Water droplet spreading and recoiling upon contact with thick-compact maltodextrin agglomerates

BACKGROUND: The food and pharmaceutical industries handle a number of compounds in the form of agglomerates which must be put into contact with water for rehydration purposes. In this work, liquid‐solid interaction between water and maltodextrin thick–compact agglomerates was studied at different constituent particle sizes for two compression forces (75 and 225 MPa). RESULTS: Rapid droplet spreading was observed which was similar in radius to the expected one for ideal, flat surfaces. Contact angle determinations reported oscillations of this parameter throughout the experiments, being indicative of droplet recoiling on top of the agglomerate. Recoiling was more frequent in samples obtained at 225 MPa for agglomerate formation. Agglomerates obtained at 75 MPa exhibited more penetration of the water. Competition between dissolution of maltodextrin and penetration of the water was, probably, the main mechanism involved in droplet recoiling. Micrographs of the wetting marks were characterized by means of image analysis and the measurements suggested more symmetry of the wetting mark at higher compression force. CONCLUSION: Differences found in the evaluated parameters for agglomerates were mainly due to compaction force used. No significant effect of particle size in recoiling, penetration of water into the agglomerate, surface texture and symmetry was observed. Copyright © 2011 Society of Chemical Industry     

ATTRITION EVALUATION FOR SELECTED AGGLOMERATED FOOD POWDERS: THE EFFECT OF AGGLOMERATE SIZE AND WATER ACTIVITY

Investigation of the attrition of agglomerates is very important for assessing the agglomerate strength, compaction characteristics, and quality control. A one‐term exponential attrition index model and the Hausner ratio were used to study the effects of agglomerate size and water activity on the attrition kinetics of some selected agglomerated food powders. It was found that the agglomerate size and water activity played significant roles in affecting the attrition: the larger the agglomerate size and the higher the water activity, the higher the attrition index under the same tap number. The Hausner ratio was well correlated with the attrition index at high tap numbers and might be used as a simple index to evaluate attrition severity for agglomerates. Knowing the effects of agglomerate size and water activity is very useful to minimize the attrition phenomenon during the handling and processing of agglomerated powders.     

Effect of pneumatic conveying parameters on physical quality characteristics of infant formula

The geometry and operating conditions of a pneumatic conveying rig for infant formula were varied according to an L₁₈ orthogonal array, with the goal of minimising variations in four product quality characteristics: bulk density, volume mean diameter, particle density and wettability. A modular pneumatic conveying rig was fabricated from 316L stainless steel components. The factors that were varied in these experiments included mode of conveying, air velocity, number of rig passes, bend radii and vertical rig section length. A factorial analysis of variance showed that the mode of conveying, air velocity and number of passes had a statistically-significant effect on bulk density. The optimum settings to minimise variability were dense phase conveying with a 50 mm plug length, 960 mm vertical section, 3 m/s air velocity, 2 passes and 50 mm bend radii, assuming a linear model. The bulk density change at these optimum settings was negligible at 0.9%.     

福瑞鲤与黄河鲤、建鲤鱼肉品质的比较及影响肉质的主成分分析

为研究福瑞鲤和黄河鲤、建鲤的肉质差异,选取了体质量相近、相同养殖条件下的3 种鲤鱼,分析其质构特性、肉色、pH值变化及营养成分。结果表明：福瑞鲤剪切力、硬度、胶黏性、咀嚼性指标低于黄河鲤和建鲤,而黏附性高于黄河鲤;水分含量、脂肪含量极显著低于黄河鲤及建鲤（P＜0.01）,灰分含量、蛋白质含量没有显著差异（P＞0.05）,Ser、Cys含量以及必需氨基酸（essential amino acids,EAA）含量较高,Thr含量较黄河鲤、建鲤有很大提升。整体上来说,福瑞鲤鱼肉品质在质构性能和营养价值上要优于黄河鲤和建鲤。而相关性分析表明剪切力、硬度、胶黏性、咀嚼性4 项指标均与粗蛋白、粗脂肪含量两项指标成显著正相关（P＜0.05）;黏附性与粗脂肪含量成负相关（P＜0.05）;从12 项指标中提取出3 个主成分,硬度、剪切力、粗脂肪、粗蛋白为影响肉质性能的最主要因素。     

Effect of storage and separation of milk at udder quarter level on milk composition, proteolysis, and coagulation properties in relation to somatic cell count

