INTRODUCTION
Consumers of today’s world are more and more conscious about the very strong relationships between health and nutrition which has fuelled the interest on the development and commercialization of healthier and improved foods with better nutritional value. Functional foods are those containing biologically active components, offering health benefits, and reducing the risk to suffer several common diseases. Functional dairy products such as processed milk, cream, kefir,powdered milk, condensed milk, ricotta, butter, cheese, casein,ice cream, gelato, and yogurt, among several others, represent an important segment and in constant growth. The design of new dairy products fortified with vitamins and minerals such as calcium, magnesium, iron, or zinc, may bring solutions to some of the problems associated with nutritional deficiencies. For example, some fortified yogurts are able to increase the daily ingest of calcium around 50% and are an important source of this mineral to benefit bone health, plus it is also a source for vitamin D-3 (Vander-Heeet al., 2009). There are also important advances on the development of several technologies for the incorporation of relevant nanostructured materials into foods, such as nano- and microencapsulation of preservatives, nutrients, antioxidants, flavors, among other additives.
NANOTECHNOLOGY IN DAIRY FOOD PRODUCTS
Emergent technologies as nanotechnology are using the milk, dairy products and its components to improve nutritional facts and beneficial effects in health by different ways. That is possible because different nutritional components of dairy foodsare able to influence body composition, metabolic homeostasis, and inflammatory state by modulating mitochondrial function and gut microbiota composition (Trincheseet al., 2015). These effects can be influenced at nanoscale, throughout of the socalled nanoeffect, where unique enhanced physical properties (strength), reactivity, or biological interactions occur below100 nm (Riviere, 2012). Nanotechnology is important becauseit is cheap, relatively safe, clean, and the financial rewards are very high. In the food industry significant advancements by nanotechnology are: new functional materials; micro- and nanoscale processing; product development; and designing of methods and instrumentation for food safety and biosecurity. It is not strange that in the next decade nanotechnology will touch every aspect of human being life not only with nanofood or nanomedicine as until now Malnutrition contributes to more than half of the deaths of children under 5 years old in developing nations. Several inexpensive agricultural and food applications of nanotechnology have the potential to decrease malnutrition, and thus infant mortality. Milk fortified with vitamins, minerals, and other functional ingredients via nanoemulsion technology has gained a lot of importance. Carotenoids, in addition to their provitamin-An activity, have recentlybeen implicated in the prevention of, or protection against, serioushuman health disorders such as cancer, heart disease, and cataracts (Imran et al., 2010). There are other reasons for enhanced interest in food nanotechnologies. Obesity could be the payment of the slow-moving lifestyle of human kind for motorization and computerization. For that reason there is a growing demand for foods with low-fat contents, however, that affects also their content of fat soluble vitamins and other nutrients, impacting their nutritional value (Joyeet al., 2014). Nanotechnology can also improve the texture of foods (eg, improving consistency of dairy products such as yogurts and ice cream; Coles and Frewer, 2013). In this sense, nanotechnologies should play a key role in approaching these problems as well. Much of the higherdimensional structure of food is a consequence of nanostructures. The sensory properties of food (including texture, mouth feel, and flavor release) and food structure are important at all dimensional scales. Both of them may have an important effect on release and bioavailability of the nutrient content and the effect of specificcomponents (Boland, 2014).
