A new physical and biological strategy to reduce the content of zearalenone in infected wheat kernels: the effect of cold needle perforation, microorganisms, and purified enzyme.

With the aim of reintroducing wheat grains naturally contaminated with mycotoxins into the food value chain, a decontamination strategy was developed in this study. For this purpose, in a first step, the whole wheat kernels were pre-treated using cold needle perforation. The pore size was evaluated by scanning electron microscopy and the accessibility of enzymes and microorganisms determined using fluorescent markers in the size range of enzymes (5 nm) and microorganisms (10 µm), and fluorescent microscopy. The perforated wheat grains, as well as non-perforated grains as controls, were then incubated with selected microorganisms (Bacillus megaterium Myk145 and B. licheniformis MA572) or with the enzyme ZHD518. The two bacilli strains were not able to significantly reduce the amount of zearalenone (ZEA), neither in the perforated nor in the non-perforated wheat kernels in comparison with the controls. In contrast, the enzyme ZHD518 significantly reduced the initial concentration of ZEA in the perforated and non-perforated wheat kernels in comparison with controls. Moreover, in vitro incubation of ZHD518 with ZEA showed the presence of two non-estrogenic degradation products of ZEA: hydrolysed zearalenone (HZEA) and decarboxylated hydrolysed ZEA (DHZEA). In addition, the physical pre-treatment led to a reduction in detectable mycotoxin contents in a subset of samples. Overall, this study emphasizes the promising potential of combining physical pre-treatment approaches with biological decontamination solutions in order to address the associated problem of mycotoxin contamination and food waste reduction.

Influence of Aerobic and Anaerobic Moist Incubation on Selected Nonvolatile Constituents─Comparison to Traditionally Fermented Cocoa Beans.

Recently, moist incubation has been proposed as an alternative postharvest processing method for cocoa beans. During this treatment, unfermented and dried cocoa nibs are rehydrated with a lactic acid solution containing ethanol and subsequently incubated for 72 h at 45 °C before drying. Previous studies focused on the aroma formation during this treatment and the further processing of chocolate. The current study focused on the influence of aerobic and anaerobic moist incubation on selected nonvolatile components in comparison with the unfermented raw material and traditionally fermented cocoa. Total phenolic content and total flavan-3-ol content, contents of (+)-catechin, (-)-epicatechin, procyanidins B2 and C1, cinnamtannin A2, methylxanthines (theobromine and caffeine), contents of sugars (sucrose, d-glucose, and d-fructose) and free amino acids (17 proteinogenic amino acids) were determined. The fermentation index was also evaluated. The aerobically incubated and fermented cocoa showed low levels of phenolic compounds in comparison to the unfermented cocoa and the anaerobically incubated cocoa. The level of methylxanthines was unaffected by all treatments. The contents of reducing sugars were more than 2-fold higher after both incubation treatments compared to fermentation. The level of free amino acids liberated was highest after anaerobic incubation followed by fermentation and aerobic incubation. The aerobically incubated cocoa showed the highest FI, while the anaerobically incubated cocoa may be considered under-fermented (FI <1.0). Statistical analysis (ANOVA) showed significant differences between all treatments, which was verified by principal component analysis.

Use of molecular networking to identify 2,5-diketopiperazines in chocolates as potential markers of bean variety.

2,5-diketopiperazines are cyclic dipeptides found, among others, in chocolate. Although those compounds are contributing greatly to its pleasant bitterness, they can also be seen as interesting markers of cocoa beans processing. To evaluate the influence of bean variety and processing technology on the quantity of 2,5-diketopiperazines formed in chocolates, HPLC-MS/MS analyses were conducted, and a molecular network was built with the MS2 data. This approach eases the identification of 2,5-diketopiperazines within complex datasets and allows to visualize the chemical diversity of all samples. Using this methodology, 33 dark chocolates were analysed. 18 different diketopiperazine were identified and quantified. Among them, cyclo(L-ile-L-val), cyclo(L-leu-L-ile) and cyclo(L-phe-L-phe) were, to the best of our knowledge, detected for the first time in chocolate. The molecular network allows the clear visualization of differences between samples. The principal component analysis revealed the clustering of small batch chocolate samples according to bean variety, suggesting that bean genotype has a strong influence on the 2,5-diketopiperazines content of bean-to-bar chocolates, regardless of the degree of roasting or the technological process used by the small producers. The presence of two unique diastereoisomers in the classical chocolates bought in the supermarket indicates that the beans have probably undergone a more intense heat treatment. This study proposes the use of 2,5-diketopiperazines as potential markers of cocoa beans variety, as well as an indicator of post-harvest processing and processing technology, and highlights the potential of the molecular networks in the field of food and drink innovation as a promising tool to understand the complex chemistry of flavours.

Decoding the Fine Flavor Properties of Dark Chocolates.

