Regulating calcium and acidity may hold the key to improved low-fat sauces and deserts

The findings come from a group of researchers led by Professor Julian McClements from the University of Massachusetts and backed by manufacturing giant ConAgra, who together aimed to find innovative ways to improve the flavour, appearance and texture of reduced-fat foods.

Presenting their findings at the 247th National Meeting of the American Chemical Society (ACS), the researchers revealed that manipulation of calcium levels and the acidity (pH) are vital to improving the acceptance of reduced fat sauces, dressings and deserts.

"By controlling pH and calcium content, we are able to regulate the interactions among fat droplets,"​ explained Bicheng Wu, who worked on the research. "This makes them stick together and form flocs, or clumps."​

The insights from the study are already being fed in to reformulation and NPD efforts, said the team - who suggested that their findings could mean that better-tasting, more eye-appealing and creamier reduced-fat sauces, desserts and salad dressings that could be on the market soon.

The low fat challenge​

Wu explained that this is a difficult challenge because fat has a range of important roles in determining the overall sensory attributes of food products: "It carries flavours, so cutting the fat content lessens the intensity of the flavour.”​

“The appearance, meaning the opacity or lightness, of a food mixture largely depends on light scattering by fat droplets, so high fat content gives a milky appearance to a sauce or dressing,"​ she added - noting that a high fat content is also related to the thick, smooth and creamy feel in your mouth of many products, like pudding, due to the effect of fat droplets on how the liquid flows.

Another problem with slashing the content of fat in a food is that it doesn't make people feel as full, said McClements: "Due to the high calorie count in fat and how the body digests it, fat also affects the feeling of satiety."​

Acidity and calcium​

McClements and his team’s lab work produced a model white sauce with a low fat and calorie content by reducing the levels of fat in the sauce from 10% to 2% - without sacrificing the look and feel of the food. During their lab tests, they found that by manipulating the levels of calcium, and the pH of the model sauce, they were able to create reduced fat foods without the usual issues relating to taste and texture.

The modification of pH and calcium content, helped the team to better control the way the fat droplets in the reduced-fat foods interacted we are able to interact with each other, said the team. 

By controlling these interactions the team were able to create ‘clumps’ of fat droplets – known as flocs – which helped to make the model sauce have the feel of one that was of much higher fat content, they explained.

“We believe the water trapped inside these flocs makes the sauce seem fattier than it really is and preserves the look, feel and flavour,”​ said Wu.

McClements added that his team will soon roll-out extensive taste and smell tests, to assess the wider consumer acceptance and commercial viability of the novel low-fat sauces and dressings.

"Then we will be able to adjust the composition and incorporate other seasoning ingredients into the foods,"​ he explained.

"Since this fat reduction is easy for us now, and the fact that our new products contain healthy ingredients that can be used in a wide range of products means there's a great potential to reach the market in the near future,” ​he said.