Enzymatic hydrolysis of food proteins generally results in profound changes in the functional properties of the proteins treated. Protein hydrolysates may therefore be expected to fulfil certain of the food industry's demands for proteins with particular, well-defined functional properties. A wide-spread use of protein hydrolysates in food requires, however, a careful control of the taste and functionality of the protein during its hydrolysis and subsequent processing to obtain a reproducible product quality.The composition of a protein hydrolysate is conveniently described by the degree of hydrolysis (DH), which is defined as the percentage of peptide bonds cleaved (1). The average peptide chain length (PCL), measured in number of amino acid residues, can be shown to be related to DH by the following equation: DH -<ΡΞΓ5Ξ?x (1 + l^W' x 100% (1) where PCL O is the average peptide chain length of the intact pro tein. Both PCL and PCL O are the number-average peptide chain lengths. In most cases PCL O is large, PCL O » PCL and (1) approaches DH -±22» (2) PCL V 1Many workers have studied the influence of enzymatic hydrolysis on the functional properties of various food proteins, and much of this work has recently been reviewed by Richardson (2). However, there seem to be very few reports which quantitatively relate functionality to parameters which characterize the protein hydro lysates per se (e.g. molecular weight). Ricks et al. (3) examined the solubility and taste of a number of pure proteins (denatured pepsin, lactoblobulin, α-S 1 -, κ-, and β-casein) hydrolysed with 0-8412-0478-0/79/47-092-125$05.50/0
Enzymes have effectively assisted the development and improvement of modern household and industrial detergents. The major classes of detergent enzymes-proteases, lipases, amylases, and cellulases-each provide specific benefits for application in laundry and automatic dishwashing. Historically, proteases were first to be used extensively in laundry detergents. In addition to raising the level of cleaning, they have also provided environmental benefits by reducing energy consumption through shorter washing times, lower washing temperatures, and reduced water consumption. Today proteases are joined by lipases and amylases in improving detergent efficacy especially for household laundering at lower temperatures and, in industrial cleaning operations, at lower pH levels. Cellulases contribute to overall fabric care by rejuvenating or maintaining the new appearance of washed garments. Enzymes are produced by fermentation technologies that utilize renewable resources. JSD 1, 555-567 (1998).Over the years, enzymes have been an important factor in the development and improvement of detergent products. In laundering, dishwashing, and in industrial and institutional (I&I) cleaning, they have contributed to shortening washing times, reducing energy and water consumption by lowering washing temperatures, providing environmentally friendlier wash-water effluents, lowering pH levels in wash liquors, and providing fabric care. Enzymes themselves are environmentally attractive since they are derived from renewable sources. They are also highly space-efficient and are thus of particular advantage in concentrated detergent formulations. Developments in genetic and protein engineering have contributed to long-needed improvements in the stability, economy, specificity, and overall potential of industrial enzyme products. FIG. 3. Example of a pH-stat trial on EMPA 117 swatches-European detergent. Reaction conditions: temperature, 40°C; concentration, 6.5 g EMPA 117 in 800 g wash; detergent, 4 g/L European (bleach-containing) detergent, pH 9.8; water hardness, 18°dH; enzyme, Savinase 12 T; activity dosage, 0-0.3 kNPU/L. See Figure 2 for abbreviations. FIG. 4. The pH-stat hydrolysis curve for a hemoglobin in an automatic dishwashing detergent with Savinase. DH, degree of hydrolysis. Reaction conditions: temperature, 50°C; concentration, 0.5% protein (N × 6.25); detergent, 4.5 g/L European dishwashing detergent (pH 10.3); enzyme, Savinase 16 L; activity dosage, 0.75 kNPU/L. See Figure 2 for other abbreviation.
Large‐scale dispersion in a sandy unconfined aquifer in Denmark was studied by simulating subsurface transport of environmental tritium. Subsurface transport included transport in a moderately deep unsaturated zone and in a relatively long cross section of the aquifer. The tritium data from the site enabled a four‐step modeling analysis comprising (1) estimation of tritium content in the infiltration water, (2) transport in the unsaturated zone, (3) estimation of flux‐averaged tritium concentration in the recharge water, and (4) transport in the groundwater zone. The groundwater model simulations were sensitive to the longitudinal and transverse dispersivity parameters, αL and αr, as a set of parameters, but a model sensitivity analysis showed that it was not possible to identify a unique set of parameter values. A likely range of variation for the two parameters could be identified: (αL, αT); ∈ [(1 m, 0.005 m); (10 m, 0.0 m)] the two parameters being interdependent in that an increase in αL results in a decrease in αT and vice versa. The reported dispersivities represent a scale of 1000 m, the approximate travel distance from the water table to the observation wells. If the estimated αL can be regarded as being of intermediate reliability following earlier defined criteria, the range or the representative set of values then represent the largest scale of earlier reported values. Including our range of αL in the set of reported dispersivities suggests that αL does not increase indefinitely with scale.
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