Modified Soy Protein Isolate Research Articles

Advancing self‐healing soy protein hydrogel with dynamic Schiff base and metal‐ligand bonds for diabetic chronic wound recovery

AbstractTo address the unique challenges of diabetic wound healing, wound dressings, particularly multifunctional hydrogels have garnered considerable interest. For the first time, a novel environmentally friendly soy protein‐based hydrogel is developed to accelerate the healing of diabetic chronic wounds. Specifically, this hydrogel framework is in direct formation through the dynamic Schiff base between oxidized guar gum and epigallocatechin‐3‐gallate (EGCG)‐modified soy protein isolate. Meantime, the addition of Ag+ enhances the cross‐linking of the hydrogel network by forming metal‐ligand bonds with the catechol groups in EGCG. Interestingly, the stretchability (up to 380%), swelling, and rheology properties of the hydrogel can be controlled by fine‐tuning the density of metal‐ligand bonds, endowing them with a high potential for precise matching. Additionally, various dynamic bonds endow hydrogel with excellent self‐healing ability, adhesiveness, and injectability. This hydrogel also exhibits good antibacterial properties, biocompatibility, and cell migration capabilities. Both in vivo and in vitro experiments demonstrated the outstanding anti‐inflammatory capacity of the hydrogel and its ability to modulate macrophage polarization. Consequently, the hydrogel has proven effective in promoting wound healing in a diabetic full‐thickness wound model through enhanced angiogenesis and collagen deposition. This eco‐friendly plant protein hydrogel offers a sustainable solution for wound care and environmental protection.

Structural characterization of modified soy protein isolate composite coatings and its application on fresh-cut cantaloupe (Cucumis melo cv. Xiaomi)

Fresh-cut cantaloupe is very perishable due to the mechanical damage and susceptibility to microorganism infections, which limit their shelf life. Cantaloupe is a popular fruit with high moisture content and nutritional value. This study aimed to enhance fresh-cut cantaloupe quality and extend the shelf life by employing soy protein isolates (SPI) coating solutions containing calcium lactate (CaL) and λ-aminobutyric acid (GABA). Cold plasma (CP) was used to augment the antioxidant and antimicrobial activities of the coatings. The coatings were meticulously characterized, and their impact on fresh-cut cantaloupe was assessed through physicochemical and microbiological parameters. The incorporation of CaL and GABA and the CP treatment heightened the antioxidant activity of the SPI coating, resulting in a substantial increase in DPPH and ABTS free radical scavenging activities by 58% and 30%, respectively. Application of the composite coating included a noteworthy 24% reduction in water loss on fresh-cut cantaloupe, maintaining color stability and total soluble solids content. Moreover, the treatment of composite coating effectively controlled microbial growth, ensuring fresh-cut cantaloupe remained in an edible state at the conclusion of the storage period. The coating treatment has extended the shelf life of fresh-cut cantaloupe from 6 d to 10 d at 0 °C. In conclusion, the CP-treated bioactive coating containing CaL and GABA prolonged the shelf life, enhanced nutritional value, and preserved the microbial quality attributes of fresh-cut cantaloupe.

Co-delivery mechanism of curcumin/catechin complex by modified soy protein isolate: Emphasizing structure, functionality, and intermolecular interaction

