Oxygen ethylene scavenger


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Oxygen ethylene scavenger

  1. 1. Oxygen, Ethylene and Carbon dioxide scavenging techniques ABHISHEK KATAGI Ph.D. (Hort.) UHS13PGD57
  2. 2. Introduction Packaging materials have traditionally been chosen to avoid unwanted interactions with food. Food packaging exists to make our lives easier. We need packaging to protect foods from the outside environment, for convenience and to communicate information to consumers about the food inside the package. Migration of packaging materials components into the product, absorption of product components into the packaging material, high permeability to moisture, vapors and gases, as well as to light, are undesired in most of the common packaging systems, such as metal cans, glass bottles and jars and most plastic and composite packages.
  3. 3. New packaging systems are called active, smart or intelligent packaging “Active packaging includes components of packaging systems that are capable of scavenging oxygen; absorbing carbon dioxide/ releasing carbon dioxide, moisture, ethylene and maintaining temperature control and/or compensating for temperature changes”. Maria, Portugal
  4. 4. Active or smart packaging is designed to…. To correct deficiencies that exist in passive packaging To deliberately interact with the product and respond to changes. Product quality, safety and preservation Oxygen and ethylene scavengers, ethanol emitters, carbon dioxide generators and absorbers, Anti-microbial surfaces and time-temperature integrators Optimum conditions to which a food is exposed, while passive packaging is used as an effort to minimize the deleterious effects of a limited number of external variables such oxygen, water and light
  5. 5. Selected examples of active packaging systems Active packaging Oxygen scavengers System mechanisms food Iron based, Metal/acid Nylon MXD6, Metal (e.g. platinum) catalyst Ascorbate/metallic salts Enzyme based Applications Bread, cakes, cooked rice, biscuits, pizza, pasta, cheese, cured meats and fish, coffee, snack foods, dried foods and beverages Carbon dioxide Iron oxide/calcium hydroxide scavengers/emitters Ferrous carbonate/metal halide Calcium oxide/activated charcoal Ascorbate/sodium bicarbonate Coffee, fresh meats and fish, nuts and other snack food products and sponge cakes Ethylene scavengers Potassium permanganate Activated carbon Activated clays/zeolites Fruit, vegetables and other horticultural products Preservative releasers Organic acids Silver zeolite Spice and herb extracts BHA/BHT antioxidants Vitamin E antioxidant Chlorine dioxide/sulphur dioxide Cereals, meats, fish, bread, cheese, snack foods, fruit and vegetables
  6. 6. Cont.. Ethanol emitters Encapsulated ethanol Pizza crusts, cakes, bread, biscuits, fish and bakery products Moisture absorbers PVA blanket Activated clays and minerals Silica gel Fish, meats, poultry, snack foods, cereals, dried foods, sandwiches, fruit and vegetables Flavour/odour absorbers Cellulose triacetate, Acetylated paper Citric acid, Ferrous salt/ascorbate Activated carbon/clays/zeolites Fruit juices, fried snack foods, fish, cereals, poultry, dairy products and fruit Temperature control packaging Non-woven plastics, Double-walled containers, Hydrofluorocarbon gas Quicklime/water, Ammonium nitrate/water, Calcium chloride/water Super corroding alloys/salt water Potassium permanganate/glycerine Ready meals, meats, fish, poultry and beverages Maria, Portugal
  7. 7. A scavenger in chemistry is a chemical substance added to a mixture in order to remove or inactivate impurities or unwanted reaction products Oxygen scavengers (also referred to as oxygen absorbers) -- food product quality by decreasing food metabolism, reducing oxidative rancidity, inhibiting undesirable oxidation of labile pigments and vitamins, controlling enzymic discoloration and inhibiting the growth of aerobic microorganisms. Small sachets or self adhesive labels that are placed inside modified atmosphere packs to help extend product life (notably cooked meats) and help improve product appearance. The reduction of oxygen inhibits aerobic organisms, especially mold, and prevents oxidative rancidity. Maria, Portugal
  8. 8. Table : Selected oxygen scavenger systems Maria, Portugal
  9. 9. Cont…
  10. 10. Principles Easily oxidizable --- remove O2 by means of a chemical reaction In sachets made of a material highly permeable to air but it can also be included in bottle closures or in the plastic film matrix Use of scavengers led to faster reduction and to lower levels of residual oxygen, as compared to nitrogen flushing. These chemical systems often react with water supplied by the food to produce a reactive hydrated metallic reducing agent that scavenges oxygen within the food package and irreversibly converts it to a stable oxide. The most common substances used are iron powder and ascorbic acid.
