Puzzling anomalous properties of water are drastically enhanced in the supercooled region. However, the nature of these anomalies is not known. We report here molecular dynamics simulations using the RexPoN force field from 298 to 200 K along the 1 atm density curve. At 298 K, there are 2.1 strong hydrogen bonds (SHBs), leading to a dynamic branched one-dimensional (1D) polymer. Water remains 1D down to 240 K, but at and below 230 K, the number of SHBs becomes 3.0, leading to a two-dimensional (2D) network that persists to 200 K. We propose that this 1D-to-2D topological transition accounts for the anomalous properties of supercooled water. Near 230 K, the power spectra show dramatic increases in the angular vibrational frequency modes, while the diffusivity decreases dramatically, both arising from the 1D-to-2D transformation. This transition is not first order because free energy changes uniformly but fluctuations in the entropy near 230 K suggest a possible second-order transition.
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http://dx.doi.org/10.1021/acs.jpclett.9b02443 | DOI Listing |
Food Chem X
January 2025
School of Food Science and Bioengineering, Tianjin Agricultural College, Tianjin 300384, China.
Low-voltage electrostatic field (LP) enhances the freezing quality of food by increasing water supercooling and improving ice crystal morphology. This study explored the effects of LP treatment on the storage quality of square bamboo shoots using physicochemical, gas chromatography-mass spectrometry, and metabolomics methods. Results showed that with prolonged storage, the LP-treated group had lower activities of peroxidase, phenylalanine ammonia-lyase, and lower levels of malondialdehyde, cellulose, and lignin compared to the control group, while superoxide dismutase and catalase activities and shear force values were higher.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong, Kowloon 999077, China.
Heterogeneous ice nucleation is a widespread phenomenon in nature. Despite extensive research on ice nucleation near biological antifreeze proteins, a probe for ice nucleation and growth processes at the atomic level is still lacking. Herein, we present simulation evidence of the heterogeneous ice nucleation process on the ice-binding surface (IBS) of the antifreeze protein (TmAFP).
View Article and Find Full Text PDFJ Food Sci
January 2025
Department of Human Nutrition, Food, and Animal Sciences, University of Hawai'i at Mānoa, Honolulu, Hawai'i, USA.
Freezing extends the shelf life of foods but often leads to structural damage due to ice crystal formation, negatively impacting quality attributes. Oscillating magnetic field (OMF)-assisted supercooling has emerged as a potential technique to overcome these limitations by inhibiting ice nucleation and maintaining foods in a supercooled state. Despite its potential, the effectiveness and underlying mechanisms of OMF-assisted supercooling remain subjects of debate.
View Article and Find Full Text PDFFood Chem
January 2025
Key Laboratory of Tropical Fruits and Vegetables Quality and Safety for State Market Regulation, Institute of Food Testing, Hainan Academy of Inspection and Testing, Haikou 570314, China. Electronic address:
Ozone (O) is an effective agent for post-harvest fruit preservation against diverse microorganisms. In this study, a cost-effective ozone micro-nano bubbles ice (O-MNBI) was prepared, characterized, and subsequently used to precool litchi. The optimal protocols for O-MNBI production were as follows: water (2 °C, pH = 7) was pumped into a micro-nano O bubble generator for 10 min aeration treatment.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
College of Food Science and Technology, Zhejiang University of Technology, Hangzhou 310014, China; Zhejiang Key Laboratory of Green, Low-carbon and Efficient Development of Marine Fishery Resources, Hangzhou 310014, China; National R&D Branch Center for Pelagic Aquatic Products Processing (Hangzhou), Hangzhou 310014, China. Electronic address:
Slurry ice preparation experiences considerable supercooling, which can be mitigated by nano-nucleating agents. A nano-nucleating agent (CH/PE-TP NPs) was prepared by ultrasonication-assistant self-assembly of chitosan (CH) and pectin (PE), encapsulated with tea polyphenols (TP). Ultrasonication for 10 min downsized self-assembled aggregates from 5.
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