Snack foods, particularly savory snacks, are extremely popular with consumers. Such snack foods include but are not limited to potato chips, nachos, tortilla chips, corn chips, other extruded snacks, and the like. Such snack foods are typically flavored, or seasoned, with a flowable solid, such as spices and/or seasonings (“seasonings”) by sprinkling the seasonings on the surface of the individual snack items. Examples include potato chips seasoned with salt, barbecue flavoring, sour cream and onion flavoring, vinegar flavoring, etc. Similarly, corn chips and other snack foods are seasoned with various flavorings. The distribution of seasoning is accomplished by sprinkling seasoning on the surface of the products after the products have been cooked and prior to their packaging. The application and distribution of such seasoning greatly affects the product quality. That is, if seasoning is distributed in clumps some chips can be too strongly seasoned while other portions of the same batch of chips, or even portions of the same chip, can be too lightly seasoned, creating a poor quality product. Also, quite importantly, the distribution of seasoning greatly affects the economy of manufacturing. There is a continuing desire to economically measure and uniformly and evenly distribute the seasoning over the snack food during the manufacturing process.
Almost all seasonings vary in their flow properties. The metering of seasonings ensures that a proper amount is applied. Distribution of a seasoning on a product is important to ensure that the seasonings are evenly distributed over the product. Common seasonings in favor with consumers of snack food products can include, for example, barbecue, sour cream and onion, cheese, are sticky, lumpy, and very difficult to dispense. Generally, most seasonings present problems in distribution, not only the above-mentioned seasonings.
Typically, the seasonings are applied with the use of a “flavoring drum” which is a barrel-like container that rotates about an axis that is tilted relative to a horizontal axis. The snack food product to be coated is fed into an elevated open end of the flavoring drum by a speed controlled weigh conveyor. A seasoning feeder, extending horizontally into the drum produces a discharge of seasoning that is applied to the surface of the product located in the drum. As the flavoring drum rotates, the product rotates and is coated as the product mixes with the seasoning within the flavoring drum. Gravity then causes the product to pass to an open discharge end of the flavoring drum and collected on a take-away conveyor.
However, the flavoring drum application method is problematic. The seasoning is typically hygroscopic and tends to agglomerate and plug-up or bridge openings in any associated drum nozzles or slots within the flavoring drum. This can require extensive down time with clean up and sanitation operations to ensure operation of the apparatus. Further, if the product is too dry, the seasoning will not typically adhere to the product surface. If the product is too moist, there can typically be an excess accumulation of seasoning on only portions of the product or in well-defined, discrete regions of the product. Therefore, a device that promotes a consistent, even distribution of a seasoning onto the surface of a product can be highly advantageous.
Another process for the application of seasoning to a product involves the use of a screw conveyor feed system. The typical system includes a screw feeder generally positioned near the center-line and extending into a discharge end of a flavoring drum or a screw feeder positioned above a product passing underneath by conveyor. Seasoning placed in a hopper immediately above the screw feeder flows by gravity into the feed inlet. As the screw feeder turns, the seasoning is enclosed between screw flights and forced along the bottom of the feeder through fine slots or nozzles in order to sprinkle the seasoning on the food product as the food product rotates within the flavoring drum.
However, the screw conveyor system is inefficient and difficult to clean and maintain. The action of the screw feeder packs the seasoning during operations, causing seasoning build-up within the screw feeder and external to the screw feeder housing. Thus, frequent cleaning is required. Additionally, screw feeders can be problematic in that they can add shear stresses to the conveyed seasoning, potentially altering the physical properties of the seasoning. Further, all seasoning build-up is a waste of seasoning that significantly increases the costs associated with processing due to product losses, clean-up and processing down-time.
Other processes can also be used to apply a seasoning to a snack product and are used in the industry. This includes, but is not limited to, belt coaters, roll coaters, brush coaters, blade coaters, electrostatic coaters, and air impingement coaters. All of these methods produce generally unsatisfactory results and have similar high maintenance requirements to maintain an efficient and high throughput.
Examples of flavoring drum applicators are disclosed in U.S. Pat. Nos. 3,606,099; 4,513,918; 4,715,315; 4,755,390; 4,760,778; 5,090,593; 5,386,939; 5,964,146; and 6,113,960. Examples of screw conveyor feed systems are disclosed in U.S. Pat. Nos. 4,493,442; 4,614,162; 4,907,720; 5,287,801; 5,386,939; and 5,846,324. Other coating methods, including belt coaters, roll coaters, brush coaters, blade coaters, electrostatic coaters, and air impingement coaters are disclosed in U.S. Pat. Nos. 3,693,840; 4,936,489; 5,139,801; 5,150,798; 5,353,959; 5,385,086; 5,707,448; 5,855,671; 5,957,332; 6,054,154; and 6,145,708.