Steam peeling of vegetables is a technology that has been around for almost 50 years. Recent developments have served to underline the hygienic, quality and cost benefits. Ian Healey talked to Eamonn Cullen, steam peeling expert with TOMRA Food, based at the R&D center in Dublin, Ireland. TOMRA Food was the first company to introduce steam peeling to many potato and carrot processors.

Food production companies that have invested in recent years in technology, automation and capacity are now leading the industry’s race to produce higher quantities of food, to satisfy the growing demand for online shopping and eat-at-home foods. Vegetable processing is a good example of how technology can provide operational flexibilities for commercial advantage. Take technology and automation in peeling and sorting processes: these enable customers to process vegetables like butternut in the morning and celery in the afternoon, with very little change to the processing line. And processors could just as easily switch the line between, say, sweet potato, beetroot, carrots, or kohlrabi in varying quantities.

Switching from one product to another is remarkably easy. By simply changing settings using a touch panel, the food processor can start the line for a new product with the confidence that quality and efficiency will be optimized and minimal need for human interaction.

Today TOMRA Food is an industry leader and there are more than 530 TOMRA steam peelers installed around the world. Before the arrival of steam peeling in the 1970s, potato skins were removed by lye-peeling. This was an inefficient process that used chemicals, requiring special care and handling, and consumed high volumes of water to treat the chemical waste from the process. Major food processors were crying out for a new solution and steam peeling was the answer. This uses steam that is already in use in processing plants and enables the more efficient production of high volumes. This advancement has saved many processors thousands of Euros every day. Steam peeling is the most efficient method of removing skin from fruit and vegetables. Lines processing between 1,000 kg/hr – 65,000 kg/hr can benefit from TOMRA’s steam peeling equipment, resulting in significant raw material and energy savings.

Optical sorting technology is where TOMRA is more well-known and indeed this is always the first application when harvesting products. Potatoes and other vegetables are initially processed to remove dirt, stones and other foreign materials. After being ordered as to size and quality, also depending on the customer and final destination, the product is further processed.

Steam peeling entails surrounding each potato with high pressure and high- temperature steam to directly heat the water below the potato’s skin. When the steam pressure is released, the water volume below the skin rapidly expands by more than 1,000 times, creating the force to separate the peel from the flesh. This process can be used for peeling several different vegetables, including potatoes, carrots, beets, pumpkin, sweet potato, kohlrabi, and root celery. It is also used to peel fruits such as apples, which naturally have high moisture.

Some of the main benefits of steam peeling are high quality and process efficiency.  The  yield  and  quality  are much higher than, for example, mechanical peeling by 10-15%. The higher quality can be realized through the increased value of the product  and lower operation costs, including reduced energy consumption. Less waste also increases the final factory output.

An efficient steam peeling process will remove 98% to 99% of each potato’s skin and will equally treat the surface of up to 3,000 potatoes every few seconds. To achieve this, fast pressurization and depressurization of the steam vessel is essential. The key measurement of this is the exhaust efficiency factor (EFF), which is the ratio of the steam shaft cross- section area (mm2) to the vessel volume (liters). Product movement and mixing inside the vessel are also important. There must be a high rotation speed (up to 28 rpm) and consistent movement  of each potato. The EEF of TOMRA’s Eco peelers is two to three times higher than that of other steam peelers with the same volume.

Benefits of TOMRA’s steam peeling equipment:

  • Fastest peeling times for a wide range of vegetables, potatoes, carrots, beets, sweet potato, pumpkins
  • Superior quality and peeling consistency
  • Automated real-time adjustment up to 25% faster than other steam peelers
  • Highest performance solutions on the market, increase by 5% – 10% above others
  • Reduced labor requirements
  • Reduced rejected product
  • Up to 25% lower energy usage
  • Food safety

The TOMRA Steam Peeler’s key benefit over a competitors’ machine is the unique peeling vessel design. Multiple product lifters move the potatoes around. This results in significantly superior peeling performance, as well as peeling very quickly. If the potatoes are mixed uniformly throughout the vessel, they are treated uniformly. A second key advantage is a patented dual-stage steam exhaust system that ensures the steam’s fast release, removing the skins and speeding up the process as such.

Tomra Peeling Module

Combining the high-performance TOMRA Eco Steam Peeler with the TOMRA 5A whole product sorter results in a highly effective TOMRA peeling module that’s also famously reliable, simple to maintain, and easy to operate. This combination overcomes the main challenge for processors: ensuring  that the peeling line is optimized continuously when there are continuous and unpredictable vegetable quality, size, and shape variations. The module is fully automated and for every individual vegetable processed it reports on peel remaining, quality, defects, color, size, shape, and more. It is certainly no coincidence that today 85% of the world’s French Fries are processed using TOMRA equipment.

Covid-19 – Challenges For Food Processors

The COVID-19 pandemic is arguably the most significant challenge the global food processing industry has ever faced. In a crisis such as this, it is important that a customer’s business, as an essential part of society, keeps its activities running smoothly. Food companies are working tirelessly in difficult circumstances to ensure that supermarket shelves, fridges, and freezers are full of interesting and flavorsome products. Food producers are an essential part of creating the meal-time experience that brings and keeps us together.

On the one hand, the foodservice business stopped very quickly, forcing many potato producers to reduce volumes and shut down peeling lines. Even now, a year later, this industry sector is still operating at reduced capacity, and many companies are having to weather financial losses. On the other hand, however, there has been an increase in the consumption of eat-at-home foods, particularly fresh vegetables. Seeing this, some companies have adapted by introducing prepared meals for dine-in consumers.

Many of the challenges brought  by the pandemic in 2020 will continue through much or all of 2021. TOMRA cannot alter the circumstances influencing food demand, of course. Still, they can and will continue to help food processors meet their operational challenges through remote machine monitoring and management and remote customer support and training.

“COVID-19 has impacted TOMRA Food’s business by making it more challenging to visit customers’ sites or host customers at our Demonstration Centers, “says Eamonn Cullen. “But through our technologies, we have found ways to introduce innovative online tools to connect with our customers and to help support their business needs. For example, TOMRA Insight, the cloud- based monitoring platform for sorting lines, enables data-based decision making and process adjustments in near-real-time. TOMRA Visual Assist, our new augmented reality tool,  allows us to provide customers with specialist support remotely, just as if  a field service engineer were standing in front of the machine. And TOMRA’s new Online Demonstration Centers enable customers to see and interact with machine demonstrations via video rather than attending the center in person.”

TOMRA has used increased automation through the COVID-19 situation to improve safety and quality even more. Production facilities have become more remotely controlled, using fewer people, reducing the real and potential introduction of foreign materials. Food traceability is also easier and can be guaranteed to the retailer. This kind of augmented reality has brought TOMRA closer to customers and individuals and has been accelerated by the Covid restrictions.

The Future

TOMRA’s plans for the near future are focussing on waste reduction. Higher pressure steam can be used to peel more product faster. This can increase 6-8% yield saving, which benefits customers, consumers, and the environment alike. As family mealtimes have grown in importance in the last few months, so the expectations in the food which is on the table are also getting higher. Quality, safety and consistency are what TOMRA Food has specialized in for years.

“There is no doubt that, because of the pandemic, over the next months, we face challenging times. The world is adapting to the new restrictions, but struggling to keep up with demand. Rest assured, however, that food supply is ably supported by the watchful eyes of technology and automation to help make home-dining pleasurable.” Eamonn Cullen, Market Manager Peeling, TOMRA Food