Potato crisps, also known as potato chips in some countries especially the USA, are as popular a snack as they always were. It’s all about those wafers made from thinly sliced and fried potatoes. They are recognised the world over for that characteristic crispy and crunchy texture, as well as their savory and sometimes salty flavor.
Quality
Crisps or chips are fried to 2% moisture content. They are light yellow in colour and have a classic fried potato flavour, aroma and extremely crispy texture. Gould defined the ideal colour as an Agtron Red Value greater than 51. The fat content is not meant to exceed 32 to 40%. In terms of any defects, there must be less than 15% blisters, less than 10% minor defects and less than 5% minor defects.
The ingredients are key. Potato crisps are primarily made from potatoes, vegetable oil (such as sunflower oil or canola oil, and salt. Additional flavorings and seasonings can be added to create various flavors, such as salt and vinegar, barbecue, sour cream and onion, cheese, or chili.
Processing
The handling of the potatoes is very similar to that employed in producing french fries. An average sized potato produces 35 to 38 thin crisps. Large manufacturers can produce up to 4 million bags of crisps per week when potatoes are available in season.
To make potato crisps, high-quality potatoes are first selected and washed to remove dirt and impurities. They are then sent to a peeler which removes the skin by abrasion. Large manufacturers of any potato product can peel up to 6000 kg/hr. In many manufacturing systems, the smaller potatoes are sent to the slicer whole otherwise any large potatoes are cut in half, The potatoes are then sliced very thinly, either by hand or using automated slicing machines. The slices are usually washed in a large rotating drum using cold water for about a minute to remove fragments of skin and unattached starch particles.
Excess water is blown off the chips using an air dryer.
These thin slices are then fried in hot oil at 370ºF for about three minutes until they turn golden brown and become crispy. The fryer is usually a large open trough containing vegetable oil. During frying, any water present in the raw material evaporates, and is partially replaced by oil. The frying oil constitutes up to 40% of the finished product, and consequently influences its sensory properties After frying, excess oil is drained as the crisps travel on the conveyor. An open mesh conveyor is used to help the oil be removed. The crisps are seasoned with salt or other flavorings which are immediately added relying on the oil to partially allow the powders to adhere to them.
Any excess oil is collected and checked to see if it can be reused otherwise it is discarded in oil drums for further refinement.
For all intents and purposes it is the frying process which we alluded to a moment ago is the second key to creating that texture sensation. The quality of the potato used has to have an enormous impact on the quality of the texture of course. Our crisps must have a light and delicate crunch, which is one of their defining characteristics. The thin slices of potato become crispy when fried, resulting in a satisfying, audible crunch when you bite into them.
The quantity of oil absorbed impacts the degree of crunch. Too much oil and the crisp is literally oily and fatty because the fat content is too high. Too little oil and the crisp loses its bite and tastes harsh and unsophisticated.
Controlling the frying process is vital. The amount of oil absorbed depends on the frying temperature and the quality of the oil used. It also influences the length of time the crisp spends in a process. This process has been investigated over many years because of its deep significance. In general, crisps are fried within a narrow range at high temperatures (175–190 °C). Temperatures above 175 °C favour the formation of acrylamides, known to be potential carcinogenic substances. A number of producers are looking at processing where the frying temperature is reduced without losing the crispiness. Even air frying is now getting in on the act.
The best frying oil for crisps is palm oil or its fractions, and the high-oleic sunflower, rapeseed and soybean oils. Palm oil has its detractors because of the environmental impact of growing so many palm trees but in the current climate of supply chain issues surrounding sunflower oil, it has become in the last few years a major commodity. Hydrogenated vegetable oils are very versatile – i.e. sunflower, rapeseed and soybean. The processor is rather spoilt for choice and each one can lend a particular characteristic crunch to the potato crisp.
One particular study by Kita et al (2007) in Poland examined the impact of different frying oils on both fat content and texture of potato crisps. Their finding was that the oleic acid content affected the crispiness. They also noted that the higher the frying temperature the lower the fat content of the crisps. If it was below 170ºC then the hardness of the crisp was reduced.
Potato crisps come in a wide variety of flavors to cater to different tastes. Some popular flavors include classic salted, barbecue, sour cream and onion, salt and vinegar, cheddar cheese, and jalapeño. These flavorings are often applied as a powder or seasoning after frying.
Before the crisps are packaged, a visual system, sometimes relying on machine vision is used to inspect the crisps for brown spots, for limpness and other defects. The losses are usually minimal – about 3-5% on a well-managed routine run. If the frying oil is poor quality or there have been issues in running the line, whole batches of crisps have to be discarded.
Potato crisps are typically packaged in airtight bags or containers to maintain their freshness and crispiness. The bags are often designed with eye-catching graphics and branding to attract consumers.
Potato crisps are usually oval or round in shape, but they can also come in various shapes and sizes, including ridged or wavy varieties. The thickness of the crisps can also vary.
Potato crisps are an extremely popular snack worldwide and are commonly found in supermarkets, convenience stores, vending machines, and snack bars. They are often enjoyed as a standalone snack or as a side dish with sandwiches, burgers, or other meals.
Dietary Considerations
Potato crisps are typically high in calories, fat, and salt, so they are considered a less healthy snack option when consumed in excess. However, some brands offer baked potato crisps as a lower-fat alternative.
Potato crisps are a snack known for their crispy texture and a wide range of flavors. They have become a staple in the snack industry, enjoyed by people of all ages around the world.
References
Kita, A., Lisińska, G., & Gołubowska, G. (2007). The effects of oils and frying temperatures on the texture and fat content of potato crisps. Food Chemistry, 102(1), pp. 1-5.
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