  11. 11. O2 scavenger several requirements:- Be safe and not produce toxic substances or odors - Be handled easily - Be compact in size and absorb a large amount of oxygen - Have an appropriate rate of oxygen absorption, and - Be economic. The scavengers may be of self-reaction type or moisture dependent
  12. 12. The oxidation mechanism of iron powder can be expressed as follows: Scavengers also differ in the reaction speed: from immediate action (0.5 to 1 day) to slow action (4 to 6 days); on the application :: particularly the moisture content of the food; and on the function :: i.e., oxygen scavenging only or dual function, such as absorbing or generating carbon dioxide, besides removing the oxygen. oxygen scavengers --- capable of reducing oxygen levels to less than 0.01% which is much lower that the typical 0.3–3.0% residual oxygen levels achievable by modified atmosphere packaging (MAP).
  13. 13. The iron powder is separated from the food by keeping it in a small, highly oxygen permeable sachet that is labelled ‘Do not eat’ and includes a diagram illustrating this warning. The main advantage of using such oxygen scavengers is that they are capable of reducing oxygen levels to less than 0.01% Oxygen scavengers can be used alone or in combination with MAP Non-metallic scavengers include those that use organic reducing agents such as ascorbic acid, ascorbate salts or catechol. Enzymic oxygen scavenger systems using either glucose oxidase or ethanol oxidase, Day, USA
  14. 14. Selection of the oxygen scavenger, considerations :The nature of the food, such as size, shape and weight The moisture content and water activity The initial (residual) oxygen content in the package head-space The amount of oxygen dissolved in the product The maximum allowable oxygen intake to end product shelf-life The packaging material permeability to oxygen.
  15. 15. EVOH as an oxygen barrier layer for prolonging the shelf-life of foods plastic packaging systems (containing ethylene-vinyl alcohol copolymer (EVOH)
  16. 16. Oxygen absorber----Pizza
  17. 17. Table. Properties and types of FreshMax TM and FreshPaxTM O2 scavengers.
  18. 18. Fig . AgelessTM formats available: sachet, pressure-sensitive label and card. Oxygen scavenger Label FreshPaxTM and FreshMaxTM
  19. 19. Figure. Crown oxygen scavenger from Darex (W.R.Grace).
  20. 20. • Oxygen scavenging sachets ---- disadvantage ---- accidental ingestion ----hampered their commercial success, particularly in North America and Europe. Soln: Development of oxygen scavenging adhesive labels (increased safety) Uses : Sliced cooked and cured meat and poultry products, which are particularly sensitive to deleterious light and oxygen-induced colour changes Coffee, pizzas, speciality bakery goods and dried food ingredients (Hirst, 1998). Cakes, breads, biscuits, croissants, fresh pastas, cured fish, tea, powdered milk, dried egg, spices, herbs, confectionery and snack food. (Day, 2001). Self Adhesive Oxygen Absorbing labels
  21. 21. Nuts and many high-oil content, processed foods have saturated fats which can oxidize, creating an off-flavor and texture issues. Maintaining the fresh, out-of-the-oven consumer appeal and texture can be achieved during extended shelf life using MultisorbÕs innovative active packaging technology. Powders, such as baby formulas and geriatric meal replacements, have traditionally relied on unhealthy trans-fats to maintain shelf life. Active packaging technology allows formula producers to maintain a desired shelf life while eliminating the use of trans-fats. powder powder
  22. 22. Organic foods made without preservatives And ---- loss of flavor, color, moisture and nutrients. ---extend shelf life and lengthen the distribution chain of goods without additives or preservatives, thus maintaining organic product integrity. FreshCardTM FreshMax¨ FreshPax
  23. 23. “Reduced Oxygen Packaging” means: (i) The reduction of the amount of oxygen in a package by removing oxygen; displacing oxygen and replacing it with another gas or combination of gases; or otherwise controlling the oxygen content to a level below that normally found in the surrounding, 21% oxygen atmosphere (ii) Food for which the hazards of Clostridium botulinum and Listeria monocytogenes require control in the final packaged form
  24. 24. Ethylene Principles scavengers Ethylene is a plant hormone that accelerates the respiration rate and subsequent senescence of horticultural products such as fruit, vegetables and flowers. Many of the effects of ethylene are necessary (e.g. induction of flowering in pineapples and colour development in citrus fruits, bananas and tomatoes) but in most horticultural situations it is desirable to remove ethylene or to suppress its effects. Ethylene is a very reactive compound that can be altered in many ways, such as chemical cleavage and modification, absorption, adsorption, etc. This creates a diversity of opportunities for commercial applications for the removal of ethylene
  25. 25. There are a number of ethylene removal technologies available: – Catalysts. Often based on platinum/alumina, these operate at elevated temperature (> 200ºC) and catalytically oxidise ethylene to carbon dioxide and water. --- Use of photocatalytic oxidation of ethylene using titanium dioxide, which can occur at room temperature -- Stoichiometric oxidising agents. Mostly based on potassium permanganate, which again oxidises ethylene and is itself reduced. Sorbents: Sorption of the ethylene and are often based on high surface area materials, including activated carbon, clays and zeolites.
