INTRODUCTIONCheese production process has significant impact onthe environment. One of damaging factor is the disposalof cheese by-product. Cheese making process produceslarge amounts of by-product called cheese whey, whichis almost 90% of used milk [1]. It implies if one batchof cheese production uses 100 L o f m ilk, 8 0–90 L ofcheese whey will be produced [2]. Although it is wasted,30% of cheese whey still has been utilised as animalfeed and fertiliser, while the rest has thrown away tothe rivers or seas [3]. Cheese whey is able to damage theenvironment due to its characteristics. Cheese whey hashigh biochemical oxygen demand (BOD) and chemicaloxygen demand (COD), which is more then 35000 and60000 ppm, respectively [4]. Thus, 4000 L of whey fromthe cheese industry can damage the environment to thesame extent as faecal waste from 1900 humans [5].On the other hand, whey has a valuable chemicalcomposition and contains 55% of total nutrients inmilk [6]. Whey contains (w/w): 93.7% of water, 0.1–0.5%fat, 0.8% protein, 4.9% lactose, 0.5–0.8% ash, and0.1–0.4% lactic acid [2]. Functionally, the beneficialeffect of whey on the human health is due toimmunoglobulin and glycoprotein, such as lactoferrinand transerin, as well as enzymes – lysozyme andlactoperoxidase. All of these components contributeto human immunity and have an antimicrobial activityagainst allergy reaction [7, 8].Cheese whey has been utilised in various ways.About 70% of whey is processed into whey powderthat can be used in pastry, ice cream, sweets, glazes,sugar dressing, jams, and melted cheese industry [3, 9].Whey is used as a food ingredient because of its gelling,emulsifying, antimicrobial properties, good solubility,viscosity, nutritional value, as well as the ability toreduce allergenicity [2, 10]. Unfortunately, it is difficultto utilise whey for cheese manufactures [11]. One of thecauses is high cost drying process of whey. Therefore, thesearch of alternative whey processing is of great interest.Organic compounds of whey are a potentialbiomass to be utilised as bio-energy. Bioethanol canbe made from whey through fermentation by usingKluyveromyces fragilis var marxianus [11–13]. Lactose,12Dinika Isfari et al. Foods and Raw Materials, 2019, vol. 7, no. 2, pp. Х–Хwhose content in whey is 4.5–5%, acts as a carbonsource for ethanol fermentation. The fermentationalso can result in various bioproducts, such as ethanol,biogas (methane), organic acids (acetic, propionic, lactic,citric, and gluconic), amino acids (glutamic, lysine,and threonine), vitamins (B12 a nd B 2), polysaccharides(gum, dextran, and gellan), lipids, enzymes(polygalacturonase), and others (calcium magnesiumacetate, butanol, and glycerol) [11].The fermentation of whey leads to other compoundswhich have high functional use, such as bioactivepeptides. Native whey has minor bioactive compoundssuch as lysozyme, lactoperoxidase and lactoferrin thatare reported to have antimicrobial activity towardspathogenic bacteria [7]. Fermentation causes proteinhydrolysis – by a microorganism which releasesbioactive peptides from protein molecules or by adigestive enzyme, such as proteases [14, 15].Cheese whey can also be utilised as biodegradablepackaging material, such as edible film. Such a film issafe to consumers and environmentally friendly. It is alsoexpected to extend the shelf life of food products becauseit protects them from gases, such as oxygen, carbondioxide, and ethylene, as well as from water loss [16–18].The use of the edible film as a food packagingmaterial is expected to reduce plastic waste. Annually,Indonesia produces 3.22 million metric tons of plasticwaste. It is the second largest plastic waster after Chinathat produces 8.82 million metric tons. The use of plastichas rapidly increased since the development of plasticcommercialisation in the 1930s and 1940s. It reached288 million metric tons of global plastic resin productionin 2012 [19].The high rate of population growth has causedan increase in food demand. This has resulted in anincreasing use of plastic, which contributes to theeconomic benefits [20, 21]. Food industry still widelyuses non-degradable plastic as a food packagingmaterial. However, non-degradable plastic, such aspolyethylene (PE), has an immensely slow degradationtime under natural environmental conditions [22–24].Thus, food industry indirectly affects