US 20050221029A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2005/0221029 A1 Cater et al. (43) Pub. Date: Oct. 6, 2005 (54) OXYGEN SCAVENGING SYSTEM Publication Classi?cation (76) Inventors: Mark W. Cater, Prairie, MN (US); (51) Int. Cl? ..................................................... .. B65D 1/00 Donald A. Grindsta?', Apple Valley, (52) US. Cl. .......................................................... .. 428/341 MN (US) (57) ABSTRACT Correspondence Address: The oxygen scavenging system of the subject invention NAWROCKI, ROONEY & SIVERTSON contemplates a composition, system and appurtenant meth SUITE 401, BROADWAY PLACE EAST odology for substantially eliminating elemental oxygen 3433 BROADWAY STREET NORTHEAST from packaged oxygen sensitive products. The composition MINNEAPOLIS, MN 554133009 or scavenging agent includes an oxidoreductase enZyme, a suitable energy source or substrate for the enZyme, and a (21) Appl. No.: 10/518,292 buffer. The composition binds oxygen When exposed to moisture, thereby reducing the level of oxygen in a closed (22) PCT Filed: Jun. 17, 2003 (e.g., sealed) space such as a food package or the like. More particularly and preferably, the composition includes glu (86) PCT No.: PCT/US03/19029 cose oxidase in an amount of betWeen 1 and 100 activity units (U) per gram, catalase in an amount of betWeen 1 and Related US. Application Data 300 activity units (U) per gram, dextrose in an amount of betWeen about 20 and 99 percent by Weight, and sodium (60) Provisional application No. 60/389,246, ?led on Jun. bicarbonate in an amount of betWeen about 1 and 80 percent 17, 2002. by Weight. US 2005/0221029 A1 Oct. 6, 2005 OXYGEN SCAVENGING SYSTEM or sachets. DraWbacks associated With such approach have included, but are not limited to, careful sealed storage of the [0001] This is a regular application ?led under 35 U.S.C. §111(a) claiming priority under 35 U.S.C. §119(e)(1), of sealed package so as to prevent activation upon exposure to provisional application Ser. No. 60/389,246 having a ?ling oxygen, the expense of such system, and the fact that iron oxide creates heat as it binds oxygen, a less than desirable date of Jun. 17, 2002 and ?led under 35 U.S.C. §111(b). outcome. TECHNICAL FIELD [0008] A further, Widely practiced means of binding oxy [0002] The present invention relates generally to oxygen gen is the use of the enZyme glucose oxidase, in combination scavenging (i.e., targeting and reduction/elimination) for With a suitable glucose source, if necessary. Used alone, oxygen sensitive products, more particularly to a composi glucose oxidase creates or generates peroxide (i.e., hydrogen tion, system, and attendant methodology for removing oxy peroxide is a reaction product). Peroxide may have detri gen from stored oxygen sensitive products such as food, mental effects on the product in the package and its presence pharmaceuticals, etc. may limit the further binding of oxygen by the glucose oxidase. The addition of an appropriate amount of catalase BACKGROUND OF INVENTION enZyme has been used to break doWn the peroxide. This Works acceptably in many systems Where the glucose oxi [0003] The quality and character of products, Whether they dase/catalase mixture is spread over a surface, and the be consumables, intermediates, etc., remain of utmost packaged product acts as a pH buffer, maintaining an accept importance. Furthermore, it is Well knoWn that freshness and able pH range Where the oxygen binding reaction proceeds, shelf life can be key or determinative considerations in one’s hoWever, efforts to use such enZymatic formulations in a selection calculus. Although degradation is a natural phe dispersed or contained form on iron rich products have been nomenon and can in fact be desirable, it more often than not unsuccessful because of discoloration of the product. is a condition sought to be controlled, more particularly eliminated, or at least sloWed doWn, as is almost alWays the [0009] It is believed that the lack of success With such case With perishable goods. enZymatic formulations is most likely due to the oxygen binding reaction being self-limited by the change in pH [0004] Many substances, especially foods, bene?t from Within the bag or sachet (see generally EnZyme Technology, storage in an environment free from, or containing a very Chaplin & Bucke, Cambridge University Press, 1990). As loW level of, free oxygen (O2). Oxygen is knoWn to cause enZymes are amphoteric molecules containing a large num oxidative damage to many products, particularly, but not ber of acid and basic groups, mainly situated on their limited too, fats and oils. When exposed to oxygen many fats surface, the charges on these groups Will vary, according to and oils oxidiZe, With a rancid ?avor imparted to the fat or their acid dissociation constants, With the pH of their envi oil, other qualities and the general character of the oil being ronment. In addition to the reactivity of the