Whey Protein Coatings Research Articles

A Review of Recent Developments in Edible Films and Coatings-Focus on Whey-Based Materials.

Packaging for food products is particularly important to preserve product quality and shelf life. The most used materials for food packaging are plastic, glass, metal, and paper. Plastic films produced based on petroleum are widely used for packaging because they have good mechanical properties and help preserve the characteristics of food. However, environmental concerns are leading the trend towards biopolymers. Films and coatings based on biopolymers have been extensively studied in recent years, as they cause less impact on the environment, can be obtained from renewable sources or by-products, are relatively abundant, have a good coating and film-forming capacity, are biodegradable and have nutritional properties that can be beneficial to human health. Whey protein-based films have demonstrated good mechanical resistance and a good barrier to gases when at low relative humidity levels, in addition to demonstrating an excellent barrier to aromatic compounds and especially oils. The use of whey proteins for films or coatings has been extensively studied, as these proteins are edible, have high nutritional value, and are biodegradable. Thus, the main objective of this document was to review new methodologies to improve the physicochemical properties of whey protein films and coatings. Importance will also be given to the combinations of whey proteins with other polymers and the development of new techniques that allow the manipulation of structures at a molecular level. The controlled release and mass transfer of new biomaterials and the improvement of the design of films and packaging materials with the desired functional properties can increase the quality of the films and, consequently, broaden their applications.

The Study of Combination of Biodegradable Packaging and Biocoating with Lactic Acid Bacteria as a Green Alternative for Traditional Packaging in Gouda Cheese

Biodegradable packaging, both alone and in combination with acid whey protein coatings, has been used to pack fresh Gouda cheese to improve preservation prior ripening or storage. This study involved three key components: (i) the selection of biodegradable packaging (BP), (ii) the development of a plain liquid acid whey protein concentrate, pectin-based edible coating (BP + Ch + Coating), and (iii) the incorporation of at least 6 log10 CFU (colony forming units) mL−1 Lacticaseibacillus paracasei (BP + Ch + Coating + Lp) and Lactobacillus helveticus (BP + Ch + Coating + Lh) strains. The created compositions were compared with cheese packed in conventional polyethylene (PE) packaging to evaluate their overall synergy effect in reducing microbiological spoilage and influencing chemical parameters in Gouda cheese during 45 days of ripening and cold storage. The evaluation included microbiological analysis (total LAB, Enterobacteriaceae spp., and fungi CFU) and quality assessment of pH, moisture content, water activity, texture, and colour (CEI system) during ripening and shelf life. Although biodegradable packaging (BP) alone did not protect the cheese effectively compared to conventional packaging (EVA/PE/EPC/PVDC), the combination of biodegradable packaging with a coating (BP + Ch + Coating) showed protective properties against Enterobacteriaceae spp. and mould, maintaining moisture, pH, and colour during ripening and storage. Incorporation of L. helveticus (BP + Ch + Coating + Lh) into the coating efficiently decreased the growth of fungi.

Whey Protein Isolate-Based Edible Coatings Incorporated with Jojoba Oil as a Novel Approach for Improving the Quality of Fresh-Cut Root Parsley during Refrigerated Storage

In this paper, the effect of whey-protein-isolate-based edible coatings with the addition of jojoba oil at concentrations of 1 and 2% on the qualitative characteristics of fresh-cut root parsley was evaluated. Changes in hardness, color parameters, and the contents of polyphenols and flavonoids over 28 days of refrigerated storage, as well as changes in structure, were examined. It was observed that fresh-cut parsley, uncoated and coated with a protein solution, was characterized by a decrease in hardness, from 59.32 and 59.88 to 50.98 and 48.33 N, respectively, while parsley coated with whey protein isolate with the addition of jojoba oil showed an increase in hardness during storage, from 56.28 to 66.23 N and from 52.17 to 60.49 for 1% and 2% of jojoba-oil-containing formulations, respectively. The L*, a*, and b* color parameters and hue angle mostly remained at similar levels, which indicate the maintenance of the desired color, but changes in the values were observed during storage. Parameter L* was between 79.56 and 85.33 in the control samples and between 72.54 and 84.19 in the coated samples. It was shown that the use of whey protein coatings and storage time had a positive impact on the contents of polyphenols and flavonoids in the fresh-cut parsley. The highest changes in polyphenols, from 3.13 to 9.82 mg GAE/g d.m., were observed for the samples coated with the formulation containing 1% of jojoba oil. The highest increase in flavonoid content, from 23.65 to 40.60 mg QE/g d.m., was observed for the samples coated with the film-forming solution with 2% of jojoba oil. Scanning electron microscopy showed a smaller number of pores in the vegetable tissue as a result of the coatings, and this was the most noticeable for the samples without the jojoba oil. Storage deteriorated the quality of the fresh-cut parsley surface, and the drying effect was visible. The use of protein coatings incorporated with jojoba oil modifies the quality characteristics of fresh-cut parsley, and this can find application in reducing the waste of minimally processed vegetables during storage.

