Limitation of Maillard Reactions in Lactose-Reduced UHT Milk via Enzymatic Conversion of Lactose into Galactooligosaccharides during Production

Flavor enhancement pathways and mechanisms of cold-pressed walnut oil based on defatted cold-pressed walnut meal hydrolysates

The present study aimed to investigate the effect and underlying mechanism of Maillard reaction products (MRPs) derived from defatted cold-pressed walnut meal hydrolysates (DCWMH) on the aroma enhancement of cold-pressed walnut oil (CWO). Nineteen key aroma-active compounds were identified in CWO, hot-pressed walnut oil (HWO), and flavored walnut oil (FWO) using gas chromatography-olfactory-mass spectrometry (GC-O-MS) and odor activity values (OAVs). Principal component analysis (PCA) based on quantitative descriptive analysis (QDA) showed that the "roasted flavor" was positively correlated with FWO. Correlation analysis of free amino acids identified aspartic acid (Asp) as a key aroma precursor. Additionally, a novel pathway for furfural formation via Schiff base intermediates was proposed from the free radical cleavage process of the Maillard reaction in the [13C5]Xylose-Asp model system. Overall, this study provides valuable insights into the control of flavor quality during walnut oil production and supports the potential for the comprehensive utilization of walnut by-products.

Investigation of Maillard reaction products in plant-based milk alternatives

Over the past decade, plant-based milk alternatives (PBMAs) have gained increasing popularity. Several processing technologies, including heat treatment, are usually employed during their production in order to replicate the properties of cow's milk. These processes can trigger the Maillard reaction, producing Maillard reaction products (MRPs) and amino acid cross-links, which may alter the nutritional profile and digestibility of PBMAs. This study investigates PBMAs available in the Scandinavian market to assess their MRP and amino acid cross-link concentrations, aiming to understand the relationship between the formation of these heat-induced compounds and the specific chemical composition of individual PBMAs. Two types of UHT-treated cow's milk and ten UHT-processed PBMAs from different brands were analyzed. Quantitative analyses included early-stage MRPs (Amadori products detected as furosine), intermediate MRPs (α-dicarbonyl compounds and furans), advanced glycation end products (AGEs), acrylamide, and amino acid cross-links (lanthionine and lysinoalanine). Protein, carbohydrate, and amino acid profiles were also assessed using LC-MS and HPLC methods. PBMAs were found to differ substantially in carbohydrate and protein content, with soy-based drinks containing higher protein and rice and oat drinks having more carbohydrates. Essential amino acid (EAA) levels were found lower in all PBMAs, impacting their nutritional quality. MRP levels, such as furosine and AGEs, varied across PBMAs, indicating different heat-processing intensities. Specific α-dicarbonyl compounds, like 3-deoxyglucosone, were more concentrated in PBMAs than in UHT-treated cow's milk, and compounds like HMF, furfural, and acrylamide were also found in some PBMAs. Finally, correlations were observed between sugar content, α-dicarbonyls, and AGEs, which offer insights into possible chemical transformations in PBMAs during processing.

Effects of different reducing carbohydrate types on the physicochemical characteristics of infant formula food stored for special medical purposes

The formula of food for special medical purpose has a direct impact on physicochemical stability, especially in hot climes and high temperature transport storage environments. An accelerated test (50 °C for 7 weeks) was used to analyze the mechanism of the physicochemical instability of formula A with lactose and maltodextrin, and formula B with maltodextrin. Deep dents and wrinkles were observed on the surface of the formula B, and more fat globules covered the surface of formula A particles after storage for a long time. Significantly higher amounts of furosine and Nε-carboxymethl-l-lysine (CML) were formed and the loss of available lysine was greater in formula A than in formula B. No significant difference was observed in lipid oxidation indicators between the two formulas. The results of this research demonstrated lactose was more active than maltodextrin and led to physicochemical instability.

