Dynamic high pressure microfluidization (DHPM): Physicochemical properties, nutritional constituents and microorganisms of yam juice

Dynamic high pressure microfluidization (DHPM) is considered an emerging and promising technique for the continuous production of fluid foods. This study measured the effect of DHPM on yam juice. After DHPM processing, the content of total soluble solids (TSS), turbidity, flavonoid and non-enzymatic browning was significantly decreased, with the biggest drops being 35.5, 86.2, 20.7, and 66.7%, respectively. Moreover, the average particle size was decreased from 1 944 nm to 358 nm, which showed a strong positive correlation with turbidity. The reduction coefficients and electric conductivity of Escherichia coli, Saccharomyces cerevisiae and Lactobacillus plantarum were increased significantly after DHPM processing. Combined with morphological analysis, DHPM processing had good bactericidal effects on E. coli and S. cerevisiae. These results provided reference values for the application of DHPM technology in the development of yam juice.

Physical, chemical and rheological properties of pitomba (Talisia esculenta) seed starch and its application as a thickener and stabilizer in ketchup

The present study aimed to characterize the physical, chemical and rheological properties of starch extracted from pitomba seeds and verify the influence of its addition on the syneresis and viscosity characteristics of ketchup during storage, compared to maize starch. Extraction was performed by grinding the seeds in sodium metabisulfite solution (0.2%) followed by drying at 50 ºC. ketchups were formulated with the addition of 0.5 and 1% pitomba starch, 0.5 and 1% maize starch and a control formulation. Starch showed low percentages of protein, ashes and lipid, starch purity of 77.78%, amylose of 19.25%, apparent density of 0.46 g/cm3 and compact density of 0.66 g/cm3. The starch pastes showed pseudoplastic behavior and imparted significant viscosity, usable in increasing the consistency of fluid foods. Ketchups formulated with addition of pitomba starch showed reduction of syneresis during storage, and the 1% starch concentration can slow down the syneresis process in ketchup at temperatures of 7 and 25 °C, similar to the stabilizing capacity of maize starch. Ketchup viscosity increased with the addition of pitomba and maize starches, but the highest apparent viscosities were obtained in ketchup with addition of pitomba starch during storage

Effects of Rheological Parameters of a Viscoplastic Fluid on Peristaltic Pumping in a Cylindrical Tube

In this paper, we study theoretically the peristaltic transport of a generalized four-parameter plastic fluid in a circular cylindrical tube. The present fluid model is presented for the rheological characterization of inelastic fluid foods. Long wavelength and low Reynolds number approximations are taken into account to get solution. The effects of embedded parameters on pressure rise, frictional force and especially on the mechanical efficiency have been numerically displayed and physically discussed.

Use of Ultra High Pressure Homogenization to sterilize grape must

Ultra-High Pressure Homogenization Sterilization (UHPHS) allows the sterilization of fluid foods at low temperatures or even in refrigeration. UHPHS is a continuous technique that allows to process 10,000 L/h with a single pump working at 300 MPa with an imbalance of 1 MPa (Ypsicon EP2409583). During the process, fluid temperature increases less than 5 ∘C. The technique is sensory gentle not affecting molecules formed by covalent bonds so aroma and pigments are unaltered. During the process of white musts, the complete elimination of yeasts, bacteria and spores can be achieved and the must may remain unfermented for several months-years if stored in amicrobic conditions. The technique is also effective in the destruction of polyphenol oxidase (PPO) enzymes. Final size particle is 100–300 nm allowing to increase the availability of yeast assimilable nitrogen and opens the opportunity to nano-encapsulate flavours. Destruction of PPOs and elimination of microorganisms help to reduce sulphites in wines. UHPHS facilitates the use of new biotechnologies such as the use of non-Saccharomyces yeasts and yeast-bacteria co-inoculations by enabling a better implantation of the starters in absence of competition with wild grape microorganisms.