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Anaerobically treated molasses-based distilleries spent wash is a major source of terrestrial and aquatic pollution due to the mixture of the various unknown organometallic compounds in discharged waste. The nature of pollutants present in effluent has to be characterized prior to the evaluation of their fate in the environment at various tropic levels. The absorption maxima (λmax) were obtained at 295 nm of pollutants present in spent wash which indicated that melanoidins are a major colorant along with other organic compounds. Abundantly identified compounds with GC–MS in effluent were found: 1,2,4,5-tetrahydro-2-methyl-3H-2-benzazepine-3-one, 6-(trifluoromethyl)-1H-imidazole [4,5-c] pyridine, 4,6-di-t-butyl-1H, 3H-thieno[3,4-c] thiophene, butanoic acid, trimethylsilyl ester, silane, (dodecyloxy)trimethylsilyl ester, 4-styryl [2,2] paracyclophane, 4-(p-cumylphenoxy) phthalonitrile, hexadecanoic acid, trimethylsilyl ester, butyl ester, and squalene. Some of these compounds are known with mutagenic and androgenic properties. The toxicity test of post-methanated distillery effluent (PMDE) showed direct toxic effects on catfish (Heteropneustes fossilis) even at 1% (v/v) concentration and caused degeneration of primary and secondary lamellae of the gill and the epithelial layer. Further, higher concentrations between 5 and 10% of PMDE showed loss of primary and secondary lamellae of gills, and liver catalase activity was also increased dramatically in H. fossilis, indicating the generation of oxidative free radicals. Similarly, inhibition of α-amylase activities in germinating Zea mays L. (Maize) seeds was also noted at 10% PMDE. This study confirmed the environmental toxicity of effluent with freshwater fish and Zea mays seeds.

Melanoidins are the randomly polymerized condensed anionic, non-enzymatic product of maillard reaction between amino and carbonyl group at elevated temperature. It occurs particularly during the food processing and wastewater released from distilleries and various fermented industries. Their synthesis is influenced by several factors because they alter the reaction path and change the product composition. Moreover, melanoidins have been known to be beneficial at low concentrations in food products due to their several properties in a biological system. But, when they are released into the environment at a high concentration from fermentation industries they cause a serious threat to land and aquatic ecosystem. This review encompasses the detailed chemical reaction of melanoidin synthesis and its functional properties to various substances present in nature with implications to its impact on the environment and their role in maintaining the nutritional and flavoring properties in food products.