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Food Biophysics
Journal Prestige (SJR): 0.74  Citation Impact (citeScore): 2 Number of Followers: 2  Hybrid journal (It can contain Open Access articles)ISSN (Print) 1557-1866 - ISSN (Online) 1557-1858 Published by Springer-Verlag  [2469 journals]
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- Impact of Saturation of Fatty Acids of Phosphatidylcholine and Oil Phase
on Properties of β-Lactoglobulin at the Oil/Water Interface-
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Abstract: Oil in water emulsions are commonly stabilized by emulsifying constituents like proteins and/or low molecular weight emulsifiers. The emulsifying constituents can compete or coexist at the interface. Interfacial properties thus depend on molecular structure of the emulsifying constituents and the oil phase and the resulting molecular interactions. The present study systematically analyzed the impact of fatty acid saturation of triacylglycerides and phosphatidylcholine on the interfacial properties of a β-lactoglobulin-stabilized interface. The long-term adsorption behaviour and the viscoelasticity of β-lactoglobulin-films were analyzed with or without addition of phosphatidylcholine via drop tensiometry and dilatational rheology. Results from the present study showed that increasing similarity in fatty acid saturation and thus interaction of phosphatidylcholine and oil phase increased the interfacial tension for the phosphatidylcholine alone or in combination with β-lactoglobulin. The characteristics and stability of interfacial films with β-lactoglobulin-phosphatidylcholine are further affected by interfacial adsorption during changes in interfacial area and crystallization events of low molecular weight emulsifiers. This knowledge gives guidance for improving physical stability of protein-based emulsions in foods and related areas. Graphic abstract
PubDate: 2022-06-01
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- Investigating Morphology of Food Systems and Water-biopolymer Interactions
in Food Using 1H NMR Relaxometry-
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Abstract: Abstract NMR relaxometry can be used to measure proton relaxation in water, fat, and biopolymers. Proton relaxation can be analyzed using two independent longitudinal and transverse relaxations, the rates of which are expressed by T1 and T2 relaxation times, respectively. Relaxation time is correlated with the mobility of protons, which reflects the surrounding microenvironments and solid-liquid states. Therefore, NMR relaxometry can provide a tool that employs water and fat molecules as probes to investigate the morphology, water-biopolymers interactions, and solid-liquid phase transition of food products. Based on a diffusive and chemical exchange model, multiexponential relaxation components observed in foods have been explained by morphology and water-biopolymer interactions. This review introduces the principles of NMR relaxometry and relaxation time measurements, followed by current theories of multiexponential relaxation in foods. Multiexponential proton distributions are then discussed, based on morphology, water diffusion, and water-biopolymers in representative food systems.
PubDate: 2022-06-01
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- Incidental Nanoparticles in Black Tea Infusion: Carriers of Bioactives
Fortifying Protection on Intestinal Mucosal Cells Against Oxidative
Stresses-
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Abstract: Abstract The health benefits of black tea have been well recognized worldwide. However, the low bioavailability of major bioactive compounds from tea has compromised the molecule-based mechanism of tea’s function. Knowing tea infusion is rich in polymers and colloidal particles, a hypothesis is proposed here that tea bioactives may have self-assembled into colloidal nanoparticles to interact with mucosal cells in alimentary tract, regulating intestinal barrier function and mucosal immunity. The present study of colloidal nanoparticles (NPs) from a Chinese black tea infusion supports this new perspective. The NPs with hydrodynamic diameter of 180 nm and ζ-potential of -33.4 mV were efficiently isolated with size-exclusive chromatography. The NPs are mainly composed of protein and polysaccharides, together with caffeine, gallic acid and catechins. A hypothetic structure of the NPs was proposed according to FTIR spectra analysis and cryo-TEM images, in which the small molecular components were carried by the proteins-polysaccharides hybrid core. Possibly owing to enrichment of bioactives on the interfacial space of particles, the antioxidant activity of NPs was more potent than the tea bioactive compounds in free form at the same concentrations. The NPs elevated both extracellular and intracellular antioxidant activities, scavenging reactive oxygen species in human intestinal epithelial cells and murine peritoneal macrophages challenged by AAPH-derived peroxyl radicals, restoring macrophages’ cell membrane potential and mitochondrial oxygen respiration. It showcases the cell protective capacity of incidental nanoparticles in food, enlightens the future of employing food nanoparticles to boost the mucosal barrier function and immunity, ameliorating inflammations in alimentary tract.
