Digestion conditions

A schematic diagram of the liquid solvent extraction process is illustrated in Figure 1. Where the production of liquid hydrocarbons is the main objective an hydrogenated donor process solvent is used, whereas in the production of needle coke this is not necessary and a coal derived high boiling aromatic solvent may be used (e.g. anthracene oil). An essential economic requirement of the process is that a high extraction yield of the coal is obtained and this will depend upon the coal used and the digestion conditions. 

Digestion conditions 400°C 60 minute residence time Coal solvent ratio 1 3... 

Digestion conditions nominally 400 C with 60 min residence time Solvent anthracene oil... 

In this report our original procedure (7.) is described. Then the published in vivo - in vitro comparison experiments (8) are briefly summarized and subsequent investigations on in vitro digestion conditions and methods for fractionation of calcium from digests are reported. 

When the estimates of bioavailability were compared ( ), in vivo absorption was higher than in vitro solubility for two of the foods We had expected absorption to be less than solubility due to physiological factors (lt9). Thus, this surprising result led to the reexamination of in vitro digestion conditions which is reported in this paper. 

The pancreatic digestion conditions studied included pH, the method of pH control, and bile salts mixture and concentration. In addition, experiments were run to determine if mineral solubility was affected by enzymatic activity, or only by pH-induced solubility changes. 

Choice of Potential Bioavailability Criterion. It is usually assumed that calcium must be soluble and probably ionized in order to be available for absorption ( ). For the in vitro procedure, as a first approximation we chose calcium solubility after centrifugation at 18,000 x g as the measure of potential bioavailability (Figure 1). We assumed that this would probably overestimate the available calcium and later work based on fractionation might define the bioavailable calcium more precisely. The data in Table IV illustrate how the choice of criterion for "solubility" could affect the in vitro estimate of potential availability, even if in vitro conditions closely resembled in vivo conditions. Since our in vitro criterion unexpectedly underestimated calcium bioavailability for two of the three foods in the direct in vivo - in vitro comparison (8), it was necessary to determine the in vitro digestion conditions which might be limiting solubility before addressing the choice of appropriate criterion. 

Digestion Conditions. Peptic conditions were not emphasized since calcium solubility is high at the peptic stage (Table I) and chyme release to the duodenum is more dependent on particle size than completeness of digestion (23>24). 

To determine how controlled manipulation of digestion conditions influences the distribution of calcium among possible ligands from a food or meal. 

Table 25.1 Digestion conditions for mushroom samples in the microwave digestion system...

For digestion, CEM Mars 5 microwave closed system was used in this study. 0.5 g of samples was digested with 5 luL of HNOj (65%) and 2 mL of (30%) in a microwave digestion system for 17 min and final diluted to 25 ruL with deionized water. A blank digest was carried out in the same way. Digestion conditions are given in Table 25.1. 

Wang, L. Pan, H. Smith, D.L. Hydrogen exchange-mass spectrometry. Optimization of digestion conditions. Mol. Cell. Proteomics 2002, 1, 132-138. 

Semenova M.G., Belyakova, L.E., Polikarpov, Yu.N., Antipova, A.S., Anokhina, M.S. (2008). Utilization of sodium caseinate nanoparticles as molecular nanocontainers for delivery of bioactive lipids to food systems relationship to the retention and controlled release of phospholipids in the simulated digestion conditions. In Williams, P.A., Phillips, G.O. (Eds). Gums and Stabilisers for the Food Industry 14, Cambridge, UK Royal Society of Chemistry, pp. 326-333. 

Pressurised liquid extraction was applied to treat biological materials. Seven variables were studied simultaneously to find the best digestion conditions. Different variables were critical for different sets of metals... 

Very interesting additional data come from studies on poly 3-iso-adenylic acid (nonsubstrate) 440) and the unusual purines related to formycin (substrates), F, 441, 443). The activity of the enzyme on these compounds is much higher than that toward the normal purines and is comparable to that toward the pyrimidines. Ikehara et al. 441) have reported the action of RNase on poly (F-C), poly (F-U), and poly (F-G) FpUp, FpCp, and GpFp were obtained. With more enzyme the first two yielded F > p and eventually 3 -FMP. Under the digestion conditions used poly (A-G) was not attacked at all. 

Sripathy, N. V., Sen, D. P., Lahiry, D. P., Sreenivasan, A., and Subrahmanyan, V. 1962. Fish hydrolysates. II. Standardization of digestion conditions for preparation of hydrolysates rich in peptones and proteoses. Food Technol., 141-142. 

The pulping (cooking) process traditionally was performed on a batch basis in a large pressure vessel called a digester. Conditions vary depending upon the type of wood being pulped and the quality of end product desired. Typical conditions for kraft cooking are listed in Table 28.3. 

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