Oleofoams stabilized by monoacylglycerides: Impact of chain length and concentration.

Oleofoams are plant oil based whipped systems which have drawn academic and industry attention in recent years. The aim of this study was to determine the effect of fatty acid chain length and monoacylglyceride (MAG) concentration on the performance and structural properties of MAG-based oleofoams. Four different MAGs (monolaurin, monomyrystin, monopalmitin, and monostearin) were studied at three concentration levels (5, 10, and 15 wt%). The fatty acid chain length had a statistically significant impact on the size and shape of crystals formed, while higher MAG concentrations led to higher numbers of crystals in the continuous oil phase. These differences affected the performance and physical properties of the oleofoams: compared to other MAGs, monostearin based oleofoams were harder and exhibited higher values of G' and G″, had higher overrun and showed better stability. Lastly, through microscopy techniques it was successfully proved that monostearin-based oleofoams are stabilized by both bulk and Pickering stabilization.

Effect of treatment of Fusarium head blight infected barley grains with hop essential oil nanoemulsion on the quality and safety of malted barley.

Fusarium mycotoxin contamination of malting barley has been a persistent food safety issue for malting companies. In this study, the effect of hop essential oil (HEO) nanoemulsion on fungal biomass and mycotoxin production during the malting process was evaluated. Furthermore, the localization of fungal hyphae on the surface and inside the tissue of barley and malts was observed. The application of HEO nanoemulsion reduced fungal biomass and deoxynivalenol (DON) contents at each stage of the malting process as compared to control. During malting process, the fungal hyphae on kernel surfaces was reduced appreciably after steeping. However, the increment of hyphae was observed between the husk and testa layer of barley after germination than raw barley grains. In addition to its antifungal activity, the antioxidant activity of HEO in the treated malts suppressed the formation of aldehydes. This study lays the foundation for the utilization of HEO in the malting industry.

Nutraceutical potential of industrial hemp (Cannabis sativa L.) extracts: physicochemical stability and bioaccessibility of cannabidiol (CBD) nanoemulsions.

Cannabidiol (CBD) is one of the most promising functional food ingredients, which displays a number of health benefits. However, its low solubility and bioavailability impede its applications in functional foods. Herein, we developed a food-grade CBD nanoemulsion system using medium chain triacylglycerides (MCT), canola oil (CO), or hemp seed oil (HSO) as the carrier oil to compare the physicochemical stability and bioaccessibility of CBD. Encouragingly, all formulations were well maintained for 90 days under the tested temperatures (4, 25 and 37 °C) and pH values (3.5 and 7.0). Quantitative analysis of CBD during storage using high performance liquid chromatography revealed that the light exposure and acidity of the solution are two important factors affecting the chemical stability of CBD. Moreover, improved bioaccessibility of CBD in all three nanoemulsion formulations compared to that of bulk oil forms was confirmed, and the long chain triacylglyceride (LCT)-based nanoemulsion was superior to the MCT-based counterpart.

The viability of complex coacervate encapsulated probiotics during simulated sequential gastrointestinal digestion affected by wall materials and drying methods.

The objective of this study was to investigate the impact of protein type (sodium caseinate and pea protein isolate) and protein to sugar beet pectin mixing ratio (5 : 1 and 2 : 1) on complex coacervate formation, as well as the impact of the finishing technology (freeze-drying and spray-drying) for improving the viability of encapsulated Lactobacillus rhamnosus GG (LGG) in complex coacervates during simulated sequential gastrointestinal (GI) digestion. The physicochemical properties of LGG encapsulated microcapsules in liquid and powder form were evaluated. The state diagram and ζ-potential results indicated that pH 3.0 was the optimum pH for coacervate formation in the current systems. Confocal laser scanning microscopy (CLSM), viscoelastic analysis, and Fourier transform infrared spectroscopy (FTIR) confirmed that the gel-like network structure of the complex coacervates was successfully formed between the protein and SBP at pH 3.0 through electrostatic interaction. In terms of physiochemical properties and viability of LGG encapsulated in the microcapsule powder, the drying method played a crucial role on particle size, microstructure and death rate of encapsulated LGG during simulated sequential GI digestion compared to protein type and biopolymer mixing ratio. For example, the microstructure of spray-dried microcapsules exhibited smaller spherical particles with some cavities, whereas the larger particle size of freeze-dried samples showed a porous sponge network structure with larger particle sizes. As a result, spray-dried LGG microcapsules generally had a lower death rate during simulated sequential gastrointestinal digestion compared to their freeze-dried counterparts. Among all samples, spray-dried PPI-SBP microcapsules demonstrated superior performance against cell loss and maintained more than 7.5 log CFU per g viable cells after digestion.

