Maximizing the value of milk through separation technologies.

Milk is the source of a wide range of proteins that deliver nutrition to the most promising new food products today. Isolated milk proteins are natural, trusted food ingredients with excellent functionality. Separation technologies provide the basis for adding value to milk through the production of proteins that provide the food industry with ingredients to meet specific needs, not possible with milk itself or with other ingredients. The major milk proteins, casein and whey protein, can be isolated by manipulating their compositional and physical properties and then by using various separation technologies to recover the proteins. Additionally, they can be processed in various ways to create a wide range of ingredients with diverse functional characteristics. These ingredients include milk protein concentrate, milk protein isolate, casein, caseinate, whey protein concentrate, whey protein isolate, hydrolysates, and various milk fractions. Within each of these ingredient categories, there is further differentiation according to the functional and nutritional requirements of the finished food. Adding value to milk by expanding from consumer products to ingredients often requires different technologies, marketing structure and distribution channels. The worldwide market for both consumer products and ingredients from milk continues to grow. Technology often precedes market demand. Methods for the commercial production of individual milk components now exist, and in the future as clinical evidence develops, the opportunity for adding value to dairy products as functional foods with health benefits may be achieved. The research and development of today will be the basis of those value-added milk products for tomorrow.     

Milk fats as ingredients

This paper reviews aspects of the use of milk fats as food ingredients from a technico-marketing perspective. Good marketing involves matching the needs of the market place with the strengths of the supplier relative to those needs. A practical approach to using milk fats as ingredients is therefore based on understanding the background science and technology of milk fats, and on appreciating where the attributes of milk fat in its various forms can deliver real benefits to food manufacturers. These considerations have been addressed in three key areas: what are the characteristics of milk fats; how can the properties of milk fats be modified; and what are the typical milk fat ingredients and their applications.     

Physical Properties of Food and Milk Components: Research Needs to Expand Uses

The physical properties of milk components affect the functional properties and quality attributes of foods in which they are used. Hence, knowledge of the basic physical properties of milk components is critical in determining the usefulness of milk components in food formulations and in determining quality attributes and acceptability of foods containing these components. Although much is known about the chemistry of milk components, fundamental data are limited regarding the physical properties that govern functionality and quality. This lack of information may limit potential uses of milk ingredients in the food processing industry.With the increasing formulation and fabrication of food products, the need and demand for reliable functional ingredients will expand. The food processing industry will increasingly place a premium on obtaining functional ingredients with reliable, well-defined physical and functional properties to facilitate automated formulation of food products and to ensure consistent product quality. Additionally, the satisfactory substitution of ingredients or simulation of traditional foods critically depends on knowledge of the physical properties of ingredients and of foods per se. Hence, there is a need for the establishment of a data bank that contains reliable information on the physical and functional properties of milk components and dairy ingredients. Where reliable data are not available, the needed research should be undertaken. In order to be successful in this endeavor, reliable, standardized testing methods need to be developed to measure those physical and functional properties related to quality attributes of foods.     

The use of high-fat and specialized milk powders*

The pressures of consumer demand and competition drive food manufacturers to continually reek new, innovative and functional food ingredients, which assist in product range diversification or a reduction in manufacturing costs or both. The dairy industry has responded to the needs of food manufacturers by supplying a variety of milk based ingredients which offer convenience, functional performance, the unique flavours associated with milk products and cost benefits. These ingredients utilize for the most part the intrinsic properties of the major components of milk in the way they perform. However, the dairy technologist has also sought to modify the properties of milk fat, proteins and the carbohydrate lactose to broaden the capability of milk based ingredients, thus tailoring ingredients for specific uses in particular applications. Ingredients offered by the dairy industry and aspects of their manufacture and use are discussed, with some consideration of the forces which will influence future developments in this field.     

