Polysaccharides as Carriers of Polyphenols: Comparison of Freeze-Drying and Spray-Drying as Encapsulation Techniques

Microencapsulation of highly concentrated polyphenolic compounds from purple corn pericarp by spray-drying with various biomacromolecules

Colored corn pericarp contains unusually high amounts of industrially valuable phytochemicals, such as anthocyanins, flavanols, flavonoids, and phenolic acids. Polyphenols were extracted in an aqueous solution and spray-dried to produce microencapsulates using four carrier materials, namely, maltodextrin (MD), gum arabic (GA), methylcellulose (MC), and skim milk powder (SMP) at three concentrations (1, 2, and 3 %, respectively). The encapsulates were evaluated for their polyphenolic contents using spectrophotometric techniques and HPLC analyses, and their antioxidant properties were evaluated using four different assays. The physicochemical properties of encapsulates were analyzed by measuring the zeta potential (ZP), particle size distribution, water solubility index (WSI), water absorption index (WAI), and color parameters. Structural and thermal properties were evaluated using Fourier transform infrared spectroscopy (FTIR), optical profilometry, and differential scanning calorimetry (DSC) analyses. Comparative analysis of structural characteristics, particle size distribution, zeta potential, WSI, WAI, and aw of the samples confirmed the successful formulation of encapsulates. The microencapsulates embedded with 1 % concentrations of MD, MC, GA, or SMP retained polyphenolic compounds and exhibited noteworthy antioxidant properties. The samples encapsulated with GA or MD (1 %) demonstrated superior physicochemical, color, and thermal properties. Comprehensive metabolomic analysis confirmed the presence of 38 phytochemicals in extracts validating the spray-drying process.

Lyophilized Emulsions of Thymol and Eugenol Essential Oils Encapsulated in Cellulose

Efforts to tap into the broad antimicrobial, insecticidal, and antioxidant activities of essential oils (EOs) are limited due to their strong odor and susceptibility to light and oxidation. Encapsulation of EOs and subsequent drying overcome these limitations and extend their applications. This study characterized freeze-dried (lyophilized) emulsions of eugenol (EU) and thymol (TY) EOs, encapsulated by chemically unmodified cellulose, a sustainable and low-cost resource. High-resolution scanning electron microscopy showed successful lyophilization. While the observed "flake-like" structure of the powders differed significantly from that of the emulsified microcapsules, useful properties were retained. Fourier transform infrared spectroscopy confirmed the presence of EOs in their corresponding powders and thermo-gravimetric analysis demonstrated high encapsulation efficiency (87-88%), improved thermal stability and resistance to evaporation, and slow EO release rates in comparison to their free forms. The lightweight and low-cost cellulose encapsulation, together with the results showing retained properties of the dried powder, enable the use of EOs in applications requiring high temperatures, such as EO incorporation into polymer films, that can be used to protect agricultural crops from microbial infections.

Developmental Formulation Principles of Food Preservatives by Nanoencapsulation-Fundamentals, Application, and Challenges

The role of food additives is to preserve food by extending shelf life and limiting harmful microorganism proliferation. They prevent spoilage by enhancing the taste and safety of food by utilizing beneficial microorganisms and their antimicrobial metabolites. Current advances in food preservation and processing utilize green technology principles for green preservative formulation, enhancing nutrition and supplying essential micronutrients safely, while also improving quality, packaging, and food safety. Encapsulation is gaining attention for its potential to protect delicate materials from oxidative degradation and extend their shelf life, thereby ensuring optimal nutrient uptake. Nanoencapsulation of bioactive compounds has significantly improved the food, pharmaceutical, agriculture, and nutraceutical industries by protecting antioxidants, vitamins, minerals, and essential fatty acids by controlling release and ensuring delivery to specific sites in the human body. This emerging area is crucial for future industrial production, improving the sensory properties of foods like color, taste, and texture. Research on encapsulated bioactive compounds like bacteriocins, LAB, natamycin, polylysine, and bacteriophage is crucial for their potential antioxidant and antimicrobial activities in food applications and the food industry. This paper reviews nanomaterials used as food antimicrobial carriers, including nanoemulsions, nanoliposomes, nanoparticles, and nanofibers, to protect natural food antimicrobials from degradation and improve antimicrobial activity. This review discusses nanoencapsulation techniques for biopreservative agents like nisin, poly lysine, and natamycin, focusing on biologically-derived polymeric nanofibers, nanocarriers, nanoliposomes, and polymer-stabilized metallic nanoparticles. Nanomaterials, in general, improve the dispersibility, stability, and availability of bioactive substances, and this study discusses the controlled release of nanoencapsulated biopreservative agents.

pH-dependent stability of major betalains in the encapsulated beetroot extracts (Beta vulgaris L.)

