Biorefinery and valorization of food waste and other types of biomass Food loss refers to all food produced for human consumption but not eaten by humans that is any food that is lost in the supply chain between the producer and the market. Food waste refers to food appropriate for human consumption being discarded, whether or not after it is kept beyond its expiry date or left to spoil. Food is wasted in many ways such as: Fresh produce that deviates from what is considered optimal in terms of shape, size and color. For example fresh produce is often removed from the supply chain during sorting operations. Foods that are close to, at or beyond the “best-before” date are often discarded by retailers and consumers. Large quantities of wholesome edible food are often unused or left over and discarded from household kitchens and eating establishments. Algae Food waste Manure Wheat straw Sugarcane bagasse Food waste in a global perspective About 1.3 billion tonnes of food and one-third of the total global food production is wasted each year, costing the world economy about $750 billion Avoidable and unavoidable food waste Food waste severely impact the environment due to emission of greenhouse gases The greenhouse gas emissions associated with food loss and waste come from a variety of sources, including: On-farm agriculture emissions − including from the digestive systems of cows, manure from livestock, onfarm energy use and fertilizer emissions − for producing food that is ultimately lost or wasted. The production of electricity and heat used to manufacture and process the food that is ultimately lost or wasted. The energy used to transport, store and cook food that is ultimately lost or wasted. The landfill emissions from decaying food. The emissions from land use change and deforestation associated with producing food that is ultimately lost or wasted. Overview of multi-dimensional approaches for valorization of food waste to value added bio-based products in circular bioeconomy Schematic pathway of anaerobic (absence of oxygen) fermentation for bio-based products generation Food waste and other types of biomass Schematic illustration of an electro-fermentation device Microorganisms 8 Schematic pathway for biodiesel production from oleaginous microorganisms Biodiesel Transesterification 9 Biorefinery of lignin 11 Biorefinery of lignin Main building blocks of lignin Lignin valorization 13 Bioplastic from food waste valorization Most commercial plastics are synthetic polymers derived from petrochemicals and is a huge environmental problem for the ecosystems as they tend to resist biodegradation and lead to the formation of microplastic or nanoplastic. Polyhydroxyalkanoates (PHA)-derived plastics are attractive because they are compostable and derived from renewables and are biodegradable. P3HB and other PHB’s (see below) are produced by certain microorganisms in response to conditions of physiological stress, mainly conditions in which nutrients are limited. PHB’s are primarily a product of carbon assimilation (from glucose or starch) and are employed by microorganisms as a form of energy storage molecules to be metabolized when other common energy sources are not available. The PHA biopolymer poly-3-hydroxybutyrate (P3HB) is used for bioplastic production Microplastics from synthetic polymers constitute a huge environmental problem Production of bioplastic through food waste valorization Sources for different types of bioplastics/polymers Bioplastic polymer chitin and chitosan Chitosan bioplastic is biocompatible, biodegradable, easily molded into complex shapes, and inexpensive because of the widespread availability of shrimp waste. Because of these beneficial characteristics, the material is a potential replacement for conventional petroleum-based plastic in applications ranging from consumer products to medical uses. Secondary metabolites obtained from micro- and macroalgae and their uses 18 Microalgae Macroalgae 19 Polyunsaturated fatty acids (PUFA) and carotenoids produced by microalgae Reduce risk (preventive effect) for cardiovascular diseases and chronic inflammation Food colorants, pro-vitamin A source, physiological modulators 20 Biosynthesis of prostaglandins (important hormones) ALA GLA Target for many drugs Essential fatty acids Essential for the production of prostaglandins. Humans cannot synthesize these fatty acids. Can only be provided through our diet) 21 General mechanism for inflammation White blood cells (leukocytes) Foreign bodies (antigens, bacteria, viruses, etc.) Release of regulatory proteins (e.g., Nuclear factor (NF) -kB)) Binding of NF-kB to promoter on DNA for the formation of cytokines (e.g., Tumor necrosis factor (TNF-α), interleukin (IL)-6) Increased transcription of DNA into RNA = increased protein