Modifying proteins to enhance their affinity for polyphenols is essential for developing a practical and efficient delivery system that promotes the synergistic effects of bioactive substances. The study investigated the nanoparticle complexation in both pure soy protein isolate (SPI) or SPI modified by ultrasonic combined heat treatment (UHSPI) with varying concentrations of curcumin/catechin (CU/CA) complex, and its effects on the functionality, structure and conformational changes of protein-polyphenol nanocomplexes. Additionally, the intermolecular interaction and co-delivery mechanisms of nanocomplexes were analyzed. Results showed that the physical modification process (28/40 kHz, 90 °C, 15 min) and a rational concentration of CU/CA (0.6 mg/mL) improve the encapsulation efficiency of polyphenols by SPI (up to 77% for curcumin, and 93% for catechin), resulting in a higher DPPH and ABTS scavenging capacity, along with the highest emulsification activity index, as well as enhanced storage stability and thermal stability. The interaction between UHSPI and CU/CA disrupted the protein's secondary structure and exposed more hydrophobic residues to a hydrophilic environment, and exhibited stronger fluorescence quenching. Molecular docking analysis revealed that protein-polyphenol interactions primarily relied on hydrogen bonds and hydrophobic interactions, and 11S subunits exhibited higher affinity with CU/CA. FTIR, fluorescence spectra, and XRD further confirmed the enhanced interaction ability between UHSPI and CU/CA, resulting in the formation of a more stable nanocomplex. Overall, the modified SPI effectively facilitates the co-delivery of an appropriate concentration of curcumin/catechin complex.

Effect of flaxseed-derived diglyceride-based high internal phase Pickering emulsion on the quality characteristics of reformulated beef burgers

The study aimed to fabricate healthier beef burgers using high internal phase Pickering emulsion (HIPPE) as animal fat substitute. In this context, HIPPE stabilized by modified soy protein isolates was produced with flaxseed-derived diglycerides (DAGs). Beef burgers were prepared by substituting beef backfat with HIPPE at varying levels (0%, 25%, 50%, 75%, and 100%). Reformulated burgers showed a significant decrease in WHC (from 89.75 to 77.38%), pH (from 5.73 to 5.58), L* values (from 53.5 to 44.5), and b* values (22.9 to 21.8), while a significant increase in a* values (from 24.4 to 6.7), cooking loss (from 20.25 to 30.62), and cooking shrinkage (from 11.27 to 13.05). Texture attributes, including hardness, chewiness, and gumminess, decreased up to 50% fat substitution and increased with increasing levels of fat substitution. Moreover, the rheological properties (G′ and G′′) and T2 relaxation time were increased with increasing fat replacement. The reformulation with HIPPE resulted in a decrease in SFA (from 3896 to 1712 mg/100 g), ω-6/ω-3 ratio (from 5.29 to 0.47), atherogenic index (from 0.57 to 0.13), and thrombogenic index (from 1.46 to 0.15) and increase in PUFA/SFA ratio (from 0.20 to 2.79). Notably, burgers with 50% fat substitution were more preferred regarding tenderness, while those with 100% fat substitution obtained higher scores for color and flavor than all other treatments. In conclusion, 50% fat replacement using flaxseed-derived diglyceride-based HIPPE improved beef burgers' textural profile and fatty acid composition without compromising the sensory characteristics.

Performance of eco-friendly soy protein adhesive reinforced by aldehyde sodium alginate

Faced with many challenges such as energy crisis and environmental protection issues, biomass soy protein-based adhesives for replacing aldehyde-based adhesives have gradually become one of the research hotspots for wood industry upgrading. However, soy protein-based adhesives still have many shortcomings. Low bonding strength, poor water resistance and high viscosity restrict their widespread industrial application. In this work, a modified soy protein isolate (SPI) based adhesive with strong water-resistant bonding strength and low viscosity was prepared. Oxidized sodium alginate (OSA) and calcium ions were employed in SPI adhesive system. Results showed that cross-linking between OSA, calcium ions and SPI occurred successfully. The mechanical properties of SPI were significantly improved. The dry and wet bond strengths were 2.05 MPa and 0.97 MPa, respectively, in 65.3 % and 49.2 % increments for comparison. The adhesive samples also showed a reduction in viscosity and an increase in thermal stability. It can be developed as a facile method for preparing bio-adhesives.

