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HIGHLIGHTS Prolonged frozen storage (up to 24 months) affects certain meat quality parameters, with different behaviours depending on the deep-frozen meat product evaluated. The differences could be justified by the fat content and the surface area. Even differences were described in meat quality during frozen storage, all parameters assessed remained acceptable with minimal quality deterioration Hence, extended storage of up to 24 months could be a suitable strategy for preserving the high quality of Iberian pork

As storage temperature impacts frozen meat quality, we evaluated the ideal freezing and storage temperatures for pork loin, and effects of long-term storage at − 60, − 50, and − 18 °C on pork loin physicochemical properties. Pork loin was cut into 30 × 30 × 30 mm (50 g) and packed in air-containing box. Thereafter, they were stored at different freezing temperature for 6 months. Frozen pork loins were thawed at 4 °C. Samples frozen at − 18 °C exhibited surface dehydration (at 3 months) and high moisture loss surface dehydration-induced discoloration and toughening. However, samples frozen by deep freezing temperature (− 60 and − 50 °C) had lower values of thawing loss, WHC, and shear force than those of frozen at − 18 °C. Samples frozen at − 60 and − 50 °C maintained their freshness better than those frozen at − 18 °C; samples stored at − 60 °C showed significantly lower VBN than those stored at − 50 °C. Therefore, − 60 °C is suitable for freezing pork loins.

The handling and treatment of biological samples is critical when characterizing the composition of the intestinal microbiota between different ecological niches or diseases. Specifically, exposure of fecal samples to room temperature or long term storage in deep freezing conditions may alter the composition of the microbiota. Thus, we stored fecal samples at room temperature and monitored the stability of the microbiota over twenty four hours. We also investigated the stability of the microbiota in fecal samples during a six month storage period at -80°C. As the stability of the fecal microbiota may be affected by intestinal disease, we analyzed two healthy controls and two patients with irritable bowel syndrome (IBS). We used high-throughput pyrosequencing of the 16S rRNA gene to characterize the microbiota in fecal samples stored at room temperature or -80°C at six and seven time points, respectively. The composition of microbial communities in IBS patients and healthy controls were determined and compared using the Quantitative Insights Into Microbial Ecology (QIIME) pipeline. The composition of the microbiota in fecal samples stored for different lengths of time at room temperature or -80°C clustered strongly based on the host each sample originated from. Our data demonstrates that fecal samples exposed to room or deep freezing temperatures for up to twenty four hours and six months, respectively, exhibit a microbial composition and diversity that shares more identity with its host of origin than any other sample.

The amounts of certain heavy metals in waterfowl fluctuate depending on a number of factors. The use of feathers in heavy metal contamination studies is gaining popularity for several reasons, including the lack of need for deep freezing for sample preservation, the fact that it is a non-destructive, non-invasive method that does not require killing an individual, and the ability to predict lead and cadmium concentrations in internal tissues. A total of 22 publications from eight Asian countries including Pakistan, China, Hong Kong, India, Iran, South Korea, Indonesia, and Japan were identified and analysed in this study. The highest number of study sites were found from Pakistan ( n  = 12), followed by China ( n  = 9), Hong Kong, South Korea, and India ( n  = 7) each. A total of 10 heavy metals, viz cadmium, chromium, lead, copper, nickel, zinc, iron, mercury, selenium, and arsenic, have been identified for the review. Mercury (0.17–79.66 ppm) has been studied in all 44 species, whereas selenium (0.98–4.88 ppm) has only been studied in five species. Mercury (8.6 ppm) contamination is highest in Painted Stork from India. Cadmium, lead, copper, and arsenic contamination was detected in the highest concentrations in Cattle Egret and Indian Pond Heron. The highest contamination of cadmium (41.1 ppm), lead (296 ppm), and arsenic (20 ppm) were found in Cattle Egret from Pakistan. Chromium, nickel, and zinc contamination was highest in waders such as Marsh Sandpiper (114.7 ppm), Little Ringed Plover (114.8 ppm), and Little Stint (328.4 ppm), respectively from India. Black-tailed Gull from South Korea had the highest contamination of Iron (4055.55 ppm) and selenium (7.55 ppm). Feather analysis is not an alternative of internal tissue analysis. It should be considered as an initial warning of the hazardous effects of the heavy metals in the waterbirds.

This study investigated the effects of deep freezing and storage temperature (–50°C, –60°C, and –80°C) on the quality and freshness of lamb. To compare the qualities of deep frozen and stored lamb, fresh control and normal freezing conditions (–18°C) were adopted. As quality and freshness parameters, drip loss (thawing loss and cooking loss), water-holding capacity (WHC), texture profile analysis (TPA), thiobarbituric acid reactive substances (TBARS), and total volatile basic nitrogen (TVBN) were evaluated during 5 months of storage. Temperature influenced the drip loss and WHC, and deep freezing minimized the moisture loss during frozen storage compared to the normal freezing condition. Lamb frozen and stored at deep freezing temperature showed better tenderness than that stored in normal freezing conditions. In particular, lamb frozen at lower than –60°C exhibited fresh lamb-like tenderness. Regardless of temperature, evidence of lipid oxidation was not found in any frozen lamb after 5 months, while TVBN was dependent on the applied temperature. Therefore, this study demonstrated that deep freezing could potentially be used to maintain freshness of lamb for 5 months. From the quality and economic aspects, the freezing and storage condition of –60°C is estimated as the optimum condition for frozen lamb.

