Functional evaluation of microencapsulated anthocyanins from sour cherries skins extract in whey proteins isolate

Cross-Linked Microencapsulation of CO2 Supercritical Extracted Oleoresins from Sea Buckthorn: Evidence of Targeted Functionality and Stability

Oleoresin supercritical extracts from sea buckthorn were microencapsulated in whey proteins isolate and casein, in two states: native (N) and cross-linked mediated by transglutaminase (TG). The encapsulation efficiency showed values higher than 92% for total carotenoids and lycopene. Phytochemicals content was 352.90 ± 1.02 mg/g dry weight (DW) for total carotenoids in TG and 302.98 ± 2.30 mg/g DW in N, with antioxidant activity of 703.13 ± 23.60 mMol Trolox/g DW and 608.74 ± 7.12 mMol Trolox/g DW, respectively. Both powders had an inhibitory effect on α-glucosidase, of about 40% for N and 35% for TG. The presence of spherosomes was highlighted, with sizes ranging between 15.23-73.41 µm and an agglutination tendency in N, and lower sizes, up to 35 µm in TG. The in vitro digestibility revealed a prolonged release in an intestinal environment, up to 65% for TG. Moisture sorption isotherms were studied at 20 °C and the shape of curves corresponds to sigmoidal type II model. The presence of cross-linked mediated aggregates in TG powders improved stability and flowability. Our results can be used as evidence that cross-linked aggregates mediated by transglutaminase applied for microencapsulation of oleoresins have the potential to become new delivery systems, for carotenoids and lycopene, being valuable in terms of their attractive color and biological and bioaccessibility properties.

Co-Microencapsulation of Anthocyanins from Cornelian Cherry Fruits and Lactic Acid Bacteria in Biopolymeric Matrices by Freeze-Drying: Evidences on Functional Properties and Applications in Food

Cornus mas was used in this study as a rich source of health-promoting bioactives. The cornelian cherries were used to extract the polyphenols and anthocyanins. The chromatographic profile of the Cornus mas fruit extract revealed the presence of several anthocyanins, mainly delphinidin, cyanidin and pelargonidin glycosides. The extract was co-microencapsulated with Lactobacillus casei ssp. paracasei in a unique combination of whey protein isolates, inulin and chitosan by freeze-drying, with an encapsulation efficiency of 89.16 ± 1.23% for anthocyanins and 80.33 ± 0.44% for lactic acid bacteria. The pink-red colored powder showed a total anthocyanins content of 19.86 ± 1.18 mg cyanidin-3-glucoside/g dry weight (DW), yielding an antioxidant activity of 54.43 ± 0.73 mMol Trolox/g DW. The viable cells were 9.39 × 10⁹ colony forming units (CFU)/g DW. The confocal microscopy analysis revealed the microencapsulated powder as a complex one, with several large formations containing smaller aggregates, consisting of the lactic acid bacteria cells, the cornelian cherries’ bioactive compounds and the biopolymers. The powder was tested for stability over 90 days, showing a decrease of 50% in anthocyanins and 37% in flavonoids content, with no significant changes in antioxidant activity and CFU. The powder showed a significant inhibitory effect against the α-amylase of 89.72 ± 1.35% and of 24.13 ± 0.01% for α-glucosidase. In vitro digestibility studies showed a significant release of anthocyanins in gastric juice, followed by a decrease in intestinal simulated conditions. The functional properties of the powder were tested by addition into a yogurt, highlighting a higher and more stable antioxidant activity at storage when compared to the control.

Co-Microencapsulation of Anthocyanins from Black Currant Extract and Lactic Acid Bacteria in Biopolymeric Matrices

Anthocyanins from black currant extract and lactic acid bacteria were co-microencapsulated using a gastro-intestinal-resistant biocomposite of whey protein isolate, inulin, and chitosan, with an encapsulation efficiency of 95.46% ± 1.30% and 87.38% ± 0.48%, respectively. The applied freeze-drying allowed a dark purple stable powder to be obtained, with a satisfactory content of phytochemicals and 11 log colony forming units (CFU)/g dry weight of powder (DW). Confocal laser microscopy displayed a complex system, with several large formations and smaller aggregates inside, consisting of biologically active compounds, lactic acid bacteria cells, and biopolymers. The powder showed good storage stability, with no significant changes in phytochemicals and viable cells over 3 months. An antioxidant activity of 63.64 ± 0.75 mMol Trolox/g DW and an inhibitory effect on α-amylase and α-glucosidase of 87.10% ± 2.08% and 36.96% ± 3.98%, respectively, highlighted the potential biological activities of the co-microencapsulated powder. Significantly, the in vitro digestibility profile showed remarkable protection in the gastric environment, with controlled release in the intestinal simulated environment. The powder was tested by addition into a complex food matrix (yogurt), and the results showed satisfactory stability of biologically active compounds when stored for 21 d at 4 °C. The obtained results confirm the important role of microencapsulation in ensuring a high degree of protection, thus allowing new approaches in developing food ingredients and nutraceuticals, with enhanced functionalities.

Anthocyanins: New techniques and challenges in microencapsulation

Anthocyanins are a bioactive compound belonging to the flavonoid classthatis present in human nutrition through plant-based foods. Due to their antioxidant properties, several health benefits related to their consumption are reported in the literature. The stability of the color and the properties of anthocyanins is strongly affected by pH, solvent, temperature, and other environmental conditions. In addition, the insufficient residence time of anthocyanins in the upper digestive tract causes apartialabsorption, which needs to be improved. These factshave led researchers to investigate new forms of processing that provide minimal degradation. Microencapsulation is a promising possibility to stabilize anthocyanin extracts and allow their addition to food products in a more stable form. The microcapsules can still provide a prolonged gastrointestinal retention time caused by the improvement of the bioadhesive properties in the mucus covering the intestinal epithelium. Although there are efficient and emerging techniques, anthocyanins microencapsulation is still a challenge for the food industry. The purpose of this work is to provide an overview of anthocyanins structure, absorptionand protection, and to show the main conventional and emerging microencapsulation methods and their pros and cons.

