Structural and enzyme kinetic studies of retrograded starch: Inhibition of α-amylase and consequences for intestinal digestion of starch.
Retrograded starch is known to be resistant to digestion. We used enzyme kinetic experiments to examine how retrogradation of starch affects amylolysis catalysed by porcine pancreatic amylase. Parallel studies employing differential scanning calorimetry, infra red spectroscopy, X-ray diffraction and NMR spectroscopy were performed to monitor changes in supramolecular structure of gelatinised starch as it becomes retrograded. The total digestible starch and the catalytic efficiency of amylase were both decreased with increasing evidence of retrogradation. A purified sample of retrograded high amylose starch inhibited amylase directly. These new findings demonstrate that amylase binds to retrograded starch. Therefore consumption of retrograded starch may not only be beneficial to health through depletion of total digestible starch, and therefore the metabolisable energy, but may also slow the rate of intestinal digestion through direct inhibition of α-amylase. Such physiological effects have important implications for the prevention and management of type 2 diabetes and cardiovascular disease.
King's College London, Faculty of Life Sciences and Medicine, Diabetes and Nutritional Sciences Division, Biopolymers Group, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, United Kingdom.
Hamung
H
Patel
King's College London, Faculty of Life Sciences and Medicine, Institute of Pharmaceutical Science, Drug Delivery Group, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, United Kingdom.
Paul G
PG
Royall
UCL School of Pharmacy, University College, 29-39 Brunswick Square, London WC1N 1AX, United Kingdom.
Simon
S
Gaisford
UCL School of Pharmacy, University College, 29-39 Brunswick Square, London WC1N 1AX, United Kingdom.
Gareth R
GR
Williams
King's College London, Faculty of Life Sciences and Medicine, Diabetes and Nutritional Sciences Division, Biopolymers Group, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, United Kingdom; Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, United Kingdom.
Cathrina H
CH
Edwards
Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, United Kingdom; Excellence in Plant Cell Walls, Centre for Nutrition and Food Sciences, Queensland Alliance for Agriculture and Food Innovation, University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia.
Frederick J
FJ
Warren
Excellence in Plant Cell Walls, Centre for Nutrition and Food Sciences, Queensland Alliance for Agriculture and Food Innovation, University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia.
Bernadine M
BM
Flanagan
King's College London, Faculty of Life Sciences and Medicine, Diabetes and Nutritional Sciences Division, Biopolymers Group, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, United Kingdom.
Peter R
PR
Ellis
King's College London, Faculty of Life Sciences and Medicine, Diabetes and Nutritional Sciences Division, Biopolymers Group, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, United Kingdom. Electronic address: peter.butterworth@kcl.ac.uk.
Peter J
PJ
Butterworth
D000688:Amylose; D000818:Animals; D004063:Digestion; D007700:Kinetics; D013213:Starch / Q000378:metabolism*; D013552:Swine; D000516:alpha-Amylases / Q000378:metabolism*
D013213:Starch; D000688:Amylose; D000516:alpha-Amylases
Amylase inhibition; FTIR-ATR; MC-DSC; Starch retrogradation; XRD