Preparation and characterization of whey protein isolate-chlorophyll microcapsules by spray drying: Effect of WPI ratios on the physicochemical and antioxidant properties

Natural pigments in the food industry: Enhancing stability, nutritional benefits, and gut microbiome health

Natural pigments are increasingly favored in the food industry for their vibrant colors, fewer side effects and potential health benefits compared to synthetic pigments. However, their application in food industry is hindered by their instability under harsh environmental conditions. This review evaluates current strategies aimed at enhancing the stability and bioactivity of natural pigments. Advanced physicochemical methods have shown promise in enhancing the stability of natural pigments, enabling their incorporation into food products to enhance sensory attributes, texture, and bioactive properties. Moreover, recent studies demonstrated that most natural pigments offer health benefits. Importantly, they have been found to positively influence gut microbiota, in particular their regulation of the beneficial and harmful flora of the gut microbiome, the reduction of ecological dysbiosis through changes in the composition of the gut microbiome, and the alleviation of systemic inflammation caused by a high-fat diet in mice, suggesting a beneficial role in dietary interventions.

Characteristics of pomegranate (Punica granatum L.) peel polyphenols encapsulated with whey protein isolate and β-cyclodextrin by spray-drying

Pomegranate peel polyphenols (PPPs) are recognized as promising food additives due to their diverse bioactivities; however, their application is limited by poor stability. To address this critical issue, three types of PPPs microcapsules were prepared using β-cyclodextrin (CD), whey protein isolate (WPI), and a composite material of CD-WPI through ultrasound treatment (US). Results revealed that ultrasound treatment can enhance the PPPs-wall material interaction, as evidenced by MD simulations. The encapsulation efficiency of CD-WPI-PPPs was 93.73 %, which was significantly higher than that of CD-PPPs and WPI-PPPs (p < 0.05). The degradation rate constant of CD-WPI-PPPs was reduced by 95.83 %, and its t1/2 was extended by 23-fold compared to that of unencapsulated PPPs. Furthermore, CD-WPI-PPPs exhibited greater DPPH scavenging activity and inhibited polyphenol release during oral and gastric digestion while promoting release during intestinal digestion. These outcomes were attributed to enhanced integrity and interactions between PPPs and composite materials in the microcapsules formed through ultrasound treatment, as supported by SEM images and FT-IR spectra. Consequently, the application of US in the preparation of PPPs microcapsules presents a promising strategy for developing natural nutrient additives for food applications, thereby enhancing the functional properties of food products.

Formation of chlorophyll-anionic polysaccharide complex coacervates to improve chlorophyll color stability: Thermodynamic and kinetic stability studies

Chlorophyll (Chl) is the predominant pigment in green plants that can act as a food color and possesses various functional activities. However, its instability and rapid degradation on heating compromise the sensory qualities of its products. This study aimed to enhance the heat resistance of Chl by forming complex coacervates with two negatively charged polysaccharides, sodium alginate (SA) and K-carrageenan (KC). Dynamic light scattering and scanning electron microscopy analyses confirmed the formation of coacervates between Chl and the polysaccharides, whereas Fourier-transform infrared spectroscopy revealed that hydrogen bonding and electrostatic attraction were the primary forces behind complex formation. Electron spin resonance and thermodynamic studies further revealed that these complexes bolstered the thermal stability of Chl, with a maximum improvement of 70.38 % in t1/2 and a reduction of 50.72 % in the degradation rate constant. In addition, the antioxidant capacity of Chl was enhanced up to 35 %. Therefore, this study offers a novel approach to Chl preservation and suggests a viable alternative to artificial pigments in food products.

New perspective on protein-based microcapsules as delivery vehicles for sensitive substances: A review

