The objective of the study was to investigate the role of emulsified fat (lard) and oil (peanut oil) in the rheology and microstructure of porcine myofibrillar protein (MP) gels. Heat-induced composite gels were prepared from 2% MP with 0% to 15% pre-emulsified lipids at 0.6 M NaCl, pH 6.2. Dynamic rheological testing upon temperature sweeping (20 to 80 degrees C at 2 degrees C/min) showed substantial increases in G' (an elastic modulus) of MP sols/gels with the addition of emulsions. Gel hardness was markedly enhanced (P < 0.05) by incorporating >or=10% emulsions, and the composite gel with 15% lard was 33% more rigid (P < 0.05) than that with 15% peanut oil. Incorporation of both emulsions at 10% or higher levels improved the water holding capacity of the gels by 28% to 44% (P < 0.05). Light microscopy revealed a compact gel structure filled with protein-coated fat/oil globules that interacted with the protein matrix via disulfide bonds. The results indicated that both physical and chemical forces contributed to the enhancements in the rheology, moisture retention, and lipid stabilization in the MP-emulsion composite gels.

No abstract

High-salt diet has been considered to cause health problems, but it is still less known how high-salt diet affects gut microbiota, protein digestion, and passage in the digestive tract. In this study, C57BL/6J mice were fed low- or high-salt diets (0.25 vs. 3.15% NaCl) for 8 weeks, and then gut contents and feces were collected. Fecal microbiota was identified by sequencing the V4 region of 16S ribosomal RNA gene. Proteins and digested products of duodenal, jejunal, cecal, and colonic contents were identified by LC-MS-MS. The results indicated that the high-salt diet increased Firmicutes/Bacteroidetes ratio, the abundances of genera Lachnospiraceae and Ruminococcus (P < 0.05), but decreased the abundance of Lactobacillus (P < 0.05). LC-MS-MS revealed a dynamic change of proteins from the diet, host, and gut microbiota alongside the digestive tract. For dietary proteins, high-salt diet seemed not influence its protein digestion and absorption. For host proteins, 20 proteins of lower abundance were identified in the high-salt diet group in duodenal contents, which were involved in digestive enzymes and pancreatic secretion. However, no significant differentially expressed proteins were detected in jejunal, cecal, and colonic contents. For bacterial proteins, proteins secreted by gut microbiota were involved in energy metabolism, sodium transport, and protein folding. Five proteins (cytidylate kinase, trigger factor, 6-phosphogluconate dehydrogenase, transporter, and undecaprenyl-diphosphatase) had a higher abundance in the high-salt diet group than those in the low-salt group, while two proteins (acetylglutamate kinase and PBSX phage manganese-containing catalase) were over-expressed in the low-salt diet group than in the high-salt group. Consequently, high-salt diet may alter the composition of gut microbiota and has a certain impact on protein digestion.

No abstract

The aim of this research was to compare meat quality characteristics of Cherry Valley (CV), Spent Layer (SL) and Crossbred (CB) ducks. Meat quality, proximate and fatty acid composition were measured in breast and thigh muscles from CV, SL and CB, as well as sensory evaluation of duck soup made from three breeds. The results showed SL contained a highest percentage of protein but lowest moisture than those of CV and intermediate CB (P < 0.05). The L* and b* value of SL ducks were lowest among three breeds (P < 0.05). The breast of SL had higher water-holding capacity compared to CV (P < 0.05), although CV was the most tender among the three breeds (P < 0.05). SL had lower contents of saturated fatty acid and higher contents of unsaturated fatty acids with a more acceptable P/S ratio of 0.57 and n-6/n-3 ratio of 1.52 (P < 0.05). Intramuscular fat and polyunsaturated fatty acids were involved in producing intense aroma and flavor of duck meats. Differences of color and tenderness in meats were attributed to values of L* and cooking loss of muscles. In conclusion, it would be suggested that SL was more suitable for producing duck soup among the three breeds.

In this study, we investigated the antihypertensive effects in vitro and in vivo of novel angiotensin-converting enzyme inhibitory (ACEI) peptides purified and identified from bovine bone gelatin hydrolysate (BGH). Thirteen ACEI peptides were identified from BGH, and among which, RGL-(Hyp)-GL and RGM-(Hyp)-GF exhibited high ACE inhibition with IC50 values of 1.44 and 10.23 μM. Molecular docking predicted that RGM-(Hyp)-GF and ACE residues of Glu384, His513, and Lys511 formed hydrogen-bonding interactions at distances of 2.57, 2.99, and 2.42 + 3.0 Å. RGL-(Hyp)-GL formed hydrogen bonds with Lys511 and Tyr523 and generated hydrogen-bonding interactions with His387 and Glu411 in the zinc­(II) complexation motif at distances of 2.74 and 3.03 + 1.93 Å. The maximal decrements in systolic blood pressure in spontaneously hypertensive rats induced by one-time gavage of RGL-(Hyp)-GL and RGM-(Hyp)-GF at 30 mg/kg were 31.3 and 38.6 mmHg. RGL-(Hyp)-GL had higher enzyme degradation resistance than that of RGM-(Hyp)-GF in vitro incubation in rat plasma, and they were sequentially degraded into pentapeptides and tetrapeptides within 2 h. Our results indicate that BGH can serve as a nutritional candidate to control blood pressure.

The colonization of land by fungi had a significant impact on the terrestrial ecosystem and biogeochemical cycles on Earth surface systems. Although fungi may have diverged ~1500–900 million years ago (Ma) or even as early as 2400 Ma, it is uncertain when fungi first colonized the land. Here we report pyritized fungus-like microfossils preserved in the basal Ediacaran Doushantuo Formation (~635 Ma) in South China. These micro-organisms colonized and were preserved in cryptic karstic cavities formed via meteoric water dissolution related to deglacial isostatic rebound after the terminal Cryogenian snowball Earth event. They are interpreted as eukaryotes and probable fungi, thus providing direct fossil evidence for the colonization of land by fungi and offering a key constraint on fungal terrestrialization.

Passive radiative cooling, a promising strategy for energy savings and sustainability, enables cooling of the ambient temperature by synchronously reflecting sunlight and dissipating heat to the ultracold outer space through the atmospheric transparency window. While designed photonic structures have shown intriguing passive radiative cooling performance, the implementation of such photonic radiators remains challenging due to complex nanoscale lithography/synthesis and rigidity. Here, we experimentally demonstrate a simple and versatile approach of fabricating flexible polydimethylsiloxane radiator thin films with built-in three-dimensional microvoid (inverse-opal-like) arrays for highly efficient daytime radiative cooling. The microvoid-embedded polymer radiator film with tailored spectral responses shows an optimized total reflectivity of ∼93.4% in the sunlight region and a strong infrared emissivity of ∼94.6% within the atmospheric window, respectively. Through such remarkable solar reflection and infrared thermal radiation, the structural polymer radiator achieves subambient cooling of ∼9.8 °C during the night and ∼5.8 °C under direct sunlight in a nonvacuum setup. The three-dimensionally embedded microvoid arrays in our engineered photonic polymer films efficiently backscatter the incident solar radiation and simultaneously enhance the absorption/emissivity in mid-infrared wavelengths, leading to continuous subambient all-day cooling. Our findings provide an effective pathway toward a low-cost, high-performance flexible photonic radiative cooler for passive daytime cooling.