PubDate: 2022-06-01
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- Investigating the Molecular Effects of Curcumin by Using Model Membranes
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Abstract: Abstract Curcumin (diferuloylmethane, CUR), is an potential agent that is extracted from the rootstalk of the Curcuma longa (turmeric) plant and has anti-cancer effects as well as antibiotic, antiviral, antifungal and anti-inflammatory properties. Within the scope of this study, it was aimed to examine the molecular interactions of curcumin with model membranes. The model membranes were prepared in the form of multilamellar vesicles (MLVs) by using cholesterol (CHOL), one of the most important components of biological membranes, and dipalmitoyl phosphatidylcholine (DPPC), one of the most frequently observed phospholipids in biological membranes. The effects of curcumin were investigated on lipid bilayers, which were classified as binary (DPPC + CUR) and ternary (DPPC/CHOL + CUR) systems. The effects of curcumin at different concentrations on the model membranes were examined with the differential scanning calorimetry (DSC) and Fourier transformation infrared (FTIR) spectroscopy techniques. The results obtained from the DSC indicated that the use of the agent and the cholesterol with the agent caused the pretransition temperature to disappear both in the binary and ternary systems. While the presence of curcumin at different concentrations caused a decrease in the main phase transition temperature (Tm) and enthalpy (ΔH) values in both systems, it caused an increase in the width of the transition at half peak height (ΔT1/2). The results obtained from the FTIR analyses indicated that while the existence of curcumin and cholesterol with curcumin decreased the order of model membranes in the gel phase, it increased it in the liquid crystalline phase and it also caused an increase in fluidity in both phases. When the C = O stretching bands were examined, an increase in the wavenumbers was observed in both phases of both systems. According to the results of the analysis of the \({\mathrm{PO}}_{2}^{-}\) stretching bands, there was an increase in the wavenumbers of samples with 24% mol curcumin in the binary system in both phases and a decrease in the wavenumbers of samples of other concentrations. In the ternary system, an increase was observed in wavenumbers in all concentrations in both phases. When all of the calorimetric and spectroscopic results were evaluated, it was determined that curcumin interacts with the lipids as a whole.
PubDate: 2022-06-01
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- Sub3 Inhibits Mycelia Growth and Aflatoxin Production of Aspergillus
Flavus-
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Abstract: Abstract Sub3, a short cationic antimicrobial peptide, exhibits potent antifungal activity against Aspergillus flavus. A model of the mechanisms through which Sub3 affects A. flavus spores has been proposed in our previous work. However, the antifungal effects of Sub3 on mycelial growth and aflatoxin production of A. flavus remain unclear. In our study, we found that Sub3 strongly inhibited mycelial growth, sporulation, and sclerotia formation on potato dextrose agar and yeast extract peptone dextrose medium at 400 μg/mL. Furthermore, production of aflatoxin B1 was reduced by 18.93% and 98.92% after treatment with 200 and 400 μg/mL Sub3, respectively. Shrivelled hyphae were observed by scanning electron microscopy following 12 h Sub3 treatment. Additionally, Sub3 destroyed membrane integrity, decreased mitochondrial membrane potential, and caused excessive nuclear condensation, as illustrated by propidium iodide, 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethylbenzimidazolocarbocyanine iodide and 4′,6-diamidino-2-phenylindole staining. After treatment with 100 and 150 μg/mL Sub3, intracellular malate dehydrogenase activity decreased by 46.13% and 56.58%, and succinate dehydrogenase activity decreased by 35.35% and 81.25%, respectively. Meanwhile, the pathogenicity assay demonstrated that Sub3 possessed potent antifungal activity in reducing A. flavus infection in maize seeds, as it could reduce conidia and aflatoxin production. Therefore, our findings indicate that Sub3 has significant potential as an eco-friendly antifungal agent against A. flavus in the food.
