Development of food-grade nanoemulsions and emulsions for delivery of omega-3 fatty acids: opportunities and obstacles in the food industry

Alzheimer’s Disease, Brain Injury, and C.N.S. Nanotherapy in Humans: Sonoporation Augmenting Drug Targeting

Owing to the complexity of neurodegenerative diseases, multiple cellular types need to be targeted simultaneously in order for a given therapy to demonstrate any major effectiveness. Ultrasound-sensitive coated microbubbles (in a targeted nanoemulsion) are available. Versatile small-molecule drug(s) targeting multiple pathways of Alzheimer’s disease pathogenesis are known. By incorporating such drug(s) into the targeted lipid-coated microbubble/nanoparticle-derived (LCM/ND) lipid nanoemulsion type, one obtains a multitasking combination therapeutic for translational medicine. This multitasking therapeutic targets cell-surface scavenger receptors (mainly scavenger receptor class B type I (SR-BI)), making it possible for various Alzheimer’s-related cell types to be simultaneously sought for localized drug treatment in vivo. Besides targeting cell-surface SR-BI, the proposed LCM/ND-nanoemulsion combination therapeutic(s) include a characteristic lipid-coated microbubble (LCM) subpopulation (i.e., a stable LCM suspension); such LCM substantially reduce the acoustic power levels needed for accomplishing temporary noninvasive (transcranial) ultrasound treatment, or sonoporation, if additionally desired for the Alzheimer’s patient.

Is nano safe in foods? Establishing the factors impacting the gastrointestinal fate and toxicity of organic and inorganic food-grade nanoparticles

Nanotechnology offers the food industry a number of new approaches for improving the quality, shelf life, safety, and healthiness of foods. Nevertheless, there is concern from consumers, regulatory agencies, and the food industry about potential adverse effects (toxicity) associated with the application of nanotechnology in foods. In particular, there is concern about the direct incorporation of engineered nanoparticles into foods, such as those used as delivery systems for colors, flavors, preservatives, nutrients, and nutraceuticals, or those used to modify the optical, rheological, or flow properties of foods or food packaging. This review article summarizes the application of both inorganic (silver, iron oxide, titanium dioxide, silicon dioxide, and zinc oxide) and organic (lipid, protein, and carbohydrate) nanoparticles in foods, highlights the most important nanoparticle characteristics that influence their behavior, discusses the importance of food matrix and gastrointestinal tract effects on nanoparticle properties, emphasizes potential toxicity mechanisms of different food-grade nanoparticles, and stresses important areas where research is still needed. The authors note that nanoparticles are already present in many natural and processed foods, and that new kinds of nanoparticles may be utilized as functional ingredients by the food industry in the future. Many of these nanoparticles are unlikely to have adverse affects on human health, but there is evidence that some of them could have harmful effects and that future studies are required.

The New Paradigm for Lipid Oxidation and Insights to Microencapsulation of Omega-3 Fatty Acids

The consumption of omega-3 fatty acids provides a wide range of health benefits. However, the incorporation of these fatty acids in foods is limited because of their high oxidative instability. A new paradigm has emerged to better explain the oxidation mechanism of polyunsaturated fatty acids, which will be discussed here with reference to bulk lipids considered a special case of water in oil microemulsion. This paradigm suggests that lipid oxidation reactions are initiated by heterogeneous catalysis by metal oxides followed by the formation of micelles containing initial hydroperoxides, water, and other amphiphilic compounds. The induction period comes to the end when the formed micelles reach a critical micelle concentration and start to decompose opening the way to intense free radical reactions. Antioxidants and synergists extend the induction period not only by scavenging free radicals but also by stabilizing the micelles. With better understanding of the lipid oxidation mechanism, a tailored choice of antioxidants and synergistic combinations, and efficient encapsulation methods may be optimized to provide stable encapsulates containing highly n-3 polyunsaturated fatty acids. Smart processing and encapsulation technologies utilizing properly stabilized oils as well as optimized packaging parameters aiming to enhance n-3 fatty acid stability by smart selection/design of antioxidants, control of the interfacial physics and chemistry, and elimination of surface oil are needed for this purpose.

