Production of Doce de Leite (DL) added with microparticulated whey protein

Introduction:

Doce de Leite (DL) is a typical product of South America, where Brazil, Argentina, and Uruguay have the largest consumer market and production of this food [1]. Microparticulated whey proteins (MWP) are a combination of native and denatured proteins with controlled particle size aimed at enhancing thermal stability during processing. They can be used to modify nutritional attributes or rheological characteristics of foods, yet their application in DL production and their potential impacts have not been reported in the literature [2]. Therefore, the objective of this study was to produce and characterize doce de leite with added MWP as a substitute for skim milk powder at two substitution levels (2.1% and 4.2%). DLs were produced by using three different dairy ingredients (skim milk powder (SMP), whey protein concentrate (WPC), and microparticulated whey proteins (MWP)). The MWP used in DL production had an average particle size of 4.88 ± 0.38 μm, α-lactalbumin concentration of 2.35 g.100g-1, and β-lactoglobulin concentration of 0.96 g.100g-1, which resulted in an additional denaturation of approximately 62.3% and 96.5% for each protein fraction, respectively, due to microparticulation. The endpoint of doce de leite production was determined by mass balance and soluble solids content. After production, compositional analyses and rheological tests were conducted to study how the substitution for milk with MWP could modify the rheology and final composition of the product. Total solids, moisture, soluble solids, fat, and acidity did not show statistical differences, whereas protein, ash, carbohydrates, and pH exhibited some variation. The moisture, protein and ash values are in accordance with current legislation in Mercosur, however the fat value was below the stipulated level. Four indicators of the Maillard reaction were analysed. HMF (5-hydroxymethylfurfural) concentration determined in the samples showed no statistical difference between the formulated products. Six elements (Ca, Cl, P, Mg, K, and Na) were quantified in the DL ash by means of energy-dispersive X-ray spectroscopy (EDS), with concentrations close to values reported in the literature. In terms of colour requirements, the products added with SMP presented a darker colour than the products added with WPC and MWP in the two concentrations studied. In addition, doce de leite produced with MWP exhibited higher apparent viscosity, hardness, and gumminess compared to products with SMP and WPC at both substitution levels, indicating that microparticulated protein can be used to modify the viscosity and organoleptic characteristics of doce de leite without the need for additional thickening agents.

References cited in the introduction:

[1] P. C. Lima, et al. Food Science and Technology (Brazil), 2020, 40. [2] J. Toro-Sierra, et al. Dairy Science and Technology, 2013, 93.

[151] De Paula, I. L.; Vitral, J. M. P. M.; Lazzarini, P. F.; Wolfschoon-Pombo A. F.; Schwazenbolzs, U.; Henle, T.; Perrone, I. T.; Stephani, R. Production of Doce de Leite (DL) added with microparticulated whey protein, 2024.