Key points are not available for this paper at this time.
• Steaming significantly increased electrical conductivity in carrot tissues. • Cooking reduced glucose, fructose, and sucrose levels in carrots. • Freezing preserved amylase activity and enhanced proline accumulation. • Cooking failed to eliminate heavy metals from contaminated carrot tissues. • Thermal processing increased oxidative stress markers in carrots This study evaluated how various processing and storage methods affect the nutritional and phytochemical properties of carrots (Daucus carota L.). Carrot samples—fresh, refrigerated, frozen, boiled, steamed, and combinations thereof—were analyzed for sugar levels, enzyme activity, oxidative stress markers, proline content, and heavy metal concentrations. Processing markedly impacted sugar composition: steamed carrots had the highest glucose (43.31 mg·mL⁻¹) and fructose (27.22 mg·mL⁻¹) levels, while boiled/frozen samples had the lowest. Sucrose peaked in frozen-steamed samples (80.43 mg·mL⁻¹). Thermal treatments significantly reduced enzyme activities, with fresh samples showing the highest levels of amylase, peroxidase, and polyphenol oxidase, and boiled samples the lowest. Proline was most abundant in raw frozen carrots (21.03 mg·mL⁻¹) and least in boiled ones (7.35 mg·mL⁻¹). Oxidative stress indicators such as hydrogen peroxide and malondialdehyde (MDA) increased following heat exposure; MDA rose from 0.011 mg·mL⁻¹ in fresh samples to 0.219 mg·mL⁻¹ in boiled/frozen ones. Electrical conductivity ranged from 525 μS/cm in frozen raw carrots to 3,925 μS/cm in steamed samples. Heavy metals like lead, mercury, and cadmium persisted across all treatments, with only partial reductions from boiling or steaming. These results emphasize the need for pollution control during cultivation, as post-harvest processing offers limited detoxification.
Fartoosi et al. (Sat,) studied this question.