Impact of legume protein type and location on lipid oxidation in fish oil-in-water emulsions: Lentil, pea, and faba bean proteins

Emulsion-based delivery systems are being developed to incorporate ω-3 fatty acids into functional foods and beverages. There is interest in formulating these delivery systems from more sustainable and label-friendly ingredients. The aim of this study was therefore to examine the impact of plant-protein emulsifiers on the oxidative stability of 1wt% fish oil-in-water emulsions. Fish oil emulsions stabilized by three types of legume protein (lentil, pea, and faba bean) were produced using a high-pressure microfluidizer. The formation of primary (peroxides) and secondary (TBARS) lipid oxidation products was measured when the emulsions were stored at 37°C under accelerated (+100μM iron sulfate) or non-accelerated (no added iron) conditions for 21 or 33days, respectively. The particle size, charge and microstructure of the emulsions were monitored during storage using light scattering and microscopy to detect changes in physical stability. Emulsions stabilized by whey protein isolate, a commonly used animal-based protein, were utilized as a control. The emulsions formed using whey protein had smaller initial particle sizes, better physical stability, and slightly better stability to lipid oxidation than the ones formed using plant-based proteins. The impact of protein location (adsorbed versus non-adsorbed) on the oxidative stability of the emulsions was also investigated. The presence of non-adsorbed proteins inhibited lipid oxidation, presumably by binding transition metals and reducing their ability to interact with ω-3 fatty acids in the lipid droplets. Overall, these results have important implications for fabricating emulsion-based delivery systems for bioactive lipids, e.g., they indicate that including high levels of non-adsorbed proteins could improve oxidative stability.

Changes in Bioavailability of Omega-3 (DHA) through Alpha-Tocopheryl Phosphate Mixture (TPM) after Oral Administration in Rats

Benefits of Omega-3 Docosahexaenoic acid (DHA) supplements are hindered by their poor solubility and bioavailability. This study investigated the bioavailability of various formulations of Omega-3 and tocopheryl phosphate mixture (TPM), following oral administration in rats, and assessed whether TPM could improve the oral absorption of DHA. The rats were administered with a high (265.7 mg/kg) or low dose (88.6 mg/kg) of DHA. TPM was examined at 1:0.1 w/w (low TPM dose) and 1:0.5 w/w (high TPM dose). Over 24 h, the DHA plasma concentration followed a TPM dose-dependent relationship, reflected in the higher mean Cmax values (78.39 and 91.95 μg/mL) and AUC values (1396.60 and 1560.60) for the low and high TPM, respectively. The biggest difference between the low dose DHA control (LDCont) and TPM formulations was at 4 h after supplementation, where the low and high TPM showed a mean 20% (ns) and 50% (p < 0.05) increase in DHA plasma concentrations versus the control formulation. After correcting for baseline endogenous DHA, the mean plasma DHA at 4 h produced by the LD-HTPM was nearly double (90%) the LDC control (p = 0.057). This study demonstrated that co-administering omega-3 with TPM significantly increases the bioavailability of DHA in the plasma, suggesting potential use for commercially available TPM + DHA fortified products.

