Deep Dive Into the Effects of Food Processing on Limiting Starch Digestibility and Lowering the Glycemic Response

Abstract

During processing of cereal-based food products, starch undergoes dramatic changes. The objective of this work was to evaluate the impact of food processing on the starch digestibility profile of cereal-based foods using advanced imaging techniques, and to determine the effect of preserving starch in its native, slowly digestible form on its in vivo metabolic fate. Four different food products using different processing technologies were evaluated: extruded products, rusks, soft-baked cakes, and rotary-molded biscuits. Imaging techniques (X-ray diffraction, micro-X-ray microtomography, and electronic microscopy) were used to investigate changes in slowly digestible starch (SDS) structure that occurred during these different food processing technologies. For in vivo evaluation, International Standards for glycemic index (GI) methodology were applied on 12 healthy subjects. Rotary molding preserved starch in its intact form and resulted in the highest SDS content (28 g/100 g) and a significantly lower glycemic and insulinemic response, while the three other technologies resulted in SDS contents below 3 g/100 g. These low SDS values were due to greater disruption of the starch structure, which translated to a shift from a crystalline structure to an amorphous one. Modulation of postprandial glycemia, through starch digestibility modulation, is a meaningful target for the prevention of metabolic diseases.

Complementary Nutritional Improvements of Cereal-Based Products to Reduce Postprandial Glycemic Response

“…These additional improvements may be impactful in a longer-term effect but have not been shown to interfere with acute metabolic response [16]. According to previous studies on cereal-based products, the control products induced a medium GI due to their content of SDS and fat [40].…”

“…Indeed, it has been clearly shown for several years that food processes modify the starch structure configuration inside the food matrix depending on its level of gelatinization [16,39,41]. Several food processes used to make biscuits have been recently compared and showed that rotary molding technology which needs low water addition and smoother technological conditions is favorable to starch preservation in its native state by limiting starch gelatinization and maintaining a higher SDS content [40]. The originality of the present work is, that by using the same favorable technology (rotary molding), and by controlling some specific parts of the process, we were able to obtain a wide range of SDS, from 15 to 40% of available starch.…”

“…The main differences in food processes between the enriched biscuits and CMC were, the cooking duration and the treatment of the wheat flour used in the different formulas. For the CLC, the extrusion process was used which has been recognized as a unfavorable process to preserve native starch from gelatinization [40]. In the control biscuits, extruded wheat flour was used to increase starch gelatinization and therefore reduce the SDS content.…”

The impact of slowly digestible and resistant starch on glucose homeostasis and insulin resistance

“…These products were matched for the amount of available CHO by adapting products serving size to reach 50 g of available CHO for each. Products with the highest SDS content between 23.9 and 27.5 g/100 g induced the lowest glycemic responses, with the lowest incremental area under the curve (iAUC) 0–120 min of glucose and glycemic peak, associated with the lowest iAUC of insulin concentration [ 14 ]. A meta-analysis based on five studies using different SDS contents and matrices (SDS microspheres, pasta, breads, potatoes, biscuits, porridge) and culinary processes (boiling and cooling, rotary molding) over a single intake showed some discrepancies.…”

The Effects of Soluble Dietary Fibers on Glycemic Response: An Overview and Futures Perspectives

“…An interesting study using several imaging techniques (X-ray diffraction, micro-X-ray microtomography, and electronic microscopy) evaluated four food products produced with different processing technologies (extruded products, rusks, soft-baked cakes, and rotary-molded biscuits). It was possible to observe that the rotary-molded process preserved the higher content of slowly digestible starch and its crystalline structure, thus resulting in a lower glycemic and insulinemic response [ 29 ].…”