A practical optimization on salt/high-methoxyl pectin interaction to design a stable formulation for Doogh

Area of Science:

• Food Science and Technology
• Fermentation Science
• Rheology

Background:

• Doogh is a traditional Iranian fermented beverage with a long history.
• Maintaining the stability and desired rheological properties of Doogh during production and storage is crucial for commercial viability.
• High methoxyl pectin (HMP) is a potential stabilizer for fermented dairy drinks.

Purpose of the Study:

• To determine the optimal formulation for producing stable Doogh using high methoxyl pectin (HMP) and salt.
• To investigate the effects of HMP and salt concentrations on Doogh's physical and rheological characteristics.
• To compare the optimized Doogh with commercial samples.

Main Methods:

• Response Surface Methodology-Central Composite Design (RSM-CCD) was employed to optimize the formulation.
• The study investigated the impact of HMP (0.28-0.42% wt) and salt (0.4-1.1% wt) concentrations.
• Key parameters analyzed included stability, viscosity, mean droplet diameters (D₄₃ and D₃₂), and Span value.

Main Results:

• The optimal Doogh formulation contained 0.4% wt HMP and 0.62% wt salt.
• Under these conditions, Doogh achieved 96.34% stability, 2.05 mPas viscosity, and desirable droplet size distribution (D₄₃=11.922 μm, D₃₂=0.966 μm, Span=2.140).
• No significant differences were observed in physical, rheological, or sensory attributes compared to commercial Doogh samples.

Conclusions:

• The study successfully identified an optimal formulation for stable Doogh production using HMP and salt.
• The optimized Doogh exhibits comparable quality to commercial products, indicating potential for industrial application.
• RSM-CCD is an effective tool for optimizing the formulation of fermented beverages like Doogh.