Fabrication of Concentrated Fish Oil Emulsions Using Dual-Channel Microfluidization: Impact of Droplet Concentration on Physical Properties and Lipid Oxidation

Chemically unstable lipophilic bioactives, such as polyunsaturated lipids, often have to be encapsulated in emulsion-based delivery systems before they can be incorporated into foods, supplements, and pharmaceuticals. The objective of this study was to develop highly concentrated emulsion-based fish oil delivery systems using natural emulsifiers. Fish oil-in-water emulsions were fabricated using a highly efficient dual-channel high-pressure microfluidizer. The impact of oil concentration on the formation, physical properties, and oxidative stability of fish oil emulsions prepared using two natural emulsifiers (quillaja saponins and rhamnolipids) and one synthetic emulsifier (Tween-80) was examined. The mean droplet size, polydispersity, and apparent viscosity of the fish oil emulsions increased with increasing oil content. However, physically stable emulsions with high fish oil levels (30 or 40 wt %) could be produced using all three emulsifiers, with rhamnolipids giving the smallest droplet size (d < 160 nm). The stability of the emulsions to lipid oxidation increased as the oil content increased. The oxidative stability of the emulsions also depended on the nature of the emulsifier coating the lipid droplets, with the oxidative stability decreasing in the following order: rhamnolipids > saponins ≈ Tween-80. These results suggest that rhamnolipids may be particularly effective at producing emulsions containing high concentrations of ω-3 polyunsaturated fatty acids-rich fish oil.

Oxidative Stability of Granola Bars Enriched with Multilayered Fish Oil Emulsion in the Presence of Novel Brown Seaweed Based Antioxidants

Fucus vesiculosus extracts that have both radical scavenging activity and metal chelating ability in vitro were used as natural antioxidant in granola bars enriched with fish oil emulsion by using primary and secondary emulsion systems stabilized by sodium caseinate alone and sodium caseinate-chitosan. The bars were stored at 20 °C and evaluated over a period of 10 weeks by measuring the development of primary and secondary oxidation products. The samples prepared with secondary emulsion system developed less oxidation products probably due to increased interfacial layer thickness that would act as a barrier to the penetration and diffusion of molecular species that promote oxidation. The positive charge of oil droplets in the secondary emulsion may also inhibit iron-lipid interaction through electrostatic repulsion. Additional protection against lipid oxidation was obtained when fish oil emulsions were added to the granola bars especially in combination with acetone and ethanol extracts of Fucus vesiculosus.

A renaissance of soaps? - How to make clear and stable solutions at neutral pH and room temperature

Soaps are the oldest and perhaps most natural surfactants. However, they lost much of their importance since "technical surfactants", usually based on sulfates or sulfonates, have been developed over the last fifty years. Indeed, soaps are pH- and salt-sensitive and they are irritant, especially to the eyes. In food emulsions, although authorized, they have a bad taste, and long-chain saturated soaps have a high Krafft temperature. We believe that most or perhaps all of these problems can be solved with modern formulation approaches. We start this paper with a short overview of our present knowledge of soaps and soap formulations. Then we focus on the problem of the lacking soap solubility at neutral pH values. For example, it is well known that with the food emulsifier sodium oleate (NaOl), clear and stable aqueous solutions can only be obtained at pH values higher than 10. A decrease in the pH value leads to turbid and unstable solutions. This effect is not compatible with the formulation of aqueous stable and drinkable formulations with neutral or even acidic pH values. However, the pH value/phase behavior of aqueous soap solutions can be altered by the addition of other surfactants. Such a surfactant can be Rebaudioside A (RebA), a steviol glycoside from the plant Stevia rebaudiana which is used as a natural food sweetener. In a recent paper, we showed the influence of RebA on the apKa value of sodium oleate in a beverage microemulsion and on its clearing temperature. In the present paper, we report on the effect of the edible bio-surfactant RebA, on the macroscopic and microscopic phase behavior of simple aqueous sodium oleate solutions at varying pH values. The macroscopic phase behavior is investigated by visual observation and turbidity measurements. The microscopic phase behavior is analyzed by acid-base titration curves, phase-contrast and electron microscopy. It turned out that even at neutral pH, aqueous NaOl/RebA solutions can be completely clear and stable for more than 50days at room temperature. This is for the first time that a long chain soap could be really solubilized in water at neutral pH at room temperature. At last, these findings were applied to prepare stable, highly translucent and drinkable aqueous solutions of omega-3-fatty acids at a pH value of 7.5.

