Effect of high hydrostatic pressure on the oxidation of washed muscle with added chicken hemoglobin

Impact of high-pressure processing on hemolymph, color, lipid globular structure and oxidation of the edible portion of blood clams

Impact of high-pressure processing (HP-P) on hemolymph and lipid globular structures of the edible portion (EP) of blood clams (BC) was investigated. HP-P above 400 MPa decreased heme iron content, while upsurged non-heme iron content. Increasing pressure induced gaps and abnormal hemocyte cell arrangements. However, HP-P at 300 MPa improved and maintained total hemocyte counts, the heme iron content, and a*-value in BC-EP. For lipid globular structures, the mean diameter drastically decreased when an HP-P pressure of 600 MPa was employed. HP-P at higher pressure induced lipid oxidation, along with decreases in monounsaturated and polyunsaturated fatty acids as well as increases in thiobarbituric acid reactive substances and peroxide value. FTIR spectra displayed a reduction in phosphate groups and cis double bonds in lipids from HP-P treated BC, compared to controls. Therefore, HP-P at 300 MPa is recommended for preparing ready-to-cook BC with less tissue damage and lipid oxidation.

Effects of hemoglobin extracted from Tegillarca granosa on the gut microbiota in iron deficiency anemia mice

Iron deficiency anemia (IDA) is a serious threat to the health of humans around the world. Tegillarca granosa (T. granosa) is considered as an excellent source of iron due to its abundant iron-binding protein hemoglobin. This study aimed to investigate the effects of hemoglobin from T. granosa on the gut microbiota and iron bioavailability in IDA mice. Compared to normal mice, IDA mice showed reduced microbiota diversity and altered relative abundance (reduced Muribaculaceae and increased Bacteroides). After 4 weeks of administration, hemoglobin restored the dysbiosis of the intestinal microbiota induced by IDA and decreased the Firmicutes/Bacteroidota ratio and the abundance of Proteobacteria. Analysis of the hemoglobin regeneration efficiency of mice treated with hemoglobin confirmed that hemoglobin exhibited high iron bioavailability, particularly at low-dose administration, suggesting that a small amount of hemoglobin from T. granosa markedly elevated the blood hemoglobin level in mice. These findings suggested that IDA could be alleviated by administration of hemoglobin with excellent iron bioavailability, and its therapeutic mechanism may be partially attributed to the regulation of the intestinal microbiota composition and relative abundance. These results indicated that T. granosa hemoglobin may be a promising iron supplement to treat IDA and promote the utilization of aquatic-derived proteins.

Impact of dielectric barrier discharge cold plasma on the lipid oxidation, color stability, and protein structures of myoglobin-added washed pork muscle

Cold plasma has been considered a novel non-thermal processing technique and attracted a high attention by the food industry. In this study, the influences of dielectric barrier discharge cold plasma (DBD-CP) on the myoglobin (Mb)-added washed pork muscle (WPM) were evaluated. The electrophoresis pattern, autoxidation, and secondary structure of Mb were analyzed. The results found that DBD-CP caused the decrease of the redness and total sulfhydryl (T-SH) in WPM, while the increase of non-heme, peroxide value (PV), and thiobarbituric acid reactive substances (TBARS), suggested that treatment triggered protein oxidation and heme degradation. Additionally, DBD-CP treatment enhanced the autoxidation of Mb, induced the release of intact heme from the globin, rearranged the charged groups, and promoted Mb aggregation. The transformation of α-helix into the random coil of Mb demonstrated that DBD-CP weakened the tensile strength. Overall, data indicated that DBD-CP promoted autoxidation and changed the secondary structure of Mb, accelerating Mb-mediated lipid oxidation in WPM. Thus, further studies about the optimization of processing conditions by DBD-CP need to be performed.

Absorption of iron from Tegillarca granosa using an in vitro simulated digestion and Caco-2/HepG2 co-culture system

BACKGROUND

Iron-deficiency anemia is one severe micronutrient malnutrition and has captured worldwide attention. This study evaluated the in vitro iron absorption of two iron-binding proteins (hemoglobin and ferritin) from Tegillarca granosa. In addition, the protein structure-iron absorption relationship and the regulatory effect of hepcidin on cellular iron absorption were explored.

RESULTS

Our findings revealed that both hemoglobin and ferritin extracted from T. granosa contained abundant iron-binding sites, as evidenced by stronger peaks in amide I and II regions compared with the two proteins from humans. Less β-sheet (27.67%) structures were found in hemoglobin compared with ferritin (36.40%), probably contributing to its greater digestibility and more release of available iron. This was confirmed by the results of Caco-2/HepG2 cell culture system that showed iron absorption of hemoglobin was 26.10-39.31% higher than that of ferritin with an iron content of 50-150 μmol L^-1 . This high iron absorption of hemoglobin (117.86-174.10 ng mg^-1 ) could also be due to more hepcidin produced by HepG2 cells, thereby preventing ferroportin-mediated iron efflux from Caco-2 cells. In addition, the possible risk of oxidative stress was evaluated in cells post-iron exposure. In comparison with ferrous sulfate, a common iron supplement, Caco-2 cells treated with the iron-binding proteins had a 9.50-25.73% lower level of intracellular reactive oxygen species, indicating the safety of hemoglobin and ferritin.

