Abstract
Background and objectives:
The sequence in which modifications are applied is known to impact the characteristics of starch. The objective of this study was to determine which sequence of annealing (prior or post) could lead to improved properties of diesterified crosslinked and substituted OSA-modified potato starch extracted from the Lady rosetta variety.
Methods:
The impact of prior and post annealing on crosslinked and OSA-modified potato starch was investigated in terms of dynamic rheology, percent crystallinity and in vitro digestibility.
Resullts
Irrespective of the sequence of modifications employed, all potato starches were observed to have B-type crystallites. However, the amount of crystallinity differed with respect to the sequence of modifications as well as the type of modification. The crystallinity was observed to be the lowest for native starch (19.18%), but prior annealing of OSA-modified starch resulted in higher crystallinity, at 34.52%. For crosslinked potato starch, post annealing resulted in the highest crystallinity, at 35.10%. The RS content was closely related to crystallinity. Post-annealed crosslinked starch, which exhibited the highest crystallinity, also showed the highest RS content at 54.30%, while native starch, which had the lowest crystallinity, was observed to have the lowest RS content at 18.28%. Annealing increased the phase angle of crosslinked and OSA-modified starches. However, the extent of the increase in phase angle was higher in the case of pre-annealing of OSA-modified and post-annealing of crosslinked starches.
Conclusion:
The high-RS potato starches developed in this study can be used to prepare low-glycemic products as the FDA has declared RS as a synthetic fiber.
Significance and novelty:
The impact of prior and post annealing on crosslinked and OSA-modified potato starch has never been studied before. The sequence of annealing had very different results for crosslinked and OSA-modified potato starch. In the case of crosslinking, post annealing resulted in more significant changes in techno-functional properties, while in the case of OSA, it was prior annealing.
