Effect of Repeated Freezing-Thawing on Protein Fractions, Textural, and Functional Properties of Few Species of Freshwater Fishes (Indian Major Carps)

Non-destructive prediction of TVB-N using color-texture features of UV-induced fluorescence image for freeze-thaw treated frozen-whole-round tilapia

BACKGROUND

The investigation of UV-induced fluorescence imaging coupled with machine learning was conducted to non-destructively detect the total volatile basic nitrogen (TVB-N) of frozen-whole-round tilapia (FWRT) during freezing and thawing. The UV-induced fluorescence images of FWRT at the wavelength of 365 nm were acquired by self-developed fluorescence image acquisition system. In total, 169 color and texture features based on RGB, hue-saturation-intensity and L*a*b* color spaces and gray level co-occurrence matrix were extracted, respectively. Successive projections algorithm (SPA) was employed to select the optimal 16 features to achieve feature dimension reduction modeling. With full and extracted features as input, the models of partial least squares regression (PLSR), least-squares support vector machine (LSSVM) and convolutional neural network (CNN) were established for TVB-N prediction.

RESULTS

Results indicated that the full features-based CNN performed better than SPA based prediction models (SPA-PLSR and SPA-LSSVM). The CNN model was determined to be the optimal with an RP2 value of 0.9779, RMSEP value of 1.1502 × 10-2  g N kg-1 and RPD value of 6.721 for TVB-N content predictiin.

CONCLUSION

The CNN method based on UV fluorescence imaging technology has potential for quality and safety detection of FWRT. © 2023 Society of Chemical Industry.

Carboxy Methyl Cellulose, Xanthan Gum, and Carrageenan Coatings Reduced Fat Uptake, Protein Oxidation, and Improved Functionality in Deep-Fried Fish Strips: An Application of the Multiobjective Optimization (MOO) Approach

In this study, a multiobjective optimization (MOO) approach was utilized for effective decision-making when several variables were changing simultaneously during frying. Carboxy methyl cellulose (CMC), xanthan gum, and carrageenan coatings in different concentrations (0.25-1.50%, w/v) were applied on fish strips to reduce the oil uptake and protein oxidation during frying. The pickup of the strips increased significantly (p < 0.05) with increasing concentration. The CMC was effective in oil uptake reduction and protein oxidation, as revealed by the lower carbonyl and sulfhydryl contents in the fried strip. The hardness and chewiness of the coated fish strips were found to be declined significantly (p < 0.05) with increasing coating concentrations. The moisture, lipid, toughness, hardness, cutting force, oiliness, sulfhydryl content (all min), oil uptake reduction, and carbonyl content (both max) were considered as multiple criteria for the MOO technique, and fried strips coated with 1% CMC, followed by 0.75% xanthan gum and 0.75% carrageenan, emerged as the best optimal coating.

Physicochemical and structural changes of myofibrillar proteins in muscle foods during thawing: Occurrence, consequences, evidence, and implications

Myofibrillar protein (MP) endows muscle foods with texture and important functional properties, such as water-holding capacity (WHC) and emulsifying and gel-forming abilities. However, thawing deteriorates the physicochemical and structural properties of MPs, significantly affecting the WHC, texture, flavor, and nutritional value of muscle foods. Thawing-induced physicochemical and structural changes in MPs need further investigation and consideration in the scientific development of muscle foods. In this study, we reviewed the literature for the thawing effects on the physicochemical and structural characters of MPs to identify potential associations between MPs and the quality of muscle-based foods. Physicochemical and structural changes of MPs in muscle foods occur because of physical changes during thawing and microenvironmental changes, including heat transfer and phase transformation, moisture activation and migration, microbial activation, and alterations in pH and ionic strength. These changes are not only essential inducements for changes in spatial conformation, surface hydrophobicity, solubility, Ca2+ -ATPase activity, intermolecular interaction, gel properties, and emulsifying properties of MPs but also factors causing MP oxidation, characterized by thiols, carbonyl compounds, free amino groups, dityrosine content, cross-linking, and MP aggregates. Additionally, the WHC, texture, flavor, and nutritional value of muscle foods are closely related to MPs. This review encourages additional work to explore the potential of tempering techniques, as well as the synergistic effects of traditional and innovative thawing technologies, in reducing the oxidation and denaturation of MPs and maintaining the quality of muscle foods.