Sensitive substances have attracted wide attention due to their rich functional activities, such as antibiosis activities, antioxidant activities and prevent disease, etc. However, the low stability of sensitive substances limits their bioavailability and functional activities. Protein-based microcapsules can encapsulate sensitive substances to improve their adverse properties due to their good stability, strong emulsifying ability and wide source. Therefore, it is necessary to fully elaborate and summarize protein-based microcapsules to maximize their potential benefits in nutritional interventions. The focus of this review is to highlight the classification of protein-based microcapsules. In addition, the principles, advantages and disadvantages of preparation methods for protein-based microcapsules are summarized. Some novel preparation methods for protein-based microcapsules are also emphasized. Moreover, the mechanism of protein-based microcapsules that release sensitive substances in vitro is elucidated and summarized. Furthermore, the applications of protein-based microcapsules are outlined. Protein-based microcapsules can effectively encapsulate sensitive substances, which improve their bioavailability, and provide protective effects during storage and gastrointestinal digestion. In addition, microcapsules can improve the sensory quality of food and enhance its stability. The performance of protein-based microcapsules for delivering sensitive substances is influenced by factors such as protein type, the ratio between protein ratio and the other wall material, the preparation process, etc. Future research should focus on the new composite protein-based microcapsule delivery system, which can be applied to in vivo research and have synergistic effects and precise nutritional functions. In summary, protein-based microcapsules have broader research prospects in the functional foods and nutrition field.

Microencapsulation of Vitis vinifera grape pulp phenolic extract using maltodextrin and its application in gummy candy enrichment

Phenolic extract of Vitis vinifera grape pulp was prepared using ultrasonication at frequencies of 28, 40, and 28-40 kHz with a 1:10, 1:15, and 1:20 ratio of solid (grape pulp) to water. The 1:10 ratio and 40 kHz frequency were considered optimal conditions for the preparation of red grape pulp extract (RGPE). Then, RGPE was encapsulated within maltodextrin using a spray drying technique, and the produced powder was used in the gummy candy production. The results revealed that the phenolic content of the powder was almost constant during the storage time. The solubility of the powder decreased, whereas its moisture content increased during the 45-day storage period. The results of scanning electron microscopy showed that the produced microparticles had spherical shapes with a micron size. Fourier-transform infrared spectroscopy and X-ray diffraction showed that RGPE was encapsulated in the structure of maltodextrin through the formation of hydrogen bonds, considering the amorphous structure of the powder. The antioxidant properties of the microencapsulated RGPE containing gummy candy were preserved. Sensory evaluation and colorimetric values of the enriched gummy candy had acceptable results compared to the control sample. In general, microencapsulation of RGPE within maltodextrin as a carrier using the spray drying technique and its application in gummy candy enrichment could be useful.

Comparative analysis of freeze drying and spray drying methods for encapsulation of chlorophyll with maltodextrin and whey protein isolate

Chlorophyll (Chl) is a healthy green pigment that is very unstable. So, chlorophyll microcapsules were fabricated using maltodextrin and whey protein isolate as carriers and freeze-drying (FD) and spray-drying (SD) as encapsulation methods. The microcapsules obtained by the freeze-drying method (FDM) had smaller particle sizes (1.087-0.165 µm) and higher ζ-potential (-10.6 to -18.3 mV) than the spray-drying method (SDM) (3.420-0.285 µm) and (-9.5 to -10.7 mV) respectively. FTIR, XRD, and DSC studies showed that the inclusion of Chl within microcapsules and FDM had a higher melting point (150.12 °C) than SDM (125.03 °C) and Chl (115.66 °C). FD was more effective in protecting Chl from changes in pH (pH 2 to 8, Chl retention; 49.67 %-91.28 %) and light (Chl retention; 38.12 %) than SD. Therefore, due to preserving Chl and increasing its stability, FDM could be a promising approach to use as a natural food colourant.

Mechanism of Enhancing Chlorophyll Photostability through Light-Induced Chlorophyll/Phycocyanin Aggregation

Chlorophyll (Chl) is the most abundant pigment in photosynthetic plants, but it is prone to degradation during processing and storage, limiting its usage in the food industry. This study developed a technique for increasing Chl photostability by light-induced Chl/phycocyanin (PC) triple synergistic aggregation. Under continuous illumination settings, the results revealed that the Chl retention increased to 406% compared to the control. A model of Chl/PC complexes was constructed using multiligand molecular docking, and the aggregation mechanism was investigated by quantum chemistry, which demonstrated that PC could provide an ideal central hydrophobic cavity for Chl aggregates and thus further enhance the aggregation of Chl on the basis of Chl/PC complexes. The core driver of the improved photostability of Chl is photoexcitation-induced Chl aggregates. This study enriches our understanding of the interaction mechanism between PC and Chl, and we hope that this study can provide broader ideas for the development of natural pigment products.

