Composition of volatile compounds in bovine milk heat treated by instant infusion pasteurization and correlation to sensory analysis

Volatile compounds in skim milk and nonstandardised milk subjected to instant infusion pasteurisation at 80°C, 100°C and 120°C were compared with raw milk, high temperature short time pasteurised milk and milk pasteurised at 85°C/30 s. The composition of volatile compounds differed between infusion pasteurisation treated samples and the reference pasteurisations. The sensory properties of skim milk subjected to instant infusion pasteurisation were described by negative attributes, such as cardboard sour and plastic flavours, which are not associated normally with fresh milk. Partial least squares modelling showed good correlation between the volatile compounds and the sensory properties, indicating the predictive and possible causal importance of the volatile compounds for the sensory characteristics

Transitory Microbial Habitat in the Hyperarid Atacama Desert

Traces of life are nearly ubiquitous on Earth. However, a central unresolved question is whether these traces always indicate an active microbial community or whether, in extreme environments, such as hyperarid deserts, they instead reflect just dormant or dead cells. Although microbial biomass and diversity decrease with increasing aridity in the Atacama Desert, we provide multiple lines of evidence for the presence of an at times metabolically active, microbial community in one of the driest places on Earth. We base this observation on four major lines of evidence: a physico-chemical characterization of the soil habitability after an exceptional rain event, identified biomolecules indicative of potentially active cells [e.g., presence of ATP, phospholipid fatty acids (PLFAs), metabolites, and enzymatic activity], measurements of in situ replication rates of genomes of uncultivated bacteria reconstructed from selected samples, and microbial community patterns specific to soil parameters and depths. We infer that the microbial populations have undergone selection and adaptation in response to their specific soil microenvironment and in particular to the degree of aridity. Collectively, our results highlight that even the hyperarid Atacama Desert can provide a habitable environment for microorganisms that allows them to become metabolically active following an episodic increase in moisture and that once it decreases, so does the activity of the microbiota. These results have implications for the prospect of life on other planets such as Mars, which has transitioned from an earlier wetter environment to today's extreme hyperaridity. [Abstract copyright: Copyright © 2018 the Author(s). Published by PNAS.

Space Telescope and Optical Reverberation Mapping Project. VII. Understanding the Ultraviolet Anomaly in NGC 5548 with X-Ray Spectroscopy

During the Space Telescope and Optical Reverberation Mapping Project observations of NGC 5548, the continuum and emission-line variability became decorrelated during the second half of the six-month-long observing campaign. Here we present Swift and Chandra X-ray spectra of NGC 5548 obtained as part of the campaign. The Swift spectra show that excess flux (relative to a power-law continuum) in the soft X-ray band appears before the start of the anomalous emission-line behavior, peaks during the period of the anomaly, and then declines. This is a model-independent result suggesting that the soft excess is related to the anomaly. We divide the Swift data into on- and off-anomaly spectra to characterize the soft excess via spectral fitting. The cause of the spectral differences is likely due to a change in the intrinsic spectrum rather than to variable obscuration or partial covering. The Chandra spectra have lower signal-to-noise ratios, but are consistent with the Swift data. Our preferred model of the soft excess is emission from an optically thick, warm Comptonizing corona, the effective optical depth of which increases during the anomaly. This model simultaneously explains all three observations: the UV emission-line flux decrease, the soft-excess increase, and the emission-line anomaly

Genome-wide meta-analysis uncovers novel loci influencing circulating leptin levels.

Leptin is an adipocyte-secreted hormone, the circulating levels of which correlate closely with overall adiposity. Although rare mutations in the leptin (LEP) gene are well known to cause leptin deficiency and severe obesity, no common loci regulating circulating leptin levels have been uncovered. Therefore, we performed a genome-wide association study (GWAS) of circulating leptin levels from 32,161 individuals and followed up loci reaching P<10(-6) in 19,979 additional individuals. We identify five loci robustly associated (P<5 × 10(-8)) with leptin levels in/near LEP, SLC32A1, GCKR, CCNL1 and FTO. Although the association of the FTO obesity locus with leptin levels is abolished by adjustment for BMI, associations of the four other loci are independent of adiposity. The GCKR locus was found associated with multiple metabolic traits in previous GWAS and the CCNL1 locus with birth weight. Knockdown experiments in mouse adipose tissue explants show convincing evidence for adipogenin, a regulator of adipocyte differentiation, as the novel causal gene in the SLC32A1 locus influencing leptin levels. Our findings provide novel insights into the regulation of leptin production by adipose tissue and open new avenues for examining the influence of variation in leptin levels on adiposity and metabolic health

Space Telescope and Optical Reverberation Mapping Project. III. Optical Continuum Emission and Broad-band Time Delays in NGC 5548

Galaxie

Instant infusion pasteurisation of bovine milk. II. Effects on indigenous milk enzymes activity and whey protein denaturation

Direct heat treatment of two milk types, skimmed and non-standardised, was performed by instant steam infusion and compared with indirect heating. Infusion conditions were temperatures of 72-120°C combined with holding times of 100-700 ms, and indirect heat conditions were 72°C/15s and 85°C/30 s. The activity of indigenous enzymes; alkaline phosphatase, lactoperoxidase, xanthine oxidase and -glutamyl transpeptidase was evaluated. Mainly the infusion temperature was determinant for inactivation. Whey protein denaturation represented by -lactoglobulin increased significantly with infusion temperature. The non-standardised milk had a higher denaturation rate than skimmed milk. The effect of instant infusion on pH and milk fat globule size in relation to whey protein denaturation and association is discussed

Effect of toasting field beans and of grass-clover: Maize silage ratio on milk production, milk composition and sensory quality of milk

The effect of toasting field beans and of grass-clover: maize silage ratio on milk production, milk composition and sensory quality of the milk was investigated in a 2*2 factorial experiment. Toasting of field beans resulted in lower contents in milk of both fat (44.2 versus 46.1 g/kg, P = 0.02) and protein (33.5 versus 34.2 g/kg, P = 0.008), whereas milk production and urea and somatic cell contents were unaffected compared with untreated field beans. Increasing the proportion of maize silage (from 2 to 5 kg DM/cow/day) in the ration decreased the content of urea in milk (P=0.002), whereas milk production and fat and protein contents were unaffected. Milk from cows fed the high proportion of maize silage had a lower (P=0.04) content of the long chain fatty acids (³ C18). Furthermore, milk from cows fed the high proportion of maize silage had a lower (13-26%) content of luteine (P=0.03), 13-cis-β-carotene (P=0.04) and β-carotene (P=0.05). Toasting of field beans compared with untreated field beans did not affect milk content of carotenoids and had only small effects on fatty acids composition. The sensory profiles of the four milk samples were quite similar characterized by a fatty mouthfeel and creamy flavour, though for the attributes sour feed odour and maize odour there was a significant difference between treatments. In conclusion, toasting field beans did not improve milk production, and toasted field beans in combination with a high proportion of maize in the feed resulted in milk with negative sensory characteristics. Increasing the proportion of maize silage at the expense of grass-clover silage did not affect milk production, but decreased the milk content of long-chain fatty acids, as well as the content of carotenes