Drying of lotus rhizome slices: Influence of drying conditions on Fourier transform infrared spectroscopy, rheology, functional, and physicochemical characteristics of lotus rhizome powder

Abstract

AbstractFresh lotus rhizome has a limited harvesting duration and is prone to browning leading to fast decomposition. Lotus rhizome powder (LRP) can be an innovative substitute to unravel this difficulty, valorize the product and improve its export potential. Microwave blanched lotus rhizome (LR) slices revealed the logarithmic model as the best drying model of fresh LR slices. Water activity (Aw) portrayed strong dependence on drying time; color parameters, a* increased, while L* and b* decreased with slice thickness. Water and oil absorption capacity (WAC and OAC) of lotus rhizome powder (LRP) changed from 4.95 to 1.68 g/g and 2.99 to 0.52 g/g, respectively, with a sharp increase in OAC of samples dried at 80°C. Storage modulus (G′) was higher than loss modulus (G″). Samples of 3 mm thickness dried at 50, 60 and, 70°C had the lowest flow behavior index (n) of 0.2219. Fourier transform infrared spectra of LRP displayed regions of polyphenols with slight deviations for different drying temperatures. It was concluded that 3 mm thick slices dried at 60–80°C required lesser time and possessed better WAC, OAC, and color values.Practical ApplicationsRecently, vegetable powders have driven the attention of food process engineers due to their stability and wide nutritional gamut. Thus, it is attempted to develop and characterize the Lotus (Nelumbo nucifera Gaertn) rhizome powder which will not only make it readily available but will find its practical utilization as an ingredient in food formulations. Lotus rhizome powder is a unique blend of nutrients and bioactive components; therefore, it is important to understand its properties, drying behavior, and engineer the powder development with maximum functionality. Primarily, the lotus rhizome being a perishable vegetable, can be improved for shelf‐life stability and safety. Secondarily, the lotus rhizome powder can be incorporated as the functional ingredient, in flavoring, food, and pharmaceutical industry. Therefore, it is of prime significance to add value to this aquatic vegetable to make it an ideal food resource in the future.