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Chapter 1: Theory of endo-1, 4-Beta-D-Xylanase Assay Procedure
Chapter 2: Buffers & Reagents
Chapter 3: Assay Procedure
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|Content:||200 Tablets or 1,000 Tablets|
|Stability:||> 10 years under recommended storage conditions|
|Substrate For (Enzyme):||Protease|
|Reproducibility (%):||~ 5%|
High purity dyed and crosslinked Protazyme OL tablets for the measurement of enzyme activity, for research, biochemical enzyme assays and in vitro diagnostic analysis.
endo-Protease test tablets. Containing AZCL-Collagen.
Please note the video above shows the protocol for assay of endo-xylanase using xylazyme tablets. The procedure for the assay of protease using Protazyme OL Tablets is equivalent to this.
Enzyme purity and activity in fibre determinations.
McCleary, B. V. (1999). Cereal Foods World, 44(8), 590-596.
Dietary fiber is mainly composed of plant cell wall polysaccharides such as cellulose, hemicellulose, and pectic substances, but it also includes lignin and other minor components (1). Basically, it covers the polysaccharides that are not hydrolyzed by the endogenous secretions of the human digestive tract (2,3). This definition has served as the target for those developing analytical procedures for the measurement of dietary fiber for quality control and regulatory considerations (4). Most procedures for the measurement of total dietary fiber (TDF), or specific polysaccharide components, either involve some enzyme treatment steps or are mainly enzyme-based. In the development of TDF procedures such as the Prosky method (AOAC International 985.29, AACC 32—05) (5), the Uppsala method (AACC32-25) (6), and the Englyst method (7), the aim was to remove starch and protein through enzyme treatment, and to measure the residue as dietary fiber (after allowing for residual, undigested protein and ash). Dietary fiber was measured either gravimetrically or by chemical or instrumental procedures. Many of the enzyme treatment steps in each of the methods, particularly the prosky (5) and the Uppsala (6) methods are very similar. As a new range of carbohydrates is being introduced as potential dietary fiber components, the original assay procedures will need to be reexamined, and in some cases slightly modified, to ensure accurate and quantitative measurement of these components and of TDF. These “new” dietary fiber components include resistant nondigestible oligosaccharides; native and chemically modified polysaccharides of plant and algal origin (galactomannan, chemically modified celluloses, and agars and carrageenans); and resistant starch. To measure these components accurately, the purity, activity, and specificity of the enzymes employed will become much more important. A particular example of this is the mesurement of fructan. This carbohydrate consists of a fraction with a high degree of polymerization (DP) that is precipitated in the standard Prosky method (5,8) and a low DP fraction consequently is not measured (9). Resistant starch poses a particular problem. This component is only partially resistant to degradation by α-amylase, so the level of enzyme used and the incubation conditions (time and temperature) are critical.Hide Abstract
<i>Short communication</i>: Effect of active food packaging materials on fluid milk quality and shelf life.
Wong, D. E. & Goddard, J. M. (2014). Journal of Dairy Science, 97(1), 166-172.
Active packaging, in which active agents are embedded into or on the surface of food packaging materials, can enhance the nutritive value, economics, and stability of food, as well as enable in-package processing. In one embodiment of active food packaging, lactase was covalently immobilized onto packaging films for in-package lactose hydrolysis. In prior work, lactase was covalently bound to low-density polyethylene using polyethyleneimine and glutaraldehyde cross-linkers to form the packaging film. Because of the potential contaminants of proteases, lipases, and spoilage organisms in typical enzyme preparations, the goal of the current work was to determine the effect of immobilized-lactase active packaging technology on unanticipated side effects, such as shortened shelf-life and reduced product quality. Results suggested no evidence of lipase or protease activity on the active packaging films, indicating that such active packaging films could enable in-package lactose hydrolysis without adversely affecting product quality in terms of dairy protein or lipid stability. Storage stability studies indicated that lactase did not migrate from the film over a 49-d period, and that dry storage resulted in 13.41% retained activity, whereas wet storage conditions enabled retention of 62.52% activity. Results of a standard plate count indicated that the film modification reagents introduced minor microbial contamination; however, the microbial population remained under the 20,000 cfu/mL limit through the manufacturer’s suggested 14-d storage period for all film samples. This suggests that commercially produced immobilized lactase active packaging should use purified cross-linkers and enzymes. Characterization of unanticipated effects of active packaging on food quality reported here is important in demonstrating the commercial potential of such technologies.Hide Abstract
Treatments with xylanase at high (90%) and low (40%) water content have different impacts on physicochemical properties of wheat bran.
Santala, O. K., Nordlund, E. A. & Poutanen, K. S. (2013). Food and Bioprocess Technology, 6(11), 3102-3112.
