Vegetable protein isolate-stabilized emulsions for enhanced delivery of conjugated linoleic acid in Caco-2 cells

Encapsulation of conjugated linoleic acid and ruminant trans fatty acids to study the prevention of metabolic syndrome-a review

Studies have reported the potential benefits of consuming conjugated linoleic acid (CLA) and ruminant trans fatty acids (R-TFAs) in reducing the risk factors of metabolic syndrome (MetS). In addition, encapsulation of CLA and R-TFAs may improve their oral delivery and further decrease the risk factors of MetS. The objectives of this review were (1) to discuss the advantages of encapsulation; (2) to compare the materials and techniques used for encapsulating CLA and R-TFAs; and (3) to review the effects of encapsulated vs non-encapsulated CLA and R-TFAs on MetS risk factors. Examination of papers citing micro- and nano-encapsulation methods used in food sciences, as well as the effects of encapsulated vs non-encapsulated CLA and R-TFAs, was conducted using the PubMed database. A total of 84 papers were examined; of these, 18 studies were selected that contained information on the effects of encapsulated CLA and R-TFAs. The 18 studies that described encapsulation of CLA or R-TFAs indicated that micro- or nano-encapsulation processes stabilized CLA and prevented oxidation. CLA was mainly encapsulated using carbohydrates or proteins. So far, oil-in-water emulsification followed by spray-drying were the frequently used techniques for encapsulation of CLA. Further, 4 studies investigated the effects of encapsulated CLA on MetS risk factors compared with non-encapsulated CLA. A limited number of studies investigated the encapsulation of R-TFAs. The effects of encapsulated CLA or R-TFAs on the risk factors for MetS remain understudied; thus, additional studies comparing the effects of encapsulated and non-encapsulated CLA or R-TFAs are needed.

Esterified Soy Proteins with Enhanced Antibacterial Properties for the Stabilization of Nano-Emulsions under Acidic Conditions

Soy protein isolate (SPI), including β-conglycinin (7S) and glycinin (11S), generally have low solubility under weakly acidic conditions due to the pH closed to their isoelectric points (pIs), which has limited their application in acidic emulsions. Changing protein pI through modification by esterification could be a feasible way to solve this problem. This study aimed to obtain stable nano-emulsion with antibacterial properties under weakly acidic conditions by changing the pI of soy protein emulsifiers. Herein, the esterified soy protein isolate (MSPI), esterified β-conglycinin (M7S), and esterified glycinin (M11S) proteins were prepared. Then, pI, turbidimetric titration, Fourier transform infrared (FTIR) spectra, intrinsic fluorescence spectra, and emulsifying capacity of esterified protein were discussed. The droplet size, the ζ-potential, the stability, and the antibacterial properties of the esterified protein nano-emulsion were analyzed. The results revealed that the esterified proteins MSPI, M7S, and M11S had pIs, which were measured by ζ-potentials, as pH 10.4, 10.3, and 9.0, respectively, as compared to native proteins. All esterified-protein nano-emulsion samples showed a small mean particle size and good stability under weakly acidic conditions (pH 5.0), which was near the original pI of the soy protein. Moreover, the antibacterial experiments showed that the esterified protein-based nano-emulsion had an inhibitory effect on bacteria at pH 5.0.

Improving Pea Protein Emulsifying Capacity by Glycosylation to Prepare High-Internal-Phase Emulsions

Pea protein has been extensively studied because of its high nutritional value, low allergenicity, environmental sustainability, and low cost. However, the use of pea protein in some food products is hindered due to the low functionality of pea protein, especially as an emulsifier. High-internal-phase emulsions (HIPEs) are attracting attention because of their potential application in the replacement of hydrogenated plastic fats in foods. In this study, the use of glycated pea protein isolate (PPI) as an emulsifier to prepare HIPEs is proposed. The functionalization of a commercial PPI in two ratios of maltodextrin (MD) (1:1 and 1:2) via glycosylation (15 and 30 min), to act as an emulsifier in HIPEs, is investigated. HIPE properties, such as oil loss and texture, were evaluated and related to microstructural properties. Glycated-PPI-stabilized HIPEs showed high consistency, firmness, viscosity, and cohesiveness values; a tight and homogeneous structure; and physical stability throughout storage. The results showed that emulsions were more stable when using a 1:2 ratio and 30 min of heat treatment. However, the reaction time was more determinant for improving the textural properties when a 1:1 ratio was used for glycosylation than when a 1:2 ratio was used. Glycosylation with MD via the Maillard reaction is a suitable method to enhance the emulsifying and stabilizing properties of PPI.