Influence of varying oil phase volume fractions on the characteristics of flaxseed-derived diglyceride-based Pickering emulsions stabilized by modified soy protein isolate

This research aimed to create Pickering emulsions using modified soy protein isolate (SPI) as a stabilizer and flaxseed-derived diglyceride (DAG) as an oil phase. The SPI was modified through a process involving both heating and ultrasound treatment. The result indicated that the droplet size of emulsions increased with the increase in oil content (p < 0.05). For instance, the largest droplet size (23 µm) was observed at an oil-to-SPI dispersion ratio of 4:1 ratio (φ = 80), whereas the smallest droplet size (6.39 µm) was noticed at the 1:4 ratio. During the 7-day storage period, the emulsions with a 4:1 ratio (φ = 80) showed the lowest droplet size increase (from 23 µm to 25.58 µm). In contrast, the emulsions with a 1:1 ratio displayed the highest increase (from 19.39 µm to 74.29 µm). Creaming index results revealed that emulsions with a 4:1 ratio (φ = 80) showed no signs of creaming and phase separation than all other treatments (p < 0.05). Backscattering fluctuations (ΔBS) and turbiscan stability index (TSI) showed that emulsions with 4:1, 2:1, and 1:1 oil-to-SPI dispersion ratios had consistent ΔBS curves with higher and TSI curves with lower values. Optical microscopy, confocal laser scanning, and cryo-scanning electron microscopy revealed that emulsions with oil-to-SPI dispersion ratios of 4:1 and 2:1 had well-organized structures with no visible coalescence. Macromorphological and microrheological investigations demonstrated that emulsions with 80% oil content had the highest viscosity, both moduli, elasticity index, macroscopic viscosity index, and the lowest fluidity index and solid–liquid balance values. Moreover, these emulsions were more resistant to centrifugation and storage environments. In conclusion, the study determined that flaxseed-derived DAG-based high internal phase Pickering emulsions (φ = 80) had superior stability, improved viscoelasticity, and better rheological properties.

Development and characteristics of emulsion gels with microwave-assisted ferulic acid covalently modified soy protein: Structure, function and digestive properties

This work aims to investigate the effect of microwave-assisted ferulic acid (FA) covalently modified soy protein isolate (SPI), which acts as a stabilizer, upon the structural and functional properties of emulsion gel. The results showed that the microwave and FA covalently modified SPI could synergistically strengthen the colloidal properties of the system and improve its structure. The microwave-assisted FA covalently modified SPI maximized the absolute value of the ζ-potential (−33.5 ± 2.1 mV) and the thermal denaturation temperature (152.3 °C) of the system. In addition, the smaller system particle size (115.3 ± 3.3 nm) and the increase in irregular structure allowed the generation of stronger gel-like network structures in stable emulsion gel. The enhancement of uniform oil-water distribution and stability was also confirmed by LF-NMR and microstructure. The results of gastrointestinal digestion experiments showed that quercetin loaded on emulsion gels stabilized by SPI-FA-M promoted lipid hydrolysis and improved the bioaccessibility (from 20.0 ± 2.1% to 37.2 ± 1.5%) and stability (from 39.7 ± 1.3% to 78.3 ± 4.5%) of quercetin. Our findings provide a new perspective for understanding the potential applications of combined physical-chemical modified proteins as emulsion gels stabilizers in food delivery systems.

Effect of sodium trimetaphosphate on the physicochemical properties of modified soy protein isolates and its lutein‐loaded emulsion

