Protecting meat color: The interplay of betanin red and myoglobin through antioxidation and coloration.

Myoglobin (Mb) responsible for meat color is easily oxidized resulting in meat discoloration. Here, betanin red (BR), as a natural pigment and antioxidant, was chosen for enhancing redness and inhibiting oxidation. Multiple spectroscopies, isothermal titration calorimetry and molecular docking demonstrated that BR changed the microenvironment of heme group and amino acid residues of Mb, inhibited the oxidation of oxymyoglobin. The main interaction force was hydrogen bond and one variable binding site provided a continuous protective barrier to realize antioxidation. The combination of antioxidation with the inherent red color of BR offered dual color protection effect on processed beef with the addition amount of 0.2 % BR. BR treatment enhanced the redness by 25.59 âˆ¼ 53.24 % and the sensory acceptance by 4.89 âˆ¼ 14.24 %, and decreased the lipid oxidation by 0.58 âˆ¼ 15.92 %. This study paves a theoretical basis for the application of BR and its structural analogues in meat color protection and other quality improvement.

Machine learning approach to predict the biofuel production via biomass gasification and natural gas integrating to develop a low-carbon and environmental-friendly design: Thermodynamic-conceptual assessment.

A hybrid energy cycle (HEC) based on biomass gasification can be suggested as an efficient, modern and low-carbon energy power plant. In the current article, a thermodynamic-conceptual design of a HEC based on biomass and solar energies has been developed in order to generate electric power, heat and hydrogen energy. The planned HEC consists of six main units: two electric energy production units, a heat recovery unit (HRU), a hydrogen energy generation cycle based on water electrolysis, a thermal power generation unit (based on LFR field), and a biofuel production unit (based on biomass gasification process). Conceptual analysis is based on the development of energy, exergy and exergoeconomic assessments. Besides that, the reduction rate of pollutant emission through the planned HEC compared to conventional power plants is presented. In the planned HEC, when hydrogen energy is not needed, excess hydrogen is feed into the combustion chamber to improve system performance and reduce the need for natural gas. Accordingly, the rate of polluting gases emitted from the cycle can be mitigated due to the reduction of fossil fuels consumption. Further, based on the machine learning technique (MLT), the level of biofuel produced from the mentioned process is estimated. In this regard, two algorithms (i.e., Support vector machine and Gaussian process regression) have been employed to develop the prediction model. The findings indicated that the considered HEC can produce about 10.2 MW of electricity, 153 kW of thermal power, and 71.8 kmol/h of hydrogen energy. In both training and testing sets, the Support vector machine model exhibits better behavior compared the two Gaussian process regression model. Based on machine learning technique, with increasing gasification pressure, the level of biofuel obtained from the process does not increase significantly.

Effect of multiple freeze-thaw cycles on water migration, protein conformation and quality attributes of beef longissimus dorsi muscle by real-time low field nuclear magnetic resonance and Raman spectroscopy.

Repeated freezing and thawing (F-T) happens during long-term storage and transportation due to the temperature variation, causing quality deterioration of beef products and influencing consumer acceptance. This study was aimed to investigate the relationship between quality attributes, protein structural changes and water real-time migration of beef with different F-T cycles. The results showed that multiply F-T cycles damaged the muscle microstructure and protein structure tended to denature and unfold, led lower population of water reabsorbed, thus triggering the decrease of water capacity, especially a decrease of T21 and A21 of completely thawed beef samples, finally affected the quality, such as tenderness, color and lipid oxidation of beef muscle. Beef should not be abused by F-T cycles >3 times, the quality extremely degraded when subjected to 5 or more F-T cycles, and real-time LF-NMR provided a new aspect to help us control the thawing process of beef.

Application of electromodulated fluorescence to the study of the dynamics of single-strand oligonucleotides at modified gold surfaces.

Single-strand oligonucleotides with fluorescein labels were immobilized on modified gold electrodes and the surface fluorescence intensity was measured as a function of the potential applied to the electrode. The potential consisted of a constant and sinusoidal parts. The fluorescence was detected synchronously with the sinusoidal component of the potential. Large variation in the electromodulated fluorescence (EmF) was observed as a function of the constant component of the applied potential. In the potential range -0.2 to +0.2 V (vs Ag/AgCl) the EmF signal was quasi-reversible. A model for surface fluorescence was applied to the analysis of the EmF in this potential range. The model assumed that the adsorption-desorption process and quenching by the metal were the dominant mechanisms responsible for the observed EmF. For constant potential more negative than -0.5 V, the observed EmF response appeared to have a contribution from ssDNA in solution. This interpretation was suggested by comparison to EmF from solutions containing free fluorescein or labeled ssDNA. Large variation in the EmF response was observed for electrodes modified with amine and carboxyl groups. This suggests that electrostatic interactions play a dominant role.