Ability of conventional and nutritionally-modified whey protein concentrates to stabilize oil-in-water emulsions

Development of curcumin-loaded nanoemulsion stabilized with texturized whey protein concentrate: Characterization, stability and in vitro digestibility

The impacts of pH (2.8, 4.5, and 7.2) and extrusion cooking temperature (60°C, 85°C, and 110°C) on properties of native whey protein concentrate (NWPC) were evaluated, followed by delivering of curcumin through a nanoemulsion system stabilized with extruded WPC (EWPC). Protein solubility, surface hydrophobicity, and emulsion properties such as emulsion activity index (at 1% [w/w] protein concentration), stability index (at 0.5%, 1%, 2%, and 4% [w/w] protein concentration) and creaming index (evaluated at different protein concentrations [0.5%, 1%, 2%, and 4% w/w] and oil levels [20%, 40%, 60%, and 80%]) were improved as a function of the extrusion process. It was found that both covalent and non-covalent interactions contributed to the stabilization of the extrudates. The rheological investigation of the emulsions stabilized with EWPC (at different oil levels [20%, 40%, 60%, and 80%]) revealed high viscosity and shear thinning behavior as well as much higher G' and G″ values. Encapsulation efficiency was increased from 90.8% to 95.7% when NWPC and EWPC were used, respectively. The curcumin-loaded nanoemulsion containing EWPC presented high stability in confronting with ionic strength (NaCl salt with a concentration of 0.1-1 M), pH (3, 5, and 7), thermal treatments (pasteurization at 63°C for 30 min and sterilization at 95°C for 10 min) and storage time (1 month at 4°C and 25°C). In vitro release behavior revealed that samples stabilized with EWPC showed burst release in simulated intestine conditions. However, it was more stable in stomach conditions.

Physicochemical properties of sausage manufactured with carp (Carassius carassius) muscle and pork

The purpose of this study was to compare the physicochemical properties of sausage manufactured with carp (Carassius carassius) muscle and pork. Sausages were prepared using either 100% pork sausage (P10), a mixture of 50% pork and 50% carp muscle (P5C5), or 100% carp muscle (C10). The quality of the sausage emulsion was determined by analyzing approximate composition, pH, instrumental color, cooking yield, water holding capacity (WHC), viscosity, and texture profile analysis (TPA). Moisture content of cooked C10 was significantly higher than that of P10 or P5C5 (p < 0.05); however, protein content of cooked P10 was significantly higher than that of C10 (p < 0.05). The pH of uncooked and cooked C10 was significantly higher than that of P10 and P5C5 (p < 0.05). The cooking yield, WHC, and texture profile analysis of C10 were higher than those of P10 and P5C5 (p < 0.05). In addition, the viscosity of uncooked C10 was higher than that of P10 and P5C5. These results suggest that carp muscle can enhance sausage quality with respect to pH, WHC, cooking yield, viscosity, and TPA.

Stress response and characterization of oil-in-water emulsions stabilized with Kluyveromyces marxianus mannoprotein

This study was intended to investigate physico-chemical, rheological, and emulsifying properties of oil-in-water emulsions prepared from the Kluyveromyces marxianus mannoprotein (KMM). Also, the stress-response function of the KMM emulsions was compared with that of the whey protein concentrate (WPC) emulsions in terms of zeta potential, size, and rheology. The stress experiments were conducted at different pH (3 to 9), ionic composition (0 to 500 mM NaCl), and temperatures (30 to 90 °C). The extracted KMM with a molecular weight of 107.2 kDa had 28.8% proteins and 68.22% carbohydrates. With increasing the KMM concentration to 1.5% (w/w), the zeta potential, droplet size, and apparent viscosity of the emulsions reached -35 mV, ∼1 μ, and ∼9 mPa·s, respectively. After applying pH, ionic composition, and temperature, the KMM emulsions were more stable than the WPC emulsions. In conclusion, KMM can be used as a bioemulsifier and be more effective in stabilizing emulsions than WPC. PRACTICAL APPLICATION: Yeasts are a rich source of natural materials. In this study, we extracted mannoproteins from the yeast cell wall and evaluated their functional properties to be used as an emulsifier in oil-in-water emulsions. The results of this study confirm that the yeast-derived mannoproteins are good at stabilizing these emulsions either in the presence or absence of different environmental conditions.