Atomization of Cocoa Honey Using Whey Protein Isolate to Produce a Dry Formulation with Improved Shelf Life for Industrial Application

Cocoa honey, a by-product obtained during the processing of cocoa, is a juice rich in pectin, organic acids, minerals and phenolic compounds with antioxidant properties. Fresh cocoa honey is quickly fermented due to its high content of reducing sugars, such as fructose and glucose, which limits its shelf life. Currently, cocoa honey is only commercialized in frozen form, as logistical challenges prevent the wide distribution or export of this by-product for applications in the market of sweets, jellies, beverages, confectionery, and nutraceutical foods among others. Spray-drying technology is a viable prospect for the large-scale stabilization of products such as cocoa honey, with less heat exposure compared to other conventional drying methods. This work aimed to evaluate the efficacy of drying adjuvants for a rapid removal of the water present in cocoa honey via atomization, since this process minimizes the effects of glass transition temperature (Tg) related to materials with high sugar contents. Physical parameters such as the moisture content, hygroscopicity, particle size, and yield of the products obtained were determined. Cocoa honey presented 85.3 ± 0.20 g/100 g of moisture. The formulations successfully decreased moisture content, which was lower than 11.72 ± 0.08 g/100 g in the formulations. Water activity ranged between 0.1464 ± 0.0043 and 0.1562 ± 0.029, with no significant difference between the formulations. The hygroscopicity of cocoa honey powders ranged from 29.29 to 29.87 g of water/100 g of cocoa honey. The combination of 20% maltodextrin and 1% whey protein isolate (WPI) led to the best yield, resulting in a free-flowing powder as the final product. On the other hand, the formulation composed of maltodextrin and whey protein isolate in the ratio of 29:1, respectively, led to the most stable product, with less loss of phenolic compounds during the drying process (6.04%). Regarding particle diameter, 90% of the accumulated distribution did not exceed 57 μm. The greatest dispersion of particles occurs in the Ma20W10 formulation with a span of 2.72, inferring greater variation in size between small (7.01 ± 0.06 μm), medium (18.25 ± 0.37 μm), and large (56.65 ± 1.17 μm) particles. The use of whey protein isolate as an adjuvant proved to be an efficient drying process in the production of cocoa honey powder, and was also advantageous for enriching the nutritional content of the final product due to its protein origin. Furthermore, the combination of spray-drying technology and the use of whey protein isolate as adjuvant led to a free-flowing cocoa honey powder with an adequate particle size and benefits in terms of shelf-life extension, providing new opportunities for the commercialization of cocoa honey as an ingredient for the food industry, with benefits for the circular economy.

Inulin-whey protein as efficient vehicle carrier system for chlorophyll: Optimization, characterization, and functional food application

Natural chlorophylls mostly found in vegetables such as spinach (Spinacia oleracea) could be employed as a possible substitute for synthetic colorants because of their intense green properties. However, the stability of natural chlorophyll is a major challenge to its utilization in the food industry. In this study, spray drying as an encapsulation technique was used to improve the stability of natural chlorophyll. Box-Behnken design was utilized to optimize the spray drying conditions for chlorophyll. Optimum conditions were given as inlet temperature, 132°C; inulin-to-whey protein isolate ratio, 61%:39%; pump rate, 25%, resulting in 92.3% encapsulation efficiency, 69.4% solubility, and -13.5 mV zeta potential at a desirability level of 0.901. The particle size, Carr index, bulk and tapped density, polydispersity index, and color showed satisfactory results. Crystallinity, endothermic peak melting temperature, and the enthalpy of chlorophyll-loaded microcapsules increased when compared to the blank microcapsules suggesting decreased hygroscopicity and enhanced thermal stability. In addition, the suitability of fabricated microcapsules using yogurt as a food model was assessed. Yogurt incorporated with chlorophyll-loaded microcapsules showed no significant pH modification with better apparent viscosity than control and sodium copper chlorophyllin (SCC) yogurt after 9 days of refrigerated storage. Based on the studied responses, the spray drying process could be optimized to achieve optimal output and product quality. PRACTICAL APPLICATION: Spray drying is a cheap and convenient approach for microencapsulating bioactive compounds such as chlorophyll. However, the physico-chemical and functional properties of the spray-dried microcapsules are influenced by operating conditions, such as inlet temperature, type and concentration of wall materials, and feed flow rate. Therefore, to maximize and obtain a superior quality of the final product, there is a need to optimize the spray drying process. The Box-Behnken design employed in this study could be utilized as an appropriate technique to design, enhance, and develop process parameters for the fabrication and better retention of the physico-chemical properties of spray-dried chlorophyll microcapsules.

