Physical, structural and antioxidant properties of brewer's spent grain protein films

A straight-forward fabrication of yuba films with controllable mechanical properties by oil-in-water emulsion model system rather than soymilk

The traditional process of producing yuba films from soybeans strictly limits the development of its industrial production due to the numerous processes and intricate procedures involved. In this study, a straight-forward and effective strategy was proposed to substitute soymilk with an emulsion made from soybean protein isolate and soybean oil for the formation of yuba films. It was found that the mechanical properties of yuba films formed through this method were controlled by the concentrations of proteins and oils. As the protein concentrations increased, a higher ratio of adsorbed proteins adhered to the surface of oil droplets, which in turn facilitated the recombination of proteins and the formation of larger aggregates during heat incubation. The rheological properties and interfacial adsorption behavior suggested that larger protein aggregates exhibited a greater diffusion rate and were more prone to unfolding and re-crosslinking at the interface through heat induction, resulting in the formation of stronger protein networks. Confocal laser scanning microscope images revealed a notable increase in the density of oil distribution within the yuba films as the oil concentrations in the pre-emulsion rose. Combined with the dense protein network formed at high protein concentrations, the elongation of yuba films was significantly increased.

Impact of soybean protein isolate concentration on chitosan-cellulose nanofiber edible films: Focus on structure and properties

Chitosan and cellulose nanofiber films are frequently employed as biodegradable materials for food packaging. However, many exhibit suboptimal hydrophobicity and antioxidant properties. To address these shortcomings, we enhanced the performance by adding different concentrations of soybean protein isolate (SPI) to chitosan-cellulose nanofiber (CS-CNF) films. As SPI concentration varied, the turbidity, particle size, and ζ-potential of the film-forming solutions initially decreased and subsequently increased. This suggests that 1 % SPI augments the electrostatic attraction and compatibility. Rheological analysis confirmed a pronounced apparent viscosity at this concentration. Analyses using Fourier transform infrared spectra, Raman spectra, X-ray diffraction, and Scanning electron microscope revealed the presence of hydrogen bonds and electrostatic interactions between SPI and CS-CNF, indicative of superior compatibility. When SPI concentration was set at 1 %, notable enhancements in film attributes were observed: improvements in tensile strength and elongation at break, a reduction in water vapor permeability by 8.23 %, and an elevation in the contact angle by 18.85 %. Furthermore, at this concentration, the ABTS+ and DPPH scavenging capacities of the film surged by 61.53 % and 46.18 %, respectively. Meanwhile, the films we prepare are not toxic. This research offers valuable insights for the advancement and application of protein-polysaccharide-based films.

Incorporation of cinnamaldehyde, carvacrol, and eugenol into zein films for active food packaging: enhanced mechanical properties, antimicrobial activity, and controlled release

Active packaging with antimicrobial functions to improve the quality and extend the shelf life of food products has gained great interest. Because commercial plastic packaging materials are not biodegradable and cause great environmental problems, plant-derived natural materials have been widely studied for the application of biodegradable packaging materials. Herein, we reported a study of essential oils (EOs)-loaded zein film. Cinnamaldehyde (CIN), carvacrol, and eugenol were added to equip the films with antimicrobial effects, while polyethylene glycol (PEG) and oleic acid (OA) were selected for the improvements of mechanical properties. The results showed that PEG efficiently improves the tensile strength and elongation (%E) of zein films compared to OA, although PEG induced weaker water barrier properties of the films than OA. FTIR spectra confirmed the formation of the hydrogen bonds between zein and PEG/OA. The EO-embedded zein film showed better antimicrobial effects than EO themselves. CIN-embedded films showed the highest antimicrobial effect among the three EOs. The sizes of the inhibition zones against Staphylococcus aureus of PEG-added zein films with 1%, 3%, and 5% CIN were 5.67, 12.67, and 16.67 mm, which were larger than that of pure CIN, with the sizes of 0.00, 3.00, and 4.67 mm, respectively. The developed films demonstrate a gradual release of EOs and show antimicrobial effects up to 96 h, indicating their high potential for the applications as active food packaging.