synthesis of e.g.,TNF-α, IL-6 TNF-α induce the formation of, for example, cyclooxygenase (COX)-2 and thus the biosynthesis of prostaglandins (important regulatory hormones) Prostaglandins signaling compounds for white blood cell assembly = Inflammation Biosynthesis of prostaglandins, continued 23 COX COX COX Cleavage of phycocyanobilin from phycocyanin (pigment in ‘blue green algae’) for use in food colouring 24 Cyanobacteria (‘blue-green algae’) Reaction mechanisms for cleavage of phycocyanobilin (tetrapyrrole chromophore) by solvolysis. In reactions with methanol R = CH3, and with ethanol R = CH2CH3 25 (A) Yields [mg g-1] of solvolysis reactions with ethanol 96% v/v for different cleavage methods and temperatures. (B) Purity [% w/w] obtained using different reaction methods. (C) Yields [mg g−1] of solvolysis reactions with ethanol 96% (v/v) for different reaction methods and reaction times. Phycocyanobilins produced by solvolysis from phycocyanin HPLC profile of solvolysis extract (sealed vessel) 27 Phycocyanobilins are strong electrophiles being able to react with thiol groups in proteins, which may explain their potential anti-inflammatory and anticancer effect 28 Utilization of fruit and vegetable waste 29 Dietary fibers Dietary fibers constitute the portion of plant-derived foods that cannot be completely broken down by human digestive enzymes but may to some extent be fermented in the gut by bacteria. Dietary fibers have two main components, which are the water-soluble fibers and the water-insoluble fibers: Soluble fibers, which are soluble in water and is readily fermented in the colon into gases and physiologically active by-products, such as short-chain fatty acids produced in the colon by gut bacteria. Soluble fibers are therefore also sometimes called prebiotic fibers, and delays gastric emptying which, in humans, can result in an extended feeling of fullness. Typical examples of soluble fibers are: Arabinoxylan. Is a hemicellulose found in both the primary and secondary cell walls of plants, including woods and cereal grains, consisting of copolymers of two pentose sugars: arabinose and xylose. 30 Dietary fibers • Fructans. Are polymers built up of fructose residues, normally with a sucrose unit. Fructans with a short chain length are known as fructooligosaccharides and the polysaccharides are called inulins. Fructans occur in foods such as agave, artichokes, asparagus, leeks, garlic, onions (including spring onions), yacón, jícama, and wheat. Fructans 31 Dietary fibers Pectin is a heteropolysaccharide, which is present in virtually all terrestrial plants where it helps to bind cells together but is also found in primary cell walls. It consist of the partial methyl esters of polygalacturonic acid and their salts (sodium, potassium, calcium, and ammonia), with a molecular weight of up to 150,000 Daltons. It is produced commercially as a white to light brown powder, mainly extracted from citrus fruits, and is used in food as a gelling agent, particularly in jams and jellies, in dessert fillings, sweets, as a stabilizer in fruit juices and milk drinks as well as in medicine. 32 Dietary fibers Insoluble fibers does not dissolve in water and are inert to digestive enzymes in the upper gastrointestinal tract and provides bulking. Some forms of insoluble fiber, such as resistant starches, can be fermented in the colon. Bulking fibers absorb water as they move through the digestive system, easing defecation. Typical examples of insoluble fibers are lignin, starch/resistant starch, cellulose and some hemicelluloses: Cellulose, is a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wall of green plants, and many forms of algae. Some species of bacteria secrete it to form biofilms. Cellulose is the most abundant organic polymer on Earth. The cellulose content of cotton fiber is 90%, that of wood is 40–50%, and that of dried hemp is approximately 57%. Cellulose 33 Dietary fibers 34 Starch is a form of dietary carbohydrate and is the form in which glucose is stored in plants. Chemically speaking, it is a polysaccharide which is made up of monosaccharides (glucose/sugar molecules) that are linked together. Starch is stored in compact granules consisting of two components amylose (soluble) and amylopectin (insoluble). Resistant starch is resistant to digestion by the pancreatic enzyme, amylase. This means that most of the starch makes it past the small intestine and through to the large intestine where it is used in bacterial fermentation Total dietary fibers (TDF), insoluble dietary fibers (IDF), soluble dietary fibers (SDF) contents in the waste of different fruit and vegetables 35 Major types of secondary metabolites present in some fruit and vegetables wastes 36 Phenolic acids Lignin (stained with blue color) Lignans – dimers