仪表---涡街流量计,针对涡街流量传感器的工作原理、特点及其选型原则、安装方式、配管等方面进行说明,并对管径大小、测压点和测温点位置等影响仪表精度的因素给出了安装示意图和规范的具体数字,在参数相对应等调试方面及在使用过程中防止管道振动和信号干扰等问题提出具体的解决措施。     

制备方法对山楂果胶理化特性的影响

山楂果胶作为一种纯天然的食品添加剂,在食品生产和加工中起着重要作用。本实验采用热风干燥和冷冻干燥两种不同的干燥方法以及研磨、剪切、气流3 种不同的粉碎方法来处理山楂,得到6 种山楂粉,进而对山楂粉热特性进行分析,并以山楂粉为原料进行山楂果胶的提取,同时通过半乳糖醛酸质量分数、总糖质量分数、酯化度测定和傅里叶变换红外光谱、X射线衍射、流变学分析对不同方法制备的山楂果胶理化特性进行比较。结果表明：不同处理条件的山楂粉热特性并未表现出明显差异,冷冻干燥组果胶得率和半乳糖醛酸质量分数均高于热风干燥组。同种干燥方法不同粉碎方法对山楂果胶的理化性质影响总体差异不显著（P＞0.05）,同种粉碎方法不同干燥方法处理下,冷冻干燥组的各项理化性质显著优于热风干燥组（P＜0.05）。本实验可为实际生产山楂果胶产品提供理论参考。     

Glass transition and caking of spray-dried lactose

Simple test methods to determine the onset temperatures of viscous flow and caking of spray-dried amorphous lactose are described. The extent of viscous flow was measured as an increase in the density of lactose plugs within a cylindrical aluminium compaction apparatus after incubation for 3h at a specified temperature. Caking was characterized by an increase in the hardness of the lactose plugs formed. The onset temperature of viscous flow decreased with increasing water activity, A_w, and corresponded to the onset temperature of glass transition, T_g1. Glass transition temperatures were determined using both differential scanning calorimetry (DSC) and nuclear magnetic resonance (NMR) spin relaxation. The results suggest that elevation of the powder temperature above T_g1 promotes viscous flow and increases the potential for caking of amorphous food powders.     

Flow Properties of Spray-Dried Encapsulated Butteroil

The interdependence of physical properties of spray-dried butteroil encapsulated in sucrose, lactose or all-purpose flour were evaluated and compared to those of common powders such as spray-dried nonfat dry milk, whole milk powder, and sodium chloride. Powders were evaluated in terms of flow (mass flow rate and angle of repose), bulk (density) and mechanical properties (compressibility and stress relaxation). The powders were classified into three groups by mechanical sieving based on size as: “small particles” (>210 μm), “particles” (+210–420 μm) and “encapsulated particles” (+210–500 μm). The flow and mechanical behavior of encapsulated powders were different (P < 0.05) from the other powders. Encapsulated powders were less flowable (P < 0.05) but the addition of 2% anti-caking/flow agent enhanced flow characteristics.     

血糖仪应用于食品检测的研究进展

血糖仪是一种测量血糖水平的电子仪器,由于其具有快速、便捷、成本低、易于操作等特点,在临床中受到了广泛的关注。近年来以血糖仪为基础,结合多种识别机制和信号转导及放大策略,实现了多种非糖目标物的定量分析。本文概述了血糖仪的发展历史,重点综述了血糖仪在食品检测领域的应用,并对其研究前景进行了展望。     

先进的原奶管理方案 DIESSEL乳品的固定式和移动式收集系统

<正> 在牛奶的冷链工程中,一个重要的环节就是收集和输送。目前国内该环节普遍比较薄弱,仅有泵/手动取样/称重等简单功能,各项数据的统计也很分散和缓慢。随着我国乳品行业的发展,也对该环节提出了更高的要求。德国DIESSEL迪塞尔公司提供的一种乳品收集解决方案。     

FUNCTIONALITY COMPARISON BETWEEN DERIVATIZED WHEY PROTEINS AND A PREGELATINIZED STARCH

A process has been patented to produce stabilizing ingredients from whey proteins which are applicable over a wide range of typical food conditions and do not require heat or the addition of salts to induce thickening functionality. Once reconstituted in deionized water, solutions were evaluated and compared with water holding performance and rheological attributes of a pregelatinized cornstarch. Rotational viscometry was performed at pH values between 3 and 8, temperatures between 5 and 90C, and shear rates between 1 and 100 s⁻¹. Derivatized whey protein powders and pregelatinized starch displayed pseudo-plastic behavior under shear at all temperatures tested. During temperature ramps from 5 to 90C, derivatized whey protein flow properties were essentially unchanged by varying pH. However, viscosity after the temperature increase was higher than initial values, possibly due to additional protein denaturation and hydrophobic interactions. Derivatized powders were stable and retained desired functionality over a wide range of food processing and preparation conditions and may therefore possess applicability to many products currently utilizing modified starches or hydrocolloids to texturize.     

