The Protection of Quinoa Protein on the Quality of Pork Patties during Freeze-Thaw Cycles: Physicochemical Properties, Sensory Quality and Protein Oxidative

The present study investigated the impact of quinoa protein (QP) on the physicochemical properties, sensory quality, and oxidative stability of myofibrillar protein (MP) in pork patties during five freeze-thaw (F-T) cycles. It was observed that repeated F-T cycles resulted in a deterioration of pork patty quality; however, the incorporation of QP effectively mitigated these changes. Throughout the F-T cycles, the sensory quality of the QP-treated group consistently surpassed that of the control group. After five F-T cycles, the thiobarbituric acid reactive substance (TBARS) content in the control group was measured at 0.423 mg/kg, whereas it significantly decreased to 0.347 mg/kg in the QP-treated group (p < 0.05). Furthermore, QP inclusion led to a decrease in pH and an increase in water-holding capacity (WHC) within pork patties. Following five F-T cycles, Ca2+-ATPase activity exhibited a significant increase of 11.10% in the QP-treated group compared to controls (p < 0.05). Additionally, supplementation with QP resulted in elevated total sulfhydryl content and reduced carbonyl content, Schiff base content, and dityrosine content within myofibrillar proteins (MPs), indicating its inhibitory effect on MP oxidation. In particular, after five F-T cycles, total sulfhydryl content reached 58.66 nmol/mL for the QP-treated group significantly higher than that observed for controls at 43.65 nmol/mL (p < 0.05). While carbonyl content increased from 2.37 nmol/mL to 4.63 nmol/mL between the first and fifth F-T cycle for controls; it only rose from 2.15 nmol/mL to 3.47 nmol/mL in the QP-treated group. The endogenous fluorescence levels were significantly higher (p < 0.05) in the QP-treated group compared to controls. In conclusion, the addition of QP enhanced the quality of pork patties and effectively inhibited the oxidative denaturation of MP during F-T cycles.

Study on the interactions between the screened polyphenols and Penaeus vannamei myosin after freezing treatment

The denaturation of proteins (particularly myosin) due to freezing can lead to the deterioration of Penaeus vannamei. The purpose of this study was to verify the antifreeze protective effects of polyphenols screened by a molecular docking technique, and to explore their interactions with myosin after freezing treatment. It was found that the screened polyphenols could significantly increase the freezing rate and unfreezable water content of shrimp paste. The results of fluorescence spectra indicated that the hesperetin to myosin quenching process included both dynamic and static quenching, and it was primarily bound to myosin through hydrophobic interactions; The quenching of myosin by both dihydroquercetin and mangiferin was static quenching, and they were bound to myosin mainly by hydrogen bonds and van der Waals forces; All three of these polyphenols had only one binding site on myosin. Surface hydrophobicity indicated that all four polyphenols were engaged in non-covalent binding (hydrophobic interactions) with myosin. Infrared spectra demonstrated that the addition of these four polyphenols significantly increased the α-helix content of myosin. They also reduced the myosin particle size, zeta potential, and protein degeneration degree. Scanning electron microscopy revealed that the four polyphenols reduced the degree of aggregation, while more uniformly distributing the myosin particles. These observations provide a basis for the screening of polyphenols and further research into the protective mechanism of polyphenols on frozen myosin.

The investigation of storage situation of fish muscle via the analysis of its exudate by MALDI-TOF MS

The potential of MALDI-TOF MS was investigated in terms of its capability to determine the change of exudates of fish muscle with different freeze-thaw cycles (0, 1 and 2), and frozen storage periods. The exudates were collected from dead chilled marine fish species, large yellow croacker (Larimichthys crocea, LC) and freshly slaughtered freshwater fish species, Japanese seabass (Lateolabrax japonicus) to be studied as models. 109 proteins, in which, 32 are extracellular proteins, and 15 are intracellular proteins, were identified by analyzing exudate of LC using MALDI-TOF MS and HPLC-MS/MS. The results show that the present method may be able to determine the change of fish muscle foods in a more sensitive mode than K value indicated quality control. The feasibility of verifying the storage situation of fish sample was performed by analyzing fish samples obtained from the local market. It is promising to estimate the storage situation of fishery products or other animal muscle foods by analyzing their muscle exudates based on the presently developed strategy.