Wall Materials for Encapsulating Bioactive Compounds via Spray-Drying: A Review

Spray-drying is a continuous encapsulation method that effectively preserves, stabilizes, and retards the degradation of bioactive compounds by encapsulating them within a wall material. The resulting capsules exhibit diverse characteristics influenced by factors such as operating conditions (e.g., air temperature and feed rate) and the interactions between the bioactive compounds and the wall material. This review aims to compile recent research (within the past 5 years) on spray-drying for bioactive compound encapsulation, emphasizing the significance of wall materials in spray-drying and their impact on encapsulation yield, efficiency, and capsule morphology.

Effect of ultrasonication on emulsion formulation, encapsulation efficiency, and oxidative stability of spray dried chia seed oil

Present study was conducted to develop a stable chia oil emulsion using an ultrasound emulsification technique. Whey protein concentrate, gum Arabic, and xanthan gum stabilized layer by layer chia oil emulsion was developed using an electrostatic deposition. Single-layer and multilayer emulsion of chia oil was developed and their stability is compared. Developed emulsions were characterized by viscosity, stability, surface charge, and droplet size. Layer-by-layer emulsion showed the highest stability (98%) among all the formulations developed. Formulated single-layer and double-layer emulsions were spray dried and the respective powders were characterized for bulk density, tapped density, Hausner ratio, Carr's index, moisture content, color values, encapsulation efficiency, peroxide value, XRD, and SEM. Multilayer emulsion-based powder showed better flowability properties. The encapsulation efficiency of multilayer microparticles was found to be 93% with the lowest peroxide value of 1.08 mEq O2/kg fat. XRD diffractogram of the developed microparticles revealed amorphous nature. The developed ultrasound layer-by-layer emulsification technique is an efficient technique for developing chia oil-loaded microparticles.

The chromogenic mechanism of natural pigments and the methods and techniques to improve their stability: A systematic review

Pigments have become a very important part of food research, not only adding sensory properties to food, but also providing functional properties to the food system. In this paper, we review the source, structure, modification, encapsulation and current status of the three main types of natural pigments that have been studied in recent years: polyphenolic flavonoids, tetraterpenoids and betaines. By examining the modification of pigment, the improvement of their stability and the impact of new food processing methods on the pigments, a deeper understanding of the properties and applications of the three pigments is gained, the paper reviews the research status of pigments in order to promote their further research and provide new innovations and ideas for future research in this field.

Protection of Mono and Polyunsaturated Fatty Acids from Grapeseed Oil by Spray Drying Using Green Biopolymers as Wall Material

One of the most common ways to protect oils is microencapsulation, which includes the use of encapsulating agents. Due to the environmental problems facing humanity, this study seeks to combine green biopolymers (microcrystalline cellulose and whey protein isolate) that function as encapsulating agents for grapeseed oil. Grapeseed oil that is obtained from agro-industrial waste has shown health benefits, including cardioprotective, anticancer, antimicrobial, and anti-inflammatory properties. These health benefits have been mainly associated with monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids. In this sense, it has been observed that grapeseed oil can be easily modified by environmental factors such as oxygen, high temperatures, and light, showing the instability and easy degradation of grapeseed oil. In this study, grapeseed oil was encapsulated using the spray-drying technique to conserve its lipidic profile. Powder recovery of the grapeseed oil microcapsules ranged from 65% to 70%. The encapsulation efficiency of the microcapsules varied between 80% and 85%. The FTIR analysis showed chemical interactions that demonstrate chemisorption between the grapeseed oil and the encapsulating material, while the SEM micrographs showed a correct encapsulation in a spherical shape. Gas chromatography showed that the lipid profile of grapeseed oil is preserved thanks to microencapsulation. Release tests showed 80% desorption within the first three hours at pH 5.8. Overall, whey protein and microcrystalline cellulose could be used as a wall material to protect grapeseed oil with the potential application of controlled delivery of fatty acids microcapsules.

