High pressure homogenization of mechanically deboned chicken meat protein suspensions to improve mechanical and barrier properties of edible films

Effects of High-Pressure Homogenization Treatment on the Development of Antioxidant Zanthoxylum bungeanum Leaf Powder Films for Preservation of Fresh-Cut Apple

This study determined that Zanthoxylum bungeanum leaves (ZBLs) are rich in functional components such as cellulose, protein, flavone, and polyphenols. Therefore, they were used as the main raw material, with sodium alginate as a thickener and glycerol as a plasticizer, to investigate the preparation of active films from ZBL powder through high-pressure homogenization (HPH). The physical, optical, mechanical, and antioxidant properties of the films were evaluated, and their application in preserving fresh-cut apples was examined. The results showed that the optimal concentration of ZBL powder was 1.5% under a 30 MPa HPH treatment. The resulting HPH-treated films exhibited a denser microstructure and improved water vapor barrier properties and mechanical strength. Compared to the films without HPH treatment, the tensile strength increased from 4.61 MPa to 12.13 MPa, the elongation at break increased from 21.25% to 42.86%, the water vapor permeability decreased from 9.9 × 10-9 g/m·s·Pa to 8.0 × 10-9 g/m·s·Pa, and the transparency increased from 25.36% to 38.5%. Compared to the control group, the fresh-cut apples packaged with the HPH-treated ZBL active films exhibited effective preservation of apple quality during a five-day period at 4 °C and 70% humidity, showing better preservation effects than the other groups. In conclusion, the use of HPH treatment in developing novel biopolymer active films from ZBL powders with enhanced properties holds potential for various applications.

Non-thermal techniques as an approach to modify the structure of milk proteins and improve their functionalities: a review of novel preparation

BACKGROUND

Milk proteins (MPs) have been widely used in the food industry due to their excellent functionalities. However, MPs are thermal-unstable substances and their functional properties are easily affected by heat treatment. Emerging non-thermal approaches (i.e., high-pressure homogenization (HPH), ultrasound (US), pulsed electric field (PEF)) have been increasingly popular. A detailed understanding of these approaches' impacts on the structure and functionalities of MPs can provide theoretical guidance for further development to accelerate their industrialization.

SCOPE AND APPROACH

This review assesses the mechanisms of HPH, US and PEF technologies on the structure and functionalities of MPs from molecular, mesoscopic and macroscopic levels, elucidates the modifications of MPs by these theologies combined with other methods, and further discusses their existing issues and the development in the food filed.

KEY FINDINGS AND CONCLUSIONS

The structure of MPs changed after HPH, US and PEF treatment, affecting their functionalities. The changes in these properties of MPs are related to treated-parameters of used-technologies, the concentration of MPs, as well as molecular properties. Additionally, these technologies combined with other methods could obtain some outstanding functional properties for MPs. If properly managed, these theologies can be tailored for manufacturing superior functional MPs for various processing fields.

Aloe barbadensis Based Bioactive Edible Film Improved Lipid Stability and Microbial Quality of the Cheese

An attempt was made to develop a bioactive edible film using carrageenan and A. vera gel for enhancing the storage quality of cheese using kalari, a popular Himalayan cheese, as a food-model system. The film was evaluated for various physicomechanical and oxidative properties (ABTS (2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonate)) and DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activities, total flavonoid and phenolic contents). Based on preliminary trials, 1% A. vera gel was found to be optimum. The addition of the gel resulted in a significant decrease in moisture content, transparency, solubility, and water-vapor transmission rate and increased the thickness and density of the film. The film showed antimicrobial properties against E. coli and significantly (p < 0.05) decreased the lipid-oxidation (thiobarbituric acid reactive substances, free-fatty acids, and peroxide values) and increased microbial-quality (total-plate, psychrophilic, and yeast/molds) of the samples during 4-week refrigerated storage (4 ± 1 °C). The film also exhibited a significant positive impact on the sensory quality of the cheese, indicating the potential for commercial applications for quality control of cheese during storage.

Pectin-based color indicator films incorporated with spray-dried Hibiscus extract microparticles

Colorimetric films incorporated with anthocyanins as an indicator for freshness monitoring have aroused growing interest recently. The pH-sensing colorimetric film were developed based on pectin (HM), containing aqueous hibiscus extract microparticles (HAE). HAE microparticles were obtained by spray drying with different wall materials (Inulin -IN, maltodextrin- MD and their combination). The films were obtained on large scale by continuous casting. These films were characterized for physicochemical analysis, morphological structure, thermal and barrier properties, antioxidant activity, and color change at different pH. The addition of HAE microparticles caused relevant changes to HM-based films, such as in mechanical behavior and improved barrier property (11-22% WVTR reduction) depending on the type of wall material used and the concentration added. It was verified with the thermal stability of films, with a slight increase being observed. The color variation of smart films was entirely pH-dependent. Overall, the proposed color indicator films showed unique features and functionalities and could be used as an alternative natural pH indicator in smart packaging systems.