A Simple and Fast Detection Method for Bovine Milk Residues in Foods: A 2‐Site Monoclonal Antibody Immunochromatography Assay

The ingredient declaration on food labels assumes paramount importance in the protection of food‐allergic consumers. China has not implemented Food allergen labeling. A gold immunochromatography assay (GICA) was developed using 2 monoclonal antibodies (mAb) against the milk allergen β‐lactoglobulin in this study. The GICA was specific for pure milk samples with a sensitivity of 0.2 ng/mL. Milk protein traces extracted from 110 food products were detected by this method. The labels of 106 were confirmed by our GICA method: 57 food samples originally labeled as containing milk were positive for β‐lactoglobulin and 49 food samples labeled as not containing milk were negative for β‐lactoglobulin. However, 3 food samples falsely labeled as containing milk were found to contain no β‐lactoglobulin whereas 1 food sample labeled as not containing milk actually contained β‐lactoglobulin. First, these negatives could be because of the addition of a casein fraction. Second, some countries demand that food manufacturers label all ingredients derived from milk as “containing milk” even though the ingredients contain no detectable milk protein by any method. Our GICA method could thus provide a fast and simple method for semiquantitatation of β‐lactoglobulin in foods. Practical Application: The present method provides a fast, simple, semiquantitative method for the determination of milk allergens in foods.     

让您的牛奶动起来——浅谈运动能量乳饮料

<正> 牛奶,对于中国消费者而言,已成为一种融入生活的消费品:早餐时的一杯牛奶,午餐后的一勺酸奶,休闲时的一瓶乳饮料……牛奶正悄然改变着人们的生活方式。与消费习惯的改变同步,牛奶饮料产业(包括鲜奶、UHT 奶、增香奶、乳饮料等)也进入了飞速发展的快车道。据欧洲知名消费品调研公司 Euromonitor 统计,2001年至2006年的6年     

Sheep Milk: Physicochemical Characteristics and Relevance for Functional Food Development

Sheep milk has a high nutritional value and high concentrations of proteins, fats, minerals, and vitamins, as compared to the milks of other domestic species. The physicochemical and nutritional characteristics of sheep milk can be advantageous for the manufacture of products containing prebiotic ingredients and/or probiotic bacteria, which are major categories in the functional food market. Following this technological trend, this review will address the characteristics and advantages of sheep milk as a potentially functional food, as well as the development of sheep milk dairy products containing prebiotics and/or probiotics.     

State of the art of Ready-to-Use Therapeutic Food: A tool for nutraceuticals addition to foodstuff

Therapeutic foodstuff are a challenge for the use of food and functional food ingredients in the therapy of different pathologies. Ready-to-Use Therapeutic Food (RUTF) are a mixture of nutrients designed and primarily addressed to the therapy of the severe acute malnutrition. The main ingredients of the formulation are powdered milk, peanuts butter, vegetal oil, sugar, and a mix of vitamins, salts, and minerals. The potential of this food are the low percentage of free water and the high energy and nutritional density. The high cost of the powdered milk, and the food safety problems connected to the onset of toxigenic moulds on the peanuts butter, slowed down considerably the widespread and homogenous diffusion of this product. This paper presents the state of the art of RUTF, reviews the different proposed recipes, suggests some possible new formulations as an alternative of novel recipes for this promising food.     

Commercial Milk Enzyme‐Linked Immunosorbent Assay (ELISA) Kit Reactivities to Purified Milk Proteins and Milk‐Derived Ingredients

Numerous commercial enzyme‐linked immunosorbent assay (ELISA) kits exist to quantitatively detect bovine milk residues in foods. Milk contains many proteins that can serve as ELISA targets including caseins (α‐, β‐, or κ‐casein) and whey proteins (α‐lactalbumin or β‐lactoglobulin). Nine commercially‐available milk ELISA kits were selected to compare the specificity and sensitivity with 5 purified milk proteins and 3 milk‐derived ingredients. All of the milk kits were capable of quantifying nonfat dry milk (NFDM), but did not necessarily detect all individual protein fractions. While milk‐derived ingredients were detected by the kits, their quantitation may be inaccurate due to the use of different calibrators, reference materials, and antibodies in kit development. The establishment of a standard reference material for the calibration of milk ELISA kits is increasingly important. The appropriate selection and understanding of milk ELISA kits for food analysis is critical to accurate quantification of milk residues and informed risk management decisions.     

