Effect Of High Pressure Microfluidization Research Articles

Effect of High-Pressure Micro-Fluidization on the Inactivation of Staphylococcus aureus in Liquid Food.

High-pressure homogenization has been extensively studied for its excellent homogenization effect and the prospect of continuous liquid food production, but its sterilization ability still needs to be improved. In this study, we replaced the homogenization valve with two opposing diamond nozzles (0.05 mm inner diameter) so that the fluid collided at high velocity, corresponding to high-pressure micro-fluidization (HPM). Moreover, HPM treatment significantly inactivated Staphylococcus aureus ~7 log in the liquid with no detectable sub-lethal state at a pressure of 400 MPa and a discharge temperature of 50 °C. The sterilization effect of HPM on S. aureus subsp. aureus was attributed to a significantly disrupted cell structure and increased membrane permeability, which led to the leakage of intracellular proteins, resulting in bacterial death. At the same time, HPM treatment was able to significantly reduce the ability of S. aureus subsp. aureus to form biofilms, which, in turn, reduced its virulence. Finally, compared to the simulated system, more effective sterilization was observed in apple juice, with its color and pH remaining unchanged, which suggested that HPM can be used to process other liquid foods.

Effect of high pressure microfluidization on the morphology, structure and rheology of sweet potato starch

In order to appropriately improve the performance of sweet potato starch and expand its industrial application, sweet potato starch was modified by high pressure microfluidization (HPM) technology in this paper. The influence of HPM on sweet potato starch was studied by SEM, PLM, XRD, FTIR, DSC and rheology. The results showed that the mechanical forces generated by HPM could penetrate into the starch granules, resulting in constant changes in structure and properties of the starch granules. At 80 MPa, recrystallization phenomenon occurred inside starch granules, and the structure became more compact. 120–160 Mpa of HPM caused the breakage of the particles and the disordered arrangement of starch molecules, the relative crystallinity reduced to 25.46%, ΔH reduced to a minimum of 7.107 J/g, and the rheological behavior of starch gel changed significantly. It could be seen that HPM had significant mechanochemical effects on the sweet potato starch granules.

Effect of high-pressure microfluidization on nutritional quality of carrot (Daucus carota L.) juice.

In this study, the effect of high-pressure microfluidization on the colour and nutritional qualities of the orange carrot juice was investigated. The juice was processed at three different pressures (34.47MPa, 68.95MPa and 103.42MPa) with three different passes (1, 2 and 3 passes). After that, total phenolic content (TPC), antioxidant activity, carotenoids, color properties, and total soluble solids content of the processed carrot juice were evaluated. As a result, no specific trends in TPC and antioxidant activity of the juice were observed through the variations of processing conditions. However, microfluidization significantly (p < 0.05) improved the carotenoids content in carrot juice. With increasing number of pass, concentrations of β-carotene and lutein had increased significantly. Similarly, increasing process pressure initially increased carotenoid content significantly (up to 68.95MPa), further increase pressure to 103.42MPa did not cause significant changes in carotenoid concentration. Furthermore, color properties such as lightness, redness, yellowness, and chroma value were reduced significantly with the increase of pressure and the number of passes. The results indicated that high-pressure microfluidization could be used as a novel alternative nonthermal technology to heat pasteurization to improve the color and nutritional qualities in orange carrot juice, resulting in a desirable, high-quality juice for consumers.

Microfluidization as a honey processing proposal to improve its functional quality

The effect of high pressure microfluidization on the hydroxymethylfurfural content, glucose and fructose, phenolics, antioxidant activity, diastase number, colour and viscosity were evaluated as a novel alternative to thermal processing. Samples were treated in a microfluidizer, and the effect of pressure (34–69 MPa), cycles (1–5) and type of interaction chamber (Y-Z-type and Z-type) were determined. Higher phenolic content and antioxidant activity values than control honey was obtained for all treatments (9.80–53.89%, 7.5–37.2% respectively). The viscosity of honey was reduced in all the microfluidization conditions, being the type interaction chamber and cycles of operation the significative effects (p < 0.05). Operating with Z-type chamber the quality parameters such as hydroxymethylfurfural and diastase activity were preserved up to 93%. The Y-Z-type chamber and high pressures (69 MPa) promote and facilitate the Maillard reactions, reflected in a decrease of glucose and fructose content, a slightly increase of HMF content and ΔE* values.

Effect of high pressure microfluidization on the crystallization behavior of palm stearin - palm olein blends.

