Interaction of milk whey protein with common phenolic acids

Incorporating salal berry (Gaultheria shallon) and blackcurrant (Ribes nigrum) pomace in yogurt for the development of a beverage with antidiabetic properties

In this study aqueous extracts from salal berry (SB) and blackcurrant pomace (BCP) were used to reformulate yogurt and the anti-diabetic properties of the beverage were investigated during 4 weeks of cold storage at 4 °C. Results indicated that α-amylase, α-glucosidase and DPP-IV inhibitory activities increased with storage time for all samples. At the end of storage period α-amylase, α-glucosidase and DPP-IV inhibition were >61%, 62% and 56% respectively for all yogurt types. This increase in bioactivity during cold storage is attributed to the viability of lactic acid bacteria (∼108 cfu/g), which is maintained for 4 weeks. Enzyme inhibition increased similarly for all yogurt types at 4 °C except for α-glucosidase. Yogurt with BCP showed the highest potency to inhibit α-glucosidase (>90%) with an IC50 value of 0.20 mg/ml (week 4). A peptidomic approach based on liquid chromatography coupled with mass spectrometry (LC-MS) was used for the separation and identification of peptides generated in three types of yogurt. A total of 486 peptides mainly from caseins were identified, of which 15 have documented bioactivity, predominantly as antimicrobial agents or ACE-inhibitors.

The effect of dietary factors on strawberry anthocyanins oral bioavailability

Strawberries are a dietary source of anthocyanins, particularly pelargonidin glycosides. Dietary anthocyanins have received increasing attention among researchers and consumers due to their health benefits. The oral bioavailability of anthocyanins is reported to be low and various dietary factors may influence their oral bioavailability further. Milk is suggested to reduce (poly)phenols' oral bioavailability. However, the effect of milk on anthocyanin oral bioavailability remains uncertain. Likewise, mixed nutrient meals may influence the oral bioavailability of anthocyanins. Therefore, the purpose of this study was to assess the effect of milk on the oral bioavailability and other pharmacokinetic (PK) variables of strawberry anthocyanins consumed with and without a meal. Nine healthy participants consumed a strawberry beverage prepared in milk or water with a standard meal on two occasions. On two additional occasions, the beverages were given to a subset (n = 4) of participants to determine the impact of the meal on anthocyanin PK variables, including oral bioavailability. Independent of the meal, beverages prepared in milk significantly reduced the peak plasma concentrations (C_max) of pelargonidin-3-O-glucoside (P-3-G), pelargonidin-glucuronide (PG) and pelargonidin-3-O-rutinoside (P-3-R), as well as the PG and P-3-R area under the curve (AUC) (p < 0.05) compared to beverages prepared in water. Milk did not influence the oral relative bioavailability of pelargonidin anthocyanins under meal conditions; however, the oral relative bioavailability of pelargonidin anthocyanins was reduced by ∼50% by milk under without meal conditions (p < 0.05). Consuming strawberry beverages made with milk and consuming those made with water with and without a meal influenced different aspects of strawberry anthocyanin PKs. The significance of this effect on clinical efficacy requires additional research.

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

BACKGROUND

Nowadays there is a growing demand for nutritionally balanced breakfast beverages enriched with functional ingredients including wholegrain oat, which is rich in phenolic acids. Such beverages typically contain added food ingredients (e.g. milk protein, sugar and lipids) and undergo thermal processing that initiates many molecular processes. Therefore, this work aims to investigate the molecular interactions between milk protein and phenolic acids that govern bioactivity in model oat-based beverages.

RESULTS

Findings showed the susceptibility of ferulic and p-coumaric acids, in model oat beverages, to ultra-high temperature (UHT) processing at 145 °C for 8 s. Among model beverages, those with added milk protein demonstrated a considerable loss of phenolic acids following UHT processing due to the interaction between these micronutrients and the protein. The nature of molecular interactions was mainly categorized as covalent with hydrogen bonds playing a supportive role.

CONCLUSION

UHT processing of oat-based beverage formulations facilitates the formation of protein-phenolic acid complexes, which are largely covalent and static in nature. This finding underlines the ability of UHT treatment to induce chemical modifications of food ingredients. © 2017 Society of Chemical Industry.

Investigating the affinity of BDE154 and 3OH-BDE154 with HSA: Experimental and simulation validation

The physicochemical properties of polybrominated diphenyl ethers are important for modeling their transport, but these data are often missing. Here, satisfactory bioactivity results were obtained using human serum albumin as the carrier, 2,2',4,4',5,6'-hexabromodiphenyl ether (BDE154) and 3-hydroxy-2,2',4,4', 5,6'-hexabromodiphenyl ether (3OH-BDE154) as the ligands, using UV-visible absorbance, fluorescence, circular dichroism, molecular docking, and molecular dynamics methods. The interactions between human serum albumin and BDE154 or 3OH-BDE154 were verified, consistent with the static quenching procedure. At pH 7.4, the binding constants of the complexes for site I were relatively comparable and increased in the order BDE154<3OH-BDE154. Then, the secondary structure and kinetic parameters of albumin were analyzed using the circular dichroism spectra and GROMACS software. The data obtained from these simulations indicate that hydrophobic attraction might be the key factor for the stability of complexes. The docking experiments provided further insight into the hydrophobic pocket and showed that 3OH-BDE154 has a stronger binding affinity to human serum albumin than BDE154. The experimental spectral data were obtained and compared with the simulation results, showing good agreement. A detailed analysis of PBDEs-HSA interactions would provide valuable information to better understand the interaction on this class of compounds.