FORTIFIED DAIRY PRODUCTS
Dairy products enrichment and fortification is very important in order to compensate the loss of natural vitamins and minerals during processing or as a way to improve their nutritional value. For example, the levels of folic acid loss in pasteurized milk, sterilized or UHT treated, are around 5, 30, and 20%, respectively (Ottaway, 2009). Milk, as many other foods, naturally contains nanostructures as some of its proteins (eg, casein) form nanosized clusters that influences mineral equilibrium. However, there is a great potentialto improve the nutritional properties of milk by using nanotechnology. The effect of milk enriched with nanocalcium on the metabolism of ovariectomized rats was reported by Park et al. (2008). They reported that consumption of nano-Ca enriched milk produces an increment in Ca excretion in urine and no differenceon Ca in serum and feces among the groups. In another similar work, Erfanianet al. (2014) reported the effects of fortification and nanosizes reduction on absorption and bioavailability of Ca in ovariectomized and steoporosis rats. The study was performed to optimize the preparation of nanofortified milk powder. It wasfound that the bone strength and bone calcium increased in animals feed with the nanofortified diet in comparison to a normal fortified diet. Vitamin D2 (ergocalciferol) was loaded in tripalmitin solid lipid nanoparticles (SLN), stabilized with Tween-20 (Patel and San Martin-Gonzalez, 2012). The SLNs prepared in this study could find use on the preparation of fortified clear juices loaded with ergocalciferol, as an alternative to milk and margarine as a source of vitamin D.
FUNCTIONAL DAIRY FOODS
Today, there are several functional dairy products in the market and the number is increasing. Some of them are milk-based drinks, yogurts, cheeses, and fermented milk enriched with probiotics and prebiotics. They are commercialized in almost every country in the world (Granatoet al., 2010a). The market of functional dairy
products is a very attractive niche for the industry, in comparison with the worldwide sales for nonfunctional, traditional products such as yogurt or milk.
Functional dairy products able to have therapeutic action are attractive for their health benefits. The use of novel nanoplatforms for oral delivery of anticancer biomacromolecules, using alginate enclosed, chitosan-coated ceramic nanocarriers loaded with anticancer bovine lactoferrin, and a natural milk-based protein may be one day incorporated in foods (even dairy products) in order to overcome the challenges of administrating this type of therapeutic molecule (Mahidharaet al., 2012). Casein, a natural protein found in milk, has been reported to form micelles, which in effect are natural nanocapsules able to deliver nutrients such as Ca or P and proteins. Such casein nanocapsules can be incorporated into dairy products without affecting their sensory properties. Semoet al. (2007) reported that casein micelles can be used as nanocarriers for the entrapment, protection, and delivery of vitamin D in food products. Zimet and Livney (2009)) reported the use of pectin and β-actoglobulin, a major whey protein of cow milk, as naturalnanocarriers for hydrophobic molecules, in particularDecosahexaenoicacid (DHA), is a particular type of omega-3 fatty acid.Stable systems were obtained with good colloidal stability andaverage particle size of 100 nm. The DHA loaded nanocapsulesmay be useful for enrichment of acid drinks. Antioxidants suchas -carotene were incorporated into nanostructured lipid carriers(NLCs) for the preparation of transparent functional beverages(Zhang et al., 2013). Using anhydrous milk fat (AMF) andTween-80 to prepare the NLCs, β-carotene was encapsulated bya phase inversion temperature method, reducing the degradationof β-carotene when compared to a soybean oil-based nanoemulsion.Long chain omega-3 polyunsaturated fatty acids (LC3PUFA)from vegetarian sources, contained into a nanoemulsion dispersedin yogurt, were studied by Lane et al. (2014).
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OTHER APPLICATIONS OF NANO TECHNOLOGY IN MILK AND DAIRY PRODUCTS PROCESSING
Nanomaterials are not only useful as carriers or encapsulating agents for flavors, antioxidants, minerals, vitamins, or other beneficial molecules used to fortify dairy products or milk. They can also participate in the formulation of new generation packing materials as protecting agents against pathogenic bacteria or ascomponents in biosensor devices. For example, a hybrid interface composed of iron oxide nanoparticles and carbon nanotubes have been used for detecting hydrogen peroxide in milk samples in order to assessits quality. The electrochemical biosensor was prepared by dispersing iron oxide nanoparticles in tetrafluoroethyleneperfluoro- 3,6-dioxa-4-methyl-7-octenesulfonic acid copolymer (NafionTM) and then mixing it with multiwalled carbon nanotubes functionalized with a catalase enzyme. The sensor has goodperformance, with a detection limit around 3.7 nM (Thandavanet al., 2015).