Recent advances in complementary and replacement therapy with nutraceuticals in combating gastrointestinal illnesses

The digestive system provides nourishment to the whole body. Disorders in this system would result in many associated illnesses as the body is deprived of essential nutrients. Gastrointestinal diseases, in particular, gastric ulceration, inflammatory bowel diseases and colorectal cancer have become more prevalent in all population age groups. While this can be attributed to diet and lifestyle changes, the measures to combat these illnesses with conventional drugs is losing popularity owing to the harsh side effects, drug resistance and lack of patient compliance. The focus of this review is to endorse promising nutraceutical dietary components such as phytosterols, polyphenols, anthocyanins and polyunsaturated fatty acids and their synergistic value, in combination with conventional management of key gastrointestinal diseases. As most of these nutraceuticals are labile compounds, the need for protection and delivery using a carrier system is stressed and the methods for targeting to specific parts of the gastrointestinal tract are discussed. A section has also been devoted to perspectives on co-encapsulation methods of drugs and nutraceuticals using different particle systems. Multilayered carrier systems like double layered and core shell particles have been proposed as an exemplary system to co-encapsulate both drugs and nutrients while keeping them segregated.

Enzymes in Fish and Seafood Processing

Enzymes have been used for the production and processing of fish and seafood for several centuries in an empirical manner. In recent decades, a growing trend toward a rational and controlled application of enzymes for such goals has emerged. Underlying such pattern are, among others, the increasingly wider array of enzyme activities and enzyme sources, improved enzyme formulations, and enhanced requirements for cost-effective and environmentally friendly processes. The better use of enzyme action in fish- and seafood-related application has had a significant impact on fish-related industry. Thus, new products have surfaced, product quality has improved, more sustainable processes have been developed, and innovative and reliable analytical techniques have been implemented. Recent development in these fields are presented and discussed, and prospective developments are suggested.

Biopolymer nanovehicles for essential polyunsaturated fatty acids: Structure-functionality relationships

Design of stimuli-sensitive (i.e., smart) nano-sized delivery systems for nutraceuticals, having both a nutritional and pharmaceutical value, is very important for the formulation of novel functional food. Omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) are among the most needed nutraceuticals for the maintenance of good health. It is medically proven that in order to get the best effect on the human health the weight ratio of ω-6/ω-3 PUFAs should be within the range between 1/1 and 5/1. Thus, our work was focused on the molecular design of the delivery systems based on the nano-sized complexes formed between covalent conjugate (sodium caseinate+maltodextrin (a dextrose equivalent=2)) and the combinations of polyunsaturated lipids, which are mutually complementary in the ω-6 and ω-3 PUFAs content: α-linolenic (ALA)+linoleic (LA) acids; liposomes of soy phosphatidylcholine (PC)+ALA; and micelles of soy lysophosphatidylcholine (LPC)+ALA. For such complex particles the high extent (>95%) of encapsulation of these all combinations of lipids by the conjugate was found along with both the high protection of the lipids against oxidation and their high solubility in an aqueous medium. To gain a better insight into such functionality of the complex particles a number of their structural (the weight-averaged molar weight, M_w; the radius of gyration, R_G; the hydrodynamic radius, R_h; the architecture; the volume; the density; the ζ-potential; the microviscosity of both the bilayers of PC liposomes and LPC micelles), and thermodynamic (the osmotic second virial coefficient, A₂, reflecting the nature and intensity of both the complex-complex and complex-solvent pair interactions) parameters were measured by a combination of such basic physico-chemical methods as static and dynamic multiangle laser light scattering, particle electrophoresis, atomic-force microscopy and electron spin resonance spectroscopy.

