Ivana Buljeta

This study investigated the potential of cellulose as a carrier for bioactive phenolic compounds from tart cherry juice. Using a freeze-drying method, encapsulates were prepared by varying cellulose content (2.5%, 5%, 7.5%, and 10%) and complexation times (15 and 60 min) while maintaining a constant juice volume. The prepared encapsulates were characterized by determining the concentrations of total phenols, monomeric anthocyanins, and proanthocyanidins, alongside antioxidant activity by spectrophotometric methods, individual polyphenols by HPLC, color parameters and structural changes via IR spectroscopy. Additionally, the stability of these parameters was evaluated after one year of storage at room temperature. Results indicated that the highest concentrations of phenolic compounds and the strongest antioxidant potential were achieved with 2.5% cellulose content (the lowest content) after 15 min of complexation (shorter time). Concentrations of polyphenols decreased as the cellulose contents increased. Although changes in chemical parameters occurred during storage, the results confirm that cellulose is a viable carrier for tart cherry phenolics, particularly at lower contents, offering a promising approach for formulating stable bioactive delivery systems.

Promising approach for the expansion of the functional food sector is combining various ingredients with potential health benefits. The aim of this study was to create protein aggregates by freeze-drying encapsulation. Rice or pea proteins were used as carriers for encapsulation of chokeberry juice polyphenols. Additionally, disaccharides (sucrose and trehalose) were added to explore possible enhancement of encapsulation of polyphenols. Two methods were employed for complexation of ingredients prior to freeze-drying: one based on complexation of all ingredients at the same time and the other on complexation first of proteins with disaccharides and then with chokeberry juice. All parameters affected the binding of polyphenols on proteins. Total polyphenols, proanthocyanidins, individual polyphenols, and antioxidant potentials of created protein aggregates were determined. When rice protein was the main carrier, the addition of disaccharides caused a decrease in total polyphenols and proanthocyanindins contents (22.41–24.01 mg GAE/g and 6.36–7.28 mg PB2E/g, respectively) in comparison to aggregates without their addition (28.03 mg GAE/g and 8.57 mg PB2E/g, respectively). In the case of pea proteins, a different trend was observed. Aggregates without disaccharide addition had a lower amount of total polyphenols and proanthocyanindins (21.25 mg GAE/g and 5.56 mg PB2E/g, respectively) than those with disaccharide addition (21.42–26.44 mg GAE/g and 6.37–9.45 mg PB2E/g, respectively). Interactions between compounds were proven through IR spectra, and they included changes in amid structures, as well as hydrogen bonds and hydrophobic interactions. Such formulated plant-based protein aggregates can be used in the food industry for the enrichment of foods with polyphenols, incensement of antioxidant potential, and prolonging stability of products.

Polyphenols receive special attention from consumers and researchers due to their proven health benefits. They are present in different plants, and chokeberries are one of the significant polyphenol sources. Polyphenols found in chokeberries belong to the groups of phenolic acids, anthocyanins, proanthocyanidins, flavonols and flavanols. The highest concentration found in chokeberries belongs to proanthocyanidins followed by anthocyanins. The analysis of polyphenols is very demanding due to the great diversity and presence of conjugated forms. So, development of sensitive, rapid, and accurate analytical methods for analysis of polyphenols is very important. Liquid chromatography is a promising technique for polyphenols analysis, especially one equipped with mass spectrometry that gives additional information about molecular mass and structure. In this review, relevant studies conducted on the analysis of chokeberry polyphenols are presented.

Dietary fibers and phenolic acids are recognized for their various health benefits; thus, cellulose was selected as a carrier polymer of phenolic acids, including gallic acid and caffeic acid. Dried cellulose particles were prepared through the complexation of different amounts of cellulose (2.5,...

The amount of waste generated by the production of food products has increased over the years, presenting economic and environmental problems. To minimize these problems, it is necessary to valorize food waste in order to explore its further utilization in the food industry and also in other industries. Such waste usually represents a valuable raw material in terms of dietary fibers or bioactive components. Dietary fibers, especially pectin, are usually derived from apple pomace or citrus peel. Currently, sources of dietary fibers include novel food waste streams and by-products. Also, the utilization of novel extraction techniques is in demand to limit conventional processes. This review provides information about the conventional and innovative extraction approaches for dietary fibers from different food wastes. The extraction of these fibers depends on the materials used and the extraction conditions, such as temperature, solvents, time, pH, and liquid/solid ratio. Novel green techniques may ensure an increase in fiber yield and better quality, as well as a reduction in operating time and toxic solvents.