Coagulation properties of milk are altered by elevated somatic cell count (SCC), partly due to increased proteolytic and lipolytic activity in the milk and, thereby, degradation of protein and fat during storage. Milk is commonly stored on the farm at cooling conditions for up to 2 d before transport to the dairy for processing. This study evaluated the effects of storage on milk with altered composition due to high SCC and the effects of exclusion of milk from individual udder quarters with high SCC on milk composition, proteolysis, and coagulation properties. Udder-quarter milk and cow-composite milk samples from 13 cows having at least 1 quarter with SCC above 100,000 cells/mL were collected on 1 occasion. In addition, commingled milk from only healthy quarters (<100,000 cells/mL) of each cow was collected, representing a cow sample where milk with elevated SCC was excluded. The milk samples were analyzed for total protein content; protein content in the whey fraction; casein, fat, and lactose contents; SCC; proteolysis; curd yield; coagulation time; and total bacterial count, on the day of sampling and after 2 and 5 d of storage at +4°C. In addition to SCC, duration of storage and total bacterial count had an effect on milk quality. The content of total protein, fat and protein contents in the whey fraction, and curd yield were found to have different storage characteristics depending on the level of SCC at udder-quarter level. The exclusion of milk from udder quarters with elevated SCC decreased the content of total protein and protein content in the whey fraction and increased the content of lactose at cow level. However, the effect of separating milk at udder-quarter level needs to be further studied at bulk tank level to evaluate the effect on overall total milk quality.     

THERMO-RHEOLOGY,QUALITY CHARACTERISTICS,AND MICROSTRUCTURE OF FRANKFURTERS PREPARED WITH SELECTED PLANT AND MILK ADDITIVES1

The purpose of this study was to evaluate substitution of nonmeat proteins for meat protein on the thermo-rheology, quality characteristics, and microstructure of frankfurters. Batters were formulated to contain either 2% sodium caseinate or soy protein isolate, or 3.5% whey protein concentrate or wheat germ flour. The storage modulus (G') of all treatments initially decreased during temperature ramping from 20–50C, then increased rapidly from 60–80C, with all-meat batter exhibiting the highest G' at 80C. Substitution with nonmeat proteins decreased G', shear force, compression force, and red color of meat compared with all-meat frankfurters. Increased protein content, cooking yield, and decreased fat content were obtained with nonmeat protein formulations. Electron micrographs showed that nonmeat proteins were able to bind to the meat protein and fat, forming a protein-fat matrix with less coalescence of fat droplets. Sodium caseinate, soy protein isolate, whey protein concentrate, and wheat germ flour can be used as protein additives in comminuted meat products without adversely affecting their physical characteristics.     

Milk composition,but not cheese properties,are impaired the day after transhumance to alpine pastures

Short-term effects of transhumance to high altitude were investigated in Valdostana bovine milk and Fontina cheeses. The study included samples taken at each milking on days 1, 2 and 5 after transhumance compared with 5 days before; individual cow milk was collected and bulk milk was manufactured to cheese. Somatic cell count and milk fat content increased the day immediately after transhumance. In bulk milk, transhumance effects were less pronounced. Except for sour taste, no clear trend for impaired composition or sensory properties was observed in the cheeses produced on the day after transhumance and ripened for 115 days. Milking time and, with that, manufacturing time influenced milk and cheese quality, leading to higher fat and more melting cheeses in the evening. These results allow better characterisation of the changes during this transition and will help farmers to tackle the difficulties in producing cheese during this period.     

热处理对不同品种青稞全粉结构及理化特性的影响

目的：改善青稞全粉的加工特性。方法：采用过热蒸汽、远红外烘烤和微波烘烤处理对昆仑15号、肚里黄和昆仑20号青稞进行处理,通过扫描电镜、X-射线衍射、热分析及傅里叶变换红外光谱扫描,研究3种热处理方式对青稞全粉结构的影响,并对比处理后基本营养成分、色差、持水力、持油力、休止角、滑角、膨胀力、堆积密度、振实密度和糊化特性的变化。结果：热处理后,青稞全粉的粗蛋白、粗脂肪、粗纤维及灰分含量增加,而总淀粉含量显著减少（P<0.05）;3种热处理均可以改变青稞全粉的组织形态基团结构,但未显著改变青稞全粉的官能团结构;青稞全粉的膨胀力、堆积密度、振实密度、持水性、糊化温度显著增加（P<0.05）,其持油性和白度降低;过热蒸汽处理增加了青稞全粉的黏度值、回生值及崩解值（P<0.05）,而微波烘烤和远红外烘烤的与之相反。结论：热处理能够改善青稞全粉的加工特性,但不同品种之间略有差异,且过热蒸汽处理较适合提高青稞全粉的加工特性。     

