Abstract

The effects of long term organic nutrient management (after 10 years of organic farming) on rice quality, especially with reference to the antioxidant properties of an aromatic indica rice cultivar Geetanjali were investigated during wet and dry season of 2012–13. Seven different combinations of organic manures were applied as a nutrient source. The estimation of total phenolic content, DPPH antioxidant activity and total flavonoids were carried out by spectrophotometer and γ-oryzanol content (GO) by HPLC. All other physicochemical parameters were measured by standard laboratory methods. It was observed that total antioxidant capacity (88.38% inhibition of DPPH), γ-oryzanol (417.4 μg/g) and total phenolic content (277.67 μg/g) were higher in farm yard manure (FYM) + green manure (GM with Sesbania aculeate) treatment, whereas flavonoids, soluble protein and crude oil content were highest under only GM treated field. The physico-chemical and cooking properties of grain did not vary significantly among the treatments except amylose content (AC) and gel consistency (GC). The nutritional quality in terms of antioxidant compounds, protein and crude oil content was depleted after cooking of the grains. Therefore, application of FYM+GM (with Sesbania aculeate; 1: 1 N basis) or at least GM application instead of any other combinations of organic manure at the time of land preparation may be useful for improving nutritional quality of rice under long term organic nutrient management.