Due to people's pursuit of healthy and green life, soy protein isolate (SPI) is occupying a larger and larger market share. However, the low solubility of SPI affects its development in the field of food and medicine. This paper aimed to investigate the effects of sodium trimetaphosphate (STMP) on the functional properties and structures of phosphorylated SPI and its lutein-loaded emulsion. After modification by STMP, the phosphorus content of phosphorylated SPI reached 1.2-3.61mg/g. Infrared spectrum and X-ray photoelectron spectrum analysis confirmed that PO4 3- had phosphorylation with -OH in serine of SPI molecule. X-ray diffraction analysis showed that phosphorylation destroyed the crystal structure of protein molecules. Zeta potential value of phosphorylated SPI decreased significantly. When STMP addition was 100g/kg, particle size of protein solution decreased to 203nm, and solubility increased to 73.5%. Furthermore, emulsifying activity and emulsifying stability increased by 0.51 times and 8 times, respectively. At the same protein concentration (1%-3% [w/w]), lutein-loaded emulsion prepared by phosphorylated SPI had higher absolute potential and smaller particle size. The phosphorylated protein emulsion at 2% concentration had the best emulsion stability after storage for 17days. PRACTICAL APPLICATION: Phosphorylation significantly improved the emulsifying properties and solubility of SPI. Phosphorylated SPI significantly improved the stability of lutein-loaded emulsion. It provides theoretical basis for the application of phosphorylated SPI as emulsifier in delivery system and broadens the development of lutein in food and medicine field.

Effect of modified soy protein isolate on dough rheological properties and noodle qualities

Soy protein isolate, soy protein hydrolysate (SPH), and texturized soy protein (TSP) were used to fortify flour nutrition, and the rheological properties of dough and qualities of noodles were determined. Soy proteins increased the peak viscosity of flour paste. Dough fortified with TSP also exhibited more solid-like behavior with the highest storage modulus, while dough fortified with SPH showed the lowest storage modulus. Soy proteins increased the cooking loss of noodles. The protein loss of SPH-W noodles was up to 32.0%, much higher than wheat noodles, 13.3%, while the protein loss of TSP-W noodles was only 14.3%. Three types of soy proteins weakened the gluten network on different levels. The larger protein molecules in TSP linked with glutenin and formed the higher molecular polymers, counterbalancing the weakening effects deriving from the interfering with the glutenin–glutenin linkages. Therefore, TSP is more suitable to utilize in noodles. Practical applications Wheat flour noodles are widely consumed in most countries, so the protein quality in noodles is critical to consumer health. The essential amino acid, lysine, is relatively deficient in wheat proteins. Soy protein is rich in lysine and could be used to fortify the nutrition of flour products. However, some negative effects of soy protein on the qualities of flour products have been observed. Therefore, we modified Soy protein isolate (SPI), hoping to increase the interaction between soy protein and wheat protein, and reduce the negative impacts of soy protein on qualities of noodles. Results showed texturized soy protein exhibited fewer negative effects on noodle qualities than SPI and soy protein hydrolysate. The results presented in this study provided us with some useful information about how to select soy proteins to fortify noodle nutrition.

Effect of a cryogenic treatment in the microstructure, functional and flow properties of soy protein isolate

In this work, the impact of cryogenic treatment of soy protein isolate (SPI) on its microstructure, functional and flow properties was evaluated. SPI was treated with 96% ethanol, freezed in liquid nitrogen, and then lyophilized to obtain the modified soy protein isolate (MSPI). To analyze the changes in the surfaces of the SPI and MSPI particles, AFM images were taken. An adsorption isotherm was performed at 25 °C, then the surface fractal dimension and specific surface area were analyzed by water adsorption isotherm at 25 °C. Functional properties such as emulsion capacity, foam, oil and water absorption, gelling and viscosity were determined. Likewise, the flow properties of powders as bulk density, tapped density, particle density, Hausner index, compressibility index and porosity were determined. MSPI showed hollows in the surface, higher roughness (Rq) and higher specific surface area than SPI. Regarding functional properties, MSPI presented higher viscosity, oil and water absorption, emulsifying and gelling capacity than SPI. MSPI powders showed lees flowability than SPI. The results suggested that the application of a cryogenic treatment in SPI changes the microstructure and impacts on the functional and flow properties of SPI, since some functional properties were improved, such as gelation, viscosity, emulsifying, adsorption and absorption capacity; and the flow properties were modified.

Effect of temperature of preheated soy protein isolate on the structure and properties of soy protein isolate heated-vitamin D3 complex.