The Physicochemical Properties and Antioxidant Activity of Spirulina (Artrhospira platensis) Chlorophylls Microencapsulated in Different Ratios of Gum Arabic and Whey Protein Isolate

Spirulina (Artrhospira platensis) is rich in chlorophylls (CH) and is used as a potential natural additive in the food industry. In this study, the CH content was extracted from spirulina powder after ultrasound treatment. Microcapsules were then prepared at different ratios of gum Arabic (GA) and whey protein isolate (WPI) through freeze-drying to improve the chemical stability of CH. As a result, a* and C* values of the microcapsules prepared from GA:WPI ratios (3:7) were −8.94 ± 0.05 and 15.44 ± 0.08, respectively. The GA fraction increased from 1 to 9, and encapsulation efficiency (EE) of microcapsules also increased by 9.62%. Moreover, the absorption peaks of CH at 2927 and 1626 cm⁻¹ in microcapsules emerged as a redshift detected by FT-IR. From SEM images, the morphology of microcapsules changed from broken glassy to irregular porous flake-like structures when the GA ratio increased. In addition, the coated microcapsules (GA:WPI = 3:7) showed the highest DPPH free radical scavenging activity (SA_DPPH) (56.38 ± 0.19) due to low moisture content and better chemical stability through thermogravimetric analysis (TGA). Conclusively, GA and WPI coacervates as the wall material may improve the stability of CH extracted from spirulina.

The physicochemical properties and the release of sodium caseinate/ polysaccharide gum chlorophyll multiple-layer particles by rotary side-spray fluid bed technology

Multiple-layer coating technology has widely applied to the quality modification of bioactive ingredients nowadays. This research used a rotary side-spray fluid bed to manufacture chlorophyll multiple-layer particles to adjust control release characteristics. The chlorophyll extracts were coated with sodium alginate (A1) and sodium caseinate (CA1) as the primary layer on sugar spheres and the product yield was 96.98 and 96.71%, respectively. The content of chlorophyll a and b (μg/g) were 41.04 and 13.20 in A1, 47.40 and 13.68 in CA1. The Fourier-transform infrared spectroscopy confirmed the bonding change and increase stability. The CA1 was coated with sodium alginate (CA-A), sodium carboxymethylcellulose (CA-C) and xanthan gum (CA-X) as the secondary layer, which can increase coated integrity, shell strength and thermal stability. The simulated gastrointestinal fluid showed 30.11% release in the stomach and 94.27% in the intestine, which improved release control characteristics. Increased retention rate and color stability in the storage test.

Stability and bioavailability of protein matrix-encapsulated astaxanthin ester microcapsules

BACKGROUND

Astaxanthin ester derived from Haematococcus pluvialis is often used as a functional and nutritional ingredient in foods. However, its utilization is currently limited as a result of its chemical instability and low bioavailability. Food matrix microcapsules are becoming increasingly popular because of their safety and high encapsulation efficiency. In the present study, the effect of protein matrixes on the properties of microcapsules was evaluated.

RESULTS

We investigated the effects of storage on astaxanthin ester microcapsules and the corresponding rehydration solution at 40 °C under a nitrogen atmosphere, as well as in darkness. The results showed that the stability of products prepared based on whey protein (WP) and corn-gluten was superior to that of products prepared based on lactoferrin, soy protein and sodium caseinate. The bioavailability of astaxanthin ester microcapsules encapsulated with different proteins and examined by means of astaxanthin concentrations in the serum and liver after oral administration was compared. All five protein wall materials could significantly improve the bioavailability of astaxanthin ester. The microcapsules prepared based on WP had the highest bioavailability, with a value of 10.69 ± 0.75 μg·h mL^-1 , which was 3.15 times higher compared to that of the control group.

CONCLUSION

The results of the present study showed that protein encapsulation, especially WP encapsulation, could effectively improve the stability, water solubility and bioavailability of astaxanthin esters. Thus, WP can be used as the main wall material in delivery systems. © 2021 Society of Chemical Industry.