功能性食品添加剂在液态奶中的应用和发展趋势

<正> 液态奶制品近年来在国内的发展态势迅猛,产量逐年大幅度攀升,成为中国乳制品市场的主导产品,并以不断增加的产品品种和产量占得更多的份额。而产品的质量和口味是企业取得竞争优势的重要法宝,而功能性食品添加剂对改善液态奶的产品质量,提高感官品质起着重要的作用。     

Food matrix standards for the quantification of allergenic food ingredients using real-time PCR

For the quantification of food allergens by real-time polymerase chain reaction (PCR), food matrix standards with defined levels of spiked allergenic food ingredients can be used. The production and homogeneity testing of selected materials as sausages, cookies and sauce hollandaise powder is described. Except for egg and milk, all relevant allergenic ingredients were spiked to each material. Allergens were spiked and quantified as food ingredients, for example, peanut or lupine flour, at levels of 5–400 mg/kg. Material with sufficient homogeneity could be produced even at low levels of 5–10 mg of the allergenic ingredient per kilogram. The effect of the food matrix on allergen quantification was checked. The bias caused by this effect was in an acceptable range for the tested materials. The materials produced within this study were used as samples and for calibration in inter-laboratory validation studies for the quantification of allergenic food ingredients by real-time PCR. The results of this study are a contribution how to produce such reference materials for allergen analysis in the near future. Before threshold or action values of allergens in food are set, the availability of reference materials is essential.     

Innovative Uses of Milk Protein Concentrates in Product Development

Milk protein concentrates (MPCs) are complete dairy proteins (containing both caseins and whey proteins) that are available in protein concentrations ranging from 42% to 85%. As the protein content of MPCs increases, the lactose levels decrease. MPCs are produced by ultrafiltration or by blending different dairy ingredients. Although ultrafiltration is the preferred method for producing MPCs, they also can be produced by precipitating the proteins out of milk or by dry‐blending the milk proteins with other milk components. MPCs are used for their nutritional and functional properties. For example, MPC is high in protein content and averages approximately 365 kcal/100 g. Higher‐protein MPCs provide protein enhancement and a clean dairy flavor without adding significant amounts of lactose to food and beverage formulations. MPCs also contribute valuable minerals, such as calcium, magnesium, and phosphorus, to formulations, which may reduce the need for additional sources of these minerals. MPCs are multifunctional ingredients and provide benefits, such as water binding, gelling, foaming, emulsification, and heat stability. This article will review the development of MPCs and milk protein isolates including their composition, production, development, functional benefits, and ongoing research. The nutritional and functional attributes of MPCs are discussed in some detail in relation to their application as ingredients in major food categories.     

The science of plant-based foods: Constructing next-generation meat,fish, milk,and egg analogs

Consumers are increasingly demanding foods that are more ethical, sustainable and nutritious to improve the health of themselves and the planet. The food industry is currently undergoing a revolution, as both small and large companies pivot toward the creation of a new generation of plant-based products to meet this consumer demand. In particular, there is an emphasis on the production of plant-based foods that mimic those that omnivores are familiar with, such as meat, fish, egg, milk, and their products. The main challenge in this area is to simulate the desirable appearance, texture, flavor, mouthfeel, and functionality of these products using ingredients that are isolated entirely from botanical sources, such as proteins, carbohydrates, and lipids. The molecular, chemical, and physical properties of plant-derived ingredients are usually very different from those of animal-derived ones. It is therefore critical to understand the fundamental properties of plant-derived ingredients and how they can be assembled into structures resembling those found in animal products. This review article provides an overview of the current status of the scientific understanding of plant-based foods and highlights areas where further research is required. In particular, it focuses on the chemical, physical, and functional properties of plant-derived ingredients; the processing operations that can be used to convert these ingredients into food products; and, the science behind the formulation of vegan meat, fish, eggs, and milk alternatives.     