Galactooligosaccharides in infant formulas: Maillard reaction characteristics and influence on formation of advanced glycation end products

As prebiotics supplemented in infant formulas (IFs), galactooligosaccharides (GOSs) also have many other biological activities; however, their Maillard reaction characteristics are still unclear. We investigated the Maillard reactivity of GOSs and their effects on advanced glycation end product (AGE) formation during IF processing. The results showed that AGE and HMF formation was temperature-dependent and reached the maximum at pH 9.0 in the Maillard reaction system of GOSs and Nα-acetyl-L-lysine. Acidic conditions accelerated HMF formation; however, protein cross-linking was more likely to occur under alkaline conditions. The degree of polymerization (DP) of GOSs had no significant effect on AGEs formation (except pyrraline); however, the greater the DP, the higher the concentration of HMF and pyrraline. Besides, compared with arginine and casein, lysine and whey protein were more prone to Maillard reaction with GOSs. GOSs promoted AGEs formation in a dose-dependent manner during the processing of IFs. These results provide a reliable theoretical basis for application of GOSs in IFs.

Evaluation of Fructo-, Inulin-, and Galacto-Oligosaccharides on the Maillard Reaction Products in Model Systems with Whey Protein

The present study aimed to investigate the effects of fructo-, inulin-, and galacto-oligosaccharides (FOS, IOS, and GOS) on forming the Maillard reaction products such as browning, α-dicarbonyl compounds, and advanced glycation end products (AGEs). The model solutions at pH 6.8 containing each carbohydrate (mono-, di-, and oligosaccharides) and whey protein were incubated at 50 °C for 8 weeks. In the IOS model, sugars of DP3 or larger were significantly decreased at 4 weeks, whereas at 6 weeks in the FOS model. The residual amount of GOS after 8 weeks was higher than FOS and IOS; however, a large amount of 3-deoxyglucosone was formed compared to the other models. N^ε-Carboxymethyllysine (CML) concentrations in oligosaccharide models were about half of those in monosaccharide and lactose models. The highest concentrations of glyoxal- and methylglyoxal-derived hydroimidazolones 3 (G-H3 and MG-H3) were observed in the IOS model, indicating the involvement of fructose units linked by β-2 → 1 bonds. G-H3 and MG-H3 quantification could be a useful indicator to reflect the modification of an arginine residue by fructose if used acid-hydrolysis for AGE analysis. CML, G-H3, and MG-H3 were considerably formed even in the FOS model, which has no reducing terminal site, suggesting that degradation products of oligosaccharides probably participated in the formation of AGEs.

Quality indicators in lactose hydrolyzed milks and soy beverages from Colombia

Worldwide there is great interest in producing low lactose milk and drinks, such as soy beverages, suitable for consumption by lactose-intolerant people. These products have different carbohydrate compositions, which affect quality indicators derived from Maillard reaction (furosine and 5-hydroxyl-methyl furfural, HMF). In this study, quality parameters have been determined in 11 commercial samples (8 lactose-hydrolyzed milks and 3 soy beverages). Presence of β-galactooligosaccharides in milks (22.2-458.1 mg/100 mL) correlating roughly with the remaining lactose content (1.9-357.7 mg/100 mL). Soy beverages contained α-galactosides in concentrations of 30-75 mg/100 mL. HMF and furosine were detected in all milk samples. In addition, powdered milks subjected to controlled storage (40 °C, a_w 0.44) showed a furosine increase up to 88%. In conclusion, a great composition diversity was observed in the different products, probably favored by the lack of regulation and underline the importance of controlling processing and storage conditions to preserve product quality.

Maillard reaction harmful products in dairy products: Formation, occurrence, analysis, and mitigation strategies

Various harmful Maillard reaction products such as lactulosyl-lysine (furosine), furfurals, and advanced glycation end products (AGEs) could be formed during the thermal processing of dairy products, which could lead to various chronic diseases. In this review, the furosine, furfurals, and AGEs formation, occurrence, analysis methods, and toxicological and health aspects in various dairy products were summarized to better monitor and control the levels of harmful Maillard reaction products in processed dairy products. It was observed that all types of dairy products, including raw milk, contain harmful Maillard reaction products, with the highest in whey cheese and condensed milk. High-performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) is the common method for the determination of furosine and furfurals and AGEs in dairy products, respectively. However, the simple, rapid, environment-friendly, and accurate methods of determination are still to be developed. Incorporating resveratrol, pectin oligosaccharides (POS) in milk are effective methods to inhibit AGEs formation. This review provides a guide not only for consumers regarding the selection and consumption of dairy products, but also for monitoring and controlling the quality of dairy products.