Effect of ice water pretreatment on the quality of Pacific White Shrimps (Litopenaeus vannamei)

Response surface methodology to optimize the sterilization process of slightly acidic electrolyzed water for Chinese shrimp (Fenneropenaeus chinensis) and to investigate its effect on shrimp quality

Chinese shrimps are popular among consumers for their delicious taste and high nutritional value, but they are highly susceptible to deterioration due to microbial contamination with degradation of texture, color and flavor. The aim of this study was to evaluate the effects of available chlorine concentration (ACC), processing time and material-liquid ratio on the bacterial inhibition rate of shrimp treated with slightly acidic electrolyzed water (SAEW). The effective parameters were optimized by response surface methodology to the optimal bactericidal conditions: ACC 88 mg/L, processing time 12 min, and material-liquid ratio 1:4. The actual bactericidal inhibition rate of shrimp under these conditions was 37.60 %. On this basis, the quality, color difference and textural changes of shrimp treated with SAEW, sodium hypochlorite and alkaline electrolytic water were compared and investigated during storage at 4 °C. The combined results showed that the SAEW treatment could extend the shelf-life by more than 2 d.

Effects of high hydrostatic pressure on peelability and quality of crayfish(Procambarus clarkii)

BACKGROUND

Peeling of crayfish is a very important process in production. Crayfish peeling by machine can increase production efficiency and enhance safety in the production process. The tight muscle-shell attachment causes difficulty in peeling freshly caught crayfish. However, few studies have explored the changes in crayfish quality under favorable shell-loosening treatments.

RESULTS

In this study, the shell-loosening properties of crayfish and changes in crayfish quality, microstructure and protein fluorescent features were investigated after high hydrostatic pressure (HHP) treatment. New methods were established to measure the peeling performance of crayfish, which are peelability and meat yield rate (MYR). The normalization of peelability and MYR were verified by different weights of crayfish tails and different treatments. The peeling effect of HHP-treated crayfish was evaluated by a new quantitative measurement method, and MYR was calculated. The results showed that all the HHP treatments reduced crayfish peeling work and increased MYR. The HHP treatment provided better crayfish quality in terms of texture and color and enlarged the shell-loosening gap. Among all HHP treatments, 200 MPa treatment exhibited lower peeling work, higher MYR and an expansion of the shell-loosening gap, reaching up to 573.8 μm. At the same time, 200 MPa treatment could maintain crayfish quality.

CONCLUSION

The findings outlined above suggest that high pressure is a promising method for loosening crayfish shells. 200 MPa is an optimal HHP treatment condition for crayfish peeling, exhibiting a promising application in industrial processing. © 2023 Society of Chemical Industry.

Correlation between physicochemical properties and volatile compound profiles in tilapia muscles subjected to four different thermal processing techniques

This work studied the physicochemical properties and odor profiles of tilapia muscles after exposure to four types of thermal processing methods: microwaving, roasting, boiling, or steaming. The effect of thermal processing on textural properties followed a pH-water state-water content-tissue microstructure-mass loss-textural properties route, expressed in the following manner: microwaving > roasting > steaming ≈ boiling. After processing, muscle pH increased from 6.59 ± 0.10 to 6.73 ± 0.04-7.01 ± 0.06, and hardness changed from 1468.49 ± 180.77 g to 452.76 ± 46.94-10723.66 ± 2898.46 g. Gas chromatography-based E-nose analysis confirmed that these methods had significant odor fingerprint effects on the tilapia muscles. Finally, the combined analysis of headspace solid-phase microextraction-gas chromatography-mass spectrometry, statistical MetaboAnalyst, and odor activity value showed that the microwaved, roasted, steamed, and boiled tilapia muscles had, respectively, three (hexanal, nonanal, and decanal), four (2-methyl-butanal, 3-methyl-butanal, decanal, and trimethylamine), one (2-methyl-butanal), and one (decanal) relatively important volatile compounds.

