Hydrodynamic shockwave tenderization effects using a cylinder processor on early deboned broiler breasts

A review on underwater shockwave processing and its application in food technology

Underwater shockwave processing (USP) is a non-thermal food processing method where a high-energy impulse is generated near a food product submerged in a liquid. The resulting shockwave transfers energy to the food, and is used to improve quality, safety, and nutritional aspects. This review presents the origin and evolution of the technology, principles of shockwave generation, mechanism of action, and applications in the food industry. The most common food application of USP is currently meat tenderization, where it is used to improve the sensory characteristics of meat as a value-added process. The use of USP as a pretreatment process has also been investigated to increase the yield and nutritional value of extracted juice and oil via softening of plant tissues. This technique also has an impact on food-borne pathogens and spoilage microorganisms in food, however, it is more effective when combined with other hurdles. Major challenges facing the industrial implementation of underwater shockwave technology include the lack of appropriate packaging materials resistant to the disruptive effects of shockwaves, the capital investment required, and a lack of regulatory information pertaining to USP. So far, most studies of underwater shockwaves on food are at the laboratory scale and validation stage. Further research endeavors and collaboration between food scientists, engineers, and regulators are necessary to scale up this technology to industrial implementation.

Shock treatment of corn stover

Corn stover digestibility was enhanced via shock treatment. A slurry of lime-treated corn stover was placed in a partially filled closed vessel. From the ullage space, either a shotgun shell was fired into the slurry, or a gas mixture was detonated. Various conditions were tested (i.e., pressures, depth, solids concentrations, gas mixtures). A high pressurization rate (108,000 MPa/s shotgun shells; 4,160,000 MPa/s hydrogen/oxygen detonation) was the only parameter that improved enzymatic digestibility. Stoichiometric propane/air deflagration had a low pressurization rate (37.2 MPa/s) and did not enhance enzymatic digestibility. Without shock, enzymatic conversion of lime-treated corn stover was 0.80 g glucan digested/g glucan fed with an enzyme loading of 46.7 mg protein/g glucan. With shock, the enzyme loading was reduced by ∼2× while maintaining the same conversion. Detonations are extraordinarily fast; rapidly cycling three small vessels (0.575 m³ each) every 7.5 s enables commercially relevant shock treatment (2,000 tone/day). © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:815-823, 2017.

Effect of electrohydraulic shockwave treatment on tenderness, muscle cathepsin and peptidase activities and microstructure of beef loin steaks from Holstein young bulls

Hydrodynamic pressure processing (HDP) or shockwave treatment improved tenderness (18% reduction in Warner-Bratzler shear force (WBSF) of beef loin steaks. Endogenous muscle proteolyic activities (cathepsins and peptidases) and protein fragmentation of sarcoplasmic and myofibrillar proteins detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) were not influenced by HDP. However, microstructure changes were clearly detected using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Specifically a disruption of the structure at the muscle fiber bundles and an increased endomysium space were observed. The present paper supports the evidence of physical disruption of the muscle fibers as a cause behind the tenderness improvement. The paper discusses the possible mechanisms responsible for the meat tenderisation induced by HDP treatment.

New developments in shockwave technology intended for meat tenderization: Opportunities and challenges. A review

Meat tenderness is an important quality parameter determining consumer acceptance and price. Meat tenderness is difficult to ensure in the global meat chain because the production systems are not always aiming at this purpose (ex.: cattle derived from milk production) and by the existence within the carcass of "tough" primals. Different methods can be used by the meat industry to improve meat tenderness each with its advantages and drawbacks. The application of hydrodynamic pressure or shockwaves has showed outstanding improvements by reducing the Warner Bratzler Shear Force by 25% or more. However, the technology has not penetrated into the market as first systems were based on the use of explosives and further developments seemed to lack the robustness to fulfill industrial requirements. The present paper describes the main challenges to construct a prototype for the continuous treatment of meat by shockwaves based on electrical discharges under water. Finally, improvements on the tenderness of meat by using the novel prototype are presented.

Rapid detection of Salmonella from hydrodynamic pressure-treated poultry using molecular beacon real-time PCR

A real-time polymerase chain reaction (PCR) assay was evaluated to detect Salmonella in hydrodynamic pressure (HDP)-treated chicken using molecular beacon probes available as a commercial kit (iQ-Check, Bio-Rad Laboratories). The sensitivity and accuracy of the assay were compared with the conventional USDA microbiological procedure using artificially contaminated minced chicken. Chicken fillets were irradiated at 10 kGy to completely destroy any naturally occurring Salmonella. These fillets were minced and inoculated with as low as 2+/-1 cfu of S. typhimurium per 25 g chicken. The minced chicken samples were vacuum packed in multi-layer barrier bags, heat shrunk, and treated with HDP. Results showed that all inoculated samples (n=36) were detected by the PCR assay and conventional USDA procedure. Similarly, all uninoculated controls (n=11) were negative by both PCR assay and USDA procedure. As few as 2+/-1 cfu could be detected from 25 g HDP-treated chicken following 16-18 h enrichment in buffered peptone water. Real-time PCR proved to be an effective method for Salmonella detection in HDP-treated chicken with high sensitivity and more importantly, a rapid and high-throughput detection in 18 h, compared to 3-8 days for the conventional microbiological methods. HDP treatment, which has been reported to reduce spoilage bacteria in various meats, was unable to kill pathogenic Salmonella in minced chicken.

Freeze-thaw and cooking effects on broiler breast fillets with extreme initial L* values

Five hundred broiler males were grown to 56 d and processed under common terms. Front halves were deboned 24 h postmortem to obtain breast fillets, and CIELAB light reflectance was measured on the skin side of each fillet 24 h later. All fillets were bagged and frozen (-20 degrees C) for 5 mo. Then the fillets exhibiting the lowest (dark), median (normal), and highest (pale) L* values 48 h postmortem were thawed (3 d at 4 degrees C) and cooked (internal temperature 80 degrees C). Thawing reduced the L* value in the pale fillets and increased it in the dark ones, and cooking further increased L* value and reduced the differences in L*, a*, and b* between groups. Thawing and cooking losses were not affected by initial L* value until they were combined. Total losses increased with initial L*, which was in parallel with a lower increase in thickness after cooking.