Biodegradable Packaging Applied to Dairy Products
Lia Noemi Gerschenson Rosa Jagus2 and Carolina Patricia Olle Resa2,3
- 1 Industry Department, School of Natural and Exact Sciences, Buenos Aires University (UBA), Buenos Aires, Argentina
- 2 Laboratory of Industrial Microbiology, Department of Chemical Engineering, Engineering School, Buenos Aires University, Buenos Aires, Argentina
- 3 Fellow of the National Research Council of Argentina (CONICET), Argentina
- 4 Member of CONICET, Argentina
Dairy products are highly prone to oxidation and microbial growth and require packaging with low oxygen permeability to assure shelf life. Light-induced oxidation can cause discoloration, formation of off-flavors, nutrient loss, and water evaporation. Traditional food packaging originates persistent wastes, generating a negative environmental impact. Biodegradable polymers are friendly alternatives to conventional nondegradable polymers. In this chapter, the recent research concerning biobased biodegradable packaging for application to dairy products is revisited, and challenges are evaluated in relation to the maintenance of biodegradability and safety while improving packaging characteristics.
Fresh cheeses are packaged in modified atmospheres with N2 and/or CO2. However spoilage caused by yeast and especially bacteria may still occur, even at very low O2 and elevated CO2 levels. Semi-soft and hard cheeses have a relatively high respiration rate, which require a packaging material permeable to CO2 to avoid blowing of the packaging. Oxygen must be kept out to avoid fungal spoilage and oxidation of the cheese. Mold-ripened cheeses, such as Brie cheese and blue-veined cheeses, require a balanced oxygen and carbon dioxide atmosphere to prolong shelf life. They need certain oxygen pressure because they contain active fungal cultures, and their anaerobic respiration must be precluded to avoid the production of off-flavors as well as changes in the microbiota (Petersen et al., 1999).
Primary packaging materials are in direct contact with foods, and their functions are to contain, protect, and facilitate distribution and storage of foods. The properties of the primary packaging materials must be complimentary to the requirements set by the packaged foods. Secondary packaging is often used for physical protection of the product. It may be a box surrounding a food packaged in a flexible plastic bag. Tertiary
Advances in Dairy Products, First Edition.
Edited by Francesco Conto, Matteo A. Del Nobile, Michele Faccia, Angelo V. Zambrini, and Amalia Conte. © 2018 John Wiley & Sons Ltd. Published 2018 by John Wiley & Sons Ltd.
packaging incorporates the secondary packages in a final transportation package system to facilitate storage and handling (Food Biopack Project, 2000).
Persistent plastic wastes coming, for example, from food packaging are raising global concern. As disposal methods are limited, their environmental impact is a menace. Incineration may generate air pollution, landfill sites are limited, and recycling methods are expensive and often energy-intensive. These facts, along with the finitude of petroleum resources, illustrate the importance of finding plastic substitutes. Research about biodegradable polymer alternatives is, as a consequence, a must (Mitrus et al., 2010).
According to European Bioplastics Association, bioplastics are biobased, biodegradable, or both (European Bioplastics, 2014). Biobased biodegradable plastics are produced from natural origins (plants, animals, or microorganisms). Natural rubber as well as certain polyesters either produced by microorganism/plant (e.g., polyhydroxyal- kanoates and polyhydroxybutyrate) or synthesized from bioderived monomers (e.g., polylactic acid) fall into this category. Petrochemical-based biodegradable plastics such as aliphatic polyesters are produced by synthesis from monomers derived from petrochemical refining, which possess a certain degree of inherent biodegradability (Song et al., 2009). The term biodegradable refers to a chemical process during which microorganisms that are available in the environment convert materials into natural substances such as water, carbon dioxide, and biomass. The process of biodegradation depends on the surrounding environmental conditions, on the material itself, and on the application (European Bioplastics, 2014).
One challenge facing the food packaging industry in its efforts to produce biobasedprimary packaging that is biodegradable is to match the durability of the packaging with product shelf life. The biologically based packaging material must remain stable without changes of mechanical and/or barrier properties and must function properly during storage until disposal. Subsequently, the material should biodegrade efficiently. As a consequence, environmental conditions conducive to biodegration must be avoided during storage of the food product, whereas optimized conditions for biodegration must exist after discarding (Petersen et al., 1999).
To improve packaging characteristics, various composites containing natural components (often called biocomposites) have been developed. The composite is formed by a polymeric matrix and fillers, which improve the chemical or mechanical properties of the material or make it less expensive. In biocomposites, various natural fibers like hemp have been used (Sawpan et al., 2011). Nonmodified natural fillers are, by definition, biodegradable, as needs to be the matrix polymer (e.g., polylactide filled with natural fibers) for us to say that the biocomposite is biodegradable. Inorganic fillers are, of course, not biodegradable, and therefore the biodegradability condition does not apply to them (Li and Chang, 2005; Bargmann et al., 2013). In many cases, the development of composites has involved the use of nanoparticles (Fortunati et al., 2014). In relation to this, it must be considered that members of the European Parliaments Health and Environment Committee rejected on November 24, 2014, a Commission proposal that would have allowed the use of nanoparticles in foods. Nanomaterials currently do not have any special regulation under EU law (Scott-Thomas, 2014).
Edible coating and films comprise a unique category of biobased packaging materials characterized by its edibility. Edible coatings are applied and formed directly on the food product. Edible films are freestanding structures, formed and later applied to foods. Primary packaging is packaging where the material and food may be separated from each other. Thus, edible coatings do not fall into the primary packaging category. However, edible films may perform similar functions to primary packaging (Food Biopack Project, 2000). Active food contact materials absorb or release substances in order to improve the quality of packaged food or to extend its shelf life (EFSA, 2014). As a consequence, it performs a role other than providing an inert barrier to external conditions. It could involve the inclusion of an oxygen scavenger or of an antimicrobial agent if microbial growth is the quality-limiting variable (Food Biopack Project, 2000).
The Life Wheypack European Project is headed by the Ainia Technological Center, and its objective is the obtention of 100% biodegradable packaging for dairy products using the whey byproduct from cheese making. For this, the team of researchers are developing a microorganism fermentation process to produce polyhydroxibutyrate from whey, which will then be used to manufacture the new packaging (GISOWASTE, 2014).
The Biobottle project is a European Project in the Seventh Framework Programme being carried out by seven companies and technological centers of five European countries. Its objective is to create biodegradable material for dairy packaging. The project is developing a material for making big multilayer bottles, for milk or milkshakes, and monolayer smaller bottles for probiotic products. These materials must be biodegradable and resistant to sterilization and pasteurization. Using reactive extrusion, they will modify the biodegradable material in the market to improve its processability in conventional extrusion equipment, thermal resistance, and functionality (Arthur, 2014).
The BIOMAT research group has developed a single-layer, biodegradable container from soya byproducts suitable for both liquid and solid oily products. The container is transparent and, at the same time, provides an excellent barrier for keeping out ultraviolet light and gases like oxygen. It can be thermally sealed and is printable. In particular, this group has manufactured an active container with natural antioxidant agents for full fat, fat, or semi-fat cheeses and cheese portions. The packaging makes the product last longer in a good condition, which plays an important role not only in the quality of the product but also in reducing discarded, uneaten food (Garrido et al., 2014; Communication Office of the University of the Basque Country, 2014).