Effects of sweetener type and storage conditions on physicochemical properties, phenolic compounds, and antioxidant properties of cherry laurel (Prunus laurocerasus) pulp and marmalade

The present research investigated the physicochemical properties, phenolic profile, total phenolic content (TPC), total anthocyanin content (TAC), and antioxidant properties of cherry laurel (Prunus laurocerasus L.) pulp and marmalade (with sucrose and stevia addition) during storage. Pulp and marmalades were stored at room temperature and in the refrigerator and analyzed periodically. It was found that sample type, storage temperature, and time had a statistically significant effect on color parameters (L*, a*, b*, C*, and H degrees). Sample type also significantly affected pH, titratable acidity, total dry matter, ash, reducing sugar, sucrose, total sugar, TPC, TAC, and DPPH antioxidant activity. Storage time affected total dry matter, soluble solids content (SSC), reducing sugar, total sugar, TPC, TAC, and antioxidant activity, whereas storage temperature affected total dry matter, water-soluble dry matter, reducing sugar, total sugar, TPC, TAC, and antioxidant activity. Antioxidant activity, TPC, and TAC decreased with increasing storage time. Samples stored in the refrigerator displayed higher antioxidant activity, TPC, and TAC than those stored at room temperature. Pulp and marmalades contained chlorogenic acid and keracyanin chloride. Principal component analysis (PCA) was conducted to evaluate the impacts of sweetener type, storage time, and temperature. It was determined that sucrose-added marmalade formed a similar group, while pulp and stevia-added marmalade constituted a different group. Finally, this study supported the use of cherry laurel pulp and marmalade as natural sources of antioxidants.