Unlocking the potential of minimally processed corn germ oil and high oleic soybean oil to prepare oleogels for bakery application.

In this study, the influence of sunflower wax (SFX) concentration (1, 3, 5, 7, and 9 wt%) on the properties of oleogels prepared using expeller-pressed corn germ oil (EPC) or high oleic soybean oil (EPS) was comprehensively investigated. Overall, oleogels can be prepared from both EP oils at an SFX level ≥3 wt%. The strength of oleogels depends on SFX concentration. EPS oleogels had better rheological properties and a higher amount of platelet-like crystals than EPC oleogels. The characteristics of cookies prepared with both oleogels were evaluated and compared to cookies prepared with commercial shortening. The lipid distribution in the cookies as visualized by CLSM suggested that EPS oleogels with a 5 or 7 wt% SFX had a greater possibility of replacing commercial shortening as they exhibited even lipid distribution which enabled good air-incorporation and air retention abilities. This research provides a foundation for developing healthy bakery products by using minimally processed oil based oleogels.

Combining solid dispersion-based spray drying with cyclodextrin to improve the functionality and mitigate the beany odor of pea protein isolate.

The beany flavor of pea protein limits its application in the food industry. This study aimed at addressing this problem by combining the advantages of solid-based spray drying technique and the ability of cyclodextrins (CD) to entrap volatiles. Pea protein isolates (PPI) was extracted by alkaline extraction-isoelectric precipitation, followed by co-spray drying with CD. The resulted PPI-CD showed no major structure changes. HS-SPME-GC-MS coupled to untargeted metabolomics successfully identified 23 aroma compounds that represent the different odorants among PPI-control, physically mixed PPI-CD, and co-spray dried PPI-CD samples. Heat map analysis also showed a remarkable beany odor mitigation effect upon the addition of CD, which was further proved to be due to CD entrapping aroma compounds during spray drying. In the meantime, the functional attributes of PPI-CD were not adversely impacted by the addition of CD.

Physical properties and cookie-making performance of oleogels prepared with crude and refined soybean oil: a comparative study.

The objective of this research was to fabricate crude soybean oil oleogels (CSO) using ß-sitosterol (BS) and/or monoacylglycerol (MAG) and compare their role with that of refined soybean oil oleogels (RSO) in cookie making. Both crude and refined soybean oil oleogels were formed with BS or MAG, or the combination of both (1 : 1) at a fixed concentration of 10 wt%. The thermal behavior of the oleogels was measured using differential scanning calorimetry (DSC). The crystal structure and morphology of the oleogels were characterized using X-ray diffraction (XRD) and polarized light microscopy (PLM). The hardness of the oleogel and commercial vegetable shortening was compared using a texture analyzer. The characteristics of cookies made with the oleogels were compared with those of cookies made with commercial vegetable shortening. Overall, the incorporation of BS and/or MAG into crude and refined soybean oil can produce oleogels with solid-like properties. Refined soybean oil formed stronger and firmer oleogels as compared to crude soybean oil. RSO structured by BS presented branched fiber-like, elongated plate-like, and needle-like crystals while the same oil gelled by MAG contained spherulite crystals. RSO made with the combination of BS and MAG displayed crystal morphologies from both BS and MAG. The same crystal morphologies were observed in CSO with lower quantities. Comparing the quality of cookies made with the oleogels and commercial vegetable shortening, equal or better performance of both RSO and CSO in terms of weight, thickness, width, spread ratio, and hardness of cookies than that of commercial vegetable shortening was observed. By combining the results of the physical characterization and cookie making performance, it can be concluded that both crude and refined soybean oleogels could resemble commercial shortening, which offers the possibility of using oleogels to replace shortening in the baking industry.

