Effect of a Novel Pretreatment Before Freeze-Drying Process on the Antioxidant Activity and Polyphenol Content of Malva sylvestris L., Calendula officinalis L., and Asparagus officinalis L. Infusions

Through the years, the need of reducing waste from the food industry has become a global concern and researchers are trying to understand how to decrease this loss along the supply chain. Officinal plants and vegetables are known to be rich in bioactive metabolites with antioxidant, anti-inflammatory, and anticancer effects. Based on this consideration, in this work, all parts of edible plants (Malva sylvestris L. and Calendula officinalis L.) and all parts of two varieties of asparagus were used to prepare infusions without producing any kind of waste through the application of a patented process. The total polyphenol content (TPC) and antioxidant activity were measured on fresh, dried, and freeze-dried sample powders obtained by non-thermal, solvent-free, non-invasive patented technological process. Infusions from Malva sylvestris L. and Asparagus officinalis L. var. Early California powders showed a higher content of polyphenols than Calendula officinalis L. and Asparagus officinalis L. var. Vegalim. Further analyses are in progress to compare these infusions with commercial ones.