The role of food thickeners in food(2)

Polydextrose is a good prebiotic, fermenting in the intestinal tract can lower the intestinal pH from 7.24 to 6.44, facilitating the growth and proliferation of probiotics such as lactic acid bacteria and bifidobacteria. In yoghurt production and processing, polydextrose can enhance the dietary fibre content and taste of the product as it remains stable at low pH. In low-fat or fat-free products, it effectively prevents water analysis, improves water retention and enhances the texture and taste of the product.

Studies have shown that when polydextrose is added to yoghurt products at 1% (W/W), it can achieve enhanced viscosity and sweetness, resulting in a richer product. Polydextrose improves the viability of other bacteria in yoghurt and effectively extends the shelf life of yoghurt.

When polydextrose is added to yoghurt at 3% (W/W), it facilitates the fermentation of yoghurt, increases the activity of lactic acid bacteria, reduces the precipitation of whey and plays a key role in the organisation of the product, which achieves the best curdling effect with moderate acidity and sweetness. When 4% (W/W) of polydextrose is added to curdled yoghurt, the product has a fine texture, moderate sweetness, significantly reduced whey precipitation, good stability and polydextrose retains the flavour of the product well, extending the shelf life.

2.3 Application in soft drinks

Sodium carboxymethyl cellulose is the most common thickening agent in acidic beverages, as it is easily soluble in water, it can form a high viscosity solution in water. Sodium carboxymethyl cellulose is most commonly used in cow's milk due to its acid resistance. Sodium carboxymethyl cellulose effectively prevents the precipitation of casein and extends the shelf life of dairy products. Sodium carboxymethyl cellulose also improves the suspension stability of fruit and vegetable beverages, preventing sedimentation and effectively maintaining product stability and appearance.

Xanthan gum has the highest viscosity of natural gum and is soluble in cold water, and is widely used in the production of soft drinks. Aqueous solutions of xanthan gum have a typical pseudoplastic flow in which the viscosity decreases in the presence of shear force and returns when shear force disappears. While most gums are unstable over a wide temperature range, the viscosity of xanthan gum varies much less than other gums. Xanthan gum also has good salt resistance and is not affected by salt precipitation when heated.

Xanthan gum is also used in pulp and protein beverages to enhance the suspension of active ingredients such as casein. The pseudoplasticity of xanthan gum enhances the viscosity of beverages, resulting in a thicker, less sticky taste. In addition, xanthan gum has a good compatibility, when used simultaneously with other thickening agents will have a synergistic effect.

Up to now, the application of thickeners in food in China is not perfect, the production technology is weak, and the research and development of thickeners is still in its infancy. With the increasing standard of living, consumers' requirements for food flavor, taste, appearance, etc. are gradually increasing, the future application of thickeners in food processing has a broad development space and prospects.