Ajay Kumar Gupta, Mohan Singh, Suhagni Patel, Mansvi Gour, Somya Nandanwar and Ritika Saini

Water chestnut (Trapa natans) also known as Singhara or pani phal is a neglected but economically important natural crop. It is an aquatic crop grown in different states of India. It is commonly grown in water stagnant areas. In India, it is traditionally consumed in raw with only washing with fresh water or after boiling. Most commonly used water chestnut product is the flour generally used during festive season in India. Physical properties of water chestnut are helpful for designing of the post-harvest processing machineries. The mean values of length, width and thickness for whole water chestnuts are useful in the designing of a grading machine. Bulk density and true densities are helpful in the design of the washer. To remove the inedible cover attached with the dried whole water chest kernels, manual and power operated water chestnut decorticator were designed. For manual water chestnut decorticator optimum screen was reported 38.07% perforation area on the basis of shelling coefficient, decortication efficiency and specific energy requirement. The shelling efficiency obtained for Rhombus Slotted Mesh screen was reported the maximum. Effects of moisture content and screen perforation area on decortication efficiency of water chestnut decorticator were also investigated. A combined water chestnut peeling machine which used a rotary knife to remove bud and root, and a differential friction belts to remove side peel was also designed and the working loss of the combined water chestnut peeling machine 43.03% and the comprehensive peeling rate 77.43% were reported. Drying characteristics of water chestnut were evaluated in a commercially available cabinet oven at different air temperatures (50, 60, 70, 80 and 90°C) to compare the drying rate and to analyse the effect of different drying air temperature on rehydration properties. The product dried at 70° C had better rehydration characteristics when compared to others. Various pretreatments given to water chestnut slices with 0.1 g/100 g (potassium metabisulphite) and 0.5 g/100 g citric acid for 30 min before drying exhibited best results in terms colour of the flour. A ready-to-brew beverage powder was developed from water chestnuts flour by freeze-drying. Two times concentration of water chestnuts flour water and added with 20% maltodextrin showed the result in the highest sensory acceptance score.

DOI: 10.22271/phyto.2025.v14.i2a.15273

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