  26. 26. Ethylene Blocking Technologies 1-Methylcyclopropene (1-MCP). 1-MCP is the most widely used commercial volatile ethylene inhibitor, which blocks ethylene binding sites. Silver thiosulfate (STS). The use of this material is largely restricted to cut flowers and it is sold commercially under the trade name Chrysal AVB®. Aminoethoxyvinylglycine (AVG). This material is sold commercially as ReTain® and acts as a plant growth regulator by blocking the production of ethylene in the plant tissue
  27. 27. Table : Selected ethylene scavenger systems
  28. 28. Commercial examples Potassium permanganate-based scavengers:KMnO4 are available in sachets for packages or blankets for storage chambers--- not incorporated into food Immobilized in-- inert substrate such as alumina or silica gel-- 4 – 6%. The performance and useful life of the scavengers depend on the substrate surface area and the content in permanganate. Potassium permanganate oxidises ethylene to acetate and ethanol and in the process changes colour from purple to brown, and hence indicates its remaining ethylene scavenging capacity
  29. 29. Ethylene Control, Inc. (USA) ---scavenging capacities: 5g, 9g and 28g, respectively --- boxes up to 10 lb, 30 lb and 50 lb of produce (one single sachet per box is considered enough for protection). Air Repair from DeltaTrak, Inc. -- alumina beads impregnated with potassium permanganate --- packets of 5g and 8g for boxes, tubes of 5 in. for display cases and small coolers and 20 in tubes for walk-in coolers, as well as blankets and bulk beads available by the pound. Figure. Sachet of ethylene scavenger from Ethylene Control, Inc.
  30. 30. Activated carbon-based scavengers Ethylene can be removed by a system using various metal catalysts on activated carbon. This type of scavenger is more popular in Japan. Examples:-- SendoMate from Mitsubishi, which is based on a palladium catalyst -- Hatofresh System from Honshu Paper, which is based on activated carbon impregnated with bromine-type inorganic chemicals -- Neupalon from Sekisui Jushi (Japan)
  31. 31. Activated earth-based scavengers --Finely dispersed clay embedded in polyethylene films or bags that are used for fresh produce----clays, pumice, zeolites, coral, ceramics, sand, etc. -- Adsorb the ethylene, they also open pores within the plastic layer---ethylene will diffuse much more rapidly through open pore spaces within the plastic than through the plastic itself, it should be expected that ethylene will diffuse out of these bags faster than through pure polyethylene bags. Commercial examples: Orega bag (Korea), Evert-Fresh Bags made of oya clay dispersed within polyethylene film matrix (USA), FH from Thermo Co., and many others.
  32. 32. Dual-action ethylene scavenger and moisture absorber ( Japan, Sekisui Jushi Ltd.) --- Neupalon™ sachets --- activated carbon, a metal catalyst and silica gel and are capable of scavenging ethylene as well as acting as a moisture absorber --- Equilibrium modified atmosphere is likely to develop within these bags compared with common polyethylene bags, especially if the produce has a high respiration rate. [Improve produce shelf life and reduce headspace ethylene independently of any ethylene absorption or adsorption]
  33. 33. Carbon dioxide generators and absorbers Principles Carbon dioxide generators --- packaging for fresh produce where an increased concentration of CO2, combined with decreased O2 concentration, reduces the respiration rate thus increasing the product shelf-life -- Emitters is in the packaging of meat products where a high level of CO 2 may inhibit microbial growth. --Commercial solutions commonly used are the incorporation of a one-way valve and more recently, the inclusion of a CO 2 absorbing sachet.
  34. 34.  Removal of CO2 is needed, as in the case of roasted ground coffee. Substantial quantities of CO2 are released on grinding coffee, which must be removed from the package to avoid pressure build up and bursting, in the case of flexible pouches.  A mixture of calcium oxide and activated charcoal -- coffee pouches to scavenge carbon dioxide but dual-action oxygen and carbon dioxide scavenger sachets and labels are more common and are commercially used for canned and foil pouched coffees in Japan and the USA (Day, 2003; Rooney, 1995)  Dual-action sachets and labels typically contain iron powder for scavenging oxygen and calcium hydroxide, which scavenges carbon dioxide when it is converted to calcium carbonate under sufficiently high humidity conditions
  35. 35. Commercial examples R R Examples of generators or emitters include: Ageless G, Toppan C and Vitalon GMA, although most of the carbon- and earth-activated based ethylene absorbers also claim carbon dioxide absorption capacity. Ageless G is a self-working type, based on ascorbic acid oxidation mechanism, and absorbs oxygen and generates an equal volume of CO 2. R Examples of absorbers include Ageless E, which also functions as oxygen scavenger. It is based on powdered iron and calcium hydroxide end
  36. 36. Thank you