Designing Spoonable Milk Kefir Gels: From Fermentation Optimization to Clean-Label Gel Structuring with Psyllium

Area of Science:

• Food Science and Technology
• Dairy Science
• Fermentation Technology

Background:

• Kefir, a fermented dairy product, offers nutritional benefits but can be improved texturally.
• Developing spoonable kefir gels requires optimizing fermentation and structuring agents.

Purpose of the Study:

• To develop spoonable milk kefir gels by optimizing fermentation conditions.
• To incorporate psyllium and calcium chloride as clean-label structuring agents.
• To enhance the nutritional and sensory profile of kefir.

Main Methods:

• Comparative analysis of whole and skimmed milk fermentation using a full factorial design.
• Evaluation of inoculum level, temperature, and fermentation time on acidification kinetics (pH, total acidity).
• Rheological characterization of kefir gels with varying psyllium and calcium chloride concentrations.

Main Results:

• Skimmed milk showed accelerated acidification, reaching pH 4.08 and 9.99 g·L^-1 acidity under optimized conditions (5.5% grains, 26 °C, 24 h).
• Psyllium significantly strengthened the gel network, increasing elastic modulus to 209.6 Pa at 3.06% w:w.
• High psyllium content substantially increased zero-shear viscosity (>1500 Pa·s), improving textural properties.

Conclusions:

• Optimized fermentation and clean-label structuring agents (psyllium, calcium chloride) enable low-fat kefir gel development.
• Enhanced textural and processing properties support kefir gels as synbiotic, functional dairy products.
• This approach offers a pathway to novel, improved kefir-based food products.