Molecular interactions of milk protein with phenolic components in oat-based liquid formulations following UHT treatment and prolonged storage

Interactions between proteins and phenolics: effects of food processing on the content and digestibility of phenolic compounds

Phenolic compounds have recently become one of the most interesting topics in different research areas, especially in food science and nutrition due to their health-promoting effects. Phenolic compounds are found together with macronutrients and micronutrients in foods and within several food systems. The coexistence of phenolics and other food components can lead to their interaction resulting in complex formation. This review article aims to cover the effects of thermal and non-thermal processing techniques on the protein-phenolic interaction especially focusing on the content and digestibility of phenolics by discussing recently published research articles. It is clear that the processing conditions and individual properties of phenolics and proteins are the most effective factors in the final content and intestinal fates of phenolic compounds. Besides, thermal and non-thermal treatments, such as high-pressure processing, pulsed electric field, cold plasma, ultrasonication, and fermentation may induce alterations  in those interactions. Still, new investigations are required for different food processing treatments by using a wide range of food products to enlighten new functional and healthier food product design, to provide the optimized processing conditions of foods for obtaining better quality, higher nutritional properties, and health benefits. © 2024 Society of Chemical Industry.

Covalent polyphenols-proteins interactions in food processing: formation mechanisms, quantification methods, bioactive effects, and applications

Proteins and polyphenols are abundant in the daily diet of humans and their interactions influence, among other things, the texture, flavor, and bioaccessibility of food. There are two types of interactions between them: non-covalent interactions and covalent interactions, the latter being irreversible and more powerful. In this review, we systematically summarized advances in the investigation of possible mechanism underlying covalent polyphenols-proteins interaction in food processing, effect of different processing methods on covalent interaction, methods for characterizing covalent complexes, and impacts of covalent interactions on protein structure, function and nutritional value, as well as potential bioavailability of polyphenols. In terms of health promotion of the prepared covalent complexes, health effects such as antioxidant, hypoglycemic, regulation of intestinal microbiota and regulation of allergic reactions have been summarized. Also, the possible applications in food industry, especially as foaming agents, emulsifiers and nanomaterials have also been discussed. In order to offer directions for novel research on their interactions in food systems, nutritional value, and health properties in vivo, we considered the present challenges and future perspectives of the topic.

Heat Treatment of Milk: A Rapid Review of the Impacts on Postprandial Protein and Lipid Kinetics in Human Adults

Background: Most milk consumed by humans undergoes heat treatment to ensure microbiological safety and extend shelf life. Although heat treatment impacts the structure and physiochemical properties of milk, effects on nutrient absorption in humans are unclear. Therefore, a rapid review was performed to identify studies conducted on healthy human adult subjects that have assessed the impacts of heat treatment of milk on protein and fat digestion and metabolism in the postprandial period (up to 24 h). Methods: Relevant databases (Medline, EMBASE, Cochrane, Scopus) were systematically screened for intervention studies on healthy adult men and women that assessed the impact of consuming heat-treated milk on the postprandial kinetics or appearance in peripheral circulation or urine of ingested proteins and/or lipids. The risk-of-bias assessment tool 2 was used for quality assessment. Results: Of 511 unique database records, 4 studies were included encompassing 6 study treatments (n = 57 participants, 20-68 years). Three studies evaluated pasteurization, two evaluated ultra-high temperature (UHT) treatment, and one evaluated oven-heated milk. Protein and lipid appearances in peripheral blood were reported in two sets of two studies. None of the studies used the same heat treatments and outcome measures, limiting generalization of effects. Protein appearance (ng/mL or area under the curve) (as plasma amino acids - lysine) was reduced when milk was oven-heated for 5 h in one study (n = 7 participants), while the other study reported a reduced retention of dietary N with UHT milk (n = 25 participants). Overall plasma triacylglycerol responses were unaffected by milk heat treatments reported, but plasma fatty acid composition differed. The studies observed higher plasma myristic and palmitic acid abundance with successive heat treatment at 2 h (n = 11 participants; pasteurized) and 4 h (n = 14 participants; UHT) after ingestion; other differences were inconsistent. All studies had moderate-high risk of bias, which should be taken into consideration when interpreting findings. Discussion: This review identified few studies reporting the effects of milk heat treatment on postprandial nutrient responses in adults. Although the findings suggest that milk heat treatment likely affects postprandial protein and lipid dynamics, generalization of the findings is limited as treatments, outcomes, and methods differed across studies. Because of the study variability, and the acute post-prandial nature of the studies, it is also difficult to draw conclusions regarding potential long-term health outcomes. However, the possibility that altered digestive kinetics may influence postprandial protein retention and anabolic use of dietary N suggests heat treatment of milk may impact outcomes such as long-term maintenance of muscle mass.

Influence of Processing Conditions on the Physicochemical Properties of a New-Type of Nutritional Drink-Millet Skim Milk Beverage

In this experiment, a new type of nutritional drink—millet skim milk beverage—was developed based on combining skim milk with millet and nutritional resource utilization. The effects of NaHCO₃ concentrations in soaking water (0, 0.5 g/100 mL, and 1.0 g/100 mL) and blanching time (0, 15, and 30 min) on the physicochemical properties of millet skim milk were studied. The parameter changes caused by the above treatment were evaluated via color analysis, physicochemical analysis and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Soaking in water containing NaHCO₃ had a significant (p < 0.05) effect on pH, specific gravity, viscosity, and stability. The blanching treatment had a significant (p < 0.05) influence on the total solids of the samples. However, blanching only slightly affected the physical properties of the samples. In addition, soaking and blanching treatments had significant (p < 0.05) effects on the b* value of millet skim milk beverage, whereas there was no significant (p > 0.05) change in L* and a*. SDS-PAGE analysis indicated that the blanching treatment had a significant (p < 0.05) effect on band 5 and band 6 and that the soaking treatment also had a significant effect on the bands of 6 and 7 (p < 0.05). By analyzing the substantial effects, we concluded that the optimum process conditions were soaking with 0.5 g/100 mL NaHCO₃ solution and blanching for 15 min.