Developing microencapsulated powders containing polyphenols and pectin extracted from Georgia-grown pomegranate peels

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.

Pectins Rich in RG-I Extracted from Watermelon Peel: Physicochemical, Structural, Emulsifying, and Antioxidant Properties

RG-I pectin has excellent health benefits, but its raw materials are relatively scarce, and its complex structure often breaks down its side-chain structure during the extraction process. In this study, the physicochemical and antioxidant properties of a branched-chain-rich pectin gained from watermelon peel were demonstrated, and the structure-function relationships of RG-I-enriched pectin and emulsification properties were investigated. Fourier transform infrared spectroscopy, high-performance anion exchange chromatography, high-performance gel permeation chromatography, nuclear magnetic resonance spectroscopy, and methylation analyses reveal it as acetylated, low-methoxylated pectin, rich in RG-I side chains (MW: 1991 kDa, RG-I = 66.17%, methylation degree: 41.45%, (Ara + Gal)/Rha: 20.59%). RPWP outperforms commercial citrus pectin in emulsification and stability, significantly preventing lipid oxidation in emulsions. It also exhibits free radical scavenging abilities, contributing to its effectiveness in preventing lipid oxidation. Emulsions made with RPWP show higher viscosity and form a weak gel network (G' > G″), enhancing stability by preventing phase separation. These findings position watermelon peel as a good source of RG-I pectin and deepen our understanding of RPWP behavior in emulsion systems, which may be useful in the food and pharmaceutical fields.

Effects of the spray-drying process using maltodextrin on bioactive compounds and antioxidant activity of the pulp of the tropical fruit açai (Euterpe oleracea Mart.)

Aҫai fruit is characterized by the properties of its bioactive compounds; however, this fruit is highly perishable and its compounds are sensitive when exposed to non-optimal environmental factors. Therefore, the objective of this study was to encapsulate the fruit pulp by spray drying to improve the nutritional value and extend the shelf life of the products derived from acai fruit. Maltodextrin was used as a wall material and the process was optimized to obtain the desirable values of the response variables. For this, a central compound design (CCD) was developed to determine the influence of temperature (110-170 °C) and the wall material proportion (5-15 %) on dependent variables: the retention of ascorbic acid, moisture percentage, hygroscopicity, solubility, water activity, and yield. Furthermore, the effects of spray drying on bioactive compounds (AA, TPC, TFC, TA, TCC, GA, CT, and QC) and antioxidant activity (ABTS, DPPH, and ORAC) were evaluated. The maximum design temperature (170 °C) and wall material proportion (15 %) significantly influenced the response variables where encapsulation was applied, with high ascorbic acid retention (96.886 %), low moisture (0.303 %), low hygroscopicity (7.279 g/100 g), low level of water activity (0.255), a water solubility index of 23.206 %, and a high yield of 70.285 %. The bioactive compounds analyzed and the antioxidant capacity presented significant retention values for AA (96.86 %), TPC (65.13 %), TFC (82.09 %), TA (62.46 %), TCC (7.28 %), GA (35.02 %), CT (49.03 %), QC (37.57 %), ABTS (81.24 %), DPPH (75.11 %), and ORAC (15.68 %). Therefore, it is concluded that the powder obtained under these conditions has desirable physical properties, and the drying process preserved a notable retention of bioactive compounds and their antioxidant activities.

Development of microencapsulated grape juice powders using black 'Isabel' grape peel pectin and application in jelly formulation with enhanced in vitro bioaccessibility of anthocyanins

In this study, pigmented pectin (grape pectin, GP) was extracted from the peels of black Isabel grapes. This highly methoxylated GP was composed mainly of galacturonic acid, arabinose, and other neutral monosaccharides. Its red color was ascribed to the anthocyanin content, and the main contribution was from malvidin-3-O-glucoside. To improve the yield and color properties of spray-dried Isabel grape juice powders, maltodextrin (MD) was substituted with this colored GP. When 25% of MD was substituted with GP, the powder yield increased from 46.0% to 60.4%, but it decreased to 21% when the substitution was 40%. GP inclusion increased the encapsulation efficiency of total anthocyanin in powders from 55.70% to 88.66%. When this spray-dried grape juice powder containing GP was utilized in a jelly recipe (4%-10%), a higher level of inclusion yielded stronger and more brittle jellies. When the jellies containing varying amounts of GP were subjected to in vitro digestion, the formulation with a higher amount of GP yielded a higher recovery of anthocyanins. In addition to being utilized as a carrier agent for spray-drying applications, this pigmented GP can also be tailored for a variety of applications, such as the development of pH-sensitive edible films and functional beverage formulations.

