Spray-dried and freeze-dried protein-spinach particles; effect of drying technique and protein type on the bioaccessibility of carotenoids, chlorophylls, and phenolics

Process Optimization of Fluidized Bed Drying for Water Spinach: Evaluating the Effect of Blanching Through RSM and ANN Models

The quality of the dried leafy vegetables, such as water spinach (Ipomoea aquatica), has been found to be significantly affected by the drying process in terms of moisture content and retention of important nutrients, namely vitamin C and β-carotene. There is great potential for fluidized bed drying to be applied for leafy vegetables in optimizing process parameters for maximum nutrient retention since it has not been researched. This work investigated the effect of temperature, drying time, and bed thickness on the nutritional quality of blanched and unblanched water spinach samples. In the present study, the fluidized bed drying process has been designed and optimized using a Central Composite Design (CCD) and Response Surface Methodology (RSM). For this study, both RSM and artificial neural network (ANN) predictive models are developed for further comparison. Using a multiobjective desirability function, the best-optimized response was given from the experimental model for the responses of moisture content, vitamin C, and β-carotene retention. Appropriate statistical metrics are applied, for example, AARD (Absolute Average Relative Deviation), MRD (Mean Relative Deviation), MSE (Mean Squared Error), and R 2 (Coefficient of Determination), which helped in model comparison during the study. It was observed from the experiment that all the response variables are significantly affected by drying temperature, time, and bed thickness. Variation of bed thickness in the blanched samples affected > 16% in moisture content attainment compared to unblanched samples, and vitamin C content exhibited a variation of more than 25% due to changes in bed thickness for blanched samples on the contrary. RSM has shown a better performance than ANN in its precision and prediction power. The optimized drying conditions came out to be 60°C as the drying temperature, 7.19 min as the drying time, and 5.12 cm as the bed thickness, which resulted in 2.95% of moisture content, 5.99 mg/100 g vitamin C, and 139.16 μg/g of β-carotene. The close alignment between predicted and experimental values confirms the suitability of the optimized conditions for industrial-scale drying of leafy vegetables.

Metabolomics insights into the protective molecular mechanism of Vaccinium myrtillus against oxidative stress in intestinal cells

Blueberry (Vaccinium myrtillus L.) is a rich source of secondary metabolites known for their potent antioxidant, anti-inflammatory, and cytoprotective properties. These compounds are essential in neutralizing reactive oxygen species (ROS), which are implicated in oxidative stress-related diseases. In this study, we induced oxidative stress in IEC-6 small intestine cells using hydrogen peroxide (H2O2), creating a cellular model to investigate the biochemical response. The obtained results showed that a blueberry extract (BLUBE) significantly exhibited strong antioxidant capacity, as evidenced by DPPH, FRAP and ABTS in vitro tests. Additionally, BLUBE effectively inhibited the release of reactive species in cells and enhanced cytoprotective response, as indicated by improved wound healing and clonogenic potential reduction of stress fibers rearrangement and apoptosis. Metabolomic analysis, specifically High-Resolution Mass Spectrometry (HR-MS), was employed to elucidate the metabolic alterations associated with the protective activity of BLUBE against oxidative stress in IEC-6 cells. Chemometric approaches were applied to preprocess the data, explore variability, and identify systematic biases, ensuring the removal of batch effects and other experimental artifacts. A Partial Least Squares Discriminant Analysis classification model confirmed clear group stratifications with high accuracy (98.75 ± 2.31%), sensitivity, and specificity, aiding in the identification of significant metabolites for pathway enrichment analysis. Key metabolic pathways, including sphingolipid metabolism, taurine and hypotaurine metabolism, glycerophospholipid metabolism, and cysteine and methionine metabolism, were significantly modulated, supporting the biochemical basis of BLUBE's protective effects. In fact, BLUBE was able to partially reverse the downregulation of these pathways, effectively reducing oxidative stress and promoting cell survival. This study highlights the power of HR-MS-based metabolomics in uncovering the mechanisms of nutraceuticals and emphasizes the potential of BLUBE as a protective agent for oxidative stress-related diseases. It also underscores the growing significance of metabolomics in the food and pharmaceutical industries.

