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Natural Food Resource Valorization by Microwave Technology: Purslane Stabilization by Dielectric Heating
Marco Apicella1, Giuseppe Amato1, Pietro de Bartolomeis2
1Department of Pharmacy, University of Salerno, Via Giovanni Paolo II 132, 84084 Fisciano, Italy.
Foods (Basel, Switzerland)
|January 17, 2024
Summary
Microwave drying preserves more beneficial fatty acids and phytosterols in purslane (Portulaca oleracea L.) compared to conventional methods. This sustainable technique enhances the nutritional profile of purslane, transforming it into a valuable food source.
Area of Science:
- Food Science and Technology
- Sustainable Agriculture
- Nutritional Chemistry
Background:
- Microwave-assisted drying offers sustainable processing for food stabilization, particularly in the agro-food industry.
- Purslane (Portulaca oleracea L.) is a nutrient-rich plant with antioxidant and pharmacological properties, showing potential as a future food ingredient.
- Understanding heat and mass transfer during drying is crucial for preserving the nutritional quality of plant-based foods.
Purpose of the Study:
- To evaluate the impact of different drying methods (convective, microwave irradiation, microwave-vacuum irradiation) on the nutritional profile of purslane.
- To investigate the role of drying rates and heat/mass transfer phenomena on the preservation of key compounds in purslane.
- To explore the potential of transforming purslane from a weed into a valorized food source through optimized drying techniques.
Main Methods:
- Application of convective, microwave irradiation, and microwave-vacuum irradiation drying protocols to different parts of purslane (apical, twigs, entire structures).
- Chemical characterization of dried purslane samples using Gas Chromatography-Mass Spectrometry (GC/MS) analysis of extracts.
- Comparative analysis of drying times and preservation rates of fatty acids and phytosterols across different methods.
Main Results:
- Microwave treatments significantly improved the preservation of fatty acids (SFAs, MUFAs, PUFAs) and phytosterols in purslane compared to convective drying.
- Fatty acids constituted over 90% of total components in apical parts and 85% in microwave-vacuum-dried entire purslane samples.
- Drying rates in microwave treatments were up to three orders of magnitude faster than convective methods, influencing chemical composition and preservation.
Conclusions:
- Microwave-assisted drying is a superior technique for preserving the nutritional quality of purslane, particularly its valuable fatty acid and phytosterol content.
- The rapid drying rates achieved with microwave technology contribute to enhanced preservation and reduced processing times.
- Optimized microwave drying protocols can effectively valorize purslane, supporting its development as a functional food ingredient.
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