PHYSICOCHEMICAL AND RHEOLOGICAL CHARACTERIZATION OF “DULCE DE LECHE”

Effect of formulation and heat treatment on 5-hydroxymethylfurfural formation and quality parameters in dulce de leche

This work assessed the effect of formulation and heat treatment on the formation of HMF, non-enzymatic browning and rheology of dulce de leche (DL). Laboratory scale trials were developed with different DL formulas: whole powdered milk, skimmed milk, and lactose-free skimmed milk, and added sucrose, subjected to different processing temperatures (110°C, 120°C, and 130°C). Additionally, an alternative formulation was designed in which half the sucrose was replaced by 50% tagatose. DL samples were compared with three commercial products in terms of water activity, soluble solids content, pH, colour, apparent viscosity, and HMF concentration. HMF formation in DL was mitigated (35%) in a lactose-free formulation by lowering the process temperature. Moreover, HMF formation was reduced up to 80% replacing sucrose by tagatose without affecting the quality parameters (pH, soluble solids, colour, and apparent viscosity). Decrease in processing temperature and the use of tagatose are viable alternatives for HMF mitigation in DL.

Physico-chemical and compositional analyses and 5-hydroxymethylfurfural concentration as indicators of thermal treatment intensity in experimental dulce de leche

This Research Paper addresses the hypothesis that the type of dulce de leche formula affects formation of 5-hydroxymethylfurfural (HMF) during production and storage. Milk and sweetened condensed milk are products in which the Maillard reaction (MR) defines important characteristics such as colour and taste. There are few studies on the effects of pH, time, concentration, and sugar type on the formation of HMF or other MR markers in DL. Four formulas (varying in the addition of sodium bicarbonate and the type of sugar) were analysed for moisture, lipid, protein, ash, carbohydrate, water activity (Aw), and soluble solids. We found low variability in physicochemical and compositional attributes, but an elevation of HMF indices throughout the manufacturing. We determined that the addition of glucose and the use of relatively high concentrations of sodium bicarbonate caused these HMF indicator increases. These results inform DL research and production by the dairy industries and the scientific community, and highlight the importance of control in manufacturing.

The role of the Maillard reaction in the formation of flavour compounds in dairy products--not only a deleterious reaction but also a rich source of flavour compounds

Dairy products are heated both during processing and by consumers during food preparation; consumers place a high level of importance on flavour when assessing product acceptability. Of particular importance to the flavour of heated dairy products is the highly complex network of Maillard reactions. Much focus has been placed on the undesirable flavours generated through the Maillard reaction and how to minimise the formation of these flavours. However, beneficial flavours can also be formed by the Maillard reaction; dairy products, such as ghee, are formed by heating and are characterised by the unique flavour generated by this chemistry. This review looks at the Maillard reaction as a source of beneficial flavours for cooked dairy products and the application of models to the study of flavour formation in food systems. Models are typically used to study complex reactions in a simplified way; however, they are not always applicable to food systems.

Thermophysical and rheological properties of dulce de leche with and without coconut flakes as a function of temperature

Dulce de leche (DL), a dairy dessert highly appreciated in Brazil, is a concentrated product containing about 70% m/m of total solids. Thermophysical and rheological properties of two industrial Brazilian Dulce de leche formulations (classic Dulce de leche and Dulce de leche added with coconut flakes 1.5% m/m) were determined at temperatures comprised between 28.4 and 76.4 °C. In general, no significant differences (p < 0.05) were observed in the presence of coconut flakes in the two formulations. Heat capacity varied from 2633.2 to 3101.8 J/kg.°C; thermal conductivity from 0.383 to 0.452 W/m.°C; specific mass from 1350.7 to 1310.7 kg/m³; and, thermal diffusivity from (1.082 × 10-7 to 1.130 × 10-7) m²/s. The Bingham model was used to properly describe the non-Newtonian behavior of both formulations, with yielding stress values varying from 27.3 to 17.6 Pa and plastic viscosity from 19.9 to 5.9 Pa.s.