We always enjoy snack foods even the fried ones and their manufacture should not be a mystery to anyone involved in their production. Perhaps the most interesting development is the use of pellets and how they are processed. Pellets for frying actually led to a new processing system called the pellet drying system.
Most pellet snacks are produced in a great range of sizes and colours with different textures and flavour. They have by all accounts a much more brittle texture, slightly crispy and more solid crunch.
The business is extremely large. According to global marketing reports, the market size was USD 6602 million in 2022 and set to rise to 8068 million by 2028. The CAGR was predicted to be 3 to 4 % over that forecast period.
A great deal of resource information is obtained from SNAC International – the leading trade association on snacks (formerly the Snack Food Association). Strong government links. The Snack Food Association (SFA) was a trade association that represented the interests of the snack food industry in the United States. However, it’s important to note that as of my last knowledge update in September 2021, the SFA has undergone some changes and rebranding. In 2017, the Snack Food Association merged with the National Confectioners Association (NCA) to form a new organization called the National Confectioners Association. This merger aimed to create a more comprehensive and unified voice for the candy and snack industries.
A pellet frying line is a specialized industrial equipment used in the food processing industry. They are particularly used for the production of various fried snacks and pellets. When we talk of pellets in this context we refer to those small, quite often cylindrical or conical pieces of food made from ingredients like potatoes, wheat, corn, or other grains. These pellets are commonly used as the base for snacks like potato chips, many and varied extruded snacks, and other fried or baked products.
Ingredients
The most popular raw materials are potatoes, corn and various tubers such as sweet potato. These products are usually made from a single source of starch or a blend of cereal grains but usually uilt around starch. These raw materials vary in particle size but may require preconditioning and longer residence times in an extruder.
They are usually extruded between 25% and 35% moisture and then subsequently dried to about 12% moisture to maintain stability. Moisture removal is best achieved because the pelleted food dried at low temperatures with high humidity.
When you consider it a pellet frying line typically consists of several components and stages.
Pellet Production
The raw ingredients are mixed in large hoppers and then processed into various pellet shapes. In the initial phase, a basic dough is produced upon mixing and transported pneumatically to an extrusion unit. A variety of ingredients are added including colours, flavours etc.
A typical puffed snack is the peanut classic which is an extruded corn semolina flour and peanut mix. Flavours such as yeast extract and paprika extract for colour are added before extrusion and then further frying.
Pre-conditioning/Conditioning
Pellets sometimes follow a pre-conditioning step to adjust their moisture content (measured as water activity aw) to make them suitable for frying.
Extrusion
A variety of methods exist where the dough is extruded and turned into the fully formed pellet product. There are roughly three categories:
- Precooked ingredients extruded through a low-shear forming extruder
- High-shear extrusion for cooking and cooling.
- A similar type of extruder but used for cooking followed by transfer to a low-shear forming extruder that cools and forms the pellet.
Frying
Always the central stage of the line, where the pellets are submerged in hot oil or another frying medium. The heat and oil transform the pellets into crispy, fully cooked snacks. Frying process parameters are governed by the shape, thickness and content of the pellets. They are usually fried between 150 and 210 C for between 10 and 60 seconds. The average frying time is more between 15 and 30 seconds.
Frying is not the only method of processing. These semi-finished snack pellets are not only fried in hot oil but can also be roasted and baked as well as hot air popped. You can also use methods of expanding and creating low-oil pellet snacks.
Hot air expansion is second only to hot oil frying. It is a direct replacement for deep frying. The use of hot air is considered a much healthier process an reduces the development of acrylamide. The hot air expands the pellets relying on fat in the pellet’s formulation. Any added fat may well come from just the seasoning. It is thought to be a very effective alternative to controlling fat or oil intake as well as how much needs to be added. Whilst it is seen as a healthier process, deep fat frying is viewed as a process that imparts great flavour and so continues in popularity. one of the major drivers is the saving in oil particularly as the supply chain around oil has been severely compromised by war and lack of investment. Oil must also be routinely replaced in frying which adds to that cost. The capital investment in a hot air expansion line is also lower by about 60% compared to an oil based frying line.
