engleski

Utilization of vacuum drying in retention of β- carotene content in winter squash (Cucurbita moschata)

Among unit operations, conventional convection drying process is one of the most energyintensive, stimulating degradation of heat- sensitive food nutrients. To overcome such constraints, vacuum drying can be a potential alternative. The low pressure applied in vacuum drying allows water evaporation at lower temperatures allowing preservation of heat- sensitive bioactive compounds. The aim of this study was to determine the effects of vacuum drying on β-carotene content in winter squash. Fresh winter squash fruits (cv. ’Piena di Napoli’) were prepared for drying, peel and seeds were removed while pulp was cut into thick slices (3 mm). The conduction drying was performed at atmospheric pressure (1013.25 mbar) at 70 °C, while for vacuum drying, pressures (50 and 150 mbar) and temperatures (60 and 70 °C) were varied. Winter squash slices were dried to a final water content of 14%. The β-carotene content in all samples was determined spectrophotometrically at 450 nm. Drying by conduction had the most adverse effect on β-carotene content (70.53 mg/100 g DW). The highest β-carotene content (153.69 mg/100 g DW) was determined in sample dried by vacuum at 50 mbar and 60 °C. Regardless of temperature, β-carotene content was lower in samples dried at 150 mbar compared to 50 mbar. Additionally, regardless of applied pressure, lower β-carotene content was determined at higher temperatures. Based on the obtained results, it can be concluded how proper combination of pressure and temperature provide an effective way for the retention of β-carotene content in plants processed by vacuum drying. Also, it should be emphasized that vacuum drying is an effective drying process in preservation of unstable food nutrients, such as carotenoids.

Carotenoids ; Drying ; Retention ; Vacuum

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