This study investigates the effect of different processing methods (boiling, baking, and frying) on the functional properties, physicochemical characteristics and in vitro starch digestibility of two sweet potato varieties: Guayaco morado and Toquecita. Thermal processing affected the rate of starch digestion, focusing on parameters, such as total digestible starch (TDS), rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS), from which the hydrolytic index was determined and allowed estimation of the glycemic index (pGI) to be derived from sweet potato intake. Each cooking technique has a unique impact on sweet potatoes. For example, boiling maximizes starch gelatinization (improving digestibility) but leaches water soluble nutrients, baking develops desirable flavors and retains carotenoids, although high temperatures can form acrylamide and frying increases resistant starch which reduces glycemic impact, it also leads to decreased starch solubility and creates crisp textures but introduces excess calories and potential heat contaminants. Among the varieties studied, Toquecita exhibited higher TDS (73.75 ± 0.18 g/100 g dw) and RDS (31.21 ± 0.10 g/100 g dw) in boiled samples, while fried samples showed a higher RS content (9.83 ± 0.03) compared to Guayaco morado. This difference reflects Toquecita's lower amylose content and water absorption index. Both varieties exhibited a lower glycemic index (pGI) in the raw state. However, among the processed samples, the fried Guayaco morado variety displayed a lower pGI (64.15 ± 0.89). These results emphasize the significant impact of cooking methods on the nutritional profile of sweet potato starch. The findings suggest that boiling and baking are processes for enhancing starch digestibility, while frying may diminish it. Overall, this study highlights the potential of sweet potatoes as a functional food ingredient, particularly for diets with a moderate glycemic index.
Citation: Christian Villegas, Elena Villacrés, María Quelal, María Morales. Effect of processing on functional properties, physicochemical characteristics and in vitro starch digestibility of two sweet potato varieties[J]. AIMS Agriculture and Food, 2025, 10(3): 698-715. doi: 10.3934/agrfood.2025035
This study investigates the effect of different processing methods (boiling, baking, and frying) on the functional properties, physicochemical characteristics and in vitro starch digestibility of two sweet potato varieties: Guayaco morado and Toquecita. Thermal processing affected the rate of starch digestion, focusing on parameters, such as total digestible starch (TDS), rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS), from which the hydrolytic index was determined and allowed estimation of the glycemic index (pGI) to be derived from sweet potato intake. Each cooking technique has a unique impact on sweet potatoes. For example, boiling maximizes starch gelatinization (improving digestibility) but leaches water soluble nutrients, baking develops desirable flavors and retains carotenoids, although high temperatures can form acrylamide and frying increases resistant starch which reduces glycemic impact, it also leads to decreased starch solubility and creates crisp textures but introduces excess calories and potential heat contaminants. Among the varieties studied, Toquecita exhibited higher TDS (73.75 ± 0.18 g/100 g dw) and RDS (31.21 ± 0.10 g/100 g dw) in boiled samples, while fried samples showed a higher RS content (9.83 ± 0.03) compared to Guayaco morado. This difference reflects Toquecita's lower amylose content and water absorption index. Both varieties exhibited a lower glycemic index (pGI) in the raw state. However, among the processed samples, the fried Guayaco morado variety displayed a lower pGI (64.15 ± 0.89). These results emphasize the significant impact of cooking methods on the nutritional profile of sweet potato starch. The findings suggest that boiling and baking are processes for enhancing starch digestibility, while frying may diminish it. Overall, this study highlights the potential of sweet potatoes as a functional food ingredient, particularly for diets with a moderate glycemic index.