the environment.The utilisation of cheese whey to produce bioproducts,such as edible films, would be a potentialcourse of action to protect the environment. Cheesewhey fermentation can be applied to enhance theantimicrobial effect and the packaging ability of theedible film produced in order to extend the shelf life ofpackaged food. The aim of this paper was to review thepotential of fermented cheese whey in the produce ofedible films and active packaging systems.STUDY OBJECTS AND METHODSThe paper was written with non-researchmethodology based on literature reviews from varioussources.RESULTS AND DISCUSSIONFermented cheese whey. The protein content inmilk is 3.5% which is, in turn, composed of 80% ofcasein (α-, β-, and k-caseins) and 20% of whey proteins(β-lactoglobulin, α-lactalbumin, and others). Severalproteins in milk have an antimicrobial effect as shownin Table 1 [31, 33–38]. Whey contains biological activesubstances, such as enzymes, trace elements, andimmunoglobulins which contribute to the good health [25].Table 1 Antimicrobial peptides in milkSource Protease Peptide TargetAntimicrobial peptides from caseinBovine αs1-casein Chymosin Caseidin Gram-positive bacteriaChymosin,ChymotrypsinIsracidin αsl-CN (f l–23) Staphylococcus aureusBovine αs2-casein Trypsin Casoidin-I f (150–188) Gram-positive and gram-negative bacteria, yeastChymosin Casoidin-I f (181–207) Gram-positive and gram-negative bacteriaβ-Casein Trypsin andchymotrypsinβ-Casein-derived peptides Enterococcus faecium, Bacillus megateriumAntimicrobial peptides from wheyβ-lactoglobulin Trypsin β-lactoglobulin f (15–20) Gram-positive bacteriaTrypsin β-lactoglobulin f (25–40) Gram-positive bacteriaTrypsin β-lactoglobulin f (78–83) Gram-positive bacteriaTrypsin β-lactoglobulin f (92–100) Gram-positive bacteriaLysozyme Synthetic Lysozyme D52S-Lz (from yeastin egg white)Staphylococcus aureus and Bacillus subtilisLactoferrin Pepsin Lactoferricin B f (17–41) Escherichia coli, Listeria monocytogenes,viruses, fungiPepsin, chymosin Lactoferricin B f (1–16) E. coli, Micrococcus flavusPepsin Lactoferricin C f (14–42) M. flavusSynthetic Lactoferrampin/BL fampin f (268–284) C. albicans, E. coli, Bacillus subtilis,and Pseudomonas aeruginosa40)13Dinika Isfari et al. Foods and Raw Materials, 2019, vol. 7, no. 2, pp. Х–ХFermented whey is known to exert antimicrobialproperties. For example, Bacillus licheniformis canproduce 3200 AU/mL of bacteriocins from 70 g/L ofcheese whey. This amount can count over 4000 AU/mLif cheese whey increases up to 120.4 g/L (with initialpH of 7 and incubation temperature of 26–37°C). [26].Bacteriocins are a bacterial peptides which are able toinhibit or kill microorganisms [27]. Other lactic acidbacteria, such as Lactococcus lactis, Lactobacilluscasei, and Leuconostoc mesenteroides, also can producebacteriocins in response to whey fermentation [28–30].Besides bacteriocins, fermented whey containsbioactive peptides which also have antimicrobialactivity. Bioactive peptides defined as inactive fragmentsof precursor protein sequences. Proteolytic enzymescan release the fragments, and they can interact withselected receptors and regulate the body’s physiologicalfunction [31]. Table 2 demonstrates bioactive peptidescontained in whey protein [50–55]. β-lactolobulin,α-lactoalbumin, immunoglobulin, bovine serumalbumin, bovine lactoferrin, lactoperoxidase and minorproteinaceous, such as glycomacropeptide, are releasedfrom k-casein during enzymatic cheese making [32].Along with antimicrobial effect, whey bioactivepeptides act as immunomodulatory agents that regulatecell-mediated and humoral immune functions [31].In addition, bioactive peptides inhibit angiotensinconvertingenzyme (ACE) that splits angiotensin I toangiotensin II, an active peptide hormone. These peptidesare able to inhibit ACE and control the increase in bloodpressure [39]. Opioid peptides influence the central orperipheral nervous system that involved in hypotension,reduced appetite, fluctuating body temperature andalteration of sexual behaviour [40, 41]. Also, peptideswith antioxidant activity which can protect the cell fromfree radicals has been detected [42].Bioactive peptides can be released in three ways:gastrointestinal digestion (in vivo), fermentation(in vivo), and hydrolysis (in vitro) [31]. Release ofbioactive peptides in gastrointestinal tract is the resultof