Investigation of Physicochemical, Mechanical, Thermal and Rheological Properties of Mrigbahar Nagpur Mandarin (Citrus reticulate Blanco.)

Abstract

Nagpur mandarin (popularly known as Nagpur Santra) is an indigenous fruit with high nutritional and functional value. It is the only cultivar of mandarin grown in Vidarbha region of Maharashtra. As per harvesting time they are ambiabahar (Ocrober-November) and mrigbahar (February-March). Out of these two, mrigbahar is unique to Nagpur and of superior quality, hence taken for the study. The physicochemical, thermal, mechanical, rheological and textural properties of mrigbahar Nagpur mandarin are studied in this work. The sphericity (0.90) of mrigbahar fruit is considered to be spherical. The mean breadth, thickness and length of the fruit are 54.9, 47.3 and 57.9 mm, respectively. The true density, porosity and bulk density are 1.364 g/m³, 65.10% and 0.517 g/m³. The thermal conductivity, thermal diffusivity and specific heat of Nagpur mandarin fruit are 0.588 W/m℃, 11.84 × 10⁻² m²/s and 3.909 kJ/kg℃. Under rheological properties of Nagpur mandarin juice, it is observed that as the shear rate increased, viscosity (ƞ) and shear stress (σ) decreased and Herschel Bulkley model is most suitable to characterise flow behaviour. The textural properties reveal that fracturability with 1% load sensitivity is 10.27 N with respective values of stringiness length (4.04 mm). The findings of this investigation would help for the post-harvest handling, processing equipment and value-added products from Nagpur mandarin.