Effects of carbohydrate/protein ratio on the microstructure and the barrier and sorption properties of wheat starch-whey protein blend edible films

More than just a beer - Brewers' spent grain, spent hops, and spent yeast as potential functional fillers for polymer composites

Beer is among the most popular beverages in the world, with the production distributed uniformly between the biggest continents, so the utilization of brewing by-products is essential on a global scale. Among their potential recipients, the plastics industry offers extensive range of potential products. Herein, the presented study investigated the application of currently underutilized solid brewing by-products (brewers' spent grain, spent hops, spent yeast) as fillers for highly-filled poly(ε-caprolactone)-based composites, providing the first direct connection between spent hops or spent yeast and the polymer composites. Comprehensive by-product characterization revealed differences in chemical composition. The elemental C:O ratio, protein content, and Trolox equivalent antioxidant capacity varied from 1.40 to 1.89, 12.9 to 32.4 wt%, and 2.41 to 10.24 mg/g, respectively, which was mirrored in the composites' structure and performance. Morphological analysis pointed to the composition-driven hydrophilicity gap limiting interfacial adhesion for high shares of brewers' spent grain and spent hops, due to high hydrophilicity induced by carbohydrate content. Phytochemicals and other components of applied by-products stimulated composites' oxidative resistance, shifting oxidation onset temperature from 261 °C for matrix over 360 °C for high spent yeast shares. Simultaneously, spent yeast also provided compatibilizing effects for poly(ε-caprolactone)-based composites, reducing complex viscosity compared to other fillers and indicating its highest affinity to poly(ε-caprolactone)due to the lowest hydrophilicity gap. The presented results indicate that the proper selection of brewing by-products and adjustment of their shares creates an exciting possibility of engineering composites' structure and performance, which can be transferred to other polymers differing with hydrophilicity.

Innovative applications of whey protein for sustainable dairy industry: Environmental and technological perspectives-A comprehensive review

Industrial waste management is critical to maintaining environmental sustainability. The dairy industry (DI), as one of the major consumers of freshwater, generates substantial whey dairy effluent, which is notably rich in organic matter and thus a significant pollutant. The effluent represents environmental risks due to its high biological and chemical oxygen demands. Today, stringent government regulations, environmental laws, and heightened consumer health awareness are compelling industries to responsibly manage and reuse whey waste. Therefore, this study investigates sustainable solutions for efficiently utilizing DI waste. Employing a systematic review approach, the research reveals that innovative technologies enable the creation of renewable, high-quality, value-added food products from dairy byproducts. These innovations offer promising sustainable waste management strategies for the dairy sector, aligning with economic interests. The main objectives of the study deal with, (a) assessing the environmental impact of dairy sector waste, (b) exploring the multifaceted nutritional and health benefits inherent in cheese whey, and (c) investigating diverse biotechnological approaches to fashion value-added, eco-friendly dairy whey-based products for potential integration into various food products, and thus fostering economic sustainability. Finally, the implications of this work span theoretical considerations, practical applications, and outline future research pathways crucial for advancing the sustainable management of dairy waste.

Multi-Component Biodegradable Materials Based on Water Kefir Grains and Yeast Biomasses: Effect of the Mixing Ratio on the Properties of the Films

The use of biopolymeric materials is restricted for some applications due to their deficient properties in comparison to synthetic polymers. Blending different biopolymers is an alternative approach to overcome these limitations. In this study, we developed new biopolymeric blend materials based on the entire biomasses of water kefir grains and yeast. Film-forming dispersions with varying ratios of water kefir to yeast (100/0, 75/25, 50/50 25/75 and 0/100) underwent ultrasonic homogenisation and thermal treatment, resulting in homogeneous dispersions with pseudoplastic behaviour and interaction between both biomasses. Films obtained by casting had a continuous microstructure without cracks or phase separation. Infrared spectroscopy revealed the interaction between the blend components, leading to a homogeneous matrix. As the water kefir content in the film increased, transparency, thermal stability, glass transition temperature and elongation at break also increased. The thermogravimetric analyses and the mechanical tests showed that the combination of water kefir and yeast biomasses resulted in stronger interpolymeric interactions compared to single biomass films. The ratio of the components did not drastically alter hydration and water transport. Our results revealed that blending water kefir grains and yeast biomasses enhanced thermal and mechanical properties. These studies provided evidence that the developed materials are suitable candidates for food packaging applications.

