Kojic Acid Practical Class 2 PDF

Kojic acid Practical class 2  Historical Background Kojic acid is a chelation agent produced by several species of fungi, especially Aspergillus oryzae, which has the Japanese common name koji. Kojic acid is a by-product in the fermentation process of malting rice, for use in t...

Kojic acid Practical class 2  Historical Background Kojic acid is a chelation agent produced by several species of fungi, especially Aspergillus oryzae, which has the Japanese common name koji. Kojic acid is a by-product in the fermentation process of malting rice, for use in the manufacturing of sake, the Japanese rice wine. Saito (1907) isolated the acid as a byproduct of rice fermentation by Aspergillus oryzae. Yabuta (Japanese biochemist) investigated the acid isolated by Saito and named it Kojic acid in 1912 and established its chemical structure in 1924.  Kojic acid properties Molecular formula of Kojic acid is C6H6O4 and molecular weight is 142.11 g/mol Kojic acid crystallizes in form of colorless, prismatic needles. Melting point of kojic acid ranges between 150- 160°C. Kojic acid is soluble in polar substances like water, ethanol, ethyl acetate etc. On the contrary, kojic acid is very less soluble in chloroform, ether etc.  Kojic acid (5-Hydroxy-2-(hydroxymethyl)-4H-pyran-4-one)  Producers of Kojic acid Fungi: Aspergillus oryzae, A. glaucus, A. flavus, A. awamori, A. candidus, A. clavatus, A. fumigatus, A. giganteus and others… Bacteria:several species of Acetobacter.  Carbon sources used for Kojic acid production Polysaccharides:starch and dextrins. D isaccharides:sucrose and maltose. Hexoses:glucose (best source), fructose, mannose and galactose. Pentoses:xylose and arabinose. The concentration of carbon containing materials used have been varied between 5 and 30%.  Production of Kojic acid by fermentation Fungal strain used:Aspergillus oryzae. Medium used (May et al. 1931): Ingredient g/L G lucose 200 N H4N O3 1.1 25 MgSO4.7H2O 0.5 KCl 0.1 H3PO4 0.063 pH:2-5 Temperature:30-35°C. Incubation period:9-20 days.  Production of Kojic acid by fermentation Medium used (Kinoshita 1927): Ingredient g/l Sucrose 100 N H4N O3 0.4 MgSO4.7H2O 0.5 KCl 0.1 KH2PO4 0.063 pH:2-5. Temperature:30-35°C. Incubation period:9-20 days.  D etection of Kojic acid Kojic acid can be detected by two methods: 1.Crystals of kojic acid can be obtained if culture filtrate stored in refrigerator at 5°C overnight. 2.It forms intense red color with Ferric Chloride.  Production of Kojic acid by fermentation May et al. (1931) found that ethylene chlorohydrin in a concentration of 100 mg/L increase the yield of Kojic acid after 10 days of incubation. Oxalic, citric, hydrochloric and nitric acids inhibit the formation of Kojic acid by fermentation (Barham and Smith 1934). Temperature may be dropped to 25°C or lower after the fermentation has proceeded at a higher temperature for about 5 days results in increased yields.  D uration of fermentation The fermentation requires 9-20 days to complete. The period depend on the type of substrate, mold species, temperature, pH and other factors. After the sugar has been consumed, the kojic acid may be utilized by the mold resulting I decreased yields. Yields 50-60 % produced from glucose solution by A. flavus.  Biosynthesis 13 C-Labelingstudies have revealed at least two pathways to kojic acid. In the usual route, dehydratase enzymes convert glucose to kojic acid. Pentoses are also viable precursors in which case dihydroxyacetone is invoked as an intermediate.  Applications of Kojic acid Kojic acid may be used on cut fruits to prevent oxidative browning. In seafood to preserve pink and red colors In cosmetics to lighten skin. Kojic acid also has antibacterial and antifungal properties. The cocrystals of kojic acid with quercetin were found to have two times better cytotoxic activity to cancer cells in comparison with quercetin itself. Q uercetin is a flavonol found in many fruits, vegetables, leaves, and grains. It can be used as an ingredient in supplements, beverages, or foods. Kojic acid appears to possess marked protective (radioresistance) effects from radiation-induced damage.  Applications of Kojic acid Analytical reagent particularly for iron where it forms a bright red complex with ferric ions. Antibiotic, painkiller, anti-inflammation, anti- diabetic and insecticide. Intermediate for metal chelate production. U sed in food and cosmetics to preserve or change colors of substances. Kojic acid products (skin whitening)