enzymatic action. The enzymes are pepsin, trypsin,or chymotrypsin. Pepsin, which is produced frompepsinogen by hydrochloric acid (HCl), convertedprotein to peptides and amino acids [43]. Other enzymes,such as alcalase and thermolysin, can also stimulategastrointestinal digestion to produce ACE inhibitorypeptides, as well as anti-bacterial, anti-oxidative,immunomodulatory, and opioid peptides [44–49].Other ways to produce bioactive peptides aremicrobial fermentation and hydrolysis. For microbialfermentation, such LAB as Lactococcus lactis andLactobacillus helveticus are used. Microbes willuse distinct intracellular peptidases including endopeptidases,amino-peptidase, di-peptidase, andtri-peptidase [33]. Hydrolysis of protein molecules canis performed by proteinases, which leads to the releaseof bioactive peptides. Proteinases are obtained from thesecretion of the bacterial and fungal sources [31].Bioactive peptides produced from fermented whey canbe purified to enhance their functional activities. Stepwisefiltration can be carried out to extract bioactive peptidesafter fermentation. Afterwards, the extract is centrifugedat 7000 rpm for 10 min in a refrigerated centrifugeto obtain supernatant. The supernatant is filteredthrough 0.45 μm and then through 0.22 μm syringefilters. Ultrafiltrate of bioactive peptides of 10 kDaand 5 kDa in size can be obtained after passing throughthe 10 kDa and 5 kDa MWCO membranes [56].Edible film production. Food products usuallyhave a short shelf-life. In order to prolong it, most ofmanufacturers uses food packaging. A packaging systemshould protect the product from contamination duringhandling, storage, and sale until it reaches retailers andconsumers [57]. Non-degradable packaging still haswidely applied by food industry. The US EnvironmentalProtection Agency (EPA) reports that 31% of municipalsolid waste (MSW) is packaging waste [58]. Ediblefilms as a packaging material can be an effectivesolution of reducing waste because of their degradablecharacteristics [57].The ideal edible film has high water holding ability;controls gas exchanges; inhibits solute transport,organic vapour transfers, as well as oil and fatmigration; improves mechanical properties of foodto simplify handling and carriage; has neutral sensorycharacteristics, improving sensory properties of foodTable 2 Bioactive peptides derived from whey proteinsName Peptide sequence Fragment Functionα-Lactorphin Tyr-Gly-Leu-Phe 50–53 Opioid agonist, ACE inhibitionβ-Lactorphin Tyr-Leu-Leu-Phe 102–105 Non-opioid stimulatory effect on ileum,10–105 ACE inhibitionβ-Lactotensin His-Ile-Arg-Leu 146–149 Ileum contraction, opioidSerophin Tyr-Gly-Phe-Gln-Asp-Ala 399–404 OpioidAlbutensin A Ala-Leu-Lys-Ala-Trp-Ser-Val-Ala-Arg 208–216 Ileum contraction, ACE inhibitionLactoferricin Lys-Cys-Arg-Arg-Trp-Glu-Trp-Arg-Met-Lys0Leu-Gly-Ala-Pro-Ser-Ile-Thr-Cys-Val-Arg-Arg-Ala-Phe17–42 AntimicrobialGlycomacro peptide(GMP)– 106–169 Food intake regulation14Dinika Isfari et al. Foods and Raw Materials, 2019, vol. 7, no. 2, pp. Х–Хproducts [57]. Edible films should consist of componentsproduced mainly from edible biopolymers and foodgrade additives. The additives should meet safetyrequirements to food additives and to be at least GRAS(Generally Recognized as Safe) [59].There are two ways to create an edible film: wetprocess and dry process. Wet process applies dispersionin a solvent such as water, alcohol, or mixture of waterand alcohol, or other solvents. The film-forming solutionis then casted and dried to obtain films. The dry processdoes not require any solvent. It can be produced bycompression, molding, or extrusion [60, 61]. Thefilm-making and coating processes include meltingand solidification of solid fats, waxes, and resins;conservation of hydrocolloid; complex conservation oftwo hydrocolloids; and thermal gelation or coagulationby heating [57]. Therefore, the dry process usually needsmore equipment, which results in higher cost comparedto the wet process.In edible film production, the incorporation of acertain additive is possible to form an advanced systemcalled active packaging [62]. The additive compoundenhances shelf-life and stability of the product, as wellas improves its microbiological safety and sensoryattributes [63]. The following additives can be used inedible films: flavouring agents, spices, antimicrobialsubstances, antioxidants, pigments, light