Sustainable 3D Printing of Oral Films with Tunable Characteristics Using CMC-Based Inks from Durian Rind Wastes

With the growing interest in environmentally friendly and personalized medicines, new concept for combining three-dimensional printing (3DP) with natural-based biomaterials derived from agro-food wastes has emerged. This approach provides sustainable solutions for agricultural waste management and potential for developing of novel pharmaceutical products with tunable characteristics. This work demonstrated the feasibility of fabricating personalized theophylline films with four different structures (Full, Grid, Star, and Hilbert) using syringe extrusion 3DP and carboxymethyl cellulose (CMC) derived from durian rind wastes. Our findings suggested that all the CMC-based inks with shear thinning properties capable of being extruded smoothly through a small nozzle could potentially be used to fabricate the films with various complex printing patterns and high structural fidelity. The results also demonstrated that the film characteristics and release profiles could be easily modified by simply changing the slicing parameters (e.g., infill density and printing pattern). Amongst all formulations, Grid film, which was 3D-printed with 40% infill and a grid pattern, demonstrated a highly porous structure with high total pore volume. The voids between printing layers in Grid film increased theophylline release (up to 90% in 45 min) through improved wetting and water penetration. All findings in this study provide significant insight into how to modify film characteristics simply by digitally changing the printing pattern in slicer software without creating a new CAD model. This approach could help to simplify the 3DP process so that non-specialist users can easily implement it in community pharmacies or hospital on demand.

Effect of Cross-Linking Modification on Structural and Film-Forming Characteristics of Pearl Millet (Pennisetum glaucum L.) Starch

Pearl millet starch was modified using epichlorohydrin (EPI) at different concentrations (0.1%; 0.3%; 0.5%; and 0.8%) and evaluated for physicochemical, rheological, in vitro digestibility, and film-forming characteristics. The degree of cross-linking was observed at higher levels (0.5% and 0.8%) of EPI. Upon cross-linking, breakdown and setback viscosity reduced whereas pasting temperature was increased. Storage modulus (G′) and loss modulus (G″) value of cross-linked (CL) starches ranged between 2877 to 5744 Pa and 168 to 237 Pa, respectively, during the frequency sweep test. A drastic decrease was observed for steady shear (yield stress and consistency index) characteristics of CL starches. Resistant starch (RS) content was increased after starch modification, which imparts its nutritional values and starch modified at 0.8% had the highest RS content. Modifications of starch at different levels had significant effects on the moisture, opacity, solubility and mechanical properties of films. Outcomes of this study will be helpful to understand the properties of native and CL starches for their potential applications in preparation of edible films.

Application of Whey Protein-Based Edible Films and Coatings in Food Industries: An Updated Overview

The recent surge in environmental awareness and consumer demand for stable, healthy, and safe foods has led the packaging and food sectors to focus on developing edible packaging materials to reduce waste. Edible films and coatings as a modern sustainable packaging solution offer significant potential to serve as a functional barrier between the food and environment ensuring food safety and quality. Whey protein is one of the most promising edible biopolymers in the food packaging industry that has recently gained much attention for its abundant nature, safety, and biodegradability and as an ecofriendly alternative of synthetic polymers. Whey protein isolate and whey protein concentrate are the two major forms of whey protein involved in the formation of edible films and coatings. An edible whey film is a dry, highly interacting polymer network with a three-dimensional gel-type structure. Films/coatings made from whey proteins are colorless, odorless, flexible, and transparent with outstanding mechanical and barrier properties compared with polysaccharide and other-protein polymers. They have high water vapor permeability, low tensile strength, and excellent oxygen permeability compared with other protein films. Whey protein-based films/coatings have been successfully demonstrated in certain foods as vehicles of active ingredients (antimicrobials, antioxidants, probiotics, etc.), without considerably altering the desired properties of packaging films that adds value for subsequent industrial applications. This review provides an overview of the recent advances on the formation and processing technologies of whey protein-based edible films/coatings, the incorporation of additives/active ingredients for improvement, their technological properties, and potential applications in food packaging.

