Controlled Freezing-point Storage Research Articles

Effects of different electrostatic field intensities assisted controlled freezing point storage on water holding capacity of fresh meat during the early postmortem period

In this study, the effect of different intensity electrostatic fields on the water holding capacity (WHC) of fresh meat during the early postmortem period in controlled freezing point storage (CFPS) were investigated. Significantly lower cooking loss were found in low voltage electrostatic field (LVEF) and high voltage electrostatic field (HVEF) compared to the control group (CK) (p < 0.05). The myofibril fragmentation index and microstructure results suggested that the sample under HVEF treatment remained relatively intact. It has been revealed that the changes in actomyosin properties under electrostatic field treatment groups were due to the combination and dissociation of actomyosin binding into myofilament concentration, which consequently affects the muscle WHC. The study further demonstrated that the electrostatic field, especially HVEF, might increase the WHC of fresh meat by affecting the distribution of water molecules and physiochemical properties of actomyosin during the early postmortem period.

Changes in the Freshness and Bacterial Community of Fresh Pork in Controlled Freezing Point Storage Assisted by Different Electrostatic Field Usage Frequencies

Changes in the Freshness and Bacterial Community of Fresh Pork in Controlled Freezing Point Storage Assisted by Different Electrostatic Field Usage Frequencies

Changes in water holding capacity of chilled fresh pork in controlled freezing-point storage assisted by different modes of electrostatic field action

Electrostatic field-assisted low-temperature preservation is considered a novel technology, which provides an effective means of extending the shelf-life of meat. This study aimed to investigate the effects of different output time modes of a high voltage electrostatic field (HVEF) on the water holding capacity (WHC) of chilled fresh pork during controlled freezing-point storage. Under a direct current HVEF generator, chilled fresh pork samples were treated by the single, interval, or continuous HVEF treatment, with a control check group receiving no HVEF treatment. It was determined that the WHC of the continuous HVEF treatment higher than the control check group. This difference was proven by analyzing the moisture content, storage loss, centrifugal loss, cooking loss, and nuclear magnetic resonance imaging. Furthermore, the mechanism behind HVEF-assisted controlled freezing-point storage reduced the moisture loss was conducted by examining the changes in the hydration characteristics of myofibrillar protein. The study revealed that myofibrillar proteins exhibit high solubility and low surface hydrophobicity under continuous HVEF. Additionally, continuous HVEF has been demonstrated to effectively maintain the higher WHC and lower hardness of myofibrillar protein gel by inhibiting the water molecule migration. The demonstration of these results showcases the effectiveness of electrostatic fields for the future physical preservation of meat.

Assessment on energy and exergy of combined supercritical CO2 Brayton cycles with sizing printed-circuit-heat-exchangers

The supercritical carbon dioxide Brayton cycle is one of the alternative thermal schemes for advanced energy systems. In this study, ammonia absorption Refrigeration-reheat supercritical carbon dioxide Brayton combined cycle is constructed, and the thermodynamic performance of reheat supercritical carbon dioxide Brayton cycle with ammonia absorption refrigeration cycle are analyzed. The characteristics of Brayton cycle and ammonia absorption refrigeration cycle configuring with Printed Circuit Heat Exchanger are analyzed. The result shows that under controlled freezing-point storage condition, optimized combined cycle energy and exergy efficiency is 46% and 64.98%, electricity output and refrigeration capacity is 11.4 MW and 1.78 MW. Under air-conditioning refrigeration condition, optimized combined cycle energy and exergy efficiency is 50.28% and 65.04%, and electricity output and refrigeration capacity is 11.4 MW and 3 MW. Compared with combined cycle performance before optimization, average improvement of cycle energy efficiency, exergy efficiency and exergy destruction is 4.19%, 0.73% and 3.64%, which shows obvious improvement of cycle performance after optimization. Comparative analysis of printed circuit heat exchanger applied at recuperator and subcooler shows that heat transfer performance of single-faced etched printed circuit heat exchanger in straight channel is better than that of double-faced etched printed circuit heat exchanger for same heat transfer and pressure drop.

