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A high performance liquid chromatographic method for the quantitation of cinnamaldehyde as well as trace amounts of eugenol and piperine in pepper-contaminated cinnamon was developed, using a combination of ultraviolet-diode array (UV) and electrochemical (EC) detectors. The results showed that cinnamaldehyde was detected only with UV detection. The results also demonstrated that while the UV detector failed to detect trace amounts (0.3 to 2.8 mg/L) of eugenol and piperine, the EC detector provided a high resolution for such limited quantities. The limits of detection of piperine and eugenol with EC detector were increased by 40 and 200 times. respectively, compared to those obtained with UV detector. The results indicated that the concentrations of piperine (51.8 mg/L) and eugenol (1.87 mg/L), in the atypical cinnamon, were 33 and 2.5 times, respectively, higher than those present in the non-contaminated products. However, the concentration of cinnamaldehyde (2.60 mg/L) in the atypical cinnamon was close to those found in the noncontaminated products.

The partially purified chlorophyllase, obtained from the algaPhaeodactylum tricornutum, was further purified by preparative native gel electrophoresis. The purification procedure provided the recovery of large amounts of a single purified chlorophyllase fraction. However, the electrophoretic analyses of the purified enzymatic fraction under denaturing conditions demonstrated the presence of two bands with mol wt of 43 ±3 and 46 ±3 kDa. The purification procedure resulted in 2-and 195-fold increases in chlorophyllase activity compared to that of the partially purified and crude enzymatic extracts, respectively. The optimum pH for chlorophyllase hydrolytic activity was found to be 8.0. The optimum incubation time and temperature for the hydrolytic activity of the purified chlorophyllase were found to be 2 h and 31°C, respectively. The optimum concentrations of magnesium chloride and dithiothreitol, used as activators, were 4 and 5 mM, respectively. The addition of individual plant membrane lipids, including phosphatidylcholine, phosphatidylglycerol, and β-carotene, to the reaction media increased the enzyme activity markedly. The purified enzyme fraction displayed preferential specificity toward selective substrates with an order of activity as follows: purified chlorophyllb> purified chlorophylla> partially purified chlorophyll > crude chlorophyll. Diisopropyl fluorophosphate and phytol, respectively, showed noncompetitive and competitive inhibitory effects on chlorophyllase activity with Ki, values of 0.78 mM and 3.75μM, respectively.

Butter fat was interesterified in a cosurfactant-free microemulsion system containing nonionic and ionic surfactants, using commercial lipase obtained fromRhizopus niveus, at different concentrations of surfactant mixtures and hydrophilic-lipophilic balance (HLB) values. The results indicated that the interesterification yield (IY) of lipasecatalyzed interesterified butter fat reached its maximum in the microemulsion system prepared with the surfactant mixture of HLB value of 9, followed by that of HLB value of 10. In addition, increasing concentrations of surfactant mixtures, from 3 to 6 mM, resulted by an increase in the IY. The interesterification of butter fat in the microemulsion prepared with 3 mM of surfactant mixture of HLB value of 10 showed a minimum hydrolytic activity. The results showed that the interesterified selected triacylglycerol molecules were enriched with the hypocholesterolemic fatty acid C18:l, originally located onsn-1,3 positions, on theirsn-2 positions; this fatty acid was favorably interchanged with the hypercholesterolemic fatty acid C16:0, originally located onsn-2 position. The results also indicated that the use of 6 mM of surfactant mixtures increased the acyl exchange reaction toward the long-chain saturated fatty acid C16:0 on the sn-2 position of triacylglycerol molecules.