Effects of freezing treatments on the quality of frozen cooked noodles.

Freezing process is one of the key steps in making frozen cooked noodles. Ice crystal formed in freezing process affects the quality of frozen cooked noodles. In this paper, we studied the effect of freezing treatment on frozen cooked noodles. Frozen cooked noodles were evaluated for microstructure and texture properties explored with a scanning electron microscope and texture analyzer at - 20 °C, - 30 °C and - 40 °C respectively. The results indicated that the microstructure and texture properties of frozen cooked noodles were significantly (P < 0.05) improved by a lower freezing temperature than a higher temperature. This present study also showed that the freezing rate is not the only parameter responsible for microstructure and texture properties that occur during freezing; the difference of flours also can be a factor. These findings, if generally applicable to frozen cooked noodle products, could have important economic implications for the convenience of the food industry.

Effects of ZnO nanoparticle-coated packaging film on pork meat quality during cold storage.

BACKGROUND: There has been limited research on the use of ZnO nanoparticle-coated film for the quality preservation of pork meat under low temperature. In the present study, ZnO nanoparticles were mixed with sodium carboxymethyl cellulose (CMC-Na) to form a nanocomposite film, to investigate the effect of ZnO nanoparticle-coated film on pork meat quality and the growth of bacteria during storage under low temperature. RESULTS: When ZnO nanoparticle-coated film was used as the packaging material for pork meat for 14 days of cold storage at 4 °C, the results demonstrated a significant effect on restricting the increases in total volatile basic nitrogen and pH levels, limiting the decreases of lightness (increased L* value) and redness (increased a* value), and maintaining the water-holding capacity compared to the control pork samples (P < 0.05). The present study also discovered that the ZnO nanoparticle-coated film restrained the increase in total plate count (TPC). When Staphylococcus aureus was used as the representative strain, scanning electron microscopy revealed that ZnO nanoparticles increased the occurrence of cell membrane rupture under cold conditions. CONCLUSION: ZnO nanoparticle-coated film helps retain the quality of pork meat during cold storage by increasing the occurrence of microorganism injury. © 2016 Society of Chemical Industry.

Effect of hydrocolloids on the energy consumption and quality of frozen noodles.

Effects of hydrocolloids such as Sodium polyacrylate, xanthan gum and sodium alginate on the energy consumption and quality of frozen cooked noodles were investigated. Results showed that gelatinization temperature (GT) shortened significantly and texture properties (hardness, firmness, break strength) of frozen cooked noodle were significantly improved by adding different hydrocolloid additives (P < 0.05). Nevertheless, there were no significant differences of glass-transition temperature between hydrocolloid fortified and non fortified frozen cooked noodles. Moreover, the hydrocolloids improved quality of cooked noodle and increased energy consumption, however, xanthan gum showed the best results. The optimized constituents were: sodium polyacrylate 0.13 %, xanthan gum 0.86 %, sodium alginate 0.18 % with predicted sensory scores of 90.30. The study showed that hydrocolloids could be used as modifying agents in frozen cooked noodle process.

[Repair mechanism of frozen sublethally damaged Staphylococcus aureus].

OBJECTIVE: To study the repair mechanisms of frozen sublethally damaged Staphylococcus aurous cells. METHODS: We resuscitated frozen sublethally damaged S. aureus at 37 degrees C for different time within 3 h. Meanwhile, we compared the morphological changes of the frozen sublethally damaged cells after 1 h of resuscitation using transmission electron microscopy assay (TEM). The expressions of the transcriptional attenuator MsrR (msrR), iron (Fe3+) ABC transporter ATP-binding protein (fhuC), and cytochrome b (cytB) genes were quantitatively analyzed by real-time fluorescence quantitative PCR (Real-time PCR) method. The content of cells outside leakage, active oxygen (ROS), and superoxide dismutase (SOD) activity were also determined by ultraviolet spectrophotometry. RESULTS: More than 99% of the frozen sublethally damaged S. aureus repaired after 3 h. The resuscitated cells expressed an equal resistance to high concentration of NaCl. Real-time PCR results showed that the msrR and fhuC genes expressions were down-regulated, whereas the cytB gene expression was up-regulated significantly. The frozen sublethally damaged S. aureus cellar surface ultrastructure significant changed during resuscitation. The cell surface became compact and sturdy from smooth and transparent. The cell leakage rate of ultraviolet absorption material gradually decreased. Meanwhile, the intracellular ROS level declined along with the decrease of SOD activity. CONCLUSION: Frozen sublethally damaged cells may regain the capability of resistance to high salt stress by repairing cell membrane integrity, reducing the content of ROS through gene regulation, inhibiting the toxicity of active oxygen to the cells. Meanwhile, the regulation of metabolism related genes (cytB) provides the energy for the requirement of cells, therefore, the frozen sublethally damaged cells were repaired finally.

