NaCl Ice Research Articles

Effect of slightly acid electrolysed water ice on metabolite and volatilome profile of shrimp (Penaeus vannamei) during cold storage

Slightly acid electrolyzed water (SAEW) ice has been proven to be effective in preserving shrimp quality during storage in our previous study. The present study aimed to investigate the underlying mechanism of the preservative effect of SAEW ice on metabolic profiles and volatiles production in shrimp during cold storage. The results demonstrated that the SAEW ice retarded the growth of Aeromonas, H2S-producing bacteria, lactic acid bacteria, and Pseudomonas (−2.9, 2.0, 1.6, and 0.7 log CFU/g, respectively), exhibiting better antibacterial activity compared with tap water (TW) ice and NaCl ice. Besides, nuclear magnetic resonance (NMR)-based metabolome combined with volatilome analysis revealed that SAEW ice maintained the contents of umani- and sweetness-related amino acids. Meanwhile, the accumulation of undesirable spoilage-related markers was inhibited, including lactic acid, 2, 3-butanediol, HxR, histidine, ethanol, 2-ethyl-1-hexanol, 2-methyl-butanal, and 3-methyl-butanal (2–10 times reduction compared with the other two groups). This study collaboratively reveals the mechanism of controlling seafood quality by regulating spoilage metabolites through the use of SAEW ice.

Preservative effect of slightly acid electrolysed water ice generated by the developed sanitising unit on shrimp (Penaeus vannamei)

Ice is widely used for the preservation of perishable seafood but not much effective in killing bacteria. Herein, in this study, we aimed to investigate the effect of slightly acid electrolysed water (SAEW) ice on the microbial spoilage together with the quality parameters to elucidate the underlying preservative mechanism. The results indicated that SAEW ice exhibited inhibitory activity toward polyphenol oxidase (PPO) and acid phosphatase (ACP) with 55.3% and 61.9% reduction of activity at day 7, respectively, along with less discolouration and the lowest K-value of shrimp. Besides, the growth of aerobic mesophilic and psychrotrophic bacteria was retarded by SAEW ice treatment (2.4 and 0.4 log CFU/g reduction, respectively). 16S rDNA-based Illumina sequencing elucidated that SAEW ice efficiently retarded the growth of Proteobacteria . Specifically, the growth of major spoilage genus presented in tap water (TW) ice treated shrimp ( Shewanella , Vibrio , and Aeromonas ) and NaCl ice treated shrimp ( Psychrobacter) was inhibited in SAEW ice treated shrimp, which further led to the smallest increase of putrescine and cadaverine, together with the lowest values of pH and TVB-N during storage. The sensory results indicated that SAEW treatment maintained the quality of shrimp during storage in terms of colour, appearance, and texture. Overall, the SAEW ice exhibited a promising preservative effect on shrimp. • SAEW ice exhibited inhibitory activity toward ACP and PPO in shrimp. • Microbiota community was altered by SAEW treatment. • SAEW ice inhibited the growth of Shewanella , Vibrio , Aeromonas and Psychrobacter. • The generated SAEW ice showed promising preservative effect of shrimp.

Application of the metastable impact electron spectroscopy (MIES), in combination with UPS and TPD, to the study of processes at ice surfaces

We report studies of the interaction (80–200 K) of atoms and molecules with ice films, deposited on tungsten, by combining photoelectron spectroscopy, UPS with HeI and II, metastable impact electron spectroscopy (MIES), and temperature programmed desorption (TPD). The focus is on the following issues: Interaction of Na Atoms with films of solid NH3 and CH3OH: the delocalization of the 3sNa electrons and their role in the deprotonation of ice molecules (seen for CH3OH, but not for NH3) is studied. DOS (density of states) information from density functional theory (DFT) is compared with the MIES spectra. It is concluded that the 3s electron, delocalized from its Na core and trapped between the core and surrounding molecules, triggers the CH3OH deprotonation; for NH3, Na dimers appear to play an important role in the delocalization process. Interaction of salt (NaCl) and acid (HCOOH) molecules with H2O ice: neither NaCl nor HCOOH penetrate into the ice film during adsorption below 90 K. However, ionic dissociation of NaCl occurs as a consequence of the NaCl–ice interaction. At 105 K the solvation of ionic species becomes significant. The desorption of H2O from the mixed film takes place between 145 and 170 K; those species bound to Na+ and Cl− are removed last. No dissociation of HCOOH is observed as a consequence of the interaction with ice. Partial solvation of formic acid species takes place above about 120 K whereby these species become embedded into the rim of the water film. However, no deeper penetration of formic acid molecules into the water film can be detected before H2O desorption becomes significant. The TPD spectra of HCOOH display structure, around 160 K, close to or coinciding with the sublimation temperature of water, and around 180 K, caused by species chemisorbed on the tungsten substrate supporting the ice film. The interaction of both NaCl and HCOOH with ice is discussed on the basis of qualitative free energy profiles.