Effects of Whey Protein Coating Incorporated with Propolis-β-Cyclodextrin Emulsion on Quality of Refrigerated Sea Bass Fillets (Dicentrarchus labrax)

ABSTRACT The effect of edible coating combining whey protein isolate (WPI) with Propolis/β-cyclodextrin (βCD) emulsion on quality of sea bass (Dicentrarchus labrax) fillets during 16 days of cold storage at 4°C was investigated. coatings reduced pH value and weight loss. The TVB-N and TBA values of WPI-βCD-Propolis coated samples were significantly (p < .05) lower than those of control and WPI-βCD coated samples. WPI-βCD-Propolis coatings were very effective in inhibiting bacterial growth and they prolonged the shelf life of sea bass fillets by 8 days. The color, odor, and texture scores of the WPI-βCD-Propolis treated samples were significantly higher than that of control samples and WPI-βCD samples (p < .05).

Antibacterial Properties of Whey Protein Coating and Mentha aquatica L. Essential Oil on Coliform Bacteria in Iranian White Cheese

Antibacterial Properties of Whey Protein Coating and Mentha aquatica L. Essential Oil on Coliform Bacteria in Iranian White Cheese

Effects of tea polyphenols on physicochemical and antioxidative properties of whey protein coating.

Effects of tea polyphenols (TP) incorporation on physicochemical and antioxidative properties of whey protein isolate (WPI) coating were studied. Two WPI coating solutions were prepared by heating WPI solutions (pH 8, 90°C) for 30min and then TP was incorporated. TP addition could increase the negative zeta potential of 5% solution. The surface hydrophobicity index of both solutions was increased and intrinsic fluorescence intensity decreased greatly after addition of TP. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis (2 ethylbenzothiazoline-6-sulfonate) (ABTS) radical scavenging capacities of both solutions increased with increasing TP. Compared with apple pieces coated with whey protein only, those with TP containing whey protein coatings showed lower browning index and slight changes in weight loss during 24h storage. Data indicated that TP could influence the physicochemical properties and improve the antioxidant activity of WPI coating solutions and can be used to retard the enzymatic browning of fruit during storage.

Investigation of Biodegradable Films Produced from Three Different Protein Sources for White Cheese Packaging

Biodegradable films and coatings; attract an increasing interest recently being natural and environmentally friendly alternatives to synthetic food packaging materials. Some terms such as "renewable, food preservative, thin layers, food life extender" might be used for defining these materials. Proteins have a high potential to be used in food packaging. This study aimed to compare the performances of three different protein sources (whey protein, soy protein and gluten) as biodegradable coatings for cheese samples. Effect of red grape juice addition into coating solutions was also investigated. In this study, 15 g coating solution is used to coat 3-3.5 g cheese slice in each treatment. The results of the study revealed that the coatings produced were elastic, adhesive, transparent and durable. Among the different coatings, gluten had a more stretch and adhesive structure. Soy protein and whey protein coatings inhibited the moisture loss in cheese samples slightly more than gluten films. Grape juice addition to soy and whey protein coatings made the cheese samples more resistant to microbial growth. The whey protein coating was the thickest among them. The results depicted that, whey protein coating with grape juice is the most promising application, by providing lower microbiological load and moisture loss in cheese samples, and depicting lower color and moderate solubility. In future studies, combined usage of fruit sources with protein coatings might be helpful to improve the cheese quality in biodegradable packages.

