Process Modeling and Convective Drying Optimization of Raspberry Pomace as a Fiber-Rich Functional Ingredient: Effect on Techno-Functional and Bioactive Properties
This study aimed to transform raspberry pomace, a by-product of the berry industry, into a sustainable, fiber-rich functional ingredient using convective drying. Drying experiments were conducted at temperatures of 50, 60, 70, 80, and 90 °C to identify the optimal conditions that balance process eff...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-11-01
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| Series: | Foods |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2304-8158/13/22/3597 |
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| Summary: | This study aimed to transform raspberry pomace, a by-product of the berry industry, into a sustainable, fiber-rich functional ingredient using convective drying. Drying experiments were conducted at temperatures of 50, 60, 70, 80, and 90 °C to identify the optimal conditions that balance process efficiency and preservation of functional and bioactive properties. The best results were achieved at 70 °C, where a high drying rate (<i>DR</i>) of 0.46 kg H<sub>2</sub>O·kg<sup>−1</sup> db·min<sup>−1</sup>, effective moisture diffusivity (<i>D</i><sub>eff</sub>) of 1.53 × 10<sup>−10</sup> m<sup>2</sup>·s<sup>−1</sup>, and activation energy (<i>E</i><sub>a</sub>) of 34.90 kJ·mol<sup>−1</sup> were observed. The Page model accurately represented the drying behavior (<i>R</i><sup>2</sup> = 0.9965−0.9997). Total dietary fiber (TDF) content remained stable across temperatures (52.52–64.76 g·100 g<sup>−1</sup> db), while soluble dietary fiber (SDF) increased by 43.40%, resulting in a solubility (SOL) of 71.8%, water-holding capacity (WHC) of 8.2 mL·g<sup>−1</sup> db, and oil-holding capacity (OHC) of 3.0 mL·g<sup>−1</sup> db. High retention of bioactive compounds was achieved at 70 °C, including phenolics (32.10 mg GAE·g<sup>−1</sup> db) and anthocyanins (25.84 mg C3G·g<sup>−1</sup> db), resulting in significant antioxidant activities (DPPH: 33.29 mg AAE·g<sup>−1</sup> db, IC<sub>50</sub> 0.016 mg·mL<sup>−1</sup>; ABTS: 35.85 mg AAE·g<sup>−1</sup> db, IC<sub>50</sub> 0.029 mg·mL<sup>−1</sup>). These findings demonstrated the potential of convective drying at 70 °C to efficiently transform raspberry pomace into a high-quality functional ingredient. This process promotes sustainable production and waste reduction in the berry industry. |
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| ISSN: | 2304-8158 |