Starch digestibility in a food matrix depends on processing conditions that may affect its physical state and microstructure. Starch gelatinization is one critical change that takes place during frying which could be affected during low-pressure processing. This study assessed the effect of vacuum frying on starch gelatinization and its in vitro digestibility. Laminated dough was made of a reconstituted blend of wheat starch (88% d.b.) and gluten (12% d.b.). Samples were fried under vacuum (6.5 kPa, Twater-boiling-point = 38 °C) or atmospheric conditions up to bubble-end point, maintaining a thermal driving force of 70 °C (Toil - Twater-boiling-point = 70 °C). Vacuum fried samples showed less starch gelatinization (28%), less rapidly available glucose (27%), and more unavailable glucose (70%) than their atmospheric counterparts (which presented 99% starch gelatinization, 40% rapidly available glucose, and 46% unavailable glucose), and the values were close to those of raw dough. These results show how vacuum processing may be used to control the degree of starch gelatinization and related digestibility.
Bibliographical noteFunding Information:
The authors would like to acknowledge the financial support of CONICYT – Chile through the Human Capital Formation Advanced Program National Doctoral Fellowship 2013 (Folio 21130468), Anillo Project ACT1105/12: Healthy food matrix design and the School of Engineering from Pontificia Universidad Católica de Chile.
© 2015 Elsevier Ltd. All rights reserved.
- In vitro digestibility
- Starch digestibility
- Vacuum frying