Review of the valorization initiatives of brewing and distilling by-products

Beer and spirits are two of the most consumed alcoholic beverages in the world, and their production generates enormous amounts of by-product materials. This ranges from spent grain, spent yeast, spent kieselguhr, trub, carbon dioxide, pot ale, and distilled gin spent botanicals. The present circular economy dynamics and increased awareness on resource use for enhanced sustainable production practices have driven changes and innovations in the management practices and utilization of these by-products. These include food product development, functional food applications, biotechnological applications, and bioactive compounds extraction. As a result, the brewing and distilling sector of the food and drinks industry is beginning to see a shift from conventional uses of by-products such as animal feed to more innovative applications. This review paper therefore explored some of these valorization initiatives and the current state of the art.

Foaming properties are improved by interactions between brewer's spent grain proteins and carrageenans in aqueous solution

BACKGROUND

Foaming properties and macromolecular interactions in solution among brewer's spent grain proteins (CP) and iota and lambda carrageenans (i-CG and l-CG, respectively) as a function of aqueous medium pH (2-6) and protein-polysaccharide ratio, R_CP:CG (1:1, 2:1 and 4:1), were studied. At these conditions, the CP colloidal stability was favored by the formation of soluble electrostatic complexes with CG. Fluorescence (intrinsic and extrinsic) spectroscopy and dynamic light scattering techniques, including particle size and ζ-potential analysis, were applied to know the phase behavior of the biopolymer systems. The bubbling method was used to produce foams, and the foam expansion (%) and half-life time (t_1/2 ) were determined.

RESULTS

Both CG promoted an increased Trp fluorescence emission depending on the pH, suggesting conformational changes in CP. The CG in mixed systems produced a significant decrease in the extrinsic fluorescence intensity, mainly at low pH values, highlighting a reduction in CP surface hydrophobicity. At the examined pH range, the ζ-potential values for mixed-systems were negative, and their magnitudes were intermediate between CP and CG, revealing the associative electrostatic nature of biopolymer interactions, which were dependent on the R_CP:CG . The particle size analysis confirmed the formation of soluble electrostatic complexes in solution. Finally, using i-CG at pH 2 or 3 and 2:1 R_CP:CG , the best foaming properties for mixed systems were observed.

CONCLUSION

The formation of electrostatic complexes with a compact assembly among biopolymers, high negative net charge, and colloidal stability convert the CP-CG mixed solutions into promising biopolymer systems for food foams production. © 2022 Society of Chemical Industry.

Novel linezolid loaded bio-composite films as dressings for effective wound healing: experimental design, development, optimization, and antimicrobial activity

Biphasic release bio-composite films of the low water-soluble drug, linezolid (LNZ), were formulated using the solvent casting technique. Different polymers and plasticizers (gelatin, Tween 80, polyethylene glycol 400, and glycerol) were assessed for the preparation of bio-composite films. An I-optimal design was applied for the optimization and to study the impact of polymer concentration (X₁), plasticizer concentration (X₂), polymer type (X₃), and plasticizer type (X₄) on different LNZ-loaded bio-composite films. The film thickness, moisture content, mechanical properties, swelling index, and percentage of drug release at fixed times opted as dependent variables. Results demonstrated a significant effect of all independent variables on the drug release from the prepared bio-composite films. The plasticizer concentration significantly increased the thickness, moisture content, elongation at break, swelling index, and in vitro drug release and significantly reduced the tensile strength. The optimized LNZ-loaded bio-composite film comprised of 15% Tween 80 and 30% PEG 400 was highly swellable, elastic, acceptable tensile properties, safe, maintained a moist environment, and indicated great antimicrobial activity against both Staphylococcus aureus (ATCC^® 25922) and methicillin-resistant Staphylococcus aureus (MRSA), which are common wound infectious bacteria. The present study concludes that the optimized LNZ-loaded bio-composite film was successfully designed with fast drug release kinetics and it could be regarded as a promising novel antimicrobial wound dressing formulation.