absorbers,salts, etc. Antioxidants and antimicrobial additivesare commonly used in order to prevent spoilage andthus enhance safety. Antimicrobial agents, beingused in active packaging, can overcome the hurdlesof uncontrolled migration and interaction of an activecompound of various natural antioxidants used directlyin food [64, 65].Comparison of characteristics from various filmbases. Edible film or even active packaging usuallyuse polysaccharide, protein, lipid, or composite base tomake a film forming solution. Thus, fermented whey canbe one of multifunctional ingredients and act as a filmformingbase and an antimicrobial agent.Researchers have focused on the use of compositebased films to explore the complement advantagesof each component [64, 66]. A composite based filmcan be both one-layer and multiple-layer. The matrixof hydrophilic and hydrophobic lipid, which is calledbi-layer composite system, has better functionalcharacteristics than pure hydrocolloid films. However,one of disadvantages of bi-layers composite systems islonger preparation process. It requires two casting andtwo drying stages, which has made these laminated filmsless popular in food industry [67]. In order to enhanceholding properties of active packaging, scientists havestudied its mechanical properties (table 3). These aretransparency, oxygen permeability, carbon dioxidepermeability, water vapor permeability, emulsionstability, and glass transition temperature.Generally, lipid films have the less structuralintegrity compared to protein or polysaccharidefilms [68]. The use of lipids in edible films has resultedin heterogenous film structure that has an impact ondiscontinuities in the polymer and production of astrong emulsion matrix [69]. A composite film based onpolysaccharide has the greatest mechanical properties,which allows its using in gastronomy. Along withprotein added, polysaccharide film is an optimal activepackaging.Besides the film based component, the compositionof the edible film is also an important factor. Plasticizeris one of substantial components to create a flexible filmby reducing interaction between intermolecular starch[70]. Examples of plasticizer are polyol groups such asglycerol, xylitol, sorbitol, mannitol, and sucrose [18,70]. Xanthan gum and carrageenan are also promisingplasticizers which provide the product with strengthand durability with great sensory properties. Theydemonstrate high stabilizing ability and resistanceto water, [71]. The plasticizer is able to reduceintermolecular bonds between amylose, amylopectin, andamylose-amylopectin in the starch matrix and replacethem with hydrogen bonds between plasticizer andstarch. This reduces brittle and enhances flexibility [68].Table 3 Edible film characteristicsCharacteristic Effective componentsfor base makingIneffective componentsfor base makingAdditional info SourceMechanicalpropertiesFlexibility and texture offilmComposite, purehydrocolloid matrixLipid (good in coating,bad in film)[72]Transparency Lightness and colourlessof filmEmulsified films withlipid– The higher lipid content,the less lightness[73]OxygenpermeabilityO2 transfer through film Hydrocolloid, protein Hydrophobic [74][75]Carbon dioxidepermeabilityCO2 transfer through film Cellulose films,proteinLipid (stearic acidand palmitic)The higher lipid content,the weaker barrier[76]Water vapourpermeability(WVP)Moisture transfer throughfilmHydrophobic (lipid) Polysaccharide, Protein Better at smaller andmore homo-genous lipiddistributed[77][78][79]Water solubility(WS)Lower WS needed to protectfood from moisture lossLipid – Lipids reduce WS [80]15Dinika Isfari et al. Foods and Raw Materials, 2019, vol. 7, no. 2, pp. Х–ХTable 4 Characteristics of composite film basesBase Added component Method of making Thickness,mmWVP,g/m·s·PaWater solubility,%Tensile strength,MPaElongationat break, %SourceNative wheat starch,whey protein isolateGlycerol Dissolving (separately), heating at shaking(separately, 85°C, 30 min), cooling, mixing,drying (25°C, RH 40%, 24 h), peeling, storing(RH 53%, 25°C, 7 days).0.109 ± 0.008 7.95 ± 0.33(RH 30–100%)10.53 ± 3.80 4.67 ± 0.19 76.26 ± 8.92 [84]Soya protein(defatted), papayapuree (pectin)Starch, glycerol, gelatin Papaya puree film production (mixingPP + 0,07 ± 0,005 water + starch, dissolved at75°C, 30 min), mixing & stirring (separately,30 