Arnaud Jansse, applications engineer, tna
Snacking has become a way of life for consumers across the globe. Driven by a stronger global economy, rising urbanisation rates, growing disposable incomes and a change in consumer lifestyles, the 96.6 billion dollar savoury snack industry is showing no signs of slowing down.However, today’s consumers not only look for convenience, they want products that taste great, are healthy and exhibit a desirable colour, texture and smell for a complete sensory experience. Implementing the right frying equipment is key to achieve this and can add considerable value to snack products.
Which fryer? Finding the best solution for each product
Finding the best solution for the product or product range that is going to be processed is essential.
The type of product, its sensory qualities and physical dimensions all have to be considered when selecting a frying system. Depending on the raw material, there may be special considerations as each type of product has its own set of attributes, unique structure, weight, surface texture and topography which will determine the processing requirements.
Continuous frying, for example, is more suitable for regular potato chips which are typically light in colour, crispy and finely textured. These attributes come from the potato chips being continually processed, for a short amount of time at very high temperatures. In contrast, the batch frying process cooks thicker potato slices or other root vegetables for a longer period of time at lower temperatures, producing high quality chips that are crunchier and darker in appearance. In addition, the desired production rate must be established to determine the appropriate fryer size and type. Typically, batch frying systems can handle capacities of up to 320kilograms per hour. However, the batch-by-batch nature of the process can limit product throughput efficiency. In order to overcome this challenge, installing two or more machines in the process can help food manufacturers to maintain a continuous flow of production.
The overallincrease in the demand for healthier snacks has also resulted in some major technical advancements in frying technology. One of the latest frying technologies for healthier snacks is vacuum frying. With this cutting-edge technology, the product is cooked continuously under low temperature and low pressure conditions from start to finish. At these low temperatures, the degradation of the product’s surface structure is reduced, lowering the amount of oil absorbed and therefore enabling significant fat reduction with minimal impact on product quality. Vacuum frying systems are ideal for producing chips from fruit and vegetables that are high in natural sugars, such as parsnips, apples, kiwifruit or mango, since temperature-related reactions, such as acrylamide formation, are slowed down significantly and in some cases do not occur.
Another technology that can help develop a healthier product range is multi-stage frying. Thanks to a much gentler process, the end product upholds the natural qualities of the raw material, including nutritional value and colour, without the need for additives or colorants, resulting in a more premium product that satisfies the consumer demand for high quality, natural ingredients. Multi-stage frying also enables manufacturers to use healthier oils or oils with distinctive flavour profiles, such as coconut oil or peanut oil, as these types of oils do not degrade as quickly under these gentle processing conditions. As such, manufacturers can maximize oil life and maintain a profitable process and also create new chip varieties with unique and authentic tastes to cater to the palates of the increasingly adventurous consumers.
Oil management – maintaining high product quality
Oil is one of the most important food processing ingredients on the production line, and one of the most expensive. As such, any steps processors can take to reduce loss or wastage of oil can make a significant difference to profitability. Optimising oil life is an essential part of this process and well-designed frying systems should address a variety of needs, including maintaining oil integrity.
When frying, cooking oil can quickly degrade due to the particles breaking away from the product. The debris left in the fryer can burn and carbonise, contributing to oil degradation. This not only damages the quality of the oil but also disrupts cooking efficiency, makes it harder to clean the fryer and ultimately compromises product quality in terms of taste, appearance and shelf life. Frying with degraded oil can also trigger serious health-related side effects caused by the increased levels of fatty acids, oxidised lipids and acrylamides in the end product. To maintain oil quality, the excess particles left behind need to be removed from the oil via a filtration system. If these pieces remain in the oil, they will not only reduce oil quality, but also have a significant impact on fryer efficiency.
Oil pick-up and oil turnover are additional considerations when it comes to oil management. In most frying operations the free fatty acid level of the cooking oil will rise to an unacceptable level if the total volume of oil in the system cannot be turned over within a set amount of time. Turnover occurs by the pick-up of oil into the products as they pass through the fryer. Depending on their physical characteristics, most products absorb oil during the initial stages of frying, lowering optimum oil levels. Potato slices for example, take on 23 per cent of the oil, meaning 77 per cent remains after frying – this oil must be replenished with fresh oil to return levels to 100 per cent. Efficient oil turnover via fresh oil infeed is therefore critical to maintain low free fatty acid levels and optimum oil volume.