The Potential of Brewer’s Spent Grain in the Circular Bioeconomy: State of the Art and Future Perspectives

Brewer’s spent grain (BSG) accounts for approximately 85% of the total mass of solid by-products in the brewing industry and represents an important secondary raw material of future biorefineries. Currently, the main application of BSG is limited to the feed and food industry. There is a strong need to develop sustainable pretreatment and fractionation processes to obtain BSG hydrolysates that enable efficient biotransformation into biofuels, biomaterials, or biochemicals. This paper aims to provide a comprehensive insight into the availability of BSG, chemical properties, and current and potential applications juxtaposed with the existing and emerging markets of the pyramid of bio-based products in the context of sustainable and circular bioeconomy. An economic evaluation of BSG for the production of highly valuable products is presented in the context of sustainable and circular bioeconomy targeting the market of Central and Eastern European countries (BIOEAST region).

The Food-Materials Nexus: Next Generation Bioplastics and Advanced Materials from Agri-Food Residues

The most recent strategies available for upcycling agri-food losses and waste (FLW) into functional bioplastics and advanced materials are reviewed and the valorization of food residuals are put in perspective, adding to the water-food-energy nexus. Low value or underutilized biomass, biocolloids, water-soluble biopolymers, polymerizable monomers, and nutrients are introduced as feasible building blocks for biotechnological conversion into bioplastics. The latter are demonstrated for their incorporation in multifunctional packaging, biomedical devices, sensors, actuators, and energy conversion and storage devices, contributing to the valorization efforts within the future circular bioeconomy. Strategies are introduced to effectively synthesize, deconstruct and reassemble or engineer FLW-derived monomeric, polymeric, and colloidal building blocks. Multifunctional bioplastics are introduced considering the structural, chemical, physical as well as the accessibility of FLW precursors. Processing techniques are analyzed within the fields of polymer chemistry and physics. The prospects of FLW streams and biomass surplus, considering their availability, interactions with water and thermal stability, are critically discussed in a near-future scenario that is expected to lead to next-generation bioplastics and advanced materials.

Protein-Based Films and Coatings for Food Industry Applications

Food packaging is an area of interest not just for food producers or food marketing, but also for consumers who are more and more aware about the fact that food packaging has a great impact on food product quality and on the environment. The most used materials for the packaging of food are plastic, glass, metal, and paper. Still, over time edible films have become widely used for a variety of different products and different food categories such as meat products, vegetables, or dairy products. For example, proteins are excellent materials used for obtaining edible or non-edible coatings and films. The scope of this review is to overview the literature on protein utilization in food packages and edible packages, their functionalization, antioxidant, antimicrobial and antifungal activities, and economic perspectives. Different vegetable (corn, soy, mung bean, pea, grass pea, wild and Pasankalla quinoa, bitter vetch) and animal (whey, casein, keratin, collagen, gelatin, surimi, egg white) protein sources are discussed. Mechanical properties, thickness, moisture content, water vapor permeability, sensorial properties, and suitability for the environment also have a significant impact on protein-based packages utilization.

Brewer’s Spent Grains: Possibilities of Valorization, a Review

This review was based on updated research on how to use brewer’s spent grains (BSG). The use of BSG was considered both in food, as an ingredient or using value-added components derived from brewer’s spent grain, or in non-food products such as pharmaceuticals, cosmetics, construction, or food packaging. BSG is a valuable source of individual components due to its high nutritional value and low cost that is worth exploiting more to reduce food waste but also to improve human health and the environment. From the bioeconomy point of view, biological resources are transformed into bioenergetically viable and economically valuable products. The pretreatment stage of BSG biomass plays an important role in the efficiency of the extraction process and the yield obtained. The pretreatments presented in this review are both conventional and modern extraction methods, such as solvent extractions or microwave-assisted extractions, ultrasonic-assisted extractions, etc.