FOOD CO-STREAMS FOR INNOVATIVE FOOD AND FEED PRODUCTS

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1 FOOD CO-STREAMS FOR INNOVATIVE FOOD AND FEED PRODUCTS Anne-Kristin LØES 1, Steffen ADLER 2, Randi SELJÅSEN 3, Ana CARVAJAL 4, Guro Møen TVEIT 4, Rasa SLIZYTE 4, Kaisu HONKAPÄÄ 5, Katariina ROMMI 5 1 Bioforsk Norwegian Institute for Agricultural and Environmental Research, Organic Food and Farming 2 Bioforsk, Grassland and Landscapes 3 Bioforsk, Horticulture and Urban Greening 4 SINTEF Fisheries and Aquaculture, Norway 5 VTT Technical Research Centre of Finland Ltd., Finland 1 Gunnars veg 6, N-6630 Tingvoll, Norway 1 anne-kristin.loes@bioforsk.no Abstract. The CYCLE project aims at reducing food loss by creating innovative food and feed products and ingredients, in a close cooperation with the Norwegian food industry. Three important food chains are involved: chicken, white and pelagic fish, and vegetables and potatoes. Bioforsk, VTT and SINTEF cooperate on hydrolisation of chicken co-streams to produce oil and proteins, and to develop healthy food products as well as products with a specialised function from vegetable and potato co-streams. Experience from seafood at SINTEF is brought in contact with food and feed knowledge in Bioforsk and VTT, and a close contact with food industry ensures a high relevance for developed processes and products. The paper presents preliminary results in the development of oil from chicken bones, proteins from chicken feathers, vegetable smoothies and suberin films made from potato peels, as example of food and feed innovations based in bioeconomy. Key words: chicken, CYCLE project, food industry co-streams, protein hydrolysis, vegetables. INTRODUCTION The research project Total utilisation of raw materials in the supply chain for food with a bio-economical perspective (CYCLE) aims at improving the resource utilisation in the Norwegian food industry by developing eco-friendly bio-processes, applying novel technology. The project ( ) involves research institutes from Norway, Finland and Denmark, with social scientists, food technologists and agronomists cooperating closely with industry partners. CYCLE aims at finding new ways to utilise co-streams generated during the processing of food raw materials, and thereby reducing food loss. We develop technologies to transform co-streams to innovative products with a high economic value. The project is funded by the Research Council of Norway with totally 5 million, and included in the program Sustainable Innovation in Food and Bio-based Industries (BIONAER). The project studies three central food chains in Norway: Vegetables and potatoes; white and pelagic fish; and chicken. Efficient utilisation of raw materials in the food sector generally implies that a high proportion is processed to food and feed. According to the waste management hierarchy of the EU [1], avoiding waste generation is the main strategy, followed by re-use, recycling, recovery and disposal of waste. Waste is defined as any substance or object which the holder discards, or intends to discard, or is required to discard [1]. For the food processing industry, utilisation of co-streams for feed or technical applications often gives a lower rate of return than for food applications, or may even be a net cost. However, this net cost may be lower than disposal would cost. With high energy prices and economic support for renewable energy, as found in some European countries like Denmark and Germany, energy production from co-streams by digestion or incineration may be profitable enough to allow for a payment to the industry. In Norway, energy prices are generally low due to the large availability of hydroelectric power. The industry has to pay a fee for waste disposed as landfill or incinerated for destruction by methods which do not include utilisation of the energy. For waste incinerated for energy production, there is no end-treatment fee since October 1, 2010 [2], but local incineration plants may charge a fee for disposal of high-risk animal co-streams. The Norwegian waste classification system comprises the categories recycling, biological treatment (i.e. composting, anaerobic digestion), filling and covering compounds (e.g. for road construction), incineration for energy production, incineration without energy production (i.e. destruction), and landfill. 299

