Applications of Green Chemistry and Engineering to Food Packaging, Processing, and Post- Production Waste

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1 Tess Carter 10/24/15 From Seed to Shelf Midterm Applications of Green Chemistry and Engineering to Food Packaging, Processing, and Post- Production Waste Ever heard of the term cradle to cradle? In contrast to cradle to grave, which looks at the life cycle of a chemical, cradle to cradle is the idea of using the waste of one process as the feedstock (or starting material) for another and stems from the tenets of sustainable development. Per the Brundtland Commission, sustainable development is a way of doing business that meets our current needs without jeopardizing the ability of future generations to meet their needs (United Nations, 1987). Green chemistry and engineering are two disciplines through which the food industry has begun implementing sustainable development goals. Green chemistry is the practice of chemistry that seeks to minimize adverse impacts on both human health and the environment by increasing efficiency and innovation. The development of green chemistry itself has been rapid from the proposition of the 12 Principles of Green Chemistry in 1998 as a philosophy and framework (Anastas 1998) to the 2005 Nobel Prize in Chemistry, which was presented as a great step forward in green chemistry (Nobel Prize 2005). The green chemistry market is also expected to grow from $2.8 billion in 2011 to $98.5 billion by 2020 while saving industry $65.5 billion according to one often-cited study (Pike Research 2011). Entrepreneurs, academics, and the food industry have taken note of this surging discipline and are now applying its techniques to all part of food production including using renewable feedstocks and safer solvents and designing for degradation and pollution prevention (Anastas 1998). Plant and fungus-based packaging alternatives to plastics and styrofoams have emerged on the market joined by

2 safer, cheaper extraction solvents like supercritical CO 2. Supercritical CO 2 is a state when carbon dioxide is held above its critical pressure and temperature, and thus it will retain useful properties of both a gas and a liquid such as completely filling a container like a gas and having a density similar to a liquid (Hyatt, 1984). Developing the concept of greening the life cycle of products even further, people have begun repurposing the waste from food production processes into value-added products (e.g. transforming citrus waste into chemicals like limonene - a useful fragrance, solvent, and chemical intermediate - and proteins, pectin, and sugars, which all have a multitude of uses) (Luque and Clark, 2013). In the current age of mass production and often global food production, the high production, disposal, and environmental costs of packaging have provided the impetus for scientists to develop bio-based plastics and styrofoam. As opposed to producing plastics from fossil fuel sources, many companies have begun exploring alternative renewable options (Everts (a), 2010). Some companies are even using byproducts of other processes to create new biomaterials. For example, Ecovative produces replacements for plyboard, styrofoam, and fiberboard by binding together refuse like agricultural waste with mycelium, which is essentially mushroom roots. These products are cost-competitive with traditional mediums, naturally fire resistant, rapidly renewable, and home compostable and have many other desirable characteristics (Ecovative, 2015). Thus, it is possible to be renewable and to not sacrifice form or function - by encouraging innovation, even the ubiquitous styrofoam can be replaced by bio-based renewables that take in waste as one of their feedstocks. The biodegradable bags that PepsiCo implemented for their SunChips are another example of bio-based packaging; although, this biomaterial initially was met with resistance from consumers because the bags made louder crinkling noises than traditional petroleum-based

3 packaging (Brokaw, 2014), illustrating the careful balance needed between sustainability, economics, and societal norms and preferences. Using another green chemistry technique to approach a quandary in the food production system, food and drink scientists have begun using supercritical CO 2 to decaffeinate coffee, extract hops and essences, and remove contaminants instead of potential carcinogens like methylene chloride. Because supercritical CO 2 can be used as a solvent at relatively low temperatures and is fairly stable, CO 2 mediates extractions of many compounds with minimal damage. Chemists in research labs also utilize supercritical CO 2 as a solvent and for drug delivery and tissue engineering (Davies et al., 2008). CO 2 is particularly useful in food extraction processes because it is inexpensive, non-toxic, nonflammable and readily available in high purity from a variety of sources (Davies et al., 2008). Where the suspected carcinogen, methylene chloride, was once used to strip away the caffeine to make decaffeinated coffee, companies and scientists now used supercritical CO 2 to do the same extraction. Supercritical CO 2 is now used in over 125 food and drink manufacturing plants globally for a wide range of processes from extracting... essences from ginger root to drawing out pungent oil from sesame seeds and eliminating contaminants in wine corks that can harm its flavor (Everts (b), 2010). By repurposing the waste from some food production processes as the feedstock to make value-added products, the food industry illustrates an effective implementation of green chemistry principles outside the chemistry discipline to solve sustainability issues. Composting and recycling are two well-known and accepted basic valorization strategies for waste globally, but these basic strategies are only partially successful and only recover/convert less than 50 wt.% of the waste into useful products (Luque and Clark,