of phenolic acids Flaxseed Cereals Flavonoids and stilbenoids Flavonoids 41 Flavonoids OH OH OH OH HO 42 O O GlcO − O-Glc Rha OH Quercetin 3-O OH O -rutinosid (rutin, flavonol) O Luteolin 3- -glucosid (flavon) O OH OH OH OCH3 O GlcO Green tea (Camellia sinensis) HO O OH OH Hesperetin 7-O O -rutinosid (flavanon) OH (+)-Catechin (flavan-3-ol) Flavonoids are widely distributed in plants Flavonoids have been used in the food industry due to their ability to preserve foods, to provide colour and flavour and to make dietary supplements, among other important industrial applications. Citrus fruits such as sweet oranges, lemons, grapefruit, limes, and so on Resveratrol an effect on lifestyle diseases? used as a nutraceutical OH HO OH Resveratrol Peanuts Grapes/red wine 43 Carotenoids Flavoring agents and aroma produced from fruit and vegetable waste using microorganisms (fermentation) Ethyl butyrate Isoamyl acetate Vanillin (R)-(+)- and (S)-(−)-γDecalactone Organic acids produced from fruit and vegetable waste using microorganisms (fermentation) Acetic acid Citric acid Lactic acid Enzymes produced from fruit and vegetable waste using microorganisms (fermentation) Amylase An enzyme that catalyses the hydrolysis of starch into sugars Article review (repetition from September 3) Focus on review of articles and writing of scientific papers Articles are usually composed of an Abstract, Introduction, Materials and Methods (Experimental), Results, Discussion (sometimes combined) and Conclusion/perspective and finally References/ literature. Introduction This is the most important part of an article especially in the writing phase. The introduction should give a relevant background of the study in a broad perspective citing the most important literature within the subject and should contain: (1) aim/purpose of the study and/or (2) a hypothesis that is substantiated by the information given in the introduction. (1) and (2) can instead be replaced by relevant questions and then the article will provide suitable answers to the questions based on the results. Introduction can/should be used as an outline for the whole articles and should have a clear focus. Avoid investigations in the same article that are too different and therefore are not complementary. Materials and Methods Should contain a description of the most important techniques and materials used. Often researchers refer to previous work in order to avoid repetition of well known or previous described methods. Depends also on the journal. Also important that the statistics is properly designed and executed. Article review (repetition from September 3) Focus on review of articles and writing of scientific papers Results Most important results are presented in this part. If the Results and Discussion is not combined the results are not discussed in this part. However, minor comments to the results can be included in this part if relevant. Discussion In the Discussion, the results are discussed in relation to the aim/purpose, hypothesis or questions given in the introduction. In the Discussion section the results are also discussed in relation to the present scientific knowledge in the field by including relevant scientific literature. In addition, the results are sometimes put in a broader perspective. Conclusion The most important results of the scientific study is briefly described and the impact of the results of the study. In an article one should be as correct as possible avoiding typing errors and contradictions, to be consistent in the use of scientific designations and to use them correct, avoid unverifiable statements (speculations) or statements that are not substantiated by the results in the article. In connection with your Critical Review of articles in this course you should focus on: • • • • Significance/contribution to the field Methodology /approach Arguments & use of evidence Writing style & text structure The above points will be addressed and discussed in more detail in some of the other lectures in this course and are important when you prepare you Critical Review for the exam. I admit that most of you do not have the background for evaluating all these points in the article we will discus in my part of the course but at the exam the material/articles you will have to evaluate through a Critical Review the above points will all be relevant. Article reviews of the following articles (online discussions – see also attached notes): Article no. 1 Bioactive Phenolic Compounds from the Agroindustrial Waste of Colombian Mango Cultivars ‘Sugar Mango’ and ‘Tommy Atkins’— An Alternative for Their Use and Valorization. Antioxidants 2019, 8, 41, 1−19. Article no. 2 Vitis vinifera ‘Pinot noir’ leaves as a source of bioactive nutraceutical compounds. Food Funct. 2019, 10, 3822–3827.