Influence of added whey proteins and hydrolysates on rheological and textural characteristics of milk chocolate

In order to improve functional characteristics of standard milk chocolate (C) was enriched by the addition of whey protein concentrate (WPC) and whey proteins hydrolyzed by trypsin (H-WPC) in the amount of 6%. The chocolate samples were analyzed by determination of antioxidant capacity, particle size distribution, textural, rheological, and sensory properties. The obtained results revealed that chocolate enriched by whey protein hydrolysate (H-WPC) possesses higher content of total polyphenols (1007.8 ± 96.8 mg GAE/100 g), increased ability to inhibit ABTS radicals (66.30 ± 1.99%), and increased ability to inhibit DPPH radicals (56.34 ± 3.20%), compared to the standard milk chocolate (C) (877.1 ± 56.0 mg GAE/100g; 48.46 ± 2.11%; 48.07 ± 2.80%, respectively). The additional ingredients do not significantly affect the hardness and enthalpy of chocolates. The hydrolyzed whey proteins increase the viscosity of chocolate (11.81 ± 0.11 Pa·s) to a greater extent than non-hydrolyzed whey proteins (9.17 ± 0.09 Pa·s), relative to the control sample (3.53 ± 0.05 Pa·s). Regardless of the fact that the WPC sample has slightly better rheological characteristics and particle size distribution compared to the H-WPC sample, no major changes in the sensory characteristics of chocolate were observed. Based on the results, whey protein hydrolysate can be marked as an exceptional ingredient for improving the quality of chocolate.