LAUSR

BACKGROUND Choosing an effective alternative-green-pretreatment to chemical-pretreatments is required for the effective hot air drying of foods e.g. jujube. Jujube slices were pretreated using ultrasound-assisted vitamin C (5 and 10 mg/mL, UVC) for 10, 20, and 30 min followed by hot air drying. RESULTS UVC pretreatment for 10, 20, 30 min modulated the characteristics of fresh jujube slices such as water loss (from -28.25% to -25.52% after 30 min of UVC pretreatment), solid gain (from -31.68% to -26.82% after 30 min of UVC pretreatment), total and reducing sugars loss (from 200.25 mg and 34.88 mg to 287.14 mg and 4.71 mg, respectively, after 30 min of UVC pretreatment), total soluble solid (from 76.32 o Brix to 82.08 o Brix), and water diffusivity (from 9.01×10-10 m2 /s to 6.71×10-10 m2 /s), which were associated with altered surface morphology and improved drying characteristics. The UVC pretreatment preserved an acceptable reddish-yellow or orange-like color during hot air drying and reduced the browning index (from 26.3 OD/g DM to 23.25 OD/g DM) that was connected with reduced 5-hydroxymethylfurfural (HMF) content. On the contrary, bioactive components such as vitamin C (from 1.05 mg/g DM to 9.02 mg/g DM), phenolics (from 12.8 mg GAE/g DM to 17.5 mg GAE/g DM), flavonoids (from 4.0 mg RE/g DM to 4.4 mg RE/g DM), and procyanidins content (from 2.0 mg CE/g DM to 2.9 mg CE/g DM) were comparatively increased in UVC pretreated jujube slices, which had positive association with the increased antioxidants activity e.g. ABTS (from IC50 22.5 mg DM/mL to 8.0 mg DM/mL), DPPH (from IC50 36.5 mg DM/mL to 9.5 mg DM/mL), and FRAP (from 2.0 mg VCE/g DM to 11.9 mg VCE/g DM). CONCLUSION According to obtained data, ultrasound-assisted vitamin C can be used as a promising pretreatment method for improving hot air drying characteristics and quality attributes of jujube slices. This article is protected by copyright. All rights reserved.