Systematic evaluation of the physicochemical properties and the volatile flavors of yak meat during chilled and controlled freezing-point storage.

In this study, the physicochemical properties (total volatile basic nitrogen (TVB-N), pH, and peroxide value) and the volatile flavors of yak meat were systematically evaluated during chilled (0°C) and controlled freezing-point (- 2°C) storage. The TVB-N reached 15.21mg/100g after 18days of storage at 0°C, which exceeded the secondary freshness value according to the Chinese national standard. For storage at - 2°C, the TVB-N did not exceed 15mg/100g until 24days. Compared with storage at 0°C, the samples stored at - 2°C had a slower rate of increase in TVB-N, pH, and peroxide values. The changes in volatile compounds in yak meat during storage at - 2°C and 0°C for 24days were investigated using headspace solid-phase microextraction (HS-SPME) followed by gas chromatography-mass spectrometry (GC-MS). The correlations between the changes in the volatile compound contents and meat quality deterioration revealed significant negative correlations (r min = 0.902, p < 0.05) between some aldehyde flavor components (nonanal, heptanal, benzaldehyde, decanal, and myristal) and TVB-N in the samples stored at controlled freezing-point and chilled temperatures. The decreases in nonanal, benzaldehyde, and myristal contents in yak meat followed zero order reaction kinetics. This result indicated, because of the highly selective and sensitive colorimetric detection method, that volatile compounds can effectively predict the decay in quality of yak meat stored at low temperature in advance. Thus, based on physicochemical and volatile flavor analyses, a new method is proposed to investigate the storage and preservation of yak meat.

ITRAQ-based quantitative proteomics reveals the biochemical mechanism of cold stress adaption of razor clam during controlled freezing-point storage

Razor clam is a major cultivated shellfish of great economic importance and high nutritional value. Due to high corruptible potential, razor clam is generally preserved by controlled freezing-point storage (CFPS). Here, we applied isobaric tags for relative and absolute quantification (iTRAQ) labeling to investigate the biochemical mechanism of cold stress adaption in razor clam during CFPS. In total, 369 proteins were quantified, and 27 of them were identified as differentially expressed proteins during CFPS, mostly involved in energy metabolism process, DNA duplication and protein synthesis, and stress response, specifically, MAPK is the predominant pathway. Further qPCR results revealed H2A and S6K 2 alpha to be the critical post-transcriptionally regulated genes. Our results provided proteomics information with respect to the biochemical mechanism of cold stress adaption in razor clam, shed light on the further elongation of razor clams storage period, and help clarify the novel mechanisms of cold tolerance.

Effects of Controlled Freezing-point Storage on Quality of Fresh-cut Broccoli

Broccoli heads (flower buds) senesced rapidly after harvest at ambient temperatures. The study investigated the changes in the weight loss rate, total soluble solids, ascorbic acid, chlorophyll content, malondialdehyde (MDA) content, polyphenoloxidase (PPO) activity, firmness and the rate of ethylene production of the fresh-cut broccoli stored at different temperatures. The freezing point of fresh-cut broccoli was determined and the fresh-cut broccoli was stored under controlled freezing-point condition (-0.5°C at 4 d, which was significantly lower than the other two storage temperatures. Measurements on other parameters such as weight loss rate, ascorbic acid, PPO activity, chlorophyll content, total soluble solids and MDA content also indicated that controlled freezing-point storage at - 0.5°C could maintain a better product quality.

Super-chilling (−0.7 °C) with high-CO2 packaging inhibits biochemical changes of microbial origin in catfish (Clarias gariepinus) muscle during storage

Controlled freezing-point storage (CFPS) is an emerging preservative technique desirable for fish. In the present study, catfish fillets were stored at −0.7°C under different packaging atmospheres: air (AP), vacuum (VP), and 60% CO2/40% N2 (MAP). Chemical, microbiological, and sensory analyses were performed during storage. Results showed the following descending order of chemical changes (degradation of nucleotides, conversion of protein to volatile-based nitrogen and biogenic amines, and production of trimethylamine nitrogen), as well as loss of sensory properties: 4°C AP>−0.7°C AP≈4°C VP>−0.7°C VP≈4°C MAP>−0.7°C MAP. The chemical changes were well-correlated with microbial growth suggesting the microbiological pathways. Hence, CFPS at −0.7°C in combination with high-CO2 MAP can effectively maintain the quality of fresh catfish meat compared to traditional preservation methods.

