Stabilization of myoglobin from different species (produced by cellular agriculture) using food-grade natural and synthetic antioxidants.

Cellular agriculture products, like myoglobin, are increasingly used by the food industry to provide desirable sensory properties to plant-based meat substitutes. This study elucidated the physicochemical properties and redox stability of myoglobin from both natural (equine) and cellular agriculture (bovine, sperm whale, and leopard) sources. The electrical characteristics and water-solubility of the different myoglobin samples were measured from pH 2.5 to 8.5. The isoelectric point of the myoglobin samples depended on the species, being pH 5.5 for equine, pH 4.5 for leopard and bovine, and pH 6.5 for sperm whale. All myoglobin samples had a solubility greater than 80% across the entire pH range studied. All myoglobin solutions appeared red and had two peaks in their UV-visible absorbance spectra after one day, which is consistent with oxymyoglobin formation. Equine myoglobin at pH 8 was selected to study its redox and color stability over time, where the oxymyoglobin oxidative status closely paralleled with the redness of the solutions. The effects of antioxidants (ascorbic acid, caffeic acid, catechin, gallic acid, quercetin, taxifolin, Trolox, and 4-methylcatechol) on the redox and color stability (redness) of the equine myoglobin (pH 8.0) was also studied. Antioxidants with low reduction potential values (ascorbic acid and quercetin) were particularly effective at enhancing the color stability of oxymyoglobin. The computational modeling study showed that amino acids on the myoglobin interacted with antioxidants through hydrogen bonds. The insights obtained may have important implications for the use of cellular agriculture to produce myoglobin for food applications.

Development of food-grade Pickering oil-in-water emulsions: Tailoring functionality using mixtures of cellulose nanocrystals and lauric arginate.

In this study, we investigated the tailoring of food emulsions using interactions between rice bran cellulose nanocrystals (CNCs) and lauric arginate (LAE), which is food-grade cationic surfactant. Complexes of anionic CNCs and cationic LAE (CNCs/LAE) were formed through electrostatic attraction which were characterized using isothermal titration calorimetry (ITC), turbidity, and zeta-potential measurements. The saturation complexes could be formed at ratios of 1:2 (w/w) CNCs-to-LAE. Furthermore, the physical and oxidative stability of oil-in-water emulsions containing lipid droplets coated by CNCs/LAE complexes was determined. Electrostatic complexes formed from 0.02% CNCs and 0.1% LAE produced stable Pickering emulsions that were resistant to droplet coalescence. It was also exhibited that 0.02% CNCs and 0.1% LAE complexes stabilized-emulsions was able to extend the lag phase to 20 days for lipid hydroperoxide and to 14 days for hexanal production. This study shows that food-grade Pickering emulsions with good stability can be produced by CNCs with LAE complexes.

Impact of sodium caseinate, soy lecithin and carrageenan on functionality of oil-in-water emulsions.

Oil-in-water emulsions are the main component of creamers, which are used to cream cold or hot coffee. These emulsions must provide the required lightening power and remain physically stable when introduced into hot acidic coffee solutions. In this study, model oil-in-water emulsions stabilized with mixed emulsifiers of sodium caseinate (0.5%) and soy lecithin (0.5%) were fabricated and their physical properties were examined over a range of pH values (pH 3.5 to 7). These model oil-in-water emulsions had strong lightening power (L* ≈ 87) and good physical stability from pH 5.5 to 7 but were unstable to gravitational separation below pH 5 due to caseinate aggregation around its isoelectric point. Addition of λ-carrageenan (0.05 to 0.175%) to the formulations prior to homogenization effectively improved their pH stability, while addition of κ-carrageenan was ineffective. The significantly higher level of sulfated ester groups in λ-carrageenan may have created a strong electrostatic repulsion between the oil particles, inhibiting their association. Our study suggests that some of the caseinate in coffee creamers can be replaced with plant-based lecithins, but that a plant-based polysaccharide is also needed to ensure their stability when added to hot acidic coffees.

Modulation of caseinate-stabilized model oil-in-water emulsions with soy lecithin.