Clove oil-in-water nanoemulsion: Mitigates growth of Fusarium graminearum and trichothecene mycotoxin production during the malting of Fusarium infected barley.

Fusarium mycotoxin contamination in malting barley is of great concerns in malting industry. Our recent study found that clove oil nanoemulsions can act as highly efficient antifungal agents in vitro. Therefore, we explored the efficacy of clove oil nanoemulsions on Fusarium growth and mycotoxin during malting process. The impact of emulsifier types (Tween 80, BSA and quillaja saponins) on the formation of clove oil nanoemulsion, the mitigation effects on mycotoxin levels and fungal biomass, and the clove oil flavor residues on malts were measured. We observed that 1.5 mg clove oil/g nanoemulsion showed a negligible influence on germinative energy of barley, while still efficiently eliminated the DON levels and toxicogenic fungal biomass as quantified by Tri5 DNA content. Tween 80-stablized clove oil nanoemulsion displayed higher mycotoxin inhibitory activity and less flavor impact on the final malt. The results indicated the potential application of essential oil nanoemulsion during the malting process.

Phase behavior and complex coacervation of concentrated pea protein isolate-beet pectin solution.

This study aimed to develop an alternative method named state diagram to identify boundary formation pH for complex coacervates between pea protein isolate (PPI) and sugar beet pectin (SBP) at concentrated solutions (~2.0 wt%). The effects of pH (7-2) and PPI-SBP mixing ratios (1:1-20:1) on coacervates formation were investigated by state diagram, zeta-potential, rheological, and phase composition analysis. Isothermal titration calorimetry, scanning electron microscopy, and Fourier transform infrared spectroscopy were employed to elucidate thermodynamic behaviors, non-covalent bonding of coacervates, and microstructure of coacervates. We demonstrate that state diagram can explicitly identify the three characteristic pH values (pHφ1, pHopt, and pHφ2) at which recognizable transitions take place in concentrated colloids solutions. The mixing ratio dependent of pHφ1 increased to pH 5.5 as PPI-SBP mixing ratio increased to 20:1. The pHopt was recognized at the net charge neutrality or the highest storage modulus of the mixed colloids solutions.

Formation, characterization, and potential food application of rice bran wax oleogels: Expeller-pressed corn germ oil versus refined corn oil.

The expeller-pressed (EP) corn germ oil oleogels were prepared using rice bran wax (RBX) at different concentrations (3, 5, 7, and 9 wt%). Their structural properties, including color, hardness, thermal behavior, rheological property, and crystal structure were evaluated. The performance of oleogels for potential food application was examined by incorporating oleogels into cookies as a fully replacement for commercial shortenings. Overall, RBX could form oleogels in both refined and EP corn germ oils at a concentration ≥3 wt%. Refined corn oil produced a stronger gel than crude corn oil. When comparing cookie characteristics, cookies made with both types of oleogels showed similar properties with commercial cookies. This result indicates that oleogels made by refined and EP corn germ oil together with RBX have the potential to imitate the functionality of commercial shortening in the baking industry.

Optimization and validation of in-situ derivatization and headspace solid-phase microextraction for gas chromatography-mass spectrometry analysis of 3-MCPD esters, 2-MCPD esters and glycidyl esters in edible oils via central composite design.