Improvement of Food Packaging-Related Properties of Whey Protein Isolate-Based Nanocomposite Films and Coatings by Addition of Montmorillonite Nanoplatelets

In the present study the effects of the addition of montmorillonite (MMT) nanoplatelets on whey protein isolate (WPI)-based nanocomposite films and coatings were investigated. The main objective was the development of WPI-based MMT-nanocomposites with enhanced barrier and mechanical properties. WPI-based nanocomposite cast-films and coatings were prepared by dispersing 0 % (reference sample), 3 %, 6 %, 9 % (w/w protein) MMT, or, depending on the protein concentration, also 12 % and 15 % (w/w protein) MMT into native WPI-based dispersions, followed by subsequent denaturation during the drying and curing process. The natural MMT nanofillers could be randomly dispersed into film-forming WPI-based nanodispersions, displaying good compatibility with the hydrophilic biopolymer matrix. As a result, by addition of 15 % (w/w protein) MMT into 10 % (w/w dispersion) WPI-based cast-films or coatings, the oxygen permeability (OP) was reduced by 91 % for glycerol-plasticized and 84 % for sorbitol-plasticized coatings, water vapor transmission rate (WVTR) was reduced by 58 % for sorbitol-plasticized cast-films. Due to the addition of MMT- nanofillers the Young’s modulus and tensile strength improved by 315 % and 129 %, respectively, whereas elongation at break declined by 77 % for glycerol-plasticized cast-films. In addition, comparison of plasticizer type revealed that sorbitol-plasticized cast-films were generally stiffer and stronger, but less flexible compared glycerol-plasticized cast-films. Viscosity measurements demonstrated good processability and suitability for up-scaled industrial processes of native WPI-based nanocomposite dispersions, even at high nanofiller-loadings. These results suggest that the addition of natural MMT- nanofillers into native WPI-based matrices to form nanocomposite films and coatings holds great potential to replace well-established, fossil-based packaging materials for at least certain applications such as oxygen barriers as part of multilayer flexible packaging films.

Effect of Sodium Sulfite, Sodium Dodecyl Sulfate, and Urea on the Molecular Interactions and Properties of Whey Protein Isolate-Based Films.

Whey protein coatings and cast films are promising for use as food packaging materials. Ongoing research is endeavoring to reduce their permeability. The intention of this study was to evaluate the effect of the reactive additives sodium sulfite, sodium dodecyl sulfate (SDS), and urea on the oxygen barrier, water vapor barrier, and protein solubility of whey protein cast films. The concentration of the reactive additives was 1 to 20 wt.-%. Dried whey protein cast films were used as substrate materials. The water vapor transmission rate, the oxygen permeability, and the protein solubility were measured. Effective diffusion coefficients and effective sorption coefficients were calculated from the results of the water vapor sorption experiments. The presence of sodium sulfite resulted in an increased number of hydrophobic interactions and hydrogen bonds and a slightly decreased number of disulfide bonds. The oxygen permeability decreased from 68 to 46 cm3 (STP/standard temperature and pressure) 100 μm (m2 d bar)−1 for 1 wt.-% SDS in the whey protein cast film. The water vapor transmission rate decreased from 165 to 44 g 100 μm (m2 d)−1 measured at 50 to 0% r. h. for 20 wt.-% SDS in the whey protein cast film. The reduction in the water vapor transmission rate correlated with the lower effective diffusion coefficient.

Modified whey protein coatings for improved gas barrier properties of biodegradable films

As a result of environmental concern, there is an increasing interest in the development of biodegradable polymers for packaging with suitable properties, as an alternative to the synthetic petroleum-based polymers. However, such biodegradable polymers are prevented for use in wide industrial and commercial packaging because of their limited gas and vapor barrier properties. This obstacle urges innovative strategies to achieve enhanced gas barrier properties using “bio-layering” technologies. Whey protein isolate (WPI), a by-product of the cheese industry, has quite promising properties for packaging purposes. It possesses good oxygen, aroma, and oil barrier properties; however, its permeability to water vapor is high. In this study, several WPI coatings were obtained, adding polyvinyl alcohol and pectin to improve the coated film properties; in addition, nanoclays were used to improve water vapor barrier properties. Comparison of neat poly (lactic acid) film versus poly (lactic acid) coated with WPI presented advantage of the later: improvement of about 90% in the oxygen barrier properties and about 27% in the water vapor barrier properties. Copyright © 2016 John Wiley & Sons, Ltd.

