Patent Application
20160213008
This invention relates to food preservation.
Both quantitative and qualitative food losses occur from harvesting, handling, storage, processing and marketing, to the final delivery of the products to the consumer. The latest published values indicate that, each year, industrialized and developing countries dispose of roughly similar quantities of food. In the developed countries, the losses occur at the levels of retailers and consumers. However, in the under-developed countries, because of poor infrastructure, low levels of technology, and low investment in food production systems, the losses occur at multiple levels including during the production, harvest, post-harvest and processing phases. The post-harvest losses of fruits and vegetables in the developing countries account for almost 50% of the produce.
As estimated by the Perishables Group, Inc., in the years 2005-2006, the average rate of loss for fresh fruit, vegetable, meat, and poultry commodities at the supermarket level, varied from 0.6 percent for sweet corn to 63.6 percent for mustard greens. The study showed that the impact on per capita varied broadly among diverse commodities. Annual supermarket losses in 2006 were 8.4 to 51 percent for fresh fruit with an averaged of 11.4 percent, 9.7 percent for fresh vegetables, and 4.5 percent for fresh meat, poultry, and seafood.
Food and Agricultural Organization (FAO) of the United Nations estimates that 25 to 35 percent of the world food production is lost through natural causes such as pests, microbes, and insects. In the ASEAN countries alone, post-harvest losses are estimated to be 30 percent for cereals, 20 to 40 percent for fruits and vegetables, and up to 50 percent for fish. Some products in Africa show post-harvest losses as high as 50 percent. Rather than increasing production, one of the best actions to the problem of the world hunger, is to preserve what has already been grown . If worldwide post-harvest losses can be minimized, food supply gains removes the necessity to allocate additional resources to further expansion of food cultivation.
Spoilage of food is a process of deterioration that reduces the edibility of food. Ultimately, foods that are partially or completely spoiled become un-edible. Foods that are capable of such spoilage are referred to as being “perishable.” Degradation, loss of color and dissipation of flavor of freshly cut plants is due to a variety of reasons including metal ions, oxidation, enzymatic effects, and growth of microorganisms on food. Autolysis, the process that, over time, is largely responsible for the change in color, texture, and flavor of food, occurs because of effects of enzymes that are naturally present in all plants and animals. The impact of atmospheric oxygen induces changes in color of food and can increase the level of rancidity of food. Finally, infestations (invasions) by insects and rodents account for huge losses in food stocks.
Softening, and discoloration are common changes that occur during ripening and then during the senescence of fruits. Generally, reduction in fruit firmness due to softening is accompanied by an increased expression of cell wall-degrading enzymes. The ripening and senescence of post-harvest fruits is a complex and highly regulated process that involves lipid peroxidation, resulting in the loss of integrity of the plasma membrane. The softening that accompanies ripening enhances fruit damage during shipping and handling processes. This softening plays a major role in determining the cost of fruits because it directly impacts shelf life, resistance to post-harvest diseases and pathogens and on the palatability and consumer acceptability.
Endogenous signaling molecules and hormones such as ethylene, ABA, auxin, IP3, Ca2+, H2O2, and NO are involved in food ripening. An in-evitable result of mitochondrial, chloroplast and plasma membrane-linked electron transport is production of reactive oxygen species (ROS) including H2O2. The reactive nature of ROS, therefore, makes them harmful to all cellular components and cause damage by oxidizing various macromolecules in both plant and mammalian cells. This overproduction of ROS and oxidative damage is a universal event which contributes to the spoilage of post-harvest fruits during storage. Thus, it follows that inhibition of these oxidative damages would prolong the shelf life of post-harvest fruits.
Besides the chemical reactions that spoil food, one of the primary causes of food spoilage is growth of micro-organisms including bacteria and yeast (mold) on food products. The toxic effect from the consumption of spoiled food causes “food poisoning” or “food borne illness.” Some bacteria such as E. coli or Salmonella that grow on food directly threaten the human health. Foods with a high sugar content are susceptible to growth of yeast. Micro-organisms including bacteria and yeast break down food and produce by-products such as acids that lead to changes in taste, texture, aroma, and color that make food less edible. Spoiled, un-cooked, or under-cooked animal meat is typically quite toxic, and its consumption can result in serious illness or death.