In this paper, soy protein isolate (SPI) was preheated and combined with vitamin D3 (VD3 ) to study the protective effect of modified SPI on VD3 . The structure and properties of the SPI with heat treatment-VD3 (SPI(H)-VD3 ) complex were determined. The secondary and tertiary structure of SPI(H)-VD3 results showed that the content of α-helix decreased and the content of random coil increased, indicating that the rigid structure of the protein decreased, the flexibility increased, and the maximum fluorescence intensity wavelength was red shifted. When the heat treatment temperature was 85°C, the embedding rate of SPI(H)-VD3 composite was the highest. As the heat treatment temperature increased, the internal hydrophobic groups of SPI were exposed, and the average particle size decreased significantly. The light stability results showed that the content of VD3 in the SPI(H)-VD3 composite at a heat treatment temperature of 85°C was significantly increased compared with the unheated SPI. PRACTICAL APPLICATIONS: This article mainly discusses the structure and properties of modified soy protein isolates bound to VD3 by preheating soy protein isolates at different temperatures. It provides more possibilities for the application of VD3 in food.

Bio-based films with improved water resistance derived from soy protein isolate and stearic acid via bioconjugation

Consumed plastic packaging materials give rise to many severely negative environmental effects. As a coproduct from the soybean oil industry, soy protein isolate can be remanufactured into value-added products to replace plastics; however, the use of the soy protein isolate films developed to date has been hindered by their poor water resistance. In this work, stearic acid was applied to enhance the water resistance of the soy protein isolate films via the bioconjugation technique. The water resistance, water barrier properties, morphology, mechanical, thermal properties and mechanism of the modified films were evaluated. The successful grafting of stearic acid onto the protein via bioconjugation was confirmed by the attenuated total reflectance-Fourier transform infrared spectroscopy and X-ray diffraction measurements. As expected, stearic acid modification greatly improved the water resistance of the films. The addition of 10 wt% stearic acid contributed to a 35.3% (p < 0.05) water vapor permeability reduction, 35.8% (p < 0.05) moisture content reduction and 74.4% (p < 0.05) water absorption reduction relative to the unmodified film. Meanwhile, the water contact angle increased from 45.8° for the unmodified film to 104.6° for the modified film. Furthermore, the Young's modulus of the modified films increased, and their tensile strength and elongation at break decreased compared with those of the unmodified film. However, the decrease in the tensile strength of the obtained films was smaller than those of the physically modified soy protein isolate films. This research can help understand the effects of the chemical modification of fatty acids on soy protein isolate films, and the obtained films exhibit potential for utilization in the food packaging industry.

Improvement of freeze-thaw stability of oil-in-water emulsions prepared with modified soy protein isolates

To investigate the freeze–thaw stability of oil-in-water emulsions, we prepared soy protein isolate (SPI), SPI was enzymatically hydrolyzed by papain or by a mixture of papain and phytase, and one cycle or three cycles of freeze–thawing were performed. Their stabilities were assessed by zeta potential, particle size, microstructure, oiling off, and creaming index measurements and the structural changes were characterized by circular dichroism spectroscopy. For emulsions prepared with modified SPI samples, the freeze–thaw stability improved with increasing degree of hydrolysis, especially when the combined enzymatic treatment was performed. Furthermore, the effects of a variety of environmental factors, such as NaCl concentration, pH, and the number of freeze–thaw cycles, were considered with respect to freeze–thaw stability. Emulsions prepared with the most extensively hydrolyzed samples by papain and combined enzymatic treatment, showed a higher freeze–thaw stability than those stabilized by the SPI. In conclusion, SPI modified by papain and phytase treatment can significantly improve freeze–thaw stability and can withstand several environmental factors. The results show promise for supporting the use of SPI as an emulsifier in the food industry.

Utilization of Lignin in Biopolymeric Packaging Films.

