Emulsifying properties of basil seed gum: Effect of pH and ionic strength

The recent progress in the research of extraction and functional applications of basil seed gum

Basil seed gum (BSG) is a new hydrophilic colloid of natural plant origin. Extracted from basil seeds, it possesses excellent functional characteristics in terms of emulsification, rheology, gelation, stability, and adsorption, which are just as favorable as those of certain commercial gums. Besides, BSG has been widely used in food, medicine, industry, and many other fields for its physiological functions of weight reduction, detoxification, and control of blood sugar and cholesterol as a good dietary fiber. In this paper, we analyzed and discussed the extraction procedures, composition structures, functional characteristics, and modification strategies of BSG. In addition, we summarized the latest research on the applications of BSG in different industries to provide theoretical references for the high-value processing and utilization of BSG.

Correlation between interfacial layer properties and physical stability of food emulsions: current trends, challenges, strategies, and further perspectives

Emulsions are thermodynamically unstable systems that tend to separate into two immiscible phases over time. The interfacial layer formed by the emulsifiers adsorbed at the oil-water interface plays an important role in the emulsion stability. The interfacial layer properties of emulsion droplets have been considered the cutting-in points that influence emulsion stability, a traditional motif of physical chemistry and colloid chemistry of particular significance in relation to the food science and technology sector. Although many attempts have shown that high interfacial viscoelasticity may contribute to long-term emulsion stability, a universal relationship for all cases between the interfacial layer features at the microscopic scale and the bulk physical stability of the emulsion at the macroscopic scale remains to be established. Not only that, but integrating the cognition from different scales of emulsions and establishing a unified single model to fill the gap in awareness between scales also remain challenging. In this review, we present a comprehensive overview of recent progress in the general science of emulsion stability with a peculiar focus on interfacial layer characteristics in relation to the formation and stabilization of food emulsions, where the natural origin and edible safety of emulsifiers and stabilizers are highly requested. This review begins with a general overview of the construction and destruction of interfacial layers in emulsions to highlight the most important physicochemical characteristics of interfacial layers (formation kinetics, surface load, interactions among adsorbed emulsifiers, thickness and structure, and shear and dilatational rheology), and their roles in controlling emulsion stability. Subsequently, the structural effects of a series of typically dietary emulsifiers (small-molecule surfactants,proteins, polysaccharides, protein-polysaccharide complexes, and particles) on oil-water interfaces in food emulsions are emphasized. Finally, the main protocols developed for modifying the structural characteristics of adsorbed emulsifiers at multiple scales and improving the stability of emulsions are highlighted. Overall, this paper aims to comprehensively study the literature findings in the past decade and find out the commonality of multi-scale structures of emulsifiers, so as to deeply understand the common characteristics and emulsification stability behaviour of adsorption emulsifiers with different interfacial layer structures. It is difficult to say that there has been significant progress in the underlying principles and technologies in the general science of emulsion stability over the last decade or two. However, the correlation between interfacial layer properties and physical stability of food emulsions promotes revealing the role of interfacial rheological properties in emulsion stability, providing guidance on controlling the bulk properties by tuning the interfacial layer functionality.

Biodegradable edible film based on basil seed gum: the effect of gum and plasticizer concentrations.. [DOI: 10.21203/rs.3.rs-2626369/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

In this research, edible films produced from basil seed gum (BSG) with 3 different gum (0.5%, 1%, 1.5%) and plasticizer concentrations (1%, 3%, 5%) were developed, and the physical, thermal, barrier and microstructural properties of these films were measured. As a result of XRD, AFM, DSC, and FT-IR spectroscopy analyses, it was concluded that the mechanical and barrier properties and thermal stability of BSG-based films are quite good. The increase in gum and glycerol concentrations increased the crystallinity also strengthened the mechanical and barrier properties of the film. Also, films with low gum and high glycerol ratio have almost smooth surfaces and appropriate transparency for packaging applications. As the glycerol and BSG concentration increased, WVP values of the films increased. The complete dissolution of this film in the soil within 60 days, even at the highest gum concentration, showed that this material could be considered eco-friendly packaging. For this reason, it is thought that BSG-based films and coatings with suitable gum and plasticizer concentrations can be a potential packaging material for foods since they can be obtained at low cost, have a very good barrier, thermal and structural properties, and are edible and biodegradable.

