The technology behind predusting of products

Most products are predusted for adhesion purposes, making a coating stick on a product.

The best example is a schnitzel, during frying the meat shrinks and the batter and crumb coating comes free from the meat, by predusting it creates a sticky glue between the meat and the coating.

How does it work:

The predust (a mix of plain flour and/or starch) has a side which loves oil or fat and the other side wants to stick to water. The meat is the greasy side and the batter and crumb the water side.
During coating it is very important to have a minimum of predust on the product, just enough to cover it!
Too much predust will make the batter run of, a spot without coating will be visable on the product
Not a full coverage and the coating will not stick during cooking

The product

Which type of product are we dealing with.

A whole muscle product. Cut from one piece of meat or fish, so mainly hand cut in one thickness.
This has to be covered with a thin even layer of predust to obtain adhesion to the product.
Solution flatbed preduster

An irregular product, totally uneven in thickness and irregular in shape, fe. a piece of broccoli
To get into the cavities there is labour needed, you have to toss the product a couple times through a bed of flour to get it evenly coated, with again a minimum of flour.
Solution drumbreader

A formed product, any shape needs to be predusted all around in an even way.
Again a minimum layer of predust is needed for the right adhesion. Fe. a formed schnitzel
Solution flatbed preduster

Chicken parts, to get the right coverage the chicken parts have to be tossed a couple of times in a bed of predust, to get evenly covered. Fe. Southern fried chicken
Solution drumbreader

Predust types

There are many different types of predust but you could put them in 3 groups:

1. Predusts for adhesion.
This type of predust mainly consists of flour, the other main ingrediënt is starch or modified starch. For fish salt is very important, specially with defrosted fish, if the fish is only surface defrosted the salt is needed for the coating to set before freezing back into solid.
Modified starches, the are so many types, heat treated, chemical etc etc.

2. Predust for flavouring.
It speaks for itself, add the flavor on the outside of your product together with flour or starch for adhesion purposes

3. Predust with an effect.
Think of southern fried chicken, in this case bicarbonate is added to the predust, in the several coating steps a cocoon is made around the product, the bicarb will create micro bubbles during the frying proces. To this type of predust most of the times flavor is added.

Coating steps:

There are many possibilities for coating products, these steps are very important step by step, to have a optimal result all variations should be minimized, maybe a good idee for you, the Wizz-cup for wizz-cosity in you batter machine, the cooking proces behind it is delicate, fully fried or combinations.

Cooking:

The traditional way was to pre fry only or a fully fry (core 72ºC+), the step after that was a pre-fry and fully cook in an oven with temperature and humidity control.
An even more effective way is the innovative cooking method, this also needs a lot less energy.
Predust - steamcook - coating - short fry - freezing
For this system a special predust is needed which even picks up moisture during steaming, is than coated and flash fried to set the coating, the yield is a lot higher than traditional.
The innovative cooking method needs some extra requirement to be a succes, special predust, cooling on batter equipment.

FYI bone-in chicken has to be fully cooked, core temperature 84ºC+, check by breaking the bone, no blood it must be a brown marrow.

Manfred Snijders
Food/Proces technologist

If you have any technology or proces related questions: