Fry Shortening Evaluation 

DonutFryingTest-Header-(940x210)

Doughnut frying shortening made with enzymatically interesterified (EIE) high oleic soybean oil is an excellent replacement for traditional shortenings made with partially hydrogenated oils (PHOs). Recent cake and yeast raised doughnut deep frying studies performed by QUALISOY* compared PHO soybean oil (approximately 31 percent trans fat), a palm/soy blend, EIE conventional soybean oil and EIE high oleic soybean oil.
 
  • EIE high oleic soybean oil produced doughnuts similar to those made with PHO soybean oil; the analysis measured texture, spread, height, oil weeping and more.
  • As determined by a sensory panel, EIE high oleic soybean oil was the most similar to PHO soybean oil in terms of color, mouthfeel and texture.
  • EIE high oleic soybean oil performed on par with PHO soybean oil with fry life, and outperformed EIE conventional soybean oil and a palm/soy blend.

To close the gap between EIE high oleic soybean oil and PHO soybean oil functionality, modifications can be made to fatty acid profiles by blending various oils.

Doughnut Performance

Fatty Acid Composition of Tested Products

EIE high oleic soybean oil produced doughnuts similar in texture, interior grain, spread and height, and size to PHO soybean oil in both cake and yeast raised doughnut frying studies. In the cake doughnut study, EIE high oleic soybean oil produced doughnuts with star-shaped holes similar to those produced with PHO soybean oil; star shape is not a criterion with yeast raised doughnuts. Oil weeping was lowest with doughnuts fried in PHO soybean oil and second lowest with EIE high oleic soybean oil.

Oil weeping is when oil leaches out of the doughnut providing an oily, possibly soggy, taste and mouthfeel. It can lead to inconsistent covering of glaze or powdered sugar. Additionally, excessive weeping results in greasy and stained packaging, which is undesirable.

Oil weeping is when oil leaches out of the doughnut providing an oily, possibly soggy, taste and mouthfeel. Oil weeping was lowest with doughnuts fried in PHO soybean oil and second lowest with EIE high oleic soybean oil.
Oil weeping is when oil leaches out of the doughnut providing an oily, possibly soggy, taste and mouthfeel. Oil weeping was lowest with doughnuts fried in PHO soybean oil and second lowest with EIE high oleic soybean oil.

As determined by a trained sensory panel, EIE high oleic soybean oil performed most similarly to PHO soybean oil in a sensory evaluation of color, mouthfeel and texture.

While EIE high oleic soybean oil absorbed slightly more fat than PHO, optimization of interesterification conditions and fatty acid composition can modify the absorption characteristics of EIE high oleic soybean oil to achieve lower fat absorption.

Oil Performance

The Total Polar Materials (TPM) of EIE high oleic soybean oil was similar to PHO soybean oil and significantly outperformed EIE conventional soybean oil and the palm/soy blend.

TPM measures oil fry life. The TPM percentage rises as the oil is used. Therefore, the lower the TPM rise and overall TPM content, the better.

PHO soybean oil had the lowest degradation rate by p-Anisidine value of all oils tested. Due to significantly lower levels of polyunsaturated fatty acids, EIE high oleic soybean oil and the palm/soy blend outperformed EIE conventional soybean oil. 

p
-Anisidine values quantify secondary oxidation compounds. These secondary oxidation compounds are converted to TPM, resulting in further decrease in oil quality. In addition to increasing the viscosity of the frying oil, these tertiary polymers tend to accumulate on the sides of the fryers resulting in hard to clean residues and undesirable fryer down time.

Total Polar Materials for Frying Shortening
p-Anisidine Value
*Cake doughnut deep frying study conducted in 2016-2017 by QUALISOY in collaboration with Stratas Foods LLC.