PubDate: 2022-06-01
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- Effects of Pine Needle Essential Oil Combined with Chitosan Shellac on
Physical and Antibacterial Properties of Emulsions for Egg Preservation-
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Abstract: In this study, the structural changes of chitosan- (C) shellac (S) bio-based emulsions induced by the incorporation of pine needle essential oil (PNEO) were investigated, in addition to, the effect of enhancements in physical, functional, and antibacterial properties of coatings on egg preservation. The ability of emulsion-based coatings to combine the structural strength of the hydrophilic phase with the hydrophobicity of the lipid was interpreted. Rheological analysis indicated that an appropriate amount of PNEO endowed the coating-forming emulsions (CFE) with proper viscosity and gel properties. The C-S-PNEO3 combined with 0.6 g PNEO had the optimal application and storage stability reflected by the lowest particle size and potential. SEM observed a flatter surface morphology of the coatings with the addition of 0.4 and 0.6 g PNEO, while XRD and FTIR also revealed that PNEO improved the biocompatibility by reducing the crystallinity of the coating, while hydrogen bonds were formed between chitosan, shellac. Furthermore, the physical properties of the coating, such as water vapor permeability (WVP), gas permeability, light transmittance, and color parameters were affected by the PNEO. The results showed that the uniform texture, excellent water vapor, oxygen, ultraviolet (UV) barrier performance, and bacteriostatic effect of the C-S-PNEO3 coating contributed to egg packaging. Highlights PNEO incorporation affected the properties of emulsions as well as the properties of coatings. Coating-forming emulsions have good structural properties and storage stability. C-S-PNEO3 was endowed with strong barrier properties and antibacterial activity for eggs preservation. PNEO had good biocompatibility with C and S determined by XRD. Prepared bio-based emulsion coatings were an emerging egg packaging material.
PubDate: 2022-06-01
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- Structure Design for Improving the Characteristic Attributes of Extruded
Plant-Based Meat Analogues-
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Abstract: Abstract Meat is a major source of high protein food for human beings, but livestock animals inevitably have negative consequences for environmental change. Plant proteins exhibit a promising potential to replace meat by developing plant-based meat analogues. The main challenge nowadays is how to endow the meat analogues with the similar attributes of real animal meats. The present work focuses on the structure design by improvement of the formulations and optimization of processing conditions using high moisture extrusion technology to create plant-based meat alternatives, and aims to clarify the relationship between the structure and formulation/processing. The major ingredients including proteins, polysaccharides, and their blends for the preparation of meat analogues are summarized since they are major structural components for the product identity and product differentiation, and have vital roles in fibrous structure formation of meat analogues. Extrusion variables, particularly the barrel temperature, the cooling die design and the moisture content of the feed are discussed as the quality of meat analogues could be tailored by extruder design and controlling.
