α-Amylase action on starch in chickpea flour following hydrothermal processing and different drying, cooling and storage conditions

• Published in: Carbohydrate polymers 2021-05, Vol.259, p.117738-117738, Article 117738
• Main Authors: Edwards, Cathrina H., Veerabahu, Amalia S., Mason, A. James, Butterworth, Peter J., Ellis, Peter R.
• Format: Article
• Language: English
• Subjects: alpha-Amylases - metabolism; Cicer - metabolism; Desiccation; Digestion; Flour - analysis; Food Storage; Kinetics; Log of slope analysis; Magnetic Resonance Spectroscopy; Resistant starch; Solid-state 13C CP-MS NMR; Starch - chemistry; Starch - metabolism; Starch digestion; α-Amylase action
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2021.117738

[Display omitted] •α-Amylase action on legume starch varied after different processing and storage regimes.•Susceptibility to amylolysis linked to double-helical order as measured by 13C NMR.•Chilling of gelatinised starch increased retrogradation and decreased digestion.•Air-dried gelatinised starch markedly decreased the rate and extent of amylolysis.•Various processing and storage strategies can lower starch digestion of ready-meals. Starch is present in many prepared ‘ready-meals’ that have undergone processing and/or storage in frozen or chilled state. Hydrothermal processing greatly increases starch digestibility and postprandial glycaemia. Effects of different heating/drying and cooling regimes on amylolysis have received little attention. Hence, we examined the effects of different processing treatments on in vitro digestibility of starch in chickpea flour. Solid-state 13C NMR was used to estimate ordered double-helical structure in the starch. Native starch with 25 % double-helical content was the most resistant to digestion but hydrothermal processing (gelatinisation) resulted in >95 % loss of order and a large increase in starch digestibility. Air-drying of pre-treated flour produced slowly-digestible starch (C∞, 55.9 %). Refrigeration of gelatinised samples decreased ease of amylolysis coincident with increase in double-helical content. Freezing maintained the same degree of digestibility as freshly gelatinised material and produced negligible retrogradation. Chilling may be exploited to produce ready-meals with a lower glycaemic response.