Atmospheric Pressure Cold Plasma Modification of Basil Seed Gum for Fabrication of Edible Film Incorporated with Nanophytosomes of Vitamin D3 and Tannic Acid

The purpose of this work was to first investigate the impact of cold plasma (CP) treatment, performed at various times (0-30 min), on the characteristics of basil seed gum (BSG), as well as the fabrication of functional edible films with the modified BSG. FT-IR spectra of CP-treated BSG revealed change at 1596 and 1718 cm^-1, indicating the formation of carbonyl groups. Both untreated and CP-modified BSG dispersions showed shear-thinning behavior with a higher apparent viscosity for the CP-modified dispersions at studied temperatures. Untreated BSG dispersion and the one treated by CP for 10 min revealed time-independent behavior, while those treated for 20 and 30 min showed a rheopectic behavior. CP-modified BSG dispersion had higher G', G″, and complex viscosity than untreated BSG. Higher contact angle for the CP-modified BSG suggested enhanced hydrophobic nature, while the surface tension was lower compared to the untreated BSG. SEM micrographs revealed an increase in the surface roughness of treated samples. Moreover, modified BSG was successfully used for the preparation of edible film incorporating tannic acid and vitamin D₃-loaded nanophytosomes with high stability during storage compared to the free form addition. The stability of encapsulated forms of vitamin D₃ and tannic acid was 39.77% and 38.91%, more than that of free forms, respectively. In conclusion, CP is an appropriate technique for modifying the properties of BSG and fabrication of functional edible films.

A novel promising delivery system for cuminaldehyde using gelled lipid nanoparticles: Characterization and anticancer, antioxidant, and antibacterial activities

This work aimed to develop a novel nanoencapsulation system for food colloidal formulations using gelled lipid nanoparticles (GLNs) to improve the functionality, stability, and bioactivity of cuminaldehyde as a highly volatile and poor hydrophilic food additive. Cuminaldehyde-loaded GLNs with diameters of 117-138 nm were fabricated through a hot emulsification process with monoglyceride (10 and 15 g/100 g lipid phase) as a lipid gelator at two concentrations of cuminaldehyde (500 and 1000 mg/L). All samples remained stable towards macroscopic phase separation and creaming during 28 days of storage at 4 °C, which could be related to the rigid structure of dispersed particles in the gelled state and retarding droplet movement. Moreover, all samples were stable to creaming after subjecting to the environmental changes including temperature (30, 60, and 90 °C for 30 min), ionic strength (100, 200, and 300 mM NaCl), and pH (3, 5, and 7). Measurement of apparent viscosity showed non-Newtonian shear thinning nature in all samples, which was more pronounced at higher concentrations of the gelator. Interestingly, higher cytotoxic effects of cuminaldehyde against human lung and colorectal cancer cells were observed after encapsulation within GLNs. However, weak toxicity was also found against normal peripheral blood mononuclearcells.On the other hand, the antioxidant activity and lipid oxidation stability were improved by increasing cuminaldehyde concentration, while it was reduced at higher monoglyceride concentration. All samples exhibited stronger antibacterial activity against Bacillus cereus than Eschershia coli. These findings suggest the significant potential benefits of GLNs as novel nanocarriers to enrich various food and beverage formulations with essential oils, flavors, and aromas.

Polysaccharide conjugates from Chin brick tea (Camellia sinensis) improve the physicochemical stability and bioaccessibility of β-carotene in oil-in-water nanoemulsions

A natural antioxidant emulsifier, tea polysaccharide conjugate (TPC), was isolated from Chin brick tea. The impact of TPC on β-carotene stability and bioaccessibility in oil-in-water nanoemulsions was assessed. TPC exhibited strong antioxidant activity and could be used to fabricate stable nanoemulsions (d < 140 nm). The extent of lipid digestion was considerably lower for lipid droplets coated by TPC (68%) than Tween 80 (94%) or whey protein isolate (WPI) (89%), probably because TPC formed interfacial layers that hindered the access of lipases to lipids. The chemical stability of β-carotene in TPC-nanoemulsions was markedly higher than in those formulated with Tween 80 or WPI due to the high antioxidant activity of TPC. The bioaccessibility of β-carotene (20-30%) was independent of emulsifier type. TPC from Chin brick tea can therefore be used as a dual-purpose functional ingredient in emulsified foods.

Extraction of basil seed mucilage using ionic liquid and preparation of AuNps/mucilage nanocomposite for catalytic degradation of dye

Basil seeds are widely cultivated throughout the world because of their extensive applications in various fields of life. The Basil seeds mucilage (BSM) exhibits remarkable physical and chemical properties like high water absorbing capacity, emulsifying, and stabilizing properties. The extraction of this mucilage from the seed surface has always been done by physical and chemical methods, which has certain drawbacks. Here, we report for the first time a chemical method for the effective extraction of this mucilage using ionic liquids (ILs); the green solvents. Pyridinium chloride based ILs were investigated for the effective extraction of mucilage and the process was optimized for various variables i.e. time, temperature, basil seed loading, co-solvents, anti-solvents. The extraction yield (up to 25% w/w of mucilage per basil seeds dry weight) was obtained at optimum conditions. Extracted mucilage was characterized by analytical techniques. The extracted BSM was used to prepare AuNps/BSM nanocomposite by stabilizing the gold nanoparticles. The AuNps/BSM nanocomposite was applied for the catalytic degradation of dyes (congo red; 12 min, methyl orange; 4 min, whereas 4-nitrophenol; 6 min).