The structure, antioxidant and antibacterial properties of thiol-modified soy protein isolate induced by allicin

This study investigated the effect of allicin binding on the structure, antioxidant and antibacterial properties of soy protein isolate (SPI). Results showed that allicin bound to 82.6 % free thiol groups of SPI at a molar ratio of 0.5. The combination of allicin and SPI significantly affected the structure of protein. Result of circular dichroism showed that the content of α-helix decreased by 26.9 % and the content of β-sheet increased by 12.2 % over control when the molar ratio was 0.5. The result of surface hydrophobicity signified the unfolding of SPI with the action of allicin. These results implied that allicin binding might be a suitable method for the modification of SPI. Furthermore, the antibacterialand antioxidant experiments indicated that allicin-SPI conjugates not only had the capacity to inhibit the growth of Escherichia coli and Staphyloccocus aureus, but also had DPPH and ABTS radicals scavenging activities.

A Comparative Functional Analysis of Pea Protein and Grass Carp Protein Mixture via Blending and Co-Precipitation

Currently, the application of protein mixture derived from plants and animals is of great interest to the food industry. However, the synergistic effects of isolated protein blends (BL) are not well established. Herein, the development of a more effective method (co-precipitation) for the production of protein mixtures from pea and grass carp is reported. Pea protein isolate (PPI), grass carp protein isolate (CPI), and pea–carp protein co-precipitates (Co) were prepared via isoelectric solubilization/precipitation using peas and grass carp as raw materials. Meanwhile, the BL was obtained by blending PPI with CPI. In addition, the subunit composition and functional properties of Co and BL were investigated. The results show that the ratios of vicilin to legumin α + β and the soluble aggregates of Co were 2.82- and 1.69-fold higher than that of BL. The surface hydrophobicity of Co was less than that of BL, PPI, and CPI (p < 0.05). The solubility of Co was greater than that of BL, PPI, and CPI (p < 0.05), and the foaming activity was higher than that of BL and CPI (p < 0.05) but slightly lower than that of PPI. In addition, based on the emulsifying activity index, particle size, microstructure, and viscosity, Co had better emulsifying properties than BL, PPI, and CPI. The study not only confirmed that co-precipitation was more effective than blending for the preparation of mixed protein using PPI and CPI but also provided a standard of reference for obtaining a mixture of plant and animal proteins.

Physiological fluid interfaces: Functional microenvironments, drug delivery targets, and first line of defense

Fluid interfaces, i.e. the boundary layer of two liquids or a liquid and a gas, play a vital role in physiological processes as diverse as visual perception, oral health and taste, lipid metabolism, and pulmonary breathing. These fluid interfaces exhibit a complex composition, structure, and rheology tailored to their individual physiological functions. Advances in interfacial thin film techniques have facilitated the analysis of such complex interfaces under physiologically relevant conditions. This allowed new insights on the origin of their physiological functionality, how deviations may cause disease, and has revealed new therapy strategies. Furthermore, the interactions of physiological fluid interfaces with exogenous substances is crucial for understanding certain disorders and exploiting drug delivery routes to or across fluid interfaces. Here, we provide an overview on fluid interfaces with physiological relevance, namely tear films, interfacial aspects of saliva, lipid droplet digestion and storage in the cell, and the functioning of lung surfactant. We elucidate their structure-function relationship, discuss diseases associated with interfacial composition, and describe therapies and drug delivery approaches targeted at fluid interfaces. STATEMENT OF SIGNIFICANCE: Fluid interfaces are inherent to all living organisms and play a vital role in various physiological processes. Examples are the eye tear film, saliva, lipid digestion & storage in cells, and pulmonary breathing. These fluid interfaces exhibit complex interfacial compositions and structures to meet their specific physiological function. We provide an overview on physiological fluid interfaces with a focus on interfacial phenomena. We elucidate their structure-function relationship, discuss diseases associated with interfacial composition, and describe novel therapies and drug delivery approaches targeted at fluid interfaces. This sets the scene for ocular, oral, or pulmonary surface engineering and drug delivery approaches.