4 2013). More advanced valorization processes create new products like chemicals and fuels from waste and byproducts through green technologies. Examples abound of successful strategies and methods for transforming the waste of different foods and food processes into useful, needed products like citrus waste, bakery waste, meat and leather waste, and coffee grinds waste. Utilizing a simple approach, citrus refuse can be transformed into a variety of valueadded products, such as chemicals, sources and materials for animal feed, pectin, and sugars, which can subsequently be turned into bioethanol. Simple, efficient microwave radiation facilitates the conversion of citrus residue into value-added goods that are useful in a variety of sectors. Citrus can be transformed into multiple chemicals like limonene (a useful fragrance, solvent and chemical intermediate) and terpineols (Luque and Clark, 2013) as well proteins, pectin, and sugar (Lin et al., 2013), which are all useful in food processes and beyond. Thus, recognizing citrus waste as an opportunity to create new products instead of allowing it to enter the waste stream is an important step in making our food systems more sustainable. Similarly, simple green chemistry techniques can transform the waste from many other food processes (i.e. bakery waste, meat and leather waste, and coffee grinds waste) into value-added products with a range of applications. Taking advantage of the fermentation processes that occur in pastry and bread making, one can select specific microbial strains in the fermentation processes to produce biodegradable polymers, higher level alcohols, and succinic acid (Luque and Clark, 2013), which can be used as a diet and food supplement to regulate acidity and as a precursor for some specialized polyesters and resins. Using a simple acid extraction, meat and leather waste can be used to produce

5 biocollagenic (connective tissue) materials that can help knit together skin and heal wounds (Luque and Clark, 2013). Coffee grinds and other waste sources have also been transformed through fairly simple methods into biodiesel and other fuels (Kondamundi et al., 2008). Baking refuse, meat and leather residue, and coffee grinds are just a few examples of waste produced by the food industry that can relatively easily be diverted from waste streams and instead used as chemicals, fuels, and other value-added products. While many of these innovative packaging techniques, greener solvent systems, and advanced valorization processes are used on a small scale, increased government funding, incentives, education, and regulations could facilitate wider implementation of green chemistry techniques and sustainable development throughout the food production system. Consumer demand and astute businesses catalyzed the initial desire to find more renewable feedstocks and to green many parts of the food industry. Because humans continue to live beyond a sustainable ecological footprint, a true cradle to cradle system with innovations that not only minimize waste but also convert waste into usable feedstocks is essential. While businesses are leading many of these initiatives, educating both the general public and also the next generation of chemists and food scientists in green design and implementation practices is integral for creating awareness and a self-perpetuating system. In addition to better contextualized chemistry education, to send a message that sustainable development is a high priority, it is important to increase government funding for green chemistry and engineering research and development and to alter chemical and food industry regulations. In the future, to better help the environment, society, and economy, green technologies should become the norm instead of novel, side innovations as the food industry continues to modernize.

6 Bibliography: Anastas, P. T. & Warner, J. C. (1998) Green Chemistry: Theory and Practice, Oxford University Press: New York, 30. Brokaw, L. (18 Mar. 2014)"Pepsi's Biodegradable Backlash: The Snack Bag That Was Too Noisy." GreenBiz. Based on MIT Sloan Management Review. Davies, O. et al. (2008) Applications of supercritical CO 2 in the fabrication of polymer systems for drug delivery and tissue engineering. Advanced Drug Delivery Reviews 60(3): Ecovative. (2015) "How It Works." Ecovative. Ecovative. Everts, S. (a) (13 March 2010) "Better Living through Green Chemistry: Packaging." New Scientist. Reed Business Information Ltd., 13 Mar Everts, S. (b) (12 March 2010) "Better Living through Green Chemistry: Food and drink." New Scientist. Reed Business Information Ltd. Hyatt, J. (1984) Liquid and supercritical carbon dioxide as organic solvents. J. Org. Chem. 49 (26): DOI: /jo00200a016 Kondamundi N., Mohapatra S.K., Misra M. (2008). Spent coffee grounds as a versatile source of green energy. J. Agric. Food. Chem. 56: Lin, C. et al. (2013) Food waste as a valuable resource for the production of chemicals, materials and fuels. Current situation and global perspective. Energy Environ. Sci. 6: Luque, R. and Clark, J. (2013) Sustainable Chemical Processes 1(10). doi: / Nobel Media AB (2005) Press Release: The Nobel Prize in Chemistry. Nobelprize.org Jul Pike Research. (December 2011) Industrial Biotechnology 7(6): doi: /ind United Nations (1987) Department of Economic and Social Affairs. Report of the World Commission on Environment and Development. N.p.: United Nations.