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

Gautier Cesbron-Lavau,Alexandra Meynier,Fiona Atkinson,Aurélie Goux,Sophie Vinoy

doi:10.3390/nu13020381

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.

Highlights

There has been increasing attention on food processing methods, as transforming food products can modify the physiological fate of their components
We showed that rotary molding better preserves starch in its native state and slows its digestion, which led to a significantly lower glycemic index (GI) and insulin index (II) compared to the other three processing technologies studied
The imaging techniques used in this study provide new, complementary descriptions of starch within the food products: microscopy imaging provided surface information; tomography analysis generated a layer-by-layer view of the products; and crystallography provided information on the structural properties of the starch

Summary

Introduction

There has been increasing attention on food processing methods, as transforming food products can modify the physiological fate of their components. Since the food processing industry began to play a significant role in food production, processed foods have formed a significant part of our daily diets [3]. Food starch is derived from cereals (e.g., wheat, maize, rice, barley, and buckwheat), tubers (e.g., potatoes and cassava) and legumes (e.g., peas, lentils, kidney beans, and mung beans). It consists of a semi-crystalline material produced by plants that forms roughly spherical granules in plant tissues [4]. The digestibility of starch in its natural state varies greatly depending on these variables [7,8,9]

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