Nanoencapsulation of food ingredients ----

Nanoencapsulation of food ingredients using lipid based delivery systems


Trends in Food Science & Technology
Volume 23, Issue 1, January 2012, Pages 13-27


"Nanoencapsulation allows protection of the sensitive bioactive food ingredients from unfavorable environmental conditions, eradication of incompatibilities, solubilization, or masking of unpleasant taste or odor. This paper reviews the present state of the art of lipid based carriers including nanoemulsions, nanoliposomes, solid lipid nanoparticles (SLNs) and novel generation of encapsulation system namely nanostructure lipid carriers (NLCs) regarding their production method, physicochemical properties, functionalities, stabilization techniques, potential advantages and limitations and delivery mechanisms. In the last section, mathematical models for predication of bioactive release kinetics from lipid based nanocarriers, which can be applied for optimization of encapsulation systems, are presented and some future developments in the area of nanoencapsulation are discussed.  --------------


Nanotechnology is defined as creation, utilization and manipulation of materials, devices or systems in the nanometer scale (smaller than 100 nm). In recent years nanotechnology has found innumerable applications in different food industries ( [Aguilera et al., 2008] , [Fathi and Mohebbi, 2010] , [Neethirajan and Jayas, 2010] , [Rizvi et al., 2010] and [Sanguansri and Augustin, 2006] ). Some potential applications of this technology in nanoencapsulation and delivery of bioactive components have been documented in pharmaceutics, as well as cosmetics and food sciences ( [Farokhzad and Langer, 2009] , [Liu et al., 2008] , [Müller et al., 2007] , [Sagalowicz et al., 2006] , [Shah et al., 2007] and [Shimoni, 2009] ). Delivery system is defined as one in which a bioactive material is entrapped in a carrier to control the rate of bioactive release. Nanocarriers can protect a bioactive component from unfavorable environmental conditions e.g. oxidation and pH and enzymes degradation ( [Fang and Bhandari, 2010] , [Ghosh et al., 2009] and [Zimet and Livney, 2009] ). Nanocarriers provide more surface area and have the potential to enhance solubility, improve bioavailability and ameliorate controlled release and targeting of the encapsulated food ingredients, in comparison to micro-size carriers ( [Mozafari, 2006a] and [Weiss et al., 2009] ).  --------------


Typically, food applicable nanocarrier systems can be carbohydrate, protein or lipid based. Despite of different advantages of carbohydrate and protein based nanocapsules, they do not have potential of fully scale up due to requirement of applying different complicated chemical or heat treatments which cannot be completely controlled. On the other hand, lipid based nanocarriers have possibility of industrial production and bear advantage of more encapsulation efficiency and low toxicity. In this paper we will provide an overview of recent developments in different aspects (e.g. production methods, physicochemical properties, stabilization techniques, release mechanisms, advantages and disadvantages) of four famous lipid based carriers namely nanoemulsions, nanoliposomes, solid lipid nanoparticles (SLNs) and nanostructure lipid carriers (NLCs) (Table 1). In the last section of the paper, mathematical models for predication of bioactive release kinetics of lipid based nanocarriers are presented.  -----------------


Nano delivery systems


Nanoemulsions
Nanoemulsions (also known as miniemulsions or submicron emulsions) are nanoscale droplets of multiphase colloidal dispersions formed by dispersing of one liquid in another immiscible liquid by physical share-induced rupturing ( [Liu et al., 2006] , [Mason et al., 2006] , [Meleson et al., 2004] and [Russel et al., 1989] ). Different size ranges have been reported in the literature for nanoemulsions;  --------------  However, the most appropriate ones based on nanotechnology definition is having size ranges of less than 100 nm and possessing different properties than ordinary emulsions. Nanoemulsions have some interesting physical properties that can be applied to distinguish them from microemulsions. For instance, microemulsions typically show multiple scattering of visible light, and therefore, have a white opaque appearance. In contrast, the droplet sizes in nanoemulsions are much smaller than visible wavelengths; hence most nanoemulsions appear optically transparent ( [McClements and Li, 2010] and [Shakeel and Ramadan, 2010] ). This is a very favorable feature of nanoemulsions for applying them as the nutrient carriers in beverages.  -------------------