Demands for plant-based food and beverage products have escalated in recent years. However, many commercial coffee creamers are still being made using dairy derivatives such as sodium caseinate. Therefore, there is a need to investigate the replacement of dairy based proteins with plant-based alternatives. This study was carried out to systematically investigate the properties of model O/W emulsions stabilized by either sodium caseinate (0.25 to 1.5%) or soy lecithin (0.5 to 1.5%). The model emulsions were made of 10% medium chain triglyceride (MCT) oil-in-water emulsions at pH 7. All model O/W emulsions exhibited whitish appearances similar to that of commercial creamers and were effective at lightening black coffee, except those containing the lowest emulsifier concentrations i.e., 0.25% caseinate or 0.5% lecithin. The lightness of the model emulsions depended on the type and level of emulsifier used, with soy lecithin-stabilized emulsions having similar lightening power compare to that stabilized by sodium caseinate. No feathering or free oil were observed in the whitened coffees at the highest emulsifier level used. Mixtures of caseinate and lecithin emulsifiers were also used and model O/W emulsions with similar physical properties to that stabilized by sodium caseinate alone were produced. The mixed emulsifier-stabilized model emulsions had similar lightness when added to coffee than those stabilized by the individual emulsifiers, suggesting similar stabilization mechanisms using these emulsifiers alone or in combination.

Modulation of physical properties of microfluidized whey protein fibrils with chitosan.

There is an increasing market for food and beverage products enriched in proteins and dietary fibers due to their potential health benefits. In this study, the effect of heating (85 °C, 20 min), microfluidization (20,000 psi), and pH (2 to 6.5) on the physicochemical properties of aqueous solutions containing mixtures of whey protein fibrils (7.5%; WPF) and chitosan (0.5%; CN) were examined. Heating of the mixed systems increased their turbidity and apparent viscosity, which was attributed to the formation of protein-rich particles. Interestingly, heating the mixed systems and then applying microfluidization led to phase separation and a lower apparent viscosity, which was attributed to high-pressure disruption of the whey protein fibrils. The pH of the systems significantly influenced their appearance, turbidity, particle size, and apparent viscosity, with high turbidity and viscosity, and large particle size occurring from pH 3.5 to 5.5. These effects were attributed to protein aggregation close to its isoelectric point (pH 5) coupled with electrostatic attraction between anionic groups on the whey protein and cationic groups on the chitosan. The addition of chitosan increased the net isoelectric point from pH 5 for pure whey protein to pH 6 for the mixed system. Overall, this study showed that the appearance and rheological properties of protein-dietary fiber mixtures could be manipulated by heating, microfluidization, and pH adjustment. This information may be useful for designing protein and fiber enriched food and beverage products with desirable physical and sensory properties.

Emulsions as delivery systems for gamma and delta tocotrienols: Formation, properties and simulated gastrointestinal fate.

Tocotrienols have been reported to have stronger bioactivities than tocopherols, and may therefore be suitable as a potent source of vitamin E in functional foods, supplements, and pharmaceuticals. However, their inclusion into new products is hindered by their low water-solubility and oral bioavailability. Oil-in-water emulsions (O/W) could provide an adequate delivery system for these bioactive compounds. Tocotrienols were tested in bulk oil and within O/W conventional emulsions (>10µm) and nanoemulsions (<350nm). The emulsions were prepared with medium chain triglycerides (MCT) as an oil phase (5 to 40% wt) and quillaja saponins as a natural surfactant. The gastrointestinal fate of the emulsion-based delivery systems was investigated using a simulated gastrointestinal tract (GIT). The physical properties of the emulsions (color, apparent viscosity) were affected with increased droplet concentration. The lipid phase composition (emulsion type and particle size) had a pronounced impact on the microstructure of the emulsions in different regions of the GIT. At simulated small intestine conditions, the rate of lipid digestion and tocotrienol bioaccessibility decreased in the following order: nanoemulsions>emulsions>bulk oil. These results suggest that emulsions containing small lipid droplets are particularly suitable for delivering tocotrienols.

