Physical and Functional Properties of Sweet Potato Flour: Influence of Variety and Drying Method
Sweet potato (<i>Ipomoea batatas</i> (L.) Lam.; SP) flour enhances food nutrition and bioactivity while functioning as a thickening/gelling agent. This study investigated the impact of two drying methods [hot-air (75 °C/20 h) and freeze-drying (−41–30 °C/70 h)] on the physical–functional...
Saved in:
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-04-01
|
| Series: | Molecules |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1420-3049/30/8/1846 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1849713423209725952 |
|---|---|
| author | Nelson Pereira Ana Cristina Ramos Marco Alves Vítor D. Alves Margarida Moldão Marta Abreu |
| author_facet | Nelson Pereira Ana Cristina Ramos Marco Alves Vítor D. Alves Margarida Moldão Marta Abreu |
| author_sort | Nelson Pereira |
| collection | DOAJ |
| description | Sweet potato (<i>Ipomoea batatas</i> (L.) Lam.; SP) flour enhances food nutrition and bioactivity while functioning as a thickening/gelling agent. This study investigated the impact of two drying methods [hot-air (75 °C/20 h) and freeze-drying (−41–30 °C/70 h)] on the physical–functional properties of flours from three SP varieties: <i>Bonita</i> (white-fleshed), <i>Bellevue</i> (orange-fleshed), and <i>NP1648</i> (purple-fleshed). Particle size, morphology, water/oil absorption capacities (WAC/OAC), bulk density, swelling power (SwP), water solubility (WS), foaming/emulsifying properties, least gelation concentration (LGC), and gelatinisation temperature (GT) were analysed. Both the drying method and variety significantly influenced these properties. Hot-air-dried flours exhibited bimodal particle distribution, compact microstructure, and aggregated starch granules, yielding higher WAC (≈3.2 g/g) and SwP (≈3.6 g/g). Freeze-dried flours displayed smaller particles, porous microstructure, and fragmented granules, enhancing OAC (≈3.0 g/g) and foaming capacity (≈17.6%). GT was mainly variety-dependent, increasing as <i>Bellevue</i> (74.3 °C) < <i>NP1648</i> (78.5 °C) < <i>Bonita</i> (82.8 °C), all exceeding commercial potato starch (68.7 °C). <i>NP1648</i> required lower LGC (10% vs. 16% for others). All flours exhibited high WS (24–39.5%) and emulsifying capacity (≈44%). These results underscore the importance of selecting the appropriate drying method and variety to optimise SP flour functionality for targeted food applications. Freeze-dried flours might suit aerated/oil-retentive products, while hot-air-dried flours could be ideal for moisture-sensitive formulations. |
| format | Article |
| id | doaj-art-21614e033daf44a897ac0f98b6cec91b |
| institution | DOAJ |
| issn | 1420-3049 |
| language | English |
| publishDate | 2025-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj-art-21614e033daf44a897ac0f98b6cec91b2025-08-20T03:13:58ZengMDPI AGMolecules1420-30492025-04-01308184610.3390/molecules30081846Physical and Functional Properties of Sweet Potato Flour: Influence of Variety and Drying MethodNelson Pereira0Ana Cristina Ramos1Marco Alves2Vítor D. Alves3Margarida Moldão4Marta Abreu5Unidade de Tecnologia e Inovação, INIAV—Instituto Nacional de Investigação Agrária e Veterinária, 2780-157 Oeiras, PortugalUnidade de Tecnologia e Inovação, INIAV—Instituto Nacional de Investigação Agrária e Veterinária, 2780-157 Oeiras, PortugalINOV.LINEA/TAGUSVALLEY—Science and Technology Park, 2200-062 Abrantes, PortugalLEAF—Linking Landscape, Environment, Agriculture and Food Research Center, Instituto Superior de Agronomia, Universidade de Lisboa, 1349-017 Lisboa, PortugalLEAF—Linking Landscape, Environment, Agriculture and Food Research Center, Instituto Superior de Agronomia, Universidade de Lisboa, 1349-017 Lisboa, PortugalUnidade