| [1] | Cobeña Ruiz G, Cañarte Bermúdez E, Mendoza García A, et al. (2017) Manual técnico del cultivo de camote. INIAP EXP Portoviejo. Edited by E.I.E.E.P. Ecuador: Portoviejo, 1–89. http://repositorio.iniap.gob.ec/handle/41000/4789 |
| [2] |
Teow CC, Truong V, McFeeters RF, et al. (2007) Antioxidant activities, phenolic and β-carotene contents of sweet potato genotypes with varying flesh colours. Food Chem 103: 829–838. https://doi.org/10.1016/j.foodchem.2006.09.033 doi: 10.1016/j.foodchem.2006.09.033
|
| [3] |
Xu J, Su X, Lim S, et al. (2015) Characterisation and stability of anthocyanins in purple-fleshed sweet potato P40. Food Chem 186: 90–96. https://doi.org/10.1016/j.foodchem.2014.08.123 doi: 10.1016/j.foodchem.2014.08.123
|
| [4] |
Das S, Gazdag Z, Szente L, et al. (2019) Antioxidant and antimicrobial properties of randomly methylated β cyclodextrin—Captured essential oils. Food Chem 278: 305–313. https://doi.org/10.1016/j.foodchem.2018.11.047 doi: 10.1016/j.foodchem.2018.11.047
|
| [5] |
Kim, HR, Hong JS, Ryu AR, et al. (2020) Combination of rice varieties and cooking methods resulting in a high content of resistant starch. Cereal Chem 97: 149–157. https://doi.org/https://doi.org/10.1002/cche.10221 doi: 10.1002/cche.10221
|
| [6] |
Mert B, Demirkesen I (2016) Reducing saturated fat with oleogel/shortening blends in a baked product. Food Chem 199: 809–816. https://doi.org/10.1016/j.foodchem.2015.12.087 doi: 10.1016/j.foodchem.2015.12.087
|
| [7] |
Dinu M, Soare R, Babeanu C, et al. (2018) Analysis of nutritional composition and antioxidant activity of sweet potato (Ipomoea batatas L.) leaf and petiole. J Appl Bot Food Quality 91: 120–125. https://doi.org/https://doi.org/10.5073/JABFQ.2018.091.017 doi: 10.5073/JABFQ.2018.091.017
|
| [8] |
Oyetayo FL, Akomolafe SF, Osesanmi TJ (2020) Effect of dietary inclusion of pumpkin (Cucurbita pepo L) seed on nephrotoxicity occasioned by cisplatin in experimental rats. J Food Biochem 44: 1–11. https://doi.org/10.1111/jfbc.13439 doi: 10.1111/jfbc.13439
|
| [9] |
Samarakoon ERJ (2020) Impact of physical modifications on starch nutritional fractions: rapidly digestible starch, slowly digestible starch and resistant starch. J Food Bioact 12: 106–121. https://doi.org/10.31665/JFB.2020.12249 doi: 10.31665/JFB.2020.12249
|
| [10] |
Zhu F (2017) Structures, properties, modifications, and uses of oat starch. Food Chem 229: 329–340. https://doi.org/10.1016/j.foodchem.2017.02.064 doi: 10.1016/j.foodchem.2017.02.064
|
| [11] |
Kim HJ, Woo KS, Lee HU, et al. (2020) Physicochemical characteristics of starch in sweet potato cultivars grown in Korea. Prev Nutr Food Sci 25: 212–218. https://doi.org/10.3746/pnf.2020.25.2.212 doi: 10.3746/pnf.2020.25.2.212
|
| [12] |
Englyst HN, Veenstra J, Hudson GJ (1996) Measurement of rapidly available glucose (RAG) in plant foods: A potential in vitro predictor of the glycaemic response. Br J Nutr 75: 327–337. https://doi.org/https://doi.org/10.1079/BJN19960137 doi: 10.1079/BJN19960137
|
| [13] |
Mulla MZ, Annapure US, Bharadwaj VR, et al. (2017) A study on the kinetics of acrylamide formation in banana chips. J Food Proc Preserv 41: e12739. https://doi.org/10.1111/jfpp.12739 doi: 10.1111/jfpp.12739
|
| [14] |
