Improvement of Physicochemical Properties of Cheese Whey Edible Film through Egg White Addition

This study aims to develop and characterize cheese whey edible film with egg white addition as an environmentally friendly packaging. Whey, a byproduct of the cheese-making process, is rich in nutrients but has not been optimally utilized. This study uses a randomized block design with 4 treatments: no egg white addition (control), and the addition of 1.5%, 3%, and 4.5% egg white, each with 5 repetitions. The results show that the addition of egg white significantly increases the thickness, solubility time, water vapor transmission rate and protein content (p < 0.05) but has no significant effect on water content (p > 0.05). The thickness of the edible film ranges from 0.149 to 0.242 mm, solubility time from 53 to 109 seconds, water vapor transmission rate from 4.91 to 7.04 g/mm²/day, moisture content from 16.85% to 21.10%, protein content from 4.62% to 9.57%, and elongation from 30.55% to 36.90%. Based on research, adding B (1.5%) to egg whites produces the best treatment. This study demonstrates that the combination of whey and egg white can produce edible films with good physical and chemical characteristics, which can be used as an alternative packaging for food products, reducing plastic usage, and increasing the economic value of whey and egg white as waste products.


INTRODUCTION
In the cheese-making process, a liquid byproduct called whey is produced.Whey is obtained from the curd filtration process during cheese production.Despite its good nutritional content, whey has yet to be properly utilized.According to Pereira et al. (2015) whey has a fairly high lactose and protein content.Whey can be used as a raw material in the production of edible film packaging.Edible film is an alternative packaging that can be developed to reduce plastic packaging, which causes water and soil pollution due to its difficulty in decomposing by bacteria and microbes.
One of the dairy farms producing cheese in West Sumatra is Lassy Dairy Farm.Lassy Dairy Farm is located in Canduang District, Agam Regency, West Sumatra produce 15 kg of cheese daily, and the whey obtained from each process can reach 150 liters.The whey at Lassy Dairy Farm has yet to be fully utilized.According to Cinelli et al. (2014), the protein content of whey used as a raw material for edible film can enhance its oxygen barrier properties.
Whey edible film needs additional materials to enhance its mechanical and functional properties.Egg white (albumen) is an additive that can be used in edible film because it has good gel-forming properties, thus improving the film's elasticity.This is due to the ovomucin content in albumen, a glycoprotein that can form gel-like structures and further create a microscopic fibre-like consistency (Manab et al., 2017).
Egg white protein has better transparency than other proteins, such as soy protein isolate and zein protein film, with absorption and digestibility rates of up to 98% in the human body and is a good filmforming agent (Peng et al., 2017).In the research by Huang et al. (2020), making edible film from egg white protein (EWP) and carrageenan mixed in a 40:60 ratio increased elongation to 10.85%, reduced oxygen permeability, water vapor permeability (WVP), and water solubility time to 4.17 meq/kg, 1.59 g mm/m² Pa, and 29.9 seconds, respectively.In previous research referenced from Manab et al. (2017), egg white was isolated to obtain lysozyme extract.The addition of 1% lysozyme to whey edible film by coating reduced microbial levels in gouda cheese, such as lactic acid bacteria, molds/yeasts, coliforms, and enterococci.
One of the businesses that use a lot of eggs in West Sumatra is making teh talua (egg tea).In making teh talua, usually, only the egg yolk is used, while the egg white is set aside.Whey, which still contains nutrients, can be combined with egg white.Egg white (albumen), containing ovomucin, has good gel-forming properties.Additionally, the lysozyme content in egg white can act as aantibacterial agent.Lysozyme can also bind to other proteins, thus increasing the protein content of the edible film.By using egg white from the teh talua business, it is expected to increase its economic value and optimize the byproducts of teh talua, so the egg white can be utilized to the fullest.

Methods
The research method used is a randomized block design (RBD) with 4 treatments and 5 replications: A = No egg white addition (control), B = 1.5% addition, C = 3% addition, and D = 4.5% addition.

Preparation of Edible Film with Egg White Addition (Modification of Juliyarsi et al., 2020)
Egg whites which are waste are obtained directly from the talua seller at the Pasar Baru at Andalas University.Whey from cheese production and ethanol in a 1:1 ratio was prepared, amounting to 50 ml.The mixture was heated at 55°C -60°C, then 1% CMC of the total material was added.Glycerol, amounting to 3% of the total material, was added while maintaining the temperature at 55°C -60°C and stirring with a magnetic stirrer at a speed of 400 rpm.Egg white was added according to the treatment, homogenized for 30 min, and then poured into a petri dish mold with a diameter of 15 cm with a volume of 50 ml.It was placed in an oven at 60°C for 24 h, left for 18 h, and then the film was peeled off from the mold.