The most innovative frying technology incorporates continuous filtration systems to help remove particulate material from the fryer during cooking. Typically, the oil is passed through a filtering system to remove both large and fine particles. The filtered oil is then blended with fresh oil and pumped back into the machine to return oil levels to the optimum level. This ensures that the product is cooked in the freshest oil, assisting manufacturers to produce fried goods of the highest possible quality.
Controls and monitoring – benefits of a flexible customised solution
Designing processing systems with integrated controls and monitoring solutions from the outset puts efficiency at the core of operations. Across the entire food industry, production lines have become increasingly complex with more and more components integrated into the same network to increase output. An effective control system is key to ensuring that the production line remains simple to use and that movement between each area is seamless. Re-tuning these control systems for specific cooking and frying applications, recipes and products enhances efficiency further. Good control systems gather information from the entire line and store it in a central database, allowing plant managers to monitor any unusual activities, pinpoint their location and react quickly and efficiently should an incident occur. This reduces the risk of production flow interruptions and gives operators an enhanced level of control over the quality of the final product.
tna’s frying systems are fully compatible with some of the most advanced controls and integration technology, such as programmable logic controllers (PLC) and supervisory control and data acquisition (SCADA), helping to expose inefficiencies across the entire production line. These systems monitor temperature control to ensure accurate heat regulation during the cooking and frying process. Equally, conveyor drive motors are fully adjustable from a single point to allow greater flexibility in cooking time and product type and processors are able to gauge oil levels and product output precisely. This data can be used to improve transparency throughout production and inform the management of changes to improve performance.
Maximising sustainability – increasing system efficiency
Environmental concerns continue to grow in importance and, as consumers increasingly demand the highest environmental credentials from the products they purchase, food processing specialists are stepping up to help manufacturers in pursuit of greener operations. With rapidly increasing energy prices, keeping energy costs low is essential when trying to achieve a more efficient and sustainable production process. Green credentials must be balanced with manufacturers’ needs to increase overall output, profitability and quality of finished products.
While frying remains one of the fastest heat transfer methods available for cooking, efficient design of heating elements can make a significant contribution towards reducing production costs and physical footprint, without compromising product throughput and quality. Fryers thatuse smaller tube configurationscan significantly increase heat transfer rates and improve system efficiencies up to 80-84 percent. In addition, the amount of tubing inside the fryer determines the fryer’s overall size. As such, the less tubing required, the smaller the space and the smaller the volume of oil required to be heated, decreasing costs in terms of raw material and reducing machine footprint.
Further savings can be achieved with technology that is able recover the energy from the fryer, so it can be re-used. For example, tna’s frying systemsuse the hot exhaust gasses and steam from the fryer and transfer these through a heat exchanger that will produce warm/hot water. This can then be used for other processes like hot washing (potato chips) or in a heat exchanger of a belt dryer (French Fries).
Food safety – achieving the highest safety guidelines
There is increased pressure on manufacturers to prevent food contamination, as contaminated raw materials and cross-contamination during production are common sources of food borne illnesses in food processing plants. Hygienic design of machinery and equipment is the basis for safe food production. Food can, for example, easily become trapped in mechanical joints, compromising hygiene. A simple design with smooth surfaces, no blind spots and no areas, such as corners in which product and microorganisms build up, can help food manufacturers adhere to increasingly strict food safety requirements.
All of tna’s equipment is manufactured from food grade stainless steel, making it easy to clean and capable of withstanding the impact of a high volume of hot oils and fats during processing. Moreover, all good frying systems should be designed so that any water or cleaning fluids completely drain out of the system, following the same path as the oil, leaving no area untouched. The removal of water from a fryer is critical for oil integrity, as well as for user safety. In addition, tna’s fryer systems are simply constructed and contain only the minimum number of moving parts, which are easily accessible to ensure the highest level of hygiene and safety. By specifying easy-to-clean systems from leading suppliers, food processors can significantly reduce the risk of bacterial growth or cross-contamination.
Summary
Frying is one of the most effective heat transfer methods available for delivering unique flavours and enhanced product appearance, through colour development and surface texture, across a wide variety of applications. However, fried goods vary greatly depending on the type of product, and so too do their desired product attributes. As a result, effective frying systems are vital to help manufacturers respond to increasingly discerning consumer demands. As well as providing flavour and texture to create a desirable end product with real consumer appeal, they can also help facilitate increased flexibility to ensure a smooth production process, help manufacturers to meet stringent food safety and hygiene regulations and maximise yield to ultimately help grow sales and increase profits.