Bello‐Perez LA, Flores-Silva PC, Agama-Acevedo E, et al. (2020) Starch digestibility: Past, present, and future. J Sci Food Agric 100: 5009–5016. https://doi.org/https://doi.org/10.1002/jsfa.8955 doi: 10.1002/jsfa.8955
|
| [15] |
Wang X, Kristo E, LaPointe G (2019) The effect of apple pomace on the texture, rheology and microstructure of set type yogurt. Food Hydrocolloids 91: 83–91. https://doi.org/10.1016/j.foodhyd.2019.01.004 doi: 10.1016/j.foodhyd.2019.01.004
|
| [16] |
Liang J, Yu S, Li Z, et al. (2025) Effect of plasma manipulation on the developing quick-cooking and the hydration promotion of adzuki bean. Int J Food Sci Technol 60: vvae023. https://doi.org/10.1093/ijfood/vvae023 doi: 10.1093/ijfood/vvae023
|
| [17] |
Abiche MG, Teferi MB, Olbamo SK (2019) Determination of glycemic index and glycemic loads of commonly consumed food items of cassava and sweet potato of Bench Maji Zone, South West Ethiopia 2017. Int J Biochem Res Rev 26: 1–12. https://doi.org/10.9734/ijbcrr/2019/v26i430104 doi: 10.9734/ijbcrr/2019/v26i430104
|
| [18] |
Li C, Hu Y (2022) In vitro and animal models to predict the glycemic index value of carbohydrate-containing foods. Trends Food Sci Technol 120: 16–24. https://doi.org/https://doi.org/10.1016/j.tifs.2021.12.031 doi: 10.1016/j.tifs.2021.12.031
|
| [19] |
Ngo T, Van Kunyanee K, Luangsakul N (2023) Insights into recent updates on factors and technologies that modulate the glycemic index of rice and its products. Foods 12: 3659. https://doi.org/https://doi.org/10.3390/foods12193659 doi: 10.3390/foods12193659
|
| [20] |
Lal MK, Singh B, Sharma S, et al. (2021) Glycemic index of starchy crops and factors affecting its digestibility: A review. Trends Food Sci Technol 111: 741–755. https://doi.org/10.1016/j.tifs.2021.02.067 doi: 10.1016/j.tifs.2021.02.067
|
| [21] |
Seah JYH, Koh WP, Yuan JM, et al. (2019) Rice intake and risk of type 2 diabetes: the Singapore Chinese Health Study. Eur J Nutr 58: 3349–3360. https://doi.org/https://doi.org/10.1007/s00394-018-1879-7 doi: 10.1007/s00394-018-1879-7
|
| [22] |
Cornejo F, Salazar R, Martínez-Espinosa R, et al. (2022) Evaluation of starch digestibility of Andean crops oriented to healthy diet recommendation. Int J Food Prop 25: 1146–1155. https://doi.org/https://doi.org/10.1080/10942912.2022.2074036 doi: 10.1080/10942912.2022.2074036
|
| [23] | Eddie ZZ, Park CH, Gloria CR (2024) CAPÍTULO 6—VARIABILIDAD GENÉTICA DEL CAMOTE. In: Gloria C, Xavier OD, Luis DG, et al. (Eds.), Cultivo de camote en Ecuador, CIDEPRO., Portoviejo, Manabí, Ecuador: INIAP-KOPIA, 135: 83–104. Available from: http://repositorio.iniap.gob.ec/handle/41000/6307 |
| [24] |
Villacrés E, Manosalvas L, Simbaña K, et al. (2025) Effect of vacuum frying on changes in the quality attributes of three varieties of maize. Int J Food Sci Technol 60: vvae039. https://doi.org/https://doi.org/10.1093/ijfood/vvae039 doi: 10.1093/ijfood/vvae039
|
| [25] |
Anderson RA, Conway HF, Peplinski AJ (1970) 'Gelatinization of corn grits by roll cooking, extrusion cooking and steaming. Starch-Stärke 22: 130–135. https://doi.org/https://doi.org/10.1002/star.19700220408 doi: 10.1002/star.19700220408
|
| [26] |
Calderón C, Quelal M, Villacrés E, et al. (2023) 'Impact of extrusion on the physicochemical parameters of two varieties of corn (Zea mays). AIMS Agric Food 8: 873–888. https://doi.org/10.3934/agrfood.2023046 doi: 10.3934/agrfood.2023046