Lignin is a byproduct of agricultural industries and only has limited applications. In this study, lignin was investigated for use in sustainable biopolymeric packaging film. Alkali lignin (AL) and lignosulfonate (LSS) were added to enzymatically modified soy protein isolate (SPI) biopolymeric film with different concentrations with the goal of improvement of film physical and functional properties. A radical scavenging activity test revealed that films containing LSS had values 28 and 6% higher than control and AL-based films, respectively; AL itself (not in films) had significantly higher radical scavenging activity than LSS. This indicates the activity of lignin is affected by interaction with SPI. The higher compatibility between LSS and enzymatically modified SPI resulted in a positive effect on surface smoothness, water absorption, and mechanical properties of LSS-based films. Films containing AL showed a high light absorption range in the UV region, and this UV-blocking ability increased with increasing level of lignin. Deconvoluted Fourier transform infrared spectra confirmed that the addition of lignin resulted in some changes in the secondary structure of the protein matrix, which were aligned with X-ray diffraction results. The addition of lignin improved tensile strength (TS) and thermal stability of films compared to the lignin-free control. This improvement in TS and thermal stability was probably a result of new intermolecular interactions between lignin and SPI. Water vapor permeability of the films containing lignin decreased to 50% of the control because lignin played a role as a filler in the matrix. On the basis of our observations, the incorporation of lignin into biopolymeric film is capable of providing additional benefits and solutions to various industries, such as food, packaging, agriculture, and pharmaceuticals.

Development of Biodegradable Textile Sizes from Soymeal: A Renewable and Cost-Effective Resource

Soymeal with high amount of solubles were used as raw materials of low-cost and biodegradable warp sizes, which have higher potential to replace non-biodegradable poly(vinyl alcohol) (PVA) for textile industry. Several protein-based materials have been studied to substitute non-biodegradable PVA sizes and remediate their environmental pollution. However, high cost and/or unsatisfied sizes properties make these protein-based sizes unattractive compared to PVA. In this research, soymeal extractant has been prepared as warp sizes and shown good sizes properties. Films elongation, adhesion, desizing efficiency and biodegradability of the developed soymeal-based sizes were higher than the sizes from physically modified soy protein isolates. Compared to the commercial PVA sizes, soymeal-based sizes showed higher adhesion and desizing efficiency but substantially lower chemical oxygen demand, indicating high potential of soymeal extractant for cleaner warp sizing. In addition, successful utilization of soymeal extractant in textile sizing will lead to value addition of agricultural byproducts.

Influence of process parameters on the bonding performance of wood adhesive based on thermally modified soy proteins

The adhesive bonding strength and water resistance of wood adhesive based on thermally modified soy protein isolate (SPI) were optimized by varying the SPI concentration, pressing temperature and pressing time. Commercial SPI was thermally modified in a vacuum chamber at 50 °C, and dispersions were prepared with SPI mass fractions of 9.09, 9.91, 10.71, 11.50, and 12.28 % in distilled water. The pH of the dispersions was adjusted to 10.0, then afterwards stirred at 50 °C for 2 h. The adhesive viscosity was measured. Effective penetration (EP) and tensile shear strength of beech wood specimens bonded under the same bonding conditions were determined (according to the European Standards EN 204 and EN 205). Adhesive with optimal SPI concentration was used for bonding at different pressing temperatures (100, 110, 120, 130, and 140 °C), whilst other bonding conditions were the same as by optimising SPI concentration. The optimal pressing temperature was determined based on tensile shear strength results. It was then used for bonding at different pressing times (6, 7, 8, 9, 10, 12, and 15 min). Optimal pressing time was determined based on tensile shear strength results. The viscosity of the adhesive increased with increased SPI concentration. The EP increased with increased viscosity and SPI mass fraction up to 11.50 % and then decreased. The adhesive with SPI mass fraction of 11.50 % showed the best water resistance. For this adhesive the optimal pressing temperature was 110 °C and optimal pressing time 10 min. The adhesive passed the durability class D3.