Gelatin nanoparticles enable water dispersibility and potentialize the antimicrobial activity of Buriti (Mauritia flexuosa) oil

Background

Buriti oil presents numerous health benefits, but due to its lipophilic nature and high oxidation, it is impossible to incorporate it into aqueous food matrices. Thus, the present study evaluated whether powder nanoparticles based on porcine gelatin (OPG) and in combination with sodium alginate (OAG) containing buriti oil obtained by O/W emulsification followed by freeze-drying enabled water dispersibility and preserved or increased the antimicrobial activity of the oil.

Results

OPG presented spherical shape, smooth surface, smaller particle size and polydispersity index [51.0 (6.07) nm and 0.40 (0.05)], and better chemical interaction between the nonpolar amino acids and the hydrophobic oil chain. OPG also presented a higher dispersibility percentage [85.62% (7.82)] than OAG [50.19% (7.24)] (p < 0.05), and significantly increased the antimicrobial activity of the oil by 59, 62, and 43% for Pseudomonas aeruginosa, Klebsiella pneumonia, and Staphylococcus aureus, respectively.

Conclusions

Thus, nanoencapsulation in gelatin is a promising strategy to increase the potential to use buriti oil in foods.

Effect of Seawater on the Technological Properties of Chicken Emulsion Sausage in a Model System

The aim of this study was to compare the effect of seawater to that of conventional salt (NaCl) on the technological properties of chicken emulsion sausages in a model system. Chicken sausages were prepared with seawater at three levels (10%, 15%, and 20%) in iced water (10%, 5%, and 0%, respectively) or with iced water (20%) and salt (1.2%). There was no difference in pH values and fat loss from emulsion stability between the two treatments. In general, with an increase in the amount of seawater, the water holding capacity (cooking yield and water loss), protein solubility (total and myofibrillar protein), and viscosity were increased. The addition of 20% seawater induced greater (p<0.05) water holding capacity, protein solubility, and viscosity compared to the control sample treated with salt, which was accompanied by an increase in the level of myosin heavy chain protein of samples with 10% and 20% seawater. Furthermore, addition of at least 15% seawater increased all of the main textural properties except for cohesiveness along with the moisture of sausage, whereas the fat and protein contents were decreased. Based on these results, the addition of ≥15% seawater to chicken breast sausage can induce equivalent or enhanced technological properties to those induced with salt, including water holding capacity, protein solubility, viscosity, and textural properties.

Influences of Red Pepper Seed Powder on the Physicochemical Properties of a Meat Emulsion Model System

Red pepper seed (RPS) is commonly removed during the production of red pepper powder, which is contains large amounts of dietary fibers and is abundant in nutrients, readily available. In this study, we determined the effects of adding RPS powder on the physicochemical properties of emulsified meat products. Meat emulsion samples were prepared with pork hind leg meat (60%) and back fat (20%), iced water (20%), various additives, and RPS powder at different concentrations [0% (control), 1%, 2%, 3%, and 4%]. For the physicochemical properties, moisture and fat content, pH value, color, emulsion stability, cooking yield, appearance viscosity, and textural properties were examined. Addition of RPS induced significantly higher values in moisture content, pH, cooking yield, and a* values of the meat emulsion samples, regardless of the amount added. However, lower values were obtained for emulsion stability, cooking yield, and viscosity in samples with RPS powder at 3% or 4% among all groups. In general, addition of RPS powder at 1% and 2% led to the greatest values in viscosity of the meat emulsion samples. Higher values (p<0.05) in hardness and springiness were observed in samples with RPS powder at 4% and 3%, respectively. For gumminess, chewiness, and cohesiveness, the addition of RPS powder at 1%, 2%, and 3% induced the highest values (p<0.05) in the meat emulsion samples. These results showed that addition of RPS powder at optimum levels (2%) could be utilized to improve quality properties of emulsified meat products as a non-meat ingredient.