Food decay is a process that includes putrefaction, fermentation and rancidity. Putrefaction is one of the seven stages in the decomposition of the body of a dead animal. Fermentation is a metabolic process whereby electrons are ultimately transferred to breakdown molecules of the same nutrients. Rancidification, on the other hand, results from chemical decomposition of fats, oils and other lipids. There are three types of rancidity: ester hydrolytic, oxidative and microbial. Hydrolytic rancidity occurs when fatty acid chains split away by water from the glycerol backbone in triglycerides (fats). Because most fatty acids are odorless and tasteless, this process usually goes un-noticed. However, when rancidification progresses to the release of carboxylic acid from the triglycerides, strong flavors and odors are acquired. In the case of old butter, such flavors and odors are acquired when rancidification leads to a high content of derivatives of butyric acid. Oxidative rancidity is associated primarily with the degradation of un-saturated fat by oxygen. During this process, the double bonds of an un-saturated fatty acid undergo cleavage, releasing volatile aldehydes and ketones. This process can be suppressed by the exclusion of oxygen or by the addition of antioxidants. Microbial rancidity refers to a process by which lipases in the micro-organisms break down the fat in the food. This process can be prevented by sterilization when the food is not perishable by heat. Generally, food decay, as a result of these processes, leads to un-desirable odors and flavors. In processed meats, these flavors are collectively known as warmed over-flavors. Rancidification reduces the nutritional value of the food. Some vitamins are highly sensitive to such degradation processes.
Since the dawn of civilization, mankind has been concerned with the preservation of food. During early civilization, food preservation processes developed slowly and were mainly limited to smoking or curing with salt. With the advent of the industrial revolution and the discovery that food spoilage was due to the activity of living organisms such as bacteria, yeast or molds, the art of preserving food developed rapidly. Due to the health hazards that spoiled food poses, there is a great interest in preserving food and preventing its spoilage. A number of methods have been devised that prevent or slow down this process, expand the shelf-life of food and prolong the duration that food can be consumed. Acidulants are known to prevent microbial degradation by maintaining a relatively low pH environment, but their effectiveness is limited just to temporary conservation.
Present day methodologies for preserving food include sterilization by heat, refrigeration, pickling and the addition of chemical preservatives, Ohmic and dielectric heating, which includes radio frequency (RF) and microwave (MW) heating as well as non-thermal processing. Among other methods are freezing, vacuum sealing (removes oxygen required for growth of micro-organisms), or drying which, by removing water, prevents the growth of micro-organisms. All these techniques prolong food shelf-life.
Among the preservation technologies, chemicals used for food preservation can seep into foods and such substances can not be sufficiently removed for safe consumption by humans. Also, many of the currently used methods are not suitable for all types of perishable foods such as fruits and vegetables. Perishable substances, as described in the present application, also include non-edible perishable substances. Thus, what is needed in preserving food and prevention of growth of micro-organisms is using a method that is safe, cost effective and easy to carry out, particularly for the class of food such as fruits and vegetables, for which, there is no preservation technology available to maintain food freshness.
Many natural compounds can lock food freshness and have antimicrobial properties, however, very few have ever been used to enhance food shelf-life. The new restrictions by the food industry and regulatory agencies in the use of some synthetic food additives, have led to a renewed interest in organic natural compounds and more specifically those that are derived from plants. The current trend of interest in organic food also requires that organic food not to be preserved with chemicals rather with preservatives from natural sources such as those derived from herbs, spices, seasonings or botanical extracts since these foods have been used for centuries by humans without ill effects.
