By controlling the release of serum from a gel, which plays a clear role in the juiciness of a food product, the overall sweetness perception of the gel could be controlled, and allow formulation with less sugar but equal sweetness, according to findings published in Food Hydrocolloids.
“The unique semi-solid character of food gels is primarily due to their ability to entrap the serum in their structure,” explained researchers from the Top Institute Food and Nutrition, Wageningen University & Research Centre, and NIZO Food Research.
Fred van de Velde from NIZO Food Research and co-author of the study explained that serum release is the separation of liquid from a food product under compression. “It relates to the release of liquid from a food product during mastication (hard products) or compression between tongue and palate (soft foods). Sensory attributes that are related to this physical property are: juiciness, separating, watery,” he said.
Van de Velde told FoodNavigator that the research is relevant for meat, meat products and meat alternatives.
“In a more broader perspective this finding can be relevant for each food product that allows the expulsion of liquid during chewing, without negatively affecting the overall sensory performance of the product,” he said. “Thus this can include desserts, confectionery and so on.”
Same sweetness, less sugar
Results showed that ‘serum release’ was also an important predictor of the perception of a gel’s sweetness. The sweetness perception of a gel with 12 per cent serum release, for example, was found to be the same as gels with 2 per cent serum release but containing 30 per cent more sugar.
“The modulation of the serum release in food gels appears to be a powerful textural tool to enhance sweetness,” wrote researchers from
“Using this approach allows to reduce sugar levels without loosing taste intensity,” they added.
The technique could also be applied to salt, suggested the researchers led by Guido Sala.
Both sugar and salt reduction are key drivers for the reformulation of processed foods, particularly in the light of rising obesity rates and the perceived detriment to cardiovascular health of high sugar and salt foods, respectively.
Study details
The Dutch researchers prepared gels from whey protein isolate (Bipro, Davisco International), gellan gum (Kelcogel F, CP Kelco) and glucono-d-lactone (GDL, Jungbunzlauer) with different concentrations of whey protein isolate and gellan gum, while maintaining the overall protein:polymer ratio.
The data showed that an increase in the gellan gum concentration produced increases in the size of the pores in the protein network. The serum release also increased, noted the researchers. The pore size also increased as the sugar content increased, but this reduced serum release, they noted.
“The scores for the attribute sweet were significantly higher for gels with higher serum release,” wrote Sala and his co-workers. “Increasing the serum release from 2 wt per cent to 35 wt per cent induced an increase of the scores for this attribute by 30–45 per cent.
“The increase of the scores was relatively larger at lower sugar concentration. When increasing the serum release by a factor 5 to 6, the same sweetness can be perceived with 30 per cent less sugar,” they added.
The study was funded by the European Union’s 7th Framework Programme “Design and development of realistic food models with well-characterised micro- and macrostructure and composition (DREAM)”.
Source: Food Hydrocolloids
Volume 24, 494-501
"Serum release boosts sweetness intensity in gels"
Authors: G. Sala, M. Stieger, F. van de Velde