The Evolution of Donut Frying

As the process of changing ingredients and formulations is time-consuming and often complicated, most US bakers have already made the switch away from partially hydrogenated oil (PHO) shortenings, according to Frank Flider, QUALISOY consultant. Since the time that the Food and Drug Administration first required labeling of trans fats and announced the efforts to phase out PHOs, bakers have been in the process of conversion.

“Throughout that time, we’ve experienced quite an evolution of PHO alternatives from simple blends and first-generation interesterified shortenings to more sophisticated and functional products like enzymatically interesterified high oleic soybean shortenings,” says Flider, who brings more than 40 years of technical, managerial and marketing experience in the oilseed and agricultural biotech industries to QUALISOY. “All bakers, particularly early adopters of non-PHO alternatives, may consider evaluating their current shortening to make sure that it is performing at the level and providing the quality they desire.”

The interesterification process is very flexible and producers can tailor high oleic soybean shortenings to virtually any specification desired, Flider explains. These shortenings, produced with high oleic soybean oil and fully hydrogenated soybean oil, can have varied proportions based on achieving desired specifications and performance levels to assure optimum performance.

The combination of oleic acid and stearic acid in the shortening closely mimics the performance of trans-fatty acids in terms of melting characteristics, and because the level of polyunsaturates is low, high oleic soybean shortenings have excellent shelf and oxidative stability. High oleic soybean shortenings can offer bakers improved texture, color, flavor, shelf-life and other desirable characteristics.

Comparative testing of PHO donut shortening with high oleic soybean shortening and other alternative shortenings to produce both cake and yeast-raised donuts showed that high oleic soybean shortening performed virtually identically to PHO shortening and was superior to other common alternatives such as palm-soy oil blends and commodity soybean oil shortenings, Flider says.

“Testing was quite rigorous and included the evaluation of texture, color, flavor, shelf-life, oil weeping, height, width, oil absorption and retention of toppings such as icings and powdered sugar,” he says. “Additionally, the size and dimensions of the ‘star’ typical of cake donuts was virtually identical to that observed in PHO-produced cake donuts. These tests demonstrated that high oleic soybean shortening is a direct substitute for PHO shortening and requires no formulation changes for its use.”

Donuts fried in a typical commercial blend of palm and soybean oil tended to be waxier than high oleic shortenings, slightly tougher to the bite and had detectable flavor notes, Flider says. The donuts tended to weep more, the internal star was misshapen and the cell structure was not as consistent. The commodity soybean oil shortening was a bit oilier and tended to weep more than the high oleic soybean shortening.

“Overall, the performance of the high oleic soybean shortening most closely matched the performance of the PHO donut shortening,” Flider says. “Comparatively speaking, there are no special tips or procedures needed when substituting high oleic soybean shortening for PHOs — it is a true drop-in substitute. As is the case for any frying shortening, it’s important to closely monitor and maintain the temperatures of the shortening during frying, assuring that levels are adequate to avoid greasiness and excess absorption.”