Effects of composition and processing variables on the oxidative stability of protein-based and oil-in-water food emulsions

Because many common foods are emulsions (mayonnaise, coffee creamers, salad dressing, etc.), a better understanding of lipid oxidation mechanisms in these systems is crucial for the formulation, production, and storage of the relevant consumer products. A research body has focused on the microstructural and oxidative stability of protein-stabilized oil-in-water emulsions that are structurally similar to innovative products that have been recently developed by the food industry (e.g., non-dairy creams, vegetable fat spreads, etc.) This review presents recent findings about the factors that determine the development of lipid oxidation in emulsions where proteins constitute the stabilizing interface. Emphasis is given to "endogenous" factors, such as those of compositional (e.g., protein/lipid phases, pH, presence of transition metals) or processing (e.g., temperature, droplet size) nature. Improved knowledge of the conditions that favor the oxidative protection of protein in emulsions can lead to their optimized use as food ingredients and thereby improve the organoleptic and nutritional value of the related products.

Protein-Protein Multilayer Oil-in-Water Emulsions for the Microencapsulation of Flaxseed Oil: Effect of Whey and Fish Gelatin Concentration

The impact of whey protein isolate (WPI) and fish gelatin (FG) deposited sequentially at concentrations of 0.1, 0.5, and 0.75% on the surface of primary oil-in-water emulsions containing 5% flaxseed oil stabilized with either 0.5% fish gelatin or whey protein, respectively, was investigated. The results revealed that the adsorption of WPI/FG or FG/WPI complexes to the emulsion interface led to the formation of oil-in-water (o/w) emulsions with different stabilities and different protection degrees of the flaxseed oil. Deposition of FG on the WPI primary emulsion increased the particle size (from 0.53 to 1.58 μm) and viscosity and decreased electronegativity (from -23.91 to -11.15 mV) of the complexes. Different trends were noted with the deposition of WPI on the FG primary emulsion, resulting in decreasing particle size and increasing electronegativity and viscosity to a lower extent. Due to the superior tension-active property of WPI, the amount of protein load in the WPI primary emulsion as well as in WPI/FG complex was significantly higher than the FG counterparts. A multilayer emulsion made with 0.5% WPI/0.75% FG exhibited the lowest oxidation among all of the multilayered emulsions tested (0.32 ppm of hexanal) after 21 days, likely due to the charge effect of FG that may prevent pro-oxidant metals to interact with the flaxseed oil.

Rheological characterization and stability study of an emulsion made with a dairy by-product enriched with omega-3 fatty acids

This study involved a rheological characterization of a W/O emulsion manufactured on a pilot scale using omega-3 fatty acids as part of the oil phase and butter milk as the emulsifier. Polyunsaturated omega-3 fatty acids are essential to prevent cardiovascular diseases, improve pulmonary function and also form part of the neurological structure. Buttermilk is a by-product of the dairy industry and has a high organic load which possesses surfactant properties and constitutes a good substitute for conventional emulsifiers in the food industry. The microstructural nature of the emulsion was characterized from the viscoelastic parameters and mechanical spectra. The linear viscoelastic range was determined, from which the maximum stress that the emulsion could withstand from the processing conditions without altering its microstructure was established. In addition, the storage stability of the emulsion was studied to instrumentally predict the rheological behaviour before sensory destabilization of the emulsion was observed. At the frequencies used, a significant decrease in dynamic viscoelastic parameters was periodically observed (G 'and G''), showing a structural change during storage. Furthermore, a coalescence phenomenon was observed after 18 months. The formulation with added omega-3 fatty acids and buttermilk provided a basis for obtaining a functional food as well as adding value to an industrial by-product.

Influence of Different Wall Materials on the Microencapsulation of Virgin Coconut Oil by Spray Drying

The main objective of this study was to evaluate the influence of the different wall material combinations on the microencapsulation of virgin coconut oil (VCO) by spray drying. Maltodextrin (MD) and sodium caseinate (SC) were used as the basic wall materials and mixed with gum Arabic (GA), whey protein concentrate (WPC) and gelatin (G). The stability, viscosity and droplet size of the feed emulsions were measured. MD:SC showed the best encapsulation efficiency (80.51%) and oxidative stability while MD:SC:GA presented the lowest encapsulation efficiency (62.93%) but better oxidative stability than the other two combinations. Microcapsules produced were sphere in shape with no apparent fissures and cracks, low moisture content (2.35–2.85%) and high bulk density (0.23–0.29 g/cm3). All the particles showed relatively low peroxide value (0.34–0.82 meq peroxide/kg of oil) and good oxidative stability during storage. MD:SC:GA microencapsulated VCO had the highest antioxidant activity in both of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) (0.22 mmol butylated hydroxyanisole (BHA)/kg of oil) and 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays (1.35 mmol trolox/kg of oil).