Fatigue Behavior of Cantilever Beams of Saline Ice

A series of in-situ flexural strength and cyclic stress tests were carried out on laboratory-prepared NaCl ice beams, whose average growth rates exceeded those of sea ice. The flexural strengths were all found to be within the accepted range for sea ice, with those beams grown at the slowest rate being strongest, confirming our use of NaCl ice as a sea ice analog. The direction of loading had no observable effect on either the flexural strength or the tangent modulus. An S-N diagram showed no evidence of a fatigue limit nor any significant difference for two different loading frequencies (0.11 and 0.06 Hz). There was no significant dependence of N on porosity of the ice. Loss tangents were typically in the range 0.15–0.25, remaining relatively constant over the duration of the test. The tangent modulus showed considerable variation over the beam population as a whole, and for individual beams decreased steadily over the duration of the test. The loss tangent and tangent modulus showed transient effects for some beams and not others.

Effects of brine content on the strength of frozen Ottawa sand

Abstract Frozen saline Ottawa sand was tested in unconfined compression to establish the effects of the volumetric brine content, vb, on its mechanical behavior. Values of vb were computed from equilibrium phase relations for NaCl ice, and it was found that the failure strength, the failure strain, and the initial tangent modulus all correlate well with this parameter. The applicability of the equation σf = σo(1 - cvkb) in describing the relation between brine content and failure strength, σf, is examined. This equation is often used to describe the failure strength of sea ice. It is found that the equation works well for saline Ottawa sand, but that the values of the constants σo, c, and k depend on the assumptions made in fitting the data.

Effects of Salt Brine Chilling and Hot Boning on Tenderness of Canned Fowl Light Meat

Abstract Two trials were conducted to determine the effects of hot boning and 5% NaCl brine chilling on the tenderness of canned spent hen light meat. Pectoralis superficialis muscles were precooked in water (90 C) to 71 C prior to retort processing [250 C, 1.76 kg/cm2 (25 psi), 30 min] in chicken bouillon. Shear force values for hot boned samples were significantly higher than those for conventionally processed, water-chilled samples. However, the difference in these values was significantly reduced by salt brine chilling the hot-boned fillets for 4 hr in 5% NaCl ice slush. Tenderization of hot-boned fillets was attributed to increased water holding capacity of the meat, which in turn increased tenderness. Salt brine chilling had no significant effect on the shear values of conventionally processed spent hen meat. Analysis showed significantly higher moisture and chloride values for brine-chilled samples, whereas sodium content of the hot-boned, brine-chilled samples was significantly higher than that for other treatments.

Scattering of visible and near infrared radiation by NaCl ice and glacier ice

Abstract Measurements are presented for the phase functions of glacier ice, columnar NaCl ice, and grease ice. Results for glacier ice show a shoulder at 80° characteristic of scattering from vapor bubbles. The NaCl ice types show similar forward scattering but significantly stronger backscattering. The scattering is predominantly due to the brine inclusions, and in the visible region the phase functions are independent of wavelength. For columnar NaCl ice samples, the phase functions depend on sample orientation as well as deflection angle; however, this effect can be ignored for many applications. Orientation-averaged values are presented for general use, and the empirical results are fitted to bimodal Henyey-Greenstein functions.

