Compression loading behaviour of sunflower seeds and kernels

The present study was carried out to investigate the compression loading behaviour of five Indian sunflower varieties (NIRMAL-196, NIRMAL-303, CO-2, KBSH-41, and PSH-996) under four different moisture levels (6-18% d.b). The initial cracking force, mean rupture force, and rupture energy were measured as a function of moisture content. The observed results showed that the initial cracking force decreased linearly with an increase in moisture content for all varieties. The mean rupture force also decreased linearly with an increase in moisture content. However, the rupture energy was found to be increasing linearly for seed and kernel with moisture content. NIRMAL-196 and PSH-996 had maximum and minimum values of all the attributes studied for both seed and kernel, respectively. The values of all the studied attributes were higher for seed than kernel of all the varieties at all moisture levels. There was a significant effect of moisture and variety on compression loading behaviour

Compression loading behaviour of sunflower seeds and kernels

The present study was carried out to investigate the compression loading behaviour of five Indian sunflower varieties (NIRMAL-196, NIRMAL-303, CO-2, KBSH-41, and PSH-996) under four different moisture levels (6-18% d.b). The initial cracking force, mean rupture force, and rupture energy were measured as a function of moisture content. The observed results showed that the initial cracking force decreased linearly with an increase in moisture content for all varieties. The mean rupture force also decreased linearly with an increase in moisture content. However, the rupture energy was found to be increasing linearly for seed and kernel with moisture content. NIRMAL-196 and PSH-996 had maximum and minimum values of all the attributes studied for both seed and kernel, respectively. The values of all the studied attributes were higher for seed than kernel of all the varieties at all moisture levels. There was a significant effect of moisture and variety on compression loading behaviour

Experimental investigation of shrinkage and microstructural properties of date fruits at three solar drying methods

The effect of solar drying methods on shrinkage and the corresponding influence on microstructural changes of dates at three ripening stages (khalal, rutab and tamr) were investigated and evaluated shrinkage models that are best describing the shrinkage behavior. Drying was accomplished by forced convective solar dryer, greenhouse tunnel dryer and open sun drying. It was observed that, the greenhouse tunnel dryer had 37, 38 and 38% lower drying time for khalal, rutab and tamr stage dates, respectively compared to open sun drying, whereas the drying time was lower by 15, 29 and 30%, respectively in forced convective solar dryer. The drying methods and ripening stages had significant effect on shrinkage attributes of dates. Dates dried in the forced convective solar dryer had the lowest percentage of shrinkage in length (7–9%), diameter (10–27%) and volume (25–51%) at the three ripening stages followed by greenhouse tunnel dryer (7–13%, 12–27% and 29–53%, respectively) and open sun drying (8–13%, 17–32% and 37–60%, respectively). The quadratic equation was proposed as the best model to describe the volumetric shrinkage of dates as a function of moisture content or moisture ratio at the three ripening stages for all the three drying methods. Microstructural analysis of date tissue revealed that forced convective solar dryer had the least structural deformation at the three ripening stages. Overall, forced convective solar dryer produced the best quality of dried dates

Effect of solar drying methods on color kinetics and texture of dates

The present work investigates the effect of solar drying methods on the color and textural attributes of Khalas dates at three ripening stages (khalal, rutab and tamr) and evaluates color change kinetics using three kinetic models. Three solar drying methods, namely, open sun drying (OSD), forced convective drying (FCD) and greenhouse tunnel drying (GTD) were studied. The drying methods and ripening stages had significant effect on all color attributes. Khalal stage dates dried in FCD had the lowest color variations (L*: −12%, a*: +4%, b*: −46%, chroma: −38%, hue angle: −21% and total color change, ΔE:14.05) and thus, the highest color stability. At the end of drying, color of rutab and tamr stage dates changed red-brown in all the three drying methods due to the massive loss of b* (88–92%) and hue angle (63–73%), and altering hue angle from 23° (tamr fresh) to 9–12° (dried), respectively. The most appropriate model to describe the color change kinetics of dates at the three ripening stages was the fractional conversion model. The texture profile analysis revealed that FCD produced the softest dates for all the three ripening stages (hardness ranged 2.52–3.42 N). Overall, dates dried in FCD had the best color and textural properties as compared to the OSD and GTD dried dates in all ripening stages