Duncan, Christopher Edward (2012-02). Factors Influencing the Stability and Marketability of a Novel, Phytochemical-Rich Oil from the Acai Palm Fruit (Euterpe oleracea Mart.). Doctoral Dissertation.
Thesis
The acai palm fruit has recently become the focus of numerous research endeavors due to its extraordinary antioxidant content. However, little is known about the fruit's phytochemical rich oil, which is a by-product of the acai pulp. Therefore, the aim of this study was to investigate the phytochemical content of acai oil and its relation to oxidative stability. A total of 206 mg/kg of chlorophylls, which included chlorophyll a as well as four chlorophyll derivatives were tentatively identified by HPLC in crude acai oil (CAO). Two predominant carotenoids (216 mg/kg ?-carotene and 177 mg/kg lutein) were also characterized in addition to ?-tocopherol (645 mg/kg). Initial investigations into oil stability focused upon the photooxidation of acai oil due to its significant chlorophyll content and findings demonstrated that the increases of nonanal were observed when phospholipids and polyphenolics were reduced. Subsequently, investigations into the interactions between phospholipids and lipophilic antioxidants and their contributions to the stability of acai oil were also assessed by isolating phytochemicals and selectively reconstituting the oil. Findings demonstrated a potential relationship between phospholipids and lipophilic antioxidants, but this was not conclusive. Advances in the processing of the acai pulp by-product created from the clarification process yielded a partially refined acai oil (RAO). The stability of both RAO and CAO as a result of autoxidation were compared to other common food oils (olive, canola, and soybean) and primary and secondary oxidation data suggested CAO was most stable. The difference in the stability of the two acai oils was also investigated by blending these oils and assessing oxidation. An increased stability was demonstrated in the blended RAO, which suggested a significant antioxidant contribution from the CAO. With such similar lipophilic compositions in CAO and RAO, it is theorized that the driving factor behind the stability of CAO can be attributed to its water soluble antioxidant content. While further investigations are required to fully comprehend the interactions of acai oil phytochemicals, these experiments provide insight into the phytochemical content and stability of acai oil. The understanding and information obtained in these studies is geared at increasing the marketability of acai oil as a food ingredient.