Multifunctional Pomegranate Peel Microparticles with Health-Promoting Effects for the Sustainable Development of Novel Nutraceuticals and Pharmaceuticals

Recovering the bioactive components from pomegranate peel (PP) in the fruit-processing industry has attracted great attention in terms of minimizing the waste burden, as well as providing a new source of a multitude of functional compounds. The present study aimed to develop a feasible microencapsulation process of PP extract by using pectin and a pectin/2-hydroxypropyl-β-cyclodextrin (HP-β-CD) blend as coating materials. Microsized powders obtained by a spray drying technique were examined in terms of technological characteristics, exhibiting high powder yield and desirable moisture content, flowability, and cohesive properties. Assuming that the interactions with the used biopolymers occur on the surface hydrophobic domain, their presence significantly improved the thermal stability of the microencapsulated powders up to 200 °C. The health-promoting effects of PP have been associated with its high content in ellagitannins, particularly punicalagin. The obtained PP powders exhibited strong antioxidant and hypoglycemic potential, while an antimicrobial assay revealed their potent activity against Gram-positive bacteria. Additionally, an in vitro release study suggested that the used biopolymers can modify the release of target bioactive compounds, thus establishing a basis for developing an oral-controlled release system. Altogether, biowaste valorization from PP by the production of effective multifunctional microsized powders represents a sustainable way to obtain novel nutraceuticals and/or pharmaceuticals.

Development of Pectin Particles as a Colon-Targeted Marjoram Phenolic Compound Delivery System

Marjoram is a culinary herb that has been widely employed in folk medicine and presents a high content in phenolics. Thus, the aim of this project was to design formulations to encapsulate phenolic compounds from marjoram to allow their release in the colon. For this purpose, pectin was used as an encapsulating agent, applying two different encapsulation techniques (ionic gelation and spray-drying), followed by a CaCl2 bath. The ionic gelation technique showed a higher yield (77%) compared to spray-drying (31%), and the particles obtained were smaller (267 nm). However, the microparticles obtained by spray-drying presented a higher encapsulation efficiency (93%). Moreover, spray-dried microparticles protected a higher percentage of the encapsulated phenolics from the action of gastrointestinal pHs and enzymes. Hence, the results showed that spray-drying was a more appropriate technique than ionic gelation for the encapsulation of marjoram phenolics in order to protect them during the gastrointestinal step, facilitating their arrival in the colon. These microparticles would also be suitable for inclusion in food matrices for the development of phenolic colon delivery systems.

Microencapsulated polyphenol extracts from Georgia-grown pomegranate peels delay lipid oxidation in salad dressing during accelerated and ambient storage conditions

Lipid oxidation is a major cause of quality deterioration in salad dressings. This study evaluated the effect of incorporating microencapsulated polyphenol extracts via spray drying from pomegranate peels (MPP) to delay lipid oxidation in Italian-style salad dressings (ISD) during accelerated (55°C) and ambient (25°C) storage conditions. ISDs, prepared at high (5000 rpm) and low (250 rpm) shear rates conditions, were formulated with unencapsulated polyphenol extracts from pomegranate peels (PPP), MPP, and/or grape seed extract (GSE). Lipid oxidation in ISDs was evaluated by measuring peroxide value (PV), iodine value (IV), and TBARS, stored in accelerated and ambient conditions for 21 days and 8 weeks, respectively. Tannis in extracts were measured via HPLC-DAD and the total hydrolyzable tannin content of PPP and MPP was 283.09 and 427.74 (mg/g extract), respectively. Condensed tannins were not detected in PPP and MPP but were found in GSE (348.53 mg/g extract). Salad dressings prepared at high shear rates had significantly (p < .05) higher emulsion stability than those homogenized at low shear rates. Mixing conditions did not affect the lipid oxidative stability of IDSs. Salad dressing stored under accelerated storage had higher lipid oxidation (higher PV, lower IV, and higher TBARS) after 21 days than IDSs stored under ambient conditions for 8 weeks. ISDs prepared with MPPP showed significantly (p < .05) lower lipid oxidation than the other ISDs at the end of the shelf life studies. Results from the accelerated storage suggested that incorporating MPP could have extended the shelf life of IDSs by 20% compared to using unencapsulated polyphenol extracts. The study demonstrated that MPP delays lipid oxidation in ISDs during storage more effectively than unencapsulated extracts. MPP may serve as a natural and effective functional food ingredient for controlling lipid oxidation in high-lipid and acidified foods.