The effect of pH on the chemical and structural interactions between apple polyphenol and starch derived from rice and maize

To date, how pH affects starch-polyphenol mixtures has not been thoroughly investigated. This study explored the impact of combining apple polyphenol (AP) with both normal rice starch (NRS) and normal maize starch (NMS) across a range of pH conditions. NRS-AP mixture particle sizes across a pH range of 3-8 varied from 169.9 ± 5.4 to 187.5 ± 6.9 μm, while for NMS-AP particles, these sizes ranged from 161.8 ± 8.0 to 176.0 ± 4.9 μm, indicating that the aggregation of starch-AP was inhibited under low pH condition. The melting enthalpy (△H) values of the NRS-AP mixture across a pH range of 3-8 were 8.50 ± 0.06-9.56 ± 0.12 J/g, while the corresponding value for the NMS-AP mixture was 5.77 ± 0.05-6.21 ± 0.08 J/g. FTIR analyses revealed that the degree of order of these starch-AP mixtures significantly decreased under low pH conditions. XRD analysis further revealed that both NRS-AP and NMS-AP mixtures exhibited V-type structures, and relative crystallinity levels decreased significantly under low pH conditions. Together, these results indicate that low pH values inhibit the recrystallization of NRS-AP and NMS-AP mixtures. Overall, these findings provide additional evidence regarding the interactions between AP and specific starches under a range of pH conditions.

Preparation and characterization of nanosized lignin from oil palm (Elaeis guineensis) biomass as a novel emulsifying agent

A study was carried out to determine the effectiveness of lignin, extracted from oil palm (Elaeis guineensis) biomass as water-in-oil (W/O) emulsifying agent. To achieve this goal, soda lignin (SL) was extracted via soda pulping process and a series of nanosized soda lignin (NSL) were prepared using homogenizer at three different speed i.e. 10,400 rpm (NSL 10), 11,400 rpm (NSL 11) and 12,400 rpm (NSL 12) for one hour. All prepared samples were characterized by FT-IR, UV-Vis spectroscopy, thermogravimetric analysis (TGA), zeta potential analyser, Transmission Electron Microscope (TEM) and Extreme High Resolution Field Emission Scanning Electron Microscope (XHR-FESEM). The result of FTIR showed that there is no prominent change occurred in spectra of all samples while a good stability was reflected by TGA curves. The percentage of creaming index and visual observations of all samples demonstrated that NSL 12 and dosage 2 g (out of 1 g, 1.5 g and 2 g) were found to be the best among all samples. Furthermore, the results of IFT indicate that NSL 12 was proven to be more stable than the commercial product. Therefore, NSL 12 is selected for toxicological studies and was found safe in both, in vitro and in vivo studies.

Physical Properties and Structural Changes of Myofibrillar Protein Gels Prepared with Basil Seed Gum at Different Salt Levels and Application to Sausages

The objective of this study was to evaluate physical properties and structural changes of myofibrillar protein gels with basil seed gum (BSG) at different salt levels and develop the low-salt sausages with BSG. Myofibrillar protein (MP) gels were prepared with or without BSG at different salt concentrations (0.15, 0.30, and 0.45 M). Cooking yield (CY, %), gel strength (GS, gf), viscosity, sulfhydryl contents, protein surface hydrophobicity, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) of MP were measured. Pork sausages were manufactured with 1% BSG at both low-salt (1.0%) and regular-salt (1.5%) levels. pH, color, expressible moisture (EM, %), CY, textural profile analyses, FTIR, sulfhydryl group, and protein surface hydrophobicity (μg) were measured for analyzing the properties of sausages. The addition of 1% BSG to MP gels increased CY and shear stress. Among treatments with different salt concentrations, MP at 0.30 M salt level with 1% BSG had higher GS than that at 0.15 M salt level with BSG. In microstructure, swollen structures were shown in MP gels with BSG. Although CY of sausage at the low-salt concentration (1.0%) decreased, regardless of the BSG addition, hardness values of sausages with regular-salt level increased with the addition of 1% BSG was added. Protein surface hydrophobicity and sulfhydryl contents of sausages increased with the addition of 1% BSG, resulting in higher hardness and lower springiness than those without BSG. These results suggest that BSG could be used as a water-binding and gelling agent in processed meats.

