The gel could help food makers cut costs and achieve a healthier finished product without altering the final taste or texture.
"Over the past decade, the consumption of low-fat food products has become more than just a trend," wrote the authors from the Chinese Ministry of Education and Southern Yangtze University. "Largely influenced by health-related concerns, there has been pressure on the food industry to reduce the amount of fat, sugar, cholesterol, salt and certain additives in the diet. Food manufacturers have responded to consumer demand and there has been rapid market growth of products with a healthy image."
Low-fat cheese products are limited by the fact that removal or reduction of fat adversely affecting both texture and flavour. To overcome such obstacles, food scientists have followed several approaches: use of alternative or selective starter cultures, the use of adjunct cultures, or the use of fat replacers.
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 new research, published online in the International Journal of Food Science & Technology, indicates that a pectin gel may enhance the higher texture and mouthfeel of a low-fat cheese.
The researchers used a citrus low-methoxylated pectin gel and added this to an emulsified protein base. The resulting low-fat cheese analogue was compared to a full-fat cheese.
Researchers He Liu, Xue Ming Xu, and Shi Dong Guo report that the pectin gel was found to act as a link to other ingredients, producing a finished cheese that was more compact and with fewer cavities compared to the full-fat cheese and a low-fat cheese prepared without the pectin gel.
Rheological analyses showed that the pectin gel affected the hardness, chewiness and stickiness significantly, with a positive effect reported for texture and mouthfeel.
"The panellists found the differences in texture and mouthfeel between full-fat and low-fat cheese analogues with or without pectin gel addition. However, the full-fat and low-fat cheese analogue without pectin gel addition were poorer in texture and mouthfeel as reflected by their lower score," wrote the researchers. "The lower score in mouthfeel and texture of full-fat samples was likely due to the denser microstructure which made the sample too hard."
"Based on the sensory evaluation results, [we are] optimistic to apply pectin gel to substitute partial fat to prepare cheese analogues," they concluded.
The research follows similar work from the same group that looked at the potential of pectin gels to enhance functional properties of low-fat mayonnaise (LWT - Food Science and Technology, doi: 10.1016/j.lwt.2006.11.007).
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: International Journal of Food Science & Technology (Blackwell Publishing)
Published online ahead of print, 15 February 2008, doi: 10.1111/j.1365-2621.2007.01616.x
"Comparison of full-fat and low-fat cheese analogues with or without pectin gel through microstructure, texture, rheology, thermal and sensory analysis"
Authors: H. Liu, X.M. Xu, S.D. Guo