Biochemical Characterization and Storage Stability of Process Waters from Industrial Shrimp Production

Shrimp boiling water (SBW) and shrimp peeling water (SPW), generated during shrimp processing, were characterized in terms of crude composition, volatile compounds, as well as nutritional and potentially toxic elements over a 13 month sampling period. The storage stability of both waters was also evaluated. Results showed that SBW contained on median 14.8 g/L protein and 2.2 g/L total fatty acids with up to 50% comprising eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Astaxanthin esters, which dominated the total astaxanthin, were 2.8 mg/L on median. SPW, on the other hand, contained on median 1.0 g/L of protein, 0.21 g/L of total fatty acids, and 1.2 mg/L astaxanthin esters. For both side-streams, essential amino acids were up to 50% of total amino acids. For SBW and SPW, the most abundant nutritional elements were Na, K, P, Ca, Cu, and Zn. The contents of all potentially toxic elements were below the detection limits, except for As. SBW was more stable at 4 °C compared to SPW as shown, e.g., by thiobarbituric acid reactive substances and relative changes in total volatile basic nitrogen. The extensive compositional mapping of SBW/SPW provides crucial knowledge necessary in the exploitation and value-adding of such side-streams into food or feed products.

Occurrence and Development of Off-Odor Compounds in Farmed Hybrid Catfish (Clarias macrocephalus × Clarias gariepinus) Muscle during Refrigerated Storage: Chemical and Volatilomic Analysis

The goal of this study was to examine the changes in chemical parameters, major volatile compounds, and sensory aspects in farm-raised hybrid catfish (i.e., dorsal, lateral line and ventral muscles) during a 15-day period of refrigerated storage. Trichloroacetic acid-soluble peptides, free fatty acid, total volatile base-nitrogen (TVB-N), and non-heme iron levels in all muscles increased as storage time proceeded. The levels of trans-1,10-dimethyl-trans-9-decalol (geosmin) and 2-methylisoborneol (2-MIB) were higher than their thresholds, which was connected to a stronger earthy odor. The concentrations of geosmin and 2-MIB in all muscles increased, although there was a consistent trend of earthy odor throughout storage; this phenomenon could be attributed to the masking effect of other off-odors. During storage, the largest lipid oxidation was found in ventral muscle, as measured by peroxide value and thiobarbituric acid reactive substances. During storage, the formation of the most volatile products increased in the lateral line and ventral muscle, whereas the dorsal muscle had the lowest concentration. As storage time proceeded, the strength of spoiled, fishy, rancid, and overall off-odor intensity of all tested muscles tended to rise. Those alterations were linked to higher levels of TVB-N and trimethylamine, as well as all other volatile lipid oxidation products (e.g., hexanal, propanal, 2,4 heptadienal, 1-octen-3-ol, octanal, nonanal, trans-2-heptenal, and 1-hexanol).

Effect of Zataria multiflora essential oil and potassium sorbate on inoculated Listeria monocytogenes, microbial and chemical quality of raw trout fillet during refrigerator storage

Human listeriosis is predominantly associated with contaminated food consumption, including seafood, shrimp, and RTE foods. Listeria monocytogenes is a foodborne pathogen that is mainly found in freshwater, seawater, and fish mucus. Seafood contamination can occur during food processing. L.monocytogenes levels of below 100 cfu/g can be found in seafood samples. The present study was conducted to investigates the effect of Zataria multiflora essential oil (ZEO) and potassium sorbate (PS) on microbial and chemical changes in raw rainbow trout at 4°C to extent shelf life and improve food safety. First, the chemical compositions of ZEO were identified. Then, different percentage of ZEO (1.5, 0.8, and 0.5%) and PS (2%) were inoculated in raw fish fillets and analyzed for TVC, TBA, TVB-N, pH, sensory attributes, Pseudomonas aeruginosa, and inoculated L. monocytogenes (1 × 105 cfu/g) survival at 4°C for 12 days. The best sensory evaluation score was observed for the samples treated with 0.8% and 1.5% ZEO. Overall, this study results indicated that the treatment of rainbow trout fillet with 1.5% ZEO is the best method for controlling the growth of L. monocytogenes at refrigerator temperature without any undesirable sensory effects.