Betalain is a water-soluble pigment contained in Caryophyllales plants. It not only holds potential as a natural food colorant but also offers various health benefits, acting as an antioxidant. This study focused on analyzing the pH-dependent stability of encapsulated betalain pigments extracted from red beetroot (Beta vulgaris L.) using methods such as absorption spectroscopy, HPLC, and LC-MS. The major pigments identified were vulgaxanthin I, betanin, isobetanin, and neobetanin, alongside minor components, including three betaxanthin species and a degradation product known as betalamic acid. Spectrophotometric analyses revealed that above pH 8, the betalain peak at 435 nm decreased and red-shifted to a peak at 549 nm, a shift that could be reversed through neutral pH treatment. At pH 11, a new broad peak appeared at 410 nm and was identified as betalamic acid. To assess the pH-dependency of each betalain, the targeted betalains were separated and quantified through HPLC after incubation across a wide pH range of 2-11 and during storage. After 3 days of storage in highly alkaline conditions (pH 10-11), major betalains, with the exception of neobetanin, underwent significant degradation. Conversely, these pigments displayed relative stability in acidic conditions. In contrast, neobetanin showed vulnerability to acidic conditions but exhibited tolerance to alkaline pH levels of 10-11. The degradation product, betalamic acid, demonstrated a similar susceptibility to alkaline pH as betanins. In conclusion, the significant stability decrease under highly alkaline conditions results not only from the hydrolytic reaction of betalains but also from the degradation of betalamic acid itself. PRACTICAL APPLICATION: Encapsulation methods are used to enhance the stability of betalains against temperature variations; however, the effects of pH, especially when considering individual betalain species, are not well understood. Despite betalains exhibiting similar features and being suitable for a wide pH range from acid to alkaline conditions, they are significantly affected by alkaline pH levels exceeding 10, as well as by storage duration. This study demonstrated the application of encapsulation to pH-dependent stability, and the findings offer valuable insights and a fresh perspective on betalains as red biocolorants, extending their potential application to a wide range of pH-controlled food products.

Recent progress in promoting the bioavailability of polyphenols in plant-based foods

Polyphenols are important constituents of plant-based foods, exhibiting a range of beneficial effects. However, many phenolic compounds have low bioavailability because of their low water solubility, chemical instability, food matrix effects, and interactions with other nutrients. This article reviews various methods of improving the bioavailability of polyphenols in plant-based foods, including fermentation, natural deep eutectic solvents, encapsulation technologies, co-crystallization and amorphous solid dispersion systems, and exosome complexes. Several innovative technologies have recently been deployed to improve the bioavailability of phenolic compounds. These technologies may be utilized to increase the healthiness of plant-based foods. Further research is required to better understand the mechanisms of action of these novel approaches and their potential to be used in food production.

Impact of polyphenol-loaded edible starch nanomaterials on antioxidant capacity and gut microbiota

Starch nanoparticles (SNPs) have the capability to adsorb polyphenol components from apple pomace efficiently, forming bound polyphenols (P-SNPs). These bound polyphenols may have potential bioactivities to affect human health positively. Therefore, in-depth in vivo observation of the antioxidant activity and evaluation of its gut microbiota regulatory function are essential. The results revealed that P-SNPs indicated significant scavenging abilities against DPPH, ABTS, and hydroxyl radicals. Furthermore, the nanomaterials exhibited non-toxic properties, devoid of hepatorenal and intestinal damage, while concurrently stimulating the production of short-chain fatty acids (SCFAs) within the gastrointestinal tract. Notably, P-SNPs significantly enhanced antioxidant capacity in serum, liver, and kidney tissues, fostering the proliferation of beneficial bacteria (Lactobacillus, Bacillus, norank_f__Muribaculaceae) while suppressing pathogenic bacterial growth (Helicobacter, Odoribacter). This study proposes a novel research concept for the scientific use of polyphenols in promoting gut health.