|
| [27] | Official Methods of Analysis of the AOAC (2005) Association of Official Analytical Chemists (AOAC). 18th ed. Washington DC, USA: A.O.A.C. Available from: https://www.scirp.org/reference/ReferencesPapers?ReferenceID = 2033299. |
| [28] |
Waidyarathna GRNN, Ekanayake S, Chandrasekara A (2021) Comparative analysis of nutrient composition and glycaemic indices of nine sweet potatoes (Ipomoea batatas) varieties. Int J Biol Chem Sci 15: 1410–1420. https://doi.org/10.4314/ijbcs.v15i4.9 doi: 10.4314/ijbcs.v15i4.9
|
| [29] |
Morrison WR, Laignelet B (1983) An improved colorimetric procedure for determining apparent and total amylose in cereal and other starches. J Cereal Sci 1: 9–20. https://doi.org/10.1016/S0733-5210(83)80004-6 doi: 10.1016/S0733-5210(83)80004-6
|
| [30] |
Dias FFG, Bogusz S, Hantao LW, et al. (2017) Acrylamide mitigation in French fries using native l-asparaginase from Aspergillus oryzae CCT 3940. LWT-Food Sci Technol 76: 222–229. https://doi.org/https://doi.org/10.1016/j.lwt.2016.04.017 doi: 10.1016/j.lwt.2016.04.017
|
| [31] |
Sun X, Yu C, Fu M, et al. (2019) Extruded whole buckwheat noodles: Effects of processing variables on the degree of starch gelatinization, changes of nutritional components, cooking characteristics and in vitro starch digestibility. Food Funct 10: 6362–6373. https://doi.org/10.1039/C9FO01111K doi: 10.1039/C9FO01111K
|
| [32] |
Samotus B, Tuz J, Doerre E (2014) Evaluation of Blue Value in different plant materials as a tool for rapid starch determination. Acta Soc Bot Pol 62: 137–141. https://doi.org/https://doi.org/10.5586/asbp.1993.020 doi: 10.5586/asbp.1993.020
|
| [33] |
Jameel MR, Ansari Z, Al-Huqail AA, et al. (2022) CRISPR/Cas9-mediated genome editing of soluble starch synthesis enzyme in rice for low glycemic index. Agronomy 12: 2206. https://doi.org/https://doi.org/10.3390/agronomy12092206 doi: 10.3390/agronomy12092206
|
| [34] |
Goñi I, Garcia-Alonso A, Saura-Calixto F (1997) A starch hydrolysis procedure to estimate glycemic index. Nutr Res 17: 427–437. https://doi.org/10.1016/S0271-5317(97)00010-9 doi: 10.1016/S0271-5317(97)00010-9
|
| [35] | Megazyme International Ireland (2024) Resistant Starch Assay Kit. Available from: https://www.megazyme.com/resistant-starch-assay-kit-rapid. |
| [36] | Di Rienzo JA, Casanoves F, Balzarini MG, et al. (2020) InfoStat, versión 2020. Córdoba-Argentina: Grupo InfoStat, FCA, Universidad Nacional de Córdoba. Available from: https://www.infostat.com.ar/index.php?mod = page & id = 46. |
| [37] |
Roa Acosta DF, Solanilla‐Duque GS, Agudelo Laverde LM, et al. (2020) Structural and thermal properties of the amaranth starch granule obtained by high-impact wet milling. Int J Food Eng 16: 0024. https://doi.org/10.1515/ijfe-2020-0024 doi: 10.1515/ijfe-2020-0024
|
| [38] |
Chang Q, Zheng B, Zhang Y, et al. (2021) A comprehensive review of the factors influencing the formation of retrograded starch. Int J Biological Macromol 186: 163–173. https://doi.org/10.1016/j.ijbiomac.2021.07.050 doi: 10.1016/j.ijbiomac.2021.07.050
|
| [39] |
Liu X, Huang S, Chao C, et al. (2022) Changes of starch during thermal processing of foods: Current status and future directions. Trends Food Sci Technol 119: 320–337. https://doi.org/10.1016/j.tifs.2021.12.011 doi: 10.1016/j.tifs.2021.12.011
