The gel could help food makers cut costs and achieve a healthier finished product without altering the final taste or texture.
Medium and low-fat mayonnaises usually require reduced oil content and increased starch content along with an emulsifier such as dairy protein or egg yolk. But the new research, published on-line ahead of print in the Elsevier journal LWT Food Science and Technology, suggests that pectin could offer a useful alternative.
"From the results of the present work, it can be concluded that pectin solgel and microparticulate pectin gel played a better role as a fat mimetic which resulted in the low fat mayonnaises with lower calorie than their full fat counterpart but similar texture characteristic properties and had a better acceptability than the WPI/pectin base fat mimetic added to low fat mayonnaise," wrote the authors from the Chinese Ministry of Education and Southern Yangtze University.
Recent figures from Frost & Sullivan reveal emulsifiers, along with fat replacers, are leading growth in the food additive industry: since 2001 the market value of emulsifiers rose by some 5.6 per cent. Emulsifiers are used by food makers to reduce the surface tension between two immiscible phases at their interface - such as two liquids, a liquid and a gas, or a liquid and a solid - allowing them to mix.
The researchers looked at the potential of whey protein isolate (WPI) and low-methoxy pectin to replace 50 per cent of the fat content of mayonnaise. Three fat replacers were studied: a microparticulate pectin gel,a pectin weak-gel, and a microparticulated combination of WPI and pectin. WPI was a gift from Pacific Food Ingredient Tech., China, while the basic pectin was obtained from Danisco.
After comparison with a full fat mayonnaise (100 per cent oil), they report all of the low-fat mayonnaises had higher water content and significantly lower energy content.
In terms of texture, taking into consideration firmness, consistency, cohesiveness and viscosity, the researchers report that only the pectin weak-gel formulation gave similar results as the much-loved full fat sample.
"Sensory evaluation demonstrated that mayonnaises substituted with low-methoxy pectin were acceptable," wrote the scientists.
"This study shows good potential for pectin weak-gel and microparticulated pectin gel to be used as a fat mimetic in mayonnaise," they concluded.
Pectin, with worldwide production estimated at 35,000 tonnes a year, is widely used as gelling agents in jams, confectionery, and bakery fillings, and stabilisers in yoghurts and milk drinks.
The functionality of the pectin is dictated by the chemical fine structure, and the majority of the pectins used currently come from citrus peel and apple pomace. Other sources of the ingredient have remained largely unexploited because of certain undesirable structural properties.
Source: LWT Food Science and Technology
Published on-line ahead of print; doi: 10.1016/j.lwt.2006.11.007
"Rheological, texture and sensory properties of low-fat mayonnaise with different fat mimetics"
Authors: H. Liu, X.M. Xu and Sh.D. Guo