The utilization of cryopreserved human allografts is a recommended option in the septic vascular surgical field, if autologous graft is not available. These grafts are subjected to deep freezing and stored at − 80 °C until further utilization. The goal of our investigation was to determine the effect of cryopreservation on the structure of vessel wall as a function of storage time, using freshly excised porcine aortic grafts. The samples were subjected to deep freezing and cryopreservation at − 80 °C. Following immediately, 1, 2, 4, 6, 8 and 12 weeks after cryopreservation, differential scanning calorimetry (DSC) and routine histological examination were performed, comparing the structure of frozen grafts to fresh, native aortic wall. Light microscopy evaluation did not show significant changes in the structure of aortic wall at different time points; however, DSC measurements demonstrated a systematic decrease in the thermal stability up to the 6th week and then improvement and stabilization regarding this parameter till the 12th week. Our histological data suggest that cryopreservation causes only minor alteration in the microstructure of fibres in the first three months; thus, the utilization of deep-freeze biological grafts with this short storage time could give favourable outcome.

In order to elucidate whether deep freezing could maintain the quality of snowflake beef, three different deep freezing temperatures (−18 °C, −40 °C, and −60 °C) were used in order to evaluate the changes in tissue structures, quality characteristics and spoilage indexes, and their comparative effects on the quality of snowflake beef. Compared to samples frozen at −18 °C, those stored at −40 °C and −60 °C took a shorter time to exceed the maximum ice crystallization zone (significantly reduced by 2–6 h). In terms of short-term storage, samples frozen at −40 °C and −60 °C had better tissue structure and lower drip loss rate than those frozen at −18 °C; significant differences between groups in drip loss were observed between −18 °C and −60 °C. Moreover, a better bright red color and lower shear force were maintained at −40 °C and −60 °C, with significant differences in shear force between the −18 °C group and the other two groups on day 60. Although there were significant effects on the inhibition of lipid and protein oxidation at −40 °C and −60 °C; no significant variation was observed between these two groups throughout storage. A similar phenomenon was found in flavor, with 1-pentanol identified as an important potential indicator of flavor change in snowflake beef during storage. This study demonstrated that −40 °C and −60 °C had favorable impacts on the quality maintenance of snowflake beef compared to −18 °C. These findings provide a theoretical basis for effective stability of snowflake beef quality during frozen storage.

A study of the 4-day rhythm of the proliferative activity of the embryonic fibroblast-like cells in the logarithmic growth phase was carried out. It was shown that in cell cultures obtained on different days from embryos of different ages, the phase of the 4-day rhythm coincides. In vitro the maxima of the proliferative activity were consistent with the minima of the motor activity of mice. Freezing the culture for 2 or 6 days does not cause a shift in the phase of the 4-day rhythm of cell proliferative activity compare with the unfreezing culture. That indicates the existence of an external synchronizer, which determines the 4-day infradian rhythm of the proliferative activity of embryonic cells. Then we daily thawed samples of single L929 culture of mice fibroblast-like cells for 22 and 17 days and researched the dynamics of its proliferative activity. We also showed 4-day rhythm of the simultaneous increase in the number of cells for all thawed samples. Taking into account that deep freezing of a culture leads to the cessation of all life processes, the fact we obtained indicates an exogenous mechanism of the formation of about a 4-day rhythm of the proliferative activity of cell culture. Variations of the Earth's magnetic field could be one of the external synchronizers of the infradian rhythm. We studied the increase in number of L929 cell in conditions of a magnetic permalloy screen and showed that the magnetic shielding no affect the parameters of the infradian rhythm of L929 cell proliferative activity. So further searches of the external synchronizers are need.

This research was aimed at utilizing available resources and evaluating the effectiveness of value‐added metrics for fish‐based products, such as fish balls made from various types of fish mince and small tuna (Euthynnus affinis). The fish balls were stored using two distinct approaches: deep freezing (−18°C) for 60 days and refrigeration (4°C). The gustatory approach and the AOAC method were used to gauge the nutritional content and aesthetic effectiveness of the fish products, respectively. The deep‐frozen samples exhibited improved crispness compared to those stored in the refrigerator. Deep‐frozen fish balls had substantially lower pH, total volatile base‐nitrogen (TVB‐N), trimethylamine nitrogen (TMA‐N), and histamine concentrations during the storage period ( p < 0.05) than chilled fish balls. Salmonella species were not detected during the diagnostic process, while the Escherichia coli plate count in the deep‐frozen fish balls significantly decreased to just under 10 5 cfu/g. Fish mince‐based value‐added seafood products could help Bangladesh utilize its resources more efficiently and contribute to maintaining sustainable food production. Furthermore, minimal adverse nutritional effects were observed, and the tuna fish balls remained safe for consumption after storage at −18°C for 60 days.

Chia seeds (Salvia hispanica L.) when immersed in water, produce a highly viscous solution due to the release of mucilage, high molecular weight complex carbohydrates with wide application in the food industry. Thus, this study involves development of method for extracting mucilage from chia seed based on mechanical process and low temperature. The method involve extraction by cold pressing and drying by freeze-drying, which was compared to the traditional hot extraction method. The chia seed mucilage cultivated in Brazil was extracted successfully using the previously mentioned extraction method. Rheological analysis including thixotropy, flow curve and frequency sweep of mucilage was done. Microstructure was examined by scanning electron microscopy. The optimal process at 27 °C gave yield of 8.46%. The rheograms showed that the apparent viscosity decreased with increase in shear rate and this effect was most notable in the dispersions obtained by cold extraction and with high concentrations. The gum obtained using CE presented higher values for thixotropic behavior. The storage modulus (G′) was consistently higher than the loss modulus (G″) and the data indicated formation of ‘weak gel’ structure of the dispersions. SEM indicated macroscopic fibrous structure of mucilage obtained through cold extraction process, indicating that the macromolecular network formed by fibrous material contained in mucilage maintained its structure in the process of deep freezing and freeze-drying.