Raman spectroscopic characterization of structural changes in heated whey protein isolate upon soluble complex formation with pectin at near neutral pH

Toward routine basil (Ocimum basilicum L.) callus culture analysis using non-destructive Raman spectroscopy

Here we investigated whether FT-Raman spectroscopy could be used to detect biochemical changes in small-leaved basil (Ocimum basilicum L. var. minimum Alef.) callus culture (CC). To address the effect of culture conditions and elicitor treatments, CC established on 1 mg L-1 2,4-D + 0.5 mg L-1 BAP, or 2.5 mg L-1 NAA + 0.5 mg L-1 KIN was exposed to various spectral light treatments during four weeks and compared to those grown in dark. The composition of CC was analysed both using an FT-Raman spectrometer equipped with laser 1064 nm, and spectrophotometrically. The spectral composition of light had a higher influence on the chemical composition of CC grown on NAA + KIN than on 2,4-D + BAP medium. Spectrophotometrically, no differences in the content of protein or sugar were determined in relation to the plant growth regulators applied. However, significant differences in frequencies and intensities of vibrational bands associated with proteins (S-S disulfide stretching, tyrosine, cystine, and methionine at lower spectral ranges, and amide III stretching in the higher spectral range), and carbohydrates (C-O-C skeletal mode at lower spectral ranges, and C-O-H vibrations at higher spectral ranges) within the Raman spectra were estimated and discussed. The 1525 cm-1 and 1606 cm-1 peaks with high intensities of vibration bands were identified and assigned to carotenoids and phenolics. In all treatments applied the major Raman peaks were detected at 1606, 1629, and 1633 cm-1. PCA analysis showed that CC under blue-red light and blue-red light + UVa (2,4-D + BAP) had higher content of carotenoids and ester groups, while chlorophyll a and phenolics were found in CC grown on NAA + KIN under blue-red light + UVa and blue-red light + far-red. Compared to traditional methods of analysis, which are preceded by the sample destruction before extraction and analysis, it can be concluded that the FT-Raman spectroscopy may serve as a valuable tool for the non-destructive and non-invasive identification of major biochemical changes in basil CC without any sample preparation.

Good fat vs bad fat in Milk: A molecular level Understanding of Indian cow milk using confocal Raman microscopy

Milk, a complex fluid renowned for abundance of vitamins and immune-boosting antibodies, holds a pivotal position in human nutrition. The research delves into the fundamental constituents of milk, focusing on cis-fatty acids (cis-FA), trans-fatty acids (trans-FA), and theα-helixstructure found in proteins. These constituents are instrumental in the determination of milk quality and its nutritional value. Through an analysis of Raman spectra obtained from both raw milk and its individual components, this investigation quantifies the proportional contribution ofcis-FA,trans-FA, andα-helixin diverse milk samples, thereby illuminating the disparities in milk quality. An intriguing finding of the study is the progressive increase in the percentage oftrans-FAwithin milk over time, raising concerns about its implications for milk quality and overall health. However, the research also unveils an intriguing phenomenon - heating milk can reverse the conversion oftrans-FAintocis-FA, indicating the significance of temperature and time in shaping milk's composition. This research, therefore, underscores the efficacy of Raman spectroscopy in delineating the composition of milk and its evolving nature with time and temperature, providing valuable insights pertinent to both the dairy industry and consumers' health.

The Influence of pH on the Emulsification Properties of Heated Whey Protein-Pectin Complexes

Interactions between proteins and polysaccharides could improve protein functional properties. Most studies focus on the formation of complex coacervates at pHs < pI. Much less attention has been given to the interactions at pHs > pI, especially when the mixtures are heated. The objective of this study was to investigate the emulsification properties of heated whey protein isolate (WPI) and pectin complexes formed at near neutral pHs. Heated soluble complexes (Cpxs) were formed by heating mixed WPI (3 wt% protein) and pectin (0 to 0.60 wt%) at pH 6.0, 6.5, or 7.0 at 85 °C for 30 min. Emulsions (5 wt% oil, 0.5 wt% protein, and pH 5.5) were characterized by measuring droplet size, zeta potential, rheological properties, and creaming stability. The results showed that, regardless of heating pH, Cpxs formed more stable emulsions with significantly smaller droplet sizes, higher negative charges, and less shear-thinning behavior in comparison to emulsions stabilized by heated WPI (p < 0.05). At fixed pectin concentrations, the emulsions stabilized by Cpx formed at pH 7.0 were the most stable. Increasing pectin concentrations led to a decrease in mean droplet sizes and an increase in negative charge. Maximum stability was achieved with the emulsion stabilized by Cpx formed with 0.60 wt% pectin at pH 7.0. The formation of Cpxs under proper conditions will allow for the utilization of WPI in a wider range of applications and fulfill the consumer need for clean label food products.