Enhancement of physicochemical and encapsulation stability of O1/W/O2 multiple nanoemulsions loaded with coenzyme Q10 or conjugated linoleic acid by incorporating polyphenolic extract

Multiple O1/W/O2 nanoemulsions and O1/W nanoemulsions fortified with CLA or CoQ10 were produced using extra virgin olive or olive pomace oil and were also incorporated with polyphenols extracted from olive kernel to enhance their kinetic and chemical stability. They were prepared using a high-speed ultrasonic homogenizer. Specifically, nanoemulsions with 6 wt% lipid phase and 6 wt% non-ionic emulsifier (Tween 40) were produced and they demonstrated a droplet diameter >200 nm and high encapsulation stability during 30 days of storage at 4 °C or 25 °C. The incorporation of CLA or CoQ10 and polyphenolic compounds facilitated the homogenization of emulsions, reducing the droplet size and enhancing their chemical stability, and their bioactive retention values were >79%. O1/W/O2 nanoemulsions were produced using a mixture of non-ionic emulsifiers (Span 20 and Tween 40) and the O1/W enriched nanoemulsion as the dispersed phase. All multiple emulsions showed a bimodal droplet size distribution and Newtonian behavior while polyphenols facilitated their homogenization. Both vegetable oils resulted in samples with high kinetic and chemical stability; the bioactive retention values were found to be >80% at the end of 30 days of storage at 4 °C or 25 °C. Extra virgin olive oil resulted in more stable nanoemulsions in regards to kinetic and chemical stability at 4 °C, showing limited creaming and sedimentation boundary. Multiple nanoemulsions with the lowest initial droplet size presented the lowest droplet diameter growth and phase separation and the highest retention values. By comparing O1/W nanoemulsions and O1/W/O2 nanoemulsions, we noted that the reduction in the total phenolic content and antioxidant activity during storage was higher in the O1/W type. However, both delivery systems protected CLA and CoQ10 presenting high retention during storage. FTIR spectra before and after ultrasonic homogenization indicated that the sonication process did not significantly affect the lipid phase of O1/W/O2 nanoemulsions.

Proteins from leguminous plants: from structure, property to the function in encapsulation/binding and delivery of bioactive compounds

Leguminous proteins are important nutritional components in leguminous plants, and they have different structures and functions depending on their sources. Due to their specific structures and physicochemical properties, leguminous proteins have received much attention in food and nutritional applications, and they can be applied as various carriers for binding/encapsulation and delivery of food bioactive compounds. In this review, we systematically summarize the different structures and functional properties of several leguminous proteins which can be classified as ferritin, trypsin inhibitor, β-conglycinin, glycinin, and various leguminous proteins isolates. Moreover, we review the development of leguminous proteins as carriers of food bioactive compounds, and emphasize the functions of leguminous protein-based binding/encapsulation and delivery in overcoming the low bioavailability, instability and low absorption efficiency of food bioactive compounds. The limitations and challenges of the utilization of leguminous proteins as carriers of food bioactive compounds are also discussed. Possible approaches to resolve the limitations of applying leguminous proteins such as instability of proteins and poor absorption of bioactive compounds are recommended.

Legume proteins are smart carriers to encapsulate hydrophilic and hydrophobic bioactive compounds and probiotic bacteria: A review

Encapsulation is a promising technological process enabling the protection of bioactive compounds against harsh storage, processing, and gastrointestinal tract (GIT) conditions. Legume proteins (LPs) are unique carriers that can efficiently encapsulate these unstable and highly reactive ingredients. Stable LPs-based microcapsules loaded with active ingredients can thus develop to be embedded into processed functional foods. The recent advances in micro- and nanoencapsulation process of an extensive span of bioactive health-promoting probiotics and chemical compounds such as marine and plant fatty acid-rich oils, carotenoid pigments, vitamins, flavors, essential oils, phenolic and anthocyanin-rich extracts, iron, and phytase by LPs as single wall materials were highlighted. A technical summary of the use of single LP-based carriers in designing innovative delivery systems for natural bioactive molecules and probiotics was made. The encapsulation mechanisms, encapsulation efficiency, physicochemical and thermal stability, as well as the release and absorption behavior of bioactives were comprehensively discussed. Protein isolates and concentrates of soy and pea were the most common LPs to encapsulate nutraceuticals and probiotics. The microencapsulation of probiotics using LPs improved bacteria survivability, storage stability, and tolerance in the in vitro GIT conditions. Moreover, homogenization and high-pressure pretreatments as well as enzymatic cross-linking of LPs significantly modify their structure and functionality to better encapsulate the bioactive core materials. LPs can be attractive delivery devices for the controlled release and increased bioaccessibility of the main food-grade bioactives.

