Drying of Australian native herbs lemon myrtle (Backhousia citriodora) and lemon-scented tea tree (Leptospermum petersonii), extraction and encapsulation of polyphenols from these dried herbs

The Australian native plants lemon myrtle (LM) (Backhousia citriodora) and lemon-scented tea tree (LSTT) (Leptospermum petersonii) are well known for their lemon aroma. Their leaves have been used in culinary and traditional medicines for centuries. Preliminary studies have found these leaves are rich in polyphenolic compounds which possess strong antimicrobial and antioxidant properties, thus showing great potential for applications in food and nutraceutical products. The stability, extractability, and bioaccessibility of phenolic compounds largely depend on processing conditions, however, there is limited information available on suitable drying, extraction, and encapsulation conditions to retain and maximize extraction yield of phenolic compounds for further applications. Therefore, this project investigated the impact of different drying methods and conditions on the retention of phenolic compounds to identify the most suitable drying technique for the preparation of dried leaves, examined the effects of major extraction conditions using conventional and novel techniques to determine the most suitable conditions for obtaining the phenolic rich extracts from dried leaves. Further to this, it is intended to evaluate the influence of encapsulation conditions on properties and stability of the phenolic enriched extracts to prepare the stable encapsulated extracts for further applications.