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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 42 (1977), S. 0 
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Insoluble fish protein concentrate (FPC) was solubilized by the proteolytic enzyme trypsin in batch, semi-batch and continuous flow membrane raactors. Parametric studies were carried out on the batch system to determine the effects of temperature, pH, enzyme to substrate ratio, and initial substrate concentration on the kinetics of solubilization. The optimum conditions for the batch process were 50°C and pH 9. Product inhibition was found to be significant. At 40°C, pH 9, an initial substrate concentration of 50 mg/cm3, and a trypsin to substrate ratio of 0.001 (w/w), 61 per cent of the initial substrate was solubilized within one hour. In the semi-batch experiments, the effects of temperature, pH, enzyme to substrate ratio, and prewashing of substrate were investigated. The optimum operating conditions for an initial substrate concentration of 50 mg/cm3 were 50°C and pH 8.8 with a trypsin to substrate ratio of 0.002 (w/w). After 4 hr of operation under the conditions stated above, 85% of the total amount of initial solid was dissolved. 62% of the initial nitrogen content appeared in the permeate.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 41 (1976), S. 0 
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Permeate (pH 6.71) from ultrafiltration of skim milk was blended 1:1 and 2:1 (w/w) with whey (pH 4.68) resulting from production of cottage cheese from skim milk retentate. Blends were condensed to 50% solids and used to increase. solids concentration of skim milk by up to 2%. With increasing solids addition, skim milk pH declined and ash, lactose, and protein concentrates (wet weight basis) increased. The ratio of undenatured whey protein nitrogen:casein nitrogen increased by 50% in milk fortified with 2% added solids provided by condensed 2:1 permeate:whey blend. Bacteriological quality of fortified samples was satisfactory. Sensory evaluations indicated that skim milk fortification limits using 1:1 and 2:1 permeate:whey blends were 0.5 and 1.0% added solids, respectively.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 41 (1976), S. 0 
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Ultrafiltration of skim milk was conducted at 4.4, 21.0 and 49.0°C to provide retentates for cottage cheese trials. Fractionation at 21.0 and 49.0°C improved initial permeation flux rate (PR) by 50 and 300%, respectively, over that observed at 4.4°C. Rates of decline of PR de creased with increasing temperature. Retentate ratios of undenatured whey protein nitrogen:casein nitrogen (CN) and proteosepeptone:CN were unchanged during ultrafiltration whereas nonprotein nitrogen:CN declined at each temperature. Calcium concentration of permeate was 1–2% less at 49.0 than 4.4°C because of increased calcium concentration of retentate at higher temperature. Large curd, creamed cottage cheese was prepared successfully from each retentate, cooking temperature and/or time being reduced because of initially firmer curd. Intermediate temperature (21.0°C) processing induced rapid microbial proliferation after 〉 2 hr. The utility of ultrafiltration as a preconcentration step for continuous cottage cheese production is discussed.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 43 (1978), S. 0 
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The enzymatic solubilization of an insoluble alfalfa protein fraction was studied in a batch reactor and in a continuous flow semi-batch membrane reactor. The “white” cytoplasmic protein fraction obtained by heat precipitation was solubilized using the proteolytic enzyme trypsin. Batch studies were carried out at pH 7.7 with a trypsin to substrate ratio of 2 x 10m-3 (by weight). At 27, 37 and 47°C the hydrolysis reaction was found to be first-order in substrate concentration. The activation energy was 23.25 kcal. At 47°C the conversion level was 97% after 4 hr. For the membrane reactor system, the effects of the variables pH, temperature, substrate concentration, and trypsin to substrate ratio were evaluated with the aid of factorial design methods. The optimum operating conditions for the membrane reactor studies were 47°C at pH 7.7 with a trypsin to substrate ratio of 4 x 10-3 at a 0.5% solids concentration level. The hydrolysis process was enhanced if the reactor was operated in a washout mode prior to the addition of enzyme suggesting that soluble low molecular weight inhibitors were washed out of the reactor with the permeate. 55% of the total amount of insoluble starting material appeared as products in the permeate after 4 hr of operation under the conditions stated above.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 69 (2004), S. 0 