This study aimed to develop a headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) method for the quantification of 3-monochloropropane-1,2-diol fatty acid esters (3-MCPDEs) and 2-monochloropropane-1,3-diol fatty acid esters (2-MCPDEs), and semi-quantification of glycidyl fatty acid esters (GEs) in edible oils. A central composite design was implemented to optimize the derivatization temperature and extraction time, which were 100 °C and 80 min, respectively. HS-SPME coupled with in-situ derivatization was more straightforward (three steps) and sensitive, with a limit of detection of 16% (3.9 µg/L) and 11% (5.3 µg/L) higher than that of liquid injection method, for 3-MCPD and 2-MCPD, respectively. The recoveries of 3-MCPD and 2-MCPD were in the range of 91.1% to 102.1%, with a relative standard deviation ranging from 0.08 to 9.29%. The validated methodology was successfully applied to oil samples. Further efforts will focus on shortening the extraction time, as 80 min is relatively long.

Effect of germination time on antioxidative activity and composition of yellow pea soluble free and polar soluble bound phenolic compounds.

This research aims to study antioxidative activities of polar solvent extractable phenolic compounds from yellow peas with different germination times against oil-in-water emulsion oxidation. After germination (0, 2, 4, and 6 days), soluble free and polar soluble bound phenolic compounds were extracted and their antioxidative activity was evaluated using stripped soybean oil (SSO)-in-water emulsions. Liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF-MS) and size-exclusion chromatography with multiangle-light-scattering and refractive-index detection (SEC-MALS-RI) were employed to analyze the phenolic composition and molar mass, respectively. Antioxidative activities of soluble free phenolic compounds increased in the SSO-in-water emulsion system, while those of polar soluble bound phenolic compounds decreased with germination. On the basis of chemometric analysis, pratensein (2), phloridzin (4), quercetin (9), sayanedine (12), hesperetin (13), glyzaglabrin (14), and pinocembrin (15) were speculated as the pivotal phenolic compounds responsible for the hydrogen donating capacity. Additionally, decreased molecular weight of soluble bound phenolic compounds was accompanied by the reduction of antioxidative activity in SSO-in-water emulsions indicating that the moieties of polar soluble bound phenolic compounds also have an important impact on the antioxidative activity of phenolic compounds.

Influence of nonionic and ionic surfactants on the antifungal and mycotoxin inhibitory efficacy of cinnamon oil nanoemulsions.

The influence of ionic surfactants (cationic surfactant lauric arginate and anionic surfactant lysolecithin) on the physical properties, antifungal and mycotoxin inhibitory efficacy of Tween 80 stabilized cinnamon oil-in-water nanoemulsions was investigated. Nanoemulsion droplets of similar particle diameter (∼100 nm), but variable electrical characteristics, were formed by mixing 0.1 wt% ionic surfactant with 0.9 wt% Tween 80 before homogenization. The nanoemulsions were physically stable over 28 days at 23 °C. The antifungal activity (against mycelial growth and spore germination) and mycotoxin inhibitory activity of cinnamon oil nanoemulsions bearing positive, neutral, and negative charge surface was then evaluated against two chemotypes of Fusarium graminearum. In general, the cinnamon oil played a decisive role in the resulting antifungal and mycotoxin inhibitory activities. The surfactant charge had a limited impact on the antifungal mycotoxin inhibitory activities of cinnamon oil in the nanoemulsions. Both ionic surfactant-based cinnamon oil nanoemulsions showed greater activity in inhibiting mycelial growth and mycotoxin production of F. graminearum than those based on Tween 80. Treatment of mycelium with cinnamon oil nanoemulsions resulted in the loss of cytoplasm from fungal hyphae, and accounted for the antifungal action. These results have important implications for the design of essential oil based nanoemulsions as effective antifungal delivery systems in foods.

A combination of monoacylglycerol crystalline network and hydrophilic antioxidants synergistically enhances the oxidative stability of gelled algae oil.