In vitro gastrointestinal digestion and cytotoxic effect of ovalbumin-conjugated linoleic acid nanocomplexes

The aim of this work was to examine the behavior of conjugated linoleic acid (CLA) delivery systems based on ovalbumin (OVA) and their derived nanoparticles (OVA_n1 and OVA_n2), under static in vitro gastrointestinal digestion model. In addition, potential cytotoxic effect of these inclusion complexes on a human colon cancer cell line (HT-29) was evaluated. OVA was resistant to gastric and intestinal digestion, while OVA nanoparticles were very susceptible to digestive enzymes hydrolysis. Particle size distribution (PDS) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) for OVA evidenced the presence of a protein fragment of similar size after simulated digestive process. Conversely, for nanoparticles, partial and total hydrolysis in gastric and intestinal phases, respectively, was evidenced. After in vitro gastrointestinal digestion, released CLA (R_CLA) was assayed. In case of OVA, as CLA carrier, R_CLA was 37%, while for OVA nanoparticles, lower R_CLA values (~10-20%) were obtained. From cytotoxic assays, it was observed that CLA molecule was responsible for cell death, whereas OVA or their derived nanoparticles were not cytotoxic on HT-29 cells. On the other hand, flow cytometry analysis revealed that main death mechanism for CLA, and their inclusion complexes was apoptosis. OVA-CLA and OVA_n1-CLA inclusion complexes displayed the highest potential cytotoxic activity and apoptotic index. Information derived from this work could be relevant for the design of CLA delivery systems as promising nanosupplements for production of new functional and excipient foods for both prevention and control of colon cancer.

Protein matrices ensure safe and functional delivery of rosmarinic acid from marjoram (Origanum majorana) extracts

BACKGROUND

To understand the interactions between carriers and functional ingredients is crucial when designing delivery systems, to maximize bioefficacy and functionality. In this study, two different protein matrices were evaluated as means to protect the extract isolated from marjoram leaves (Origanum majorana), casein micelles from fresh skim milk and soy protein isolate (SPI).

RESULTS

Marjoram extract was obtained from pressurization of ethanol and water solvent. Protein dispersions of casein and SPI (5 g L-1 each) with or without marjoram extract (0.1-3 mg mL-1 ) were prepared and homogenized. The physicochemical characterization of charge and entrapment efficiency were conducted. The results demonstrated that entrapment efficiency was highly dependent on the carrier itself where SPI formulations showed 20% higher affinity when compared to casein micelles. To investigate the physiological behaviour of the marjoram-protein dispersions, human macrophages were employed. A non-specific inflammatory response of macrophages stimulated with bacterial lipopolysaccharide was measured for TNF-α, IL-1β and IL-6 cytokine secretion.

CONCLUSION

Casein and SPI protein formulations warranted high bioefficacy of marjoram extract, showing their potential as safe carriers. © 2018 Society of Chemical Industry.

DHA rich algae oil delivered by O/W or gelled emulsions: strategies to increase its bioaccessibility

BACKGROUND

The bioaccessibility of bioactive compounds for functional food deserves evaluation. An in vitro gastrointestinal digestion model was applied to provide information about the extent of lipid hydrolysis, oxidative stability and bioaccessibility of algae oil (42% of docosahexaenoic acid; DHA), comparing three lipid delivery systems: bulk oil, soy protein stabilized O/W emulsion and carrageenan gelled emulsion.

RESULTS

Lipid digestion kinetics was slightly influenced by the delivery systems. Nevertheless, at the end of intestinal digestion, lipolysis in the three samples ranged between 49% and 52%, showing a partial oil digestion. Lipid oxidation, measured by malondialdehyde, was significantly lower (P < 0.01) in both emulsified oils after intestinal digestion compared to the bulk oil. Bioaccessibility of DHA was 58%, 71% and 84% for bulk oil, O/W emulsion and gelled emulsion, respectively.

CONCLUSION

These results suggest that both emulsified delivery systems used in the present study enhanced the solubilization of free fatty acids, in particular omega-3 fatty acids, and therefore their potential intestinal absorption. © 2018 Society of Chemical Industry.