Comparative Analysis of Concurrent (CC), Mixed Flow (MX), and Combined Spray Drying Configurations on the Physicochemical Characteristics of Satsuma Mandarin (Citrus unshiu) Juice Powders

Satsuma mandarins are good sources of vitamin C and can be used as raw materials to produce novel plant-based food ingredients including satsuma mandarin juice powders (SJP). Food powders produced via spray drying often show thermal degradation due to the drying conditions and high drying air temperatures. The aim of this study was to evaluate the effect of using different spray drying configurations, including concurrent (CC), mixed flow (MX), and combined (CC + MX), at two inlet air temperatures (160 and 180 °C) on the physicochemical properties of SJP. Remarkably, SJP produced using the CC spray drying configuration exhibited a higher vitamin C content (3.56-4.01 mg/g) and lower moisture levels (15.18-16.35 g/100 g) than powders produced via MX or CC + MX. The vitamin C content of MX and CC + MX powders ranged from 2.88 to 3.33 mg/g. Meanwhile, all SJP had water activity values below 0.19. Furthermore, MX powders displayed the largest mean particle sizes (D50) (8.69-8.83 µm), higher agglomeration, and a rapid dissolution. Despite these differences, all SJP variants exhibited consistent color, surface area, and pore volumes. Notably, powders dried at higher inlet air temperatures (180 °C) showed less vitamin C content and increased thermal damage when compared with powders dried at 160 °C inlet air temperature. This study demonstrated the feasibility of producing high-quality SJP with an extended shelf life. SJP can be used as a novel plant-based ingredient in different food applications.

Current progress in valorization of food processing waste and by-products for pectin extraction

Food processing waste and by-products such as peel of citrus fruit, melon, mango, pineapple, etc. and fruit pomace can be utilized for manufacturing of several high-value products. Valorization of these waste and by-products for extraction of pectin, can help offset growing environmental concerns, facilitate value-addition of by-products and their sustainable uses. Pectin has many applications in food industries such as gelling, thickening, stabilizing, and emulsifying agent, and as a dietary fibre. This review elaborates on various conventional and advanced, sustainable pectin extraction techniques, and paints a comparative picture between them considering extraction efficiency, quality, and functionality of the pectin. Conventional acid, alkali, and chelating agents-assisted extraction have been profusely used for pectin extraction, but advanced extraction technologies e.g., enzyme, microwave, supercritical water, ultrasonication, pulse electric field and high-pressure extraction are preferred due to less energy consumption, better quality product, higher yield, and minimal or no generation of harmful effluent.

