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Chinese shrimp waste hydrolysates (CSWHs) with or without xylose were heated with increasing time (0–180 min) at 115 °C, pH 8.0, to explored characteristics of Maillard reaction and the rules for the formation of flavour in hydrolysates. The results suggested that CSWHs could be modified by Maillard reaction and exhibited stronger pleasant flavour than thermal degradation at proper heating time. During Maillard reaction, significant changes in Maillard reaction products (MRPs) were found, such as the accumulation of intermediate/browning/fluorescent products, the presentation of tempting reddish-brown, compared to Thermal degradation products (TDPs). Meanwhile, a series of volatile compounds and amino acids were found in MRPs, and combined with sensory evaluation, the MRPs exhibited strong meaty and seafood aroma as well as umami and mouthfulness taste. Therefore, Chinese shrimp waste could potentially be used to produce flavoring essence with strong enticing flavour and colour. [ABSTRACT FROM AUTHOR]

The combined effects of a novel ε-polylysine/sodium alginate (PLSA) treatment on the sensory and physicochemical characteristics of Japanese sea bass ( Lateolabrax japonicas ) stored at 4 ± 1 °C for 16 days were investigated. Fish pH value, total volatile basic nitrogen, free fatty acids, K -value, thiobarbituric acid reactive substances, colour, texture, microbiological and sensory quality were measured. Sea bass coated with PLSA maintained flesh colour and tissue hardness, and showed the lower microbial counts, including mesophilic, psychrophilic, enterobacteria, lactic acid bacteria and yeasts compared with the control. In addition, PLSA coating also delayed changes in lipid oxidation, protein degradation and nucleotide breakdown. The results also proved that PLSA coating effectively maintained the sensory quality of sea bass during the storage period. The efficiency was better than that of PL or SA treatment alone. Therefore, the PLSA coating can be applied for preservation of the sea bass to extend its shelf life and improve its preservation quality. [ABSTRACT FROM AUTHOR]

In order to establish an effective freezing method for quality control, the present research evaluated the effects of the different freezing treatments on the quality of Japanese sea bass ( Lateolabrax japonicas ) over a period of 20 days storage at 0 ± 1 °C. Fish pH value, total volatile basic nitrogen (TVB-N), K-value, trimethylamine nitrogen (TMA-N), drip loss, hardness, color, biogenic amines, microbiological characteristics were measured. Sea bass fillets were stored at −18 °C (T1), −55 °C for 24 h and then −18 °C (T2), −55 °C (T3) for 3 months prior to refrigerated storage. T2 showed lower TVB-N, pH value, biogenic amines and drip loss than T3 and T1 did. Significant lower value of bacterial loads, b* value and hardness were observed in T1, T2 and T3 than those of control group. No significant differences were observed among T1, T2 and T3 for TMA-N and a* value. The study demonstrated that Japanese sea bass fillets treated with −55 °C for 24 h and then −18 °C up to 3 months maintain better quality during refrigerated storage. [ABSTRACT FROM AUTHOR]

The effects of magnetic nanoparticles combined with microwave thawing (MNPMT) and magnetic nanoparticles combined with far-infrared thawing (MNPFT) on the freshness and amines content of red seabream fillets were investigated. Four thawing methods were used: microwave thawing (MT), far-infrared thawing (FIRT), magnetic nanoparticles combined with microwave thawing (MNPMT) and magnetic nanoparticles combined with far-infrared thawing (MNPFT). The quality of the fresh sample, the sample after thawing and thawed sample after being stored for 6 h were compared by measuring the freshness indexes such as the volatile amino nitrogen content, thiobarbituric acid content, pH value, total number of viable colonies, and the food safety evaluation indexes such as the formaldehyde, dimethylamine, trimethylamine and putrescine contents. The results showed that MNPFT and MNPMT can maintain better freshness than microwave and far-infrared thawing, and the increase in amines content was significantly inhibited. • Two methods of combined thawing have been proposed. • Effect of four thawing methods on the freshness and safety was analyzed. • Magnetic nanoparticles plus microwave or far infrared thawing works better. [ABSTRACT FROM AUTHOR]

This study investigated the effects of different thawing methods on the quality of largemouth bass. The viscoelastic properties of proteins in Ultrasonics combined with microwave thawing (UMT) and Ultrasonics combined with far-infrared thawing (UIT) samples were closer to FS, which was an indication of good gelation and gel quality. Zeta potential, Raman spectra before and after H/D isotope exchange were used to measure the protein aggregation and the secondary structure of protein. Fourier transform Raman spectra and Raman spectra have been used to investigate the chemical changes in fish lipid during lipid oxidation. Results indicated that both UMT and UIT showed protein stability and gelation property. Thus, it was proved that UMT and UIT could be potentially used to improve the fish quality during thawing process. • Two novel thawing methods have been proposed. • The effects of five thawing methods on fish quality was studied. • UMT and UIT could maintain the quality of the largemouth bass fillets better. [ABSTRACT FROM AUTHOR]