Impact of oil droplet concentration on the optical, rheological, and stability characteristics of O/W emulsions stabilized with plant-based surfactant: Potential application as non-dairy creamers.

The development of plant-based foods and beverages is becoming increasingly popular because of growing consumer concerns about perceived ethical, health, and environmental issues. The current study examined the influence of oil droplet concentration on the physicochemical properties of oil-in-water (O/W) emulsions stabilized with a plant-based surfactant. Emulsions were utilized as model creamers, which consisted of medium chain triglycerides (MCT) as the oil phase and quillaja saponin as a plant-based surfactant. The optical, rheological and stability properties of these model creamers were measured at varied oil content from 0 to 15%, at a constant surfactant-to-oil ratio (1:15). The model creamers had an appearance similar to that of commercial non-dairy creamers, and their whiteness increased with increasing droplet concentration due to enhanced light scattering: L* from 77 to 91 for creamer and L* from 5 to 55 for white coffee. The quillaja saponin-coated lipid droplets were stable to aggregation and gravitational separation when added to hot acidic coffee solutions (85°C, pH4.9), which was attributed to strong steric and electrostatic repulsions. The apparent viscosity of the model creamers increased with increasing droplet concentration due to increased frictional losses associated with the presence of the droplets. This study provides valuable information into the impact of oil content on the physicochemical properties of liquid creamers using plant based surfactants, which is important for the formulation of healthier products.

Influence of homogenization on physical properties of model coffee creamers stabilized by quillaja saponin.

There is a growing demand for use of natural ingredients in food manufacturing. This study utilized a natural emulsifier, quillaja saponin (1%) to fabricate non-dairy model creamer emulsions (containing 10% medium chain triglycerides oil). Varying homogenization conditions, ranging from a high-shear mixer to passing through a microfluidizer at 20,000psi, were applied to fabricate emulsions. The effect of particle size on the appearance, tristimulus color coordinates, and electrical characteristics of the model creamers and white coffee drinks were investigated. The average droplet size varied from 0.2 to 16µm. All model creamers had whitish milk-like appearance and the white coffee solutions had light brown color. All systems were physically stable except for the systems with largest oil droplets (1.8 and 16µm), which had creaming. The lightness, L* (whiteness) of the model creamer and the white coffee increased with decreasing oil droplet size, as smaller droplets scatter more light. Decreasing the oil droplet size led to lower zeta potential (from -73 to -54mV) due to lesser negative charge group accumulated on the interfacial layer of the droplets. The oil droplets were also found to be stable to aggregation in hot acidic coffee solutions prepared using model hard water. Overall, this study found that oil droplets stabilized with natural plant-based surfactant have potential for application in liquid coffee creamers and their stability and whitening power were dependent on the droplet size.

Recent Advances in the Utilization of Natural Emulsifiers to Form and Stabilize Emulsions.

Consumer concern about human and environmental health is encouraging food manufacturers to use more natural and sustainable food ingredients. In particular, there is interest in replacing synthetic ingredients with natural ones, and in replacing animal-based ingredients with plant-based ones. This article provides a review of the various types of natural emulsifiers with potential application in the food industry, including phospholipids, biosurfactants, proteins, polysaccharides, and natural colloidal particles. Increased utilization of natural emulsifiers in food products may lead to a healthier and more sustainable food supply. However, more research is needed to identify, isolate, and characterize new sources of commercially viable natural emulsifiers suitable for food use.

Stability improvement of natural food colors: Impact of amino acid and peptide addition on anthocyanin stability in model beverages.

Anthocyanins are prone to chemical degradation and color fading in the presence of vitamin C. The potential of three amino acids (l-phenylalanine, l-tyrosine, l-tryptophan) and a polypeptide (ε-poly-l-lysine) in prolonging the color stability of purple carrot anthocyanins (0.025%) in model beverages (0.05% l-ascorbic acid, citric acid, pH 3.0) stored at elevated temperature (40°C/7 days) was examined. In the absence of amino acids or peptides, anthocyanin degraded at first-order reaction rate. Addition of amino acids or peptide (0.1%) increased the color stability of anthocyanins, with the most significant improvement observed for l-tryptophan. The average half-life of anthocyanin color increased from 2 days to 6 days with l-tryptophan addition. Fluorescence quenching measurements revealed that the l-tryptophan interacted with anthocyanins mainly through hydrogen bonding, although some hydrophobic interaction may also have been involved. Overall, this study suggests that amino acid or peptide addition may prolong the color stability of anthocyanin in beverage products.