PubDate: 2022-06-01
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- Quantifying Phase Behaviour in Model Food Composites Using 3D Confocal
Laser Scanning Microscopy-
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Abstract: There is an increasing demand for the design of complex bio-composites with customized structural characteristics for use in processed food products. Phase behaviour of these mixtures determines textural properties, encouraging the pursue of a rapid technique that can accurately quantify it. The present work tests the efficacy of confocal laser scanning microscopy (CLSM) coupled with image analysis software (Imaris), for the quantification of phase behaviour in complex tertiary systems. In doing so, it develops phase separated gels of agarose and gelatin supporting inclusions of canola oil. The polysaccharide was replaced with whey protein isolate (WPI) and the topology of the tertiary dispersion with gelatin and canola oil was also examined. Reproducible phase volume estimates were obtained, including those of the lipid phase, which were a close match to the actual concentrations added to the hydrocolloid gel. The approach could offer an alternative to the rheological estimation, via theoretical blending law analysis, of phase volumes in bio-composites. Graphical
PubDate: 2022-06-01
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- Effect of Process and Formulation Variables on the Structural and Physical
Properties in Cream Cheese using GDL Acidulant-
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Abstract: Abstract We report on the properties of analogue cream cheeses prepared using glucono delta-lactone (GDL) acidulant, notably the impact of particular processing and formulation variables, (homogenisation pressure, coagulation pH and temperature, and stabiliser level) on cream cheese physical, material and microstructural properties. Protein–protein and protein-fat interactions were seen to be the primary structural contributors to the physical properties of cream cheese. Cream cheese microstructure and its properties demonstrated well-defined correlations to specific and controllable processing elements within the manufacturing process, showing significance in interactions between parameters in multivariable linear regression analysis (P < 0.05). Summarising the effect of processing variables on key cheese properties, we observed that a progressive reduction in fat particle size of cheese milk arising from increasing homogenisation pressures was seen to increase the total surface area of fat that could be incorporated into the curd during coagulation. The greater extent of fat-fat and fat-proteins interactions during coagulation provided a reinforcing effect on the microstructure of the final cream cheese, with a corresponding increase in compressive fracture stress, shear storage modulus (G′) and shear loss modulus (G″). In terms of other processing variables, cream cheese firmness was also observed to progressively increase through lowering of coagulation pH from 5.13 to 4.33. Increasing coagulation temperature from 58 °C to 78 °C similarly caused an increase in cheese firmness. Finally, increasing the levels of added stabiliser were shown to correlate with increasing cheese firmness. Similar correlations could be observed in relation to physical properties, notably forced expressible serum separation. This model cream cheese preparation method has provided a useful model system for relating food structure to material and functional properties. In addition, it has the advantage of being able to rapidly screen many formulation and process variables because it is faster than the traditional cheesemaking. This study showed that the adjustment of process and formulation variables, either in isolation or in combination, in the manufacture of cream cheese can significantly influence the final material and textural properties of the product, thereby enabling controllable functional attributes capable of meeting different customer needs.
PubDate: 2022-06-01
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- Differential Influence of Microwave and Conventional Thermal Treatments on
Digestibility and Molecular Structure of Buckwheat Protein Isolates-
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Abstract: Abstract This study investigated the impact of heating and microwave treatment on the in vitro digestibility (using the INFOGEST method) of buckwheat protein isolates (BPIs) and explored the mechanism. The microwave treatment at level 4 (480 W) for 3 min (ML4T3) increased the BPI digestibility by 67.1% over that of the control, while heating for 20—40 min decreased the digestibility by 26.7% on average. Structural analysis showed that microwave treatment decreased the disulfide content, increased the sulfhydryl content, and distorted both the protein microstructure and surface morphology. Meanwhile, microwave treatment decreased the β-turn content and increased both the contents of the β-sheet structure by 35.6% and the random coil structure by 6.9%. In contrast, conventional heating increased the disulfide content and formation of aggregates, and decreased the contents of the random coil, α-helix and β-turn with concomitant increase in the β-sheet content. In conclusion, microwave treatment could be an effective approach to improve the digestibility of BPIs because of its multi-effects on the structure of proteins.