Valorization of okra waste: Microencapsulation of okra flower polyphenol-rich extract with maltodextrin and gum Arabic by freeze drying, spray drying, and microwave drying

Okra (Abelmoschus esculentus (L.) (Moench.)) flowers are under valorized byproducts of okra production. They are a rich source of nutrients and have shown strong antioxidant activity. This study has optimized the extraction of phenolics, flavonoids and antioxidants from okra flowers by response surface methodology. The effect of extraction temperature (26.4-93.6°C), time (6-75 min), and solvent volume (18-102 mL) was evaluated. The optimum extraction conditions were determined as 80°C, solvent volume of 85 mL, and extraction time of 61 min. The extract prepared at optimum conditions was then microencapsulated with maltodextrin, gum Arabic, and a combination of both (1:1) using different drying techniques (freeze drying, spray drying, and microwave drying). The physicochemical properties of the resulting products were analyzed and characterized using differential scanning calorimetry, scanning electron microscopy, and infrared spectroscopy. The drying method impacted the polyphenol levels and bioaccessibility, physical powder properties, and surface characteristics of the resultant product, while the microencapsulation method mainly impacted the polyphenol content, glass transition temperature, and polyphenol bioaccessibility to a lesser extent. Microencapsulation with maltodextrin resulted in powders with significantly higher quercetin-3-glucoside (90-100 mg/kg), and epicatechin (480-580 mg/kg) content. The combination of freeze drying with maltodextrin microencapsulation provided the highest content of various polyphenols and bioaccessibility, as well as a very low water activity (0.038 ± 0.000). However, the powder was less free-flowing compared to microwave drying and tended to have a lower solubility. Consequently, the optimum drying and microencapsulation method will be a compromise between the different importance afforded to each of the aforementioned parameters.

Fermentation of American elderberry juice yields functional phytochemicals for spray dried protein-polyphenol ingredients

American elderberry juice (EBJ) and fermented elderberry juice (EBF) were spray dried using two different carriers: S. cerevisiae yeast (SC), used for juice fermentation and as encapsulating agent, and pea protein, to produce protein-polyphenol ingredients. The spray drying (SD) performance (solids recovery, SR; phenolic retention, PR) and quality attributes (physicochemical and functional properties, phytochemical content and bioaccessibility after in vitro digestion) of eight treatments of spray dried elderberry particles were determined. The total phenolic content (TPC) of EBJ (4476 ± 169 mg GAE/L) increased by 27 % after fermentation (EBF: 5706 ± 199 mg GAE/L). The SD performance of EBF (SR > 50 %; PR 55.7-63.9 %) was significantly higher (p < 0.05) compared to EBJ (SR < 50 %; PR 28.6-42.8 %). Stable (aw < 0.3) protein-polyphenol particles, with pH-dependent solubility that increased as pH went from 4 to 10, were produced. The TPC of EBF-derived particles (26.2-28.7 mg GAE/g) was 22-31 % higher than EBJ-derived particles (20.4-21.9 mg GAE/g) and anthocyanins were the major phenolic group detected. An increase in nearly all phenolic metabolite concentrations was observed after fermentation, and an additional increment was observed after spray drying. Phenolic bioaccessibility improved (17-25 % higher) after S. cerevisiae fermentation and when using SC as the drying carrier compared to phenolics source (EBJ or EBF). Overall, here we show a sensible strategy to produce protein-polyphenol particles with better SD performance and enhanced phytochemical content and profile. Our fermentation and spray drying strategy provides practical and efficient means to produce functional fruit ingredients for the emerging clean-label, health-oriented market.

Betalain-Chickpea Protein Particles Produced by Freeze Drying and Spray Drying: Physicochemical Aspects, Storage Stability, and In Vitro Digestion

Beetroots are one of the primary sources of betalains, nitrogenous pigments with anti-inflammatory and antioxidant properties. However, due to their chemical instability, betalains have limited use in food applications. This work investigated whether betalains encapsulated in chickpea protein could be stabilized and delivered in a shelf-stable format. Freeze-dried (CB-FD) and spray-dried (CB-SD) protein-betalain particles encapsulated in chickpea protein isolate (6% w/v) were prepared. The encapsulation method affected particles' morphology, water activity, hygroscopicity, solubility, and color. Particles captured total betalains of 9.30 ± 0.61 and 4.40 ± 0.92 mg/g for CB-SD and CB-FD, respectively. LC-MS identified 12 betacyanins and 6 betaxanthins. The stability of betalains revealed that encapsulation efficiently preserved betalain integrity of over 6 weeks of storage at 4, 22, and 40 °C compared to dry beetroot extract. CB-SD particles were stable with no significant changes, while CB-FD showed slight degradation after 4 weeks due to increased Aw. Antioxidant activity correlated well with betalain concentration. In vitro digestion resulted in only 25% bioaccessibility of betacyanins, while betaxanthins were more stable with 100% recovery. Encapsulation with chickpea protein isolate is an efficient and straightforward strategy for expanding and diversifying applications of phytochemical-rich beetroot extracts for the food industry.

