Kerusakan Partikel Pangan Selama Dalam Pemompaan

ABSTRACT Damage to food particles during pumping was studied using potatoes shaped into cubes, cylinders and spheres. The variables studied included particle size ratio, density ratio, particle volumetric fraction, Reynolds number, Froude number, and Euler number. The results indicated that the particle size ratio, the Reynolds number, the Froude number, and the Euler number significantly affected the broken particle fraction. The effect of the volumetric fraction of particle was found to be significant when it was less than 0.01. The density ratio and the flow direction of liquid did not have significant effects on the particle fractio

Phytochemical Screening of Methanolic Extract and Antibacterial Activity of Active Principles of Hepatoprotective Herb, Eclipta alba

Aerial parts of Eclipta alba are used traditionally for the treatment of several diseases of liver, skin and stomach. Methanolic extract and active principle compound of a well known Indian hepatoprotective herb, Eclipta alba was tested for in vitro antimicrobial studies. It was evaluated using zone of inhibition studies and minimum inhibitory concentration. The extract exhibited activity against all six strains studied. Phytochemical screening of the extract revealed the presence of tannins, flavonoids, coumestans, saponins and alkaloids etc. Ethylacetate fraction and further pure isolated wedelolactone showed enhanced antimicrobial activity. Staphylococcus epidermidis, Staphylococcus aureus and Salmonella typhimurium were most susceptible. Shigella flexneri was the most resistant bacterial strain. These results suggest coumestans/wedelolactone as a promising antimicrobial agent

KINETIKA PELUNAKAN JARINGAN KENTANG SELAMA DALAM PEMANASAN

Kinetics of softening of potato tissue under heat treatment was investigated. Failure stress was found to be expressed by two first order kinetic equationsfast rate phase and slow rate phase. The reaction rate constants of the fast and slow rate phases were found to be described by two Arrhenius equationsone each at low and high temperature ranges. The logarithm of the duration of the fast rate phase was linearly related to the inverse of the temperature

Dimensionless analysis of fluid-to-particle heat transfer coefficients

Average fluid-to-particle heat transfer coefficients were experimentally determined for spherical aluminium particles heated in car☐ymethylcellulose solutions. Two situations were considered: a still panicle immersed in a moving fluid, and a particle rotating in an otherwise stagnant fluid. Fluid flow rate, rotating particle velocity, particle diameter and fluid rheological properties were varied, covering a large range of the generalized Reynolds (0 to 801) and Prandtl (69 to 5358) numbers. Average heat transfer coefficients ranged between 56 and 2612 W/m2K. The results were compared with values predicted by published dimensionless correlations, showing that correlations based on a Fro¨szling-type equation were more adequate. It was found that the contribution due to natural convection should be considered for proper correlation of the results at low Reynolds numbers. The results also show the importance of the fluid velocity profile

Device and Container for Reheating and Sterilization

Long-duration space missions require the development of improved foods and novel packages that do not represent a significant disposal issue. In addition, it would also be desirable if rapid heating technologies could be used on Earth as well, to improve food quality during a sterilization process. For this purpose, a package equipped with electrodes was developed that will enable rapid reheating of contents via ohmic heating to serving temperature during space vehicle transit. Further, the package is designed with a resealing feature, which enables the package, once used, to contain and sterilize waste, including human waste for storage prior to jettison during a long-duration mission. Ohmic heating is a technology that has been investigated on and off for over a century. Literature indicates that foods processed by ohmic heating are of superior quality to their conventionally processed counterparts. This is due to the speed and uniformity of ohmic heating, which minimizes exposure of sensitive materials to high temperatures. In principle, the material may be heated rapidly to sterilization conditions, cooled rapidly, and stored. The ohmic heating device herein is incorporated within a package. While this by itself is not novel, a reusable feature also was developed with the intent that waste may be stored and re-sterilized within the packages. These would then serve a useful function after their use in food processing and storage. The enclosure should be designed to minimize mass (and for NASA's purposes, Equivalent System Mass, or ESM), while enabling the sterilization function. It should also be electrically insulating. For this reason, Ultem high-strength, machinable electrical insulator was used

Impaired Functions of Peripheral Blood Monocyte Subpopulations in Aged Humans

Aging is associated with increased susceptibility to microbial infections, and monocytes play an important role in microbial defense. In this study, we have identified and compared four subpopulations of monocytes (CD14++(high)CD16−, CD14+(low)CD16−, CD14++(high)CD16+, and CD14+(low)CD16+) in the peripheral blood of young and aged subjects with regard to their numbers, cytokine production, TLR expression, and phosphorylation of ERK1/2 in response to pam3Cys a TLR-1/2 ligand. Proportions and numbers of CD14++(high)CD16+ and CD14+(low)CD16+ monocytes were significantly increased, whereas proportions of CD14+(low)CD16− monocytes were decreased in aged subjects as compared to young subjects. In aged subjects, IL-6 production by all four subsets of monocytes was significantly decreased, whereas TNF-α production was decreased in monocyte subsets, except the CD14+(low)CD16− subset. A significantly reduced expression of TLR1 was observed in CD14++(high)CD16+ and CD14+(low)CD16+ monocyte subsets in aged subjects. Furthermore, following pam3Cys stimulation, ERK1/2 phosphorylation was significantly lower in CD14+(low)CD16+, CD14++(high)CD16+, and CD14+(low)CD16− subsets of monocytes from aged subjects. This is the first study of four subpopulations of monocytes in aging, which demonstrates that their functions are differentially impaired with regard to the production of cytokines, expression of TLR, and signaling via the ERK–MAPK pathway. Finally, changes in the number of monocyte subsets, and impairment of TLR1 expression, TNF-α production, and EK1/2 phosphorylation was more consistent in CD16+ monocyte subsets regardless of expression of CD14high or CD14+low, therefore highlighting the significance of further subdivision of monocytes into four subpopulations

Modeling of pulsed electric field processing

Herein, we discuss the modeling of the pulsed electric field (PEF) process, with attention focused on the originally intended application of pasteurization of liquid foods. We review literature on three classes of models. First are the models for electroporation (of molecular scale), derived from physics and physical chemistry considerations, and their extension to probabilistic approaches which treat pore formation as a random process. We discuss the more recent approaches involving molecular dynamics. Then, we consider treatment-chamber and system scale models, which are based on continuum physics approaches, and rely on computational Multiphysics codes for their solution. We then discuss the base assumptions for several modeling studies. Next, we consider models for inactivation kinetics for bacteria exposed to PEF, including the first order, Hulsheger, Peleg and Weibull models. We close with discussions of other models and experimental approaches for model verification and obtaining kinetic parameters from continuous flow PEF systems

Kerusakan Partikel Pangan Selama Dalam Pemompaan

Damage to food particles during pumping was studied using potatoes shaped into cubes, cylinders and spheres. The variables studied included particle size ratio, density ratio, particle volumetric fraction, Reynolds number, Froude number, and Euler number. The results indicated that the particle size ratio, the Reynolds number, the Froude number, and the Euler number significantly affected the broken particle fraction. The effect of the volumetric fraction of particle was found to be significant when it was less than 0.01. The density ratio and the flow direction of liquid did not have significant effects on the particle fractio

Chemical and Bioprocess EngineeringFundamental Concepts for First-Year Students /

XX, 352 p. 208 illus., 84 illus. in color.online