Stability is the other key to frying oil — both its usage and its impact on the finished food.
“Oil stability determines oil frying life and food shelf life,” Dr. Liu said.
The more stable the oil, the longer it can be used in the fryer before it begins to break down. The faster that happens, the more often the oil needs to be refreshed in the fryer and the more often the fryer needs to be cleaned, which leads to more downtime.
“The main culprit to oil instability is polyunsaturation,” Mr. Flider said. “The more polyunsaturation you have in the oil, the more susceptible it is to oxidation or instability.”
Oxidation goes hand-in-hand with shelf life. With higher stability, frying oils last longer in the fryer, and the donut, pastry or snack chip gets longer shelf life.
Phos offered bakers and snack producers plenty of stability — a quality that must also be achieved by any replacement in the new pho-free reality. Early attempts to replace phos for frying faced challenges in stability, but suppliers offer bakers and snack producers several options now.
“The early interesterified oils were a combination of the polyunsaturated oils like canola and commercial soy with the hard stock, and that left too many polyunsaturates and too much room for oxidation,” Mr. Flider explained.
Canola and soy oil offer bakers and snack producers options low in saturated fat, but if not blended with something more stable, these oils force formulators into some trade-offs.
“Liquid oils low in saturated fat like soybean and canola oil can serve for frying but with a shorter fry life and the risk of off-flavor development,” Mr. Doucet said.
Today, high-oleic and palm oils can provide the stability necessary for fried foods.
“On just a performance level, phos and shortenings have historically provided long fry life and good shelf stability at a cost-effective price point,” Mr. Guy said. “The vast majority of these fry life and shelf stability needs can be met with Bunge’s non-pho high-oleic options and blends.”
Bunge’s algae oil is heat stable with a high smoke point, and the company also recently began offering a non-G.M.O. sunflower oil that has a longer fry life.
Mr. Doucet pointed out, however, that while high-oleic oils have the desired oxidative stability to replace phos, they do not have the capacity to form the semi-solid structuring necessary for donut applications. To work in applications that need fat solids, these oils need to be blended with others.
Stratas Foods developed a next-generation high-oleic soybean shortening. It uses the company’s proprietary Flex crystallization technology and a more stable liquid oil component to provide a pho alternative.Frying fats have a lot of heavy lifting to do between transferring heat and conferring onto baked goods and snacks their final structures, flavors and textures. Pho replacements must be able to accomplish both of these tasks while also remaining efficient from a processing standpoint. With some testing and strategizing with food scientists, bakers and snack producers can find the right solution for their frying fat needs.