Measurement of Edible Film Characteristics with Egg White Addition Thickness Test (Ulum et al. 2018)
The thickness of the edible film was measured using a digital caliper (Model MDC-25M, Mitutoyo, MFG, Japan) with an accuracy of 0.01 mm.The film thickness was measured at 5 different points, and the average value was calculated as the film thickness.

Solubility Time (Coniwanti, 2014)
A sample of the edible film cut into 2 x 2 cm² was placed in water at 100°C.The time it took for the sample to dissolve completely in the water was recorded.

Water Vapor Transmission Rate (WVTR) (Sitompul et al., 2017)
A sample of the edible film cut into 5 cm² was cut and placed over a container filled with distilled water.This container was then placed inside a second container filled with silica gel that had been dried at 105°C for 5 h.After 24 h, the sample was weighed, and the water vapor transmission rate was calculated.

Moisture Content (AOAC, 2005)
Moisture content was determined using the oven method.The dish was ovendried at 110°C for 1 h, then cooled in a desiccator to remove water vapor and weighed.Five grams of the sample were weighed in the dried dish and oven-dried at 105°C for 8 h.The sample was then cooled in a desiccator for 30 min and weighed.

Protein Content (AOAC, 2005)
Protein content in edible film was measured using the Kjeldahl method, which consists of three stages consist of digestion, distillation, and titration.

Elongation (Togas, 2017)
Elongation is measured with a modified elongation test tool then the film is given a load and the elongation is calculated when the film breaks.Elongation was calculated using the formula: (B-A)/A x 100%, where A is the initial length of the edible film and B is the length of the edible film at break.

Data Analysis
The obtained data were analyzed using SPSS software, and if significant treatment effects (p < 0.05) were found, Duncan's Multiple Range Test (DMRT) was performed.

RESULT AND DISCUSSION
The research results in the form of processed cheese whey edible film through egg white addition products can be seen in Figure 1 and the results of the research values of all parameters can be seen in Table 1.

Thickness
Based on the table above, it can be seen that the thickness of whey edible films with added egg white ranged from 0.149 to 0.242 mm in the research results.Analysis of variance results indicated a significant effect (p < 0.05) of added egg white on the thickness of the edible films.Treatment A (0%) significantly differed (p < 0.05) from treatments B (1.5%), C (3%), and D (4.5%), having the lowest thickness because no egg white was added in this treatment, thus lacking additional components to increase film thickness.Meanwhile, treatments B (1.5%), C (3%), and D (4.5%) showed a significant increase in thickness due to the higher concentrations of added egg white.The increase in thickness of whey edible films with added egg white is attributed to the solid components present in egg white.Manab et al. (2017) described egg white composition as: protein (11.3%), carbohydrate (1%), fat (0.08%), water (86.6%),minerals (0.2%), water-soluble vitamins and pigments (e.g., ovoflavin) at 0.017 mg.
This diverse composition leads to a higher solid content in the solution, thus increasing the number of polymer units forming the film and affecting its thickness.This finding aligns with Ningsih (2015) assertion that an increase in solution solid content results in a higher number of polymer units forming the matrix, thereby increasing film thickness.Supported by Coniwanti et al. (2014), who also observed that the thickness of edible films increases with higher concentrations of added ingredients.
Consistent with Juliyarsi (2020) research, the addition of active ingredients to edible films leads to an increase in polymer units forming the matrix, accompanied by an increase in total dissolved solids in the edible film, thereby increasing film thickness.This research is consistent with Kafiya and Danar (2022) findings that the thickness of whey edible films with added lemongrass essential oil ranged from 0.132 to 0.212 mm.The thickness observed in their study was lower than that reported by Juliyarsi et al. (2021), where the thickness of whey edible films with added virgin coconut oil (VCO) ranged from 0.20 to 0.34 mm.Juliyarsi (2019) also reported that whey edible films with added lactic acid bacteria isolate from fermented durian had a thickness ranging from 0.134 to 0.144 mm, which was lower than the findings of this study.
The variations in these studies' findings are attributed to differences in the compositions of the materials used in their respective film formulations.Referring to the Japan Industrial Standard (JIS) Z: 1707: 2019, edible films are categorized as meeting standards if they have a thickness of 0.25 mm.Treatments A, B, and C already meet this standard, while treatment D does not yet meet the established standard.