POTENTIAL RISKS OF INCORPORATING NANO MATERIAL IN MILK AND MILK PRODUCTS
Nanotechnology has the potential to affect dairy production and processing and can be expected to become an important area. However, there are still concerns on the safety of incorporating nanomaterials into food, as their physical properties and biological interactions may be affected from several factors, including size, dispersibility, or morphology (Cockburn et al., 2012; Popov et al., 2010). Dairy nanofood could include additional nanoparticles as a consequence of indirect contact with nanomaterials during their production, food processing, food packaging, and ingredients as well. For example, during the manufacture and processing of food products, these can be in contact with nanomaterials that have been applied to create no fouling surfaces in food preparation, which prevents clogging of processing machines and reduces the need for both cleaning and machine downtime, lowering production costs (Coles and Frewer, 2013).
In the past years, nanoparticles are included in the list of new ingredients postulated to be implicated in autoimmune diseases. The diet of urbanized parts of the world today is widely different from what it was even two or three decades ago. In the past decades a whole new range of novel food experiences that come from newfood component sources, genetic modifications, chemical ingredients, flavors, preservatives, and application of new technologies as nanotechnology have surged. Unfortunately, the diet has been postulated as a potential environmental risk factor for increased incidences and a prevalence of disorders like autoimmune diseases,although causality has not been proven (Cockburn et al., 2012; Lerner and Matthias, 2015). Milk containing nanoparticles and dairy nanofood could be implicated as well. At nanoscale, physicochemical properties change, which canhave highly unpredictable impacts on humans, other animals, and the environment. The small size, high surface area, and high surface energy of nanosized particles may lead to effects in the barrier intestinal that are not predictable from our knowledge on the behavior of micro- or macrosized (Cockburn et al., 2012; Lerner and Matthias, 2015). Reducing the size at nanoscale is possible to prolong gastrointestinal retention time. Some nanoparticles can cross biological barriers as intestinal barrier, including the blood brain barrier. This phenomenon potentially induce the ability to enter cells and organs and unpredictable biological effects could occur. Unfortunately, little work has been conducted on risk assessment specifically directed to nanomaterialsin food production and it is not known how the human body responds to these chemicals (Cockburn et al., 2012; Coles and Frewer, 2013, Méndez-Rojas et al., 2014).
CONCLUSION
Nanotechnology usage in the food sector, including the dairy food, has been hindered by concerns about the safety of the engineered nanoparticles for human, others animals and environment, as well as ethical, policy, and regulatory issues. At present, there is little regulation regarding nanotechnologies or nanoproducts in the food industry. Risk assessment procedures are in most cases not specific to agrifood or dairy food using nanomaterials, resulting in uncertainty regarding the nature and extent of potential risks. Only a few governmentagencies from different countries have established regulatory frameworks for the use of nanotechnology. Although these regulations are consideredto be extensive to cover agrifood and dairy food applications, it isnecessary to create a specific frame reference at least for generalapplication in the milk and dairy nanofood industry. The ethical right of the consumers to choose whether they wish to be exposed to unknown potential risks, is raised. In addition, the safe use of nanomaterials in food like dairy products requires knowledgein vitro an in vivo of their absorption, distribution, metabolism,excretion, and toxicological profiles. Thus, it is important to develop a risk-assessment framework for the nanomaterials used in the food industry. Additionally, it is necessary that more nanotoxicology studies evaluate the real risk of food products containing some kind of nanoparticle or who has been exposed to nanocomponents used during the primary production, processing,and packaging.
WRITTEN BY
Dr. Pinaki Ranjan Ray
Professor
Faculty of Dairy Technology
West Bengal University of Animal and Fishery Sciences
Email : pinakirray@gmail.com
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