Co-microencapsulation: a promising multi-approach technique for enhancement of functional properties

Co-microencapsulation is a growing technique in the food industry because it is a technique that, under the same fundamentals of microencapsulation, allows the generation of microcapsules with a longer shelf life, using a smaller number of encapsulating materials and a smaller amount of active compounds, while having a greater beneficial activity. This responds to consumer demand for higher quality foods that limit the use of ingredients with low nutritional content and provide beneficial health effects, such as probiotics, prebiotics, vitamins, fatty acids, and compounds with antioxidant activity. The combination of two or more active compounds that achieve a synergy between them and between the encapsulating materials offers an advantage over the well-known microencapsulation. Among the main active compounds used in this process are probiotics, prebiotics, fatty acids, and polyphenols, the main combination being that of probiotics with one of the other active compounds that enhances their benefits. The present review discusses the advantages and disadvantages of the different encapsulating materials and techniques used to obtain co-microencapsulants, where the main result is a higher survival of probiotics, higher stability of the active compounds and a more controlled release, which can lead to the generation of new foods, food supplements, or therapeutic foods for the treatment of common ailments.

Improvement of betalains stability extracted from red dragon fruit peel by ultrasound-assisted microencapsulation with maltodextrin

Natural betalains can be potential food additives because of their antioxidant activities, but they have poor thermal stability. In this study, betalains were extracted from red dragon fruit peel, and then encapsulated with maltodextrin by ultrasound method to increase the physicochemical properties of betalains microcapsules. The encapsulation efficiency of the betalains was above 79%, and the particle size and Zeta potential values were 275.46 nm and -29.01 mV, respectively. Compared to the control sample, onset temperature and DPPH free radical scavenging of betalains microcapsules under the modest ultrasound treatment (200 W, 5 min) was increased by 1.6 °C and 12.24%, respectively. This increase could be due to the ability of ultrasonification to create interactions between maltodextrin and betalains (as evidenced by FT-IR). Therefore, modest ultrasound treatment can be used for microcapsulation to improve the stability of betalains, and then expand the application of betalains in heat processed food field.

Development of an Ultrasonic-Assisted Extraction Technique for the Extraction of Natural Coloring Substance Chlorophyll from Leaves of Carica papaya

Beautiful green leaves of Papaya are the rich source of Chlorophyll. Green color of chlorophyll has been used for a very long time as a natural colorant. Carica papaya has been considered as a good example and reasonable source of natural phytochemicals, which makes it suitable to color the food items and beverages. The aim of the present investigation is to develop the process of ultrasonic extraction in combination with solid phase extraction (SPE) to extract out chlorophyll with high yield as well as high degree of clarity. Newly customized ultrasonic-assisted extraction technique for the extraction of chlorophyll from Carica papaya leaves is optimized by taking different parameters like time, temperature, solvents concentrations, and raw material under consideration. Furthermore, the extract was purified by means of SPE and examined by using UV-Vis spectrophotometer. The highest yield of chlorophyll (dye) extract was found as 40% in solvent solution having 80 mL of ethanol and 20 mL of water with 5 minutes of extraction time, 35°C of temperature, and 1 grams of raw material in the sonication bath. Furthermore, the SPE purified sample was characterized by means of the UV-Vis spectrophotometer and here the total chlorophyll content was 34 mg/g, including chlorophyll a with a concentration of 14.1246 mg/g and chlorophyll b with concentration of 19.845 mg/g respectively. Consequently, sonication method can be suggested as a good method to get better concentration of chlorophyll.

Modification of soy protein isolate by Maillard reaction and its application in microencapsulation of Limosilactobacillusreuteri

Limosilactobacillusreuteri was encapsulated using Maillard-reaction-products (MRPs) of soy protein isolate (SPI) and α-lactose monohydrate by freeze-drying. The mixed solution of SPI and α-lactose monohydrate was placed in a water bath at 89°C for 160 min for Maillard reaction, and then freeze-dried to obtain MRPs. The effects of Maillard reaction on functional characteristics of MRPs and the properties of MRPs-microcapsules were studied. SDS-PAGE indicated that SPI subunit reacted with lactose to form a polymer, and the band of MRPs disappeared around the molecular weights of 33, 40, 63, and 100 kDa. Compared with SPI, the emulsion stability, emulsion activity, foaming capacity, foam stability, and gel strength of MRPs were increased by 259%, 55.71%, 82.32%, 58.53%, and 3266%, respectively. The results of Fourier transform infrared spectroscopy, circular dichroism spectroscopy, and scanning electron micrographs confirmed that the protein structure also changed significantly. Then, MRPs were used as wall material to prepare L. reuteri microcapsules. Physical properties and viable counts of L. reuteri during the simulated gastrointestinal digestion and storage period were determined. The particle size of MRPs-microcapsules (68 μm) was smaller than that of SPI-microcapsules (91 μm). The viable counts of L. reuteri in simulated gastrointestinal digestion and after storage for 30 days were improved. The modifications with Maillard reaction can improve emulsification, foaming, and gel strength of SPI, and MRPs could be used as a new type of wall material in the production of L. reuteri microcapsules.