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: : Interesterification (acidolysis) of fully hydrogenated soybean oil (melting point = 69.9 °C) with conjugated linoleic acid (CLA) was carried out in a batch reactor at 75 °C. Lipases from Candida antarctica, Rhizomucor miehei, Pseudomonas sp., and Thermomyces lanuginosus were used at 5% (wt/wt) of the total substrate load. The lipase from Rhizomucor miehei produced the fastest reaction rates, and the greatest extent of incorporation of CLA residues in acylglycerols was achieved in 12 h. Lipases from C. antarctica and T. lanuginosus produced slower initial rates, and maximum extents of incorporation of CLA residues were achieved in 24 h. The lipase from Pseudomonas sp. produced the slowest initial rate. The corresponding maximum extent of incorporation was reached in 48 h. Differential scanning calorimetry analysis of the triacylglycerol (TAG) fractions produced by C. antarctica, R. miehei, and T. lanuginosus lipases after purification by solid phase extraction showed little variation in melting point (60.4 °C, 62.8 °C, and 60.1 °C, respectively). By contrast, the corresponding TAG fraction produced by the Pseudomonas sp. lipase melted at 48.4 °C. The positional distribution of the TAGs produced by the lipase from Pseudomonas sp. differed appreciably from those produced by the other enzymes.
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  • 6
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 9 (1975), S. 487-499 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Surface modification of cellulose acetate dialysis membranes was carried out by 60Co radiation induced graft copolymerization of the hydrogel, hydroxyethyl methacrylate (HEMA). The degree of grafting was controlled by varying the HEMA monomer concentration in the grafting solution and the radiation dose. A continuous flow platelet adhesion test was designed which allows testing under conditions more closely approximating hemodialysis than other small scale in vitro tests. Platelet adhesion on treated membranes fell substantially with increasing surface HEMA concentration. The presence of HEMA on the membrane surface did not affect the membrane activated clotting times significantly.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 429-437 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effects of temperature on the hydrolysis of lactose by immobilized beta-galactosidase were studied in a continuous flow capillary bed reactor. Temperature affects the rates of enzymatic reactions in two ways. Higher temperatures increase the rate of the hydrolysis reaction, but also increase the rate of thermal deactivation of the enzyme. The effect of temperature on the kinetic parameters was studied by performing lactose hydrolysis experiments at 15, 20, 25, 30, and 40°C. The kinetic parameters were observed to follow an Arrhenius-type temperature dependence. Galactose mutarotation has a significant impact on the overall rate of lactose hydrolysis. The temperature dependence of the mutarotation of galactose was effectively modelled by first-order reversible kinetics. The thermal deactivation characteristics of the immobilized enzyme reactor were investigated by performing lactose hydrolysis experiments at 52, 56, 60, and 64°C. The thermal deactivation was modelled effectively as a first order decay process. Based on the estimated thermal deactivation rate constants, at an operating temperature of 40°C, 10% of the enzyme activity would be lost in one year.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 438-446 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The hydrolysis of lactose by immobilized β-galactosidase was studied in a continuous-flow capillary bed reactor operating at 30°C. Solutions containing 50, 100, and 150 g lactose and 0.5 g sodium acetate/L were fed to the reactor. Lactose conversions ranging from 24% to greater than 99% were achieved at reactor space times ranging from 0.06 to 6.3 min. These conversion data were successfully modeled in terms of a plug flow reactor model and a form of Michaelis-Menten kinetics which included competitive inhibition by both the alpha and beta forms of galactose.
    Additional Material: 8 Ill.
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  • 9
    Publication Date: 1975-10-01
    Print ISSN: 0034-6748
    Electronic ISSN: 1089-7623
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
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  • 10
    Publication Date: 1981-06-01
    Print ISSN: 0034-6748
    Electronic ISSN: 1089-7623
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
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