The existing problems in preservation of certain foods that spoil, therefore, require a continuing search for effective, and technically and economically feasible method of food preservation. In addition, the preservation technology must be organic, cheap, safe, should have a good life-span, not subject to rapid degradation, should have broad range of anti-bacterial and anti-fungal activities since different microorganisms grow on different food, should not change the aroma and flavor of food, and must be active from 4 to 25° C.
Thus, as a further advance to this field, a system and process of food perseveration and for prevention of microbial growth is described. The system and process can involve one or more of the following: 1. creating a food preservative from food, or components in food; the term food is used to include all edible substances. 2. combining such components in a manner to lock food freshness, to prevent growth of a broad range of micro-organisms and to increase food shelf-life; 3. devising a method for their capture on a matrix; and 4. delivering the components released from matrix via ultrasonically created micro-droplets. The method that is provided increases food shelf-life and prevents growth of microorganisms on food exposed to volatile substances captured from preservative and subsequently emitted from the micro-droplets.
Other features and associated advantages of the present invention will become apparent with reference to the following detailed description of specific embodiments in connection with the accompanying drawings.
The following drawings form part of the present specification and are included to further demonstrate certain aspects of the present invention. The invention may be better understood by reference to one or more of these drawings in combination with the detailed description of specific embodiments presented herein. In the depicted figures, the number of colonies on Agar plates were counted daily and shown on day 2. The figures shown are a representation of 6-12 set of such cultures. p Values are shown as <0.05 (*), <0.005 (**) or <0.0005.
Specific requirements as necessary for various features, aspects, and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the invention, along with the accompanying drawings in which like numerals represent like components. To this end, food derived components of food with differing anti-microbial properties were captured on a matrix and then allowed their slow release to increase food shelf-life and freshness. Acquiring, retaining and slowly releasing food derived substances with special properties from a matrix by ultrasonically generated micro-droplets requires: 1. a matrix that binds compounds with the desired activity such as antimicrobial property, 2. active compounds with such an activity, 3. binding of the compounds with said property to the matrix with and without the use of solvents and/or carriers, and/or heat, 4. creation of a cartridge that supports the activation and elaboration of active compounds from the said matrix, and 5. delivery of active compounds to a close chamber by a flow of micro-droplets generated by an ultrasonic device.
Many porous and absorbent substrates that exist naturally and their use in food industry is considered safe for human consumption. Among these, diatomaceous earth is a siliceous sedimentary soft rock that easily crumbles into a fine powder comprised of 80 to 90% silica, 2 to 4% alumina and 0.5 to 2% iron oxide. The microscopic matrix of diatomaceous earth makes it a highly effective absorbent for other compounds including gases. Other substances with similar properties exist and include natural or synthetic Zeolites, Celite, Perlite, Silica Gel, Aluminas, Magnesium Aluminate, Aluminosilicates, Magnesium Silicates, Active Carbon, Clays Such As Bentonite, Sepiolite, Attapulgite, Vermiculite, or Mica, and mixtures thereof.
Zeolites are abundant hydrated alkali metal or alkaline earth metal salts of crystalline alumino-silicates with a three-dimensional pore structure that makes them natural adsorbents and desorbents. Clinoptilolites are one the most abundant Zeolites and are used in various applications. The absorbing capability of Zeolites varies and it depends on composition of the Zeolite, the diameter of the particles and the temperature. Chemical composition of Zeolite varies and might include SiO2, Al2O3, Fe2O, CaO, MgO, Na2O, or K2O. For example, a calcined clinoptilolite with an average diameter particle size of 250 μm when subjected to a gas mixture of 1.06% H2S in helium at temperatures of 600° C. can absorb about 0.03 S/g of this gas (Yasyerli et al, Chemical Engineering and Processing 41, 2002, 785-792). Zeolites are shown to capture liquids such as water (H2O), and gases such as N2, O2, CO2 , H2S or SO2. Other separations include noble gases, N2, 02, Freon or formaldehyde. Thus, Zeolites broadly retain both liquids and gases.
