Grace Food Processing & Packaging Machinery offer wide range of snack seasoning and coating system for different kind off baked and fried snack. Consumers rate snacks by taste, feel and sight—it’s an instant organoleptic experience. So the correct application of snack seasoning is crucial, especially since it is a product’s main carrier of flavor. The right automated seasoning system can ensure that free-flowing, spray-dried, and encapsulated flavours are applied uniformly. Since snacks are usually still hot when seasoning is applied, special care is needed to ensure that volatile flavours do not flash off.
Seasoning System Types
The objective with flavouring snacks is to apply a uniform and consistent seasoning layer to all sides of the Snack product. This ensures that the snack always looks and tastes the same.
a) Conveyor-type dispenser
The most basic method in practise today is the conveyor-based system; a common use is the application of salt. Unless the product is turned over, only one side is coated. These systems are often equipped with a variable speed drive allowing for different application rates across the width of the entire roll.
b) Tumble drum (with Scarf Feeder & Spray Nozzle)
A more advanced application is the tumble drum and seasoning dispenser. Here the aim is to create a tumbling action by ‘rolling the bed’. Seasoning is applied uniformly at a predetermined rate. Product travels forward through the angled seasoning drum which is sloped downwards from the entrance to the exit. Product exposure or ‘dwell-time’ depends on drum design, rotation rate and angle.
We offers the Revolution Seasoning System which combines a removable seasoning drum and a horizontal-motion conveyor in a single machine. The forward motion of the conveyor pushes the product through the rotating drum as seasoning is applied, eliminating the requirement of a gradual slope. Dwell time is adjusted by manipulating the speed of the conveyor.
Application methods
The most common seasoning application of is the use of a dry powder applied through a flighted tumbling drum, run at an angle.
a) Dry Seasoning (single-stage)
This application method is suitable for dry seasoning powders and only where sufficient surface moisture is present (e.g. frying oil) to ensure adherence. Examples of product with sufficient unabsorbed surface oil would be potato and corn chips.
The seasoning is usually dispensed from the loading hopper to the tumble drum via an auger, open spiral, vibratory (scarf) plate or a horizontal-motion conveying action. One of the objectives is to try and achieve the largest application area possible. Traditional systems had a single drop point off the open end of the auger tube. Later designs called Picollo tubes featured multiple drops across the length of the distribution tube.
Electrostatic enhancers work by charging seasoning particles to improve adherence onto the snack surface. Depending on the system design, fine particles in the air can be a major disadvantage. Meanwhile, the latest designs aim to create a ‘curtain’ of seasoning, increasing the seasoning-exposure rate of each product piece, before exiting the system.
A further improvement is application rate control is known as loss-in-weight systems, where the aim is to adjust seasoning feed based on product feed, to eliminate seasoning waste. The earlier systems were based on placing the feeder on load cells. The latest designs use a combination of photo and ultrasonic sensors. The signal from the sensing device is compared to a set point, and automatically adjusts seasoning rates to compensate for product fluctuations, matching the target seasoning rate.
Dry-application rates are typically in the order of 6-8 percent of product weight, or are expressed as a percentage of salt content.
b) Wet & Dry Seasoning (two-stage)
This method is typically used when there is not enough surface moisture on the product to ensure that the seasoning sticks. This is the case for tortilla chips, baked and fried extruded snacks, nuts, popcorn and pretzels.
A liquid phase—usually oil—is applied as product enters the tumble drum, to act as an adhesive for the dry seasoning. As is the case with dry seasoning, the aim is to get the widest possible spread of oil and powder. The oil application is often achieved through a manifold feeding a number of spray nozzles. Maintaining a consistent spray pattern is achieved in several ways; however, the latest designs use multiple nozzles, each with its own air supply. The liquid and dry zones are typically separated in the tumbling drum, allowing for complete control in setup, and to prevent contamination. In certain applications these stages can be separated with two tumble drums operating in-line.
Two-stage seasoning rates are typically 3-10 percent oil, followed by 6-8 percent dry seasoning.
c) Slurry Seasoning (Oil and Seasoning Powder Mix)
This application method was designed for products with a very dry surface (e.g. baked extruded snacks, popcorn and pretzels).
This application method uses mixtures of liquid and undissolved solids. Nozzles in the slurry systems typically have a low-pressure air supply to ensure uniform and dispersion. However blockages can occur, depending on the solids used—especially if spraying particles of irregular size, or if the slurry viscosity changes as the holding tank runs empty. It is important to maintain these undissolved solids in suspension, so the design of tanks and the agitator position is extremely important. Blocked nozzles result in pressure drops over the supply manifold, altering spray patterns of any remaining nozzles. Self-cleaning nozzles are featured on better-designed systems.
In the case of slurry, seasoning is added to the oil at levels up to 40 percent and kept in agitation to prevent separation. The slurry is then applied to the snack at levels of 10-20 percent.
System design
The design of a seasoning system, more specifically the tumble drum, is critical. The flight pattern, frequency of flights, drum diameter, rotation speed, angle and dwell or residence time is designed for specific products and throughput ranges. Drums are typically fabricated out of stainless steel, with folded and not welded flights, to ensure a smooth surface and reduce risk of seasoning build-up.