Invented by Josip Simunovic, Kenneth R. Swartzel, Van-Den Truong, Gary Dean Cartwright, Kandiyan Puthalath Sandeep, David L. Parrott, Pablo Coronel, Microwave Techniques LLC, North Carolina State University, US Department of Agriculture USDA
The Microwave Techniques LLC, North Carolina State University, US Department of Agriculture USDA invention works as followsMethods, apparatuses, and foods and other materials for thermally treating flowable material using electromagnetic radiation. Methods and apparatuses for continuous flow thermal treatment biomaterials are also provided.
Background for Methods of thermal treatment of food and other biomaterials, and the products that are obtained therefrom
Food must be treated in order to sell to the public. This is to reduce the risk of microbial growth between harvest and purchase. There are many commercially available methods to accomplish this. The most common is heating the food to the appropriate temperature for the required time to kill any microorganisms or spores that might grow and germinate at the stored temperature. Pasteurization is used to preserve milk for longer periods of time. This reduces the amount of bacteria in milk.
For example, sweet potato utilization in the food industry often involves the processing of roots into purees that can then be frozen or canned to ensure year-round availability. Sweet potato puree (SPP), can be used in a variety of products including baby food, desserts, cakes, pies and breads (Truong, 1992; Truong, et al. 1995; Woolfe 1992).
There is a long-standing and ongoing need for efficient methods to heat treat food and biomaterials. This and other art needs are addressed by the currently disclosed subject matter.
This Summary contains a number of embodiments of the subject matter currently disclosed. In many cases, it also lists variations and permutations. This summary is only a sample of many and varied embodiments. It is also possible to mention one or more of the representative features of a particular embodiment. This embodiment can exist without or with the feature(s) mentioned. Likewise, these features can be applied in other embodiments of the currently disclosed subject matter. This Summary does not include or suggest all combinations of these features to avoid repetition.
The presently disclosed subject matter consists of processes that thermally treat a flowable materials while continuously passing the flowable material through a thermal treatment device. The process may include: (a) continuously passing a flowable substance through a conduit where at least one portion is transparent to electromagnetic radio radiation; (b), heating the flowable matter by exposing at least one portion of conduit to electromagnetic radiation; and finally (c) mixing the flowable materials within the conduit to achieve thermal equalization in at most one portion of it. Some embodiments allow for constant flow rates. Some embodiments allow for constant heating power input and constant temperature at the heating exit to the flowing biomaterial.
In some embodiments, flowable materials are selected based on at minimum one of the following properties: rheological or dielectric. The flowable material may be a biomaterial in some instances. The biomaterial may be a food biomaterial in some embodiments. Some embodiments select the food biomaterial based on at minimum one of the following properties: rheological or dielectric.
In some embodiments, heating causes a bulk temperature increase rate of at least 1 degree Fahrenheit per minute or 0.5 degrees Celsius each second in flowable material. One or more additional heating steps may be employed in some embodiments. One or more additional heating steps may be used in some embodiments to increase the bulk temperature of the flowable material by at least one degree Fahrenheit per minute or 0.5 degrees Celsius per minute. Heating can be done with the flowable material at a temperature higher than the maximum temperature of the material.
Some embodiments of the subject matter disclosed herein, the mixing precedes or accompanies the heating. Mixing can be achieved by changing the cross-sectional geometry or flow. Mixing can be done passively, active, or both. Mixing can be achieved using any combination passive, active, or both active and passive mixing devices that increase heat exchange between regions of flowable materials with higher temperatures and those at lower temperatures. This would not happen without the mixing devices. Mixing provides at least 10% less temperature distribution variability (standard deviation), across the flowable materials than the temperature distribution variability across the flowable materials in the absence the mixing devices. The process may include placing the mixing device at one or more points in the group that includes one or two points of entry, one, or more points within, one, or more exits and combinations thereof of the conduit exposed to electromagnetic radiation.
Some embodiments of the subject matter disclosed herein do not heat the flowable biomaterial. This provides a heater section that isn’t burned on biomaterials, and enables the process to run at a faster rate than indirect heating systems.
In some embodiments the heating and mixing provide sufficient temperature to allow for sterilization or pasteurization of the flowable materials.
In some embodiments, packaging the flowable material is done for refrigerated storage. Some embodiments further include aseptically packaging flowable material.
In some embodiments, the contact surface of the flowable material is sterilized before the introduction of the flowable biological material. Some embodiments involve heating the flowable material for a predetermined time and then cooling it. Finally, the flowable material is sealed in a sterilized container. Some embodiments involve the filling of the flowable material at a predetermined temperature into a nonsterile package, under either atmospheric or increased pressure conditions. This allows for simultaneous sterilization of all surfaces that come in contact with the material. The package is then hermetically sealed.
The currently disclosed subject matter also includes a product that is produced using the disclosed processes.
The subject matter presently disclosed also provides a commercially safe food or biomaterial having one or several quality attributes that are preserved to a greater degree than a reference food, or biomaterial that has been sterilized using thermal treatment methods that involve contacting the reference food with a surface whose temperature remains constant above a predetermined temperature for the food. Some embodiments do not contain any additional acid.
The subject matter disclosed herein also includes a thermally-treated food or biomaterial with a quality profile that substantially matches the quality profile of untreated food or biomaterial of the identical type. The thermally treated food/biomaterial is shelf stable and commercially sterile. The quality attribute may be selected from the following categories: nutrient content and color, texture, flavor, and general appearance. Some embodiments include hermetically packaging the food or biomaterial. Some embodiments use sweet potato or white (e.g. Irish) potatoes as the food or biomaterial.
The subject matter disclosed herein also includes a thermally-treated food or biomaterial with a quality profile that substantially matches that of untreated food or biomaterial of the identical type; (iii). The food or biomaterial is sweet potato, white, or Irish potato; and (iii). the amount of food in the package exceeds that which can be accommodated in Type 10 cans. Some embodiments do not contain any additional acid components.Click here to view the patent on Google Patents.