How heat stress conditions affect milk yield,composition, and price in Italian Holstein herds

An edited data set of 700 bulk and 46,338 test-day records collected between 2019 and 2021 in 42 Holstein-dominated farms in the Veneto Region (North of Italy) was available for the present study. Information on protein, fat and lactose content, somatic cell count, and somatic cell score was available in bulk milk as well as individual test-day records, whereas urea concentration (mg/dL), differential somatic cell count (%), and milk yield (kg/d) were available for test-day records only. Milk features were merged with meteorological data retrieved from 8 weather stations located maximum 10 km from the farms. The daily and weekly temperature-humidity index (THI; wTHI) and maximum daily (MTHI) and weekly temperature-humidity index were associated with each record to evaluate the effect of heat stress conditions on milk-related traits through linear mixed models. Least squares means were estimated to evaluate the effect of THI and, separately, of MTHI on milk characteristics correcting for conventional systematic factors. Overall, heat stress conditions lowered the quality of both bulk milk and test-day records, with fat and protein content being greatly reduced, and somatic cell score and differential somatic cell count augmented. Milk yield was not affected by either THI or MTHI in this data set, but the effect of elevated THI and MTHI was in general stronger on test-day records than on bulk milk. Farm-level economic losses of reduced milk quality rather than reduced yield as consequence of elevated THI or MTHI was estimated to be between $23.57 and $43.98 per farmer per day, which is of comparable magnitude to losses resulting from reduced production. Furthermore, MTHI was found to be a more accurate indicator of heat stress experienced by a cow, explaining more variability of traits compared with THI. The negative effect of heat stress conditions on quality traits commences at lower THI/MTHI values compared with milk yield. Thus, a progressive farmers' income loss due to climatic changes is already a reality and it is mainly due to deterioration of milk quality rather than quantity in the studied area.     

基于主成分分析的不同小麦品种大曲发酵动态品质评价

为了解小麦品质与大曲质量间的关系,该文测定了5个小麦品种的11个品质性状和大曲发酵中5个阶段的12个质量指标并进行了方差分析、回归分析和主成分分析。结果表明,不同小麦品种间在品质性状和大曲质量指标上存在显著或极显著差异。小麦籽粒容重、脂肪含量、吸水率、湿面筋含量、沉降值与大曲中蛋白增加含量呈极显著正相关;籽粒蛋白质含量与液化力、酯化力呈极显著负相关。多元逐步回归分析表明,大曲糖化力主要受原粮脂肪含量、沉降值和淀粉含量的影响,液化力受容重和淀粉含量的影响,发酵力受千粒重、容重和淀粉含量的影响,而酯化力受容重和淀粉含量的影响。前3个主成分因子的累积方差贡献率达74.57%,采用主成分综合得分筛选出淀粉含量和容重较高的“昌麦34”和“蜀麦691”适宜大曲生产。该研究明确了影响大曲的主要原粮品质性状并建立了新的综合得分评价原粮质量方法,为专用品种的选育和制曲工艺优化提供参考。     

Nutritional potential and functional properties of tempe produced from mixture of different legumes. 1: Chemical composition and nitrogenous constituent

Fermented foods such as Tempe represent a technological alternative for a great variety of legumes and combination of them to improve their nutritional quality and to obtain edible products with palatable sensorial characteristics. The chemical composition, carbohydrate fraction and nitrogenous constituents were investigated for individual different legumes, i.e. faba bean; lupine, chickpea; peas and their mixture before and after fermentation by Rhizopus oligosporus. Tempe had a higher (P < 0.05) protein and fibre content compared with legume mixtures before fermentation, while it had a lower fat, ash and carbohydrate contents. Also, reducing and non‐reducing sugars, stachyose as well as raffinose were reduced after fermentation of legume mixtures. A significant reduction was observed in non‐protein nitrogen and protein nitrogen, while total nitrogen and true protein were increased.     