Improving the storage and oxidative stability of essential fatty acids by different encapsulation methods; a review

Linoleic acid and α-linolenic acid are the only essential fatty acids (EFAs) known to the human body. Other fatty acids (FAs) of the omega-6 and omega-3 families originate from linoleic acid and α-linolenic acid, respectively, by the biological processes of elongation and desaturation. In diets with low fish consumption or vegetarianism, these FAs play an exclusive role in providing two crucial FAs for maintaining our body's vital functions; docosahexaenoic acid and arachidonic acid. However, these polyunsaturated FAs are inherently sensitive to oxidation, thereby adversely affecting the storage stability of oils containing them. In this study, we reviewed encapsulation as one of the promising solutions to increase the stability of EFAs. Accordingly, five main encapsulation techniques could be classified: (i) spray drying, (ii) freeze drying, (iii) emulsification, (iv) liposomal entrapment, and (v) other methods, including electrospinning/spraying, complex coacervation, etc. Among these, spray drying was the frequently applied technique for encapsulation of EFAs, followed by freeze dryers. In addition, maltodextrin and gum Arabic were the main wall materials in carriers. Paying attention to industrial scalability and lower cost of the encapsulation process by the other methods are the important aspects that should be given more attention in the future.

Spray-freeze-drying as emerging and substantial quality enhancement technique in food industry

Spray freeze drying is an emerging technology in the food industry with numerous applications. Its ability to preserve food quality, maintain nutritional value, and reduce bulk make it an attractive option to food manufacturers. Spray freeze drying can be used to reduce the water content of foods while preserving the shelf life and nutritional value. Spray freeze-drying of food products is a process that involves atomizing food into small droplets and then flash-freezing them. The frozen droplets are then placed in a vacuum chamber and heated, causing the liquid to evaporate and the solid particles to become a dry powder. Spray freeze drying has become a valuable tool for the food industry through its ability to process a wide range of food products. This review's prime focus is understanding spray freeze-dried approaches and emphasizing their applicability in various products.

Antioxidant Potential of Spray- and Freeze-Dried Extract from Oregano Processing Wastes, Using an Optimized Ultrasound-Assisted Method

Origanum vulgare is recognized worldwide for its numerous applications, in the food industry and beyond. However, the extraction of its essential oils generates a significant amount of waste. The aim of this research was to achieve the valorization of solid waste from oregano hydro-distillation, by (i) optimizing the ultrasound extraction of antioxidants, (ii) evaluating the effect of spray and freeze drying on the extract's physicochemical properties, and (iii) characterizing the obtained powder by its antioxidant capacity. A central composite design of experiments was used to optimize the sample/solvent ratio, ethanol/water ratio, and extraction time. The extract was analyzed for its antioxidant potential by determining the percentage of DPPH inhibition, FRAP, and total phenolic content (TPC). The GAB model best fit the data for the moisture sorption isotherm of the resulting powder. The antioxidant activity of the powders was tested in a ground-beef food system. The TPC was maximized at times longer than 58 min, a sample/solvent ratio between 0.058 and 0.078, and a ratio of ethanol/water around 1. Neither drying method significantly affected the antioxidant properties of the extract, even though the resulting powders from each showed a different morphology (determined using SEM). Encapsulation with maltodextrin protected the spray-dried extract during a 6-month storage period. Powders from both drying methods equally retarded lipid oxidation, and were comparable to the synthetic antioxidant BHT. It is concluded that oregano processing waste is a potent source of antioxidants, and that its dried extract, via an ultrasound-assisted process, can potentially be used as a natural alternative to synthetic antioxidants.

Encapsulation of Hydrophobic Apigenin into Small Unilamellar Liposomes Coated with Chitosan Through Ethanol Injection and Spray Drying

Despite the multiple health benefits, natural flavonoid apigenin has poor aqueous solubility that restricts its delivery in foods. This study investigated the potential of spray-dried chitosan-coated liposomes prepared from scalable methods for the food industry as the delivery carriers for apigenin. Apigenin-loaded small unilamellar liposomes produced from ethanol injection had an encapsulation efficiency of 74.88 ± 5.31%. They were electrostatically stabilised via chitosan coating (0.25% w/v) and spray-dried. Spray-dried chitosan-coated apigenin liposomes (SCAL) exhibited the following powder characteristics: yield 66.62 ± 3.08%, moisture content 4.33 ± 0.56%, water activity 0.2242 ± 0.0548, particle size 10.97 ± 1.55 μm, nearly spherical morphology with wrinkles and dents under microscopic observation. Compared with the unencapsulated apigenin, SCAL demonstrated improved aqueous solubility (10.22 ± 0.18 mg/L), higher antioxidant capacity, and stability against simulated gastrointestinal digestion. The chitosan coating gave a slower in-vitro release of apigenin in SCAL (77.0 ± 6.2%) than that of uncoated apigenin liposomes (94.0 ± 5.3%) at 12 h. The apigenin release kinetics from SCAL could be represented by the Korsmeyer-Peppas model (R2 = 0.971). These findings suggest that SCAL could be a promising delivery system of apigenin for functional food applications.

