Effect of Hibiscus sabdariffa and Camellia synensis extracts on microbial, antioxidant and sensory properties of ice cream.

Herbal extracts have been widely used by consumers for food fortification and medical purposes worldwide and are focused in traditional medicine in recent years. At this study, we aimed to examine the antimicrobial, antioxidant and sensory characteristics of ice creams fortified with different combinations of Hibiscus sabdariffa and Camellia synensis determined by Design of Experiments software. Levels of 10-100 and 40-400 mg/kg for Hibiscus sabdariffa and Camellia synensis extracts, respectively, were selected and experiments were conducted by central composite design. Generally, 13 runs were introduced by the software and followed in laboratory for analysis. Antimicrobial activity was studied against Escherichia coli and Staphylococcus aureus as indicators of gram negative and gram positive bacteria. Results showed that all combinations were active against both bacteria but Staphylococcus aureus was more sensitive than Escherichia coli. Importantly, Camellia synensis was more effective than Hibiscus sabdariffa in both antimicrobial and antioxidant experiments but sensory panelists selected the sample containing lowest concentrations of both extracts. However, frequent consumption of low-dose fortified dairies with Hibiscus sabdariffa and Camellia synensis could be helpful for consumers interested in functional foods. © Association of Food Scientists & Technologists (India) 2021.