A low glycemic index corn flour and its characteristics

Abstract

The application discloses low-glycemic-index corn flour and belongs to the technical field of food. The corn flour is prepared from ordinary corn through a pure physical annealing process and meets the following characteristics: a GI value is less than or equal to 55, a RS3 type resistant starch content is greater than or equal to 10%, a RS3 type resistant starch melting temperature is greater than or equal to 120 DEG C, an amylose content is greater than or equal to 28%, a peak viscosity is greater than or equal to 2500 cP, and the ingredient table only contains corn flour. The low-GI corn flour of the application significantly reduces the glycemic index while retaining the unique processing performance and natural color of corn flour, and is suitable for making sugar-controlled corn cakes, corn paste, meal replacement powder, baking premix powder and other products.

Description

Technical Field

[0001] This invention belongs to the field of food technology, specifically relating to a corn flour with a low glycemic index obtained through a purely physical annealing process. Background Technology

[0002] Corn is one of the world's three major staple foods, and corn flour is the core ingredient in making corn tortillas, corn porridge, meal replacement powders, baking mixes, and other foods. Traditional corn flour typically has a glycemic index (GI) between 70 and 80, classifying it as a high-GI food. For consumers who need to control their post-meal blood sugar, corn flour products are a common source of carbohydrates in their daily diet, highlighting the conflict between their high GI characteristics and the need for blood sugar control. In existing technologies, methods for reducing the GI value of corn flour mainly include adding exogenous ingredients such as dietary fiber and resistant starch. While these methods can lower the GI value of the product, the added exogenous ingredients alter the natural taste and processing properties of the corn flour, and the added ingredients must be listed on the ingredient list, which does not meet clean labeling requirements. The applicant's prior patent application disclosed a method for low-glycemic index physical modification of ordinary corn flour. This method involves generating RS3-type resistant starch in situ within the corn flour granules through an annealing process, reducing the glycemic index (GI) of the corn flour without adding any exogenous components. The resulting product has a GI value ≤60 and an RS3-type resistant starch content ≥8%. This invention, based on this prior process, optimizes annealing parameters to obtain a high-end product with a GI value meeting the stringent low-GI standard (≤55) set by the Codex Alimentarius Commission. The RS3-type resistant starch content is increased to ≥10%, while fully preserving the natural processing properties and color of the corn flour. This invention defines for the first time a low-GI corn flour product with stringent low-GI characteristics and comprehensively defines its quality using six quantitative indicators: GI value, RS3 content, RS3 melting temperature, amylose content, peak viscosity, and color difference. Summary of the Invention

[0003] Purpose of the invention This invention provides a corn flour product with a strictly low glycemic index, produced through a purely physical annealing process, and its quality is fully defined by six quantitative indicators. Technical solution This product uses ordinary corn as raw material and is prepared using a purely physical annealing process. During annealing, amylose molecules rearrange themselves in an orderly manner along the surface of residual microcrystals to form high-melting-point RS3-type resistant starch, reducing the product's GI value. The resulting product simultaneously meets the following requirements: GI value ≤ 55, RS3-type resistant starch content ≥ 10%, RS3-type resistant starch melting temperature ≥ 120℃, amylose content ≥ 28%, peak viscosity ≥ 2500 cP, and the ingredient list contains only corn flour. The color difference value ΔE ≤ 3, and the natural color is not significantly different from untreated corn flour. Core Mechanism The amylose content in corn flour is a key indicator determining the potential for RS3 formation—the higher the amylose content, the more amylose molecules can participate in ordered rearrangement after annealing, resulting in a greater amount of RS3 formation. Annealed RS3-type resistant starch crystals have a complete structure and a melting temperature ≥120℃, remaining stable during subsequent processing and use. Peak viscosity is a core gelatinization indicator for evaluating the processing performance of corn flour—the higher the peak viscosity, the better the thickening ability and gelatinization transparency of the corn flour in cooking. A color difference value ΔE≤3 quantifies the effect of annealing on protecting the natural color of corn flour. Beneficial effects (1) A complete quality index system for low-GI corn flour products has been defined for the first time—ensuring strict low-GI characteristics through GI value and RS3 content, ensuring rapid cooling and crystal locking effect through RS3 melting temperature, ensuring processing performance through amylose content and peak viscosity, and ensuring natural color protection through color difference value. (2) The ingredient list contains only corn flour, with pure physical additives and zero additions, meeting the requirements for clean labeling. (3) Suitable for making sugar-controlled corn cakes, corn paste, meal replacement powder, baking premixes, and other products. Detailed Implementation

[0004] Example 1 Ordinary corn flour was annealed using a purely physical annealing process. The resulting product had a GI value of 52, an RS3 resistant starch content of 11.5%, an RS3 melting temperature of 125℃, an amylose content of 29%, a peak viscosity of 2700 cP, and a color difference ΔE of 2.5. The ingredient list contained only corn flour. When the product was made into corn tortillas, the taste was not significantly different from that of ordinary corn flour tortillas. Comparative Example 1 (using basic process standard parameters, but with downgraded indicators) The annealing parameters were set according to the standard parameters of the basic process. The resulting product had a GI value of 58 (>55) and an RS3 resistant starch content of 8.5% (<10%), which did not meet the high-end product standard of this invention. This proves that the product indicators of this invention can only be achieved by further optimizing the parameters based on the basic process, resulting in an upgraded product. Comparative Example 2 (Addition of exogenous resistant starch to lower GI, ingredient list is not clean) Using untreated regular corn flour with 15% exogenous addition of commercial resistant starch reduced the GI value to 55, but the ingredient list still required the resistant starch to be listed, resulting in a harder texture for the tortillas. This demonstrates that exogenous addition methods cannot simultaneously meet the requirements of clean labeling, low GI, and good taste. Industrial applications This product is suitable for the production of sugar-controlled corn tortillas, sugar-controlled corn paste, meal replacement powders, baking premixes, and other similar products. Six key indicators—GI value, RS3 content, RS3 melting temperature, amylose content, peak viscosity, and color difference—must be included in the product's factory inspection standards. The ingredient list contains only corn flour and complies with clean label requirements.

Claims

1. A low glycemic index corn flour, characterized in that, The corn flour simultaneously satisfies the following characteristics: GI Value ≤55, RS3 resistant starch content ≥10%, RS3 resistant starch melting temperature ≥120℃, amylose content ≥28%, peak viscosity ≥2500cP, and the ingredient list contains only corn flour.

2. The low glycemic index corn flour according to claim 1, characterized in that, The GI value is ≤52, the RS3 resistant starch content is ≥12%, the amylose content is ≥30%, and the peak viscosity is ≥2800 cP.

3. The low glycemic index corn flour according to claim 1, characterized in that, The color difference value of the corn flour is ΔE≤3, and the natural color is not significantly different from that of untreated corn flour.

4. The use of the low glycemic index corn flour according to any one of claims 1-3 in the preparation of sugar-controlled corn cakes, sugar-controlled corn paste, meal replacement powder, and baking premix powder.