Optimal Modified Atmosphere for Packaging and its Effects on Quality and Shelf-life of Pacific White Shrimp (&lt;i&gt;Litopenaeus vannamei&lt;/i&gt;) under Controlled Freezing-point Storage at −0.8°C

Optimal Modified Atmosphere for Packaging and its Effects on Quality and Shelf-life of Pacific White Shrimp (&lt;i&gt;Litopenaeus vannamei&lt;/i&gt;) under Controlled Freezing-point Storage at −0.8°C

Sensory, physicochemical, and microbiological changes in vacuum packed channel catfish (Clarias lazera) patties during controlled freezing-point storage

Sensory, physicochemical, and microbiological changes of channel catfish patties stored under controlled freezing-point storage (CFPS) conditions at -1.5°C for 10 weeks were analyzed to determine useful parameters for freshness evaluation and shelf-life determination. The sensory parameters of aerobic mesophilic and psychrophilic bacterial counts, physicochemical parameters of thiobarbituric acid, total volatile basic nitrogen, chewiness, ATP-ase activity, and the lightness parameter L* were correlated with storage time. Vacuum-packaged patties containing a cryoprotectant, natural antioxidants, and an antimicrobial mixture stored at -1.5°C exhibited an extended shelf-life from a conventional 1–2 weeks to 6 weeks. Parameters that were correlated with storage time can be used as indicators of quality degradation of patties. CFPS combined with vacuum packaging offers an effective approach to extension of catfish product shelflife.

Characteristics of Cell Wall Structure of Green Beans During Controlled Freezing Point Storage

Controlled freezing-point storage means that the storage temperature is in a non-freezing temperature zone between the freezing point of water and food. It has been demonstrated that controlled freezing-point storage can prolong the storage-life of fresh food. Green beans (Phaseolus vulgaris L.) have been planted extensively in the northeast region of China and harvested seasonally. Degradation of cell wall polysaccharides has greatly affected the texture properties of the green bean cell walls. During controlled freezing-point storage, activities of cellulase, pectin methyl esterase, and polygalacturonase were inhibited effectively. It resulted in a slow degradation of cellulose and pectin, less expansion of the cell wall, and less dissolution of pectin layers. As a result, the web structure of the cell wall was preserved. At controlled freezing temperature, the hardness of green beans decreased slightly. Homogalacturonan of chelate pectin was degraded into galacturonic acid, and the side chains of the soluble alkali pectin were degraded into arabinose and galactose. At the later stage of controlled freezing-point storage, the web structure of the cell wall polysaccharides was destroyed. However, the pectin degradation in the green beans was inhibited significantly during controlled freezing-point storage.

Effect of Cold-Induced on Quality of Black Carp Fillet Stored at Controlled Freezing-Point

Taken black carp fillet as the experimental material, effects of cold-induced on the quality of black carp fillets were studied. Three kinds of cold-induced modes were conducted in this experiment: 10°C constant temperature induction ( mode I ); 2°C/2h ( mode II ); 1°C/1h ( mode III ), at the same time did a comparison with controlled freezing-point storage ( mode IV ). The effect of cold-induced on pH, liquid loss, K value, activity of cathepsin B, free amino acid and proteolysis were compared. Results showed that: the pH value in fillets declined mildly at the storage, the drip loss value and K-value of fillets increased gradually as storage time increased. The K-value of fillets stored at mode I and II increased sharply, while relatively little change was observed in mode III and IV. Cathepsin B activities increased little bit at the storage. The cathepsin B activities of mode III was highest at 11.302U•g-1, when fillets were stored at controlled freezing-point (44h). Mode II was the second at 10.522 U•g-1. The total free amino acids (FAAs) of all modes increased to some extent. At 44 hours, the increment of total FAAs in mode II and III were 20.19% and 19.49%, which were superior to mode I (12.27%) and IV (12.97%). No significant differences in protein degradation were observed among those cold-induced modes, but it showed proteolysis on the SDS-PAGE.