Effect of Different Packaging Methods on Protein Oxidation and Degradation of Grouper (Epinephelus coioides) During Refrigerated Storage

This study investigates the effect of different packaging methods-namely, air packaging (AP), vacuum packaging (VP), and modified atmosphere packaging (MAP)-on the protein oxidation and degradation of grouper (Epinephelus coioides) fillets during refrigerated storage. The carbonyl group, myofibril fragmentation index, free amino acids, FTIR of myofibrillar proteins, and total protein SDS-PAGE were determined. The results showed that the protein oxidation degree of the fillets gradually increased as the storage time increased. The FTIR results indicated that the secondary structure transformed from an α-helix to an irregular curl. SDS-PAGE confirmed the degradation of the myosin heavy chain, and that myosin gradually occurred during refrigerated storage. Meanwhile, protein oxidation and degradation were highly correlated. Protein degradation was accelerated by protein oxidation in myofibrils, which included the increase of protein surface hydrophobicity and changes of the secondary structure. In fact, the protein oxidation and degradation of the grouper fillets were effectively inhibited by MAP and VP during refrigerated storage, and MAP (30% N2 and 70% CO2) had the best results.

The influence of lipid content and pretreatment methods on protein conformation in fish (capelin, Mallotus villosus) during smoking and drying

The influence of lipid content and pretreatment methods (blanching and brining) on proteins conformation in fish (Capelin, Mallotus villosus) during drying and smoking were assessed. Soluble protein fractions were examined through changes in salt-soluble proteins, sulfhydryl groups, and disulfide bonds contents. The salt level and moisture content were also evaluated. Conformational changes in muscle protein were significant (p < 0.05) after blanching and during initial drying when moisture content and dryness rates were high. Salt-soluble proteins and total sulfhydryl groups contents reduced, whereas available sulfhydryl group and disulfide bonds contents intensified. The conformational changes were explained by muscle protein denaturation and aggregation ascribed to high temperature and dehydration during processing. The study reports fish protein denaturation to have reduced protein solubility as well as the nutritional value (loss of thermolabile compounds) and yield after smoking. More so, protein aggregation that was significantly (p < 0.05) higher in dried blanched fish could have reduced the dried fish sensory quality. Blanching pretreatment is thus not suitable for commercial capelin drying. Lipids were found to have protective effect against fish protein conformation.

Physicochemical and sensory characterization of three different portions from commercial pirarucu (Arapaima gigas) fillets

Abstract The objective of the present study was to investigate the relevant physicochemical and sensory parameters of three different Arapaima gigas muscle portions. Cranial, medial and caudal portions were analysed regarding their proximate compositions, instrumental colour and texture parameters, and sensory evaluations. The medial and caudal portions exhibited the greatest (P < 0.05) lipid contents and energy values and the lowest (P < 0.05) moisture and carbohydrate levels. The protein contents were similar (P > 0.05) for the different muscle portions. Before cooking, the medial and caudal portions displayed the greatest (P < 0.05) values for lightness, redness, hardness and chewiness. After cooking, no differences ( P > 0.05) were observed between the different muscle portions for the instrumental colour parameters, while the medial portion exhibited lower (P < 0.05) values for hardness and chewiness as compared to the caudal portion. The cranial portion received the lowest (P < 0.05) scores for flavour and overall liking. Thus the Arapaima gigas medial and caudal muscle portions presented the greatest potentials to satisfy the consumer requirements.

