Holistic Lipidomics of the Human Gut Phenotype Using Validated Ultra-High-Performance Liquid Chromatography Coupled to Hybrid Orbitrap Mass Spectrometry.

As lipids are assigned a plethora of biological functions, it is evident that dysregulated lipid metabolism signifies a key element in many pathological conditions. With this rationale, this study presents a validated lipidomics platform to map the fecal lipidome, which integrates unique information about host-gut microbiome interactions, gastrointestinal functionality, and dietary patterns. This particular method accomplished coverage across all eight lipid categories: fatty acyls, glycerolipids, phosphoglycerolipids, polyketides, prenols, saccharolipids, sphingolipids, and sterols. Generic extraction of freeze-dried feces was achieved by solid-liquid extraction using methanol and methyl tert-butyl ether. Extracted components were separated by liquid chromatography, whereby the selected ethylene-bridged hybrid phenyl ultra-high-performance liquid chromatography stationary phase allowed fast separation of both individual lipid species and categories. Detection was achieved by high-resolution full-scan Q-Exactive Orbitrap mass spectrometry and covered a broad m/z scan range (67-2300 Da). Method validation was performed in a targeted fashion to evaluate the analytical performance across all lipid categories, revealing excellent linearity (R2 ≥ 0.9921), acceptable repeatability (coefficients of variance ≤15.6%), and stable recovery (coefficients of variance ≤11.9%). Method suitability for untargeted fingerprinting was verified, demonstrating adequate linearity (R2 ≥ 0.90) for 75.3% and acceptable repeatability (coefficients of variance ≤30%) for 84.5% of about 9000 endogenous fecal compounds. Eventually, the potential of fecal lipidomics was exemplified within a clinical context of type 2 diabetes, thereby revealing significant perturbations [orthogonal partial least-squares discriminant analysis Q2(Y) of 0.728] in the fecal lipidome between participants with normal blood glucose levels (n = 26) and those with type 2 diabetes (n = 17).

Molecular detection of Spiroplasma apis and Spiroplasma melliferum in bees.

Spiroplasma apis and Spiroplasma melliferum are known as honey bee pathogens and are detected by unspecific methodologies like culturing or dark field microscopy. We developed a multiplex PCR being able to differentiate between both species and detect the genus Spiroplasma. This PCR can directly be used on culture samples or on DNA extracted bees. By PCR on cultured samples we were able to identify S. apis in Bombus pratorum and S. melliferum in Bombus pascuorum.

Sensory evaluation of boar meat products by trained experts.

Rearing entire male pigs, one of the alternatives for surgical castration, entails the possible occurrence of boar taint. This study aimed at the investigation of the acceptability of meat from entire male pigs in 8 different meat products (cutlets, bacon, blade loin, tenderloin, dry fermented sausage, cooked ham, dry-cured ham and minced meat) by trained assessors. Generally, the sensory evaluation of meat samples was affected the most in the androstenone (AEON) group, indicating that AEON is the most offensive boar taint compound for sensitive assessors. Differences between the meat products showed the highest potential for processing tainted meat in cold meat products, which was most likely due to the serving temperature on the one hand and production-related influences on the other. However, more insights regarding reducing and masking effects of production-related factors on boar taint are necessary.

Sensory evaluation of boar-taint-containing minced meat, dry-cured ham and dry fermented sausage by a trained expert panel and consumers.

One of the main issues related to entire male pigs is the occurrence of boar taint, an off-odour, which compromises meat consumability. In this study, odour thresholds (indole: 24-65µgkg-1, skatole: 44-89µgkg-1, androstenone: 121-342µgkg-1) for the boar taint compounds were estimated in minced meat, dry fermented sausage and dry-cured ham. Afterwards, sensory evaluation of these products containing 10% tainted meat (minced meat and dry fermented sausage) or moderate boar taint compound levels (dry-cured ham) occurred. The beneficial effect of diluting tainted meat was demonstrated, as no significant difference in consumability was observed between gilts and 10% tainted meat by experts as well as consumers. Also dry-curing proved a promising technique for masking boar taint and preventing consumer dissatisfaction. The obtained results demonstrate the applicability of the estimated thresholds in meat as a tool for identifying masking and reducing strategies on the perception of boar taint.

Boar taint compound levels in back fat versus meat products: Do they correlate?

Surgical castration of male pigs will soon be abandoned, turning a major advantage of this practice, the elimination of boar taint, into the biggest challenge for pig industry when raising intact male pigs becomes common practice. To map the (economical) consequences in relation to boar-taint consumer acceptance, as well as offer a processing strategy for tainted carcasses to stockholders, the current study investigated not only back fat boar taint levels, but additionally generated information on the levels of boar taint compounds recovered after the production of commercially relevant meat products using UHPLC-HRMS laboratory analysis. Our results demonstrate that levels of androstenone, skatole and indole in back fat and meat products tend to correlate strongly, particularly in fatty meat products (generally r>0.80). Concentration values in the edible (lean) meat fraction were significantly lower compared to back fat and fat sampled from fresh or processed meat (p<0.05).

Development and validation of a UHPLC-HR-Orbitrap-MS method for the simultaneous determination of androstenone, skatole and indole in porcine meat and meat products.

Boar taint is an off-odour that entails negative consumer reactions. In this study two extraction and UHPLC-HRMS analysis methods, valuable for evaluation of consumer acceptance towards boar meat, were developed for quantification of indole, skatole, and androstenone in different meat products. Sample pretreatment consisted of extraction with methanol and a homogenising step (cooked ham, minced meat, tenderloin, bacon, cutlets, blade loin, uncooked ham) or a melting step (salami sausage and liver paste). Both methods were validated according to CD 2002/657/EC and ISO 17025 guidelines. Good performance characteristics were obtained. Good linearity (R(2) ⩾ 0.99) and no lack of fit was observed (95% confidence interval; F-test, p > 0.05). Also good recovery (89-110%) and satisfactory precision: repeatability (RSD ⩽ 14.9%) and within-laboratory reproducibility (RSD ⩽ 17.2%) were obtained. Analysis of cooked ham and salami sausage samples proved the applicability of both methods for routine analysis.