Effect of different ultrasound conditions and other parameters on solids gain, water loss, and properties of osmotically dehydrated carrots

Abstract

Osmotic dehydration (OD) of carrots was studied by varying the OD conditions (ultrasound as pretreatment [USP], ultrasound‐assisted OD [USOD], and OD without ultrasound [no treatment]), solute concentration (50, 60, and 70°Brix) and solid‐to‐solution ratio (1:3, 1:4, and 1:5). The osmotically dehydrated carrots obtained from the different combinations were then analyzed for solid‐gain (SG) and water loss. Color and texture measurements along with carotenoid content were also studied. Among the different solid‐to‐solution ratios (1:3, 1:4, and 1:5), samples dehydrated with 1:4 yielded the best result for different tests. USOD samples (1:4) gave significantly (p < 0.05) better results for water‐loss (68.74%) and SG (16.57%) as compared to SG of USP (12.46%) and SG of non‐treated samples (11.6%). USOD samples underwent the least amount of color change but had significantly higher values of hardness (240.38 N) than other treatments. The yield of total carotenoids was also significantly (p < 0.05) higher in the USOD samples (22.30 mg/100 g) when compared with USP (18.27 mg/100 g) and non‐treated samples (13.94 mg/100 g). The better quality of products from USOD treatment in terms of color, texture, and nutrition can make it a popular choice in the food industry for various applications.Practical applicationsOsmotic dehydration (OD) is a useful technique to preserve the nutritional and sensory qualities of carrots and extend its shelf life. OD is a time‐consuming process and the rate of mass transfer from foods can be increased when OD is combined with other processes. Ultrasound (US) processing is a non‐thermal process that can be used to increase the mass transfer rate during the OD process. In the present work, US was applied as a pretreatment before carrying out the OD process and during the OD process, that is, US was applied in the osmotic solution after putting the carrot slices to see which method was better in increasing the mass transfer rate and preserving the quality of the dehydrated carrots. The findings will help in deciding the proper way for US to be applied for the OD process for carrots and can be extended to other fruits and vegetables.