How Thermally Glycated Whey Protein Affects Starch Properties

You might know that wheat starch can gelatinize and form a gel when heated. But what happens when you add thermally glycated whey protein isolate, or gWPI, to the mix? This is made by heating whey protein isolate with lactose. Scientists found that gWPI can really change how wheat starch gels. First, gWPI can slow down the swelling and thickening of wheat starch, which is what we call gelatinization. It also can make the gel stronger and better in terms of properties. Tests using RVA (Rapid Visco Analyzer) and DSC (Differential Scanning Calorimetry) showed that adding gWPI could lower the viscosity and energy needed to gelatinize the starch. For instance, when 12% gWPI was added, the peak viscosity and gelatinization energy went down by 36 centipoise and 3. 11 joules per gram, respectively.

What's happening? Well, gWPI seems to compete with wheat starch for water. This means it can prevent the starch from absorbing as much water, which stops it from expanding too much. Also, gWPI can form a kind of barrier on the starch surface using hydrogen bonds. This prevents amylose, a part of starch, from leaking out. As a result, the gel particles become smaller and lose some of their ability to bind with iodine. The gel's behavior also changed when gWPI was added. It became less stringy and more like a fluid that thins out under force, which we call shear-thinning. The structure of the starch also changed. With gWPI, the starch molecules didn't bunch up as much. This made the starch shorter and the gel properties different. So, gWPI can act like a regulator, helping to control how starch gels. This might be useful in food production to improve starch properties. But remember, these changes are all part of a complex process involving chemistry and physics.

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