云岭牛不同部位肉的品质特性分析

为了探索云岭牛不同部位肉品质特性的差异,选用30月龄云岭牛霖肉、臀肉、肩肉、牛腱、黄瓜条和牛腩6个部位肉,对水分、脂肪、蛋白质和胶原蛋白含量、p H值、色差、质构、剪切力、蒸煮损失、解冻损失、凝胶特性及乳化特性进行测定。结果显示:相较于其它品种的牛,云岭牛具有蛋白质含量高,脂肪含量低的特点。肩肉的水分(75.80%)、蛋白质(24.00%)和胶原蛋白含量(13.68%)高,脂肪含量(1.05%)低,凝胶特性、嫩度和保水性均较好,但乳化特性较差;霖肉的蛋白质含量(21.30%)最低,但脂肪(5.13%)和胶原蛋白含量(17.91%)最高;臀肉的凝胶特性和乳化特性较好。结果表明,云岭牛不同部位肉间的品质特性有显著性差异,肩肉适合块状产品开发;霖肉适合烤制产品的开发;臀肉适合肠类产品开发。     

Effects on goat milk quality of the presence of Mycoplasma spp. in herds without symptoms of contagious agalactia

This study was designed to assess the possible effects of mycoplasmas on the quality of milk produced by goat herds in a contagious agalactia (CA) endemic area with absence of classical symptoms. Several factors related to milk quality (percentages of fat, total protein, lactose and total solids, standard plate counts (SPC) and presence of Staphylococcus aureus) were compared in mycoplasma-infected and non-infected herds. To define the CA status of 26 herds on the island of Lanzarote (Spain), where CA is endemic, 570 individual milk samples and 266 bulk tank milk (BTM) samples were microbiologically analysed for the presence of Mycoplasma spp. A herd was considered infected by mycoplasmas when at least a sample (individual or BTM) was positive. BTM samples were also used to determine milk quality parameters. Mycoplasma infection was confirmed in 13 herds. A total of 31, 10 and 11 strains of Mycoplasma mycoides subsp. mycoides LC (MmmLC), Mp. agalactiae and Mp. capricolum subsp. capricolum were isolated. No significant differences were observed between the least square means of the variables fat, total protein, lactose and total solids or SPC recorded for the infected v. non-infected herds. The Staph. aureus status of a herd was also found to be independent of the presence of Mycoplasma spp. Our findings indicate that neither the presence of mycoplasmas in a goat herd with absence of classical symptoms seem to compromise the quality of the BTM.     

冷鲜调理肉三种乳酸菌发酵剂的筛选

为筛选出符合冷鲜调理肉制品发酵的优质乳酸菌发酵剂,对3株乳酸菌的发酵特性进行研究,通过耐盐、耐亚硝酸盐、产粘、产酸能力、蛋白质和脂肪分解能力、菌种间的拮抗作用等试验对其进行优势菌种筛选。结果表明,菌株LLSL、LP、LGG对食盐和亚硝酸盐具有较好的耐受性,能在6%的食盐溶液和150 mg/L亚硝酸盐溶液中存活,能有效产酸,无降解蛋白质和脂肪能力,不产气、不产氨、不产H2S;其中,菌株LLSL、LP不产粘,两者间无拮抗作用,可作为于冷鲜调理肉制品的发酵剂;菌株LGG产粘,影响冷鲜调理肉制品的感官品质和内部组织状态,不适合作为冷鲜调理肉制品的发酵剂。     

Factors associated with herd bulk milk composition and technological traits in the Italian dairy industry

The aim of the present study was to investigate sources of variation of milk composition and technological characteristics routinely collected in field conditions in the Italian dairy industry. A total of 40,896 bulk milk records from 620 herds and 10 regions across Italy were analyzed. Composition traits were fat, protein, and casein percentages, urea content, and somatic cell score; and technological characteristics were rennet coagulation time, curd firming time, curd firmness 30 min after rennet addition to milk, and titratable acidity. Data of herd bulk milks were analyzed using a model that included fixed effects of region, herd nested within region, and season of milk analysis. An average good milk quality was reported in the dairy industry (especially concerning fat, protein, and casein percentages), and moderate to high correlations between composition and technological traits were observed. All factors included in the statistical model were significant in explaining the variation of the studied traits except for region effect in the analysis of casein and somatic cell score. Northeast and central-southern Italian regions showed the best performance for composition and technological features, respectively. Traits varied greatly across regions, which could reflect differences in herd management and strategies. Overall, less suitable milk for dairy processing was observed in summer. Results of the present study suggested that a constant monitoring of technological traits in the dairy industry is necessary to improve production quality at herd level and it may be a way to segregate milk according to its processing characteristics.     

Microstructural transformations in anisotropy and melt-stretch properties of low moisture part skim mozzarella cheese

Mozzarella cheese is primarily consumed in its melted form due to its desirable melt and stretch characteristics when heated. Understanding the relationship between the anisotropic structure and melt-stretch properties is critical for controlling functionality. A novel ex situ sample extraction system was developed to produce melted and stretched mozzarella. New structure analytics were established to reveal transient changes during deformation of mozzarella under dynamic heat-shear conditions. Transformations in anisotropy were examined using various microscopy techniques coupled with image analysis. Coalescence of milk fat aggregates into large droplets upon heating caused loss of anisotropy. However, fat droplets broke down into channels on stretching, comprising agglomerates of smaller droplets, and anisotropy was regained. When stretched further, adhesion between agglomerated fat droplets was broken by forces exerted from the contracted protein fibres. Large fat droplets are necessary as they act as shock absorbers that enable protein fibres to become pliable, allowing greater stretch.     