min each), mixing, casting, drying (40°C,RH 23%, 18 h), peeling, storing 48 h0.119 ± 0.002 5.55 ± 0.43(g·mm/m2·h·kPa)82.26 ± 0.27 6.80 ± 0.08 22.23 ± 0.06 [85]Almond oils, wheyprotein isolateGlycerol Dissolving WPI (250 rpm, 80°C, 30 min),cooling, mixing (13500 rpm, 5 min), casting,drying (25°C, RH 50%, 24 h), peeling, storing(RH 53%, 25°C, 48 h)0.07 ± 0.005 11.00 ± 1.60 46.90 ± 0.69 5.40 ± 0.80 53.70 ± 7.7 [86]Soya protein, acetem(hydrogenatedsoybean oil)Vegetable glycerin, tween 60(polyoxyethylene sorbitanmonostearate) as a surfactantEmulsification (mixing, 300 rpm, 25°C,30 min), mixing (1 h), heating (90°C,45 min), mixing (1300 rpm, 2 h),degassing, casting, drying (15 h, 24°C)0.113 ± 0.008 2.70 ± 0.46(g·mm/m2·h·kPa)– 2.15 ± 0.18 342.4 ± 25.2 [87]The flexibility of the film depends on theconcentration of the plasticizer in fthe ilm-formingsolution.High or low concentrations would result in antiplasticization.For example, glycerol in the amount ofover 30% used in the starch-based film is the case. It willresult in a decrease in such characteristics as elongationat break. It was established that strong interactionbetween plasticizer and other molecules blocked themacromolecular mobility [70, 81]. On the other hand, ifthe plasticizer concentration is too low, the film formedwill be brittle and hard to handle. Generally, the optimalconcentration of plasticizer is 20–45% [82].The potential of fermented whey for activepackaging composite. The composite of edible filmcan be made to complement each single material-basedfilm characteristics. Protein is usually used as one ofmaterial-based because of its nutritional value [83]. Thecomparison of the composite edible film using proteinbasedis shown in Table 4. From all of the sources ofprotein, soya and whey have been mostly used.As a food barrier capability, the addition of oilhas resulted in a lower WVP, which is showed in acomparison of soya protein with oil and with pectin.Thereby, we can conclude that a composite protein filmwith oil has better barrier properties. However, the watersolubility of whey protein with starch is higher thanthat of soya protein with pectin. In terms of mechanicalproperties, whey protein with starch provides a betterresult than soy protein with pectin. However, someother parameters cannot be compared because of thedifference between the film production and the analysismethod. Based on the description above, it is possibleto conclude that the whey protein is more effective thansoya protein to produce the edible film.Functional characteristics of fermented wheymake it promising raw material for active packaging.Bioactive peptides from fermented whey have hadtheir ability to act as an antimicrobial agent; immunomodulatorypeptides regulate cell-mediated andhumoral immune functions; ACE inhibitory peptideslower blood pressure; and opioid peptides are effectiveagainst hypotension, lack of appetite, etc., as well asexhibit antioxidant properties, protecting cells from freeradicals [31].Several bioactive peptides derived from wheyprotein are also known for its capability to enhance thedefence towards various pathogenic bacteria and yeast.Their antimicrobial activity can inhibit the growth ofsuch microorganisms effectively. The incorporationof bioactive peptides into film is more effective way tolower the concentration of microorganisms than directusing them in food. Thus, it allow avoiding unwantedflavours and odor of food [88].In terms of the characteristics, a good characteristiccan be achieved if the protein contained in the cheesewhey is mixed with starch that contained polysaccharides.With the addition of plasticizer, this composite basedfilm will have good mechanical properties as well as thebarrier ability to prolong food shelf-life.16Dinika Isfari et al. Foods and Raw Materials, 2019, vol. 7, no. 2, pp. Х–ХAdvanced process to create composite fermentedcheese whey film. Nowadays, an advanced processto create an edible composite is based film-formingsolution. The film with cellulose, whey and sunfloweroil based are stirred with Ultraturrax homogenizer at11000 rpm for 3 min to decrease the droplet sizes ofoil. As a result, the smaller droplet sizes can disperseuniformly in the hydrocolloid matrix. Therefore,the penetration of water into film will be harder,which will result in better water vapour transfer.The combination of the degassed