Storage time-dependent alteration of molecular interaction–property relationships of whey protein isolate-based films and coatings

Whey protein is a particularly well-studied and promising raw material to enhance functionality of packaging materials. However, in recent studies it was observed that several properties of whey protein isolate-based film change within the first weeks after film production. This indicates that certain intrinsic material changes take place during storage time. The overall aim of this study was to explore a time-dependent structure–property relationship of WPI-based coatings. In order to answer this question, time-dependent oxygen permeability measurements, and in addition solubility studies with different defined buffer systems combined with a Bradford assay were performed to determine intermolecular interactions in the film. The measurements clearly showed that oxygen permeability decreased by up to 85 % within 2–3 weeks after film production. The solubility tests confirmed that this decrease in oxygen permeability was accompanied and thus caused by different changes in covalent and non-covalent bonds between the polypeptide chains during storage. Based on the results of the solubility measurements it can be assumed that the cross-linking by disulphide bonds as well as hydrogen bonds is the predominant interaction formed during the first days of storage leading to a fast decrease in oxygen permeability while the importance of hydrogen bonds in relation to disulphide bonds increases during storage time leading to a further—but slower—decrease in oxygen permeability.

Effects of different coatings on preserving fruit quality of sweet cherries grown in Skardu valley of Gilgit-Baltistan during storage

This study was carried out to judge the effect of carbohydrate (chitosan, alginate and starch) and protein based (soya and whey) edible coatings on shelf life of cherries. During the study cherries were coated with 1, 2 and 3% of chitosan, alginate, starch, soya and whey protein coatings and the coated cherries were stored at room temperature up to 12 day and examined for different quality indices at interval of three days. All coatings extended keeping quality of cherries except starch. However, 3% chitosan showed best result with significant preservation of all quality parameters.

Thermal stability and flame resistance of cotton fabrics treated with whey proteins

It is well described in the literature that whey proteins are able to form coatings, which exhibit high mechanical and oxygen barrier properties, notwithstanding a great water vapour adsorption. These peculiarities have been exploited for applying a novel protein-based finishing treatment to cotton and for assessing the protein effect on the thermal and thermo-oxidative stability and on the flame retardant properties of the cellulosic fabric. Indeed, the deposited whey protein coatings have turned out to significantly affect the thermal degradation of cotton in inert and oxidative atmosphere, and to somehow modify its combustion when a flame has been applied. Furthermore, the influence of the secondary and tertiary structure of these proteins on the morphology of the deposited coating, and thus on the thermal and flame retardant properties of the treated fabrics, has been evaluated by performing a denaturation thermal treatment before the protein application.

Effects of edible coatings based on ultrasound-treated whey proteins in quality attributes of frozen Atlantic salmon (Salmo salar)

Abstract The effects of ultrasound-treated whey protein coatings on frozen Atlantic salmon quality parameters were evaluated. The experiment was performed using an ultrasonic bath at a frequency of 35 kHz and three sonication times (1, 15 and 60 min). The yield, the thaw yield, the drip loss in thawing, the drip loss after chilled storage and the cooking loss of fish samples were not influenced by the ultrasound treatment of coatings when compared to fish samples with untreated whey protein coatings. Decreases in yield, drip loss in thawing and drip loss after chilled storage were observed in samples from whey proteins sonicated 60 min in relation to those sonicated 15 min. The ultrasound treatment of whey proteins did not modify the colour of frozen and thawed fillets but increased L* and whiteness of cooked samples in comparison with untreated whey protein coated samples. All whey protein coatings decreased the lipid oxidation of fish fillets. However, the ultrasound treatment of coatings significantly delayed the lipid oxidation of salmon pieces in comparison with those coated with untreated proteins. The sensory properties of salmon samples were not negatively affected by these coatings. Industrial relevance Freezing is a very usual method of fish preservation; some changes during frozen storage that decrease product quality can occur, such as lipid oxidation. The results obtained in this investigation show that ultrasound applied to whey protein coatings could be useful for the reduction of the lipid oxidation of frozen salmon. These treated coatings could be a good alternative to conventional packaging and, at least, they could partially substitute plastic packaging. The edible coatings can contribute to reduce the plastic packaging residues of frozen seafood industry and the environmental contamination.

Whey Protein Films and Coatings: A Review

Whey is a by-product of the cheese-making industry. The most important constituent of whey is Whey Protein (WP) generally used in infant formulas and sports food. Nowadays, great efforts are being made to find out new WPs applications, e.g. production of edible films. Edible or biodegradable films constitute a convenient means to prolong the shelf life of foods and increase their quality without contributing to environmental pollution. Apart from acting as selective barriers for moisture and gas migration, these films may operate as carriers of many functional ingredients. Such ingredients may include antioxidants, antimicrobial agents, flavors, spices and colorants which improve the functionality of the packaging materials by adding novel or extra functions. In this article, the functional properties of edible films made with WPs and their applications in food industry will be reviewed.