Comparison of 2 types of milk flow meters for detecting bimodality in dairy cows

The primary objective of this observational study was to investigate whether incremental milk flow rates (in the 0–15 s, 15–30 s, 30–60 s, and 60–120 s intervals) from electronic on-farm milk flow meters can be used to detect bimodal milk flow curves in dairy cows compared with the use of a portable milk flow meter. Our second objective was to study the concordance between an electronic on-farm milk flow meter and a portable milk flow meter for assessing the 2-min milk yield and total milk yield. In this cross-sectional study, data from 92 milking observations from individual cows were analyzed. We collected data on incremental milk flow rates, the 2-min milk yield, and the total milk yield simultaneously with an on-farm milk flow meter and a portable milk flow meter. Bimodality detected by the on-farm milk flow meter was defined as lower milk flow rates during any of the 15–30 s, 30–60 s, and 60–120 s intervals compared with the previous intervals (0–15 s, 15–30 s, and 30–60 s). Bimodality according to the portable milk flow meter (BIM_LC) was observed through automatic detection. κ statistics indicated good agreement between bimodality detected by the on-farm milk flow meter and BIM_LC [κ (95% confidence interval): 0.69 (0.49–0.90)]. Using BIM_LC as the gold standard, diagnostic test statistics for bimodality detected by the on-farm milk flow meter indicated moderate performance for sensitivity [0.73 (0.54–0.86)] as well as high performance for positive predictive value [0.83 (0.63–0.93)], specificity [0.94 (0.85–0.98)], and negative predictive value [0.90 (0.81–0.95)]. Receiver operating characteristic curve analyses revealed that the 30–60 s milk flow rate was the variable that best predicted BIM_LC, yielding an area under the curve of 0.89. Pearson correlation coefficients (r) revealed a very strong correlation between the 2 devices for both the 2-min milk yield [0.97 (0.96–0.98)] and total milk yield [r (95% confidence interval), 0.97 (0.96–0.98)]. Additionally, intraclass correlation coefficients (ICC) and concordance correlation coefficients (CCC) indicated excellent agreement between the 2 devices for the 2-min milk yield [ICC, 0.97 (0.96–0.98); CCC, 0.94 (0.92–0.96)] and total milk yield [ICC, 0.97 (0.96–0.98); CCC, 0.97 (0.95–0.98)]. Therefore, we concluded that electronic on-farm milk flow meters that measure incremental milk flow rates can be used to detect bimodality in dairy cows and that on-farm milk flow meters facilitate precise measurements of the 2-min milk yield and total milk yield.     

食品粉粒体混合:混合机理与混合均匀度影响因素探讨

将单体营养强化剂或预混的多种营养强化剂按要求加入到某种食物载体中即为食物强化.食物强化是营养干预的主要手段.粉粒体状食物的强化要求营养强化剂在食物载体中应均匀分布.粉粒体状强化食品的生产是一个基于多种不同物性颗粒粉体混合的复杂过程,明晰粉粒体混合的基本原理及易造成粉粒体混合物分级的主要原因,能够为生产合格的粉粒体状强化食品奠定重要技术基础.本文综述了对流混合、扩散混合、剪切混合等粉体混合理论,并分析了三种混合机理在混合过程中的作用,探讨了粉体颗粒个体的粒径、形状、密度及水分含量等因素对粉体混合均匀度的影响,经比较分析后认为粉体颗粒粒径差异造成的影响最为显著,这可能是因为粉体颗粒粒径指标的差异倍数远远大于颗粒个体在形状、密度等其它指标上的差异.     

Caking of lactose: A critical review

BackgroundCaking is a recurrent problem in various industries, whether it occurs during the production, storage or transport of powders. Caked powder results in longer processing times and decreased product quality, leading to significant economic loss. Several caking mechanisms have been described in the literature. However, they are often difficult to take into account in an industrial context, given the many parameters which influence the overall caking phenomenon.Scope and approachThis review describes the three relevant caking mechanisms for food powders in general. Focussing on predominantly crystalline lactose powder, we discuss how each of these mechanisms can explain caking and be prevented in the industrial context. The second part of this paper presents a critical review of the methods used to characterise caking to date.Key findings and conclusionsThe presence of amorphous material and other impurities must be assessed in crystalline lactose powders, as they can trigger amorphous and humidity caking. Particle size distribution is another key parameter requiring control as it can encourage caking through enhancement of particle interactions. In general, preventing caking in food powders can only be achieved by a thorough understanding of the production process and storage conditions. Moreover, the characterisation of caking remains a challenge as most methods published in the literature do not fit the needs of the food industry. The real demand is for a reliable method to predict caking which would be rapid and easy enough to be applied to each batch for quality control.     

Recent advances in processing food powders by using superfine grinding techniques: A review

Food powders are ubiquitous in people's daily life and food industry production with numerous advantages. With the increasing use of food powder in the world, it is increasingly important to understand the processing methods of food powder and the changes in physicochemical properties after processing in order to control the processing conditions and the quality of final products. Among the many processing methods for food powders, superfine grinding technique is an emerging and useful tool for superfine powder manufacturing with some unique and promising properties, which has made the technique successfully applied in food processing over the recent decades. This review highlights the information of the main superfine grinding methods in the field of food processing and the changes in performance after superfine grinding treatment. Also, potential challenges, promising opportunities, and perspectives of this technology are covered in the review. This review will provide theoretical foundation and guideline for superfine food powder processing, which can provide new approaches and ideas for the high‐value utilization of food raw materials as well as the food design.