Structural characteristics of pea protein isolate (PPI) modified by high-pressure homogenization and its relation to the packaging properties of PPI edible film

This study modified pea protein isolate (PPI) structure by high-pressure homogenization (HPH) and investigated PPI structural relation to the packaging properties of PPI film. HPH decreased PPI particle size, reduced surface charge, increased surface hydrophobicity, and increased free sulfhydryl, providing greater potential for covalent bonding during film formation. HPH decreased opacity of PPI films from 7.39 to 4.82 at pressure of 240 MPa with more homogeneous surface. The tensile strength and elongation at break were increased from 0.76 MPa to 1.33 MPa and from 96% to 197%, respectively, after treatment at 240 MPa. This improvement was due to the enhanced protein-protein and protein-glycerol hydrogen bonding as evidenced by FTIR. Increased β-sheet and decreased α-helix by HPH was also observed, and β-sheet was highly correlated to film tensile strength (Pearson coefficient of 0.973, P < 0.01). Principle component analysis visualized the influence of HPH treatment, and confirmed the association between structural characteristics and film properties.

Tailoring protein intrinsic charge by enzymatic deamidation for solubilizing chicken breast myofibrillar protein in water

Inspired by the salt-in effect, the potential use of protein-glutaminase (PG) to increase the intrinsic charges of chicken breast myofibrillar proteins (CMPs) for enhanced water solubility was tested. The degree of deamidation (DD) and solubility of CMPs increased with PG reaction time. Over 60% of CMPs were soluble in water under a DD of 6.5% due to specific conversion of glutamine to glutamic acid. PG deamidation could remarkably increase the net charge of CMPs with a merit in maintaining most of the amino acid and protein subunit compositions. Such a high electrostatic repulsion exerted a transformation of β-sheet into α-helix, unfolded the structure to expose hydrophobic residues, and allowed the dissociation of myofibril and release of subunits (myosin, actin or their oligomers), leading to a stable colloidal state. This work may foster the engineering advances of protein micro-modification in the tailor manufacture of muscle protein-based beverages.

Cold plasma enhanced natural edible materials for future food packaging: structure and property of polysaccharides and proteins-based films

Natural edible films have recently gained a lot of interests in future food packaging. Polysaccharides and proteins in edible materials are not toxic and widely available, which have been confirmed as sustainable and green materials used for packaging films due to their good film-forming abilities. However, polysaccharides and proteins are hydrophilic in nature, they exhibit some undesirable material properties. Cold plasma (CP), as an innovative and highly efficient technology, has been introduced to improve the performance of polysaccharides and proteins-based films. This review mainly presents the basic information of polysaccharides and proteins-based films, principles of CP modified biopolymer films, and the effects of CP on the structural changes including surface morphology, surface composition, and bulk modification, and properties including wettability, mechanical properties, barrier properties, and thermal properties of polysaccharides, proteins, and polysaccharide/protein composite-based films. It is concluded that the CP modified performances are mainly depending on the polysaccharides and proteins raw materials, CP generation types and treatment conditions. The existing difficulties and future trends are also discussed. Despite natural materials currently not fully substitute for traditional plastic materials, CP has exhibited an effective solution to shape the future of natural materials for food packaging.

Physicochemical properties of seed protein isolates extracted from pepper meal by pressure-assisted and conventional solvent defatting

Pepper seed is one by-product in pepper processing, rich in protein, fat, and fiber, and is a new plant-based protein source. In this paper, the physicochemical and functional properties of pepper seed protein isolates (PSPIs) extracted from pepper meal by pressure-assisted defatting (PAD) and conventional solvent defatting (CSD) were investigated. The yields of SPIs extracted by CSD and PAD were 22.8% and 20.5%, respectively. Compared with the PSPIs obtained by CSD, the solubility, water-holding and oil-holding capacities, and emulsifying and foaming abilities of the PSPIs obtained by PAD were significantly increased by 11.22%, 29.17%, 40%, 160%, and 100%, respectively. Additionally, UV-visible, intrinsic fluorescence and infrared spectroscopic characterization revealed the tertiary and secondary conformation changes of the PSPIs, which might contribute to the improvement of their functional properties. Overall, PAD significantly improved the functional properties of the PSPIs. The PSPIs extracted by this innovative technology would be a new plant protein alternative for food formulations with better functional properties.

Development and Characterization of Fenugreek Protein-Based Edible Film

The present investigation studied the physicochemical, mechanical, structural, thermal, and morphological attributes of a novel edible film formed from fenugreek protein concentrate. Films were produced at different pH-9, 10, 11, and 12-and the effect of the pH on the films was studied. As the pH increased, tensile strength increased while water vapor absorption decreased, which is interrelated to the surface morphological properties; as the pH increased, the surface became smoother and compact without any cavities. The films produced were darker in color. Fenugreek protein films exhibited good thermal stability. Fourier transform infrared spectroscopy (FTIR) revealed the presence of strong bonding for the films made at alkaline pH. X-ray diffraction analysis (XRD) indicated the major structure of the film was amorphous. The study demonstrated that the fenugreek protein concentrate film has influential characteristics and can be used as an edible packaging film.

