Quality of pomegranate pomace as affected by drying method

Area of Science:

• Food Science and Technology
• Agricultural By-product Valorization
• Drying Technologies

Background:

• Pomegranate juice production generates substantial pomace, a valuable co-product.
• Effective drying methods are needed to unlock commercial applications for pomegranate pomace.
• Pomace quality is influenced by drying kinetics and applied temperatures/powers.

Purpose of the Study:

• To evaluate convective drying (CD), vacuum microwave drying (VMD), and a combined convective-vacuum microwave finish drying (CPD-VMFD) method.
• To determine the impact of different drying parameters on pomegranate pomace (PomP) quality.
• To assess the potential of PomP as a source of valuable compounds for industry.

Main Methods:

• Comparative analysis of three drying techniques: CD (50-70°C), VMD (240-480W), and CPD-VMFD (60°C pre-dry + 360W finish-dry).
• Evaluation of drying kinetics, color (a* coordinate), total phenolic content, antioxidant activity, and punicic acid content.
• Analysis of fatty acid profile and sensory attributes (off-flavors).

Main Results:

• VMD at 240W and 360W were the fastest drying methods (52 and 33 min).
• These VMD treatments preserved high levels of total phenolic content and antioxidant activity.
• Pomegranate pomace is rich in punicic acid (average 66.4%), with no significant changes in fatty acid profile or off-flavors observed across drying methods.

Conclusions:

• Vacuum microwave drying is an efficient method for drying pomegranate pomace, preserving its quality.
• The resulting pomace is a valuable source of punicic acid, suitable for pharmaceutical and nutraceutical applications.
• Optimized drying strategies can enhance the commercial viability of pomegranate pomace.