Browning products activity

The reactions of AChE-biotests results in the red-brown product (Hettchet pigment). The reaction of AChE-biotests on inhibitors can be estimated visually. The residual activity of AChE in biotests after the action of different concentrations of eserine (physostigmine) and proserine (neostigmine) is seen in Fig. 3. 

Stahl and Parliment126 also determined the loss of glucose and proline with time and found that the rate constant at 200 °C for the former was about three times that of the latter (0.633 and 0.227 min-1, respectively). This difference may be partly due to regeneration of the amine and partly due to caramelisation independent of the amine. The activation energies for glucose and proline were 61.5 (14.7) and 86.7 (20.7) kJ (kcal) mol-1, respectively, and that for browning products (A at 300-304 nm) was 112.6 kJ (26.9 kcal) mol-1. 

Low-molecular-mass browning products (< 1 kDa) from ultrafiltered Japanese soy sauce inhibited CCR, but increased GST activity at low concentrations (25 mg per 100 ml), thus showing evidence of a chemopreventive effect in intestinal cells in vitro.293 More than 90% of soy sauce components have molecular masses < 1 kDa. 

Alternating copolymers containing [S(fc)S] building blocks have been obtained [88] from the base-catalysed polyaddition of fc(SH)2 to activated diolefins such as 1,4-butandiol-dimethacrylate and divinyl sulfone (Fig. 5-6) the oily brown products possess olefmic terminal groups. 

In addition to influencing the rate of lipid oxidation via activation of thiol groups and metallo-enzymes, heating milk may also affect oxidation via redistribution of Cu (which migrates to the FGM on heating) and possibly by the formation of Maillard browning products, some of which have metal chelating and antioxidant properties. 

The resulting yellow-brown solution is filtered, and the solid residue is washed with benzene (50 mL). The collected solution is evaporated to dryness under reduced pressure and the solid residue obtained is extracted with pentane (2 X 60 mL). The light-yellow pentane solution is filtered. (As an alternative procedure, the pentane extract is concentrated and chromatographed with pentane on an alumina column, 1 X 20 cm, Merck product, activity II-III.) Reduction of the volume of the solvent, under vacuum, to about 5 mLand cooling to -78 give light-yellow crystals of Ru(C H )(C H8). The yield is 0.225 g (70% based on RuCls 3H2O). Mp, 118-119 . 

Cesium forms simple alkyl and aryl compounds that are similar to those of the other alkah metals (6). They are colorless, sohd, amorphous, nonvolatile, and insoluble, except by decomposition, in most solvents except diethylzinc. As a result of exceptional reactivity, cesium aryls should be effective in alkylations wherever other alkaline alkyls or Grignard reagents have failed (see Grignard reactions). Cesium reacts with hydrocarbons in which the activity of a C—H link is increased by attachment to the carbon atom of doubly linked or aromatic radicals. A brown, sohd addition product is formed when cesium reacts with ethylene, and a very reactive dark red powder, triphenylmethylcesium [76-83-5] (C H )2CCs, is formed by the reaction of cesium amalgam and a solution of triphenylmethyl chloride in anhydrous ether. 

B. 2-Methylcyclopenlane-l,3,5-trione hydrate. A mixture of 200 g. (0.89 mole) of the keto ester prepared above, 910 ml. of water, and 100 ml. of 85% phosphoric acid is healed under reflux for 4 hours and then cooled in an ice-salt bath to —5°. The trione mixed with oxalic acid separates and is collected by filtration and dried under reduced pressure. The dried material is extracted with boiling ether (250-300 ml.) under reflux, and the ethereal extract is separated from the undissolved oxalic acid. The original aqueous filtrate is also extracted with ether in a continuous extractor. The two extracts are combined, and ether is removed by distillation. The crude trione separates as a dark brown solid and is crystallized from ca. 250 ml. of hot water. The once-crystallized, faintly yellow product weighs 95-105 g. (74-82%), m.p. 70-74°. This product is used in the next step without further purification. A better specimen, m.p. 77-78°, which is almost colorless, can be obtained by recrystallization from hot water after treatment with Norit activated carbon. 

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