a b s t r a c tThis study evaluated the effect of addition of modified starch on the characteristics of dulce de leche, being conducted in two phases. In the initial phase, starches were evaluated for their ability to provide viscosity in model solutions representing the composition of dulce de leche during processing, thus evaluating the effect of solid concentration, which occurs during production, on the ability of starches to increase viscosity in simulated conditions of heat treatment and agitation promoted by Rapid Visco Analyser (RVA). It has been chosen 2 starches and 2 concentrations of soluble solids from the results of the initial phase, being employed as a criterion of choice starches with the highest viscosities at each solid concentration processing phase. In the second stage, 6 treatments were applied in triplicate, in which it's been determined the chemical composition, the instrumental color, texture profile and yield. Analyses were performed on crystallization of lactose during storage. According to the established conditions of the experiment, the starch configures itself as an important optional ingredient for the production of dulce de leche providing then longer shelf life without change in texture, composition, yield and sensory characteristic.

O leite de vaca é o mais consumido no Brasil e na maioria dos outros países. Neste produto a β-caseína representa aproximadamente 30% do total de proteínas, podendo esta estar presente como duas diferentes variantes de acordo com a genética do animal: β-caseína A1 e A2. O peptídeo opioide β-casomorfina-7 (BCM-7) pode ser liberado durante a digestão da β-caseína A1, no entanto sua liberação durante a digestão da β-caseína A2 é pequena à inexistente. Este artigo tem como objetivo discutir o potencial efeito do consumo das variantes genéticas A1 e A2 da β-caseína sobre o trato digestório. Existe um corpo de evidências apontando para a presença BCM-7 como responsável pela síndrome de intolerância ao leite não relacionada com a lactose, com efeitos sobre motilidade gastrintestinal e ação pró-inflamatória. Dada a complexidade das reações bioquímicas e fisiológica que se observam no ambiente intestinal é razoável esperar que os sintomas, quando presentes, irão variar dependendo da sensibilidade interpessoal. A avaliação do consumo de leite A2 como alternativa dietética entre indivíduos que reportam desconforto gastrointestinal por consumo de leite de vaca (não associado à lactose) é recomendável tendo em vista a importância que os lácteos representam no aporte de nutrientes fundamentais à saúde humana.

17Denaturation and interaction of different proteins occur in different forms and intensity 18 when the pH value varies in accordance with the medium in which they are located. 19This study aimed to verify the influence of whey protein/casein interaction in the 20 evolution of viscosity at different pH values, using the Rapid Viscosity Analyzer (RVA) 21 as the thermal processing simulator. Samples of commercial whey protein concentrate 22 (WPC) and milk protein concentrate (MPC) have been analyzed. The results of this 23 study can be applied in the development of products obtained from dairy powders such 24 as processed cheeses and yoghurt.25

No abstract

Protein systems (PS) are routinely used by companies from Brazil and around the globe to improve the texture, yield, and palatability of processed foods. Understanding the synergistic behavior among the different protein structures of these systems during thermal treatment under the influence of pH can help to better define optimum conditions for products and processes. The interpretation of the reactions and interactions that occur simultaneously among the protein constituents of these systems as dispersions during thermal processing is still a major challenge. Here, using a rapid viscosity analyzer, we observed the rheological changes in the startup viscosities of 5 PS obtained by combining varying proportions of milk protein concentrate and whey protein concentrate under different conditions of pH (5.0, 6.5, and 7.0) and heat processing (85°C/15min and 95°C/5min). The solutions were standardized to 25% of total solids and 17% of protein. Ten analytical parameters were used to characterize each of the startup-viscosity ramps for 35 experiments conducted in a 2×3 × 5 mixed planning matrix, using principal component analysis to interpret behavioral similarities. The study showed the clear influence of pH 5.5 in the elevation of the initial temperature of the PS startup viscosity by at least 5°C, as well as the effect of different milk protein concentrate:whey protein concentrate ratios above 15:85 at pH 7.0 on the viscographic profile curves. These results suggested that the primary agent driving the changes was the synergism among the reactions and interactions of casein with whey proteins during processing. This study reinforces the importance of the rapid viscosity analyzer as an analytical tool for the simulation of industrial processes involving PS, and the use of the startup viscosity ramp as a means of interpreting the interactions of system components with respect to changes related to the treatment temperature.