Exploring the interactions between Lactobacillus rhamnosus GG and whey protein isolate for preservation of the viability of bacteria through spray drying

Protective agents used in spray drying protect the activity of lactic acid bacteria (LAB) by stabilizing the subcellular structures, constituting a protective layer at the cellular surface, or having mild drying kinetics. The effects of a reputed protectant, whey protein isolate (WPI), on Lactobacillus rhamnosus GG (LGG) were examined by exposing the cells to WPI solution to induce protein adsorption at the cellular surface prior to spray drying. WPI-treated LGG demonstrated enhanced thermotolerance with cell survival increased by 1.64 log after heat treatment. The survival after spray drying was significantly decreased from 45.75% to 8.6% and from 32.96% to 10.44%, when the WPI-treated cells were resuspended in trehalose solution or reconstituted skimmed milk as protectant, respectively, associated with decreased growth capability and metabolic activity. The contact with WPI appeared to stimulate the cellular response of LGG. With well-maintained cell viability and intact cellular membrane, the metabolic activity of WPI-treated LGG was decreased, and subsequent resuspension of the cells in trehalose solution led to a reduction in the stability of the cellular surface charge. The WPI-treated cells showed marginally increased surface roughness, indicating possible WPI attachment, but there was no thick protein coverage at the cellular surface and the size distribution of cells was unaffected. It was proposed that the enhanced thermotolerance and the decreased survival of spray-dried LGG could be linked to the cellular response toward WPI and protectant media, which may vary among individual LAB strains. Modulating the strain-specific interactions between the LAB cells and the protectant constituents could be crucial to maximizing cell viability retention after spray drying.

Production and application of freeze dried biocomposite coating powders from sunflower oil and soy protein or whey protein isolates

Innovative biocomposite coating powders based on soy protein isolate or whey protein isolate, both containing sunflower oil (SO) were fabricated by freeze drying technique. The influences of concentration of SO and using different protein isolate types on the physicochemical, thermal and morphological properties of the powders were investigated. The Fourier transform infrared spectroscopy and thermal analysis revealed that SO interacted with protein isolates through hydrogen bonding resulted a strong network structure of the powders. It was found that amorphous structure and morphology of the powders was not significantly influenced by oil addition. Moisture content and water activity values of SPI powders were found higher than those of WPI. All powders were wettable, and solubility values were in the range of 91-99%. Preservative-free powders were reconstituted and applied to coat sliced cakes, a bakery product. Coating application showed effective protection on textural structure of cake by high moisture preservation ability.

Carotenoids and Chlorophylls as Antioxidants

Chlorophylls and carotenoids are natural pigments that are present in our daily diet, especially with the increasing tendency towards more natural and healthy behaviors among consumers. As disturbed antioxidant homeostasis capacities seem to be implicated in the progress of different pathologies, the antioxidant properties of both groups of lipophilic compounds have been studied. The objective of this review was to analyze the state-of-the-art advances in this field. We conducted a systematic bibliographic search (Web of Science™ and Scopus®), followed by a comprehensive and critical description of the results, with special emphasis on highly cited and more recently published research. In addition to an evaluative description of the methodologies, this review discussed different approaches used to obtain a physiological perspective, from in vitro studies to in vivo assays using oxidative biomarkers. From a chemical viewpoint, many studies have demonstrated how a pigment's structure influences its antioxidant response and the underlying mechanisms. The major outcome is that this knowledge is essential for interpreting new data in a metabolic networks context in the search for more direct applications to health. A promising era is coming where the term "antioxidant" is understood in terms of its broadest significance.