To this end, volatile and non-volatile substances in food were methodically tested to decipher their capture on a matrix. The matrix is desirably Zeolite and is used by granulating it into appropriate sizes by a variety of techniques such as an extrusion granulating method, a rotary granulating method, a compression granulating method, or other conventional granulating methods, known to artisans. Depending on the applications, the particle size of Zeolite is not limited and can vary from about several millimeters to 300 mesh or less (50-10 mesh). For improving the mechanical strength and flowability (or fluidity) of the Zeolite particles or to decrease the production cost, other substances such as Bentonite, clay, talc, kaolin, calcium carbonate, diatomaceous earth, and similar substances can be optionally used as a binder, lubricant, or bulk filler. Color or aroma of the product might also be changed by use of natural coloring and aromatic compounds. The present inventor has found that natural or synthetic Zeolite particles can adsorb and retain a relatively large amount of natural food substances including those that are volatile that exist in a variety of food contents with good adsorbability and stability and can efficiently release the adsorbed activity upon addition of an activator including but not limited to cysteine, water or oil. The formulation is suitable for preservation of perishable foods such as fruits and vegetables and for prevention of microbial growth on food or non-food items. The formulation is also suitable for prevention of microbial growth on non-edible perishable or non-perishable substances, surfaces and objects without the requirement of heat.
Because active compounds that bind Zeolite degrade in presence of water, before use, matrix, desirably Zeolite, depending on the level of wetness is dehydrated by subjecting it, to a minimum of 6 hours of a thermal treatment at a temperature of 200° C. to 700° C., desirably 500° C.
Here, active substance(s) in food is defined as those with specific desired property including antimicrobial activity. Active compounds from food and food derived components are those that show a range of specific activities including those that lock food freshness, firmness, aroma, color and taste and prevent growth of microorganisms on food. Foods, spices and herbs have active compounds with such properties. However, foods, spices and herbs are not used as a food preservative for several reasons. These may not be potent in their natural state, may have a limited range of antimicrobial activity, and may show a great variability among plants. Thus, in one respect, food derived formulations with active substances derived from food are devised that show consistent long term antimicrobial property and prolong food shelf-life and freshness.
If active substance(s) is not present in liquid form at ambient temperature and which is not soluble in water, it will be heated or dissolved in a suitable solvent. The temperature can be raised to include the active substances that have a higher melting point. Alternatively, solvents can be used for solubilizing the active substance and the use of solvents for dissolving active compounds in the production of the present food preservative composition are not specifically limited for so long as the active compound does not react with or decompose in the solvent. Desirable solvents are aprotic solvents which are compatible with the active compound(s). Typical examples of such solvents are aromatic hydrocarbons such as benzene, toluene, or xylene; linear or cyclic aliphatic hydrocarbons such as pentane, hexane, heptane, octane, or cyclohexane; halogenated hydrocarbons such as dibromoethane dichloropropane, dichloropropene, chlorobenzene, or dichlorobenzene; or cyclic aliphatic ether such as tetrahydrofuran or dioxane. Once the Zeolite is contacted with active ingredient, it is allowed to dry.
In some instances, when activation of preservative compounds on a matrix requires and activator, such a compound is included in a layer of matrix.
If preservative compounds loaded onto matrix are activated by water, a hygroscopic layer of a matrix is layered over the layers with active compounds to allow for slow activation of preservative compounds.
Active substance(s) is supported on the Zeolite, generally in an amount of 1 part Zeolite and 0.05 to 0.5 parts by weight, desirably 0.08 to 0.2 parts by weight of the active compound(s). Active substance is supported on the zeolite particles by any conventional method such as a dipping method. Generally, active compounds are loaded onto the zeolite by contacting Zeolite with a liquid to allow for their adsorption of active compounds that have a melting point at room temperature onto Zeolite.
