Tunable v-type starch matrix for extrusion-stable beet red pigment

Overview

Beet red is an attractive natural color source, but its color molecules are sensitive to heat, shear, and moisture during extrusion processing. This technology uses a tunable V-type starch matrix to shelter beet red pigments under processing conditions.

The matrix is made from food-grade high-amylose starch that is jet-cooked and then annealed with ethanol-water mixtures under controlled conditions. These steps create ordered starch structures with varying levels of V-type organization. Beet color molecules are loaded onto or into the matrix at reduced temperatures, low pH, and limited oxygen, forming a more protective pigment carrier for extrusion and storage.

The intended application is processed food manufacturing, especially extruded snacks, cereals, and other products that require a stable natural red color. The value proposition is not just a carrier but a systematic, evidence-based approach: the technology compares ordered starch carriers against native starch, unannealed starch, empty V-starch, and free color controls, so the benefit of matrix ordering is clearly separated from simple dilution.

Technical specifications

The development program is designed around a staged screen that avoids unnecessarily complex factorial testing.

Matrix preparation:

• Food-grade jet cooking creates a uniform starch base.
• Ethanol-water annealing at 20%, 40%, or 60% ethanol and 50°C, 70°C, or 90°C produces two to three structurally distinct high-amylose matrices.
• Rapid XRD and DSC measurements, along with size and dispersion checks, select the best matrix candidates.

**Characteristics:

• Betanin association is tested at pH 4, temperatures of 25°C or below, and low-oxygen conditions to minimize degradation.
• Payload capacity, color strength, and recovery after drying are measured using HPLC, UV-visible spectroscopy, confocal microscopy, and Raman mapping.
• V-type starch may protect pigments through cavity or non-cavity interactions, including interhelical or amorphous domains. The screens are designed to test both possibilities.

Extrusion validity:

• Promising candidates are advanced through measured resolution, viscosity, payload, and cost-in-use gates.
• Extrusion trials sweep temperatures from 75°C to 150°C with controlled moisture, residence time, and specific mechanical energy.
• Outputs include CIELAB color measurements, pigment recovery, product expansion, density, texture, sensory characteristics, and water activity.

Storage stability:

• Environmental and accelerated tests run for 12 months at ambient and 35–40°C conditions.
• Betanin, isobetanin, and degradation products are tracked to determine long-term color performance.

Technology readiness level

The proposed technology is at an active research and proof-of-concept stage. It does not yet claim commercial delivery and currently best positions as early-stage, with risk-reduction phases designed to produce either a pilot-ready formulation/process window or an evidence-based no-go.

The methodology builds on prior research showing that annealing can tune V-type starch organization and protect pigment microenvironments. This current work extends that platform to the more challenging its-binding molecule, betanin, and focuses on validation under real extrusion and shelf-life conditions.