Page 44 - FoodFocusThailand No.222 September 2024

SMART PRODUCTION

Extrusion Process in Snack Production For snack products produced through the extrusion process,
The extrusion process is a method with the potential for particularly instant puffed snacks, there is an advantage in that
industrial-scale production, utilizing machinery known as an the products can puff without frying, resulting in a low oil
extruder. The extruder combines several techniques, including content in the snack. Typically, vegetable oil or fat is used to
mixing, kneading, shearing, heating, and forming. The primary adjust the texture, preventing it from being too hard, and it is
components of the extruder and their functions include the generally used at less than 2% of the raw material weight.
hopper that receives and feeds the raw materials into the However, most of these products undergo flavor coating, which
barrel, which is a cylinder composed of several segments can be done in two ways: wet coating, which involves mixing
called “heads,” each of which can be temperature controlled. the flavor coating, usually composed of sugar and syrup, onto
Inside the barrel, a screw with various shapes is used to knead the snack and then baking it to dry, and dry coating, which
and mix the raw materials into a homogenous mixture. The involves spraying vegetable oil onto the snack’s surface, then
last component is the die, which is located at the end of the sprinkling and mixing the seasoning powder evenly, and drying
barrel. It is a small opening that allows the heated materials it. The vegetable oil used in the dry coating may account for
to be pushed out to the external environment, defining the up to 10% of the snack’s weight. Moreover, the texture of snacks
product’s shape. The die may also have attached blades to from the extrusion process depends on the conditions
cut the product to the desired size immediately or to draw it controlling the machinery, such as the barrel temperature,
out for a more elongated shape before cutting. screw rotation speed, moisture content, and specific properties
For the production of puffed snacks or breakfast cereals, of the raw materials, like rice and corn. Additionally, small
the raw materials—typically grains like rice and corn—are amounts of food additives may be used to improve the snack’s
mixed until homogenous before being fed into the hopper. The texture, such as using calcium carbonate (CaCO ) to create
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screw then conveys, kneads, and compresses the food while small, uniform pores or emulsifiers to reduce the problem of
the barrel heats the materials to the appropriate temperature— the product sticking to the roof of the mouth. Another advantage
often between 150 and 200 ºC in just a few seconds. This of puffed snacks and third-generation snacks produced by the
process causes structural changes, such as starch gelatinization extrusion process is the relatively high retention of vitamins
and protein denaturation. As the cooked dough passes through or essential substances, such as anthocyanins, due to the
the die, which is an opening to the external environment, the short processing time, which helps minimize the loss of these
pressure rapidly decreases, causing steam evaporation substances.
immediately that inflates the food structure. When the product Furthermore, manufacturers and researchers are continually
reaches atmospheric pressure and room temperature, it working to develop snack products that offer a variety of
maintains its shape with a porous, crispy, and light texture. additional health benefits. This effort aims to challenge and
Additionally, the extrusion process can also be used to shift consumer perceptions that these snacks are merely
produce third-generation snacks. The production conditions starchy, non-beneficial, and high in monosodium glutamate.
are adjusted to prevent significant pressure differences By incorporating and enhancing various ingredients, such as
between the inside and outside of the barrel, as these products using natural ingredients with unique characteristics—like
are meant to be cooked but not puffed. The products will only producing snacks from riceberry, which is rich in anthocyanins,
puff and crisp when reheated by frying or baking at high or making high-protein snacks from mung beans supplemented
temperatures. The main ingredients often used for these with spirulina. Both of these products were developed by the
products are starches from tuberous plants, such as cassava Institute of Food Research and Product Development,
and potato starch. Kasetsart University. Additionally, plant or animal proteins can
be added to snacks, and vegetable or fruit powders can be
Development of Healthy Snack Products through included as sources of vitamins and dietary fiber.
the Extrusion Process However, it is important to remember that snack products
In developing healthy food products, manufacturers must first are merely supplementary foods consumed between meals,
understand the needs of their target consumers, as these with carbohydrates as the primary ingredient. Additionally,
needs can vary widely. For example, some consumers may flavorings are added to enhance taste and appeal. Therefore,
seek high-protein foods, essential nutrients foods, low-calorie limiting and controlling snack consumption is advisable, as well
foods, low-fat foods, sugar-free foods, and low-sodium foods. as ensuring a balanced diet by consuming a variety of other
Thus, the development of healthy foods can be categorized foods for complete nutrition.
into two approaches: 1. Enhancing or Preserving desirable
attributes such as foods that increase protein, vitamins, dietary
fiber, and antioxidants, and 2. Reducing or Eliminating
undesirable components such as foods that are fat-free,
sugar-free, low in sodium, and free from preservatives, etc. More Information Service Info C005
Each type of food can be developed to incorporate both
attributes simultaneously.

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