From lab-based to in-line: Analytical tools for the characterization of whey protein denaturation and aggregation-A review

Whey protein denaturation and aggregation have long been areas of research interest to the dairy industry, having significant implications for process performance and final product functionality and quality. As such, a significant number of analytical techniques have been developed or adapted to assess and characterize levels of whey protein denaturation and aggregation, to either maximize processing efficiency or create products with enhanced functionality (both technological and biological). This review aims to collate and critique these approaches based on their analytical principles and outline their application for the assessment of denaturation and aggregation. This review also provides insights into recent developments in process analytical technologies relating to whey protein denaturation and aggregation, whereby some of the analytical methods have been adapted to enable measurements in-line. Developments in this area will enable more live, in-process data to be generated, which will subsequently allow more adaptive processing, enabling improved product quality and processing efficiency. Along with the applicability of these techniques for the assessment of whey protein denaturation and aggregation, limitations are also presented to help assess the suitability of each analytical technique for specific areas of interest.

Structure and characterization of Tremella fuciformis polysaccharides/whey protein isolate nanoparticles for sustained release of curcumin

BACKGROUND

Whey protein isolate (WPI) nanoparticles can be used in a strategy to improve the bioavailability of curcumin (CUR) although they are generally not stable. Previous studies have indicated that Tremella fuciformis polysaccharides (TFPs) can increase the stability of WPI. This work investigated systematically the characterization and structure of TFP/WPI nanoparticles with differing CUR content.

RESULTS

The highest encapsulation efficiency of CUR was 98.8% and the highest loading content was 47.88%. The TFP-WPI-CUR with 20 mg mL-1 of CUR had the largest particle size (653.67 ± 21.50 nm) and lowest zeta potential (-38.97 ± 2.51 mV), and the capacity to retain stability across a variety of salt ion and pH conditions for 21 days. According to the findings of the structural analysis, the addition of TFPs and CUR rendered the structure of WPI amorphous, and the β-sheet was reduced. Finally, in vitro release indicated that the TFP-WPI-CUR combination could regulate the sustained release behavior of CUR.

CONCLUSION

In summary, TFP-WPI nanoparticles can be used as carriers for the delivery of CUR, and can expand applications of CUR in the functional food, dietary supplement, pharmaceutical, and beverage industries. © 2023 Society of Chemical Industry.

The level of sulfate substitution of polysaccharide regulates thermal-induced egg white protein gel properties: The characterization of gel structure and intermolecular forces

Sulfated polysaccharides exhibit great potential for regulating protein-protein interactions. In the present study, three sulfated microcrystalline cellulose (MCS) with different degrees of sulfate substitution (DSS: 0.33, 0.51, 0.61) were synthesized and the effects of DSS on the regulation of egg white protein (EWP) aggregation and gelation properties were investigated. The results found that the improvement of protein mechanical properties by MCS is closely related to the level of sulfate substitution. The higher the DSS, the more ordered protein aggregates and compact gel network formed during heating as compared to that of pure EWP. Lower DSS (0.33) shows little effect on the mechanical properties of EWP. Furthermore, all the MCSs could significantly destroy the tertiary structure of protein molecules during heating, while for the secondary structure, MCS with higher DSS (0.51 and 0.61) could effectively control the decreasing tendency of α-helix and increasing tendency of β-sheet. Hydrophobic interactions were recognized as the major intermolecular force in the compact mixed gels (EWP/MCS2 and EWP/MCS3 gels, DSS was 0.51 and 0.61, respectively). These findings provide a vital understanding of the gelling mechanism of the protein-polysaccharide system and the application of sulfated polysaccharides in protein-based food products.