Improved water resistance in undecylenic acid (UA)-modified soy protein isolate (SPI)-based adhesives

Soy protein has shown potential as a renewable and environmentally friendly adhesive because of its superior performance and affordability compared with urea formaldehyde-based adhesives, but poor water resistance has limited its application as a high-performance wood adhesive comparable to phenol formaldehyde. This work focused on developing and characterizing undecylenic acid (UA)-modified soy proteins to improve their water resistance. The reaction between amine groups from protein and carboxyl groups from UA was proposed to be the main chemical pathway for grafting, which was proven by Fourier transform infrared spectroscopy (FTIR) and a ninhydrin test. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) showed that UA modification led to reduced thermal stability because of protein unfolding and decreased protein-protein cross-linkages. The increased attractive force between carbon chains of UA and protein residues resulted in higher viscosity and dynamic modulus values. Atomic force microscopy (AFM) images showed changes in protein particle size and surface properties. The wet strengths of modified soy protein adhesives were significantly improved by 35–62% compared with the control. UA with hydrophobic carbon chains and reactive carboxyl groups is an ideal bio-based modifier for soy proteins.

Effect of surface changes of soy protein materials on water resistance

The water resistance properties of unmodified soy protein isolate (SPI1) materials and modified soy protein isolate (SPI2) materials were investigated. The surface morphology and surface composition of the materials were also identified by Atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The average roughness of materials reduced from 14.362nm to 8.672nm. The N/C ratio of surface was decreased from 0.078 to 0.055, and the content of C1 reduced from 45.0% to 53.7%. Results indicate that the modification of SPI changes the surface morphology and surface composition of materials, showing higher water resistance.

Comparative study of encapsulation of vitamins with native and modified soy protein

Microencapsulation of hydrophobic (α-tocopherol) and hydrophilic (ascorbic acid) vitamins by native (non-modified) and modified soy protein isolate (SPI) was carried out using a spray-drying technique. Proteins' functional properties were modified by acylation and cationization reactions in aqueous alkaline media. The results obtained demonstrated that SPI modification resulted in decreased emulsion droplet size and viscosity. All preparations with ascorbic acid (AA) had lower viscosity and microparticle size than those with α-tocopherol (T). Moreover, grafting of fatty acid chains to SPI by acylation improved its amphiphilic character and affinity with hydrophobic substances. Thus, the microencapsulation efficiency of T was increased from 79.7% to 94.8% and the microencapsulation efficiency of AA was reduced from 91.8% to 57.3% compared to native SPI. Conversely, attachment of quaternary ammonium cationic groups to proteinic chains by cationization, increased SPI solubility and favored the AA microencapsulation. This study illustrated that an appropriate modification of SPI can improve the microencapsulation efficiency of suitable active cores.

Morphology, Structure, Miscibility, and Properties of Wholly Soy-Based Semi-interpenetrating Polymer Networks from Soy–Oil–Polyol-Based Polyurethane and Modified Soy Protein Isolate

A series of wholly soy-based semi-interpenetrating polymer networks (semi-IPN) have been successfully prepared from soy–oil–polyol-based polyurethane (S-PU) and modified soy protein isolate (M-SPI). Morphology, structure and miscibility of the semi-IPN films have been investigated by Fourier transform infrared (FT-IR) spectroscopy, film density, scanning electron microscopy (SEM), wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), and ultraviolet–visible (UV–vis) spectroscopy. The results show that the hydrogen bonds existing between S-PU chains are partially destroyed during the loading of M-SPI. In addition, the measured density of semi-IPN films are higher than the theoretically values, indicating the penetration of M-SPI into S-PU networks to bind intimately. Good miscibility between S-PU and M-SPI is confirmed by the single Tg observed in DSC and the high light transmittance under low M-SPI content (<20 wt %). Furthermore, DSC and...