The effects of superchilling with modified atmosphere packaging on the physicochemical properties and shelf life of swimming crab

The objective of the present study was to investigate the effects of superchilling with modified atmosphere packaging on the physicochemical properties and shelf life of swimming crab. As the storage time increased, the rates at which the total aerobic plate count, total volatile basic nitrogen, pH, peroxide value and thiobarbituric acid-reactive substances value increase were significantly lower for the superchilling with modified atmosphere packaging (SCS + MAP) treatment compared to superchilling storage (SCS) and chilling storage (CS). With increasing storage time, the carbonyl content of the proteins increased from 1.21 nmol/mg of protein (0 day) to 2.03, 1.87, 1.66 nmol carbonyl/mg protein on the 6th day for CS, SCS and SCS + MAP, respectively. The disulfide bonds increased in a similar manner, and the total sulfhydryl content, salt extractable protein and Ca-ATPase stability decreased. Sodium dodecyl sulphate polyacrylamide gel elcetrophoresis (SDS-PAGE) and microstructure analysis also indicated that SCS + MAP could reduce the degree of protein degradation. These results suggested that superchilling with modified atmosphere packaging offers an effective approach to slowdown protein and lipid oxidation, and extends the shelf life of swimming crab. However, superchilling with high-CO2 packaging had a negative effect on the surface hydrophobicity and drip loss of swimming crab.

Changes in Meat Quality Characteristics of the Sous-vide Cooked Chicken Breast during Refrigerated Storage

This study was performed to investigate the changes in meat quality characteristics of the sous vide cooked chicken breast during refrigerated storage at 4℃ for 14 d between before and after sous-vide cooking. Cooking loss and shear force were significantly increased, whereas expressible drip was significantly decreased along with reduction in the water holding capacity in both of two groups. Redness of meat juice was significantly (p<0.05) increased during storage, and considerably increased in the refrigerated samples after sous-vide cooked at the 7 to 10 d. The thiobarbituric acid reactive substances (TBARS) was significantly increased and was higher in the refrigerator stored chicken breast samples after sous-vide cooking. The volatile basic nitrogen (VBN) value was significantly increased in both groups, but the VBN value of the stored raw meat sample before sous-vide cooking was increased at an early storage, while the VBN value of the stored sample after sous-vide cooking was increased gradually in this study. Total viable counts and coliform counts were significantly decreased during storage, and coliforms were not detected after 7 d of storage in both groups. Salmonella spp. was not detected during the whole studied period. The outcome of this research can provide preliminary data that could be used to apply for further study of chicken breast using sous-vide cooking method that could be attractive to consumers.

Peptide mapping of polymorphic myosin heavy chain isoforms in different muscle types of some freshwater teleosts

A modified SDS-PAGE system has been employed to resolve polymorphic myosin heavy chain (MyHC) isoforms in different muscle types of three freshwater teleosts displaying different modes of respiration, adaptive features and life styles. Investigated species include accessory air-breather Channa punctata along with exclusive aquatic breather major carps Labeo rohita and Catla catla. All the selected species show specificity and expressivity of at least three MyHC isoforms, one each in red, head and pectoral muscles. Chymotryptic peptide maps unambiguously support substructural individuality of each MyHC isoforms with the type-specific dispersal of chymotryptic cleavage sites. Specific Ca(2+)- and Mg(2+)-ATPase activities of natural actomyosin (NAM) of lateral line red muscle of C. punctata were low and less sensitive to pH, but sensitive to KCl concentrations between 0.05 and 0.15 M. In comparison, the specific enzymatic activities of NAM of red muscle from the carps (L. rohita and C. catla) were substantially high with prominent peaks at pH 7.5 and near insensitivity to 0.05-0.15 M KCl, while C. punctata had shown a different response at these molarities. Thus, the data favor a correlation between breathing modes and life style and the differences in pH or ionic strength sensitivities of ATPases. Unique profiles of peptide maps and the dispersal patterns of hydrophobic residues (cleavage sites of chymotrypsin) in MyHC of different muscle types further reflect individuality of their evolutionary histories.