catalytically thereby altered. As the oxidation of fats and oils appears to active groups, this directly impacts the total net charge of the be a self-catalytic reaction (i.e., upon initiation, the reaction enZymes, and the distribution of charge on their exterior proceeds relatively quickly, and fully), preventing or retard surfaces. These effects are especially important in the vicin ing the oxidation in the ?rst place is paramount. Further ity of the active sites. Thus, in combination, the variability more, and of equal importance, is the fact that oxygen of the charges With pH (i.e., the charges being a function of supports the groWth of microorganisms Which cause spoil pH) affect the activity, structural stability and solubility of age and discoloration of the product. the enZyme, and have thus been limitations upon this form [0005] Current packaging methods and packaging mate of oxygen scavenging system. rials enable the elimination of much of the oxygen via time [0010] Although the use of a buffer to stabiliZe a liquid consuming vacuum and head space gas ?ushing processes. glucose oxidase system during storage is described in Euro In most cases, some amount of oxygen remains in the pean patent EP0418940, it does not address oxygen removal package. Removal of oxygen from packages of products or buffering of the system during enZyme activity. Similarly, Where gas is trapped Within the product (eg bread or pasta) US. Pat. Nos. 2,765,233 and 5,064,698 teach the addition to is especially difficult. Furthermore, most packaging materi glucose oxidase directly to packaging materials in various als are not impervious to oxygen penetration (i.e., package Ways, namely via encapsulation in polymeric beads. Be this ingress: over time, oxygen leaks through the packaging as it may, there are practical limitations on the amount of material, and into the package). glucose oxidase that can be applied to food Wrappers/ [0006] To retard oxidation, anti-oxidants have been added containers utiliZing heretofore knoWn techniques. No com to foods. For instance, BHA [(1,1-dimethylethyl)-4-meth mercially acceptable oxygen scavenging agent, suitable for oxy phenol] and BHT [2,6-di-tert-butyl-para-cresol] are direct application or subsequently introduced post packag common anti-oxidant food additives. HoWever, BHA is ing, Which virtually eliminates (i.e., binds) oxygen present regarded as moderately toxic by ingestion, and even though and Which further insigni?cantly changes or modi?es the BHT is considered to have loW toxicity, the use in foods of quality or character of the perishable (e.g., does not discolor either of these compounds is limited. While these com the item), has been heretofore disclosed. pounds have contributed greatly to the food industry by reducing the amount of food that must be discarded, some SUMMARY OF THE INVENTION consumers prefer foods Without them. [0011] The subject oxygen scavenging system is generally [0007] In a broader sense, the binding/scavenging of oxy directed to the elimination of oxygen from packaged oxygen gen has typically been accomplished With iron oxide, more sensitive products Where moisture is present of may become particularly, iron oxide packaged Within gas permeable bags present. An oxygen scavenging composition of the subject US 2005/0221029 A1 Oct. 6, 2005 invention includes an enzyme system (e.g., an oxidoreduc Which catalyses the oxidation of [3-D-glucose to D-glucono tase enzyme), a suitable energy source for the enZyme 1,5-lactone, Which spontaneously hydrolyZes, non-enZymi system, and a buffer. The composition, Which enhances the cally, to gluconic acid, using molecular oxygen, With a shelf-life of a packaged product, is suitable for direct appli release of hydrogen peroxide as folloWs: cation to the product of the packaged product With no consumer detectable change in product character. The com position binds oxygen When exposed to moisture, thereby [0016] Hexose oxidase, Which also functions as an effec reducing the level of oxygen in a closed (e.g., sealed) space tive oxygen scavenger and is less speci?c than glucose such as a food package or the like. The system of the subject oxidase, is an enZyme Which in the presence of oxygen is invention contemplates the scavenging composition in com capable of oxidiZing D-glucose, and several other reducing bination With a discrete Water permeable “housing” Within sugars (i.e., substrates) including, but not limited to maltose, Which the composition is contained, or as an integral ele lactose and cellobiose, to their corresponding lactones, With ment or component of a perishable storage container or the subsequent hydrolysis to the respective aldobionic acids like. More speci?c features and advantages Will become (e.g., in the case of D-glucose, gluconic acid). Accordingly, apparent With reference to the DETAILED DESCRIPTION hexose oxidase differs from another oxidoreductases (e.g., OF THE INVENTION, and appended claims.