|
| [40] |
Zhuang Y, Wang Y, Yang H (2024) Effects of cation valence on swelling power, solubility, pasting, gel strength characteristics of potato starch. Food Chem 434: 137510. https://doi.org/10.1016/j.foodchem.2023.137510 doi: 10.1016/j.foodchem.2023.137510
|
| [41] |
Zhao J, Chen Z, Jin Z, et al. (2015) Effects of granule size of cross-linked and hydroxypropylated sweet potato starches on their physicochemical properties. J Agric Food Chem 63: 4646–4654. https://doi.org/10.1021/jf506349w doi: 10.1021/jf506349w
|
| [42] |
Zhong Y, Zhu H, Liang W, et al. (2018) High-amylose starch as a new ingredient to balance nutrition and texture of food. J Cereal Sci 81: 8–14. https://doi.org/10.1016/j.jcs.2018.02.009 doi: 10.1016/j.jcs.2018.02.009
|
| [43] |
Allan MC, Marinos N, Johanningsmeier SD, et al. (2021) Relationships between isolated sweetpotato starch properties and textural attributes of sweetpotato French fries. J Food Sci 86: 1819–1834. https://doi.org/10.1111/1750-3841.15725 doi: 10.1111/1750-3841.15725
|
| [44] |
Shi M, Li D, Yan Y, et al. (2018) Effect of moisture content on structure and properties of fried potato starch. Starch-Stärke 70: 1800012. https://doi.org/10.1002/star.201800012 doi: 10.1002/star.201800012
|
| [45] |
Chen L, Tian Y, Bai Y, et al. (2018) Effect of frying on the pasting and rheological properties of normal maize starch. Food Hydrocolloids 77: 85–95. https://doi.org/10.1016/j.foodhyd.2017.09.024 doi: 10.1016/j.foodhyd.2017.09.024
|
| [46] |
Yang Z, Hao H, Wu Y, et al. (2021) Influence of moisture and amylose on the physicochemical properties of rice starch during heat treatment. Int J Biol Macromol 168: 656–662. https://doi.org/10.1016/j.ijbiomac.2020.11.122 doi: 10.1016/j.ijbiomac.2020.11.122
|
| [47] |
Beech D, Beech J, Gould J, et al. (2022) Effect of amylose/amylopectin ratio and extent of processing on the physical properties of expanded maize starches. Int J Food Sci Technol 57: 2298–2309. https://doi.org/10.1111/ijfs.15581 doi: 10.1111/ijfs.15581
|
| [48] |
Wei S, Lu G, Cao H (2017) Effects of cooking methods on starch and sugar composition of sweetpotato storage roots. PLOS ONE 12: e0182604. https://doi.org/10.1371/journal.pone.0182604 doi: 10.1371/journal.pone.0182604
|
| [49] |
Zhang R, Chen H, Chen Y, et al. (2023) Impact of different cooking methods on the flavor and chemical profile of yellow-fleshed table-stock sweetpotatoes (Ipomoea batatas L.). Food Chem: X 17: 100542. https://doi.org/10.1016/j.fochx.2022.100542 doi: 10.1016/j.fochx.2022.100542
|
| [50] |
Majzoobi M, Farahnaky A (2021) Granular cold-water swelling starch; properties, preparation and applications, a review. Food Hydrocolloids 111: 106393. https://doi.org/10.1016/j.foodhyd.2020.106393 doi: 10.1016/j.foodhyd.2020.106393
|
| [51] |
Dehghannya J, Ngadi M (2021) Recent advances in microstructure characterization of fried foods: Different frying techniques and process modeling. Trends Food Sci Technol 116: 786–801. https://doi.org/10.1016/j.tifs.2021.03.033 doi: 10.1016/j.tifs.2021.03.033
|
| [52] |
Qadir N, Wani IA (2022) In-vitro digestibility of rice starch and factors regulating its digestion process: A review. Carbohydr Polym 291: 119600. https://doi.org/10.1016/j.carbpol.2022.119600 doi: 10.1016/j.carbpol.2022.119600