Laboratory Experiments on Crystal Orientation in NaCl Ice

Over extensive areas of the Arctic and Antarctic, the c-axes of the grains in a sea-ice sheet develop a preferred orientation in a particular direction in the Horizontal plane, causing the physical and electromagnetic properties of the material to be anisotropic. A number of mechanisms have been proposed for this alignment, the more likely including the tilting of floes, horizontal temperature gradient, horizontal deviatone stresses, and oceanic currents. Laboratory experiments have been performed at the Scott Polar Research Institute to distinguish the effects of these mechanisms on the fabric of sea ice. Ho correlation was found between the development of the preferred orientation of c-axes and any of the first three mechanisms. However, in the presence of a current, the strength of the alignment increases rapidly with depth in the ice, the mean c-axis direction coinciding with the current direction. A significant reduction in alignment was produced when the flow was reduced to zero. In addition, upstream deflection of the columnar axis was observed in flowing brine. These results indicate the importance of fluid motion in controlling the rate of transport of solute from the interface and hence the relative growth rates of grains of different orientations.

Laboratory Experiments on Crystal Orientation in NaCl Ice

Over extensive areas of the Arctic and Antarctic, the c-axes of the grains in a sea-ice sheet develop a preferred orientation in a particular direction in the Horizontal plane, causing the physical and electromagnetic properties of the material to be anisotropic. A number of mechanisms have been proposed for this alignment, the more likely including the tilting of floes, horizontal temperature gradient, horizontal deviatone stresses, and oceanic currents. Laboratory experiments have been performed at the Scott Polar Research Institute to distinguish the effects of these mechanisms on the fabric of sea ice. Ho correlation was found between the development of the preferred orientation of c-axes and any of the first three mechanisms. However, in the presence of a current, the strength of the alignment increases rapidly with depth in the ice, the mean c-axis direction coinciding with the current direction. A significant reduction in alignment was produced when the flow was reduced to zero. In addition, upstream deflection of the columnar axis was observed in flowing brine. These results indicate the importance of fluid motion in controlling the rate of transport of solute from the interface and hence the relative growth rates of grains of different orientations.

Thermal Expansion of Saline Ice

AbstractThe coefficient of thermal expansion of NaCl ice and natural sea ice is theoretically shown to be equal to the coefficient of thermal expansion of pure ice.

Thermal Expansion of Saline Ice

AbstractThe coefficient of thermal expansion of NaCl ice and natural sea ice is theoretically shown to be equal to the coefficient of thermal expansion of pure ice.

Effect of Growth Parameters on Substructure Spacing in NaCl Ice Crystals

The effect of growth velocity υ and solute concentration C on the cellular substructure that develops in NaCl ice is studied in the range 3×10−3 to 10−5 cm s−1 and 1 to 100‰ respectively. The substructure is the result of the formation of a constitutionally super-cooled zone in the liquid ahead of the advancing interface. Unidirectional freezing runs were made by placing a cold plate in contact with the “top” of the solution and using cold-plate temperatures of −20 and −70°C. The growth velocities were determined from a least-squares fit of the growth data to a power series. The average spacings between neighboring substructures a0were measured from photomicrographs of precisely located thin sections. Log-log plots of a0against υ show that the slope n gradually changes as a function of υ. In the run where no convection occurred, n changes from to 1 as υ decreases in agreement with the prediction of Bolling and Tiller. The results of Rohatgi and Adams are also shown to be in good agreement with this prediction. On the other hand when convection occurs, n changes from to approximately o as υ decreases. This is caused by convection reducing the effective value at C at the growing interface. The variation of a0with C is quite complex and shows a minimum in the composition range 9 to 25‰ NaCl.