植物蛋白与乳蛋白在肉制品加工中的应用

植物蛋白和乳蛋白由于具有较高的营养价值和优良的功能特性,作为食品配料被广泛应用于肉类工业。本文简要介绍了肉制品加工中使用的植物蛋白与乳蛋白、植物蛋白与乳蛋白在肉制品加工中应用的主要功能特性及植物蛋白与乳蛋白在肉制品加工中的作用。     

Structures and functionalities of milk proteins∗

During the last decade, marked progress has been made in the study of the fine details of the structures of milk proteins such as caseins, β‐lactoglobulin, α‐lactalbumin, and lactotransferrin. Many of the functional properties of the individual milk proteins, as well as the milk protein products, may be described at the molecular level. This article is an attempt to thoroughly review the three‐dimensional structures of major milk proteins, and to correlate them with the functional aspects of these proteins as food ingredients.     

DHA藻油的生理功能及在食品中复配协同应用的研究进展

二十二碳六烯酸（docosahexaenoic,DHA）是一种人体必需的多不饱和脂肪酸,属于omega-3家族,主要来源为鱼油和藻油。与鱼油相比,藻油因为含有较高的DHA纯度和更高的安全性而备受青睐,因此被大量应用在食品和保健品中,与食品中的成分相互影响、协同增效。本文综述了DHA藻油的生理功能,包括促进大脑和眼部神经发育、增强免疫力、抗氧化和抗癌等。总结了DHA藻油在牛奶、酸奶、奶粉中的应用,探讨了它与益生菌、益生元、磷脂酰丝氨酸、卵磷脂等食品成分相互作用的效果与机制,为食品、保健品行业更广泛、深入地使用DHA藻油提供理论依据。     

Why semicarbazide (SEM) is not an appropriate marker for the usage of nitrofurazone on agricultural animals

A comprehensive global database on semicarbazide (SEM) in foodstuffs and food ingredients is presented, with over 4000 data collected in foods such as seafood (crustaceans, fish powders), meat (beef, chicken powders), dairy products (e.g. raw milk, milk powders, whey, sweet buttermilk powder, caseinate, yoghurt, cheese), honey and other ingredients. The results provide evidence that the presence of SEM in certain dairy ingredients (whey, milk protein concentrates) is a by-product of chemical reactions taking place during the manufacturing process. Of the dairy ingredients tested (c. 2000 samples), 5.3% showed traces of SEM > 0.5 µg/kg. The highest incidence of SEM-positive samples in the dairy category were whey (powders, liquid) and milk protein concentrates (35% positive), with up to 13 µg/kg measured in a whey powder. Sweet buttermilk powder and caseinate followed, with 27% and 9.3% positives, respectively. SEM was not detected in raw milk, or in yoghurt or cheese. Of the crustacean products (shrimp and prawn powders) tested, 44% were positive for SEM, the highest value measured at 284 µg/kg. Fish powders revealed an unexpectedly high incidence of positive samples (25%); in this case, fraudulent addition of shellfish shells or carry-over during processing cannot be excluded. Overall, the data provide new insights into the occurrence of SEM (for dairy products and fish powders), substantially strengthening the arguments that SEM in certain food categories is not a conclusive marker of the use of the illegal antibiotic nitrofurazone.     

