Investigation of the mechanisms of using metal complexation and cellulose nanofiber/sodium alginate layer-by-layer coating for retaining anthocyanin pigments in thermally processed blueberries in aqueous media

Application progress of nanocellulose in food packaging: A review

With the increasing environmental and ecological problems caused by petroleum-based packaging materials, the focus has gradually shifted to natural resources for the preparation of functional food packaging materials. In addition to biodegradable properties, nanocellulose (NC) mechanical properties, and rich surface chemistry are also fascinating and desired to be one of the most probable green packaging materials. In this review, we firstly introduce the recent progress of novel applications of NC in food packaging, including intelligent packaging, nano(bio)sensors, and nano-paper; secondly, we focus on the modification techniques of NC to summarize the properties (antimicrobial, mechanical, hydrophobic, antioxidant, and so on) that are required for food packaging, to expand the new synthetic methods and application areas. After presenting all the latest advances related to material design and sustainable applications, an overview summarizing the safety of NC is presented to promote a continuous and healthy movement of NC toward the field of truly sustainable packaging.

Metallophenolomics: A Novel Integrated Approach to Study Complexation of Plant Phenolics with Metal/Metalloid Ions

Plant adaptive strategies have been shaped during evolutionary development in the constant interaction with a plethora of environmental factors, including the presence of metals/metalloids in the environment. Among adaptive reactions against either the excess of trace elements or toxic doses of non-essential elements, their complexation with molecular endogenous ligands, including phenolics, has received increasing attention. Currently, the complexation of phenolics with metal(loid)s is a topic of intensive studies in different scientific fields. In spite of the numerous studies on their chelating capacity, the systemic analysis of phenolics as plant ligands has not been performed yet. Such a systematizing can be performed based on the modern approach of metallomics as an integral biometal science, which in turn has been differentiated into subgroups according to the nature of the bioligands. In this regard, the present review summarizes phenolics–metal(loid)s’ interactions using the metallomic approach. Experimental results on the chelating activity of representative compounds from different phenolic subgroups in vitro and in vivo are systematized. General properties of phenolic ligands and specific properties of anthocyanins are revealed. The novel concept of metallophenolomics is proposed, as a ligand-oriented subgroup of metallomics, which is an integrated approach to study phenolics–metal(loid)s’ complexations. The research subjects of metallophenolomics are outlined according to the methodology of metallomic studies, including mission-oriented biometal sciences (environmental sciences, food sciences and nutrition, medicine, cosmetology, coloration technologies, chemical sciences, material sciences, solar cell sciences). Metallophenolomics opens new prospects to unite multidisciplinary investigations of phenolic–metal(loid) interactions.

Enhancing anthocyanin-phenolic copigmentation through epicarp layer treatment and edible coatings to retain anthocyanins in thermally processed whole blueberries

Anthocyanins in processed fruit degrade significantly due to their heat and oxygen sensitivity and water solubility. Copigmentation for stabilizing anthocyanins is less effective for whole fruit due to anthocyanins' location within cell vacuoles surrounded by the epicarp layer as barrier to prevent copigment complexing with anthocyanins. This study investigated strategies for enhancing anthocyanin-phenolic copigmentation on blueberry surface, and integrated copigmentation with layer-by-layer (LBL) coating to retain anthocyanin stability in thermally processed blueberries. Results indicated that epicarp layer treatment of fruit by Tween 80 (T80) and CaCl₂ is important for enhancing anthocyanin-phenolic copigmentation. The sequential copigmentation treatment using T80, ferulic acid, and CaCl₂ (T80→FA→CaCl₂ ) or T80, tannic acid, and CaCl₂ (T80→TA→CaCl₂ ) resulted in higher (p < 0.05) retention of total monomeric anthocyanin (3.18 mg/g and 3.38 mg/g, respectively) in thermally processed blueberries after 7-day ambient storage than that of untreated fruit (2.79 mg/g). Percent polymeric color (PPC) of blueberries treated by T80→FA→CaCl₂ (15.5%) or T80→TA→CaCl₂ (17.4%) was lower (p < 0.05) than that treated by TA alone (22.5%). The LBL coating enhanced microstructure stability for preserving anthocyanins in thermally processed blueberries. This study demonstrated the effectiveness of sequential copigmentation of blueberries after epicarp layer treatment followed by LBL coating for enhancing anthocyanin stability in processed whole fruit. PRACTICAL APPLICATION: When anthocyanin-rich fruit is thermally processed, anthocyanins degrade and leach to aqueous packing solution because of its heat sensitivity and water solubility. This study developed an innovative technology through implementing sequential treatments of copigmentation and water- and heat-resistant coating for preventing heat and water degradation of anthocyanins in whole fruit during processing in aqueous media. The developed technology can be practically applied to enhance the quality and health benefits of thermally processed anthocyanin-rich whole fruit. The technology can not only be utilized to improve existing fruit products, but also develop new and novel fruit products.