2 The term food loss is used to describe a decrease in edible food mass within part of a food supply chain that leads to edible food for human consumption [3]. Food losses occur throughout the entire food chain, from primary production via postharvest handling and storage, to food processing, distribution, retailing and consumption. Globally, annual food losses are estimated to account for about 1,300 million tonnes, about one third of the total food produced for human consumption [3]. In the Nordic countries, food losses are largest in primary production and households, but losses from the food processing are also significant [4]. In total, 335 to 460 thousand tonnes of food, 62 to 86 kg per capita, are lost annually in Finland by consumers, retailers, food services and food industry [5]. When food is utilised for non-food purposes, we may distinguish between planned and unplanned non-food use. Utilisation for feed, fertiliser or bioenergy production may be a planned non-food use, whereas ploughing down a non-harvested crop may be an unplanned non-food use [3]. Still, both non-food utilisations are included in the food loss. The term food waste is used to describe food losses occurring at retailers and consumers, in the end of the food chain. The terms food loss and food waste only refer to products that are directed to human consumption, and are not used to describe a decrease in the amounts of materials integrated in the raw materials, such as fish skin or potato peel. The term waste does not necessarily refer to the inherent qualities of a co-stream, but is rather a subjective term, as a material may be waste for one user and a resource for another. Therefore, we avoid the term waste in the CYCLE project. Instead, we use the term co-streams to describe all food-processing by-products [6]. Two co-streams from the poultry industry that could well be more efficiently utilised, are minced residues after mechanically deboning of meat (MDM), and feathers. The current utilisation is as feed for fur animals and ingredients in pet food. Both co-streams are rich in protein, and MDM residues also contain high amounts of oil and minerals. The main component of feathers, beta-keratin (95% of dry weight) has a very low digestibility since beta-keratin is resistant to degradation due to disulphide bonds. Keratin can be solubilised by high-pressure boiling, chemical hydrolysis, enzymatic hydrolysis, microbial fermentation or by combinations of these treatments. Globally, 24 billion poultry birds are produced each year. Assuming an average body weight of 2 kg and a feather content of 5%, the total amount of feathers produced is 2.4 million tonnes per year. In spite of this huge amount, only few companies produce feather meal in Europe, applying the standard method of pressure boiling to produce about tonnes of feather meal annually. In Europe, feather meal may only be utilised as feed for pets, fish and fur animals, and as a fertiliser. Typically, feather meal has 70-80% crude protein with a digestibility of 60-70%. Prices vary between 250 and 550 per ton. Research on alternative methods to pressure boiling has shown a potential to improve the digestibility and amino acid composition of feather meal, and at the same time decreasing production costs. However, these revised methods have not yet been adapted to industrial scale, likely related to knowledge gaps and costs. In CYCLE, we aim at developing production methods for feather meal with higher digestibility compared to the standard method. In this paper, we will discuss some observations from an initial experiment to study effects of pressure boiling combined with commercial enzymes on the digestibility of non-solubilised feather keratin. We also present initial results of enzymatic hydrolysis of chicken bones [7], which has been a research topic at SINTEF for some years and is now further studied in CYCLE. From the vegetable industry, second-class products and peelings constitute co-streams that are currently utilised for starch and alcohol production (potatoes), as animal feed or digested for biogas. Sludge (with peels) after washing is disposed as landfill. For such products used as animal feed, the short shelf life poses a problem. Second-class products and leftovers from production e.g. of ready-to-eat, cut lettuce are usually food products of high quality, and people are encouraged by health authorities to eat more vegetables. This calls for innovative utilisation of the vegetable industry co-streams, and in CYCLE we have tested vegetable smoothies. Initial results are presented here. Some co-streams, e.g. potato peels with a high content of suberin, may also possess characteristics that can be utilised in special applications. Suberin is a waxy compound, which forms a protective layer in potato peel cell walls. We present characteristics of a suberin film produced in the CYCLE project. In summary, this paper presents initial results of some CYCLE studies where food co-streams are utilised for innovative food products and animal feed components. The studies are still in an early stage; however, when linked together, they comprise an interesting example of how cooperation between food and feed science and industry inspires research in the era of bioeconomy. 300