Effect of Growth Parameters on Substructure Spacing in NaCl Ice Crystals

The effect of growth velocity υ and solute concentration C on the cellular substructure that develops in NaCl ice is studied in the range 3×10−3 to 10−5 cm s−1 and 1 to 100‰ respectively. The substructure is the result of the formation of a constitutionally super-cooled zone in the liquid ahead of the advancing interface. Unidirectional freezing runs were made by placing a cold plate in contact with the “top” of the solution and using cold-plate temperatures of −20 and −70°C. The growth velocities were determined from a least-squares fit of the growth data to a power series. The average spacings between neighboring substructures a 0 were measured from photomicrographs of precisely located thin sections. Log-log plots of a 0 against υ show that the slope n gradually changes as a function of υ. In the run where no convection occurred, n changes from to 1 as υ decreases in agreement with the prediction of Bolling and Tiller. The results of Rohatgi and Adams are also shown to be in good agreement with this prediction. On the other hand when convection occurs, n changes from to approximately o as υ decreases. This is caused by convection reducing the effective value at C at the growing interface. The variation of a 0 with C is quite complex and shows a minimum in the composition range 9 to 25‰ NaCl.

Tensile Strength of NaCl Ice

AbstractTo resolve some of the factors causing strength variation in natural sea ice, fresh water and five different NaCl–H2O solutions were frozen in a tank designed to simulate the one-dimensional cooling of natural bodies of water. The resulting ice was structurally similar to lake and sea ice. The salinity of the salt ice varied from 1‰ to 22‰. Tables of brine volumes and densities were computed for these salinities in the temperature range 0° to −35° C. The ring-tensile strength σ of fresh-water ice was found to be essentially temperature independent from −10° to −30°C., with an average value of 29.6±8.5 kg./cm.2at −10° C. The strength of salt ice at temperatures above the eutectic point (–21.2° C.) significantly decreases with brine volumev;. The σ–axis intercept of this line is comparable to the a values determined for fresh ice indicating that there is little, if any, difference in stress concentration between sea and lake ice as a result of the presence of brine pockets. The strength of ice containing NaCl.2H2O is slightly less than the strength of freshwater ice and is independent of the volume of solid salt and the ice temperature. No evidence was found for the existence of either phase or geometric hysteresis in NaCl ice. The strength of ice at sub-eutectic temperatures, however, is decreased appreciably if the ice has been subjected to temperatures above the eutectic point; this is the result of the redistribution of brine during the warm-temperature period. Short-term cooling produces an appreciable (20 per cent) decrease in strength, in fresh-water and NaCl.2H2O ice. The present results are compared with tests on natural sea ice and it is suggested that the strength of freshwater ice is a limit which is approached but not exceeded by cold sea ice and that the reinforcement of brine pockets by Na2SO4.10H2O is either lacking or much less than previously assumed.

Tensile Strength of NaCl Ice

AbstractTo resolve some of the factors causing strength variation in natural sea ice, fresh water and five different NaCl–H2O solutions were frozen in a tank designed to simulate the one-dimensional cooling of natural bodies of water. The resulting ice was structurally similar to lake and sea ice. The salinity of the salt ice varied from 1‰ to 22‰. Tables of brine volumes and densities were computed for these salinities in the temperature range 0° to −35° C. The ring-tensile strength σ of fresh-water ice was found to be essentially temperature independent from −10° to −30°C., with an average value of 29.6±8.5 kg./cm.2at −10° C. The strength of salt ice at temperatures above the eutectic point (–21.2° C.) significantly decreases with brine volumev;. The σ–axis intercept of this line is comparable to the a values determined for fresh ice indicating that there is little, if any, difference in stress concentration between sea and lake ice as a result of the presence of brine pockets. The strength of ice containing NaCl.2H2O is slightly less than the strength of freshwater ice and is independent of the volume of solid salt and the ice temperature. No evidence was found for the existence of either phase or geometric hysteresis in NaCl ice. The strength of ice at sub-eutectic temperatures, however, is decreased appreciably if the ice has been subjected to temperatures above the eutectic point; this is the result of the redistribution of brine during the warm-temperature period. Short-term cooling produces an appreciable (20 per cent) decrease in strength, in fresh-water and NaCl.2H2O ice. The present results are compared with tests on natural sea ice and it is suggested that the strength of freshwater ice is a limit which is approached but not exceeded by cold sea ice and that the reinforcement of brine pockets by Na2SO4.10H2O is either lacking or much less than previously assumed.