Design and characterization of whey protein nanocarriers for thyme essential oil encapsulation obtained by freeze-drying

Innovative coating powders, based on whey protein concentrate (10-15 wt%) as native (WPC) or denatured protein (d-WPC), solely or in combination with alginate (0.75 wt%, AL), containing thyme essential oil, were produced using the freeze-drying technique. The impact of individual components (protein, alginate and oil) as well as the effect of heat-induced protein denaturation, was resolved regarding physicochemical, thermal and morphological properties of powders. High product yield (∼100%), particle size (223-257 nm), low moisture content (0.10-0.13%) and zeta potential (-19 to -25.6 mV) were determined for all samples. Strong antimicrobial activity of thyme oil nanocarriers against foodborne pathogens was demonstrated. Thermogravimetric analysis (TGA) indicated enhanced thermal stability of encapsulated oil. The most specific bands of structural compounds were identified in Raman spectra of the tested formulations, but principal component analysis (PCA) on recorded spectra was necessary to show the differences between carriers of different wall materials.

The complex of whey protein and pectin: Interactions, functional properties and applications in food colloidal systems - A review

This review describes the mechanism of non-covalent/covalent interaction of whey protein-pectin (WPP) complexes, including electrostatic interaction, steric hindrance, cross-linking and Maillard reaction. The interaction between whey protein and pectin determines the form of the complex in the system, i.e. co-dissolution, precipitation, separation, complex coacervation and compounding. The interaction of WPP is affected by environmental conditions and its own properties, including several factors such as pH, polymer concentration and ratio, temperature, and ionic strength. In addition, the functional properties of WPP complexes are discussed through illustrative examples. The complexes with good emulsification, heat stability, gelling properties and biological activity have promising application prospects. WPP complexes have been widely studied for application in food colloidal systems, including protein beverages, delivery systems for bioactive substances, fat substitutes and food preservation films/coatings. The understanding of the interaction and functional properties of WPP complexes provides theoretical support for the improvement and design of new food colloidal systems.

Microstructural Analysis of Whey/Soy Protein Isolate Mixed Gels Using Confocal Raman Microscopy

This work explores the potential of confocal Raman microscopy to investigate the microstructure of mixed protein gel systems. Heat-set protein gels were prepared using whey protein isolate (WPI), soy protein isolate (SPI), and mixtures thereof, with a total of five different whey-to-soy protein ratios (100, 75, 50, 25, and 0%). These were analysed using confocal Raman microscopy, and different data analysis approaches were used to maximize the amount of structural and compositional information extracted from the spectral datasets generated, including both univariate and multivariate analysis methods. Small spectral differences were found between pure WPI and SPI gels, mainly attributed to conformational differences (amide bands), but SPI exhibited considerably greater auto-fluorescence than WPI. The univariate analysis method allowed for a rapid microstructural analysis, successfully mapping the distribution of protein and water in the gels. The greater fluorescence of the capsule-like structures found in the mixed gels, compared to other regions rich in proteins, suggested that these may be enriched in soy proteins. Further analysis, using a multivariate approach, allowed us to distinguish proteins with different levels of hydration within the gels and to detect non-proteinaceous compounds. Raman microscopy proved to be particularly useful to detect the presence of residual lipids in protein gels.

Inhibition Effect of Ultrasound on the Formation of Lysinoalanine in Rapeseed Protein Isolates during pH Shift Treatment

pH shift is an effective technique for modifying functional properties of food proteins. However, it can increase lysinoalanine (LAL) content under alkali conditions, thus limiting the use of proteins. This study investigated the inhibition effect of ultrasonic parameters on LAL formation in rapeseed protein isolates (RPI) during pH shift treatment (pH-ST). Results showed that the content of LAL decreased by 49.5% and 74.1%, following the use of ultrasound (28 kHz, 40 W/L, 40 °C, and 30 min) under alkali and acidic treatment, respectively. Structural analysis showed that after ultrasonic irradiation, increased sulfhydryl groups and amino acids reduced the dehydroalanine and, thus, decreased LAL content. Particle size, secondary structure, and microstructure (SEM, AFM) analyses showed relative dispersion in protein distribution, reducing intermolecular or intramolecular cross-linking, thereby lowering the LAL content. Thus, ultrasonic-aided pH-ST may be an operational technique toward minimizing LAL formation in RPI.

The interfacial covalent bonding of whey protein hydrolysate and pectin under high temperature sterilization: Effect on emulsion stability

In this study, the effect of high-pressure steam sterilization (121 °C for 15 min) on whey protein hydrolysate-pectin solutions and emulsions was studied. The interaction and emulsification characteristics of pectin and whey protein concentrate (WPC) were evaluated from the solution system to the emulsion system. Enzymatic hydrolysis of WPC (WPH, 2 % and 8 % degree of hydrolysis) increased the covalent binding with pectin, which reduced the heat-induced aggregation of protein and improved emulsification. The thermodynamic incompatibility between WPC and pectin was not conducive to the covalent bonding under high temperature sterilization and produced serious aggregates, which also made a rapid increase in particle size (up to ∼3 μm), compared to WPH-pectin emulsion (∼ 400 nm). In addition, if emulsion was stirred during the sterilization, the creaming and protein aggregation could be avoided. By comparing low methoxy pectin (LMP) and high methoxy pectin (HMP), it was found that the whey protein-HMP complex had better emulsification stability, and the steric stabilization played a more important role in emulsion stability than the electrostatic repulsion. The changes of whey protein and pectin at the oil-water interface of the emulsion during the sterilization process may provide a reference for the sterilized bioactive ingredient delivery system.