de Tecnologia e Inovação, INIAV—Instituto Nacional de Investigação Agrária e Veterinária, 2780-157 Oeiras, PortugalSweet potato (<i>Ipomoea batatas</i> (L.) Lam.; SP) flour enhances food nutrition and bioactivity while functioning as a thickening/gelling agent. This study investigated the impact of two drying methods [hot-air (75 °C/20 h) and freeze-drying (−41–30 °C/70 h)] on the physical–functional properties of flours from three SP varieties: <i>Bonita</i> (white-fleshed), <i>Bellevue</i> (orange-fleshed), and <i>NP1648</i> (purple-fleshed). Particle size, morphology, water/oil absorption capacities (WAC/OAC), bulk density, swelling power (SwP), water solubility (WS), foaming/emulsifying properties, least gelation concentration (LGC), and gelatinisation temperature (GT) were analysed. Both the drying method and variety significantly influenced these properties. Hot-air-dried flours exhibited bimodal particle distribution, compact microstructure, and aggregated starch granules, yielding higher WAC (≈3.2 g/g) and SwP (≈3.6 g/g). Freeze-dried flours displayed smaller particles, porous microstructure, and fragmented granules, enhancing OAC (≈3.0 g/g) and foaming capacity (≈17.6%). GT was mainly variety-dependent, increasing as <i>Bellevue</i> (74.3 °C) < <i>NP1648</i> (78.5 °C) < <i>Bonita</i> (82.8 °C), all exceeding commercial potato starch (68.7 °C). <i>NP1648</i> required lower LGC (10% vs. 16% for others). All flours exhibited high WS (24–39.5%) and emulsifying capacity (≈44%). These results underscore the importance of selecting the appropriate drying method and variety to optimise SP flour functionality for targeted food applications. Freeze-dried flours might suit aerated/oil-retentive products, while hot-air-dried flours could be ideal for moisture-sensitive formulations.https://www.mdpi.com/1420-3049/30/8/1846hot-air dryingfreeze-dryingflour propertieswater absorption capacityoil absorption capacitygelation behaviour |
| spellingShingle | Nelson Pereira Ana Cristina Ramos Marco Alves Vítor D. Alves Margarida Moldão Marta Abreu Physical and Functional Properties of Sweet Potato Flour: Influence of Variety and Drying Method Molecules hot-air drying freeze-drying flour properties water absorption capacity oil absorption capacity gelation behaviour |
| title | Physical and Functional Properties of Sweet Potato Flour: Influence of Variety and Drying Method |
| title_full | Physical and Functional Properties of Sweet Potato Flour: Influence of Variety and Drying Method |
| title_fullStr | Physical and Functional Properties of Sweet Potato Flour: Influence of Variety and Drying Method |
| title_full_unstemmed | Physical and Functional Properties of Sweet Potato Flour: Influence of Variety and Drying Method |
| title_short | Physical and Functional Properties of Sweet Potato Flour: Influence of Variety and Drying Method |
| title_sort | physical and functional properties of sweet potato flour influence of variety and drying method |
| topic | hot-air drying freeze-drying flour properties water absorption capacity oil absorption capacity gelation behaviour |
| url | https://www.mdpi.com/1420-3049/30/8/1846 |
| work_keys_str_mv | AT nelsonpereira physicalandfunctionalpropertiesofsweetpotatoflourinfluenceofvarietyanddryingmethod AT anacristinaramos physicalandfunctionalpropertiesofsweetpotatoflourinfluenceofvarietyanddryingmethod AT marcoalves physicalandfunctionalpropertiesofsweetpotatoflourinfluenceofvarietyanddryingmethod AT vitordalves physicalandfunctionalpropertiesofsweetpotatoflourinfluenceofvarietyanddryingmethod AT margaridamoldao physicalandfunctionalpropertiesofsweetpotatoflourinfluenceofvarietyanddryingmethod AT martaabreu physicalandfunctionalpropertiesofsweetpotatoflourinfluenceofvarietyanddryingmethod |