3 MATERIALS AND METHODS Chicken feathers for protein feed (Bioforsk, SINTEF, VTT) Autoclaved dry chicken feathers (7 g, delivered by Norilia, Norway) were cut by scissors and subjected to five hydrolysis treatments with untreated feathers as a control. The treatments compared were pressure boiling, two commercial keratinolytic enzymes, Protex 30L (Genencor International, Inc., Rochester, NY) and Cibenza IDN900 (Novus International, Inc., St. Charles, MO), Cibenza combined with subsequent pressure boiling, and one alkali treatment (Table 1). All treatments were replicated twice. After the hydrolysis step, nitrogen (N) solubility was measured by filtration and analysis of Kjeldahl-N in the residues. Ground residues were subjected to in vitro pepsin digestion (0.2%) and residues were separated by centrifugation and analysed for Kjeldahl-N. N-solubility and in vitro N-digestibility were calculated as the proportion of N in the solution divided by total N. Casein was used as a reference for digestibility analysis. Chicken bones for edible oil (SINTEF) After processing chicken parts to produce deboned meat, bones, cartilages and a small proportion of meat comprises a valuable co-stream for production of oil and protein. Minced material (1500 g) was mixed with water (1500 g, 50 C) and heated to 50 C in a 4000 ml reactor. The enzymatic hydrolysis was started by adding 0.1% of commercial enzyme (dry weight enzyme/raw material) of either Protamex, Corolase PP, or a mixture of Papain and Bromelain. Samples were taken from the reactor after 0, 30, 60 and 120 minutes and inactivated by immediately heating (5 minutes, 90 C). The samples were divided into 50 ml tubes, and centrifuged for 10 minutes. The samples were further separated into four fractions; oil, emulsion, chicken protein hydrolysate and sediments. Vegetable residues for smoothies (Bioforsk, VTT) Aiming at utilising vegetable co-streams as innovative food products, we tested carrot, lettuce, Swedish turnip, red beets and spinach as raw materials for production of smoothies. To optimise colour, three groups of coloured smothies were selected: green leafy smoothie, orange carrot based smoothie and red red-beet based smoothie. We aimed for raw extracts to be consumed fresh or fermented, possibly combining vegetable extracts by fruit extracts in the final smoothies. Mixtures Carrot 1, 2, 3 and Lettuce 1, 2 were evaluated by a local consumer panel. In the carrot mixtures, boiled carrots were mixed with water (Carrot 1), raw carrot juice (Carrot 2) or apple juice (Carrot 3). Leaves of Iceberg lettuce was mixed with apple juice (Lettuce 1), or baby leaf leaves were added to this mixture (Lettuce 2). In a second step, leaves of Iceberg lettuce was mixed with Swedish turnip (Lettuce 3), and to this mixture red beet juice was added (Lettuce 4) to improve colour and sugar content. The final mixture tested in the second step contained boiled red beets, red beet juice and Swedish turnip (Red beet). In the second step, only five persons participated as respondents. In a third step, we tested whether the attractiveness of the smoothies could be increased by adding fruity ingredients. One green mixture (Green fruit) of leafy vegetables and melon (6% spinach, 25% lettuce, 35% piel de sapo melon, 20% apple juice, 4% kiwi, 10% water) and one orange mixture (Orange fruit) of carrot and mango (35% boiled carrots, 25% mango, 12% water melon, 15% apple juice, 13% water) was tested. In all mixtures, root vegetables were used after boiling, or juiced and filtrated to remove fibres. The combined ingredients for each mixture were homogenized by blending (Colin , type BL1616) for 1 minute. Sugar content was measured by refractometer (Brix) and acidity by ph measurements. Viscosity was measured on the prepared smoothie mixtures by a rotation viscometer (Visco tester VT 01/02, Gebryder Haake, Belin, Germany). The extracts will be exposed to fermentation in the next step of this study. Hence, we composed extracts with sugar content > 5% and acidity > ph 5. Extracts that fulfilled these requirements were tested in a sensory preference test by a local consumer panel at Bioforsk with the following alternatives for classification: dislike very much (1), dislike (2), neither like nor dislike (3), like (4) or like very much (5). The panel comprised 11 persons except for one extracts with raw carrot juice (one person being allergic). The test persons were asked to give additional comments to their classification of each sample. A similar test was performed for the vegetable smoothies with fruit supplements, which were tested at a seminar for food scientists in Potsdam, Germany in October 2014 ( Best of the Rest -seminar), with 23 persons commenting the Green and 22 persons the Orange mixture. 301