In this study, base algae oil was gelled through the formation of a crystal network using food-grade monoacylglycerol (MAG). The impact of the MAG concentration (5, 10, 20 wt%) and water content (0, 5 wt%) on the physical properties and oxidative stability of the gelled algae oil was systematically investigated. The antioxidative activity of 300 µM hydrophilic antioxidant, i.e., ascorbic acid and green tea extract, on the oxidative stability of the gelled algae oil by 20 wt% of MAG was also examined. The results obtained clearly showed that the melting temperature, melting of entropy, and complex modulus of the algae oil increased with increasing the MAG concentration. The addition of 5 wt% water could negatively affect the strength of the MAG crystal network, while a physically stable gel system could only be formed with 20 wt% MAG. The stronger crystal network formed by 20 wt% MAG retarded the lipid oxidation of algae oil due to the creation of a physical barrier to restrain the attack from oxygen. The addition of green tea extract could further synergize with the MAG crystalline network by forming a thermodynamic barrier to effectively quench the radicals, thus prolonging the oxidative stability of algae oil 4-fold longer than that of the base algae oil.

Improvement of the Antioxidative Activity of Soluble Phenolic Compounds in Chickpea by Germination.

Our recent study found that antioxidative activity of phenolic compounds extracted from germinated chickpea was boosted in both in vitro assays and oil-in-water emulsions [ Xu et al. Food Chem. 2018 , 250 , 140 ]. The purpose of this study was to elucidate the mechanism by which germination enhances the antioxidative activity of the phenolic compounds extracted from chickpea. Liquid chromatography coupled with electrospray-ionization quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF-MS) and size-exclusion chromatography with multiangle-light-scattering and refractive-index detection (SEC-MALS-RI) were employed to evaluate the phenolic composition of soluble phenolic compounds (free and bound) and molar masses of soluble bound phenolic compounds, respectively, over 6 days of germination. According to principal-component analysis of the interrelationship between germination time and phenolic composition, it is revealed that protocatechuic acid 4- O-glucoside and 6-hydroxydaidzein played a pivotal role in the soluble free phenolic compounds, whereas gentisic acid and 7,3',4'-trihydroxyflavone were important in the soluble bound phenolic compounds. Molar masses of soluble bound phenolic compounds were increased after 6 days of germination. Protective and dual antioxidative effects were proposed to explicate how the antioxidative activity of soluble bound phenolic compounds in oil-in-water emulsions was improved with germination.

Influence of oil phase composition on the antifungal and mycotoxin inhibitory activity of clove oil nanoemulsions.

The influence of oil composition on the physical properties and antifungal and mycotoxin inhibitory activity of clove oil-in-water nanoemulsions was investigated. Physically stable clove oil-in-water nanoemulsions could be fabricated by incorporating either ≥75 wt% of corn oil or ≥50 wt% of medium chain triacylglycerol (MCT) into clove oil before homogenization to prevent Ostwald ripening. The clove oil-in-water nanoemulsions with mean diameters of <150 nm showed high physical stability over 30 days storage. The antifungal activity of physically stable clove oil nanoemulsions was further evaluated using effective concentration (EC) and inhibitory activity towards mycotoxin production in two chemotypes of Fusarium graminearum isolates. The composition of the oil phase, i.e., ripening inhibitor type and concentration, in clove oil-in-water nanoemulsions had a remarkable impact on antifungal activity as well as inhibition of mycotoxin production. In general, under the same clove oil concentration in oil phase, the addition of MCT decreased the antifungal and mycotoxin inhibitory activity of clove oil more than corn oil. Compared with the bulk clove oil, this study also indicated that the mycotoxin inhibitory activity of clove was significantly enhanced when encapsulated in nanoemulsions. These results have important implications for the design of essential oil based nanoemulsions as effective antifungal and detoxification delivery systems in the food or other industries.

The influence of pH and enzyme cross-linking on protein delivery properties of WPI-beet pectin complexes.

