Effect of Irradiation on Quality of Vacuum-Packed Spicy Beef Chops

To develop an alternative pasteurization process for the spicy beef jerky (SBJ), it was treated with irradiation doses of 0, 0.5, 1.5, 3, 4, 6, and 8 kGy and the sensory attributes, texture properties, drip loss, and the protein biological efficiency were studied. The results showed that lightness, drip loss, and off-odor of SBJ increased, while the hardness, chewiness, gumminess, color preference, and taste of SBJ decreased with the increase in irradiation dose. This tendency was obvious as the irradiation dose increased to 6 kGy and 8 kGy. The possible reason for these quality changes might be due to the free radicals produced by irradiation. This speculation is supported by the decrease of the content of capsanthin and the increase of the content of TBARS of SBJ with the increase in irradiation dose. The plate counts of treated SBJ indicated that 4 kGy was suitable for pasteurization of SBJ

Nitrite and nitrate in meat processing: Functions and alternatives

Meat and meat products are important foods in the human diet, but there are concerns about their quality and safety. The discovery of carcinogenic and genotoxic N-nitroso compounds (NOCs) in processed meat products has had serious negative impacts on the meat industry. In order to clarify the relationship between the use of nitrite or nitrate and the safety of meat or meat products, we reviewed NOCs in meat and meat products, the origin and safety implications of NOCs, effects of nitrite and nitrate on meat quality, national regulations, recent publications concerning the using of nitrite and nitrate in meat or meat products, and reduction methods. By comparing and analyzing references, (1) we found antioxidant, flavor improvement and shelf-life extension effects were recently proposed functions of nitrite and nitrate on meat quality, (2) the multiple functions of nitrite and nitrate in meat and meat products couldn't be fully replaced by other food additives at present, (3) we observed that the residual nitrite in raw meat and fried meat products was not well monitored, (4) alternative additives seem to be the most successful methods of replacing nitrite in meat processing, currently. The health risks of consuming processed meat products should be further evaluated, and more effective methods or additives for replacing nitrite or nitrate are needed

Nitrite and nitrate in meat processing: Functions and alternatives

Meat and meat products are important foods in the human diet, but there are concerns about their quality and safety. The discovery of carcinogenic and genotoxic N-nitroso compounds (NOCs) in processed meat products has had serious negative impacts on the meat industry. In order to clarify the relationship between the use of nitrite or nitrate and the safety of meat or meat products, we reviewed NOCs in meat and meat products, the origin and safety implications of NOCs, effects of nitrite and nitrate on meat quality, national regulations, recent publications concerning the using of nitrite and nitrate in meat or meat products, and reduction methods. By comparing and analyzing references, (1) we found antioxidant, flavor improvement and shelf-life extension effects were recently proposed functions of nitrite and nitrate on meat quality, (2) the multiple functions of nitrite and nitrate in meat and meat products couldn't be fully replaced by other food additives at present, (3) we observed that the residual nitrite in raw meat and fried meat products was not well monitored, (4) alternative additives seem to be the most successful methods of replacing nitrite in meat processing, currently. The health risks of consuming processed meat products should be further evaluated, and more effective methods or additives for replacing nitrite or nitrate are needed

Effect of Deep Dormancy Temperature Cultivation on Meat Quality of Crucian Carp (Carassius auratus)

To extend the survival of crucian carp (Carassius auratus) during transportation, the effect of deep dormancy temperature (DDT) cultivation on the crucian carp was investigated by measuring the respiratory rate, survival time, and effect of cooling speed on the meat quality. The results of the respiratory rate and survival time indicated that the DDT of the crucian carp was 1.6 °C. The cooling speed had a significant (p < 0.05) influence on the quality of the crucian carp meat, with a faster cooling speed resulting in a lower pH, L* value, a* value, gumminess, springiness, cohesiveness, stickiness, chewiness, CMP, and UMP content for the crucian carp meat, thus resulting in a lower sensory score for the crucian carp meat. A possible reason for the decrease in the quality of the crucian carp meat is that the faster cooling speed led to a strong stress response and higher anaerobic metabolism in the crucian carp. This can be supported by the contents of the blood glucose and lactic acid in the crucian carp treated with higher cooling speed being significantly (p < 0.05) higher than that of the control. Combining all the results of the cooling speed on the eating quality of the crucian carp meat, a cooling speed of 2 °C/h followed by 1 °C/h was suggested for the survival of crucian carp in transit