Whey Utilization: Sustainable Uses and Environmental Approach

The dairy industry produces large amounts of whey as a by- or co-product, which has led to considerable environmental problems due to its high organic matter content. Over the past decades, possibilities of more environmentally and economically efficient whey utilisation have been studied, primarily to convert unwanted end products into a valuable raw material. Sustainable whey management is mostly oriented to biotechnological and food applications for the development of value-added products such as whey powders, whey proteins, functional food and beverages, edible films and coatings, lactic acid and other biochemicals, bioplastic, biofuels and similar valuable bioproducts. This paper provides an overview of the sustainable utilization of whey and its constituents, considering new refining approaches and integrated processes to convert whey, or lactose and whey proteins to high value-added whey-based products.

Edible Films and Coatings Formulated with Arrowroot Starch as a Non-Conventional Starch Source for Plums Packaging

Increasing environmental awareness has promoted an interest in alternative strategies to common plastics obtained from fossil sources, stimulating research on the use of biodegradable and edible films/coatings obtained from renewable sources such as arrowroot starch. This research work aimed to evaluate the use of arrowroot starch on the formation of edible films and coatings. Increasing the concentration of arrowroot starch (from 1% to 5%, mass/mass) in the film produced by casting resulted in increased water vapor permeability (from 2.20 to 3.68 g mm/m2 day kPa), moisture content (3.22% to 7.95%), increased thickness (from 0.029 to 0.101 mm), and decreased solubility in water (from 22.45% to 13.89%). The films were homogeneous, transparent and manageable, with the exception of the film with 1% starch. Film-forming solutions at concentrations of 0%, 2%, and 4% (mass/mass) of arrowroot starch were prepared and applied to plums to evaluate post-harvest behavior when stored at 25 and 5 °C for 35 days. The 2% coating adhered well to the plums’ surfaces, was bright and was effective in reducing mass loss and respiratory rate, associated with storage temperature of 5 °C. The 4% coating presented an opaque and flocculated appearance.

Photocross-linkable Methacrylated Polypeptides and Polysaccharides for Casting, Injecting, and 3D Fabrication

For modern tissue engineering, we need not only develop new hydrogels but also suitable processing methods for them. Polypeptides and polysaccharides are potential candidates because they can be methacrylated, processed before photocross-linking, and yielded into hydrogels with given shape and form. In this study, we successfully methacrylated collagen, gelatin, hyaluronan, and alginate to 30 and 60% degree of modification. We studied methacrylated compositions (i.e., precursors) to investigate their processability. The precursors of collagen and gelatin with 60% methacrylation exhibited suitable yield stress, shear-thinning properties, and fiber-forming capability for injecting and 3D bioprinting. On the contrary, the 30% methacrylated precursors had properties suitable for casting purposes. Our study also showed that the mechanical properties of hydrogels corresponded to the used photocross-linking conditions and the degree of modification. These results underline the importance of tunability of the precursors and resulting hydrogels according to the specific fabrication method and tissue engineering application.