|
| [53] |
Li X, Wang L, Tan B, et al. (2024) Effect of structural characteristics on the physicochemical properties and functional activities of dietary fiber: A review of structure-activity relationship. Int J Biol Macromol 269: 132214. https://doi.org/10.1016/j.ijbiomac.2024.132214 doi: 10.1016/j.ijbiomac.2024.132214
|
| [54] |
Ochoa-Martínez LA, Luna Solís HA, Bermúdez Quiñones G (2021) Almidón de camote: Modificaciones enzimáticas, físicas y químicas. TECNOCIENCIA Chihuahua 15: 221–233. https://doi.org/10.54167/tecnociencia.v15i3.854 doi: 10.54167/tecnociencia.v15i3.854
|
| [55] |
Nagy R, Máthé E, Csapó J, et al. (2020) Modifying effects of physical processes on starch and dietary fiber content of foodstuffs. Processes 9: 17. https://doi.org/10.3390/pr9010017 doi: 10.3390/pr9010017
|
| [56] |
Leite CEC, Souza BDKF, Manfio CE, et al. (2022) Sweet potato new varieties screening based on morphology, pulp color, proximal composition, and total dietary fiber content via factor analysis and principal component analysis. Front Plant Sci 13: 852709. https://doi.org/10.3389/fpls.2022.852709 doi: 10.3389/fpls.2022.852709
|
| [57] |
Wang, Y. Chen L, Yang T, et al. (2021) A review of structural transformations and properties changes in starch during thermal processing of foods. Food Hydrocolloids 113: 106543. https://doi.org/10.1016/j.foodhyd.2020.106543 doi: 10.1016/j.foodhyd.2020.106543
|
| [58] |
Chi C, Li X, Lu P, et al. (2019) Dry heating and annealing treatment synergistically modulate starch structure and digestibility. Int J Biological Macromol 137: 554–561. https://doi.org/https://doi.org/10.1016/j.ijbiomac.2019.06.137 doi: 10.1016/j.ijbiomac.2019.06.137
|
| [59] |
Krishnan V, Mondal D, Thomas B, et al. (2021) Starch-lipid interaction alters the molecular structure and ultimate starch bioavailability: A comprehensive review. Int J Biol Macromol 182: 626–638. https://doi.org/https://doi.org/10.1016/j.ijbiomac.2021.04.030 doi: 10.1016/j.ijbiomac.2021.04.030
|
| [60] |
Guo L, Tao H, Cui B, et al. (2019) The effects of sequential enzyme modifications on structural and physicochemical properties of sweet potato starch granules. Food Chem 277: 504–514. https://doi.org/10.1016/j.foodchem.2018.11.014 doi: 10.1016/j.foodchem.2018.11.014
|
| [61] |
Vernaza MG, Chang YK (2017) Survival of resistant starch during the processing of atmospheric and vacuum fried instant noodles. Food Sci Technol 37: 425–431. https://doi.org/10.1590/1678-457x.17716 doi: 10.1590/1678-457x.17716
|
| [62] |
De Oliveira AF, Soares JM, da Silva EC, et al. (2019) Evaluation of the chemical, physical and nutritional composition and sensory acceptability of different sweet potato cultivars. Semina: Ciências Agrárias 40: 1127. https://doi.org/https://doi.org/10.5433/1679-0359.2019v40n3p1127 doi: 10.5433/1679-0359.2019v40n3p1127
|
Christian Villegas, Elena Villacrés, María Quelal, María Morales. Effect of processing on functional properties, physicochemical characteristics and in vitro starch digestibility of two sweet potato varieties[J]. AIMS Agriculture and Food, 2025, 10(3): 698-715. doi: 10.3934/agrfood.2025035
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