Effect of Irradiation on Quality of Vacuum-Packed Spicy Beef Chops

To develop an alternative pasteurization process for the spicy beef jerky (SBJ), it was treated with irradiation doses of 0, 0.5, 1.5, 3, 4, 6, and 8 kGy and the sensory attributes, texture properties, drip loss, and the protein biological efficiency were studied. The results showed that lightness, drip loss, and off-odor of SBJ increased, while the hardness, chewiness, gumminess, color preference, and taste of SBJ decreased with the increase in irradiation dose. This tendency was obvious as the irradiation dose increased to 6 kGy and 8 kGy. The possible reason for these quality changes might be due to the free radicals produced by irradiation. This speculation is supported by the decrease of the content of capsanthin and the increase of the content of TBARS of SBJ with the increase in irradiation dose. The plate counts of treated SBJ indicated that 4 kGy was suitable for pasteurization of SBJ

New Method for 5-Nucleotidase Preparation and Evaluation of Its Catalytic Activity.

In this study, we established a new methodology for preparing 5-nucleotidase (5-NT) with the aim of enhancing our understanding of its enzyme activity and laying a basis for regulating the content of umami-enhancing nucleotides in pork. 5-NT was prepared with Sephadex gel filtration and reverse-phase high-performance liquid chromatography, and its enzymatic properties and catalytic activity were evaluated. The results show that the molecular weight of the prepared 5-NT was 57 kDa, the optimal catalytic temperature was 40 °C, and the optimal pH was 8. Zn2+, and sucrose showed inhibitory effects on the activity of 5-NT, while K+, Na+, Ca2+, Mg2+, glucose, fructose, and trehalose promoted the activity of the studied compound. The prepared 5-NT exhibited higher catalytic activity and selectivity against IMP compared with its commercial counterpart, while its catalytic activity against XMP was not significant (p > 0.05). In brief, we established a new methodology for preparing 5-NT, enhancing our understanding of its enzyme activity and providing a solid basis for regulating the content of umami-enhancing nucleotides in pork through the control of endogenous 5-NT activity

In vitrocartilage tissue engineering using cancellous bone matrix gelatin as a biodegradable scaffold

In this study, we constructed tissue-engineered cartilage using allogeneic cancellous bone matrix gelatin (BMG) as a scaffold. Allogeneic BMG was prepared by sequential defatting, demineralization and denaturation. Isolated rabbit chondrocytes were seeded onto allogeneic cancellous BMG, and cell–BMG constructs were harvested after 1, 3 and 6 weeks for evaluation by hematoxylin and eosin staining for overall morphology, toluidine blue for extracellular matrix (ECM) proteoglycans, immunohistochemical staining for collagen type II and a transmission electron microscope for examining cellular microstructure on BMG. The prepared BMG was highly porous with mechanical strength adjustable by duration of demineralization and was easily trimmed for tissue repair. Cancellous BMG showed favorable porosity for cell habitation and metabolism material exchange with larger pore sizes (100–500 µm) than in cortical BMG (5–15 µm), allowing cell penetration. Cancellous BMG also showed good biocompatibility, which supported chondrocyte proliferation and sustained their differentiated phenotype in culture for up to 6 weeks. Rich and evenly distributed cartilage ECM proteoglycans and collagen type II were observed around chondrocytes on the surface and inside the pores throughout the cancellous BMG. Considering the large supply of banked bone allografts and relatively convenient preparation, our study suggests that allogeneic cancellous BMG is a promising scaffold for cartilage tissue engineering

New Method for 5′−Nucleotidase Preparation and Evaluation of Its Catalytic Activity

In this study, we established a new methodology for preparing 5′−nucleotidase (5′−NT) with the aim of enhancing our understanding of its enzyme activity and laying a basis for regulating the content of umami−enhancing nucleotides in pork. 5′−NT was prepared with Sephadex gel filtration and reverse−phase high−performance liquid chromatography, and its enzymatic properties and catalytic activity were evaluated. The results show that the molecular weight of the prepared 5′−NT was 57 kDa, the optimal catalytic temperature was 40 °C, and the optimal pH was 8. Zn2+, and sucrose showed inhibitory effects on the activity of 5′−NT, while K+, Na+, Ca2+, Mg2+, glucose, fructose, and trehalose promoted the activity of the studied compound. The prepared 5′−NT exhibited higher catalytic activity and selectivity against IMP compared with its commercial counterpart, while its catalytic activity against XMP was not significant (p > 0.05). In brief, we established a new methodology for preparing 5′−NT, enhancing our understanding of its enzyme activity and providing a solid basis for regulating the content of umami−enhancing nucleotides in pork through the control of endogenous 5′−NT activity