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.

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.

Using µX-Ray CT to observe postmortem diffusion from the stomach in a rat model.

The stomach has long been recognised as a depot for postmortem diffusion. A better understanding of the phenomena of postmortem diffusion would aid forensic practitioners in their interpretation of toxicological results. A limitation of previous stomach diffusion studies was the lack of ability to visualise postmortem diffusion in real time, the use of µX-ray Computed Tomography (CT) could overcome this problem. We utilised CT to track the diffusion of the contrast medium caesium ions (Cs+) (administered by oral gavage) from the rat stomach over 6 days. We investigated the influence of temperature (4°C and 20°C) and body position (horizontal and vertical). The results show that the a) diffusion of Cs+ from the stomach can be visualised over 6 days, over which a significant amount (∼50%) of the diffusion occurs in the first 24h following administration; b) storing the rat at 4°C reduces the distance of diffusion from the stomach by ∼66%; c) body position influences the route of diffusion and d) in 2 of the 16 rats studied Cs+ was found in the right lobe of the liver. Overall these results show that CT using Cs+ is a good model to visualise postmortem diffusion and that bodies show significant variation in postmortem diffusion. It is also clear that bodies should be refrigerated and postmortem samples should be taken as soon as possible to minimise the influences of postmortem diffusion from the stomach.

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'.

Visualisation of fingermarks and grab impressions on dark fabrics using silver vacuum metal deposition.

Vacuum metal deposition (VMD) involves the thermal evaporation of metal (silver) in a vacuum, resulting in a uniform layer being deposited on the specimen being treated. This paper examines the use of silver on dark fabrics, thus offering a simpler operation and more obvious colouration to that of the traditional use of gold and zinc metals which must be evaporated separately. The aim of this study was to investigate the effect of fabric type, donor, mark age and method of fingermark deposition on the quality of marks visualised using silver VMD. This was achieved by collecting fingermark deposits from fifteen donors, of both sexes and various ages, by a grab or a press method. Four different fabrics: satin, polyester, polycotton and cotton were studied over a 10day timeline of 1, 2, 3, 4, 5, 6, 7, 14, 21 and 28+ days. It was found that satin and polyester gave the most positive results, with polyester often producing excellent ridge detail. Cotton and polycotton were less successful with no ridge detail being observed. The donors also had an observable effect on the results obtained probably due to variations in secretions produced or pressures applied during specimen collection. The age of the mark or the method of mark deposition had little influence on the results obtained. Silver VMD is a viable process for visualising marks on certain dark fabrics and has the advantage over gold/zinc VMD in that the marks visualised are light in colour which contrasts well against the dark background.

Visualisation of fingermarks and grab impressions on fabrics. Part 1: gold/zinc vacuum metal deposition.

Vacuum metal deposition (VMD) is a highly sensitive technique originally introduced for detecting latent fingermarks on smooth non-porous surfaces such as carrier bags, plastics and glass. The current study explores whether VMD can be used in the examination of clothing from physical and sexual assault cases in order to visualise identifiable fingermark ridge detail and/or palmar flexion crease detail, thus allowing potential areas to be indicated for DNA swabbing and/or to determine the sequence of events. Four different fabrics were utilised during this study - nylon, polyester, polycotton and cotton, along with 15 donors who ranged in their age and propensity to leave fingermarks, from good to medium to poor as determined by results obtained from test runs using paper and plastic carrier bags processed with VMD. Once samples were collected they were kept for a determined time (1, 2, 3, 4, 5, 6, 7, 14, 21 or 28 days) and then treated using the gold/zinc metal VMD process. From the results, it appears that greater ridge detail is visible on the smoother non-porous fabrics, such as nylon whereas on rougher porous fabrics, such as cotton, only empty prints and impressions, rather than any ridge details, were visible. All fabrics did however allow the development of touch marks that could be targeted for DNA taping thus potentially leading to a DNA profile and possible identification of a suspect.