Moderate and high microfluidization pressures (60 and 120 MPa) and different treatment times (once and twice) were used to investigate the effect of high-pressure microfluidization (HPM) treatment on the crystallization behavior and physical properties of binary mixtures of palm stearin (PS) and palm olein (PO). The polarized light microscopy (PLM), texture analyzer, X-ray diffraction (XRD) and differential scanning calorimetry (DSC) techniques were applied to analyze the changes in crystal network structure, hardness, polymorphism and thermal property of the control and treated blends. PLM results showed that HPM caused significant reductions in maximum crystal diameter in all treated blends, and thus led to changes in the crystal network structure, and finally caused higher hardness in than the control blends. The XRD study demonstrated that HPM altered crystalline polymorphism. The HPM-treated blends showed a predominance of the more stable β' form, which is of more interest for food applications, while the control blend had more α- and β-form. This result was further confirmed by DSC observations. These changes in crystallization behavior indicated that HPM treatment was more likely to modify the crystallization processes and nucleation mechanisms.

Effect of High Pressure Microfluidization on Secondary Structure of Wheat Gluten in Different Solvents

Far-UV circular dichroism (CD) spectroscopy was used to study the conformation of wheat gluten protein treatmented by dynamic high pressure microfluidization (DHPM), acid treatment and its comprehensive treatment in two solvents. The results showed, the secondary structure of control sample are mainly consist of α-helix and random-coil in phosphate-buffered saline (PBS) and phosphate buffered solution with SDS(SDS), the secondary structure of control sample are mainly consist of β-Sheet and random-coil. The CD data also showed that SDS interacts with the gluten protein and modifies the protein conformation, which switched the conformation from α-helix and β-Turn to β-sheet and random-coil. However, the CD analysis also indicated that some of the ordered structures of α-helix, β-Turn and β-sheet were destroyed and converted random-coil coped with acid in two solvents, in other words, the acid treatment can directed change the secondary structure. Furthermore, the effect of comprehensive treatment (DHPM plus acid) is not equal to the simple sum of the individual treatment effect.

Using high pressure microfluidization to improve physical properties and lycopene content of ketchup type products

This study evaluates the effects of high pressure microfluidization of ketchup mixes on the physical properties and lycopene content. During the processing the pressure level ranged between 200 and 2000bar, while the number of passes was kept constant. When the treatment pressure was increased from 200 to 1200bar, the yield stress, elastic modulus, storage modulus, and Bostwick consistency values of the ketchup samples improved. However, over-processing was observed for the samples treated at 1600 and 2000bar. Light and scanning electron microscope images were used as visual means to observe microfluidization induced structural changes. Colloidal stability measurement showed that increasing microfluidization pressure improved physical stability of the samples. Reducing the size and changing the nature of tomato solids through high pressure microfluidization also increased the detectable lycopene levels of the ketchup samples.

The effect of high pressure microfluidization on the structure and length distribution of whey protein fibrils

The effect of high pressure microfluidization on native β-lactoglobulin (β-lg) or whey protein isolate (WPI), both before and after heat-induced protein fibril formation at pH 2.0, was investigated using atomic force microscopy (AFM), shear birefringence, reversed phase-high pressure liquid chromatography, attenuated total reflectance–Fourier transform infrared spectroscopy and fluorescence spectroscopy. The morphology and length distribution of the fibrils were determined using AFM and flow-induced birefringence, respectively. High pressure (≥50 MPa) microfluidization treatment of β-lg induced ∼30% protein denaturation, accompanied by changes in secondary structure. Fibrils formed from high pressure treated β-lg or WPI were similar in length to fibrils formed from non-pressure treated proteins. High pressure (≥50 MPa) microfluidization of fibrils formed from β-lg or WPI resulted in their breakup into more uniformly sized and much shorter fibrils. Microfluidization pressures of up to 170 MPa resulted in slightly shorter fibrils but did not completely dissociate them.

Effect of High Pressure Microfluidization on Microstructure of Mozzarella Cheese

Microstructure was compared in low-fat and full-fat mozzarella cheeses prepared from milk homogenized by microfluidization at various temperatures and pressures. Milk heated to 10, 43, or 54°C and containing 1.0 or 3.2 g fat/100 g fluid milk was homogenized at 34, 103, or 172 MPa prior to cheesemaking. Scanning electron microscopy was performed after 1 d and 6 wk of storage at 4°C. The micrographs showed that relatively large fat globules were dispersed throughout the casein matrix in each of the cheeses made from milk homogenized at 10°C, and in each of the nonhomogenized controls. As expected, fat globules were much smaller in the cheeses made from milk homogenized at the higher pressures. Increasing the milk temperature also caused the globule size to decrease since the fat became liquid and more easily fragmented. The results indicate that both homogenization temperature and pressure affect development of microstructure in mozzarella cheese.