From easier cutting and acrylamide mitigation to lower oil uptake and crunchier crisps, pulsed electric field treatment delivers a diverse range of benefits, finds
Michelle Knott
ELECTROPORATION uses a pulsed electric field (PEF) to drill minute pores in the cell membranes of raw vegetables, leading to a diverse range of benefits – both during processing and in end products.
For example, the ability of PEF to help minimise acrylamide in potato crisps is one benefit that has been instrumental in driving uptake. European snack makers are required to do all they can to reduce levels of acrylamide in their products according to the ALARA (as low as reasonably achievable) principle. Put simply, the microscopic holes that, PEF punches in cell membranes allow reducing sugars to leach out during washing, so they cannot be converted into acrylamide during cooking. This reduces the need to blanch potato slices in hot water to achieve a similar result.
“By using PEF you can reduce or remove the need to blanch the product when you’re looking offers PEF in the form of its E-FLO systems. “By using a cold slice wash only there’s an overall energy saving and lower processing cost. In testing we were able to achieve a 57% reduction in acrylamide on stored potatoes, which is a worst-case scenario.”
POROUS MEMBRANES
Punching holes in the membranes also allows other materials to pass through the cell walls. Water is the most obvious and this provides numerous processing advantages by making the plant material softer, as Stefan Tépfl, managing director with ELEA, explains:
“The most visible effect after PEF application is water leakage out of the cells, reducing the turgor pressure and resulting in an overall softer and easier
to cut raw material. This allows an easier processing of fresh-from-the-field crop or hard raw material, such as sweet potato and helps to equilibrate naturally occurring variability within the raw material.”
Easier cutting naturally means there is less wear on the cutting blades, which leads to longer intervals between maintenance. To put a precise number on the improvement in cutting blade life, Mark de Boevere, managing director of Pulsemaster, suggests that 40% less cutting force is needed on average and
an increased knife durability of up to 60% can be expected.
“The treatment results in a smoother cutting surface and less wear of the cutting blades, reducing the knife service intervals,” confirms Tépfl.
Less obviously, creating ‘bendier’ vegetables also offers several additional benefits.
“As vegetable tissues after PEF cut better and show less breakage or rupture, the reduced turgor pressure allows more complicated cuts, such as deep ridge, waffle or lattice,” says Topfl.
Fawcett also notes that easier cutting helps to improve the overall yield: “It’s because you’ve got a better cut with less surface starch that would otherwise be lost in the process. And because you have a more flexible product before it’s fried, it’s less prone to breakage so there’s less crumb.”
Easier cutting can even reduce fat levels in the finished products because the cut surface is smoother, as Tépfl explains: “Improved cutting causes less
cracks in the product surface. Those are the pathway for oil entering during subsequent frying. Notably oil entering those capillaries will also be difficult to
remove – even with defatting equipment. Reduced mechanical tissue damage after PEF will lead to a reduction of fat uptake of 10 % for typical product and frying conditions.”
The distribution of starch is also impacted by PEF treatment, and this affects the quality of the finished product. “The E-FLO increases the amount of starch retained in the potato, which helps to give the chip that all-important bite,” says Fawcett.
ALTERNATIVE PRODUCTS
While much of the focus for development among snack makers has been on the use of PEF with potatoes destined for crisps, it is also helpful for snacks based on other vegetables. Veggie crisps remain relatively specialised, but they are becoming increasingly popular, according to de Boevere: “The market for our PEF-systems expands rapidly. Today PEF is widely used in the potato industry to make crisps, French fries and potato specialities such as hash browns or tator tots. The rise in better-for-you products definitely contributes to increasing sales of our Pulsemaster PEF-systems.”
He highlights the potential of vegetable snacks formed by dehydration and drying, rather than frying, as an especially exciting prospect: “Dehydrated
vegetable snacks is still quite niche but growing. A PEF-treatment prior to drying results in 20% faster drying process and improved quality of the dried
products that rival fresh. Pulsemaster’s PEF enables high-speed, low-temperature drying above or below freezing point while preserving nutritional value,
bioactivity, flavour, colour and a texture better than existing classical methods without PEF.
source: https://library.myebook.com