Development and evaluation of edible films based on cassava starch, whey protein, and bees wax

Films and edible coatings based on biopolymers have been developed as a packaging, which can be obtained from biodegradable materials and have properties similar to common plastics. These edible materials have many applications in the food industry, preventing mass transfer between the product and the surrounding environment. The objective of this study was to develop and evaluate the physicochemical and mechanical properties of edible films based on cassava starch (CS), whey protein (WP), and beeswax (BW). Response surface methodology has been used and the experiments were carried out based on face-centred composite design. On the other hand, three CS-based controls were formulated to evaluate the effect of the inclusion of WP and BW. The optimization of multiple responses established the optimal formulation: CS (3.17 %), WP (1.30 %), BW (0.50 %), presenting the following response variables: tensile stress (1.92 MPa), elongation (40.4 %), Young's modulus (42.1 MPa), water vapor permeability 1.79 × 10^-11 (g mm/s cm² Pa), swelling capacity (300.3 %), thickness (0.128 mm), moisture content (6.74 %), and colour: lightness (89.9), chromaticity a∗ (-1.8), chromaticity b∗ (7.7), saturation (9.9), tone (101.1°), and yellowness index (17.7). The selection and evaluation of this optimal formulation are essential because it is the material that shows the best possible mechanical and physicochemical properties using the studied components. The results, especially its good mechanical properties and low permeability to water vapour, would allow its application as a coating for fruits, vegetables, among others, effectively delaying its weight loss due to dehydration.

Sorption, diffusivity, permeability and mechanical properties of chitosan, potassium sorbate, or nisin incorporated active polymer films

The active multilayer packaging films were formed from low-density polyethylene (LDPE) and polyamide containing a 2% antimicrobial agent in one of the LDPE sides of the film (LDPE/polyamide/LDPE-2% antimicrobial agent). The antimicrobial agents used were potassium sorbate (PS-film), nisin (N-film), or chitosan (CTS-film). The effects of antimicrobial incorporation on water vapor permeability (P), diffusivity (D _eff ), and solubility (S _o and S _H ) of the active and control films (LDPE/polyamide/LDPE) were investigated. A dynamic vapor sorption analyzer (DVS) was used to estimate the sorption isotherms of the films at 25 °C. Peleg was found to be the best equation to describe sorption behaviors. The addition of PS and nisin into the film matrix resulted in a lower P than that of the control film. The D _eff values of the active films were lower than those of control films, except for the CTS-film. The high water-holding capacity of PS and nisin might limit the D _eff of the respective films. It was found that Henry's law was applicable to relate P, D _eff , and S _o and S _H values of the multilayer film [correlation coefficient (r) = 0.909-0.971]. The mechanical and thermal properties of the active films were not significantly affected by the incorporation of PS and nisin (p > 0.05). However, the impact of stress and elongation (transverse direction) on the CTS-film was lower than on other films, which indicated that chitosan improved the mechanical properties of the film.

Cheese Whey Processing: Integrated Biorefinery Concepts and Emerging Food Applications

Cheese whey constitutes one of the most polluting by-products of the food industry, due to its high organic load. Thus, in order to mitigate the environmental concerns, a large number of valorization approaches have been reported; mainly targeting the recovery of whey proteins and whey lactose from cheese whey for further exploitation as renewable resources. Most studies are predominantly focused on the separate implementation, either of whey protein or lactose, to configure processes that will formulate value-added products. Likewise, approaches for cheese whey valorization, so far, do not exploit the full potential of cheese whey, particularly with respect to food applications. Nonetheless, within the concept of integrated biorefinery design and the transition to circular economy, it is imperative to develop consolidated bioprocesses that will foster a holistic exploitation of cheese whey. Therefore, the aim of this article is to elaborate on the recent advances regarding the conversion of whey to high value-added products, focusing on food applications. Moreover, novel integrated biorefining concepts are proposed, to inaugurate the complete exploitation of cheese whey to formulate novel products with diversified end applications. Within the context of circular economy, it is envisaged that high value-added products will be reintroduced in the food supply chain, thereby enhancing sustainability and creating "zero waste" processes.

