Impact of hydrothermal treatments on the functional, thermal, pasting, morphological and rheological properties of underutilized yam starches

• Published in: Journal of food measurement & characterization 2023-06, Vol.17 (3), p.2285-2300
• Main Authors: Bora, Jinku, Mahnot, Nikhil Kumar, Makroo, Hilal Ahmad, Mahanta, Charu Lata
• Format: Article
• Language: English
• Subjects: Amylose; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Digestibility; Dioscorea esculenta; Engineering; Enthalpy; Food Science; Heat treatment; Hydrothermal treatment; Leaching; Moisture effects; Molecular interactions; Morphology; Non Newtonian flow; Pastes; Research Paper; Rheological properties; Rheology; Shear thinning (liquids); Starch; Starches; Viscosity
• ISSN: 2193-4126; 2193-4134
• DOI: 10.1007/s11694-022-01789-1

Starches from two yam species, viz. Dioscorea alata and Dioscorea esculenta  were subjected to heat moisture treatment (HMT) with 20 and 30% moisture at 110 °C for 3 h and annealing (ANN) at 1:2 and 1:4 starch to water ratio and 50 °C for 24 h, and their effect on functional, thermal, pasting, morphological, and rheological properties, and in vitro digestibility was investigated. HMT and ANN modifications decreased the swelling and solubility of the starches compared to the native starches. D. alata showed a higher amylose leaching than D. esculenta due to its higher amylose content. An increase in the transition enthalpy (∆H) after ANN and a decrease in ∆H after HMT were observed. ANN modification increased the setback viscosity, while HMT modification decreased the setback viscosity compared to the corresponding native starches of both the species. Both HMT and ANN decreased the peak viscosity, hot paste viscosity and breakdown viscosity of the starch granules. The steady shear and dynamic rheological properties of the starch paste at 25 °C were evaluated by the power-law model and indicated non-Newtonian flow properties with shear-thinning behaviour. ANN modified starch exhibited a greater impact than HMT on the rheological properties, indicating stronger molecular interactions in the pastes. An increase in slowly digestible and resistant starch with a decrease in rapidly digestible starch was noticed after HMT and ANN modifications.