The effects of partial substitution of NaCl with KCl, MgCl 2 and CaCl 2 on gelation properties of myofibrillar protein (MP) mediated by microbial transglutaminase during the heating process were studied, including texture, color, water-holding capacity, rheological properties, Raman spectra and microstructure. Ranking of chlorinated salts efficiency showed NaCl > KCl > MgCl 2  > CaCl 2 . The NaCl and KCl groups of MP gels exhibited similar water-holding capacity and gel strength. The gel strength was all decreased in the MP gels containing KCl, CaCl 2 and MgCl 2 compared to the NaCl group, while the KCl group reduced the gel strength to a less extent. The rheological properties of NaCl and KCl groups showed significant higher G′ and G″ values compared to the control group. Thus, the utilization of chlorinated salts substitutes is a promising way to reduce sodium content in fish products. These results could be used for references in developing low-sodium meat and fish products. [ABSTRACT FROM AUTHOR]

The freshness of turbot stored at 4 ° C for 18 days was assessed using Quality Index Method (QIM), biochemical, and proteomic methods, respectively. Results showed that the developed QIM scheme for turbot consisted of eight parameters which gave a total of 20 demerit points. QI showed a linear relationship to storage time (QI = 1.175 × t days – 0.395, R 2 = 0.988), and the remaining storage time could be estimated with an accuracy of ±1 day. pH, K values, TVB-N, and TVC increased significantly with storage time, and the shelf-life of turbot was determined to have been 15 days. Seven protein spots of interest were screened form the post mortem muscle proteome during storage, and were identified as: phosphoglucomutase-1, pyruvate kinase, kinesin-1 heavy chain, Troponin T, desmin-like, and actin, respectively. They were considered as the potential freshness markers of turbot, since the abundance changes of those proteins were significantly correlated with QI, K value, TVB-N, and TVC, and associated with the loss of fish quality and freshness. The work could provide useful information enabling the development of new strategies for freshness evaluation based on protein markers. [ABSTRACT FROM AUTHOR]

This work was aimed to explore the effects of different thawing strategies on the properties of sea bass myofibrillar protein (MP) and organization structure. Results revealed that magnetic nanometer combined with radio frequency thawing (RT-Mag) and magnetic nanometer combined with microwave thawing (MT-Mag) increased the α-helical content and decreased β-sheet content, while RT-Mag had minimal effect on the secondary protein structure. Low-field nuclear magnetic resonance and SEM analysis revealed that RT-Mag and radio frequency thawing (RT) reduced the mobility and loss of immobilized and non-mobile water, had the most compact and ordered network structure. Decreases in the T max and enthalpies were observed in the thawing treatments expect for RT-Mag during the thawing process. The appearance of polymerized protein band of SDS-PAGE indicated that RT-Mag and MT-Mag occurred a mild oxidation. In addition, the changes of particle size indicated that MP pretreated by RT-Mag and MT-Mag had less aggregation and degradation. The UV second derivative showed that the effect of RT-Mag treatment was closer to that of FS, and the improvement effect of protein aggregation and oxidation was better. Therefore, RT-Mag of New thawing method can be used as an alternative method to improve MP performance and meat quality. ● The two new thawing method of RT-Mag and MT-Mag were adopted. ● Protein structure and thermal stability of sea bass thawed by different methods were studied. ● RT-Mag and MT-Mag could improve MP performance and meat quality. [ABSTRACT FROM AUTHOR]

In this study, cinnamon-perilla essential oil (C-PEO) Pickering nanoemulsions were prepared using collagen as an emulsifier, and the effects of Pickering nanoemulsion addition on the structure and properties of anthocyanidin/chitosan nanocomposite-based edible films were investigated. The compatibility of the anthocyanidin/chitosan nanocomposite-based edible films and C-PEO Pickering emulsions were further analyzed by fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy. As results, Pickering nanoemulsions containing 1% (v/v) C-PEO (C-PEO-2) had the smallest droplet size (11.84 nm). The edible film exhibited better physical properties (i.e., mechanical, water vapor permeability and thermal stability) after adding C-PEO-2. Furthermore, the hydrophobicity and the antioxidant activity of the film were enhanced after incorporating with C-PEO. Finally, the application of the films to chilled (4) fish fillet preservation was also conducted, wrapping with the edible film was effective in controlling quality changes in fish fillets with lower TVB-N and TBAR values during 8 days of chilled storage. Keywords: Cinnamon-perilla essential oil; Pickering nanoemulsions; Anthocyanidin; Chitosan nanoparticles; Fillet preservation. [Display omitted] • Novel edible film based on chitosan nanoparticles was prepared and characterized. • There was no add chemical emulsifier into cinnamon-perilla essential oil. • The properties of the film improved with adding Pickering nanoemulsion. • The shelf life of fillets was extended when packing by the edible film. [ABSTRACT FROM AUTHOR]