A comprehensive review of food gels: formation mechanisms, functions, applications, and challenges

Gels refer to the soft and flexible macromolecular polymeric materials retaining a large amount of water or biofluids in their three-dimensional network structure. Gels have attracted increasing interest in the food discipline, especially proteins and polysaccharides, due to their good biocompatibility, biodegradability, nutritional properties, and edibility. With the advancement of living standards, people's demand for nutritious, safe, reliable, and functionally diverse food and even personalized food has increased. As a result, gels exhibiting unique advantages in food application will be of great significance. However, a comprehensive review of functional hydrogels as food gels is still lacking. Here, we comprehensively review the gel-forming mechanisms of food gels and systematically classify them. Moreover, the potential of hydrogels as functional foods in different types of food areas is summarized, with a special focus on their applications in food packaging, satiating gels, nutrient delivery systems, food coloring adsorption, and food safety monitoring. Additionally, the key scientific issues for future food gel research, with specific reference to future novel food designs, mechanisms between food components and matrices, food gel-human interactions, and food gel safety, are discussed. Finally, the future directions of hydrogels for food science and technology are summarized.

Nanocellulose for Paper and Textile Coating: The Importance of Surface Chemistry

Nanocellulose has received enormous scientific interest for its abundance, easy manufacturing, biodegradability, and low cost. Cellulose nanocrystals (CNCs) and cellulose nanofibers (CNFs) are ideal candidates to replace plastic coating in the textile and paper industry. Thanks to their capacity to form an interconnected network kept together by hydrogen bonds, nanocelluloses perform an unprecedented strengthening action towards cellulose- and other fiber-based materials. Furthermore, nanocellulose use implies greener application procedures, such as deposition from water. The surface chemistry of nanocellulose plays a pivotal role in influencing the performance of the coating: tailored surface functionalization can introduce several properties, such as gas or grease barrier, hydrophobicity, antibacterial and anti-UV behavior. This review summarizes recent achievements in the use of nanocellulose for paper and textile coating, evidencing critical aspects of coating performances related to deposition technique, nanocellulose morphology, and surface functionalization. Furthermore, beyond focusing on the aspects strictly related to large-scale coating applications for paper and textile industries, this review includes recent achievements in the use of nanocellulose coating for the safeguarding of Cultural Heritage, an extremely noble and interesting emerging application of nanocellulose, focusing on consolidation of historical paper and archaeological textile. Finally, nanocellulose use in electronic devices as an electrode modifier is highlighted.

Layer-by-Layer Coating of Single-Cell Lacticaseibacillus rhamnosus to Increase Viability Under Simulated Gastrointestinal Conditions and Use in Film Formation

Probiotics and prebiotics are widely used as functional food ingredients. Viability of probiotics in the food matrix and further in the digestive system is still a challenge for the food industry. Different approaches were used to enhance the viability of probiotics including microencapsulation and layer-by-layer cell coating. The of aim of this study was to evaluate the viability of coated Lacticaseibacillus rhamnosus using a layer-by-layer (LbL) technique with black seed protein (BSP) extracted from Nigella sativa defatted seeds cakes (NsDSC), as a coating material, with alginate, inulin, or glucomannan, separately, and the final number of coating layers was 3. The viable cell counts of the plain and coated L. rhamnosus were determined under sequential simulated gastric fluid (SGF) for 120 min and simulated intestinal fluid (SIF) for 180 min. Additionally, the viability after exposure to 37, 45, and 55°C for 30 min was also determined. Generally, the survivability of coated L. rhamnosus showed significant (p ≤ 0.05) improvement (<4, 3, and 1.5 logs reduction for glucomannan, alginate and inulin, respectively) compared with plain cells (∼6.7 log reduction) under sequential exposure to SGF and SIF. Moreover, the cells coated with BSP and inulin showed the best protection for L. rhamnosus under high temperatures. Edible films prepared with pectin with LbL-coated cells showed significantly higher values in their tensile strength (TS) of 50% and elongation at the break (EB) of 32.5% than pectin without LbL-coated cells. The LbL technique showed a significant protection of probiotic cells and potential use in food application.

A comprehensive review on innovative and advanced stabilization approaches of anthocyanin by modifying structure and controlling environmental factors

Anthocyanins are pigments abundant in fruits and vegetables, and commonly applied in foods due to attractive colour and health-promoting benefits. However, instability of anthocyanins leads to their easy degradation, reduced bioactivity, and colour fading in food processing, limiting their application and causing economic losses. Stability of anthocyanins depends on their own structures and environmental factors. For structural factors, modification including copigmentation, acylation and biosynthesis is a potential solution to increase anthocyanin stability due to forming stable structures. With regard to environmental factors, encapsulation such as microencapsulation, liposome and nanoparticles has been shown effectively to enhance the stability. We proposed the potential challenges and perspectives for the diversification of anthocyanin-rich products for food application, particularly, introduction of hazards, technical limitations, interaction with other ingredients in food system and exploration of pyranoanthocyanins. The integrated strategies are warranted for improving anthocyanin stabilization for promoting their further application in food industry.