New Functional Ingredients Based on Microencapsulation of Aqueous Anthocyanin-Rich Extracts Derived from Black Rice (Oryza sativa L.)

The aqueous anthocyanin-rich extract derived from black rice (Oryza sativa L.) was encapsulated by freeze drying using milk proteins and peptides as coating materials. The molecular modelling approach indicated that all major casein fractions and whey proteins were able to bind at least one anthocyanin molecule. The hydrophobic interactions and hydrogen bonding across the interfaces appeared to be mainly responsible for the stabilizations of the complexes formed between the coating material and bioactive compounds. Two dark purple colored powders, differentiated by the ratio of the encapsulation materials used, rich in phytochemicals were obtained, with an encapsulation efficiency of up to 99%. The powders were tested for antioxidant activity, cytocompatibility, and thermal stability. The morphological structure of the powders highlighted the presence of encapsulated anthocyanins. Both powders showed a remarkable antioxidant activity of about 46 mM Trolox/g D.W., and cytocompatibility on the L929 fibroblast culture. At certain concentrations, both powders stimulated cell proliferation. The powders showed a good thermal stability between 75 and 100 °C for 15 min. The powders were tested in a food model system and checked for stability of phytochemicals during storage. The added value of the powders was demonstrated throughout the antioxidant activity, which remained unchanged during storage.

Valorizations of Sweet Cherries Skins Phytochemicals by Extraction, Microencapsulation and Development of Value-Added Food Products

Sweet cherries are processed in various ways, leading to significant amounts of underutilized by-products that can potentially be used as a source of bioactive compounds, including antioxidants. The present study focuses on identifying ways to exploit bioactive compounds from sweet cherry skins, namely the extraction, microencapsulation, and functionalizing of some food product to obtain added value. The anthocyanins from skins were extracted and encapsulated in a combination of whey proteins isolate and chitosan by freeze-drying, with an encapsulation efficiency of 77.68 ± 2.57%. The powder showed a satisfactory content in polyphenols, of which anthocyanins content was 14.48 ± 1.17 mg cyanidin 3-glucoside/100 g dry weight (D.W.) and antioxidant activity of 85.37 ± 1.18 µM Trolox/100 g D.W. The powder was morphologically analyzed, revealing the presence of coacervates, ranging in size from 12–54 μm, forming large spheresomes (up to 200 μm). The powder was used as a functional ingredient to develop two value-added food products, namely yoghurt and marshmallows. The powder was tested for its prebiotic effect on L. casei 431^® in the yoghurt samples during 21 days at 4 °C, when a decrease in viability was found, up to 6 log CFU·g⁻¹. The anthocyanins and antioxidant activity decreased in yoghurt and increased in marshmallows during storage time. The obtained results support the potential use of extracts from underutilized sources in the development of functional ingredients and value-added food products.

Interactions of flavonoids from yellow onion skins with whey proteins: Mechanisms of binding and microencapsulation with different combinations of polymers

The interaction of flavonoids extracted from yellow onion skins with whey proteins isolate was studied using fluorescence spectroscopy and simulation methods from the perspectives of microencapsulation. The fluorescence spectroscopy revealed a static quenching mechanism and the involvement of van der Waals and H bonding in complexes formation. The in silico methods suggested that the heat treatment of the major whey proteins affected the binding pockets and therefore the affinity for the main flavonoids. The interaction surface decreased and the interaction energy increased, suggesting lower binding strength. Further, the yellow onion skins extract was successfully encapsulated in whey proteins isolate and different combinations of polymers, including chitosan, maltodextrin and pectin by freeze drying. The resulted powder showed a total flavonoid content of 5.84 ± 0.23 mg quercetin equivalents/g DW in whey protein-chitosan combination and 104.97 ± 5.02 mg quercetin equivalents/g DW in whey protein-maltodextrin-pectin combinations, with antioxidant activity of 175.93 ± 1.50 mM mM Trolox/g DW and 269.20 ± 3.59 mM Trolox/g DW, respectively. The confocal microscopy indicated that the flavonoids aggregated inside the matrix formed between the whey proteins and various polymers and irregular and compact clusters. Therefore, a comprehensive approach involving the extraction of flavonoids from underutilized food by-products, such as yellow onion skins, evaluation of binding mechanisms with whey proteins, whereas tailoring their functional benefit through microencapsulation in order to obtain active ingredients are reported.

Advances in the Application of Microcapsules as Carriers of Functional Compounds for Food Products

Natural bioactive compounds and living cells have been reported as promising products with beneficial properties to human health. The constant challenge regarding the use of these components is their easy degradation during processing and storage. However, their stability can be improved with the microencapsulation process, in which a compound sensitive to adverse environmental conditions is retained within a protective polymeric material. Microencapsulation is a widely used methodology for the preservation and stabilization of functional compounds for food, pharmaceutical, and cosmetic applications. The present review discusses advances in the production and application of microcapsules loaded with functional compounds in food products. The main methods for producing microcapsules, as well as the classes of functional compounds and wall materials used, are presented. Additionally, the release of compounds from loaded microcapsules in food matrices and in simulated gastrointestinal conditions is also assessed.