Abstract
Purpose: To investigate the effects of dry heat, microwave and ultrasonic treatments on the physicochemical properties of potato starch alone or blended with pectin.
 Methods: The physicochemical properties of potato starch gels prepared using microwave, ultrasonic and dry heat treatments were assessed. Pasting properties, gel strength, thermal properties and crystal texture of the potato starch were determined using Rapid Visco analyzer, texture profile analyzer, differential scanning calorimeter and x-ray diffractometer.
 Results: Dry heat and ultrasonic treatments significantly increased the peak viscosity of the potato starch, and significantly decreased its setback and pasting temperatures (p < 0.05). Dry heat treatment significantly increased the hardness, while dry heat and ultrasonic treatments significantly improved retrogradation of the potato starch (p < 0.05). Transparency of potato starch paste was significantly increased by the different treatments, except microwave treatment (p < 0.05). Potato starch gels blended with pectin and subjected to any of the treatments exhibited significantly increased hardness, when compared with raw potato starch (p < 0.05). The retrogradation of the potato starch was significantly improved by the different treatments. Dry heat and ultrasonic treatments significantly decreased the syneresis of potato starch with or without pectin (p < 0.05). The three treatments also significantly affected the gelatinization enthalpy of the potato starch with or without pectin, and exerted some effects on the crystallinity of the gels.
 Conclusion: The results obtained in this study suggest that differences in physicochemical properties of potato starch gels are due mainly to the degree of damage to starch granules caused by different treatments. The addition of pectin to potato starch gel greatly improves its hardness and retrogradation.
Highlights
Potato starch, a tuber starch accounts for about 6 % of global starch production, and it is ranked third in the world based on its usefulness
The results obtained in this study suggest that changes in crystalline structures of potato starch with or without pectin when subjected to different treatments may have led to a significant reduction in the amount of energy required for disrupting the H-bonds within junction zones
The structure of the starch molecule may have been damaged during these treatments, or the starch granules may have been encased in a layer of pectin or some reactions occurred with pectin, so that gelatinization of the starch became more difficult
Summary
A tuber starch accounts for about 6 % of global starch production, and it is ranked third in the world based on its usefulness. Potato starch is characterized by low gelatinization temperature, large particle diameter, high paste viscosity and high paste transparency. Amylose makes up 23.2 % of potato starch, and it is characterized by high swelling force (19.0 g/g), [1]. Potato starch alone or blended with pectin. Blends of starch and non-starch polysaccharide hydrocolloids are used as raw or auxiliary materials for food or drug production, because they have different effects on starch gelatinization, viscosity, flow performance and aging properties of binary gels [2,3]. The key factors that control the formation and properties of a binary gel include molecular weight of the components, polydispersity and proportion of amylose in the starch. The effects of molecular weight and polydispersity on thermodynamic compatibility of polysaccharide ligands interacting with each other can be seen from their effects on water activity in solution [4]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