Molecular Properties of Flammulina velutipes Polysaccharide-Whey Protein Isolate (WPI) Complexes via Noncovalent Interactions

Whey protein isolate (WPI) has a variety of nutritional benefits. The stability of WPI beverages has attracted a large amount of attention. In this study, Flammulina velutipes polysaccharides (FVPs) interacted with WPI to improve the stability via noncovalent interactions. Multiple light scattering studies showed that FVPs can improve the stability of WPI solutions, with results of radical scavenging activity assays demonstrating that the solutions of the complex had antioxidant activity. The addition of FVPs significantly altered the secondary structures of WPI, including its α-helix and random coil. The results of bio-layer interferometry (BLI) analysis indicated that FVPs interacted with the WPI, and the equilibrium dissociation constant (K_D) was calculated as 1.736 × 10^-4 M in this study. The in vitro digestibility studies showed that the FVPs protected WPI from pepsin digestion, increasing the satiety. Therefore, FVPs effectively interact with WPI through noncovalent interactions and improve the stability of WPI, with this method expected to be used in protein-enriched and functional beverages.

Marine-Inspired Enzymatic Mineralization of Dairy-Derived Whey Protein Isolate (WPI) Hydrogels for Bone Tissue Regeneration

Whey protein isolate (WPI) is a by-product from the production of cheese and Greek yoghurt comprising β-lactoglobulin (β-lg) (75%). Hydrogels can be produced from WPI solutions through heating; hydrogels can be sterilized by autoclaving. WPI hydrogels have shown cytocompatibility and ability to enhance proliferation and osteogenic differentiation of bone-forming cells. Hence, they have promise in the area of bone tissue regeneration. In contrast to commonly used ceramic minerals for bone regeneration, a major advantage of hydrogels is the ease of their modification by incorporating biologically active substances such as enzymes. Calcium carbonate (CaCO3) is the main inorganic component of the exoskeletons of marine invertebrates. Two polymorphs of CaCO3, calcite and aragonite, have shown the ability to promote bone regeneration. Other authors have reported that the addition of magnesium to inorganic phases has a beneficial effect on bone-forming cell growth. In this study, we employed a biomimetic, marine-inspired approach to mineralize WPI hydrogels with an inorganic phase consisting of CaCO3 (mainly calcite) and CaCO3 enriched with magnesium using the calcifying enzyme urease. The novelty of this study lies in both the enzymatic mineralization of WPI hydrogels and enrichment of the mineral with magnesium. Calcium was incorporated into the mineral formed to a greater extent than magnesium. Increasing the concentration of magnesium in the mineralization medium led to a reduction in the amount and crystallinity of the mineral formed. Biological studies revealed that mineralized and unmineralized hydrogels were not cytotoxic and promoted cell viability to comparable extents (approximately 74% of standard tissue culture polystyrene). The presence of magnesium in the mineral formed had no adverse effect on cell viability. In short, WPI hydrogels, both unmineralized and mineralized with CaCO3 and magnesium-enriched CaCO3, show potential as biomaterials for bone regeneration.

Formation of heated whey protein isolate-pectin complexes at pH greater than the isoelectric point with improved emulsification properties

In this study, heated whey protein isolate and pectin complexes (HCPX) formed at pH > isoelectric point (pI) were used to stabilize oil-in-water emulsions containing 5% oil and 1.5% (wt%) protein at pH 5.5. The effects of pectin concentration and heating temperature on emulsification and emulsion stabilization properties were determined. The HCPX were produced by heating mixed 3% (wt) whey protein isolate and pectin (0.1 or 0.3 wt%) at pH 6.2 and 75 or 85°C for 15 min. Aggregate sizes significantly increased with increasing heating temperature but decreased with the addition of pectin. The HCPX became more negatively charged with increasing pectin concentration; however, the effect of heating temperature was significant only at 0.1% pectin. Unheated complexes and HCPX successfully adsorbed at the oil-in-water interface and improved the emulsification properties as shown by higher negative charge and smaller droplet sizes. Despite the presence of pectin, rheological properties of the emulsions were not significantly different. All complexes showed increased emulsion stability; however, HCPX made at 85°C formed emulsions that were the most stable against creaming and heating.