4 Potato peels for edible film (VTT) By industrial potato peeling, up to half of the raw material potatoes may end up into peels, which are used as feed. Peels are rich in starch and they contain also suberin. Both starch and suberin could serve as components in edible films. We aimed at evaluating film forming properties of a suberin-enriched potato peel fraction and potato peel mass as such, and to compare their properties with a film prepared from pure potato flour. Industrially carborundum peeled Nicola peels were used as raw material. The material was stored as frozen, and before film preparation thawed and wet-milled in a Masuko grinder at 10% solids content using 0.25 mm and 0.2 mm gaps. Potato-based fractions used to prepare the films were: Suberin-enriched peel fraction (0% starch) obtained after starch was gelatinized by heating, hydrolysed with amylase enzymes and removed by filtration. Peel mass as such (46% dry matter (DM) starch) Potato flour (100% DM starch, Finnamyl) Dispersions were prepared of potato fractions by high-pressure homogenization at 2% consistency in a Microfluidics fluidizer M-110EH-30 (4 passes). The operating pressure was 1500 bar. In the film preparation stage, glycerol, which was used as plasticizer, was added at 20% concentration of potato dry weight. The solutions were mixed with SpeedMixer for 5 min, at 1600 rpm under 100% vacuum, cast onto Petri-dishes and dried for two days at ambient conditions. Thickness of the dried films varied between 60 and 90 µm. Rates of water vapor and oxygen transmission as well grease penetration and mechanical properties of the films were determined using standard methods. RESULTS AND DISCUSSION Feather protein Hydrolysis with NaOH gave the highest N solubility, but in vitro digestibility for that treatment could not be analysed due to clogging in the filter paper and low amount of residues. Enzymatic hydrolysis with subsequent pressure boiling resulted in much lower solubility, but the digestibility of the residue was higher than for pressure boiling alone. Enzymatic treatment alone improved solubility slightly, but had no effect on digestibility. A possible interaction between pressure boiling and enzymatic treatment could not be studied in this initial experiment, but is worth further studies. More research is needed to explore possible interactions between enzymatic treatments and pressure boiling. Furthermore, differences in digestibility and amino acid composition of solubilised keratin and residues may be studied in new experiments. Solubility and in vitro pepsin digestibility of N in hydrolysed chicken feathers (n = 2). SD= standard deviation; NA not analysed. Table 1 Treatment Specification N solubility (SD) N digestibility of residue (SD) Pressure boiling 125 C 2 h 2.4 bar 9% (0.0) 41% (2.0) Protex 30L 50 C 2 h + 80 C 1 h 7% (0.2) 11% (0.2) Cibenza IDN C 2 h + 80 C 1 h 13% (0.5) 2% (3.6) Cibenza IDN C 2 h C 20 19% (0.3) 62% (9.2) pressure boiling min 2.4 bar NaOH (1 %) 50 C 2 h + 80 C 1 h 91% (0.8) NA Untreated feathers 20 C 3 h 1% (0.1) 20% (0.4) Lab-grade casein % (1.1) Chicken oil The minced chicken bones (+ cartilage and some meat) consisted of 15.8 ± 0.6% protein, 17.5 ± 2.0% lipids, 5.8 ± 1.9% ash, and 37.7 ± 2.2% water. The oil yields after enzymatic hydrolysis was independent of enzyme type and hydrolysis time ranging from 10.4 ± 0.8 to 12.2 ± 0.1 g oil per 100 g raw material. After 60 minutes of hydrolysis recovery values ranging from 62.2% (Corolase PP) to 71.2% (mixture of Papain and Bromelain) was obtained compared to the total oil content in the rest raw material. The lipid class distribution of the oil fraction was found to consist of mainly triacylglycerol (TAG, %), 302

5 whereas only traces of free fatty acids (FFA), cholesterol (CHL) and phospholipids (PL) were detected. The main component in the oil fraction was the monounsaturated fatty acids (MUFAs), which made up more than 45% of the total amount of fatty acids in the oil. The amount of FFA found in the oil produced by enzymatic hydrolysis was below 0.3%, indicating a high quality raw material. The oxidation status and oxidative stability of the oils will be evaluated. Vegetable smoothie Scores of all tested mixtures are shown in Figure 1. Among the Carrot mixtures, there was a clear preference for Carrot 3, with 60% boiled carrots and 40% apple juice. Lettuce 1 was about as popular as Carrot 1. Lettuce 1 (Iceberg lettuce and apple juice) was characterised as fresh, but had a distinct bitter taste from the iceberg lettuce. Lettuce 2, with baby leaves added, was the least popular. It was characterised as having too much grass taste and being too bitter. When including more vegetable species, Iceberg lettuce mixed with Swedish turnip produced the most popular mixture, Lettuce 3. The turnip supplement caused a surprising, fresh and strong taste which balanced the bitter taste of iceberg lettuce. Addition of red beet juice (Lettuce 4) changed the light green colour extract to a pleasant, purple red colour, and improved sugar content. Boiled and juiced red beet with turnip (Red beet) was not very popular. When including fruits such as melon (Green fruit) and mango (Orange fruit), we found that both mixtures were quite popular (Figure 1), and the orange mixture scored best. For the first time, the highest score (Like very much) was used by some respondents. For the fruity mixtures, the scores dropped drastically when the smoothie temperature increased during serving. 