Solubility Time
Based on the table above, it can be seen that the dissolution time of egg white whey edible films from the research ranges between 53-109 seconds.Analysis of variance shows that the addition of egg white significantly affects (p < 0.05) the dissolution time of the edible films.The dissolution time increases proportionally with the concentration of added egg white.Treatment D (4.5%) had the longest dissolution time due to the higher percentage of egg white added.The higher concentration of egg white in the edible films leads to more solid film material that needs to dissolve, thus requiring more time for dissolution.Conversely, treatments A (0%) and B (1.5%) did not differ significantly (p > 0.05) because the 1.5% concentration of egg white was not sufficient to prolong the dissolution time.Both arguments are in line with Unsa et al. (2009), the more additives and plasticizers used, the more the solubility time of edible film increases.
One of the solid components of egg white is protein.Proteins can bind and form stronger networks, resulting in increased film thickness and higher water resistance, making the film more difficult to dissolve.Higher protein concentrations produce films that are more water-resistant, stronger, and dissolve more slowly.According to McClements and Jafari (2018), egg white proteins are amphipathic (having hydrophobic and hydrophilic groups) with long chains.Hydrophilic components in egg white, such as ovalbumin (soluble in water and capable of forming good gels), and hydrophobic components like ovomucin (less soluble in water, which helps improve mechanical properties of the film), interact with each other.This is supported by Lomakina and Mikova (2006), who found that egg white proteins like ovalbumin and ovomucin interact to form stable foams and gels, where ovalbumin primarily contributes to water retention and gel formation, while ovomucin enhances structural strength and water resistance.Additionally, lipid content with strong hydrophobic properties that are not soluble in water in egg whites in small amounts can also affect dissolution time.Supported by Manab et al. (2017), egg whites contain low fat, namely 0.08%.
The results of this study are in line with the research of Juliyarsi et al. (2021), which results in the dissolution time of egg white whey edible film with the addition of VCO around 46.50-170.78seconds, but the results of the research are lower than those of Juliyarsi et al. (2020) egg white whey edible film dissolves with the addition of turmeric extract, which is obtained is 134-136 seconds.The difference in results is due to differences in the components of the materials composing the study with this study, turmeric is rich in starch which is higher in the binding of the hydroxyl group of starch which affects the dissolution time.

Water Vapor Transmission Rate
Based on the table above, it can be seen that the water vapor transmission rate of egg white whey edible films from the research results ranges from 4.91 to g/mm2/day.Analysis of variance shows that the addition of egg white significantly affects (p < 0.05) the water vapor transmission rate of the edible films.The water vapor transmission rate increases proportionally with the concentration of added egg white.Treatment D (4.5%) had a high water vapor transmission rate due to the large percentage increase in the hydrophilic properties of the albumin.This research is in line with the research of Fahrullah et al. (2023) where the water vapor transmission rate of whey gelatin edible film that he got was 4.87-6.22g/mm2 /day.The results of this study have met the standards Japan Industrial Standard (JIS) Z: 1707: 2019 edible films categorized as meeting the standard are those with a maximum water vapor transmission rate of 7 g/m 2 /day.
Egg whites have hydrophilic properties that are spherical in shape and are easily bonded to water so that they can increase the water vapor transmission rate.
The protein in egg white has polar groups that are easily soluble in water such as ovalbumin, ovotransferrin, and lysosomes.This is supported by Huang et al. (2022) proteins that are present in egg white will be bonded to water through the interaction of amino acid groups and are in such as -OH, -NH2, and -COOH will then form hydrogen bonds with water molecules so that the protein is soluble in.Setyaningrum et al. (2017) revealed that the hydrophilic properties contained in the base material of the film will increase the water vapor transmission rate.

Water Content
Based on the table above, it can be seen that the water content of edible films made from whey and egg white ranges from 16.85% to 21.10% as found in the research.The results of the analysis of variance showed that the addition of egg white had no significant effect (p > 0.05) on the moisture content of the edible film.The results were not significantly different because the addition of egg white up to 4.5% was not enough to significantly increase the moisture content of edible film.The moisture content of edible film can be influenced by the water content of the film constituent material.According to Salimah et al. (2016) the basic ingredients and additives used in filmmaking will affect the moisture content.
The water content of whey used in the study was 94% and the water content of egg white was 86.0%.The water content in egg white and whey will contribute to the water content of the edible film produced.This is in line with the opinion of Nursiwi et al. (2015) that cheese whey has a high water content of 93.42%.Egg white is also mostly composed of water, which is 86.6% water (Manab, 2017).The water content obtained in this research, is higher compared to Kammani (2014) andFahrullah et al. (2023) who studied whey edible films using carrageenan as a base material and different types of plasticizers, obtaining water content values of 16.43% and 12.55-15.28%,respectively.This research is consistent with Rusli et al. (2017) where carrageenan edible films with glycerol had water content ranging from 17.14% to 20.86%.However, the water content in this research is lower compared to Pratama (2016) and Juliyarsi et al. (2023) who studied whey edible films with added green betel leaf and roselle extract, obtaining water contents of 23.06% and 22.98%, respectively.Differences in water content are due to variations in additional components used in enhancing the edible films compared to previous studies.
Another factor influencing water content is glycerol.Glycerol, being amphipathic (having both hydrophobic and hydrophilic groups), easily binds with water components, contributing to the water content of the edible films.This aligns with Rusli et al. (2017) who stated that glycerol, a simple glyceride compound with hydrophilic and hygroscopic properties, freely binds with water components and its water-retaining properties contribute to the water content of the resulting edible films.The water content of edible films is crucial in maintaining product stability.Low water content in edible films is desired to avoid shortening the shelf life of products, as edible films can transfer moisture to the packaged products.This is consistent with Nursiwi et al. (2015) who suggested that when using edible films as primary packaging, water content should not be added to the products to avoid reducing their shelf life and causing product damage.