Phytosterol structured algae oil nanoemulsions and powders: improving antioxidant and flavor properties

Phytosterol structured algae oil nanoemulsions and powders were obtained using a one-pot sonification strategy and followed by spray-drying. β-Sitosterol and γ-oryzanol co-structured microencapsulation is a technique for burying fishy odor and preventing oil oxidation.

pH dependent supramolecular recognition of dapoxyl sodium sulfonate with 2-hydroxypropyl β-cyclodextrin: an application towards food-additive formulation

pH dependent host–guest complexation of dapoxyl sodium sulfonate (DSS), an intramolecular charge transfer dye, with 2-hydroxypropyl beta-cyclodextrin (HP-β-CD) has been investigated.

Effect of Grape Seed Proanthocyanidin-Gelatin Colloidal Complexes on Stability and in Vitro Digestion of Fish Oil Emulsions

The colloidal complexes composed of grape seed proanthocyanidin (GSP) and gelatin (GLT), as natural antioxidants to improve stability and inhibit lipid oxidation in menhaden fish oil emulsions, were evaluated. The interactions between GSP and GLT, and the chemical structures of GSP/GLT self-assembled colloidal complexes, were characterized by isothermal titration calorimetry (ITC), circular dichroism (CD), and Fourier transform infrared spectroscopic (FTIR) studies. Fish oil was emulsified with GLT to obtain an oil-in-water (o/w) emulsion. After formation of the emulsion, GLT was fixed by GSP to obtain the GSP/GLT colloidal complexes stabilized fish oil emulsion. Menhaden oil emulsified by GSP/GLT(0.4 wt %) colloidal complexes yielded an emulsion with smaller particles and higher emulsion stability as compared to its GLT emulsified counterpart. The GSP/GLT colloidal complexes inhibited the lipid oxidation in fish oil emulsions more effectively than free GLT because the emulsified fish oil was surrounded by the antioxidant GSP/GLT colloidal complexes. The digestion rate of the fish oil emulsified with the GSP/GLT colloidal complexes was reduced as compared to that emulsified with free GLT. The extent of free fatty acids released from the GSP/GLT complexes stabilized fish oil emulsions was 63.3% under simulated digestion condition, indicating that the fish oil emulsion was considerably hydrolyzed with lipase.

Physical Stability, Autoxidation, and Photosensitized Oxidation of ω-3 Oils in Nanoemulsions Prepared with Natural and Synthetic Surfactants

The food industry is interested in the utilization of nanoemulsions stabilized by natural emulsifiers, but little research has been conducted to determine the oxidative stability of such emulsions. In this study, two natural (lecithin and quillaja saponin) and two synthetic (Tween 80 and sodium dodecyl sulfate) surfactants were used to fabricate omega-3 nanoemulsion using high pressure homogenization (microfluidization). Initially, all the nanoemulsions contained small (d from 45 to 89 nm) and anionic (ζ-potential from -8 to -65 mV) lipid droplets (pH 7). The effect of pH, ionic strength, and temperature on the physical stability of the nanoemulsion system was examined. Nanoemulsion stabilized with Tween 80, quillaja saponin, or sodium dodecyl sulfate (SDS) exhibited no major changes in particle size or visible creaming in the pH range of 3 to 8. All nanoemulsions were relatively stable to salt addition (0 to 500 mM NaCl, pH 7.0). Nanoemulsions stabilized with SDS and quillaja saponin were stable to heating (30 to 90 °C). The impact of surfactant type on lipid oxidation was determined in the presence and absence of the singlet oxygen photosensitizers, riboflavin, and rose bengal. Riboflavin and rose bengal accelerated lipid oxidation when compare to samples without photosensitizers. Lipid hydroperoxide formation followed the order Tween 80 > SDS > lecithin > quillaja saponin, and propanal formation followed the order lecithin > Tween 80 > SDS > quillaja saponin at 37 °C for autoxidation. The same order of oxidative stability was observed in the presence of photosensitized oxidation promoted by riboflavin. Quillaja saponin consistently produced the most oxidatively stable emulsions, which could be due to its high free radical scavenging capacity.