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Aging Effects on Sorbitol‐ and Non‐Crystallizing Sorbitol‐Plasticized Tapioca Starch Films
Author(s) -
Thirathumthavorn Doungjai,
Charoenrein Sanguansri
Publication year - 2007
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/star.200700626
Subject(s) - plasticizer , sorbitol , starch , materials science , crystallinity , ultimate tensile strength , crystallization , composite material , elongation , chemical engineering , polymer chemistry , chemistry , food science , engineering
The effect of aging on the properties of tapioca starch films plasticized with either sorbitol (S) or non‐crystallizing sorbitol (NCS) was investigated in this study. Tapioca starch, plasticizer and deionized water were mixed, heated, cast on high‐density polyethylene plates and dried at ambient conditions. The results showed that S was more effective in plasticizing fresh starch film than NCS. However, sorbitol crystallization was observed in S‐plasticized starch film after one month of storage, while there was no crystallization observed in NCS‐plasticized starch film after two months of storage. Mechanical properties of both S‐ and NCS‐plasticized starch films changed significantly with time, but with less change in the NCS‐plasticized films. Tensile strength, elastic modulus and toughness increased over time; conversely, elongation decreased. Additionally, the water vapor transmission rate decreased as storage time increased. The fact that mechanical properties of both S‐ and NCS‐plasticized films changed is likely due to an increase in crystallinity of the starch in the films with time.