The main disadvantage is that it doesn’t work for every type of pellet snack. Certain shapes simply do not expand such as longhollow shapes because the centre sdoes not expand at the same rate if at all as the outer part. A pellet must be shaped in such a way that air can reach all parts of the pellet. HOt air lines must also behave a very rapid transfer and balance of air to ensure uniformity of expansion throughout the pellet..
Air frying is a novel technology which can spray hot air around the raw materials so as to promote the homogenous contact between the foods and the mist of oil droplets in hot air (Andrés, Arguelles, Castelló, & Heredia, 2013). The oil usage of air frying is significantly lower than that of deep frying, favoring the production of low-oil foods (Yu et al., 2020). Furthermore, air frying imparts similar flavor and tasty of the traditional deep-fried products and exerts positive benefits to environment.
One study assessed frying parameters on the quality of pelleted snacks based on wheat flour using both analytical and sensory analysis (BahramParvar et al., 2014). These pellets were available in two colours of yellow and green and were deep-fried at three temperatures between 150 and 190C for 5 different times between 1/2 minutes and 4.5 minutes. These snacks reduced in their hardness, their fracture force and elasticity as time of frying and temperature of frying increased. The article is also worth reading for the application of principal component analysis (PCA).
Whilst not strictly a pellet, studies on tortilla chips also show similar effects from frying. The crisps become crispier as their frying time increases (Moreira et al., 1995).
Oil Filtering and Recycling
To maintain the quality of the frying oil, a filtration system is often included to remove impurities and extend the oil’s life. Some lines also have oil recycling systems. Frying oil is a valuable commodity and has suffered in the last few years from supply chain issues so ensuring quality is paramount.
Seasoning
After frying, the pellets usually pass through a seasoning drum or conveyor where flavorings and seasonings are added to enhance their taste. In some cases the snacks are enrobed in coatings such as chocolate or in breadcrumbs.
Cooling
To reduce the temperature of the freshly fried and seasoned pellets, they are passed through a cooling system, typically a conveyor or an air-cooling process.
Quality Assurance
The traditional approach is to check the quality of the snacks using the human eye. A small team of about 3 to 6 people are present on each conveyoring system prior to packaging to check f
Packaging
The final product is then packaged into bags, containers, or other packaging formats suitable for distribution and retail sale.
Nutrition
Snacks produced from pellets or any other format tend to be extremely high in fat when fried in fat. The deep fat frying process plays a significant part on product quality and the content rises to 38%. This fat fraction affects storage stability (Kita et al., 2009).
Pellet frying lines are used by snack food manufacturers to produce a wide range of popular snack products like potato chips, corn chips, cheese puffs, and more. These production lines are designed to efficiently and consistently produce large quantities of fried snacks while maintaining quality and flavor consistency. They are a key component of the snack food industry, enabling the mass production of these popular snacks for consumers worldwide.
References
BahramParvar, M., Mohammadi Moghaddam, T. & Razavi, S.M.A. (2014) Effect of deep-fat frying on sensory and textural attributes of pellet snacks. J Food Sci Technol 51, pp. 3758–3766 (2014). (Article)
Kita, A., Bąkowska-Barczak, A., Lisińska, G., Hamouz, K., & Kułakowska, K. (2015). Antioxidant activity and quality of red and purple flesh potato chips. LWT-Food Science and Technology, 62(1), pp. 525-531. (Article)
Lusas, R.W., Rooney, L.W. (2001) Snack Foods Processing. CRC Press Boca Raton Fl., USA
Matz, S.A. (1984) Snack Food Technology. 2nd edt. AVI Publishing Co., Inc. Westport, Connecticut. USA
Moreira, R. G., Palau, J., Sweat, V. E., & Sun, X. (1995). Thermal and physical properties of tortilla chips as a function of frying time. Journal of Food Processing and Preservation, 19(3), pp. 175-189 (Article).
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