Spinacia oleracea L. Baby Leaves as a Source of Bioactive Principles: The Chemical Profiling of Eco-Sustainable Extracts by Using LC-ESI/HRMS- and 1H NMR-Based Metabolomics

Spinacia oleracea L. cultivar platypus leaves are identified as a functional food due to their nutrient composition which promotes health beyond basic nutrition. Considering the increasing use of food supplements, S. oleracea baby leaves have been extracted by maceration, solid-liquid dynamic extraction (SLDE)-Naviglio, and ultrasound-assisted extraction (UAE) using EtOH and EtOH:H2O mixtures. The analysis of the extracts by using LC-ESI/HRMSMS revealed 42 compounds (flavonoids, polar lipid derivatives, and 20-hydroxyecdysone), along with primary metabolites, detected by NMR analysis. A principal component analysis (PCA) of LC-ESI/HRMS and NMR data was performed, revealing how 20-hydroxyecdysone and flavonoids, the specialized metabolites mainly responsible for the biological activity of S. oleracea leaves, occurred in the highest amount in the EtOH and EtOH:H2O (70:30, v/v) extracts obtained by SLDE-Naviglio extraction. 20-hydroxyecdysone was also quantified in all the extracts via LC-ESI/QTrap/MS/MS using the Multiple Reaction Monitoring (MRM) method. The EtOH extracts obtained by SLDE-Naviglio and maceration showed the highest content (82.16 and 81.27 mg/g extract, respectively). The total phenolic content (118.35-206.60 mg GAE/g), the flavonoid content (10.90-41.05 mg rutin/g), and the Trolox Equivalent Antioxidant Capacity (TEAC) (1.63-2.05 mM) of the extracts were determined. The EtOH:H2O (70:30, v/v) extract analyzed by using SLDE-Naviglio showed the highest phenolic and flavonoid content and radical scavenging activity.

Colloidal and interfacial properties of spray dried pulse protein-blueberry polyphenol particles in model dispersion systems

The phytochemical composition and physicochemical attributes of polyphenol-enriched protein particle ingredients produced with pulse proteins (e.g. chickpea protein, pea protein, and a chickpea-pea protein blend) and polyphenols recovered from wild blueberry pomace were investigated for colloidal and interfacial properties. Anthocyanins were the major polyphenol fraction (27.74-36.47 mg C3G/g) of these polyphenol-rich particles (44.95-62.08 mg GAE/g). Dispersions of pea protein-polyphenol particles showed a superior phase stability before and after heat treatment compared to the chickpea pea protein-polyphenol system. This observation was independent of the added amount of NaCl in the dispersion. In general, at quasi equilibrium state, pulse protein-polyphenol particles and parental pulse protein ingredients showed similar oil-water interfacial tension. However, pea protein-polyphenol particles demonstrated a reduced diffusion-driven oil-water interfacial adsorption rate constant compared to the parental pea protein ingredient. Overall, the obtained results suggest application potential of pea protein-polyphenol particles as a functional food/beverage ingredient.

Effect of Pulsed Electric Fields on the Shelf Stability and Sensory Acceptability of Osmotically Dehydrated Spinach: A Mathematical Modeling Approach

This study focused on the osmotic dehydration (OD) of ready-to-eat spinach leaves combined with the pulsed electric field (PEF) pre-treatment. Untreated and PEF-treated (0.6 kV/cm, 0-200 pulses) spinach leaves were osmotically dehydrated at room temperature for up to 120 min. The application of PEF (0.6 kV/20 pulses) prior to OD (60% glycerol, 25 °C, 60 min) lowered water activity (aw = 0.891) while achieving satisfactory product acceptability (total sensory hedonic scoring of 8). During the storage of the product (at 4, 8, 12, and 20 °C for up to 30 d), a significant reduction in total microbial count evolution was observed (9.7 logCFU/g for the untreated samples vs. 5.1 logCFU/g for the PEF-OD-treated samples after 13 d of storage at 4 °C). The selection of these PEF and OD treatment conditions enabled the extension of the product shelf life by up to 33 d under chilled storage. Osmotically treated spinach could find application in ready-to-eat salad products with an extended shelf life, which is currently not possible due to the high perishability of the specific plant tissue.