PubDate: 2022-06-01
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- Yellow and Black Soybean Pellet Degradation and Nutrients Hydrolysis
During In Vitro Gastrointestinal Digestion-
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Abstract: Abstract Pellet degradation and nutrients hydrolysis of yellow and black soybeans during in vitro digestion was monitored by particle size, microstructure, protein, starch and fat hydrolysis measurements. Similar changes were recorded in the particle sizes of both soybeans, with a slight increase in the gastric stage and a substantial increase in the intestinal phase, compared to the oral phase. Microscopy showed yellow soybeans were damaged more severely than black soybeans after digestion. Yellow soybeans released proteins at a higher rate during simulated gastric fluid digestion, while proteins from both sources were rapidly hydrolyzed at simulated intestinal fluid. The degree of starch hydrolysis was low (~ 25–35%), and free fatty acids rapidly accumulated during the first 15 min at simulated intestinal fluid (SIF), while the rate of release slowed down at the end. Small differences were found in the main components between two soybeans, as measured after soaking and steaming: protein, starch and lipid contents corresponded to 18.7 ± 1.0%, 7.3 ± 0.1%, 9.6 ± 0.6% (black soybean) and 16.3 ± 0.4%, 6.5 ± 0.1%, 8.7 ± 0.3% (yellow soybean) respectively; this explained their similar digestion behavior. This study adds insight on the fate of soybean particles in the digestive tract, and could provide reference for the structural and functional design of relevant plant-based foods.
PubDate: 2022-06-01
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- The melting properties of D-α-glucose, D-β-fructose, D-sucrose,
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Abstract: Abstract Saccharides are still commonly isolated from biological feedstock by crystallization from aqueous solutions. Precise thermodynamic data on solubility are essential to optimize the downstream crystallization process. Solubility modeling, in turn, requires knowledge of melting properties. In the first part of this work, following our previous work on amino acids and peptides, D-α-glucose, D-β-fructose, D-sucrose, D-α-galactose, and D-α-xylose were investigated with Fast Scanning Calorimetry (FSC) in a wide scanning rate range (2000 K·s−1 to 10000 K·s−1). Using the experimental melting properties of saccharides from FSC allowed successfully modeling aqueous solubility for D-sucrose and D-α-galactose with the equation of state PC-SAFT. This provides cross-validation of the measurement methods to determine accurate experimental melting properties with FSC. Unexpectedly, the experimental FSC melting temperatures, extrapolated to zero scanning rates for thermal lag correction, were higher than results determined with DSC and available literature data. To clarify this inconsistency, FSC measurements towards low scanning rates from 10000 K·s−1 to 1 K·s−1 (D-α-glucose, D-β-fructose, D-sucrose) overlapping with the scanning rates of DSC and literature data were combined. At scanning rates below 1000 K·s−1, the melting properties followed a consistent non-linear trend, observed in both the FSC and the literature data. In order to understand the non-linear decrease of apparent melting temperatures with decreasing heating rate, the endothermic peaks were investigated in terms of isoconversional kinetics. The activation energies in the non-linear dependency region are in the range of \(300<{E}_{A}< 600 {\text{kJ}}\bullet {\text{mo}}{\text{l}}^{-1}\) . These values are higher than the enthalpy of sublimation for D-α-glucose, indicating that the non-linear behavior does not have a physical nature but attributes to chemical processes corresponding to the decomposition of molecular compounds within the crystal lattice before melting. The melting properties reported in the literature, commonly determined with conventional methods such as DSC, lead to inaccurate results due to the decomposition of these biomolecules at low heating rates. In addition, the FSC results at lower scanning rates coincide with results from DSC and literature in the overlapping scanning rate range, further validating the accuracy of FSC measurements to determine reliable melting properties of thermally labile biomolecules. The experimental FSC melting properties determined at higher scanning rates are considered as the correct equilibrium melting properties, which are not influenced by any chemical processes. The combination of FSC and PC-SAFT opens the door to model solubility of solid compounds that commonly decompose before melting.
