Jurnal Teknologi dan Industri Pangan (Dec 2006)
ISOLASI DAN KARAKTERISASI MELANOIDIN KECAP MANIS DAN PERANANNYA SEBAGAI ANTIOKSIDAN [Isolation and characterization of soy sauce melanoidin and its role as antioxidant]
Abstract
Controlling oxidation in natural and processed foods is a difficult aspect of food preservation, even in low-fat foods. Lipid oxidation not only produces characteristic undesirable odors and flavor, but also decreases the nutritional quality and safety of foods by formation of secondary reaction products during cooking and processing. Protection of foods against lipid oxidation usually involves exclusion of oxygen by packing in vacuum or inert gases and/or the addition of antioxidants. The Maillard reaction is complex reaction. A variety of by products, intermediates and brown pigmens (melanoidins) are produced, which may contribute to the flavor, antioxidative activity and color of food. The oxidative browning of soy sauce is considered to have a different mechanism from those of ascorbic acid, polyphenols and furfural, because the amount of these compounds in soy sauce is very small. Maillard reaction products of soy sauce were fractionated into high and low molecular weight compounds by ultrafiltration. Oxidative stability was evaluated in refined soybean oil containing compounds in soy sauce and butylated hydroxytoluene (BHT). Oils were oxidized at 110 oC and determined by the rancimat method and TBA value. The high molecular compounds (MW ≥100 kDa) of soy sauce was found to be more inhibitory on the oxidation of soybean oil with protective index 2.43. Characteristic UV-Vis absorption was 360 – 406 nm and IR spectra indicated –OH...O groups of β-diketon or combinated C=R=R groups.