Structural design approaches for creating fat droplet and starch granule mimetics.

This article focuses on hydrogel-based strategies for creating reduced calorie foods with desirable physicochemical, sensory, and nutritional properties. Initially, the role of fat droplets and starch granules in foods is discussed, and then different methods for fabricating hydrogel beads are reviewed, including phase separation, antisolvent precipitation, injection, and emulsion template methods. Finally, the potential application of hydrogel beads as fat droplet and starch granule replacements is discussed. There is still a need for large-scale, high-throughout, and economical methods of fabricating hydrogel beads suitable for utilization within the food industry.

Stabilization of natural colors and nutraceuticals: Inhibition of anthocyanin degradation in model beverages using polyphenols.

Anthocyanins are widely used as natural colorants in foods, but they are highly susceptible to chemical degradation during storage leading to color fading. This study examined the potential of natural quillaja saponin and polyphenols (vanillin, epigallocatechin gallate, green tea extract, and protocatechualdehyde) at inhibiting color fading of anthocyanins in model beverages. The purple carrot anthocyanin (0.025%) in model beverages (citric acid, pH 3.0) containing l-ascorbic acid (0.050%) degraded with a first-order reaction rate during storage (40°C/7days in light). The addition of polyphenols (0.2%) delayed color fading, with the most notable improvement observed with green tea extract addition. The half-life for anthocyanin color fading increased from 2.9 to 6.7days with green tea extract. Fluorescence quenching measurements showed that the green tea extract contained components that interacted with anthocyanins probably through hydrophobic interactions. Overall, this study provides valuable information about enhancing the stability of anthocyanins in beverage systems using polyphenols.

Enhancement of colour stability of anthocyanins in model beverages by gum arabic addition.

This study investigated the potential of gum arabic to improve the stability of anthocyanins that are used in commercial beverages as natural colourants. The degradation of purple carrot anthocyanin in model beverage systems (pH 3.0) containing L-ascorbic acid proceeded with a first-order reaction rate during storage (40 °C for 5 days in light). The addition of gum arabic (0.05-5.0%) significantly enhanced the colour stability of anthocyanin, with the most stable systems observed at intermediate levels (1.5%). A further increase in concentration (>1.5%) reduced its efficacy due to a change in the conformation of the gum arabic molecules that hindered their exposure to the anthocyanins. Fluorescence quenching measurements showed that the anthocyanin could have interacted with the glycoprotein fractions of the gum arabic through hydrogen bonding, resulting in enhanced stability. Overall, this study provides valuable information about enhancing the stability of anthocyanins in beverage systems using natural ingredients.

Reduced Fat Food Emulsions: Physicochemical, Sensory, and Biological Aspects.

Fat plays multiple important roles in imparting desirable sensory attributes to emulsion-based food products, such as sauces, dressings, soups, beverages, and desserts. However, there is concern that over consumption of fats leads to increased incidences of chronic diseases, such as obesity, coronary heart disease, and diabetes. Consequently, there is a need to develop reduced fat products with desirable sensory profiles that match those of their full-fat counterparts. The successful design of high quality reduced-fat products requires an understanding of the many roles that fat plays in determining the sensory attributes of food emulsions, and of appropriate strategies to replace some or all of these attributes. This paper reviews our current understanding of the influence of fat on the physicochemical and physiological attributes of food emulsions, and highlights some of the main approaches that can be used to create high quality emulsion-based food products with reduced fat contents.

Enhanced stability of anthocyanin-based color in model beverage systems through whey protein isolate complexation.

