Characterization of Melanoidins and Color Development in Dulce de Leche, a Confectionary Dairy Product With High Sucrose Content: Evaluation of pH Effect, an Essential Manufacturing Process Parameter

Effects Provided by Sugar Substitutes upon the Quality Indicators of Model Systems of Sweetened Condensed Milk in Storage

Sweetened condensed milk (SCM) is a product widely used by both consumers and other food production branches. However, it contains a lot of sucrose. This study aimed to examine the effects provided by sugar substitutes, such as trehalose, isomaltulose, and polydextrose, upon the SCM sensory profile and valuable quality indicators, such as water activity, viscosity, acidity, crystals size, and Maillard reaction potential (browning index, color change, loss of free amino acids). The study was performed by making model systems of SCM (MSCMs) using the method of reconstitution of powdered ingredients. All the presented carbohydrate compositions in MSCMs provided Aw value typical of intermediate-moisture food, which contributes to the long-term shelf-life of the product. However, only 2 MSCMs with compositions consisted of isomaltulose, trehalose (22.55% and 22.55%); trehalose (28.19%), sucrose (5.64%), polydextrose (5.64%), isomaltulose (5.64%) showed the stability of Aw within 14-d storage period. Trehalose and polydextrose in MSCMs with mono-carbohydrate added fraction demonstrated their high structure-forming ability expressed in high values of dynamic viscosity (>30 Pa·s), provided not by crystallization. MSCMs containing trehalose in predominant amount in the carbohydrate compositions (≥50%) showed lower average crystal size (<16 μm) compared with other MSCMs with di- and tetra-carbohydrate added fractions with predominant amount of isomaltulose and polydextrose. Isomaltulose and polydextrose added to MSCMs led to pronounced browning, while trehalose and sucrose reduced this effect in MSCMs with di- and tetra-carbohydrate added fractions. Addition of 22.55% of polydextrose to carbohydrate fraction of MSCMs caused bitterness, while 5.64% didn't affect the taste. Based on the results of all the research conducted the most optimal carbohydrate compositions to produce SCM with lower calorie, sucrose contents and stable adequate values of processing and sensory properties were trehalose (22.55%) with isomaltulose (22.55%) and trehalose (28.19%) with sucrose (5.64%), polydextrose (5.64%), isomaltulose (5.64%).

Antioxidant and Functional Activities of MRPs Derived from Different Sugar-Amino Acid Combinations and Reaction Conditions

The Maillard reaction (MR), or non-enzymatic browning, involves reducing sugars reacting with amino acids, peptides, or proteins when heated to produce an abundance of products that contribute to sensory, nutritional, and functional qualities of the food system. One example of an important functional quality of MR relates to antioxidant capacity, which has relevance to preserve food quality and also to extend a potential role that may promote gastrointestinal health. The addition of Alphacel (10%), a non-reactive polysaccharide, to MR reactants produced small significant (p < 0.05) reductions in yield of soluble Maillard reaction products (MRPs), sugar loss, and color change of products formed respectively, for reducing sugars. A similar effect was also noticed for different free-radical scavenging capacity (p < 0.05), using chemical (e.g., 2,2-diphenyl-1-picrylhydrazyl (DPPH)), Trolox equivalent antioxidant capacity (TEAC), and oxygen radical absorbance capacity (ORAC) assays. An inflamed Caco-2 cell model revealed nitric oxide (NO) inhibitory activity for Glu-amino acid MRPs, which contrasted the NO stimulatory activity obtained with Fru-amino acid MRPs, especially when glycine was used as the amino acid. Pre-treating Caco-2 cells with Fru-glycine MRPs protected against loss in trans-epithelial resistance (TEER) (p < 0.05) and reduced (p < 0.05) disruption of Caco-2 intestinal epithelial tight-junction (TJ) protein cells when exposed to 7.5% ethanol. A low molecular weight Fru-glycine (e.g., <1 kDa) fraction contributed to the protective effect, not observed with the corresponding high molecular weight MRP fraction. The presence of Alphacel had minimal effect on generating MRPs with relative modified protection against intestinal dysfunction in cultured Caco-2 cells. Rather, different types of sugar-amino acid combinations used to generate MRPs contributed more to mitigate injury in stress-induced Caco-2 cells. With the growing evidence that MRPs have a wide range of bioactive activities, this study concludes that specificity of substrate precursors that produce MRPs in heated foods is a critical factor for antioxidant and related cellular functions that represent a healthy gut.