Glycyrrhetinic acid triggers a protective autophagy by inhibiting the JAK2/STAT3 pathway in cerebral ischemia/reperfusion injury.

Cerebral ischemia/reperfusion injury (CIRI) is a common feature of ischemic stroke leading to a poor prognosis. Effective treatments targeting I/R injury are still insufficient. The study aimed to investigate the mechanisms, by which glycyrrhizic acid (18ß-GA) in ameliorates CIRI. Our results showed that 18ß-GA significantly decreased the infarct volume, neurological deficit scores, and pathological changes in the brain tissue of rats after middle cerebral artery occlusion. Western blotting showed that 18ß-GA inhibited the expression levels of phosphorylated JAK2 and phosphorylated STAT3. Meanwhile, 18ß-GA increased LC3-II protein levels in a reperfusion duration-dependent manner, which was accompanied by an increase in the Bcl-2/Bax ratio. Inhibition of 18ß-GA-induced autophagy by 3-methyladenine (3-MA) enhanced apoptotic cell death. In addition, 18ß-GA inhibited the JAK2/STAT3 pathway, which was largely activated in response to oxygen-glucose deprivation/reoxygenation. However, the JAK2/STAT3 activator colivelin TFA abolished the inhibitory effect of 18ß-GA, suppressed autophagy, and significantly decreased the Bcl-2/Bax ratio. Taken together, these findings suggested that 18ß-GA pretreatment ameliorated CIRI partly by triggering a protective autophagy via the JAK2/STAT3 pathway. Therefore might be a potential drug candidate for treating ischemic stroke.

The Effect of Freeze-Thaw Cycles on the Microscopic Properties of Dumpling Wrappers.

Dumplings are a traditional Chinese food welcomed by Chinese people. Research has indicated that process of quick-frozen wheat cultivars and their gliadins are all related to the quality and shelf-life of dumplings. Therefore, the effect of freeze-thaw cycles on the textural properties and microscopic characteristics of two types of quick-frozen dumpling wrappers (Zhaomai and Wenmai 19) and conformation of their gliadins were investigated. Scanning electron microscopy showed that Wenmai 19 dumpling wrappers had apparent damage after the first cycle, but Zhaomai wrappers did not reveal significant changes until the fourth cycle. The particle size distribution in the starch granules of Wenmai 19 wrappers varied in terms of mechanical damage, but Zhaomai delayed or avoided such effects. FT-IR found a loose protein structure of the gliadins. Differential scanning calorimetry showed that gliadins of Wenmai 19 degenerated more than those of Zhaomai. The crosslinking of gliadin and glutenin maintained a high-quality gluten network, thus protecting the gliadin stability from ice crystals. In turn, the gliadin maintained the strength of the gluten network. Therefore, raw flours with high-quality protein networks are more suitable for frozen dumplings. Freeze-thaw cycles dramatically decreased the textural characteristics of dumpling wrappers and the microscopic characteristics of their gliadin proteins. Concerning wheat cultivars with weak gluten, flours with high-quality protein networks are more suitable as raw materials for frozen dumplings.

[Potential suitable area and niche shift of different ploidy kiwifruit]. / 不同倍性猕猴桃的适生区预测及生态位分化.

Niche shift between polyploid and diploid plants is an important requirement for the success of polyploid. Diploid, tetraploid, and hexaploid of kiwifruit distribute in different areas. Whether there is obvious niche differentiation and the major environmental factors which could influence the ecological niche of different ploidy kiwifruits are still unknown. Based on the natural distribution information collected from literature and by field works, the maximum entropy model (MaxEnt) was used to predict the potentially suitable ranges and the major climatic factors affecting distribution of different ploidy kiwifruits. Niche divergence between different ploidy kiwifruits was quantified by niche identity test. The results showed that there were obvious differences in the potential suitable areas of different ploidy kiwifruits. Diploid occurred in lower altitude Hunan foothills. Tetraploid nearly overlapped with diploid but tended to northern Guizhou and eastern Chongqing. Hexaploid were centered in Guizhou Plateau, northwestern Hunan, southwestern Hubei and southern Shanxi. Hexaploid kiwifruits preferred higher altitudes and latitudes. In addition, the hexaploid had wider highly suitable areas. Results of niche identity test showed overlapped niches between diploid and tetraploid, and different niches between diploid/tetraploid and hexaploid kiwifruits. Minimum temperature of the coldest month (Bio6) and precipitation of the driest month (Bio14) were key environmental factors driving the niche shift of ploidy kiwifruits. Polyploid kiwifruits could maintain a higher probability of existence under lower Bio6 and Bio14, which indicated more extreme niche in cold and arid mountains for polyploids.