Anthocyanins are often used in functional foods and beverages as colorants and nutraceuticals. However, these natural compounds may undergo chemical degradation during storage leading to color fading and loss of bioactivity. In particular, vitamin C (l-ascorbic acid) is known to accelerate anthocyanin degradation. In this study, the influence of various food-grade biopolymers on the physical and chemical stability of model beverages containing anthocyanin (0.025%), ascorbic acid (0 or 0.05%), and calcium salt (0 or 0.01%) was examined under accelerated conditions (40°C for 7days). Four biopolymers (1%) were examined for their potential to inhibit anthocyanin degradation: native whey protein; denatured whey protein; citrus pectin; and beet pectin. The physical stability was determined by measuring changes in absorbance, color, and visual appearance. Solutions containing anthocyanin and calcium salt (0 or 0.01%) were stable throughout storage, while those with added ascorbic acid were the least stable. The addition of biopolymers, particularly heat denatured whey protein, significantly enhanced the stability of the anthocyanin during storage. Fluorescence quenching studies showed that the anthocyanin may have formed complexes with the whey protein through hydrogen bonding that resulted in their enhanced stability in the presence of ascorbic acid. This study provides information that may improve the stability of anthocyanins in food and beverage systems.

Factors Influencing the Freeze-Thaw Stability of Emulsion-Based Foods.

Many of the sauces used in frozen meals are oil-in-water emulsions that consist of fat droplets dispersed within an aqueous medium. This type of emulsion must remain physically and chemically stable throughout processing, freezing, storage, and defrosting conditions. Knowledge of the fundamental physicochemical mechanisms responsible for the stability of emulsion-based sauces is needed to design and fabricate high-quality sauces with the desired sensory attributes. This review provides an overview of the current understanding of the influence of freezing and thawing on the stability of oil-in-water emulsions. In particular, it focuses on the influence of product composition (such as emulsifiers, biopolymers, salts, and cryoprotectants), homogenization conditions, and freezing/thawing conditions on the stability of emulsions. The information contained in this review may be useful for optimizing the design of emulsion-based sauces for utilization in commercial food products.

Reduced calorie emulsion-based foods: Protein microparticles and dietary fiber as fat replacers.

The potential of using microparticulated whey protein (MWP) in combination with either modified starch or locust bean gum (LBG) as fat mimetics to fabricate reduced calorie emulsion-based sauces and dressings was studied. The influence of food matrix composition (protein, polysaccharide, and fat content), ionic strength, and pH on the properties of thermally processed model emulsions (90°C/10min) was investigated. Increasing protein concentration (2.5-7.5%) increased the mean (d3,2) particle diameter due to the formation of large protein aggregates. All MWP-containing systems had a creamy white appearance with high lightness (L*>75). Addition of fat droplets (5%) further increased their lightness (L*>90) due to enhanced light scattering. Addition of starch, LBG, or MWP increased emulsion viscosity due to the increased effective volume fraction of the dispersed phase. Addition of calcium chloride (10mM) and pH adjustment (2-8) caused little change in the physicochemical properties of the mixed systems. Overall, the appearance and rheological properties of the mixed systems were similar to commercial sauces and dressings. This study demonstrates that reduced calorie food emulsions with appearance and consistency similar to those of full-fat versions can be formulated using protein microparticles and polysaccharides.

Immersing the foot in painfully-cold water evokes ipsilateral extracranial vasodilatation.

Temporal pulse amplitude was recorded bilaterally in 56 participants before, during and after three ice-water immersions of the foot. Half of the participants were told that prolonged exposure to freezing temperatures could cause frostbite. Increases in pulse amplitude were greater in the ipsilateral than contralateral temple during and after the three foot-immersions. Although pulse amplitude decreased after threatening instructions and repeated immersion of the foot, the vasodilator response persisted during all three immersions. These findings suggest that nociceptive stimulation of the foot evokes an ipsilateral supra-spinal extracranial vasodilator response, possibly as part of a broader defense response.

Analgesic properties of the novel amino acid, isovaline.