Integrating transcriptomic and metabolomic analysis to understand muscle qualities of red swamp crayfish (Procambarus clarkii) under transport stress

This study investigated the transport stress (crowding stress and duration) on the physicochemical properties, energy metabolism and antioxidant enzyme activities of the red swamp crayfish (Procambarus clarkii) tail muscle (CTM). Besides, transcriptomic and metabolomic were conducted to elucidate the possible mechanism of CTM alternations during transport stress. The survival rate of crayfish gradually decreased with the external crowding stress and crowding time increasing. The transport stress also led to the increased distance among muscle fibers, water mobility and energy consumption, and the decreased of water holding capacity (WHC), hardness of CTM. The hepatopancreas exhibited more sensitive to crowding stress than muscle. The multi-omics analysis revealed that transport stress could interfere the translation and protein folding functions of ribosomal proteins, fatty acid metabolism and degradation, physiological functions of mitochondria in CTM. This study could provide critical information to increase the understanding of the regulation mechanism of crayfish when subjected to transport stress.

Application of high-pressure assisted thermal processing (PATP) at pilot scale for replacing conventional maturation and thermal cooking in whiteleg shrimp (Litopenaeus vannamei)

BACKGROUND

The aim of this work was to examine for the first time the use of high-pressure assisted thermal processing (PATP) (100, 350, 600 MPa; 100 °C; 3 min) at pilot scale for replacing shrimp (Litopenaeus vannamei) maturation and cooking, analyzing its impact on peeling yield, color, texture and sensory properties. Shrimps subjected to conventional maturation (ice; 2 days) and thermal cooking (100 °C; boiling water, 3 min) were used as controls.

RESULTS

PATP treatments at 100-350 MPa improved manual peelability over the control (P ≤ 0.05), maintaining similar peeling yield, color (L*, a*, b*), texture (shear force, shear work) and sensory properties (appearance before and after peeling, flavor, firmness; P < 0.05). However, increasing pressure to 600 MPa clearly overprocessed the samples, making it impossible to remove all the meat from the shell and resulting in a softer texture, 4.1% lower peeling yield and worse sensory quality (P ≤ 0.05).

CONCLUSION

PATP (< 350 MPa; 100 °C) could be an alternative to replace conventional maturation and thermal cooking in the production of cooked shrimps, reducing processing time from days to minutes by performing both processes in a single step. © 2022 Society of Chemical Industry.

Quality and Shelf Life of White Shrimp (Litopenaeus vannamei) Processed with High-Pressure Carbon Dioxide (HPCD) at Subcritical and Supercritical States

Phase changes of carbon dioxide (supercritical or subcritical) depend on its proximity to a pressure of 7.35 MPa and temperature of 31.1°C. Carbon dioxide becomes supercritical and subcritical when it is above and slightly below its critical point, respectively. This study aims to determine the effect of high-pressure CO2 treatments at a pressure of 900 psi, 950 psi (subcritical), and 1100 psi (supercritical) and at holding times of 5, 10, and 15 min on the quality parameters of white shrimp (Litopenaeus vannamei) and to determine the shelf life of white shrimp processed with the best treatment. The results showed that the interaction between pressure and holding time had a significant $\left(p<0.05\right)$ effect on cholesterol, protein, moisture content, and $b\ast$ value, but pressure had a significant effect on carotene content. The best treatment was a supercritical CO2 treatment at 1100 psi for 10 min, which was determined based on a significant reduction in the number of microorganisms and no significant changes in color, texture, and fat content were observed compared with control. The best treatment was applied to process shrimps, which were then stored at 4°C to evaluate the effectiveness of scCO2 treatment on the shelf life. No significant changes were found in PV and lipid in treated and scCO2-treated shrimps during storage, but the treatment significantly affected pH, TVBN, and microbial counts. Among the samples, there was no hedonic difference in all sensory attributes. Supercritical CO2 treatment at 1100 psi for 10 min can be an alternative method for preservation of shrimps.