Exploring the Potential of Wild Andean Blueberries for Powdered Juice Production through Spray Drying

The Andean blueberry (Vaccinium meridionale Sw) is an underutilized wild fruit native to South America. It is known for its antioxidant properties and potential health benefits. In this study, Andean blueberry juice powders were produced via spray drying, using maltodextrin (MD), gum Arabic (GA) or a combination of both (MD:GA) as wall materials. The spray-dried juices were analyzed for the recovery percentage of total polyphenols and monomeric anthocyanins, as well as for their physicochemical and technological properties. Results showed that the type of carrier agent used caused statistically significant differences in the bioactive content and the antioxidant activity of the powders (p < 0.05). It was found that the MD samples has the highest monomeric anthocyanins content (0.88 ± 0.02 mg cyanidin 3-glucoside equivalents/g) and the highest anthocyanins recovery (96.3 ± 1.7%), while the MD:GA powders showed the highest values of total polyphenol content (5.70 ± 0.09 mg gallic acid equivalents/g), DPPH scavenging capacity (2.49 ± 0.02 mg gallic acid equivalents/g) and phenolics recovery (87.2 ± 1.1%). Furthermore, all the spray-dried powders exhibited low moisture content (<5.5%) and water activity (<0.40), as well as high solubility in water (>94%) and good flowability. Future prospects include evaluating the stability of the Andean blueberry juice powders during storage and exploring the formulation of new foods and beverages that incorporate these spray-dried powders.

Physicochemical Properties, Antioxidant Capacity, and Bioavailability of Laurus nobilis L. Leaf Polyphenolic Extracts Microencapsulated by Spray Drying

Laurel (Laurus nobilis L.) leaves are a rich source of polyphenols with the potential for use in functional foods, where the main obstacle is their low stability and bioavailability, which can be improved by spray drying (SD). This research examined the influence of SD parameters, including inlet temperature (120, 150, and 180 °C), carrier type (β-cyclodextrin (β-CD); β-CD + maltodextrin (MD) 50:50; β-CD + gum arabic (GA) 50:50), and sample:carrier ratio (1:1, 1:2 and 1:3) on the physicochemical properties, encapsulation efficiency, polyphenolic profile, antioxidant capacity and bioaccessibility of laurel leaf polyphenols. The highest encapsulation efficiency was achieved at a sample:carrier ratio 1:2 and the temperature of 180 °C by using either of the applied carriers. However, the application of β-CD + MD 50:50 ensured optimal solubility (55.10%), hygroscopicity (15.32%), and antioxidant capacity (ORAC 157.92 μmol Trolox equivalents per g of powder), while optimal moisture content (3.22%) was determined only by temperature, demanding conditions above 150 °C. A total of 29 polyphenols (dominantly flavonols) were identified in the obtained powders. SD encapsulation increased the bioaccessibility of laurel flavonols in comparison to the non-encapsulated extract by ~50% in the gastric and ~10% in the intestinal phase, especially for those powders produced with carrier mixtures.

Nutmeg Essential Oil, Red Clover, and Liquorice Extracts Microencapsulation Method Selection for the Release of Active Compounds from Gel Tablets of Different Bases

The current study presents the most suitable method for encapsulating nutmeg essential oil with liquorice and red clover. Two widely used methods, spray-drying and freeze-drying, were employed to find the most suitable for essential oil volatile compounds’ protection. Results showed that freeze-dried capsules (LM) had a higher yield (85.34%) compared to the exact formulation of spray-dried microcapsules (SDM)—45.12%. All the antioxidant and total phenolic compounds’ results obtained with the LM sample were significantly higher compared with SDM. LM microcapsules were incorporated in two different bases with no additional sugar (gelatin and pectin) for targeted release. Pectin tablets had firmer and harder texture properties, while gelatin tablets had a more elastic texture. There was a significant impact on texture changes caused by microcapsules. Microencapsulated essential oil with extracts can be used alone or in a gel base (pectin or gelatin, depending on user preferences). It could be an effective product to protect the active volatile compounds and regulate the release of active compounds and give a pleasant taste.