The aim of the work was to elucidate the impacts of treatment with xylanase at high (90%) and low (40%) water contents on the structural and physicochemical properties of wheat bran. The bran treatments at 40% water content, both with and without added xylanase, resulted in a smaller average bran particle size, more changes in bran microstructure, and higher solubilization of polysaccharides than the corresponding treatments at 90%. Also, the water holding capacity of bran (3.6 ± 0.1 g water/g bran dm), determined by Baumann method, decreased more already after 4-h xylanase treatments at 40% (2.4 ± 0.1) than at 90% (2.9 ± 0.2). The solubility of salt-extractable bran proteins decreased during the treatments, especially at 40%, also without added xylanase. Protein aggregation was detected in the SDS + DTT-extractable bran fraction, which also contained small proteins of 10–20 kDa not detectable in the untreated bran. The use of xylanase had only minor effect on bran proteins as compared to the treatments without added xylanase. The results indicate the large role of mechanical shear on the bran properties at 40% water content. The low arabinose/xylose ratio (0.32) in the bran water extract after 24-h xylanase treatment at 40%, however, suggests that the solubilization of arabinoxylan was caused by enzymatic action, and not by mechanical degradation. Arabinose/xylose ratio of the bran water extract decreased similarly during all the treatments, suggesting similar solubilization pattern of arabinoxylan at both water contents. The study showed that bran properties can be significantly modified by adjusting the water content and mechanical energy used in processing.Hide Abstract
Identification and characterization of a bacterial glutamic peptidase.
Jensen, K., Østergaard, P. R., Wilting, R. & Lassen, S. F. (2010). BMC Biochemistry, 11(1), 47.
Background: Glutamic peptidases, from the MEROPS family G1, are a distinct group of peptidases characterized by a catalytic dyad consisting of a glutamate and a glutamine residue, optimal activity at acidic pH and insensitivity towards the microbial derived protease inhibitor, pepstatin. Previously, only glutamic peptidases derived from filamentous fungi have been characterized. Results: We report the first characterization of a bacterial glutamic peptidase (pepG1), derived from the thermoacidophilic bacteria Alicyclobacillus sp. DSM 15716. The amino acid sequence identity between pepG1 and known fungal glutamic peptidases is only 24-30% but homology modeling, the presence of the glutamate/glutamine catalytic dyad and a number of highly conserved motifs strongly support the inclusion of pepG1 as a glutamic peptidase. Phylogenetic analysis places pepG1 and other putative bacterial and archaeal glutamic peptidases in a cluster separate from the fungal glutamic peptidases, indicating a divergent and independent evolution of bacterial and fungal glutamic peptidases. Purification of pepG1, heterologously expressed in Bacillus subtilis, was performed using hydrophobic interaction chromatography and ion exchange chromatography. The purified peptidase was characterized with respect to its physical properties. Temperature and pH optimums were found to be 60°C and pH 3-4, in agreement with the values observed for the fungal members of family G1. In addition, pepG1 was found to be pepstatin-insensitive, a characteristic signature of glutamic peptidases. Conclusions: Based on the obtained results, we suggest that pepG1 can be added to the MEROPS family G1 as the first characterized bacterial member.Hide Abstract
Scouring of flax rove with the aid of enzymes.
Ossola, M. & Galante, Y. M. (2004). Enzyme and Microbial Technology, 34(2), 177-186.
Linen is the yarn or the fabrics made from fibres of the flax plant (Linum usitatissumum), which, like other bast fibre crops, can be grown in moderate climates and needs low input of agrochemicals to give high yields. Before cotton took over as the main plant-derived textile material, linen was one of the most important source of textile fibres. Following a few decades of almost abandonment, flax fibres are being re-evaluated thanks to the unique features of freshness, comfort and elegance of linen apparels, sheets, towels and other household textile items. However, flax processing into yarn essentially still follows traditional methodologies. We have reinvestigated the effects of several well characterized, mostly recombinant, industrial enzymes on raw flax rove (on a pilot scale from four times 1 kg spools up to 130 kg of material) as an alternative to chemical scouring, followed by a single bleaching step and by yarn wet mechanical spinning. After spinning, all relevant yarn parameters were measured and evaluated (e.g., resistance, stretching, percentage of neps, etc.). In the present work, we demonstrate the advantages of scouring with the enzymes tested, used under mild reaction conditions, in comparison with traditional chemical scouring. The decreasing order of effectiveness was: pectinase>xylanase=galactomannanase=protease>lipase>or=laccase. A simple and straightforward scheme of rove biopreparation and bleaching is proposed, followed by wet spinning to yield a high quality linen yarn.Hide Abstract