Effects of Vacuum and Modified Atmosphere Packaging on Microbial Flora and Shelf-life of Pacific White Shrimp (Litopenaeus vannamei) during Controlled Freezing-point Storage at −0.8°C

Effects of Vacuum and Modified Atmosphere Packaging on Microbial Flora and Shelf-life of Pacific White Shrimp (Litopenaeus vannamei) during Controlled Freezing-point Storage at −0.8°C

English

The aim of this paper was to evaluate the effects of two kinds of storage (controlled freezing-point storage at -1°C and common cold storage at 4°C) on the quality of fresh sweet corn. Besides, perforated package and cold acclimation (5 days at 4°C, followed by 20 days at -1°C) were used as assistive technologies in controlled freezing-point storage to reduce chilly injury. Physico-chemical characters (sugar content, moisture content, weight loss and electrolyte leakage), respiration rate, chilly injury index and sensory evaluation were determined. The results showed that controlled freezing-point storage kept lower respiration rate and sugar loss than common cold storage for sweet corn. Perforated package prevented weight loss, reduced the increase of electrolyte leakage and maintained good sensory attributes. Cold acclimation delayed chilly injury and kept better sensory attributes during controlled freezing-point storage, especially in the latter period. Key words: Sweet corn, controlled freezing-point, chilling injury, cold acclimation, postharvest.

Gene Expression of Periodontal Ligament Cells in Controlled Freezing Point Storage (CFPS) and Cryopreservation

Gene Expression of Periodontal Ligament Cells in Controlled Freezing Point Storage (CFPS) and Cryopreservation

Effects of controlled freezing-point storage at 0 °C on quality of green bean as compared with cold and room-temperature storages

Green bean ( Phaseolus vulgaris L.) was stored under controlled freezing-point condition (0 °C) as compared with room-temperature (25 °C) and cold (8 °C) storages for up to 18 days. Results showed that the peak rate of respiration was 109.2 CO 2 mg/kg h after storage at 0 °C for 12 days, which was significantly lower than those with the other two storage temperatures. Weight loss increased significantly with increasing storage temperature. Measurements on other parameters such as soluble solid and surface colour also indicated that controlled freezing-point storage at 0 °C could maintain better product quality.

Experimental Study on Transplantation of Storage Teeth Using Controlled Freezing-point Storage

Experimental Study on Transplantation of Storage Teeth Using Controlled Freezing-point Storage

移植・再植歯の保存方法に関する研究 保存条件の相違による歯根膜細胞の生物学的活性について

There is an intimated relation between the condition of periodontal ligament tissue and the success of tooth transplantation and replantation. In this study, the biological activity of periodontal ligament tissue after tooth extraction and storage was investigated to establish a long-term storage method for periodontal ligament tissue.Rat incisors were used as the study teeth. UW solution, Euro-Collins solution, DMEM, and sterile physiological saline were used as storage solution. The storage condition were refrigeration (4°C), controlled-freezing point storage (CFP storage;-2°C), and frozen (-80°C), and the storage period was 1-28 days. At the end of the storage period, cell cultures and double fluorescent staining were performed.The results of the cell cultures showed better growth of the periodontal ligament cells in the CFP-storage group than in the refrigeration-storage group or the frozen-storage group, and the results for the 4 different types of storage solution showed the best growth in the UW solution storage group, with a maximum storage period of 21 days. Similarly, double fluorescence staining showed the greatest viable cell fluorescence level in the CFP-storage and UW solution group.The above findings suggested that CFP storage in UW solution is useful for long-term storage of periodontal ligament tissue.