Building a crunchy biscuit shell on nuts
A crunchy nut is a nut delivering the crunch of a light biscuit in addition to the nut itself. Having the appearance of baked biscuits results in fact from a panning and frying process.
The core is a nut – typically a peanut. Small-size nuts are preferred as coating increases substantially the overall size of the nut.
Different bites can be offered : a hard but shallow coating or a light and thick coating depending of the expansion of the biscuit.
The raw nuts are first coated with a slurry acting as a glue.
This slurry is made of hydrocolloids which have filming and adhesive properties such as:
- Glucose syrup
- Gum Arabic
Then a flour mix is added to build up the biscuit layer. It is composed of:
- Taste enhancers such as glutamate, yeast extract
- Native flours such as rice, maize, or wheat to give body
- Pre-cooked or modified starch to promote the expansion of the biscuit
- After frying, the coated nuts receive a flavouring mix.
How does it work?
A slurry is prepared with water and an hydrocolloid (3 – 10 % dry ingredient depending of the hydrocolloid). The process may vary to provide a different aspect and taste such as with Lebanese-style snacks : the nuts are first roasted then coated with a suspension of starch, the residual heat cooks the starch and extracts the moisture; spices and flavours can be added in the process.
The crunchy coating principle can beapplied in different industries : seed coating is used in the seed processing, a layer of clay with a binder is applied, the scope is to standardize the size of the seed, to protect it, to supply it with nutrients. The coating process runs as follows
Introduction of the nuts in a rotating pan
Application and dispersion of the slurry on the nuts by the rotating motion
Addition and coating of the wet nuts with the flour mix, 1st and 2nd steps are repeated to increase the thickness of the biscuit
Transfer into a fryer with hot oil. Frying completes the coating operation as it cooks the flour and expands the biscuit
Transfer into a pan where various flavours are applied in smaller batches.
The successive liquid and powder applications occur in a batch rotary pan.
The slurry is simply dripped over the nuts and dispersed by the motion.
The flour mix is dosed.
Depending of the size of the batches, the liquid and powder applications are done manually or mechanised with pump and feeder respectively.
As the powder tends to set quickly on the wet surface and form agglomerates, it is recommended to disperse the powder finely and progressively over the nuts.
Frying may be done in batch or continuous fryer.
How do you measure your success?
Key quality features
The product is a combination of features
Peanut is a standard. Small and even size is used. Not split
Crunchy as biscuit, holding firmly to the core
Adheres to the coating
Key quality parameters
Some aspects of this type of coating are critical
Surface tension and viscosity are critical to offer a sticky layer to the powder
Adhesive and expansion properties of the flour mix; flours provided a better expansion when previously cooked or modified
Timely and quantitative control of the liquid and powder addition to prevent excessive humidity, agglomeration, ingredient losses