Fat and protein contents, acidity and somatic cell counts in bulk milk of Holstein cows in the Khorasan Razavi Province, Iran

Relationships between total bulk milk somatic cell score (SCS) and milk fat and protein contents and acidity were investigated in the Khorasan Razavi Province, a region that contributes 6.83% of total milk production in Iran. A total of 1476 samples were analysed. Data were obtained by randomly collecting 123 samples of bulk tank milk from 41 dairy farms during April 2006 to March 2007, every month. Milk was analysed for titratable acidity, protein and fat contents and somatic cell counts (direct microscopic cell count and with Somatos, Russia). Microscopic and Somatos somatic cell counts were comparable. Results showed that the season of raw milk production did not have a significant effect on acidity. Milk fat content increased gradually from spring to winter and there were significant differences ( P <  0.05) between spring and other seasons. Higher levels of milk protein fractions were observed during the autumn and winter than in other seasons. The highest total bulk milk somatic cell counts were observed in July. Total bulk milk SCS had significant effects ( P <  0.05) on acidity and fat and protein contents. Moreover, the level of acidity and fat in milk decreased with increasing SCS. A significant positive relationship was observed between total bulk milk SCS and the protein content of milk. Elevated SCS were associated with lowered milk quality in Holsteins in the Khorasan Razavi Province.     

Towards an optimum mixing protocol for on-farm bulk milk sampling

This paper describes the application of a bottom-sampling technique to dynamically monitor creaming and mixing in bulk milk tanks and determine optimum mixing protocols for milk sampling. Creaming onset in field experiments occurred between 40 and 50 min. Bottom-sampling data determined after 3 h of creaming indicate that the mean mixing time required to ensure a homogenous sample for composition testing is 57 s, and there is a less than 1% probability that an individual tank would require more than 2 min of agitation. Bottom and top-sampling statistics determined after 1 h of creaming indicate mean mixing times of 20 and 34 s, respectively, and predict that individual tank mixing times will exceed 46 and 64 s, respectively, less than 1% of the time. Bacterial cell counts were directly correlated with fat content, but somatic cell counts were independent of fat content. Based on these results, it is recommended that hourly agitation of bulk tanks as currently prescribed in many jurisdictions should be maintained, but the duration of intermittent agitation should be reduced from 5 to 2 min to reduce the impact of agitation on fat globule stability. If hourly agitation is effected during milk storage, agitation time before sampling can be reduced from 5 to 2 min. This will save time for drivers and trucks and reduce the potential impact of agitation on fat globule stability.     

Agglomeration of ethyl esters in model spirit solutions and malt whiskies

Medium- and long-chain ethyl esters were found to have a limited solubility when model spirits and malt distillates were diluted to 230 ml ethanol per litre for sensory analysis. At concentrations above this critical level the concentration of esters in solution remained constant, with the excess esters forming agglomerates. The saturated nature of the solution reduced the volatility of other esters, with a proportion of these compounds being partitioned into the agglomerate. The distribution was dependent on the mole fraction of each ester and its activity coefficient. Dissolution of wood extractives caused a number of changes in the solubility parameters of organic compounds; activity coefficients were increased and both the concentration and activity at which agglomeration occurred were decreased. This resulted in lower solution concentrations with increased concentrations in agglomerates. The reductions in free solution concentration could result in lower headspace concentrations, and thus have a direct effect on the flavour of the matured spirit.     

Water vapour adsorption properties of agglomerated baby food powders

This paper presents an analysis of the physical properties of materials in powder and agglomerate form and their sorption characteristics on the basis of the shape of the water vapour adsorption isotherms and kinetics. The observed changes that led to a decrease in the vapour adsorption ability of the investigated powdered baby foods depended mainly on their milk powder content and to a lesser extent on the structure of the powders. This was related to the process of agglomeration and the type of wetting liquid used in that process. Wet agglomeration of the baby food powders investigated in this study influenced growth of particle size and increased wettability regardless of the type of wetting liquid used and the components of the powders. The agglomerates obtained using 2% lecithin solution or 50% sugar solution as the wetting liquids presented a decrease in their rate of water adsorption compared to the agglomerates obtained using water.