The incorporation of bioactive proteins and peptides into food is associated with the loss of bioactivity due to deactivation in complex food matrices and in digestion systems. In this study, two different types of protein carriers, i.e. biopolymer complexation and complex coacervation were fabricated using whey protein isolation (WPI, 6wt%) and beet pectin (BP, 1.25 and 1.00wt%) at pH5.5 and 3.5, respectively. The release of the encapsulated FITC-BSA, a model bioactive protein, in both carriers in the absence and presence of laccase was investigated at both pH7.0 and 4.0. Release of FITC-BSA from both lyophilized WPI-beet pectin biopolymer complexation and complex coacervation were biphasic with an initial burst release followed by a slower release phase. The addition of laccase in biopolymer complexation increased the loading efficiency from 44.95% to 52.15% and slowed down the burst release of FITC-BSA but did change the biphasic release pattern. Laccase-cross linked WPI (6wt%)-BP (1wt%) complex coacervation had highest FITC-BSA loading efficiency (96.90%). The release of the embedded FITC-BSA in this carrier at both pH4 and 7 was in a gradual manner and the profile can be fit to zero order kinetics over the 72h study period suggesting enzymatically reinforced complex coacervation between the protein and the negatively charged beet pectin can restrain the burst release of FITC-BSA. These results indicate that laccase cross-linked WPI-beet pectin complex coacervation can be a good carrier system for delivering hydrophilic bioactive proteins or peptides successfully with enhanced loading parameters and sustained release profiles.

Pulse seed germination improves antioxidative activity of phenolic compounds in stripped soybean oil-in-water emulsions.

The purpose of this study was to investigate antioxidative activity of phenolic compounds extracted from germinated pulse seed including chickpeas, lentils and yellow peas. Phenolic compounds were extracted at different germination time and total phenolic content was examined by Folin Ciocalteu's reaction. Antioxidative activity of extracts was characterized by in vitro assay including 2, 2-diphenyl-1-picrylhydrazyl radical scavenging capacity (DPPH), oxygen radical absorbance capacity (ORAC), iron-binding assay, and in stripped soybean oil-in-water emulsions. The results suggested that germination time is critical for phenolic compounds production. The form variation of phenolic compounds influenced the antioxidative activity of phenolic compounds both in vitro assay and in emulsion systems. Soluble bound phenolic compounds showed higher antioxidative ability in emulsion system with the order of chickpea > yellow pea > lentil. On the basis of these results, soluble bound phenolic compounds may be considered as a promising natural antioxidant to prevent lipid oxidation in foods.

Impact of diacylglycerol and monoacylglycerol on the physical and chemical properties of stripped soybean oil.

In this study, we determined the effect of diacylglycerol (DAG) and monoacylglycerol (MAG) on the oxidative stability of stripped soybean oil (SSO) and on the antioxidative effectiveness of α-tocopherol in SSO. We also examined the influence of DAG and MAG on the physical properties of SSO. DAG (0-2.5wt%) had little effect on the chemical stability of SSO and on the antioxidative activity of 40µM α-tocopherol in SSO (55°C). MAG (0-2.5wt%) had no remarkable impact on the chemical stability of SSO. The addition of MAG (0.5wt%) suppressed the effectiveness of α-tocopherol (40µM) in SSO. The addition of DAG did not cause an appreciable change in the interfacial tension (IFT) of SSO, indicating that it was not strongly surface active. MAG significantly decreased the interfacial tension of SSO, due to its strong surface active properties. Wide angle X-ray scattering (WAXS) analysis showed that DAG did not alter the structured organisation of SSO, which remained in an amorphous form, whereas MAG led to strong scattering, indicating the formation of crystals. The physical properties of DAG and MAG in the SSO may be related to the chemical stability of SSO and the effectiveness of antioxidants incorporated. These results can be used to better understand the physicochemical mechanisms by which minor components impact oxidation of bulk oils.

Design of foods with bioactive lipids for improved health.

Numerous studies have found an association between the consumption of certain bioactive lipids and improved human health, e.g., the prevention, delay, or treatment of chronic and acute diseases, such as cancer, cardiovascular disease (CVD), osteoporosis, and immune disorders. In this review, we discuss food-based sources and potential beneficial attributes of major dietary bioactive lipids: polyunsaturated fatty acids; carotenoids; phytosterols and phytostanols; and fat-soluble vitamins. We summarize the various challenges associated with incorporating these bioactive lipids into foods and beverages, such as poor water solubility, high melting point, and low chemical stability. Finally, we propose several techniques that have been used to solve the challenges and integrate dietary bioactive lipids into foods for improved health.