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71.
Pectinesterase (EC 3.1.1.11) was extracted from potato (Solanum tuberosum var. Russet Burbank) tissue and purified 9.6-fold by ammonium sulphate precipitation and chromatography on Sephadex G-100. The enzyme preparation thus obtained has a molecular weight of 25,000, an apparent Km of 0.09% for citrus pectin and a pH optimum of 7.5. NaCl is a positive modulator of the enzyme. The energy of activation of the enzyme is 6200 calories. A Q10 of 1.33 is observed in the temperature range of 25 to 45°C, and the optimum temperature for the enzyme is 55°C. 相似文献
72.
Sharon M Pradhan D Zacharia R Puri V 《Journal of nanoscience and nanotechnology》2005,5(12):2117-2120
Microwave absorption (8 GHz to 12 GHz) studies have been made with carbon nanomaterials for the first time. Carbon nanomaterials are synthesized by the pyrolysis of camphor. It is observed that film of carbon prepared under certain synthetic condition, can absorb microwave of either some specific wavelengths e.g., 9.5 GHz and 11.5 GHz or full range from 8-12 GHz to the extent of 20 dB depending upon their preparation condition. Carbon nanobeads seems to absorb the microwave in the range of 8-12 GHz. 相似文献
73.
A.B. Puri B. Bhattacharyya 《The International Journal of Advanced Manufacturing Technology》2005,25(3-4):301-307
A white layer is considered a major flaw on a workpiece surface machined with wire-cut electrical discharge machining (WEDM). In this paper, an attempt has been made to model the white layer depth through response surface methodology (RSM) in a WEDM process comprising a rough cut followed by a trim cut. An experimental plan for rotatable central composite design of second order involving four variables with five levels has been employed to carry out the experimental investigation and subsequently to establish the mathematical model correlating the input process parameters with the response. Pulse on time during rough cutting, pulse on time, wire tool offset, and constant cutting speed during trim cutting are considered the dominant input process parameters whilst the white layer depth is the response. An insignificant lack of fit term indicated a curve with a good fit. Also, an extensive analysis of the influences of all the individual input parameters on the response has been carried out and presented in this research study. 相似文献
74.
P. S. Puri 《Journal of the American Oil Chemists' Society》1978,55(12):865-869
Two empirical models are proposed to correlate the amount of trans-isomers formed during the partial hydrogenation of oils
and fats as a function of the degree of hydrogenation and process variables. From minimal experimental data, constants for
these models can be obtained and used to interpolate or extrapolate the trans-isomer data to predict the amount of trans-isomers
formed during a partial hydrogenation or to select processing conditions for a desired amount of trans-unsaturation. The application
of these models has been demonstrated using hydro-genation data for soybean and rapeseed oils. 相似文献
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Pullulan, which is comprised of glucose units, is a simple linear polysaccharide produced by Aureobasidium pullulans. Pullulan has long been used in various applications such as blood plasma substitutes, food additives, adhesive additives, flocculants, and even environmental pollution control agents. Mathematical models of biomass, pullulan, and sucrose profiles during fermentation not only provide information about the kinetic-metabolic nature of pullulan, but also facilitate the control and optimization of pullulan production. In this study, several models were modified and tested in order to describe biomass, pullulan, and sucrose profiles during batch fermentation using a color variant strain of A. pullulans. The results demonstrated that the modified Gompertz model can serve as a universal equation to fit biomass production, pullulan production, and sucrose consumption. Furthermore, validation of this modified Gompertz model indicated that biomass (slope = 1.00, R2 = 0.991), pullulan (slope = 1.10, R2 = 0.991), and sucrose (slope = 0.96, R2 = 0.991) were all predicted accurately. 相似文献
79.
The physicochemical and pasting properties of pigeon pea and rice starches were studied to assess their suitability for noodle making. Amylose content, solubility and freeze thaw stability of pigeon pea starch were significantly higher than those of rice starch (p < 0.05). The pasting properties of peak viscosity, final viscosity, breakdown and set back showed higher values for pigeon pea starch, whereas hot paste viscosity and pasting temperature were higher for rice starch. Rice starch noodles revealed less cooking time (4 min) and less percent solids loss, whereas pigeon pea starch noodles had higher cooking time (12 min), higher percentage of water absorbed during cooking, more hardness and cohesiveness. Rice starch noodles scored higher for their transparency and slipperiness over pigeon pea starch noodles. Blending of pigeon pea starch with rice starch had significant effects on the cooking and sensory quality of noodles. Among starch blends, 70:30 blend of the pigeon pea and rice starches respectively resulted in good quality of noodles especially in terms of their higher transparency, slipperiness, overall acceptability and cohesiveness values. Blending of pigeon pea starch with 30% rice starch could produce noodles with superior quality as compared to native pigeon pea and rice starch noodles. 相似文献
80.
Kuan-Chen ChengAli Demirci Jeffrey M. CatchmarkVirendra M. Puri 《Journal of food engineering》2011,103(2):115-122
Pullulan fermentations by Aureobasidium pullulans with various initial ammonium ion concentrations were evaluated in a 2-L bioreactor. The results demonstrated that A. pullulans produced highest pullulan (23.1 g/L) when the initial ammonium sulfate was 7 at 5 g/L. The purity of produced pullulan was 94.6%. Seven gram per liter of ammonium sulfate produced more biomass due to the higher level of nitrogen source, but the pullulan-degrading enzyme activity was detected after the depletion of sucrose, which reduced pullulan concentration. From the results of fed-batch fermentation, addition of 10 g/L of sucrose suppressed A. pullulans from producing pullulan-degrading enzyme. Additionally, the modified-Gompertz equation demonstrated its generality to fit all pullulan production, biomass production, and sucrose consumption curves at three ammonium sulfate levels. After incorporating the degrading factor, a re-modified-Gompertz equation was obtained that can adequately describe the decrease of pullulan at the late fermentation stage. 相似文献