Kinetics and Mechanism of Oxidation of Vanillin by Chromium(VI) in Sulfuric Acid Medium

Vanillin is a phenolic aldehyde, which is an organic compound including aldehyde, hydroxyl and ether. It is the primary component of the extract of the vanilla bean. Vanillin is a significant flavoring reagent in the industry of food and is widely used in the production of drugs. It has been also used as a chemical intermediate in the preparation of pharmaceuticals and other fine chemicals. Furthermore, it is used in the synthesis of perfume and as a catalyst in various polymerization reactions. When the hydroxyl group in vanillin molecule is protected, vanillin is oxidized to vanillic acid. Kinetics of oxidation of vanillin has been studied previously in alkaline solutions by different reagents, as hexacyanoferrate(III), diperiodatoargentate(III), bismuth(V), diperiodatonickelate(IV) and periodate catalyzed by ruthenium(III), and in acid media by cerium(IV).

Oxidation reactions are very important in nature and in organic synthesis. Among the most important oxidants is chromium(VI) which may play a significant role in the chemistry of vanillin in the environment due to the mutagenic and carcinogenic activity of chromium. Chromium exists in both trivalent, Cr(III), and hexavalent, Cr(VI), species in aqueous solutions and the two oxidation states are identified by various physical/chemical behavior and toxicity. 

Chromium(VI) compounds are very dangerous for biological systems, but those of chromium(III) are relatively non-toxic. Chromium(VI) is employed for oxidation of organic compounds and it is reduced to lower oxidation states [9]. The chemistry of Cr(V) and Cr(IV) as intermediate species which may be formed during reduction of chromium(VI) were attracted many researchers because of their involvement in the mechanism of Cr–induced cancers

Stimulatory Effect of Hormones, Vitamin C on Growth, Yield and Some Metabolic Activities of Chenopodium quinoa Plants in Egypt

Increasing yield for an ever growing world population has currently become a topic of great concern with regard to food security. Especially in Africa, agricultural productivity has not been able to cope with population growth, leading to increased annual imports and food insecurity.

The year 2013 was declared The International Year of the Quinoa (IYQ2013) by the Food and Agriculture Organization of the United Nations (FAO) in recognition of the indigenous peoples of the Andes who have maintained, controlled, protected and preserved quinoa as human food for present and future generations using their traditional knowledge and practices of living in harmony with the earth and nature. Because it is already part of existing high-value agro biodiversity, quinoa is poised to play an important role in strategies designed to adequately feed the growing world population in a sustainable manner .

In comparison to most cereals, quinoa seeds have a higher nutritional value.Quinoa is a good source of essential amino acids such as lysine and methionine. Quinoa contains relatively high quantities of vitamins (thiamine, vitamin C) and minerals.

Quinoa is a highly nutritious food crop, with an outstanding protein quality and a high content of a range of vitamins and essential minerals. Quinoa has enormous potential in the food industry being gluten-free and highly nutritious. This is of great importance for the nutritional value of cereals, because a high content of dietary fibre has positive effects on the reduction of the cancer risk. In general, quinoa contained higher total mineral contents than the other cereals such as rye and wheat.