Application of whey proteins as coating ingredients

Technologies are described where activated whey proteins are used for encapsulating sensitive food materials. The mechanism, governing the solubility of whey protein films and coatings, on which these technologies are based was investigated.

Effect of Whey Protein Coating on Quality Attributes of Low‐Fat, Aerobically Packaged Sausage during Refrigerated Storage

Whey protein-based edible coating was used to reduce oxidative degradation and microbial growth of low-fat sausages (LFSs) stored at 4 degrees C for 8 wk, under aerobic package. Whey protein coating reduced (P<0.05) thiobarbituric acid-reactive substances (TBARS) and peroxide value (PV) formation compared to control sausages. The percent inhibition of TBARS and PV for whey protein-coated sausages, compared to the control, was 31.3% and 27.1%, respectively. The ability of the whey protein coating to provide a moisture barrier for the sausages was reduced (P<0.05). In addition, a reduction of moisture loss by 36.7% compared to the control was achieved by whey coating. However, whey protein coating of LFSs did not inhibit the growth of either the total number of aerobic bacteria or of Listeria monocytogenes. These results indicated that whey protein coating had an antioxidative activity in LFSs under aerobic package during refrigerated storage.

Dynamic rearrangement of disulfide bridges influences solubility of whey protein coatings

In this study, the mechanism governing the solubility of whey protein films and coatings was investigated. The building blocks for these films and coatings were aggregated whey proteins. Solubility was related to the continuity of the network of disulfide cross links between the building blocks and the dynamics of rearrangements of disulfide bonds occurring via the so-called thiol–disulfide exchange reaction. By controlling either the accessibility of thiol groups or the accessibility of disulfide bonds within the whey protein aggregates, solubility of whey protein coatings and films could be tuned. These new insights will help improving the properties of protein coating, promoting the applicability of whey proteins in films, encapsulates and coatings.

Physical Properties of Whey Protein Coating Solutions and Films Containing Antioxidants

Antioxidants (ascorbyl palmitate and alpha-tocopherol) were incorporated into 10% (w/w) whey protein isolate (WPI) coating solution containing 6.67% (w/w) glycerol (WPI:glycerol = 6:4). Before incorporation, the antioxidants were mixed using either powder blending (Process 1) or ethanol solvent-mixing (Process 2). After the antioxidant mixtures were incorporated into heat-denatured WPI solution, viscosity and turbidity of the WPI solutions were determined. The WPI solutions were dried on a flat surface to produce WPI films. The WPI films were examined to determine transparency and oxygen-barrier properties (permeability, diffusivity, and solubility). WPI solution containing antioxidants produced by Process 1 and Process 2 did not show any difference in viscosity and turbidity, but viscosity was greater for the WPI solution with rather than without antioxidants. WPI films produced by Process 2 were more transparent than the films produced by Process 1. Oxygen permeability of Process 1 film was lower than Process 2 film. However, both the diffusivity and solubility of oxygen were statistically the same in Process 1 and Process 2 films. Both control WPI films and antioxidant-containing WPI films had very low oxygen solubility, comparable to polyethylene terephthalate films. Permeability of antioxidant-incorporated films was not enhanced compared to control WPI films.

Recobrimento de laranja 'Pêra' com filme de concentrado protéico de soro de leite associado a plastificantes

O objetivo desse estudo foi avaliar o efeito de coberturas à base de concentrado protéico de soro de leite (CPSL), associadas a dois tipos de plastificantes (glicerol e sorbitol), em laranja 'Pêra'. As frutas foram lavadas e higienizadas de acordo com os padrões comerciais e submetidas à aplicação das coberturas. As coberturas à base de CPSL não foram eficientes na redução da perda de massa fresca da laranja 'Pera', independentemente do plastificante utilizado. Depois de 11 dias de armazenagem, as laranjas cobertas com solução filmogênica de 6% de proteína e 6% de glicerol, e laranjas cobertas com solução de 4% de proteína e 8% de sorbitol perderam menos massa, quando comparadas às outras combinações de proteína e plastificante. As coberturas não interferiram nas características físico-químicas das laranjas.