Relevance of Interactions between Starch-based Coatings and Plum Fruit Surfaces: A Physical-Chemical Analysis

In order to extend the shelf life of the fruit, improve appearance, and to keep all nutrition properties of the plum from diminishing, edible coatings comprised of wheat starch and wheat starch-whey protein isolate (in ratio 80/20) were created. Stand-alone films were produced to assess properties which helped to understand the phenomena occurring on the surface level of coated plums. The properties of coatings based on starch are similar to starch coatings containing oil because the natural epicuticular wax layer of plums merges with coating materials. Adding oil doubled the contact angle value and the dispersive component of the surface tension. The workings of adhesion and cohesion, spreading coefficient, water absorption, water content, and solubility in water of the films decreased. Similar processes were observed on the fruits' surface. In appearance, the coating process is similar to polishing the plum surface for removing crystalline wax. The color parameters of coated fruits did not significantly change. Newly formed bonds or interactions established between starch, whey proteins, water, glycerol, and oil are displayed by Fourier transform infrared (FTIR) analysis. This work revealed how the interactions between the epicuticular wax on the fruit's surface and the hydrocolloid-based coatings affect the efficiency of the coatings.

Role of polysaccharide conjugation in physicochemical and emulsifying properties of egg phosvitin and the calcium binding capacity of its phosphopeptides

Glycosylation with pectin simultaneously improved the emulsifying properties of egg phosvitin and the calcium binding capacity of its phosphopeptides.

Mechanical and moisture barrier properties of corn distarch phosphate film influenced by modified microcry stalline corn straw cellulose

BACKGROUND

In this paper, a novel modified microcrystalline corn straw cellulose (MMCSC) was prepared by ultrasonic/microwave-assisted treatment. Effective incorporation of MMCSC into corn distarch phosphate (CDP)-based composite films was investigated.

RESULTS

As the proportion of MMCSC was increased, tensile strength increased initially before decreasing, and the elongation at break always decreased. The composite film of MMCSC20 showed the lowest water vapor permeability (2.917 × 10^-7 g m^-1 h^-1 Pa^-1 ). The measurement of surface color showed that by the increasing of the MMCSC proportion in composite films, the L^* and b^* values and the total color difference (ΔE^* ) increased, while a^* values decreased. Fourier transform infrared spectroscopy and X-ray diffraction analysis indicated that, with the incorporation of MMCSC, the stable structure of the films was enhanced through cross-linking and the crystallinity was increased. A scanning electron microscopy study revealed the surface microstructure of films (MMCSC0-MMCSC30) was smooth and homogeneous, and there was no distinct separation in the matrix of composite films.

CONCLUSION

The incorporation of suitable MMCSC could improve the properties of composite films. The CDP-MMCSC films, which are completely biodegradable and environmental friendly, have a high potential to be used for food packaging. © 2018 Society of Chemical Industry.

How Glycerol and Water Contents Affect the Structural and Functional Properties of Starch-Based Edible Films

As starch is an inexpensive, filmogenic, easily processable and a widely available material, it is a material that can be utilized in the creation of biodegradable films and containers, presenting as a viable alternative to polymers derived from petrol. Moreover, starch could also be used to create edible coatings for fresh foods in order to extend shelf life. As such, wheat starch films with two glycerol contents were formulated to mimic the effects of compounds currently used to coat fruit. Their structural and functional properties were characterized. This study found that the transfer properties of starch films containing 33% of plasticizer was less effective than film comprised of 50% glycerol. Water diffusivity, oxygen permeability, and water vapor permeability at two different humidity gradients, surface tension, works of surface adhesion and cohesion, and moisture sorption were tested. Glycerol content does not play a significant role on the color or mechanical properties. This work shows that glycerol can strongly affect the functional properties of starch-based coatings and films.