PubDate: 2022-06-01
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- Stabilizing Properties of Chia Seed Mucilage on Dispersions and Emulsions
at Different pHs-
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Abstract: Chia seeds mixed in water release a mucilaginous gel with stabilizing properties. However, the properties of dispersions and emulsions with chia mucilage at acid and basic conditions were not yet well described. Hence, this study aimed to evaluate the ability and characteristics of chia mucilage to form stable aqueous dispersions and soya oil–water emulsions at different pHs. The mucilage extraction yield was 3.76% (w/w), being composed of 8.33% (w/w) of moisture, 12.3% (w/w) of ash, 1.96% (w/w) of lipids and 13.4% (w/w) of proteins. Mucilage dispersions showed negative zeta potential over the entire pH range (1.5–8.5), reaching -40 mV at pH 8.5. Dispersions and emulsions with 1.0% (wt/wt) of chia mucilage showed pseudoplastic behavior in all pHs conditions evaluated (between 3.5 and 8.5). Viscosity, consistency index, emulsion droplet size, and emulsion viscoelastic properties increased with pH increment up to pH 6.5 and decreased at alkaline pHs. This behavior suggested that depolymerization of mucilage occurred at pH higher than 6.5, resulting in small molecules that produced low viscosity systems (dispersions and emulsions). Moreover, chia mucilage produced very stable dispersions, while emulsions showed low phase separation (up to 3,3% v/v), showing its use as an alternative ingredient to the development of new healthier acid, neutral and, alkaline products.
PubDate: 2022-05-11
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- Freeze Thaw Stability and Heat Stability of Coconut Oil-in-Water Emulsions
and Coconut Milk Emulsions Stabilized by Enzyme-Modified Soy Lecithin-
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Abstract: Abstract This study investigated effects of enzyme-modified soy lecithin (ESL) on freeze thaw stability and heat stability of coconut oil-in-water emulsions and coconut milk emulsions. Addition of ESL improved freeze thaw stability of coconut oil-in-water emulsions and coconut milk emulsions. Mean droplet sizes of coconut oil-in-water emulsions contained 20 wt% oil and 9 wt% ESL did not significantly alter after emulsions being frozen at -20 °C for 22 h and thawed at room temperature. Relatively similar fat crystallization patterns obtained from differential scanning calorimetry after three cooling-heating cycles (40 °C to -40 °C to 40 °C at 5 °C/min) confirmed high freeze thaw stability of coconut oil-in-water emulsions. Increasing concentrations of ESL to 9 wt% reduced amounts of destabilized oil in freeze thawed coconut milk emulsions substantially. Heat stability study shows that coconut oil-in-water emulsions and coconut milk emulsions stabilized by 9 wt% ESL remained remarkably stable after heating at 121 °C for 1 h observed by microscopy and mean droplet sizes. This work reveals that ESL contained mostly of unsaturated lysophospholipids reduced partial coalescence during freeze thawing process and reduced protein coagulation, droplets flocculation, and coalescence during heating process. ESL partially displaced and possibly interacted with interfacial coconut proteins which increased stability of coconut milk emulsions.
PubDate: 2022-04-30
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- Self-emulsifying Transparent Nanoemulsion to Improve 9'-cis-Bixin Photo
Stability in Aqueous Solution by Tween 20 and Lecithin-
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Abstract: Abstract Aqueous and photo stability of bixin are challenges in practical applications. Herein, transparent nanoemulsion can be self-emulsified to improve 9'-cis-bixin aqueous and photo stability. The 0.25 g carvacrol with 0.5% w/w 9'-cis-bixin, 2.08 g 12-% soybean lecithin, 2.25 g Tween 20, and 0.42 g water were mixed and stored overnight to fabricate transparent oil-in-water (O/W) nanoemulsion. The O/W nanoemulsion droplets had an average dimeter of 12.03 nm and equivalent spherical diameter of 6.78 nm. Photo stability of 9'-cis-bixin was improved after encapsulating in nanoemulsion droplets, demonstrated by significant improvement of 9'-cis-bixin degradation rate constant under ultraviolet. Nanoemulsion droplets significantly improved cell uptake of 9'-cis-bixin especially at the first 15 min after cocultivation of Caco-2 cells and 9'-cis-bixin encapsulated nanoemulsion. This study provides a comprehensive understanding of bixin protection by nanoemulsion fabricated by a self-emulsification method with potential cellular uptake.