Combination of copigmentation and encapsulation strategies for the synergistic stabilization of anthocyanins

Copigmentation and encapsulation are the two most commonly used techniques for anthocyanin stabilization. However, each of these techniques by itself suffers from many challenges associated with the simultaneous achievement of color intensification and high stability of anthocyanins. Integrating copigmentation and encapsulation may overcome the limitation of usage of a single technique. This review summarizes the most recent studies and their challenges aiming at combining copigmentation and encapsulation techniques. The effective approaches for encapsulating copigmented anthocyanins are described, including spray/freeze-drying, emulsification, gelation, polyelectrolyte complexation, and their combinations. Other emerging approaches, such as layer-by-layer deposition and ultrasonication, are also reviewed. The physicochemical principles underlying the combined strategies for the fabrication of various delivery systems are discussed. Particular emphasis is directed toward the synergistic effects of copigmentation and encapsulation, for example, modulating roles of copigments in the processes of gelation and complexation. Finally, some of the major challenges and opportunities for future studies are highlighted. The trend of integrating copigmentation and encapsulation has been just started to develop. The information in this review should facilitate the exploration of the combination of multistrategy and the fabrication of robust delivery systems for copigmented anthocyanins.

Highly Transparent, Strong, and Flexible Films with Modified Cellulose Nanofiber Bearing UV Shielding Property

This work investigates multifunctional composite films synthesized with cellulose nanofibers (CNFs) and poly(vinyl alcohol) (PVA). First, TEMPO-oxidized CNFs were modified in the heterogeneous phase with benzophenone, diisocyanate, and epoxidized soybean oil via esterification reactions. A thorough characterization was carried out via elemental analysis as well as FT-IR and X-ray photoelectron spectroscopies and solid-state NMR. Following, the surface-modified CNFs were combined with PVA to endow composite films with UV-absorbing capabilities while increasing their thermomechanical strength and maintaining a high light transmittance. Compared to neat PVF films, the tensile strength, Young modulus, and elongation of the films underwent dramatic increases upon addition of the reinforcing phase (maximum values of ∼96 MPa, ∼ 714 MPa, and ∼350%, respectively). A high UV blocking performance, especially in the UVB region, was observed for the introduced multifunctional PVA films at CNF loadings below 5 wt %. The trade-off between modified nanofibril function as interfacial reinforcement and aggregation leads to an optimum loading. The results indicate promising applications, for example, in active packaging.

Novel Biobased Sodium Shellac for Wrapping Disperse Multiscale Emulsion Particles

As a result of amphipathic oligomers driven by different forces including hydrophobic interaction, electrostatic interaction, H-bond, and heat, multiscale emulsion particles can be wrapped. In this paper we attempted to use sodium shellac as a novel biobased wrapping material. The H⁺, Ca⁺, and spray-drying methods were employed to solidify the complex vitamin E (VE) emulsion with sodium shellac to fabricate the beads. The VE loading and encapsulation efficiency were used to evaluate the wrapping process. The results show that the microscale VE emulsion particles could easily be wrapped by these three means. However, due to the high solid content of the nanoscale emulsion particles, it was difficult to wrap them by spray-drying method. The beads solidified by H⁺ had higher VE loading and encapsulation efficiency than those solidified by other methods and even grabbed the hydrophobic molecule VE from the emulsion micelles. At an R_VS of 1:4, these two parameters, which are obtained by the nanoscale emulsion particle wrapping process, could reach 18.9 and 64.3% supported by the single driving force of hydrophobic interaction. Above all, this research introduced a novel wrapping material driven by different forces that can aggregate and wrap the emulsion micelles. It can be widely used in the medical, food, and cosmetics industries.

Porous Cellulose Microgel Particle: A Fascinating Host for the Encapsulation, Protection, and Delivery of Lactobacillus plantarum

Advances in probiotic markets are always restrained by a low viable loading capacity and poor viability. Herein, cellulose microgels (CMs) with high porosity of 95.83 ± 0.38%, prepared by the sol-gel transition method, turned out to be a hospitable host that accommodated a large number of viable Lactobacillus plantarum higher than 10(9) colony-forming units (cfu)/g. The unique porous structure fascinated probiotics to penetrate into the core of microgels. The conjugation with alginate helped for better acid resistance and bacterial survival of the probiotics. In comparison to Ca-alginate gels, core-shell gels showed sustainable release of L. plantarum cells without damage of viability, lasting for 360 min in simulated intestine fluid. The cellulose host helped to sustain the viable cell release for a longer duration and afford better shelter for L. plantarum cells as a result of the porous structure and rigid supporting property. The core-shell gels are promising for constructing targeted delivery vehicles of bioactive nutrients.