Spray dried acerola (Malpighia emarginata DC) juice particles to produce phytochemical-rich starch-based edible films

This study aimed to produce spray dried acerola juice microparticles with different protein carriers to be incorporated into edible starch films. The microparticles were evaluated for solids recovery, polyphenol retention, solubility, hygroscopicity, particle size distribution, X-ray diffraction, phytochemical compounds and antioxidant activity. Acerola microparticles produced with WPI/hydrolysed collagen carriers (AWC) with higher solids recovery (53.5 ± 0.34% w/w), polyphenol retention (74.4 ± 0.44% w/w), high solubility in water (85.2 ± 0.4% w/w), total polyphenol content (128.45 ± 2.44 mg GAE/g) and good storage stability were selected to produce starch-based films by casting. As a result, cassava films with water vapour permeability of 0.29 ± 0.07 g mm/m2 h KPa, polyphenol content of 10.15 ± 0.22 mg GAE/g film and DPPH radical scavenging activity of 6.57 ± 0.13 μM TE/g film, with greater migration of polyphenol to water (6.30 ± 0.52 mg GAE/g film) were obtained. Our results show that the incorporation of phytochemical-rich fruit microparticles is a promising strategy to create biodegradable edible films.

Microencapsulation of organic coffee husk polyphenols: Effects on release, bioaccessibility, and antioxidant capacity of phenolics in a simulated gastrointestinal tract

Whey protein concentrate (WPC) and maltodextrin were used to microencapsulate polyphenols extract from organic coffee husks by spray drying. The microparticles were characterized and evaluated for their influence on the release, bioaccessibility, and antioxidant capacity of polyphenols in the simulated gastrointestinal tract. WPC as a single encapsulating agent promoted better yield (54.8%) of microparticles. The microparticles showed solubility above 92%, and lower hygroscopicity when encapsulated with maltodextrin alone (7.4%). Smaller diameter (6.78 µm), better encapsulation efficiency (89.1%) and retention of compounds (74.4%) were observed in microparticles with WPC in the composition. Polyphenols were completely released from the microparticles during simulated gastric digestion. The microparticles influenced the bioaccessibility of over 70% of the polyphenols in the intestinal phase. The microparticles showed rapid gastrointestinal release effect but favored the increase of bioaccessibility and preservation of the antioxidant capacity of polyphenols, especially those from the microparticles with WPC compared to the free extract.

Use of Micronization and Complex Coacervation to Preserve Antioxidant Properties of Flavonoids

The plant flavonoids taxifolin and rutin are among the best known and best studied antioxidants. In addition to their antioxidant properties, other pharmacobiological properties have been established for these substances. At the same time, taxifolin and rutin are chemically labile. They are prone to oxidative degradation and have poor water solubility. Under conditions of their real consumption, all this can lead to a significant reduction or complete loss of bioactivity of these flavonoids. Flavonoid modification and encapsulation techniques can be used to overcome these barrier factors. The use of micronization process for taxifolin and rutin allows changing the lipophilicity values of antioxidants. For micronized taxifolin, the log P value is 1.3 (1.12 for the control forms), and for rutin, it was 0.15 (-0.64 for the control forms). The antioxidant activity of micronized flavonoids has increased about 1.16 times compared to control forms. The present study evaluates the possibility of using encapsulation of premyconized flavonoids by complex coacervation, in order to preserve their antioxidant properties. The results of an in vitro digestion study show that the encapsulated forms of antioxidants retain their bioactivity and bioavailability better than their original forms. The bioavailability indices for the encapsulated forms of flavonoids are more than 1.6 times higher than for their original forms. The digested fractions of the encapsulated properties reveal better antioxidant properties than their original forms in in vitro tests evaluating the antioxidant properties on cultures of the protozoan Paramecium caudatum and human neuroblastoma SH-SY5Y cells. Encapsulated rutin indicates the highest activity, 0.64 relative to PMA. Thus, the studies represent the feasibility of using encapsulation to protect flavonoids during digestion and ensure the preservation of their antioxidant properties.

In vitro bioaccessibility evaluation of chlorophyll pigments in single and binary carriers

Chlorophyll was extracted and microencapsulated using different carrier agents. Subsequently, in vitro digestion was performed, and the bioaccessibility of chlorophyll in the different encapsulation systems was carried out. The zeta potential, particle size, and PDI were significantly modified after the micellarization of digested microcapsules. I-W-Chl presented with the highest total chlorophyll recovery and micellarization rate of 54% and 43%, respectively. In the aqueous micellar fraction, the different encapsulation systems had total chlorophylls, pheophytins, and pheophorbides ranging from 13 to 49%, 42 - 77%, and 3 - 22% respectively. The bioaccessibility of total chlorophyll pigment ranging from 7% to 20% is given in the following order: I-W-Chl > WPI-Chl > Z-Chl > Ca-Chl > SCChl^V > SCChl^C. The result established in this study shows that the carrier agent type could inhibit or mediate the bioaccessibility of chlorophyll with the potential to be an efficient delivery system for health promoting compounds.