Fine flavor properties of chocolates such as fruity, floral, and cocoa-like were decoded on a molecular level for the first time. The molecular compositions of six chocolates made out of liquors that were referenced with specific sensory attributes were analyzed. After the screening for odor-active molecules by aroma extract dilution analysis, selected compounds were quantitated with the overall aim to decode the distinct fine flavor attributes on a molecular level. Acidic and fruity flavor notes were associated with high dose over threshold factors (DoT factors) of acetic acid and fruity smelling esters such as ethyl 2-methylbutanaote, ethyl 3-methylbutanoate, and 3-methylbutyl acetate, respectively. Cocoa-like and roasty flavor notes were associated with high DoT factors for 2-methylbutanal, 3-methylbutanal, 4-hydroxy-2,5-dimethylfuran-3(2H)-one, and dimethyltrisulfane. The floral and astringent flavors were linked to high DoT factors of (-)-epicatechin, procyanidin B2, procyanidin C1, and 2-phenylethan-1-ol.

Evolution of the Polyphenol and Terpene Content, Antioxidant Activity and Plant Morphology of Eight Different Fiber-Type Cultivars of Cannabis Sativa L. Cultivated at Three Sowing Densities.

The chemical composition of the inflorescences of eight different fibre-type Cannabis sativa L. cultivars grown in Switzerland was monitored for different sowing densities over the season 2019. HPLC-MS, GC-MS and GC-FID, as well as spectrophotometric techniques were used to measure the total phenolic content (TPC) and the antioxidative activity of the inflorescence extracts, and to characterise and quantify the flavonoids and terpenes produced by the different cultivars over different sowing densities from July to September 2019. The main finding of the present study is that the TPC, as well as the individual flavonoids and terpenes, were mainly influenced by the harvest period and the phenological stage of the plant. The content of polyphenols and flavonoids decrease during the flower development for all cultivars studied. The terpene content increased with maturation. The monoterpenes/sesquiterpenes ratio also changed between the early flowering (majority of sesquiterpenes) and the end of flowering (majority of monoterpenes). The sowing density showed an impact on plant morphology, a low density such as 30 seeds/m2 influencing the production of bigger flowers, thus increasing the yield of polyphenols and terpenes production. Therefore, hemp inflorescences can be regarded as valuable by-products of fibre production, for their valorisation in the food and beverage industry in addition to cosmetics and perfumery.

Potent and Non-Cytotoxic Antibacterial Compounds Against Methicillin-Resistant Staphylococcus aureus Isolated from Psiloxylon mauritianum, A Medicinal Plant from Reunion Island.

With the occurrence of antibiotic-resistant Staphylococcus aureus strains, identification of new anti-staphylococcal drugs has become a necessity. It has long been demonstrated that plants are a large and diverse source of antibacterial compounds. Psiloxylon mauritianum, an endemic medicinal plant from Reunion Island, was chemically investigated for its reported biological activity against S. aureus. Aspidin VB, a phloroglucinol derivative never before described, together with Aspidin BB, were first isolated from the ethyl acetate extract of P. mauritianum leaves. Their structures were elucidated from spectroscopic data. Aspidin VB exhibited strong antibacterial activity against standard and methicillin-resistant S. aureus strains, with a minimal inhibition concentration (MIC) of 0.25 µg/mL, and no cytotoxicity was observed at 10-5 M in MRC5 cells. Due to its biological activities, Aspidin VB appears to be a good natural lead in the fight against S. aureus.

A method to quantify intracellular glycation in dermal fibroblasts using liquid chromatography coupled to fluorescence detection - Application to the selection of deglycation compounds of dermatological interest.

Glycation is a common non-enzymatic reaction between proteins and sugars, which gives rise in the human body to the formation of advanced glycation end products (AGEs). These modifications impacts both extra and intracellular proteins, leading to cells and tissues dysfunctions. In the skin, accumulation of AGEs leads to aesthetic consequences, wrinkles, dark spots and yellowish skin tone, as it can be seen in diabetic patients. Consequently, there is a growing dermatological interest to find compounds able to eliminate AGEs accumulated in skin. In this context, a method has been developed to detect and quantify intracellular glycation in human dermal fibroblasts. After cultivation of fibroblasts, cell lysates were injected in an HPLC system coupled with a fluorescence detector in by-pass mode. The system allows the simultaneous measurement of global AGEs and particular pentosidine amounts using two sets of wavelengths in a single run of 1 min. The immunocytochemistry approach was used to valid the HPLC analysis data. The method developed was able to quantify changes in global AGEs and pentosidine content in cells in response to glyoxal treatment. Fibroblasts treated with 500 µM of glyoxal for 48 h showed a significant 2.3-fold and 2.6-fold increase in the content of AGEs and pentosidine respectively compared to control cells. As an application, a screening of natural extracts have been done and the method allowed identifying extracts able to significantly reduce the amount of pentosidine in fibroblasts (-32%). These extracts act as deglycation agents of interest in the field of dermatology and cosmetology.