Effect of brewer's spent grain melanoidins on maillard reaction products during storage of whey protein model systems.

Maillard reaction readily takes place in dairy products because of the association between thermal treatments, extended storage and the matrix composition. Along with the impairment of protein digestion, the formation of glycation and α-dicarbonyl compounds is a concern for quality attributes of whey proteins when used as ingredients. In this paper, we outline the capacity of brewer's spent grain melanoidins in reducing the accumulation of α-dicarbonyl compounds, thus controlling the formation of dietary advanced glycation end-products in accelerated shelf life at 35 °C. Results revealed that brewer's spent grain melanoidins targeted methylglyoxal and glyoxal reactivity leading to the reduction of N-ε-carboxymethyllysine and methylglyoxal-hydroimidazolone up to 27 and 60%, respectively. We here describe that the presence of melanoidins is instrumental in limiting the undesired effects of α-dicarbonyl compounds on whey proteins.

Long-Time Evaluation of Solid-State Composite Reference Electrodes.

In this study, the performance and long-time evaluation of solid-state composite (SSC) reference electrodes were investigated. The stability of all the SSC reference electrodes was continuously monitored by using potentiometry and electrochemical impedance spectroscopy methods over a period of several months. A multi-solution protocol was used to study the influence of the ionic strength of the sample solution, ion charge, and mobility, and the sample pH values on the performance of the reference electrodes. The SSC reference electrodes were used in the calibration of commercial indicator electrodes for different ions at different temperatures. The concentrations of K+, Na+, Ca2+, and Cl- ions and pH values were measured in river water samples at different temperatures using the SSC reference electrodes. The obtained results for the same samples were compared with the results given by an independent laboratory specialized in routine water analyses. The agreement between the results was very good and even better than the case where commercial reference electrodes were used. Our study showed that the SSC reference electrodes exhibit good long-term stability and excellent performance, both in the calibrations and analyses of environmental samples.

Effect of novel sequential soaking treatments on Maillard reaction products in potato and alternative vegetable crisps.

Frying leads to the formation of numerous food contaminants through the Maillard reaction (MR). In this paper, commercially available vegetable crisps were analysed for and established to have high levels of acrylamide. Consequentially, the capability of two novel sequential pre-frying treatments were applied to potato, beetroot and parsnip snacks to inhibit the formation of acrylamide, 5-hydroxymethylfurfural (HMF), glyoxal (GO) and methylglyoxal (MGO) was investigated. Data revealed that immersion in cold tap water for 2 min followed by blanching at 70 ± 2 °C for 2 min (Cold soak, hot soak, (CSHS)) as well as soaking in a 0.01M CaCl2 solution for 2 min followed by blanching at 70 ± 2 °C in 0.1M citric acid for 2 min were both effective pre-treatments for potato crisps, simultaneously decreasing acrylamide concentration under the benchmark level of 750 µg/kg and lowering GO content by 55.19 and 54.67% and MGO concentration by 39.17% and 81.62%, respectively. CSHS was the only efficient treatment for concurrent mitigation of acrylamide (-41.64%) and HMF (-88.43%) with little GO and MGO development in beetroot. Sequential cold soak in 0.01M calcium chloride and hot soak in a 0.1M citric acid solution has been effective in decreasing acrylamide in alternative crisps. However, this led to an increase in HMF, 30 and 20-fold respectively from the initial concentration. Data reveal that the tested mitigation strategies are vegetable specific.

Evaluation of the effect of berry extracts on carboxymethyllysine and lysine in ultra-high temperature treated milk.

Both the Maillard reaction (MR) and thermal treatment influence the nutritional value of milk. In this paper, the capability of polyphenolic berry extract (PBE) to inhibit MR in an ultra-high temperature (UHT) treated milk was investigated. Total polyphenol content and antioxidant capacity of blueberry (BE) and raspberry extracts (RE) were also tested. A gas chromatography-mass spectrometry (GC-MS) method was developed to monitor the MR product N ε-(carboxymethyl)-L-lysine (CML) and L-lysine (LYS). PBE was added to milk at 0.05 and 0.1% w/v prior to UHT processing. Data revealed that formation of CML was significantly reduced (23.4 ± 5.1%) by addition of 0.1% w/v BE. The final concentrations of LYS measured following the addition of PBE prior to thermal treatment were statistically similar to the control milk which was not subjected to thermal processing. Additionally, the metabolic profile of milk samples was investigated by GC-MS and visualised using 'FancyTiles'.

Encapsulation of Olive Leaves Extracts in Biodegradable PLA Nanoparticles for Use in Cosmetic Formulation.

The aim of the current work was to encapsulate olive leaves extract in biodegradable poly(lactic acid) nanoparticles, characterize the nanoparticles and define the experimental parameters that affect the encapsulation procedure. Moreover, the loaded nanoparticles were incorporated in a cosmetic formulation and the stability of the formulation was studied for a three-month period of study. Poly(lactic acid) nanoparticles were prepared by the nanoprecipitation method. Characterization of the nanoparticles was performed using a variety of techniques: size, polydispersity index and ζ-potential were measured by Dynamic Light Scattering; morphology was studied using Scanning Electron Microscopy; thermal properties were investigated using Differential Scanning Calorimetry; whereas FT-IR spectroscopy provided a better insight on the encapsulation of the extract. Encapsulation Efficiency was determined indirectly, using UV-Vis spectroscopy. The loaded nanoparticles exhibited anionic ζ-potential, a mean particle size of 246.3 ± 5.3 nm (Pdi: 0.21 ± 0.01) and equal to 49.2%, while olive leaves extract release from the nanoparticles was found to present a burst effect at the first 2 hours. Furthermore, the stability studies of the loaded nanoparticles' cosmetic formulation showed increased stability compared to the pure extract, in respect to viscosity, pH, organoleptic characteristics, emulsions phases and grid.