Exceptional colloidal stability of acidified whey protein beverages stabilized by soybean soluble polysaccharide

Protein-rich beverages have gained significant attention in recent years. It is a challenge to produce whey protein beverages with high stability, good transparency, and a smooth mouthfeel. The polysaccharide (PS)-protein complex might help the food industry overcome these obstacles. In this study, soybean soluble polysaccharide (SSPS) and high methoxylated pectin (HMP, a traditional PS) are used, at different ratios to the protein, to improve the colloidal stability of the acidified whey protein solution. Both heated and unheated complexes were studied. SSPS-whey protein complexes have shown exceptional stabilities in all ratios while HMP-whey protein complexes revealed coacervation after 72 hr of storage. The prepared complexes exhibited comparable sizes and ζ-potentials. The SSPS-whey protein complexes were less turbid than HMP-whey protein complexes at similar PS to protein ratios. Results also show that greater repulsive interactions occurred in SSPS-whey protein complexes when compared to HMP-whey protein complexes, as examined by free thiol content and intrinsic fluorescence intensity measurements. PRACTICAL APPLICATION: It is a challenge to produce whey protein isolate (WPI) beverages with high stability, good transparency, and smooth mouthfeel. The polysaccharide (PS)-protein complex might help the food industry overcome these obstacles. We have demonstrated that soybean soluble polysaccharide (SSPS), at [SSPS]:[acWPI] ratios of 1:2 to 1:30, can significantly improve the colloidal stability of the acidified whey protein beverages. This SSPS-whey protein system could be used as a stable beverage base for a variety of beverages.

Comparison of wheat, soybean, rice, and pea protein properties for effective applications in food products

Pea and rice proteins are promising to substitute allergenic proteins, and increasingly, play important roles in the food industry because of their hypoallergenic characteristics and nutritional value. However, manufacturers generally provide limited functionality information on these proteins. Therefore, this study comprehensively compared functional properties of wheat, soybean, rice, and pea proteins for their industrial applications and illustrated correlation among various functionalities. Results showed that protein solubility (PS) was highly related to its water absorption (WA) capacity, emulsifying activity index (EAI), and emulsion stability index (ESI). The overall functionality of pea protein was close to that of soybean protein while rice protein cannot match with all other proteins. sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis indicated the composition of each protein was unique. While the deconvolution of the amide I band of the Raman spectra indicated soybean and pea proteins that shared similar features, but they were different from that of wheat and rice proteins. PRACTICAL APPLICATIONS: Due to the allergenicity of wheat and soybean proteins, food manufacturers are looking for alternative protein sources. Rice and Pea proteins are promising substitutes because of their "allergen-friendly" as well as their emergence in the food market. This study provided a comprehensive comparison of the functionality of commercially available wheat, soybean, rice, and pea proteins. The information presented in this study would be helpful to food scientists, scholars, or engineers when they develop appropriate application of various proteins in food products.

Intragastric Gelation of Heated Soy Protein Isolate-Alginate Mixtures and Its Effect on Sucrose Release

The goal of our study was to investigate the effect of alginate on in vitro gastric digestion and sucrose release of soy protein isolate (SPI) in model beverages. Model beverages containing 5% w/w SPI, 0% to 0.20% w/w alginate, and 10% w/w sucrose were prepared by heating the mixtures at 85 °C for 30 min at pH 6.0 or 7.0. Characterizations of beverages included determination of zeta potential, particle size and rheological properties. Digestion patterns and sucrose release profiles were determined during 2 hr in vitro gastric digestion using SDS-PAGE and HPLC analysis, respectively. Increasing alginate concentration led to increased negative surface charge, particle size, as well as viscosity and pseudoplastic behavior; however, no phase separation was observed. SPI beverages formed intragastric gel during in vitro gastric digestion when the formulations contained alginate or at pH 6.0 without alginate. Formation of the intragastric gel led to delayed protein digestion and release of sucrose. Higher resistance to digestion and a slower sucrose release rate were exhibited at increased alginate concentration, and to a lesser extent, at pH 6.0. This suggests that electrostatic interaction between SPI and alginate that occurred when the beverages were under gastric condition could be responsible for the intragastric gelation. These results could potentially lead to the formulation of SPI beverages with functionality to lower postprandial glycemic response.