INFOGEST static in vitro simulation of gastrointestinal food digestion

Developing a mechanistic understanding of the impact of food structure and composition on human health has increasingly involved simulating digestion in the upper gastrointestinal tract. These simulations have used a wide range of different conditions that often have very little physiological relevance, and this impedes the meaningful comparison of results. The standardized protocol presented here is based on an international consensus developed by the COST INFOGEST network. The method is designed to be used with standard laboratory equipment and requires limited experience to encourage a wide range of researchers to adopt it. It is a static digestion method that uses constant ratios of meal to digestive fluids and a constant pH for each step of digestion. This makes the method simple to use but not suitable for simulating digestion kinetics. Using this method, food samples are subjected to sequential oral, gastric and intestinal digestion while parameters such as electrolytes, enzymes, bile, dilution, pH and time of digestion are based on available physiological data. This amended and improved digestion method (INFOGEST 2.0) avoids challenges associated with the original method, such as the inclusion of the oral phase and the use of gastric lipase. The method can be used to assess the endpoints resulting from digestion of foods by analyzing the digestion products (e.g., peptides/amino acids, fatty acids, simple sugars) and evaluating the release of micronutrients from the food matrix. The whole protocol can be completed in ~7 d, including ~5 d required for the determination of enzyme activities.

Simulated gastrointestinal digestion of inclusion complexes based on ovalbumin nanoparticles and conjugated linoleic acid

Ovalbumin delivery system of conjugated linoleic acid resists in vitro gastrointestinal digestion with high percentages of bioactive retention.

Tyrosinase-crosslinked pea protein emulsions: Impact of zein incorporation

The effect of tyrosinase-crosslinking of pea protein and pea-zein complexes on the properties of concentrated o/w emulsions was studied in the present work. Emulsions comprising 2% pea protein (w/w) solubilized in the aqueous phase (60% w/w) with or without zein solubilized in the oil phase (40% w/v), were fabricated by using high pressure homogenization. Tyrosinase treated emulsions (TyrBm-crosslinked) and non-crosslinked emulsions were evaluated after 2 h of incubation. Crosslinked pea protein stabilized emulsions led to better stability, larger particle size, increased viscosity and a paste-like structure, compared to non-crosslinked pea protein stabilized emulsions. Zein incorporation in the crosslinked pea-zein stabilized emulsions, contributed to significant improvement of stability and an increase in G' concurrently with a gel-like structure formation (G' > G″), compared to the non-crosslinked pea-zein and crosslinked pea protein stabilized emulsions. In general, crosslinked emulsions showed higher protein adsorption percentage compared to non-crosslinked emulsions, while the fraction adsorbed at the oil/water interface contained crosslinked convicilin/vicilin and zein fractions. Altogether, results demonstrate that enzymatic covalent bond formation in pea protein or zein-pea protein complexes is a useful approach to design and formulate sauces, cheese and meat replacements, and other vegetarian or vegan emulsion based foods. In addition, this work represents a step forward in application of functionalized zein in concentrated oil-in-water-emulsions.

Micro- and nano bio-based delivery systems for food applications: In vitro behavior

Micro- and nanoencapsulation is an emerging technology in the food field that potentially allows the improvement of food quality and human health. Bio-based delivery systems of bioactive compounds have a wide variety of morphologies that influence their stability and functional performance. The incorporation of bioactive compounds in food products using micro- and nano-delivery systems may offer extra health benefits, beyond basic nutrition, once their encapsulation may provide protection against undesired environmental conditions (e.g., heat, light and oxygen) along the food chain (including processing and storage), thus improving their bioavailability, while enabling their controlled release and target delivery. This review provides an overview of the bio-based materials currently used for encapsulation of bioactive compounds intended for food applications, as well as the main production techniques employed in the development of micro- and nanosystems. The behavior of such systems and of bioactive compounds entrapped into, throughout in vitro gastrointestinal systems, is also tracked in a critical manner. Comparisons between various in vitro digestion systems (including the main advantages and disadvantages) currently in use, as well as correlations between the behavior of micro- and nanosystems studied through in vitro and in vivo systems were highlighted and discussed here for the first time. Finally, examples of bioactive micro- and nanosystems added to food simulants or to real food matrices are provided, together with a revision of the main challenges for their safe commercialization, the regulatory issues involved and the main legislation aspects.