method undervacuum (80 kPa) and a vacuum pump for 5 minwill result in the film production with tensilestrength of 8.59 MPa, elongation at break 35.94%,WVP 3.211 g/m·s·Pa, and transparency of 3,637 % [79].There are several methods available to increasethe stability and the quality of characteristics of activepackaging. The addition of enzyme is one of methodsto enhance the film quality in the complex edible film.The presence of Transglutaminase (TGase) has causedenzymatic cross-linking in P/P soluble electrostaticaggregates. Thus, TGase can strongly producecomposite bioplastics by escalating the mechanical andbarrier characteristics. Supramolecular structure of P/Pcomplex as enzyme substrate is crucially influencingpH of a film-forming solution. With the addition ofTGase, film characteristics at pH (pH complexationaround 3.25–5.5, when soluble P/P complexes occur)create better characteristics than higher pH. The pH cansignificantly increase tensile strength and elongation atbreak, and reduce Young’s modulus and WVP [89].For the usage of fermented cheese whey in theactive packaging, there is an advanced process thatcan be added in the fermentation process. Candidasp. is one of the yeast that has already found in SerroMinas, a cheese from Brazil [90]. Recently, a studyfor identifying the indigenous yeast that containedin homemade mozzarella whey has also found thatCandida sp. contained in mozzarella whey and Greekfermented whey [91]. It means that Candida sp. isnaturally contained in cheese whey and can live toferment the whey [92]. Candida spp. is also knownas the most massive yeasts to produce xylitol with63–70% w/w yields. According to several studies,C. tropicalis mutant maximises the xylitol production,reaching 100% yields [93]. It is known that xylitolis one of sugar alcohol that can be utilized in the filmproduction as a plasticizer [18]. Fermented cheese wheycan act as an antimicrobial agent and natural plasticizer.Prospects of the use of edible films and activepackaging with cheese whey. The edible film can bean effective solution to reduce plastic waste of foodpackaging. Addition of several antimicrobials canalso be used to prolong the shelf life to reach a properpackaging system which is similar to the plasticpackaging. Thus, fermented cheese whey as a baseingredient of composite film system is able to meet thisrequirement. Despite some disadvantages of protein, itscombination with other ingredients make is possible toobtain an excellent film with required characteristics.Besides various modification of film manufacture,the cost in creating edible film must be taken intoaccount. The edible film should be cost-effectivecompared to plastic, paper, or any other packaging thatcan harm the environment. Thus, advancing the ediblefilm production is important to make film characteristicsas high as characteristics of plastic packaging.The simplified process of cheese whey fermentationusing indigenous yeast can also increase theantimicrobial properties of the fermented cheese whey.In the future, advancing film manufacture process fromfermented cheese whey can be one of massive ways tocreate modern environmentally-friendly packaging.CONCLUSIONCheese whey, a by-product of cheese-makingprocess, has several functional effects, includinginedible film formation. Bioactive peptides containedin native cheese whey can be enhanced by fermentationto generate high antimicrobial activity. In addition, acomposite edible film can be produced from fermentedwhey and starch to gain good mechanical characteristicsas well as a good barrier to prolong food shelf-life. Theutilisation of fermented cheese whey as an edible filmmaterial allows obtaining an active packaging systemwith high antimicrobial activity.CONFLICT OF INTERESTThe authors declare no conflict of interest.ACKNOWLEDGEMENTAuthors thank the Ministry of Research, Technologyand Higher Education of The Republic of Indonesia thatfunded the research through ‘Penelitian Tesis Magister’,2019. This article’s publication is supported by theUnited States Agency for International Development(USAID) through the Sustainable Higher EducationResearch Alliance (SHERA) Program for UniversitasIndonesia’s Scientific Modeling, Application, Research,and Training for City-centered Innovation andTechnology (SMART CITY) Project, Grant #AID-497-A-1600004, Sub Grant #IIE-00000078-UI-1.