Development of Spray Dried Spirulina Protein-Berry Pomace Polyphenol Particles to Attenuate Pollution-Induced Skin Damage: A Convergent Food-Beauty Approach

Spray drying (SD) microencapsulation of phytochemicals from berry pomaces with Spirulina protein (SP) was incorporated into a cosmeceutical topical formulation to mitigate pollution skin damage. Initially, microparticles produced with SP and polyphenols recovered from fruit pomaces (elderberry SP-EB and muscadine grape SP-MG) were characterized regarding physicochemical and phytochemical content (polyphenol load, carotenoid and phycocyanin contents and antioxidant activity). SP had low total phenolic content (7.43 ± 0.23 mg GAE/g DW), but complexation with elderberry or muscadine grape pomaces polyphenols led to a substantial increase (27.63 ± 1.15 SP-EB and 111.0 ± 2.6 mg GAE/g DW SP-MG). SP-MG particles had higher anthocyanin (26.87 ± 1.25 mg/g) and proanthocyanidin (9.02 ± 0.74 mg/g) contents compared to SP-EB particles. SP-MG were prioritized to prepare a topical gel to attenuate skin oxinflammatory markers and prevent skin barrier disruption using ex vivo human biopsies exposed to diesel engine exhaust (DEE). The immunofluorescence results showed increased oxidative protein damage and inflammation associated with impaired skin barrier function after DEE exposure while topical application of gel formulated with SP-MG mitigated these effects. Overall, this study demonstrated that protein-polyphenol complexation is a synergistic strategy to stabilize and deliver residual fruit/algae phytoactives into cosmeceutical products for skin health applications.

In vitro bioaccessibility evaluation of pheophytins in gelatin/polysaccharides carrier

The type of carrier agent could impact pheophytin stability and bioaccessibility. Hence, it is important to have an elaborate understanding on the extent and type of pheophytin transformation during in vitro digestion of microcapsules. Four kinds of protein/polysaccharides complex were used to fabricate pheophytin microcapsules and investigated for pigments bioaccessibility. With different carriers, pheophytin pigments showed new characteristics influencing particle size and zeta potential during in vitro digestion. Pheophytin b was widely transformed to pheophorbide b, confirming pheophorbidation of the b series in proper condition. No 15¹-hydroxy lactone chlorophyll or pheophytin derivatives were detected, indicating some protective effect of microencapsulation. Pheophytins loaded in gelatin-pectin complex exhibited a relatively higher recovery rate, micellarization rate, and bioaccessibility index. The result presented in this study shows that the type of carrier agent could initiate the removal of phytyl groups in pheophytins and also inhibit or mediate their bioaccessibility.

Dual improvement in curcumin encapsulation efficiency and lyophilized complex dispersibility through ultrasound regulation of curcumin-protein assembly

Ultrasound has a recognized ability to modulate the structure and function of proteins. Discovering the influential mechanism of ultrasound on the intramolecular interactions of egg-white protein isolate-curcumin (EPI-Cur) nanoparticles and their intermolecular interaction during freeze drying and redispersion is meaningful. In this study, under the extension of pre-sonication time, the protein solubility, surface hydrophobicity, and curcumin encapsulation rate showed an increasing trend, reaching the highest value at 12 min of treatment. However, the values decreased under the followed extension of ultrasound time. After freeze drying and redispersion were applied, the EPI-Cur sample under 12 min of ultrasound treatment exhibited minimal aggregation degree and loss of curcumin. The retention and loading rates of curcumin in the lyophilized powder reached 96 % and 33.60 mg/g EPI, respectively. However, under excessive ultrasound of >12 min, scanning electron microscopy showed distinct blocky aggregates. Overexposure of the hydrophobic region of the protein triggered protein-mediated hydrophobic aggregation after freeze drying. X-ray diffraction patterns showed the highest crystallinity, indicating that the free curcumin-mediated hydrophobic aggregation during freeze drying was enhanced by the concentration effect and intensified the formation of larger aggregates. This work has practical significance for developing the delivery of hydrophobic active substances. It provides theoretical value for the dynamic dispersity change in protein-hydrophobic active substances during freeze drying and redissolving.