PubDate: 2022-04-27
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- Effect of a polyphenol molecular size on the gluten proteins –
polyphenols interactions studied with FT-Raman spectroscopy-
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Abstract: Abstract Changes observed in the structure of gluten network as a results of dough supplementation with polyphenols may depend on the number and type of functional groups at the aromatic ring, antioxidant activity and size of the polyphenol molecule. The present studies show effect of polyphenols differing in the molecular size (gallic, ellagic and tannic acids) on the structure of gluten network studied with FT- Raman spectroscopy. The model dough was supplemented with the polyphenols in the amount of 0.05%, 0.1% and 0.2%. Farinographic studies showed that only gallic and ellagic acids led to dough breakdown, whereas tannic acid (the biggest molecule) stabilized the gluten network. Spectroscopic results indicate formation of covalent or hydrogen bonds between protein SH groups and polyphenol OH groups. Moreover, it was observed a strong negative band in all spectra that can be assigned to α-helices. It suggests that structural changes can concern mainly gliadins. When it comes to aromatic amino acids, the pattern of tyrosine hydrogen bonding was not affected by the polyphenols, whereas microenvironment of tryptophan changed considerably to more hydrophobic. It may indicate folding of polypeptide chains and development of more compact and ordered gluten network. The results indicated that disulphide bridges can be broken during the dough mixing and phenolic molecules formed bonds with SH groups of cysteine. This confirms inclusion of the polyphenols into the gluten network.
PubDate: 2022-04-25
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- Polyethylene Glycol Nanocapsules Containing Syzygium aromaticum Essential
Oil for the Management of Lesser Grain Borer, Rhyzopertha dominica-
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Abstract: In this study a green insecticide composed of polyethylene glycol (PEG) nanocapsules loaded with clove essential oil, Syzygium aromaticum was synthesized by melt-dispersion method. The produced dry nanocapsules were examined for their insecticidal activity against a major stored product pest Rhyzopertha dominica adults. Z-Average, polydispersity index (PDI), and encapsulation efficiency (%EE) of nanocapsules were characterized. The optimal oil:PEG ratio of 1:10 produced more stable nanocapsules with 215.87-237.37 nm, 0.26 − 0.23, and 89.54–87.95% particle size, PDI, and %EE during 1 day-6 months storage. Transmission electron microscopy image of optimal nanoformulation showed spherical in shape particles. Gas Chromatography–Mass Spectrometry analysis of clove essential oil identified eugenol as a major phytoconstituent. Four oil concentrations (250, 500, 750, and 1000 ppm) before and after loading-nanoparticles were tested for contact and ingestion toxicity. The toxicity study confirmed the effectiveness of clove essential oil nanocapsules against R. dominica after 72 h exposure time. The LC50 values were 175.50 and 576.85 ppm for nanocapsules and free clove oil, respectively. The toxicity index revealed that nanocapsules are 70% more toxic than free oil. The nutritional indices of treated insects were also affected. When compared to free clove oil, nanocapsules significantly decreased the tested nutritional parameters such as relative growth rate, relative consumption rate, and efficiency of conversion of ingested food. Also, the nanocapsules exhibited significant feeding deterrent index. The results of this study suggested that PEG nanocapsules as coating material enhanced the toxicity action of clove essential oil against R. dominica over long time. Graphical
PubDate: 2022-04-19
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- Impact of Phenolic Acid Derivatives on β-Lactoglobulin Stabilized
Oil-Water-Interfaces-