Nanostructured steady-state nanocarriers for nutrients preservation and delivery

Food bioactives possess specific physiological benefits of preventing certain diet-related chronic diseases or maintain human health. However, the limitations of the bioactives are their poor stability, lower water solubility and unacceptable bioaccessibility. Structure damage or degradation is often found for the bioactives under certain environmental conditions like high temperature, strong light, extreme pH or high oxygen concentration during food processing, packaging, storage and absorption. Nanostructured steady-state nanocarriers have shown great potential in overcoming the drawbacks for food bioactives. Various delivery systems including solid form delivery system, liquid form delivery system and encapsulation technology have been developed. The embedded food nutrients can largely decrease the loss and degradation during food processing, packaging and storage. The design and application of stimulus and targeted delivery systems can improve the stability, bioavailability and efficacy of the food bioactives upon oral consumption due to enzymatic degradation in the gastrointestinal tract. The food nutrients encapsulated in the smart delivery system can be well protected against degradation during oral administration, thus improving the bioavailability and releazing controlled or targeted release for food nutrients. The encapsulated food bioactives show great potential in nutrition therapy for sub-health status and disease. Much effort is required to design and prepare more biocompatible nanostructured steady-state nanocarriers using food-grade protein or polysaccharides as wall materials, which can be used in food industry and maintain the human health.

Recent Developments in the Microencapsulation of Fish Oil and Natural Extracts: Procedure, Quality Evaluation and Food Enrichment

Due to the beneficial health effects of omega-3 fatty acids and antioxidants and their limited stability in response to environmental and processing factors, there is an increasing interest in microencapsulating them to improve their stability. However, despite recent developments in the field, no specific review focusing on these topics has been published in the last few years. This work aimed to review the most recent developments in the microencapsulation of fish oil and natural antioxidant compounds. The impact of the wall material and the procedures on the quality of the microencapsulates were preferably evaluated, while their addition to foods has only been studied in a few works. The homogenization technique, the wall-material ratio and the microencapsulation technique were also extensively studied. Microcapsules were mainly analyzed for size, microencapsulation efficiency, morphology and moisture, while in vitro digestion, flowing properties, yield percentage and Fourier transform infrared spectroscopy (FTIR) were used more sparingly. Findings highlighted the importance of optimizing the most influential variables of the microencapsulation procedure. Further studies should focus on extending the range of analytical techniques upon which the optimization of microcapsules is based and on addressing the consequences of the addition of microcapsules to food products.

From Pomegranate Byproducts Waste to Worth: A Review of Extraction Techniques and Potential Applications for Their Revalorization

The food industry is quite interested in the use of (techno)-functional bioactive compounds from byproducts to develop ‘clean label’ foods in a circular economy. The aim of this review is to evaluate the state of the knowledge and scientific evidence on the use of green extraction technologies (ultrasound-, microwave-, and enzymatic-assisted) of bioactive compounds from pomegranate peel byproducts, and their potential application via the supplementation/fortification of vegetal matrixes to improve their quality, functional properties, and safety. Most studies are mainly focused on ultrasound extraction, which has been widely developed compared to microwave or enzymatic extractions, which should be studied in depth, including their combinations. After extraction, pomegranate peel byproducts (in the form of powders, liquid extracts, and/or encapsulated, among others) have been incorporated into several food matrixes, as a good tool to preserve ‘clean label’ foods without altering their composition and improving their functional properties. Future studies must clearly evaluate the energy efficiency/consumption, the cost, and the environmental impact leading to the sustainable extraction of the key bio-compounds. Moreover, predictive models are needed to optimize the phytochemical extraction and to help in decision-making along the supply chain.

Microwave-Assisted Hydrothermal Carbonization of Pomegranate Peels into Hydrochar for Environmental Applications

Several studies have reported that the hydrothermal carbonization method (HTC) of agricultural waste is able to produce a solid residue with interesting properties for the adsorption of organic pollutants from contaminated water. This work represents a facile method to prepare hydrochar (HC) from pomegranate peels’ waste using the microwave-assisted hydrothermal carbonization method (MHTC) at 200 °C for 1 h with a mass ratio of peel to water = 1:10. Activated hydrochar (AHC) was prepared by in situ chemical activation using ZnCl2 and MHTC. Several techniques have been applied to characterize the prepared samples as FTIR, XRD, TEM and SEM. The samples were investigated for their possible use as adsorbents of methylene blue (MB) dye. The results confirm the formation of amorphous hydrochar with a porous structure. The pH of zero point charge (pHzpc) is 4.3 and 4.6 for HC and AHC samples, respectively. The maximum adsorption capacity of HC and AHC samples are 194.9 and 12.55 mg/g (i.e., mg of adsorbate/g of adsorbent), respectively.