BACKGROUND: Isovaline, a nonproteinogenic alpha-amino acid rarely found in the biosphere, is structurally similar to the inhibitory neurotransmitters glycine and gamma-aminobutyric acid. Because glycine(A) and gamma-aminobutyric acid receptor agonists are antiallodynic, we hypothesized that isovaline produces antinociception in mice. METHODS: All experiments were performed on female CD-1 mice using a blinded, randomized, and controlled design. The effects of RS-isovaline were studied on nociceptive responses to (1) formalin injection into the hindpaw; (2) glutamate injection into the hindpaw; and (3) strychnine injection either into the lumbar intrathecal space or cisterna magna. We determined the effects of IV RS-isovaline (50, 150, or 500 mg/kg; n = 10/dose) or intrathecal RS-, R-, and S-isovaline, glycine, and beta-alanine into the lumbar intrathecal space (5-microL volumes of 60, 125, 250, and 500 mM; n = 9/dose/group) on the response to formalin in the paw. The response to 20 microL intraplantar glutamate (750 mM) was compared with glutamate (750 mM) coadministered with isovaline. We also determined the response to intraplantar strychnine. Lumbar intrathecal (100 microM) or intracisternal (200 microM) injections of strychnine into the lumbar intrathecal space or the cisterna magna were used to induce allodynia as a measure of glycine inhibitory dysfunction. The effects of intrathecal or intracisternal strychnine were compared with isovaline coapplied with the strychnine (n = 8/group). RESULTS: In the formalin paw test, IV isovaline did not change phase I but decreased phase II responses in a dose-dependent manner (50% effective dose = 66 mg/kg, n = 10, P < 0.01). There was no effect on rotarod performance, appearance, or behavior of the mouse, and no respiratory depression. Intrathecal isovaline, glycine, and beta-alanine attenuated phase I and II responses (P < 0.01 for each drug). In contrast to beta-alanine and glycine, isovaline at maximally effective doses did not produce scratching, biting, or agitation. Intrathecal RS- and S-isovaline attenuated phase I (P < 0.05 for each group) and RS-, R-, and S-isovaline attenuated phase II responses (P < 0.05 for each group), with no significant difference between the efficacies of R- and S-enantiomers. Localized strychnine-induced glycine inhibitory dysfunction was greatly reduced by intracisternal (P < 0.01) and intrathecal (P < 0.01) isovaline. Although intraplantar strychnine did not induce peripheral allodynia, high doses of isovaline did not block the peripheral allodynia induced by glutamate. CONCLUSIONS: Isovaline reduced responses in mouse pain models without producing acute toxicity, possibly by enhancing receptor modulation of nociceptive information.

Effects of local tramadol administration on peripheral glutamate-induced nociceptive behaviour in mice.

PURPOSE: The use of peripheral tramadol to block pain has been advocated. However, since its actions in the periphery have not been elucidated fully, we tested the hypothesis that peripheral tramadol blocks peripheral glutamate-induced nociceptive behaviour in mice. METHODS: First, we compared the duration of paw licking after intraplantar (ipl.) glutamate administration, with and without tramadol, using a randomized blinded controlled design. Next, we established the half maximal effective concentrations (EC(50s)) for local tramadol and reference compound lidocaine in the hot water tail-flick latency test and the glutamate-induced paw allodynia assay. RESULTS: Tramadol reduced glutamate-induced paw licking from 33 +/- 12 sec to 4 +/- 4 sec (mean +/- SD; t test, P < 0.05; n = 6 per group). The tramadol and lidocaine EC(50) nerve conduction blocks in the tail did not differ significantly (84 +/- 24 mM vs 69 +/- 5 mM, respectively). Although tramadol reduced glutamate-induced allodynia (EC(50), 46 +/- 13 mM), lidocaine was more potent (EC(50), 13 +/- 5 mM; Dixon's up-and-down method; P < 0.05). Tramadol was 2.5 times as effective at blocking nerve conduction in the tail compared with allodynia in the paw. CONCLUSIONS: Local tramadol administration blocked nociceptive behaviour in mice induced by peripheral glutamate. Compared with lidocaine, the relative potency of tramadol was lower for blocking glutamate-induced allodynia than for sensory nerve conduction blockade, suggesting the activation of a pronociceptive receptor system in the periphery.