Preparation of pH-indicator films based on soy protein isolate/bromothymol blue and methyl red for monitoring fresh-cut apple freshness

Intelligent pH-indicator films based on soy protein isolate (SPI) were prepared using pH-sensitive dyes (bromothymol blue and methyl red). The addition of mixed indicators imparts pH-indicator films with an appreciable microstructure, acceptable water resistance, and favorable optical properties. The incorporation of the mixed indicators did not lead to significant improvement in the mechanical properties of films due to weak ionic cross-linking by hydrogen bonding between the SPI macromolecules and low-molecular-weight indicators. Fourier-transform infrared spectroscopy indicated hydrogen bond-mediated intermolecular interactions, and scanning electron microscopy showed that BB/MR were well dispersed in the SPI film. The indicator addition hindered the sorption and passage of water molecules. The water vapor permeability, moisture sorption, moisture content, and total soluble matter were 4.32 to 6.12 ×10^-12  g·cm/cm² ·s·Pa, 36.70% to 73.33%, 25.28% to 44.11%, and 8.21% to 25.56%, respectively. Also, the addition of indicators reduced UV light transmittance with minimal effect on the transparency of the film. The presence of indicators enhanced the pH sensitivity, seen as a visible color reaction at different pHs (total color difference, ΔE > 5). When the pH-indicator film containing 8 ml/100 ml final film emulsions was used to monitor the fresh-cut apple freshness, a green color for fresh status was observed, which turned blue after 60 h. Collectively, our findings suggested that indicator-containing SPI films have the potential for monitoring the freshness of fruits. PRACTICAL APPLICATION: pH-indicator films can help consumers to identify the freshness of packaged food by a change in the color of the packaging material, which is easily visible to the unaided eye without the need for opening the packaging. This protects consumers' interests.

The Effects of Novel Thermal and Nonthermal Technologies on the Properties of Edible Food Packaging

Edible packaging is influenced by factors such as formulation, production technology, and solvent and additive properties. With the increase in the request for coating and film quality, appropriate form, and high product safety and storage period, various technologies such as high hydrostatic pressure, irradiation, ultrasound, high-pressure homogenization, cold plasma, and microwave have been reviewed. The present study states definitions and mechanisms of novel technologies. The experimental condition, packaging matrix, and the results pertaining to the effects of these technologies on various types of edible packaging is also discussed. The most of the matrix used for packaging was whey protein, soy protein isolate, chitosan, and gelatin. The technologies conditions such as power, frequency, time, temperature, dose, pressure, and voltage can have a significant influence on the application of them in film and coating. Therefore, finding the optimum point for the features of the technologies is important because improper use of them reduces the properties of the edible packaging.

Development and characterization of black mulberry (Morus nigra) pekmez (molasses) composite films based on alginate and pectin

Production of composite films is an important approach to improve functionality of edible films, by combining different polysaccharides, proteins, and lipids. Carbohydrate-based composite films are most attractive, which have good film-forming ability due to their unique colloidal properties. Fruit purees include high polysaccharide content that plays a role to have desirable film properties including mechanical resistance, efficient barrier properties, and selective permeability against oxygen transmission. The purpose of this study was to characterize physical, barrier, mechanical, thermal, and water sorption properties of composite films formulated with different mulberry pekmez concentrations (26, 32, and 38 °Brix) based on alginate or pectin. All film-forming solutions were showed shear thinning behavior with higher yield stress and viscosity-shear rate data were fitted to Ostwald de Waele model (R²  ≥ 0.943). A noticeable decrease in tensile strength of films with increasing concentration was determined, but films prepared with high concentration showed more flexible. The mechanical properties of pectin films exhibited weakened properties compared to alginate films. Increasing pekmez concentration in the film matrix improved the water vapor permeability of alginate films, whereas pectin films showed reverse behavior as resulting in cracks and crack propagation within the structure. The sorption isotherms of films showed a typical profile of foods contain high soluble components and the Guggenheim-Anderson-deBoer (GAB) model gave a good fit for all of the obtained data. The results showed that mulberry pekmez films based alginate have a potential for food applications depends on the physical properties and for the replacement of non-biodegradable plastic packaging.

Development and Properties of Fish Gelatin/Oxidized Starch Double Network Film Catalyzed by Thermal Treatment and Schiff' Base Reaction

In order to improve the properties of fish gelatin (FG), oxidized starch (OS) was adopted to form hetero-covalent linkage with it based on thermal treatment and the Schiff’ base reaction. The effects of different ratios of FG/OS (ranging from 10:1 to 2:1) on the properties of films were investigated. OS improved the mechanical and barrier properties of films significantly, while the moisture content decreased as OS concentration increased. The optimum concentration was obtained at the loading amount of 1.5% (w/v) OS. FT-IR spectra revealed the covalent cross-linking between FG and OS induced by Schiff’ base reaction. Moreover, composite films had superior preservation effect on blueberry, according to the results of weight loss, total soluble solids, titratable acidity, and total anthocyanin content. Therefore, this study suggested that FG-OS double network films (FODF) has great potential in the packaging industry.