4. Assembly of a Cartridge with Food Preserving Property.
A cartridge was devised that includes a free space overlying a layered matrix (
It is also another aspect that formulation with active substances to be retained and slowly released in a sustained manner the desired activity. In accordance with such requirements, there is provided formulations comprising active substances in food with known activity to be released from a matrix by an ultrasonically derived micro-droplet technology. Chester J. Cavallito and colleagues in 1944 discovered that crushed garlic (Allium sativum) exhibits antibacterial and antifungal activity. This activity is attributable to allicin, an organosulfur compound of garlic of the species Alliaceae. Crushing converts alliin to allicin which is unstable and generates other organosulfur compounds such as ajoene, vindyldithiins, S-allylcysteine, and diallyl polydisulfides. Ajoene is an unsaturated disulfide which is formed from reaction of two allicin molecules and which also shows antimicrobial properties.
The ultrasonic device generating micro-droplets that can be set, by a variable control, with the capacity to release from 4 Liters of water, 13 Liters of moisture per day suitable to cover at least 0.7-7 liters of space can be used dependent on the weight (more accurately surface area) of the food content within the chamber (4 Liter Water/13 Liters of moisture/500-5000 grams of food/0.7-7 liters of space). However, it becomes clear that other than delivery of the volatile substances by micro-droplets, such substances can also be delivered by a constant slow flow of air or other gas alone from the cartridge.
A food preservation system comprised of an ultrasonic device, attached to the food preserving cartridge which is connected to a food preservation chamber was devised (
As used herein, the “effective amount” of constituent, compound, composition, preservative, or the like means an amount that exhibits effective antimicrobial activity, preferably wherein the antimicrobial activity is inhibiting growth of, eliminating, and/or otherwise decreasing the presence of microbials such as, for example, yeast, bacteria, mold, and fungus. Also, as used herein, the term “volatile” means that the food product is capable of releasing the active compounds at ambient temperature or by steam distillation at ambient pressure.
In a typical experiment and those represented below, using this system, the ultrasonically driven micro-droplet delivery of preservative substances were set up to assess the antimicrobial effect of our food preserving cartridges on bacterial and fungal cultures. Several different cartridges were developed and tested. Agar plates were streaked with serial dilutions of bacteria and fungi that grow on strawberry, raspberry, tomatoes, pineapple, and bread. These cultures were kept at room temperature within closed chambers that received micro-droplets and the number of colonies on plates were counted daily.
First, liquids were collected by cooling of the micro-droplets before and after passage through a cartridge stacked with layers of matrix with compounds of garlic without and with cysteine. Measurement of H2S level was performed using Free Radical Analyzer (TBR4100 and ISO-H2S-2, World Precision Instruments, Sarasota, FL) followed by the manufacturers' instruction. H2S was detectable only in the liquid that were passed through a cartridge with garlic compounds and cysteine. Cartridges with compounds from garlic extract showed antimicrobial property (
In summary, most preservatives are chemical and they may remain in the food and are consumed by the consumers. In order to overcome such inherent problems in current food preservation, formulations were developed from food that were captured and were then slowly released a desired activity without or with addition of an activator and described the practical method for its use in prolonging food shelf life by preserving food and inhibiting food spoilage.
Advantages of the developed formulation and method of use.
The method offers continuous protection of food, prevents food spoilage or decay, prolongs food shelf life, and prevents growth of micro-organisms. The method combines a series of advantages:
All of the methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While the apparatus and methods of this invention have been described in terms of preferred embodiments, it will be apparent to those of skill in the art that variations may be applied to the methods and in the steps or in the sequence of steps of the method described herein without departing from the perceived concept, spirit and scope of the invention. In addition, modifications may be made to the disclosed apparatus and components may be eliminated or substituted for the components described herein where the same or similar results would be achieved. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope, and concept of the invention as defined by the appended claims.
Thus, specific embodiments of the process of food preservation have been disclosed. It should be apparent, however, to those skilled in the art that many more modifications besides those described are possible without departing from the inventive concepts herein. The inventive subject matter, therefore, is not to be restricted except in the spirit of the appended claims.
This application claims priority to U.S. Provisional Application No. 62/108,522, filed Jan. 27, 2015, which is incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62108522 | Jan 2015 | US |