Effect of proteolysis during Cheddar cheese aging on the detection of milk protein residues by ELISA

Cow milk is a common allergenic food, and cow milk-derived cheese retains an appreciable level of allergenicity. The specific and sensitive detection of milk protein residues in foods is needed to protect milk-allergic consumers from exposure to undeclared milk protein residues contained in foods made with milk or milk-derived ingredients or made on shared equipment or in shared facilities with milk or milk-derived ingredients. However, during cheese ripening, milk proteins are degraded by chymosin and milk-derived and bacterial proteases. Commercial allergen-detection methods are not validated for the detection of residues in fermented or hydrolyzed products. The objective of this research was to evaluate commercially available milk ELISA kits for their capability to detect milk protein residues in aged Cheddar cheese. Cheddar cheese was manufactured at a local dairy plant and was aged at 5°C for 24 mo, with samples removed at various time points throughout aging. Milk protein residues and protein profiles were measured using 4 commercial milk ELISA kits and sodium dodecyl sulfate-PAGE. The ELISA data revealed a 90% loss of milk protein residue signal between the youngest and oldest Cheddar cheese samples (0.5 and 24 mo, respectively). Sodium dodecyl sulfate-PAGE analysis showed protein degradation throughout aging, with the highest level of proteolysis observed at 24 mo. Results suggest that current commercial milk ELISA methods can detect milk protein residues in young Cheddar cheese, but the detection signal dramatically decreases during aging. The 4 evaluated ELISA kits were not capable of detecting trace levels of milk protein residues in aged cheese. Reliable detection of allergen residues in fermented food products is critical for upholding allergen-control programs, maintaining product safety, and protecting allergic consumers. Furthermore, this research suggests a novel use of ELISA kits to monitor protein degradation as an indication of cheese ripening.     

The Distribution of Fat in Dried Dairy Particles Determines Flavor Release and Flavor Stability

Dried dairy ingredients are utilized in various food and beverage applications for their nutritional, functional, and sensory properties. Dried dairy ingredients include milk powders of varying fat content and heat treatment and buttermilk powder, along with both milk and whey proteins of varying protein contents. The flavor of these ingredients is the most important characteristic that determines consumer acceptance of the ingredient applications. Lipid oxidation is the main mechanism for off‐flavor development in dried dairy ingredients. The effects of various unit operations on the flavor of dried dairy ingredients have been investigated. Recent research documented that increased surface free fat in spray dried WPC80 was associated with increased lipid oxidation and off‐flavors. Surface free fat in spray‐dried products is fat on the surface of the powder that is not emulsified. The most common emulsifiers present in dried dairy ingredients are proteins and phospholipids. Currently, only an association between surface free fat and lipid oxidation has been presented. The link between surface free fat in dried dairy ingredients and flavor and flavor stability has not been investigated. In this review, some hypotheses for the role of surface free fat on the flavor of dried dairy ingredients are presented along with proposed mechanisms.     

Enterobacter sakazakii in food and beverages (other than infant formula and milk powder)

The ubiqitous microorganism Enterobacter sakazakii is a rare contaminant of infant formula and may cause severe systemic infection in neonates. So far, other food is not known to cause E. sakazakii-infections. The scarce information about the ecology of E. sakazakii and the uncertainty concerning the source of infection in children and adults warrant a summary of the current knowledge about the presence of this opportunistic microorganism in food other than infant formula. This review systematizes publications on the presence of E. sakazakii in food and beverages until June 2006. Food other than infant formula has been rarely investigated for the presence of E. sakazakii. Nevertheless, this microorganism could be isolated from a wide spectrum of food and food ingredients. E. sakazakii was isolated from plant food and food ingredients like cereal, fruit and vegetables, legume products, herbs and spices as well as from animal food sources like milk, meat and fish and products made from these foods. The spectrum of E. sakazakii-contaminated food covers both raw and processed food. The kind of processing of E. sakazakii-contaminated food was not restricted to dry products. Fresh, frozen, ready-to-eat, fermented and cooked food products as well as beverages and water suitable for the preparation of food, were found to be contaminated by E. sakazakii. Although E. sakazakii-contaminated food do not have general public health significance, measures for prevention should consider the presence of E. sakazakii in food, food ingredients, their processing and preparation as possible source of contamination, colonization or infection.