L-Proline-Mediated Modulation of Astringency in Black Chokeberry Puree: Molecular Interactions, Process Optimization,...

Area of Science:

• Food Science
• Biochemistry
• Sensory Science

Background:

• Aronia melanocarpa (chokeberry) puree is rich in beneficial anthocyanins and proanthocyanidins.
• High tannin content causes astringency, limiting consumer acceptance of chokeberry products.

Purpose of the Study:

• To develop a non-removal astringency modulation strategy for chokeberry puree using L-proline.
• To investigate the molecular mechanisms, optimal processing conditions, and quality impacts of L-proline treatment.

Main Methods:

• Spectroscopic analyses (UV-Vis, FT-IR) to study molecular interactions.
• Polyphenol-protein precipitation assays using a model system.
• Machine learning-assisted optimization and Box-Behnken validation for processing parameters.
• Sensory evaluation and quality assessments (color, dispersion, vitamin C, anthocyanins).

Main Results:

• L-proline modified the microenvironment of procyanidin B2 (PC-B2) via hydrogen bonding and hydrophobic interactions, without degrading PC-B2.
• L-proline treatment reduced protein precipitation by 30.8% and increased soluble phenolic retention in a model system.
• Optimized conditions (150 mg/100 mL L-proline, 40 °C, 60 min) achieved 36.13% deastringency with high retention of anthocyanins (88.80%) and vitamin C (55.56%).
• The treatment preserved key quality attributes, enhanced anthocyanin bioavailability, and significantly improved sensory acceptance (from 4.17 to 8.17).

Conclusions:

• L-proline mediated microenvironmental modulation offers a mild processing approach to reduce astringency in high-tannin berry products.
• This strategy enhances the acceptance and nutritional value of Aronia melanocarpa puree.
• The findings support L-proline as an effective tool for improving the quality of cloudy berry products.