CONCLUSION

Collectively, the data of this research would be helpful for understanding the key features and potential of developing hemoglobin and ferritin from T. granosa as novel iron supplements. © 2022 Society of Chemical Industry.

Effect of Vacuum Impregnation and High Hydrostatic Pressure Treatments on Shelf Life, Physicochemical, and Sensory Properties of Seabream Fillets

Marination is commonly used to preserve fish, which, in combination with other non-thermal technologies, such as vacuum impregnation and high hydrostatic pressure, may help to preserve freshness and extend shelf life. In addition, marination may mask changes in physicochemical properties and the sensory attributes of fish resulting from intense pressurization treatments. In this study, we evaluated the effects of vacuum impregnation (50 mbar for 5 min) alone or in combination with a moderate pressurization treatment (250 MPa for 6 min) on the physicochemical properties, microbiological and oxidative stability, and sensory properties of refrigerated seabream fillets. Compared to conventional marination, vacuum impregnation alone had no effect on the aforementioned properties, except for a higher perception of lemon aroma (0.9 vs. 1.6). However, vacuum impregnation with pressurization reduced the total viable mesophilic aerobic bacteria to counts below 4 log colony forming units (CFU)/g after 16 days of storage at ≤ 2 °C, compared to 6 log CFU/g with conventional marination. Additionally, the color and texture were affected by the pressurization treatment. However, color was more susceptible, and at the beginning of storage, lightness was higher in the pressurized samples than in the control (52 vs. 78). Regardless, this whitening effect and other minor changes in texture and sensory properties compared to conventional marination with vacuum impregnation with pressurization can be considered of little relevance considering the increase in shelf life, the lack of lipid oxidation (maintained at low and similar levels as those of the non-pressurized samples), and the intrinsic whitening effects of certain marinades.

Effect of hemoglobin extracted from Tegillarca granosa on iron deficiency anemia in mice

Iron deficiency anemia (IDA) is the most common nutritional deficiency in the world. This study was aimed to evaluate the therapeutic effects of hemoglobin from Tegillarca granosa (T. granosa) on IDA in mice. Mice were randomly divided into five groups: a normal control group, an anemia model group, a positive (FeSO₄) control group, a low-dose and high-dose hemoglobin groups. After 4-week iron supplements administration, it was observed that hemoglobin at 2.0 mg iron/kg body weight had better restorative effective on IDA mice than that of FeSO₄ with regard to routine blood parameters and serum biochemical indicators. Meanwhile, the IDA-caused alterations of organ coefficients and liver morphology were ameliorated in mice after hemoglobin supplementation in a dose-dependent manner. Further correlation analysis of indicators showed that serum ferritin (iron storage protein) and soluble transferrin receptor (cellular iron uptake membrane glycoprotein) were susceptible to iron deficiency, indicating possibledisorder of iron metabolism caused by IDA. And levels of serum ferritin and soluble transferrin receptor were restored after administration of hemoglobin. These findings confirmed the safety and effectiveness of T. granosa derived hemoglobin in alleviating IDA in mice, suggesting its great potential as an alternative for iron supplementation.

Bacterial nitric oxide synthase in colorizing meat products: Current development and future directions

Nitrite has been widely used in meat products for its abilities including color formation, antimicrobial properties, flavor formation and preventing lipid oxidation. However, the possible generation of N-nitrosamines through reaction of nitrite with secondary amines arises many concerns in the usage of nitrite. For a long time, nitrite substitution is unsettled issue in the meat industry. Many attempts have been tried, however, the alternative solutions are often ephemeral and palliative. In recent years, bacterial nitric oxide synthase (bNOS) has received attention for its critical roles, especially in reddening meat products. This comprehensive background study summarizes the application of bNOS in colorizing meat products, its functions in bacteria, and methods of regulating the bNOS pathway. Based on this information, some strategies for promoting the nitric oxide yield for effectively substituting nitrite are presented, such as changing the environmental conditions for bacterial survival and adding substrate. Thus, bNOS is a promising nitrite substitute for color formation, and further research on its other roles in meat needs to be carried out to obtain the complete picture.

