Turmeric (Curcuma longa Linn.) is widely recognized for its medicinal properties; however, the potential of Nepalese turmeric varieties, specifically Kapurkot Haledo 1 (KK1), Kapurkot Haledo-2 (KK2), and Sugandha, remains underexplored, particularly in relation to their processing outcomes and quality characteristics. This study aimed to evaluate the effects of different blanching methods on these varieties' quality traits. Using a Completely Randomized Design (CRD), the experiment tested three blanching treatments: distilled water boiling (DWB), alkaline water boiling (AWB), and a control, with nine treatment combinations, each replicated four times. Statistical analysis showed that KK2 had the highest dry recovery percentage (23.51%), with DWB proving more effective than AWB. KK1 exhibited the most significant length shrinkage, whereas KK2 treated with AWB showed the least. In terms of diameter, KK1 and Sugandha showed the highest shrinkage, while KK2 treated with AWB demonstrated minimal shrinkage. For color quality, KK1 received the highest color score (6.75), followed by Sugandha and KK2, with AWB generally enhancing color ratings across the varieties. Significant interactions between turmeric variety and blanching method were observed. Specifically, KK1 with DWB achieved the highest dry recovery, similar to KK2 under AWB treatment. Additionally, Sugandha treated with AWB showed the least length shrinkage, and KK2 exhibited the lowest diameter shrinkage under both control and AWB treatments. Regarding oil content, KK1 and Sugandha retained the highest levels under control conditions, while KK2 with AWB showed the lowest ash content and the highest curcumin concentration in the control group. In summary, the findings suggest that the combination of KK2 with AWB or DWB yields optimal outcomes across multiple quality parameters, underscoring the effectiveness of these blanching methods as post-harvest processing techniques for enhancing the quality of Nepalese turmeric.

The objective of this study was to investigate the effect of pre-treatment and drying temperature on the drying kinetics and nutritional quality of tomato (Lycopersicon esculantum L.) under hot air drying. Tomato samples were blanched at 80oC and osmotically dehydrated using 20% w/w sodium chloride solutions at 30oC for 20 min. The blanch-osmotic pre-treated and untreated tomato slices were dried at temperature of 40, 50, 60, 70 and 80oC, respectively in a hot air-dryer. The results showed that blanch-osmotic pre-treatment offered a higher drying rate and lower or faster drying time than untreated condition. The tomato drying regime was characteristically in the constant and falling rate period. The tomato drying rate curve showed characteristics of porous hygroscopic solids. The optimum drying temperature for tomato was found to be 60oC. Four semi-empirical drying models of Newton, Page, Henderson and Pabis, and Logarithmic were fitted to the drying data using non-linear regression analysis. The most appropriate model was selected using the coefficient of determination (R2) and root mean square error (RMSE). The Page model has shown a better fit to the drying kinetics data of tomato in comparison with other tested models. Transport of moisture during drying was described by Fick’s diffusion model application and the effective moisture diffusivity (Deff) thus estimated. The Deff at 60oC was 4.43 × 10-11m2/s and 6.33 × 10-11m2/s for blanch-osmotic pre-treated and untreated tomato slices, respectively.

The objective of this study was to investigate the effect of pre-treatment and drying temperature on the drying kinetics and nutritional quality of tomato (Lycopersicon esculantum L.) under hot air drying. Tomato samples were blanched at 80oC and osmotically dehydrated using 20% w/w sodium chloride solutions at 30oC for 20 min. The blanch-osmotic pre-treated and untreated tomato slices were dried at temperature of 40, 50, 60, 70 and 80oC, respectively in a hot air-dryer. The results showed that blanch-osmotic pre-treatment offered a higher drying rate and lower or faster drying time than untreated condition. The tomato drying regime was characteristically in the constant and falling rate period. The tomato drying rate curve showed characteristics of porous hygroscopic solids. The optimum drying temperature for tomato was found to be 60oC. Four semi-empirical drying models of Newton, Page, Henderson and Pabis, and Logarithmic were fitted to the drying data using non-linear regression analysis. The most appropriate model was selected using the coefficient of determination (R2) and root mean square error (RMSE). The Page model has shown a better fit to the drying kinetics data of tomato in comparison with other tested models. Transport of moisture during drying was described by Fick’s diffusion model application and the effective moisture diffusivity (Deff) thus estimated. The Deff at 60oC was 4.43 × 10-11m2/s and 6.33 × 10-11m2/s for blanch-osmotic pre-treated and untreated tomato slices, respectively.