Extraction and characterization of arrowroot (Maranta arundinaceae L.) starch and its application in edible films

This research work aimed extraction and characterization of arrowroot starch. Besides, the effects of different concentrations of starch (2.59-5.41%, mass/mass) and concentrations of glycerol (9.95-24.08%, mass versus starch mass) on films properties were evaluated by a rotational central composite 2² experimental design. Arrowroot starch showed high amylose content (35%). Low values were found for the swelling power and solubility index. The X-ray diffraction showed "C" type crystalline structures, while thermogram showed Tg around of 118 and 120 °C. The thermogravimetric analysis showed that 40% of mass loss of starch occurred between 330 and 410 °C. The films were homogeneous, transparent and manageable. Starch and glycerol concentrations played a significant role in thickness and solubility in water of films, but was not significant for water vapor permeability and tensile strength. Therefore, arrowroot is a very promising starch source for application in films.

Improvement in Functional Properties of Soy Protein Isolate-Based Film by Cellulose Nanocrystal⁻Graphene Artificial Nacre Nanocomposite

A facile, inexpensive, and green approach for the production of stable graphene dispersion was proposed in this study. We fabricated soy protein isolate (SPI)-based nanocomposite films with the combination of 2D negative charged graphene and 1D positive charged polyethyleneimine (PEI)-modified cellulose nanocrystals (CNC) via a layer-by-layer assembly method. The morphologies and surface charges of graphene sheets and CNC segments were characterized by atomic force microscopy and Zeta potential measurements. The hydrogen bonds and multiple interface interactions between the filler and SPI matrix were analyzed by Attenuated Total Reflectance⁻Fourier Transform Infrared spectra and X-ray diffraction patterns. Scanning electron microscopy demonstrated the cross-linked and laminated structures in the fracture surface of the films. In comparison with the unmodified SPI film, the tensile strength and surface contact angles of the SPI/graphene/PEI-CNC film were significantly improved, by 99.73% and 37.13% respectively. The UV⁻visible light barrier ability, water resistance, and thermal stability were also obviously enhanced. With these improved functional properties, this novel bio-nanocomposite film showed considerable potential for application for food packaging materials.

Effect of starch type on the physico-chemical properties of edible films

Food preservation is mostly related to packaging in oil-based plastics, inducing environmental problems, but this drawback could be limited by using edible/biodegradable films and coatings. Physical and chemical properties were assessed and reflect the role of the starch type (wheat, corn or potato) and thus that of the amylose/amylopectin ratio, which influences thickness, colour, moisture, wettability, thermal, surface and mechanical properties. Higher amylose content in films induces higher moisture sensitivity, and thus affects the mechanical and barrier properties. Films made from potato starch constitute a greater barrier for oxygen and water vapour though they have weaker mechanical properties than wheat and corn starch films. Starch species with higher amylose content have lower wettability properties, and better mechanical resistance, which strongly depends on the water content due to the hydrophilic nature of starch films, so they could be used for products with higher water activity, such as cheese, fruits and vegetables. It especially concerns wheat starch systems, and the contact angle indicates less hydrophilic surfaces (above 90°) than those of corn and potato starch films (below 90°). The starch origin influences optical properties and thickness: with more amylose, films are opalescent and thicker; with less, they are transparent and thinner.

Characterization of casein and casein-silver conjugated nanoparticle containing multifunctional (pectin-sodium alginate/casein) bilayer film

Casein nano particles and casein-silver conjugated nano composite containing edible bilayer pouch was developed from a heat sealable casein layer laminated with sodium alginate-pectin layer. The physicochemical, mechanical, biodegradability and the toxicity of the film were evaluated. The synthesized casein nano particle was incorporated in the casein layer (inner layer) of the film, however, the casein-silver conjugated nano composite were incorporated in the sodium alginate-pectin (outer) layer of the film. The mechanical, barrier, physical and antimicrobial properties of the film were investigated. Addition of nano composite/nano particle reduced the water solubility (from 67 to 46 % at 80 °C temperature) of the film improved the water barrier properties, light barrier properties, tensile strength and thermal properties of the film. The light barrier properties of the film increased and transparency reduced with increase in silver content in the conjugated nano composite film. The nano particles/nano composite containing film showed antibacterial activity against E. coli. The films were recorded safe for red blood cells as % haemolysis for all the tested samples were found to be well below the safe level.