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The Reactivity of Porcine Pancreatic alpha‐Amylase Towards Native, Defatted and Heat‐moisture Treated Potato Starches Before and After Hydroxypropylation
Author(s) -
Perera C.,
Hoover H.
Publication year - 1998
Publication title -
starch ‐ stärke
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.62
H-Index - 82
eISSN - 1521-379X
pISSN - 0038-9056
DOI - 10.1002/(sici)1521-379x(199805)50:5<206::aid-star206>3.0.co;2-r
Subject(s) - granule (geology) , amylase , chemistry , moisture , hydrolysis , starch , potato starch , food science , propylene oxide , nuclear chemistry , biochemistry , enzyme , organic chemistry , materials science , copolymer , ethylene oxide , polymer , composite material
Abstract Potato starch was defatted (hot 75% n‐propanol) and heat‐moisture treated (100°C, 30% moisture) for various time intervals. The results showed that the above treatments increased the susceptibility of potato starch granules (heat‐moisture treated > defatted) towards hydrolysis by porcine pancreatic α‐amylase. These differences can be accounted for by the structural changes that occur within the amorphous and crystalline regions of the starch granule during defatting and heat‐moisture treatment. Native, defatted (7 h) and heat‐moisture treated (100°C, 30% moisture, 16 h) potato starches were hydroxypropylated (to different levels of molar substitution [MS]) with propylene oxide (2 → 20 %). The results showed that the alkaline reagents (NaOH and Na 2 SO 4 ) used during hydroxypropylation increased the susceptibility of the above starches (native > defatted > heat‐moisture treated) towards hydrolysis by α‐amylase. Addition of propylene oxide to alkali treated starches, further enhanced their susceptibility, towards α‐amylase. However, granule susceptibility towards α‐amylase did not increase exponentially with increase in MS. The extent of hydrolysis began to decrease at MS levels of 0.29 (native), 0.28 (heat‐moisture treated) and 0,26 (defatted).