A sustainable infrared dry peeling method for shallots (Allium cepa L. aggregatum): comparison of nutritional, enzymatic and sensory characteristics of infrared and conventional peeling methods

Abstract

Traditional peeling methods involve the usage of a high amount of water which leads to effluent generation, high biological oxygen demand and salinity and need for waste water treatment plants. However, infrared peeling can be an alternative to overcome the problems as it does not involve water. Thus, phytochemical, antioxidant, functional and sensory parameters were compared between infrared and conventional peeling methods (steam, lye, hot-water, flame and untreated hand peeling). Phytochemical analysis revealed that infrared peeled shallots exhibited similar quality attributes to hand peeled shallots. Peroxidase activity was higher in hand-peeled and the lowest in flame peeled shallots, and the activity in infrared peeled shallots was similar to that in other traditional treatments. During Fourier transform infrared analysis, it was observed that both infrared-peeled and hand peeled samples shared similar functional group compositions that are responsible for the aromatic nature of the shallots. X-Ray diffraction analysis showed the typical agricultural characteristics (amorphous and crystalline) that are inherent in shallots. The acceptance was higher for hand peeled and infrared peeled shallots determined by sensory evaluation and analysed by the fuzzy logic method. This research highlights the potential of infrared dry peeling as a sustainable alternative, offering promising outcomes in quality preservation.