Nowadays, the development of innovative food products with positive health effects is on the rise. Consequently, the aim of this study was a formulation of aggregates based on tart cherry juice and dairy protein matrix to investigate whether different amounts (2% and 6%) of protein matrix have an impact on the adsorption of polyphenols as well as on the adsorption of flavor compounds. Formulated aggregates were investigated through high-performance liquid chromatography, spectrophotometric methods, gas chromatography and Fourier transform infrared spectrometry. The obtained results revealed that with an increase in the amount of protein matrix used for the formulation of aggregates, a decrease in the adsorption of polyphenols occurred, and, consequently, the antioxidant activity of the formulated aggregates was lower. The amount of protein matrix additionally affected the adsorption of flavor compounds; thus the formulated aggregates differed in their flavor profiles in comparison with tart cherry juice. Adsorption of both phenolic and flavor compounds caused changes in the protein structure, as proven by recording IR spectra. Formulated dairy-protein-based aggregates could be used as additives which are enriched with tart cherry polyphenols and flavor compounds.

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.

Among flavonoids, quercetin has gained special attention due to its positive biological activities. Quercetin’s disadvantages, such as its hydrophobic nature, poor solubility, and permeability, could be overcome by complexation with different polymers. Dietary fibers are known as carriers of polyphenols, which can protect them from environmental conditions and thus allow them to be absorbed. In this study, apple and citrus fibers (as applicable food by-products) were used as carriers of quercetin. A constant amount of fibers (1%) and different concentrations of quercetin solution (5 mM, 10 mM, and 20 mM) were complexed. Obtained fiber aggregates were subjected to HPLC to determine the quercetin concentration and antioxidant activity of aggregates (ABTS, DPPH, FRAP, and CUPRAC assays). IR spectra were recorded to confirm complexation of quercetin with selected fibers, and an additional DSC study was performed to evaluate the thermal stability of fiber aggregates. The results of HPLC analysis showed that quercetin had higher affinity towards apple fiber than citrus fiber, without proportional trends of adsorption. Consequently, apple fiber aggregates had higher antioxidant potential than citrus fiber aggregates. FTIR-ATR analysis showed the formation of new bands and the loss of existing bands when quercetin was present. Adsorption of quercetin also had an impact on the thermal stability of formulated fiber aggregates. For apple fiber, this impact was negative, while for citrus fiber, the impact was positive. These results could contribute to greater understanding of quercetin’s behavior during the preparation of food additives based on polyphenols and fibers.

Polyphenols have received great attention as important phytochemicals beneficial for human health. They have a protective effect against cardiovascular disease, obesity, cancer and diabetes. The utilization of polyphenols as natural antioxidants, functional ingredients and supplements is limited due to their low stability caused by environmental and processing conditions, such as heat, light, oxygen, pH, enzymes and so forth. These disadvantages are overcome by the encapsulation of polyphenols by different methods in the presence of polyphenolic carriers. Different encapsulation technologies have been established with the purpose of decreasing polyphenol sensitivity and the creation of more efficient delivery systems. Among them, spray-drying and freeze-drying are the most common methods for polyphenol encapsulation. This review will provide an overview of scientific studies in which polyphenols from different sources were encapsulated using these two drying methods, as well as the impact of different polysaccharides used as carriers for encapsulation.

The objective of this study was to prepare hydrogels based on pectin and blackberry juice and additionally to fortify those hydrogels with apple fiber. For that purpose, two types of pectin (low methoxylated and high methoxylated) were used, and fortification was conducted with the addition of 10% of apple fiber. The hydrogels were evaluated for phenolic compounds, antioxidant activity and inhibition of α-glucosidase. In addition, the stability of these parameters after 8 months of storage was evaluated. Pectin type and addition of apple fiber had an impact on investigated parameters. Low methoxylated pectin hydrogels had a higher concentration of anthocyanins than high methoxylated pectin hydrogels, while the addition of apple fibers caused a decrease in anthocyanin content. However, fortified hydrogels had higher antioxidant activity due to the presence of phenolics from apple fibers. The results showed that anthocyanins were more favorable in inhibiting α-glucosidase because samples with higher anthocyanins concentration had lower IC₅₀ values. Obtained hydrogels can be used as intermediate products or ingredients (like fruit fillings or spreads) for the improvement or development of novel food products to increase their fiber content and antioxidant potential.