Development of hydrocolloid microgels as starch granule mimetics: Hydrogel particles fabricated from gelatin and pectin

• Hydrogels were formed by electrostatic complexation of gelatin and pectin.
• The hydrogels were cross-linked by different levels of glutaraldehyde.
• Cross-linking increased the rigidity and melting temperature of hydrogel pastes.
• These hydrogel particles may be used as starch mimetics or delivery systems.

In this study, hydrocolloid microgels fabricated by electrostatic complexation of gelatin and pectin were developed as possible starch mimetics. The impact of covalent cross-linking on the physicochemical and structural properties of the microgels was investigated. Microgels were formed by acidifying a mixture of gelatin (0.5 wt.%) and pectin (0.01 wt.%) from pH 10 to 5 at 40 °C, followed by cross-linking with glutaraldehyde (0 to 2 mM). At low glutaraldehyde levels (< 0.5 mM), cross-linking occurred primarily within the microgels and did not affect particle dimensions, whereas at high levels (2 mM), cross-linking connected adjacent microgels leading to the formation of large flocs. Rheological and microscopic analysis showed that the degree of cross-linking impacted the thermal transitions of the microgels. A simulated oral processing study indicated that the melt-in-the-mouth behavior of the hydrocolloid microgels could be made to be similar to that of starch granules by controlling the degree of cross-linking. This study may be useful for designing starch mimetics with improved texture-modifying properties and reduced-calories.