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Abstract: The physical stability of protein-based emulsions depends on intra- and intermolecular interactions of the interfacial protein-film. As studied in aqueous systems before, phenolic acid derivatives (PADs) non-covalently or covalently crosslink proteins depending on pH-value and thus, may impact interfacial protein-films. Whether these interactions occur in the same manner at the interface as in water and how they vary the properties of the interfacial protein-film has not been clarified. The present study aimed to investigate the interfacial protein-film viscoelasticity and physical emulsion-stability after non-covalently (pH 6.0) and covalently (pH 9.0) crosslinking depending on PAD-structure. For this purpose, we studied an interfacial β-lactoglobulin film with dilatational rheology after crosslinking with PADs, varying in number of π-electrons and polar substituents. Then, we analyzed the physical emulsion-stability by visual evaluation and particle size distribution. The results indicate that PADs with a high number of π-electrons (rosmarinic acid and chicoric acid) weaken the protein-film due to competing of phenol-protein interactions with protein-protein interactions. This is reflected in a decrease in interfacial elasticity. PADs with an additional polar substituent (verbascoside and cynarine) seem to further weaken the protein film, since the affinity of the PADs to the interface increases, PADs preferentially adsorb and sterically hinder protein-protein interactions. In emulsions at pH 6.0 and thus low electrostatic repulsion, PADs promote bridging-flocculation. Due to higher electrostatic repulsion at pH 9.0, the PADs are sterically hindered to form bridges, even though they are polymeric. Hence, our research enables the control of protein-film viscoelasticity and emulsion-stability depending on the PAD-structure. Graphical abstract
PubDate: 2022-04-11
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- Effective Production of Human Milk Fat Substitutes Rich in
1,3-Dioleoyl-2-palmitoyl Glycerol (OPO) viaa New Strategy-
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Abstract: Abstract 1,3-Dioleoyl-2-palmitoyl glycerol (OPO)-supplemented infant formulas mimic the nutritional properties of human milk, and thus are the best nutritional alternatives to breast feeding. Herein, structured triacyl glycerides rich in sn-1,3 oleic acid (OA) and sn-2 palmitic acid (PA) are synthesized via a new strategy by employing Rhizomucor miehei lipase (RML) adsorbed on magnetized multiwalled carbon nanotubes (mMWCNT) and synthesizing OPO-rich fats in a two-step enzymatic acidolysis. The results showed that the immobilized lipase (mMWCNT-COOH-RML) exhibited improved pH and thermal stability, and it could be separated conveniently from the reaction system via an external magnetic field. It also possessed a much better performance in catalysis of tripalmitin (PPP) with OA to synthesize OPO-rich fats in a two-step enzymatic acidolysis. Under optimized conditions, the content of palmitic acid at the sn-2 position and incorporation of OA at the sn-1,3 positions respectively reached 92.93% and 57.82%. mMWCNT-COOH-RML also exhibited better reusability and catalytic activity than the conventionally used commercial Lipozyme RM IM. The results indicate the employed new strategy for synthesis of OPO-rich fats has a prosperous potential in the application of infant formula formulations.
PubDate: 2022-04-08
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- Antioxidant and Antimicrobial Characterization of Active Films Based on
Yeast Biomass and Thymol-
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Abstract: Abstract Yeast biomass is a novel source for the production of biodegradable films and, joint to the incorporation of certain compounds from essential oils, it is possible to design promising active materials for food preservation. In this work, thymol was incorporated into yeast biomass matrices to develop bioactive films and this compound was satisfactory, retained by them without phase separation. IR spectra showed that thymol interacted with proteins and polysaccharides, but thymol did not substantially modify the mechanical properties, colour, and thermal decomposition of films. The active compound provided great antioxidant and antimicrobial capacity to the films. The inhibition of the ABTS•+ radical was higher than 80% by the addition of 8 or 10 wt% of thymol. Release of thymol from films to fatty food simulants at 4 °C, 25 °C, and 40 °C was fitted by the Crank model and diffusion coefficients at 40 °C were one order of magnitude higher than diffusion coefficients at 4 °C. Regarding antimicrobial activity, 10 wt% satisfactorily inhibited the growth of E. coli. The promising antioxidant and antimicrobial capacity of the active yeast biomass-thymol films could be used in the protection of fatty foods.
PubDate: 2022-04-07
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