The better the peeling process, the better the potato and, possibly, the wastage can be reduced, too. But wastage is not everything, it’s the degree of cleanliness that is just as important. So which peeling method is best for you? We take a look at some developments.
In our modern world, huge quantities of potatoes are peeled in various ways every day. Getting the skin off cleanly and leaving most of the flesh looking clean and healthy is the object of the peeling process. Peeling has, over the years, become even more scientific and is in constant motion thanks to research and the never-ending search for a better, more economically viable solution. Processors must not consider the waste level alone, says Dieter Dornow, managing director of Dornow Food Technology in Dusseldorf, Germany, because a low level of waste can be achieved with nearly every machine. “No, we must, at the same time, consider the desired degree of cleanliness of the peeled potato. This is the efficiency of peeling.” What needs to be considered is that many potato product manufacturers have different requirements regarding the degree of cleanliness of the peeled product. Crisp manufacturers work with a waste percentage of 4-10 per cent while chips or French fries makers average a wastage of 15-20 per cent. Then, at the other end of the scale, commercial potato peelers for large-scale catering businesses estimate a wastage of 3-45 per cent while poorly maintained or badly designed machines can give a wastage of 50 per cent. The canning industry also works on a high wastage percentage as, in some cases, bad potatoes are simply rejected. Putting intentionally high rates of wastage to one side, there are levels which can be avoided. Says Dornow: “With regard to steam peelers, too much or too little pressure in the steam vessel could have negative or positive consequences. In the field of mechanical peeling technology there are many designs which produce unwanted, unnecessary waste. But the tricky thing is that unnecessary waste is often not recognised in these operations.” So, the best possible peeling of potatoes means the removal of the outermost layers up to a desired and required depth in a way that is as gentle and even as possible in the shortest time. This is where steam peeling and mechanical methods come into play. Tummers Methodic says their peeling and polishing machines help manufacturers reduce costs and improve quality. Lower peeling loss, intensive – but not aggressive – polishing, and lower maintenance costs can be achieved through the Dutch company’s wide range of machines, all based on innovative designs. The complete steam peeling lines can be executed as a turn-key project, with the patented ZicZac brusher seen as a genuine improvement taking into account that there has been very little development in the field of peel removal of steam-peeled products in the potato and vegetable industry. All the other alternatives in the market are based on old designs dating back 30 years or more. Brushing after steam peeling, says Tummers, will give a substantial improvement on the peel loss with the process of dry peel removing after a steam peeler or a chemical peeling process for products like potatoes, carrots and numerous other tubular shaped products. The machine consists of two brush frames and an undercarriage. Brushes are installed in each brush frame. One frame is fixed on the undercarriage, and the other can move horizontally. This is mounted on the undercarriage on stainless steel wheels. Each brush unit is driven by a motor with a toothed belt drive. The brush shafts are fixed in heavy spherical roller bearings, with extra protection against the entry of water. A casing is fixed on each brush frame for collecting peels. Two channels collect the peels and transport the same out of the machine. The product space between the brushes is limited by removable side sheeting. The distance between the two halves of the machine can be manually adjusted horizontally using spindles, both for various tuber diameters and also for cleaning and maintenance. This product uses abrasive rollers to peel bulb-shaped and tuberous products. Each roller is separately driven by a reduction gear motor and is equipped with removable shaft journals. The advantage of this is that the machine has no chain wheels, chains and chain tensioners. A sprinkler hose is installed inside the machine over its entire length and can be adjusted on two sides. The machine has two hinged protection hoods for cleaning purposes. The peeler can be supplied with an inlet and an outlet and with a funnel at the bottom for product waste. Dornow say their roller peelers, placed at the end of a line of steam peelers, are an integral component that offer huge benefits when it comes to minimising peeling waste and producing perfect goods. With bad quality potatoes, for instance, with deep set eyes and damage spots, the roller peeler time can be extended with the fast rotating peeling rollers and slower rotating auger will ensure the required abrasion. Dornow says the economical benefit of this is a lower waste percentage with a high degree of cleanliness and energy saving achieved through not extending the steam peeling process. He says while steam peeling removes peel evenly, this is not always the case with mechanical machines like batch peelers, drum peelers, multi-disc machines and roller peelers with rollers in a stationary position. When Dornow built the first roller peelers in Europe more than 30 years ago, the trigger was a customer who peeled large quantities with batch peelers but he wanted a machine in which he could leave the potatoes as long as he wanted without them being peeled flat. Today, Dornow offers about 70 models of peelers with roller diameters of 10-15cm and auger diameters of 0.5-2.5m. Various designs include radical roller peelers which can, for example, quickly peel bad waste potatoes to make them useable for human consumption; make large potatoes smaller and quickly remove damage spots. Dornow’s universal skin removing rollers are used downstream of steam peelers in order to remove any remaining peel. The introduction of micro-fine peeling means even less waste and that the surface of the peeled potato is as smooth as glass. To ensure low levels of waste, it is important to carry out running measurements, says Dornow, and his company’s FLA-S peeling control device detects the possibility of flat peeling. Providing more accurate control than continuous abrasive peelers, Heat and Control Multi-Stage Batch Peelers can save potato processors thousands of dollars annually and reduce cleaning costs for fryers and other downstream equipment, says the US-based company. The uniformly smooth surface produced by polish-peeling results in more efficient slicing and cleaner fryer operation. For fresh potato applications, it minimises the usage and carry-over of anti-oxidants onto finished product, and promotes a more stable product colour. US-based Heat and Control offers BP Batch Peelers that are simple to clean and all abrasive surfaces can be easily removed. Batch size and dwell time are programmable, and each peeler automatically empties and reloads at the end of each peeling cycle, optimising efficiency. Optional weigh-in/weigh-out systems are also available to precisely control peel loss. Their VersaPeel® multi-stage batch peeler was designed for potatoes, root crops and vegetables peeled in abrasive/brush peelers and significantly reduces peel loss and improves finished product quality. VersaPeel uses progressively finer abrasives and/or brushes for maximum peel removal, even within eyes and recesses. Potatoes finished in VersaPeel retain their natural shape and have a smooth, polished surface with virtually no flat spots, which reduces scrap generated by slicers and cutters. For fresh potato applications, the smooth finish minimizes the usage and carry-over of anti-oxidants onto finished product, and promotes a more stable product colour. Peel loss savings with VersaPeel can save processors thousands of dollars annually. For example, potato chip processors can greatly reduce the amount of fresh potatoes purchased and still maintain current production levels – or they can dramatically increase capacity without using more potatoes, saving costs and increasing production. These are just some of the options available to make the processor’s life easier, the product better and the costs lower.
