An apparatus and method for managing a residual content in a food product during a milling process comprises a detecting member (100), a computation member (200) and a diverting member (300). The detecting member (100) implemented with a light emitting member is configured to permit irradiation on the food product by a predetermined wavelength of light energy in a near-infrared (NIR) spectrum. The detecting member (100) is configured to measure values of at least one of residual content and constituent concentrations after the irradiation. The computation member (200) configured to indicate a grade quality of the food product by computing a compared value by comparing a predetermined value with the measured value. The diverting member (300) configured to divert the food product to respective chambers based on the computed compared value of the at least one of the residual content and constituent concentration.