Preparation, characterization and bioavailability studies of Tegillarca granosa hemoglobin and its glycosylated products

Iron deficiency anemia (IDA) is a common micronutrient deficiency. Tegillarca granosa (T. granosa) is a good source of iron due to its high content of hemoglobin. The present study aimed to determine the effects of glycosylation on structure, physicochemical characteristics and iron bioavailability of hemoglobin. Using Box-Behnken design and response surface methodology, the optimal conditions for hemoglobin-chitosan glycosylation were obtained: 61.8 °C, pH 6.3, hemoglobin/chitosan mass ratio of 4.3 and reaction time of 15 min. The formation of hemoglobin-chitosan conjugates was verified by SDS-PAGE and fluorescence spectroscopy. The surface hydrophobicity of hemoglobin was reduced by 20.90-65.05 % after glycosylation, along with the observations of elevated water-holding capacity, likely owing to the introduction of hydrophilic groups. Antioxidant capacity of glycosylated products (0.41-0.66 μM Trolox/mg protein) was markedly greater than that of original protein (0.06 μM Trolox/mg protein) due to the formation of brown polymers with antioxidant activity. In addition, glycosylation improved in vitro digestibility of hemoglobin by 41.15-69.09 %, which could be attributed to less β-sheet in secondary structures. Moreover, hemoglobin (324.38 ng/mg) exhibited better iron absorption than FeSO₄ (121.63 ng/mg), with the value being further enhanced by glycosylation (442.73 ng/mg), which may be due to the improved protein digestibility and iron-chelating capacity.

Effect of ascorbic acid and citric acid on bioavailability of iron from Tegillarca granosa via an in vitro digestion/Caco-2 cell culture system

Iron deficiency anaemia (IDA) has been receiving worldwide attention. Developing safe and effective iron supplements is of great significance for IDA treatment. Tegillarca granosa (T. granosa), a traditional aquaculture bivalve species in China, is considered to be an excellent source of micronutrients, but the distribution and bioavailability of these minerals have yet to be investigated. The present research was conducted to determine the contents and in vitro enzymatic digestibility of minerals in T. granosa, using beef and wheat flour as reference foods. Meanwhile, two iron-binding proteins, hemoglobin and ferritin, were extracted from T. granosa, and their structures, iron accessibility and bioavailability were investigated. Moreover, the effects of ascorbic acid (AA) and citric acid (CA), two commonly applied dietary factors, on these parameters were evaluated. Our results indicated that the mineral levels varied significantly among different food matrices, with T. granosa showing the highest contents of the tested elements. Comparison of iron absorption of meat versus wheat flour and hemoglobin versus ferritin confirmed that heme iron exhibited higher bioavailability than non-heme iron. The addition of the two organic acids notably enhanced the cellular iron uptake of T. granosa-derived proteins. This could be because AA/CA weakened hydrogen bonds within proteins and caused disordered secondary structures, thereby improving their enzymatic digestibility and releasing more soluble iron to be available for absorption. The results of this study provided a basis for the development of T. granosa-derived protein-based iron supplements, promoting the diverse utilization of marine aquatic resources.

Fennel essential oil loaded porous starch-based microencapsulation as an efficient delivery system for the quality improvement of ground pork

Porous starch (PS) was used as the core material carrier to adsorb fennel essential oil (FEO). Using sodium alginate (SA)-chitosan (CS) as the wall material and glutaraldehyde as the curing cross-linking agent, CS/SA/PS-FEO microcapsules were successfully prepared by polyelectrolyte complex coagulation method. The formation process, structural properties and release behavior of CS/SA/PS-FEO microcapsules were analyzed. The results showed that the essential oil was encapsulated in the form of micro-capsules according to infrared spectroscopy and X-ray diffraction analysis. In open and closed systems, the 16-day cumulative release rate of FEO obtained was 70.62% and 43.87%, respectively indicating that the prepared CS/SA/PS-FEO microcapsules had a good sustained-release ability. The fennel essential oil micro-capsules exhibited good antibacterial and antioxidant activities, delayed the oxidation of fat and protein, reduced the total viable counts, total volatile-base nitrogen and methemoglobin. The textural property and status of water (analyzed by NMR) suggested that the quality of the meat can be maintained for an extended period by incorporating the CS/SA/PS-FEO microcapsules in the minced pork meat.

Determination of the iron bioavailability, conformation, and rheology of iron-binding proteins from Tegillarca granosa

The increased interest in achieving, solely through diet, the same effect on iron levels with supplementation, leads to numerous studies on iron absorption of iron binding proteins (IBPs). The characteristics of IBPs from Tegillarca granosa (T. granosa) and its iron utilization were determined to analyze their relationship. The results showed in T. granosa, Fe(ӀӀ) was main iron form in hemoglobin (TH) and that Fe(ӀӀ) and Fe(ӀӀӀ) coexisted in ferritin (TF). After in vitro digestion, TH was easier to be digested than TF, bovine hemoglobin, and bovine ferritin. In caco-2 cells model, iron bioavailability of TH also was the best, which related to TH's superior fluid properties, higher ratios of α-helix to β-sheet and amide I to amide II. These suggest TH could be used as a good source of organic iron and provide references for application of T. granosa in human nutrition. PRACTICAL APPLICATIONS: This research investigated the iron bioavailability and structural properties of iron-binding proteins from Tegillarca granosa (T. granosa). Moreover, the effects of iron absorption in bovine hemoglobin and ferritin were compared with those from T. granosa. The results showed the hemoglobin in T. granosa had better iron bioavailability and it could be a good source of iron. These data could provide a basic instruction of the application of T. granosa in functional food production.