Applications and features
Nanoemulsions are good candidate for delivery of poorly water-soluble food ingredients, such as fish oil and lipophilic vitamins, because of their ability to improve bioactive solubilization and potential for enhancing absorption in the gastrointestinal (GI) tract, caused by surfactant induced permeability changes. After ingestion, droplets readily disperse in stomach to small droplet of nanoemulsion, which promotes wide distribution of the encapsulated bioactive throughout the GI condition (Talegaonkar et al., 2010).  ------------------


Liposome
Having a number of benefits, e.g. possibility of large-scale production using natural ingredients and entrapment and release of water-soluble, lipid-soluble, and amphiphilic materials as well as targetability ( [Huwiler et al., 2000] , [Mozafari et al., 2008] and [Thompson et al., 2006] ), liposomes have been widely used in food sector both in research and industry. Notable examples are liposome formulations of antimicrobials ( [Malheiros, Daroit et al., 2010] , [Malheiros, Silveira et al., 2010] , [Taylor et al., 2008] , [Taylor et al., 2005b] , [Taylor et al., 2007] , [Were et al., 2004] and [Were et al., 2003] ), lipophilic vitamins ( [Gonnet et al., 2010] and [Padamwar and Pokharkar, 2006] ), enzymes ( [Dufour et al., 1996] and [Rao et al., 1995] ) and minerals (Arnaud, 1995). Similar to nanoemulsions, liposomes are kinetically stable.  -----------------


Liposomes can be produced using natural ingredients on an industrial scale and have the capability of entrapping materials with different solubilities ( [Mozafari and Khosravi-Darani, 2007] and [Yurdugul and Mozafari, 2004] ). Another important advantage of liposomes (also known as lipid vesicles) is targetability. Lipid vesicles can be tailored to deliver and release their load in the target site inside and outside the body (Mozafari, 2006b).  --------------------


Liposomes are classified based on their number of bilayers and size. According to their bilayer structure, vesicles can be classified as unilamellar vesicles (ULV), multilamellar vesicles (MLV) that consist of one or more concentric lipid bilayer(s) ( [Nagle and Tristram-Nagle, 2000] and [Yung et al., 1985] ). Another type of liposomes is known as multivesicular vesicles (MVV), which includes some small non-concentric vesicles entrapped within a single lipid bilayer. Vesicles can be further categorized by their size, --------------------- Compared to other encapsulation technologies, liposomes can generally provide higher chemical stability and protection to sensitive bioactives such as ascorbic acid and glutathione at high water-activity conditions ( [Kirby, 1993] and [Suntres and Shek, 1996] ).


In spite of having different advantages, nanoliposomes have short release time. To overcome this limitation, chitosan coating can be employed by dropwise addition of chitosan solution to the liposome dispersion (Zaru, Manca, Fadda, & Antimisiaris, 2009). Research in the fields of pharmaceutical and food sciences showed that chitosan coating changed the liposome surface charge and slightly increased its particle size, while the liposome displayed a prolonged in vitro release profile and an enhanced stability ( [Laye et al., 2008] and [Li et al., 2009] ).  ------------------- "


Okay, I believe that is enough for today.  There is a lot to read and think about.  Tomorrow I will give you some information about the other two nanoencapsulation delivery methods being studied (solid lipid nanoparticles and nanostructure lipid carriers), and I will give you the conclusion of the study and a link to the report.  In my opinion this is important stuff.  It's a perfect example of work going on behind the scenes for the most part that will someday produce some very large surprises for the global food industry including most farmers and ranchers who don't have a clue about any of this and really don't want to know about it.


See you tomorrow, and thanks for your time and interest.


tags:
nutrigenomics human nutrition food safety food wars hunger malnutrition poverty genetics nanotechnology robotics kurzweil monsanto dupont pioneer corn genetically modified usda fda eggs beef poultry pork turkey fish shellfish fruits vegetables food borne illness wheat rice oats barley sorghum soybeans alfalfa protein vitamins minerals amino acids fats unidentified growth factors fatty acids genetic engineering climate change food security agribusiness fresh produce desertification  nanoliposomes solid lipid nanoparticles nanoemulsions