Protein Content
Based on the table above, the protein content of whey and egg white edible films in the study ranged from 4.62% to 9.58%.Analysis of variance showed that the addition of egg white significantly affected (p < 0.05) the protein content of the edible films.The protein content of the edible films increased after adding egg white at the 1.5% level (Treatment B).The results of the study are in line with Lestari et al. (2020) where the whey edible film protein obtained is 3.70%.The increase in protein content of the edible films is attributed to the protein content present in egg white, contributing to the whey edible films which also contain protein.The protein content of egg white in this study was 9.33% and whey protein was 0.91%.
According to Wu (2016), egg white consists of various protein components such as Conalbumin (12-13%), ovomucoid (11%), (3.4%), ovomucin (1.5-3.5%), and other minor proteins.Manab et al. (2017) added that albumen proteins contained 54% ovalbumin, 13% conalbumin, 11% ovomucoid, 3.5% lysozyme (G1-globulin), 4% G2-globulin, 1.5% ovomucin, 0.8% flavoprotein, 0.5% ovoglobulin, 0.1% ovoinhibitor, 0.5% ovomacroglobulin, and 0.05% avidin.Ovalbumin, a major protein in egg white, can react with other proteins such as whey during the edible film manufacturing process.When heated, proteins in egg white and whey can denature, making proteins more reactive and capable of forming new bonds with other proteins.Ovalbumin, the main protein in egg white, and beta-lactoglobulin, the main protein in whey, can form a stronger threedimensional network when denaturation occurs.Egg white and whey proteins are rich in functional groups that can form hydrogen bonds with each other.These bonds help stabilize the protein tissue structure in edible films.This aligns with Han (2005) suggestion that a combination of egg white and whey proteins produces edible films with good mechanical and barrier properties.The protein content obtained in this study is nearly consistent with Lestari (2020) who produced whey edible films with protein contents of 3.70%.

Elongation
The results of the variance analysis indicate that the addition of egg white significantly affects (p < 0.05) the elongation of the edible film as per the study findings.Treatment D (4.5%) exhibited the highest elongation percentage.The high film elongation in treatment D is attributed to the presence of ovomucin, which plays a role in increasing the elongation percentage in edible films.According to Manab (2017), albumen contains ovomucin, comprising 1.5-3.5% of the total egg white protein, and contributes to the formation of strong and flexible gel properties, thereby enhancing elongation.Ovomucin, a glycoprotein, can form a gel matrix through interactions with water and other proteins.This matrix binds water and protein molecules, contributing to improved elasticity and flexibility of the film.This aligns with the findings of Huang et al. (2022), who noted that ovomucin in egg white significantly contributes to the mechanical properties of films, including elongation, due to its ability to form a strong and flexible gel network that enhances physical durability.
Another factor influencing elongation is the plasticizer added to the edible film, which alters the mechanical properties of the constituent materials, resulting in a more elastic, flexible, and smooth film.Hasnelly et al. (2015) found that the addition of plasticizer reduces intermolecular forces between polymer particles, resulting in a more flexible edible film.The results of this study surpass Juliyarsi et al. (2021) study on whey-based edible films with elongation percentages ranging from 28.43% to 34.16%.Differences in elongation percentages from previous studies are attributed to variations in additional materials used in edible film production, influencing the constituent components of each additive.This study meets the standards set by the Japan Industrial Standard (JIS) Z: 1707: 2019, where edible film elongation is considered good if it exceeds 10%, but does not yet meet the criteria of Firdaus (2016), who stated that excellent elongation values should be above 50% and not less than 10%.

CONCLUSION
Based on the research findings, the addition of egg white has effect on the thickness, dissolution and disintegration time, water vapor transmission rate, elongation, and protein content but does not affect the water content of edible films.The addition of egg white as much as 1.5% gives the best results.

Figure 1 .
Figure 1.Whey edible film with the addition of egg white

Table 1 .
Characteristics of whey edible film with added egg white d Note: The letters abcd indicate significant differences (p < 0.05).