Question

1.Why Ripe olives are treated with solutions of sodium hydroxide (0.25–2.0%), can removal of the bitter principal and to develop a darker color???

2.why NaOH can enhance browing and polymerization of flavoniods in cocoa?

Answer 1

1.Ripe olives are treated with solutions of sodium hydroxide (0.25–2.0%), can removal of the bitter principal and to develop a darker color because the elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids,resulting in a smoother, less acid and less bitter chocolate flavor, a darker color, and a slightly improved solubility. Alkali treatments are imposed on several food products for the purpose of color and flavor improvement.

2.Cocoa contains high levels of different flavonoids The alkalinization treatment resulted in 60% loss of the mean total flavonoid content.

A high temperatureand basic pH conditions favored formation of dark components during alkalization due to sugar degradation, Maillard reactions, and anthocyanin polymerizing. The anthocyanin content decreased with an increasing alkali concentration, suggesting that more anthocyanins were transformed into brown polymers in darker cocoa powder. Cocoa powder with a heavy degree of alkalization had the lowest ratio of monomer anthocyanins to yellow/brown polymer content. OD460/OD525 values for alkalized samples were higher than for non-alkalized samples. Cocoa powder presented a better color quality after alkalization treatment.