PRACTICAL APPLICATION

The results could be used to design beverages or semi solid food products with altered digestion properties and lowered or slower glucose release.

Mechanism of Formation and Stabilization of Nanoparticles Produced by Heating Electrostatic Complexes of WPI-Dextran Conjugate and Chondroitin Sulfate

Protein conformational changes were demonstrated in biopolymer nanoparticles, and molecular forces were studied to elucidate the formation and stabilization mechanism of biopolymer nanoparticles. The biopolymer nanoparticles were prepared by heating electrostatic complexes of whey protein isolate (WPI)-dextran conjugate (WD) and chondroitin sulfate (ChS) above the denaturation temperature and near the isoelectric point of WPI. The internal characteristics of biopolymer nanoparticles were analyzed by several spectroscopic techniques. Results showed that grafted dextran significantly (p < 0.05) prevented the formation of large aggregates of WD dispersion during heat treatment. However, heat treatment slightly induced the hydrophobicity changes of the microenvironment around fluorophores of WD. ChS electrostatic interaction with WD changed the fluorescence intensity of WD regardless of heat treatment. Far-UV circular dichroism (CD) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopies confirmed that glycosylation and ionic polysaccharide did not significantly cause protein conformational changes in WD and ChS (WDC) during heat treatment. In addition, hydrophobic bonds were the major molecular force for the formation and stabilization of biopolymer nanoparticles. However, hydrogen bonds slightly influenced their formation and stabilization. Ionic bonds only promoted the formation of biopolymer nanoparticles, while disulfide bonds partly contributed to their stability. This work will be beneficial to understand protein conformational changes and molecular forces in biopolymer nanoparticles, and to prepare the stable biopolymer nanoparticles from heating electrostatic complexes of native or glycosylated protein and polysaccharide.

Stable nanoparticles prepared by heating electrostatic complexes of whey protein isolate-dextran conjugate and chondroitin sulfate

A simple and green method was developed for preparing the stable biopolymer nanoparticles with pH and salt resistance. The method involved the macromolecular crowding Maillard process and heat-induced gelation process. The conjugates of whey protein isolate (WPI) and dextran were produced by Maillard reaction. The nanoparticles were fabricated by heating electrostatic complexes of WPI-dextran conjugate and chondroitin sulfate (ChS) above the denaturation temperature and near the isoelectric point of WPI. Then, the nanoparticles were characterized by spectrophotometry, dynamic laser scattering, zeta potential, transmission electron microscopy, atomic force microscopy, and scanning electron microscopy. Results showed that the nanoparticles were stable in the pH range from 1.0 to 8.0 and in the presence of high salt concentration of 200 mM NaCl. WPI-dextran conjugate, WPI, and ChS were assembled into the nanoparticles with dextran conjugated to WPI/ChS shell and WPI/ChS core. The repulsive steric interactions, from both dextran covalently conjugated to WPI and ChS electrostatically interacted with WPI, were the major formation mechanism of the stable nanoparticles. As a nutrient model, lutein could be effectively encapsulated into the nanoparticles. Additionally, the nanoparticles exhibited a spherical shape and homogeneous size distribution regardless of lutein loading. The results suggested that the stable nanoparticles from proteins and strong polyelectrolyte polysaccharides would be used as a promising target delivery system for hydrophobic nutrients and drugs at physiological pH and salt conditions.

A review of the preparation and application of flavour and essential oils microcapsules based on complex coacervation technology

This paper briefly introduces the preparation and application of flavour and essential oils microcapsules based on complex coacervation technology. The conventional encapsulating agents of oppositely charged proteins and polysaccharides that are used for microencapsulation of flavours and essential oils are reviewed along with the recent advances in complex coacervation methods. Proteins extracted from animal-derived products (gelatin, whey proteins, silk fibroin) and from vegetables (soy proteins, pea proteins), and polysaccharides such as gum Arabic, pectin, chitosan, agar, alginate, carrageenan and sodium carboxymethyl cellulose are described in depth. In recent decades, flavour and essential oils microcapsules have found numerous potential practical applications in food, textiles, agriculturals and pharmaceuticals. In this paper, the different coating materials and their application are discussed in detail. Consequently, the information obtained allows criteria to be established for selecting a method for the preparation of microcapsules according to their advantages, limitations and behaviours as carriers of flavours and essential oils.