The study, published in LWT - Food Science and Technology, found that cakes made from liquid shortening containing a zero trans-fats, and generally a healthier fat profile, showed more uniform grain, finer texture, higher volume, and better shelf-life then cakes made from plastic shortening.
The authors explained that as industry moves away from the use of trans-fats in its formulations, it is important to look at the properties of replacement ingredients, in order to achieve the most effective yet healthy profile.
“Many companies began to use the relatively inexpensive palm oil instead of hydrogenated soybean oil to make zero-trans fat shortenings. Ironically, the high levels of saturated fatty acids in palm oil result in the same cardiovascular problems as do trans-fats,” said the authors, led by Dr Chuck Walker from the department of grain science & industry at Kansas State University, USA.
“For baking companies, a liquid oil plus an emulsifier combination blend would be easy to handle and they could combine different emulsifiers as their requirements change,” they added.
However, the authors conceded that investment in equipment, and a skilled staff to prepare such shortenings would be required.
Shortening is generally a semisolid fat for use in food preparations, especially of baked goods; so called because it promotes a ‘short’ or crumbly texture.
Walker his and colleagues explained that shortening is a major ingredient in high-ratio layer cakes; cakes in which there is as much or more sugar than flour in the formula.
Shortening performs three basic functions in such cake products: it traps air during the creaming process, coats protein and starch particles, and emulsifies large amounts of liquid.
Solid ‘plastic’ shortenings are the most commonly used type of shortening in the baking industry. However they often contain a high proportion of hydrogenated fats, including trans-fats.
Research has highlighted that trans-fats in the diet may increase the risk of coronary heart disease, by raising the levels of LDL cholesterol and lowering the levels of HDL cholesterol.
Walker and his co-workers explained that ‘liquid’ cake shortenings function much like solid shortenings in baking systems, but they offer the user certain advantages, including having a healthier fat profile.
However, the authors noted that “few publications have assessed the performance of liquid shortenings in cake baking systems.”
Four groups of layer cakes were baked using: plastic shortening, liquid shortening, liquid oil, or liquid oil plus emulsifier combinations. Cake performance and firming over-time were then evaluated.
The authors reported that liquid shortening provided the best fresh cake characteristics, whilst liquid oil provided the worst fresh cake characteristics.
Cake firmness was found to change slowly during storage for cakes made with liquid shortening, but for cakes made with liquid oil, firmness increased rapidly.
The characteristics and changes in firmness for plastic shortening were said to be “intermediate.”
The authors said that liquid oil alone “is not suitable for use in cake making”, but added that use of a blend oil and emulsifiers was found to produce high quality cakes.
“Liquid oil with a combination of added emulsifiers performed very similarly in terms of firmness to the liquid shortening …This indicated that emulsifiers played an important role on the improvement of cake firmness shelf-life,” reported Walker and his colleagues.
Source: LWT - Food Science and Technology
Published online ahead of print, doi: 10.1016/j.lwt.2011.03.013
“Evaluation of different types of fats for use in high-ratio layer cakes”
Authors: J. Zhou, J.M. Faubion, C.E. Walker