Encapsulation of extract from roasted Kabkab date (Phoenix dactylifera L.) seed using freeze-drying

Document Type : Research Article


1 Ph.D. student, Department of Food Science and Technology, Sarvestan Branch, Islamic Azad University, Sarvestan, Fars, Iran

2 Assistant Professor, Department of Food Science and Technology, Sarvestan Branch, Islamic Azad University, Sarvestan, Fars, Iran.

3 Assistant Professor, Department of Fisheries, Faculty of Marine Natural Resources, Khorramshahr University of Marine Science and Technology, Khorramshahr, Iran


The present study aimed to investigate the physicochemical characteristics of the encapsulated roasted date-seed (180°C, 20 min) extract. Date-seed (Phoenix dactylifera L. cv Kabkab) extract was obtained using a combination of ultrasound- (25 ± 5 ºC, 15min.) and microwave- (2.30min.) assisted extraction. Phenolic-compounds of the extract were identified by HPLC. The encapsulation process was done by the freeze-drying method. Soy-protein concentrate and maltodextrin were used as wall materials (M(100): Pure Maltodextrin; S(100): Pure Soy-protein; MS(75:25): Maltodextrin: Soy-protein (75:25%); MS (50:50): Maltodextrin: Soy-protein (50:50%); MS (25:75): Maltodextrin: Soy-protein (25:75%)). Gallic-acid (536.87 mg 100 g-1dEx) and catechin (214.79 mg 100 g-1dEx) were the major phenolic and flavonoid compounds of the extract. The type of wall material had no significant effect on the moisture content and water-activity. The microparticle's bulk-density was varied from 0.232-0.178 g cm-3. The difference between M(100) and S(100) was significant. The microparticles showed a heterogeneous and irregular structure with flake- and sheet-shaped morphology. Several cracks were visible on the M(100) surface. The best encapsulation-efficiency was achieved for microparticles using a combination of maltodextrin and soy-protein (especially, MS(50.50)). While 68.88% of free-extract polyphenols were destroyed after 35 days at 35 °C, the encapsulation process caused retaining 61.79% (M(100)) to 76.69% (MS(50.50)). Overall, due to the appropriate solubility, low moisture, water-activity and the ability to preserve phenolic compounds of date-seed extract, encapsulation in maltodextrin-soy-protein (MS(50.50)) wall materials could be proposed as an efficient and cost-effective bioactive compound to preserve different food products and improve their nutritional value.

Graphical Abstract

Encapsulation of extract from roasted Kabkab date (Phoenix dactylifera L.) seed using freeze-drying


  • The phenolics of date-seed extracted by ultrasound-microwave-assisted method was identified.
  • Date-seed extract was encapsulated by maltodextrin (MD) and soy protein concentrate (SPC).
  • Encapsulation efficiency of MD-SPC samples was better than others.
  • Microparticles of date seed extract are an effective and affordable bioactive compound.


Main Subjects

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