[Research progress on the methods for measuring xylem embolism vulnerability]. / æ¤ç‰©æœ¨è´¨éƒ¨æ “å¡žæµ‹å®šæŠ€æœ¯çš„ç ”ç©¶è¿›å±•.

Changes in the frequency and severity of drought events associated with climate change could affect plant growth, development, and adaptability. Hydraulic failure caused by xylem embo-lism is the main physiological consequences of drought stress. How to accurately quantify xylem embolism is particularly important for understanding plant responses to drought stress. The vulnerability of xylem to embolism is usually evaluated by constructing vulnerability curves (VCs). Several methods have been developed to construct VCs, but be inconsistent in their results. A deep understanding of the design principles of xylem embolism measurement methods and comparison of the similarities and differences of various methods in actual research are particularly important for the rational interpretation of literature results, and properly using VCs in models for predicting plant responses to water deficits. Here, we compared seven methods for constructing xylem vulnerability curves to embolism: bench dehydration, centrifugation, air injection, acoustic measurements, synchrotron and X-ray microtomography (Micro-CT), optical visualization method, and pneumatron method. We summarized current achievements and controversial viewpoints of the application of these methods in specific research. Finally, we provided prospects for measuring the vulnerability of xylem embolism and the selection of relevant methods for practical application in future studies.

Colonic obstruction caused by accessory spleen torsion: A rare case report and literature review.

RATIONALE: Accessory spleen torsion is a rare cause of the acute abdomen. The complications of accessory spleen torsion, such as intestinal obstruction, are rarer. We herein report a case of colonic obstruction caused by accessory spleen torsion because of the unusual condition. PATIENT CONCERNS: A 15-year-old patient presented with acute intestinal obstruction with signs of peritoneal irritation. Abdominal computed tomography (CT) and ultrasonography examinations revealed a soft tissue mass in the left midabdomen. Systemic inflammatory response syndrome (SIRS) was observed in this case. DIAGNOSES: The diagnosis of peritonitis and colonic obstruction secondary to accessory spleen torsion was made. Pathologic examination showed infracted splenic tissue. INTERVENTIONS: We performed emergency laparotomy and found that accessory spleen torsion pressured against splenic flexure and descending colon, and caused colon obstruction. The patient underwent accessory splenectomy and enteral decompression. OUTCOMES: At 6 months follow-up, the patient recovered well with perfect digestion. LESSONS: Accessory spleen torsion and its complications are extremely rare. This entity should be considered in differential diagnosis of acute abdomen. However, in case of acute abdomen with critical clinical situation, emergency surgical intervention is necessary for timely diagnosis and treatment.

Inactivation and sublethal injury kinetics of Staphylococcus aureus in broth at low temperature storage.

Low temperatures are widely used to ensure food quality and safety. However, sublethally injured Staphylococcus aureus is an important microbiological safety concern in low temperature food. The objective of this study was to develop predictive inactivation kinetic models for the inactivation and sublethal injury of S. aureus in broth at different temperatures (4 to -18°C) and time points. S. aureus was diluted in tryptic soy broth plus 0.6% (wt/vol) yeast extract (TSBYE) to obtain approximately 10(8) CFU/ml and was stored separately at 4, -3, -11, and -18°C. After specific time points within 96 days, survival of S. aureus was determined on TSBYE and TSBYE agar plus 10% NaCl for enumeration of the total viable and noninjured cell numbers, respectively. Linear, Weibull, and modified Gompertz models were applied to determine survival curve regression. The combination of low temperature and time resulted in S. aureus inactivation, although the cells were able to survive in this sublethal state. Storage temperature was the critical parameter in survival of S. aureus. The modified Weibull model successfully described a second model of noninjured S. aureus cell survival at different low temperatures, whereas only the linear model was able to fit the total viable cells. The predictive model may be used to estimate the level of S. aureus contamination in food at low storage temperatures and times, and it provides new insight into the sublethally injured survival state of S. aureus in low temperature food.