Solubility and emulsifying activity of yam soluble protein

Yam soluble protein (YSP) has been reported to have many physiological activities, such as scavenging free radicals, immune activation, and anti-hypertensive activities. Protein solubility and emulsifying activity are important protein-associated functional properties for the application of proteins in food systems. During this study, the factors of protein concentration, pH, temperature and salt concentration that influenced the solubility of YSP were investigated. As a result, the solubility was minimal near its isoelectric point (pH 3.5) and was highest at 45 °C in a temperature range of 40-60 °C. With an increase of protein concentration, the solubility decreased. According to the results of response surface methodology analysis, the interaction between pH and temperature on the solubility of YSP was significant, and the maximum solubility (87.5%) was obtained when the temperature was close to 40 °C, the pH was approximately 7 and the NaCl concentration approached 0.5 mol/L. As the protein concentration increased, the average particle size of the YSP emulsion decreased, and the particle size distribution gradually became balanced. Additionally, the microphotograph of the YSP emulsion reflected its distribution. The results of this study will provide data and a theoretical basis for the understanding of YSP's physicochemical properties and its application in the food industry.

Influence of different salts on rheological and functional properties of basil (Ocimum bacilicum L.) seed gum

In this paper, the influence of a variety of salts (NaCl, CaCl₂, and KCl) at different concentrations (0, 0.1, 0.5 and 1% w/w) on rheological and functional properties of basil seed gum (BSG) were investigated. BSG produced a high viscosity solution with yield stress, which was a function of salt type and concentration. In all samples, viscosity decreased as the electrostatic interactions between the BSG chains altered by salts. Flow behavior index increased by salt addition, which shows BSG had weaker shear-thinning behavior and worse mouthfeel in the presence of salts. The viscoelasticity of BSG strongly influenced by the addition of salt type as well as concentration. Larger cations (Ca⁺²) shield the electrostatic interaction between BSG chains more strongly compared to smaller cations as they have larger hydrated radius. As a result divalent salts decreased the viscosity and viscoelasticity more significantly. Emulsion capacity improved by salts addition, especially at high concentrations of salts. The foam capacity increased in the presence of CaCl₂ and KCl increased foaming capacity of BSG. The results suggest that the addition of the different types of salt can alter or modify the rheological and functional properties of BSG, depending on the salt concentration.

The Emulsifying Properties of Hydrogenated Rosin Xylitol Ester as a Biomass Surfactant for Food: Effect of pH and Salts

The xylitol ester of hydrogenated rosin (XEHR) was obtained for the first time from biomass-based hydrogenated rosin and xylitol using an environmentally friendly, high-pressure CO₂ catalytic synthesis. This compound is intended for use as an emulsifier for food. Analyses by ICP-AES showed the absence of heavy metal residues in the product, such that it met food standards. Fourier transform infrared and nuclear magnetic resonance spectroscopies together with gel permeation chromatography confirmed the successful esterification and the formation of a monoester and diester with molar masses of 427 and 772 g/mol. The emulsification of water/soybean oil mixtures by adding the XEHR was assessed at pH values of 4, 6.86, and 10 and in the presence of NaCl, KCl, MgCl₂, and CaCl₂. The XEHR was found to act as an emulsifier by reducing the interfacial tension of such mixtures to less than 2 mN/m under all conditions. The highest emulsifying activity index (9.52 m²/g) and emulsifying stability index (94.53%) were obtained after adding MgCl₂ (100 mM). Particle size and confocal microscopy showed that the presence of salts gave a more uniform droplet size and a finer emulsion structure. The high viscosities of the emulsions containing salts also suggested a more cohesive oil droplet network.

Flow behavior, thixotropy, and dynamic viscoelasticity of ethanolic purified basil (Ocimum bacilicum L.) seed gum solutions during thermal treatment

During processing, foodstuffs may be treated at various thermal operations. Thus, this study investigated the functional properties and flow behavior at operation conditions to ensure safety and improve quality and stability at high temperatures and analyzed the ability of gum to be used in food formulation. The results showed that the purified basil seed gum (PBSG) solutions could beknown as non-Newtonian liquids with pseudoplastic behavior. Frequency sweep revealed the storage modulus (G') was higher than the loss modulus (G″) in the treatments. According to stress sweep, frequency sweep, complex viscosity (η *), and loss-tangent (tan δ) outcomes, mechanical spectra of PBSG were categorized as weak gels. Besides, concentration and temperature were effect on G' and G″. The results indicated that, in general, 1% PBSG-121°C had the maximum yield stress, consistency coefficient (k), extent of thixotropy, and the minimum values of flow behavior index. Also, 1% PBSG showed the highest G', G″, η *, yield stress values at the limit of the LVE range (τy), flow-point stress (τf), and corresponding modulus G f (G' = G″), and the lowest value of tan δ. Exhibiting distinctive rheological characteristics of PBSG makes it as a worthy hydrocolloid to use in food products, which use thermal processing.