Beneficial Effects of Red Wine Polyphenols on Human Health: Comprehensive Review

Polyphenols are secondary plant metabolites synthesized during the development of the grape berry as a response to stress conditions. They are important constituents in red wines that contribute to the sensory properties and antioxidant activity of wines. Due to the development of highly sophisticated analytical devices, it is now possible to characterize the structure of highly polymerized polyphenols and obtain a full polyphenol profile of red wines. Red wine polyphenols include the ones present in grapes as well as new polyphenol products formed during the winemaking process. Among them, the most important groups and their representatives are flavanols (catechin), stilbenes (trans-resveratrol), flavonols (quercetin) and hydroxybenzoic acids (gallic acid). It is known that polyphenols exhibit beneficial effects on human health, such as anti-inflammatory, anticarcinogenic and cardio-protective effects. Many studies have been conducted on the health effects of red wine polyphenols in cancer chemopreventive activities, neuroprotective effects and impact on cardiovascular diseases, gut microbiota in humans, etc. This review will provide major scientific findings on the impact of red wine polyphenols on human health as well as a review of polyphenols present in red wines and their main features.

Flavour encapsulation: A comparative analysis of relevant techniques, physiochemical characterisation, stability, and food applications

Flavour is an important component that impacts the quality and acceptability of new functional foods. However, most flavour substances are low molecular mass volatile compounds, and direct handling and control during processing and storage are made difficult due to susceptibility to evaporation, and poor stability in the presence of air, light, moisture and heat. Encapsulation in the form of micro and nano technology has been used to address this challenge, thereby promoting easier handling during processing and storage. Improved stability is achieved by trapping the active or core flavour substances in matrices that are referred to as wall or carrier materials. The latter serve as physical barriers that protect the flavour substances, and the interactions between carrier materials and flavour substances has been the focus of many studies. Moreover, recent evidence also suggests that enhanced bioavailability of flavour substances and their targeted delivery can be achieved by nanoencapsulation compared to microencapsulation due to smaller particle or droplet sizes. The objective of this paper is to review several relevant aspects of physical-mechanical and physicochemical techniques employed to stabilize flavour substances by encapsulation. A comparative analysis of the physiochemical characterization of encapsulates (particle size, surface morphology and rheology) and the main factors that impact the stability of encapsulated flavour substances will also be presented. Food applications as well as opportunities for future research are also highlighted.

Encapsulating Calendula arvensis (Vaill.) L. Florets: UHPLC-HRMS Insights into Bioactive Compounds Preservation and Oral Bioaccessibility

Wild edible plants, once consumed in times of famine or for health purposes, today represent an interesting dietary supplement, aimed at enriching local dishes and/or formulating healthy nutraceutical products. In fact, the broad content of different, and diversely bioactive, specialized metabolites therein suggests new scenarios of use which, in order to be as functional as possible, must maximize the bioactivity of these compounds while preserving their chemistry. In this context, based on a recent investigation on the metabolic profile of the organs of Calendula arvensis that highlighted that florets are abundant in flavonol glycosides and triterpene saponins, the freeze-drying encapsulation of their alcoholic extract (FE) into maltodextrin (MD) was investigated. FE-MD chemical composition was evaluated using Fourier Transform InfraRed spectroscopy (FTIR), while ultra-high performance liquid chromatography coupled with high-resolution tandem mass spectrometry (UHPLC-HRMS/MS) techniques were employed to unravel FE compound preservation also during in vitro simulated digestion. The establishment of H-bonds between FE compounds and MD hydroxyl groups was in line with FE-MD biocompatibility in Caco-2 cells, while in vitro digestion mostly affected structural integrity and/or diversity. Flavonol compounds underwent deglycosylation and demethylation, while deacylation, beyond oxidation, involved triterpene saponins, which massively preserve their aglycone core.

Effect of Spray Drying Encapsulation on Nettle Leaf Extract Powder Properties, Polyphenols and Their Bioavailability

Nettle (Urtica dioica L.) is a plant rich in a health-promoting compounds such as polyphenols, which are sensitive and unstable compounds with low bioavailability, that need to be stabilized and protected from external influences. Therefore, the aim of this study was to examine how the temperature, type of carrier and sample to carrier ratio influence the physicochemical properties and encapsulation and loading capacity of the nettle leaf extract powder and examine the effect of encapsulation on the antioxidant capacity and bioavailability of polyphenols. The process yield ranged from 64.63–87.23%, moisture content from 1.4–7.29%, solubility from 94.76–98.53% and hygroscopicity from 13.35–32.92 g 100 g⁻¹. The highest encapsulation (98.67%) and loading (20.28%) capacities were achieved at 160 °C, β-CD:GA (3:1) and sample:carrier ratio of 1:3. Extracts encapsulated at selected conditions showed high antioxidant capacity and distinct polyphenolic profile comprised of 40 different compounds among which cinnamic acids were the most abundant. Moreover, the encapsulation increased the bioavailability of nettle leaf polyphenols, with the highest amount released in the intestinal phase. Thus, the obtained encapsulated extract represents a valuable source of polyphenols and may therefore be an excellent material for application in value-added and health-promoting products.