13 answers recorded towards the end of the test when extracts were closer to room temperature had much lower scores than the values shown for the first 22 (23) respondents in Figure 1. Figure 1. Number of scores in a preference test of vegetable mixtures Further studies on vegetable smoothie will include effects of fermentation on taste, concentrations of healthy compounds such as vitamins and physical characteristics like stability and shelf-life. Interesting strains of fungi and bacteria have been developed at VTT, and will be tested with promising mixtures. Edible film from potato peels All potato fractions had good film-forming properties. Potato-based edible films had excellent oxygen barrier properties at low relative humidity (Table 2) and all films were totally impermeable to grease under the conditions tested. Water vapour barrier properties were, however, poor. This is typical to most biopolymer films. Suberin-rich film had higher tensile strength, tensile strain at break (ratio of deformation over initial length) and Young s modulus (a measure of the stiffness) values than the films prepared from peel mass or potato flour. Due to the inhomogeneous structure of the films prepared from unfractionated milled potato peels, their mechanical and barrier properties were not fully competitive with suberin and starch films. Anyhow, both the suberin-enriched fraction and the unfractionated potato peel mass performed promisingly as raw materials 303

6 for (edible) films, but there are challenges in the utilization in practical food applications. For example, better washing of potatoes would be needed if the peelings are to be used for edible film production to ensure hygienic quality of the films. The cheap prize of pure potato starch is also hindering the use of potato co-streams in edible film production. In applications where very low price is needed, e.g. in mulch films, unfractionated potato peel mass may serve as a feasible raw material. This deserves further study. Table 2 The effect of film composition on water vapour permeability, oxygen permeability and tensile properties Potato fraction Water vapor permeability g mm m -2 day -1 Oxygen permeability cc mm m -2 day -1 0% RH, 23 C 80% RH, 23 C Tensile strength MPa Tensile strain at break % Youngs modulus GPa Suberin enriched Peel mass Potato flour CONCLUSIONS The interdisciplinary approach of the CYCLE project, with research institutes from the blue and green sector working closely with food and feed industry, seems to offer a promising arena for development of innovative new food and feed products. If applied to industrial scale, some of these innovations may contribute to a significant reduction in food loss at the processing stage. REFERENCES 1. European Commission Directive 228/98/EC on waste (Waste Framework Directive). Available at 2. Norwegian Ministry of Environment Fra avfall til ressurs. Avfallsstrategi. (From waste to resource. Waste strategy.). Available at 3. Gustavsson, J. C. Cederberg, U. Sonesson, R. van Otterdijk, and A. Meybeck Global food losses and food waste Extent, causes and prevention. Food and Agriculture Organization of the United Nations (FAO), Rome. Available at 4. Hanssen, O.J, and V. Schakenda Nyttbart matsvinn i Norge. Analyser av status og utvikling i matsvinn i Norge Rapport fra ForMat-prosjektet (Efficient uses for food waste in Norway. Analysis of status and developments in food wastage in Norway. Report from ForMat project). Østlandsforskning, Kråkerøy, Norge. Available at 5. Silvennoinen, K., H.-K. Koivupuro, J.-M. Katajajuuri, L. Jalkanen, and A. Reinikainen Food waste volume and composition in Finnish food chain. MTT Report 41, 65 pp. Available at fi/portal/page/portal/mtt/hankkeet/foodspill/food%20waste%20volume%20and%20composition%20 Focus%20on%20Food%20Service%20Sector.pdf 6. Adler, S. et al Utilisation of co-streams in the Norwegian food processing industry. Bioforsk Report Vol. 9 No. 82, Bioforsk, Tingvoll. 7. Tveit, G.M Enzymatic hydrolysis of Chicken Rest Raw Material. M. Sc. thesis. Norwegian University of Science and Technology (NTNU), Trondheim. 304