Oxidative Stability of Virgin Avocado Oil Enriched with Avocado Leaves and Olive-Fruit-Processing By-Products (Leaves, Pomace) via Ultrasound-Assisted Maceration  
[PERSON]  
1 Laboratory of Food Chemistry and Technology, School of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; [EMAIL_ADDRESS] (P.J. ); [EMAIL_ADDRESS] (S.S.) 1  
[PERSON]  
1 Laboratory of Food Chemistry and Technology, School of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; [EMAIL_ADDRESS] (P.J. ); [EMAIL_ADDRESS] (S.S.) 1  
[PERSON]  
2 Laboratory of Oncology and alcoholic Beverages, Department of Food Science and Technology, School of Agriculture, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; [EMAIL_ADDRESS] (S.S.) 1  
[PERSON]  
4 Department of Food Science and Technology, Perrotis College, American Farm School, 55102 Thessaloniki, Greece; [EMAIL_ADDRESS] 4  
[PERSON]  
1 Laboratory of Food Chemistry and Technology, School of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; [EMAIL_ADDRESS] (P.J. ); [EMAIL_ADDRESS] (S.S.) 1  
Footnote 1: email: {1,3,4,5,6,7,8,9}  
Footnote 2: email: {1,3,4,5,6,7,8,9}  
Footnote 3: email: {1,3,4,5,6,7,8,9}  
Footnote 4: email: {1,3,4,5,6,7,8,9}  
Footnote 5: email: {1  
+++ ==WARNING: Truncated because of repetitions==
,3,4,5,6,7,8,9}  
++  
polyunsaturated fatty acids. Sterols and other liposoluble bioactive compounds such as \(\alpha\)-tocopherol and carotenoids are also found in virgin, unrefined avocado oil. On the other hand, low-molecular-weight, polar phenolic compounds, known as efficient free-radical scavengers, are usually absent [1]. Several studies support this evidence, although the phenol composition data from chromatographic analyses are rather scarce [2; 3; 4]. The naturally poor content in polar phenols is probably the reason why VAO is highly susceptible to oxidation and displays a rather short shelf-life [2] (e.g., 7.06 h, 110 \({}^{\circ}\)C, 20 L/h). Thus, there is a need to improve the oxidative stability of VAOs while maintaining their functional properties over a longer storage period. Recently, [PERSON] et al. [5] proposed the addition of an extract from an endemic Chilean berry (maqui) by-product (leaves) to improve the thermal stability of the oil. To our knowledge, this is the only report on avocado oil treatment for such a purpose. Nowadays, the sustainability of the avocado oil industry is an issue for both producers and consumers, considering the global distribution channels and the seasonality of the market [6]. In the Mediterranean areas where avocado cultivation was introduced a few decades ago, there is still a gap in knowledge about the optimum oil-processing technologies and quality specifications. Nevertheless, short supply chains are in favor of premium quality products. In addition to that, the circular economy concept that gained popularity over the last few years promotes the idea of reusing local agro-industrial by-products and upcycling by-products as carriers of bioactive constituents or fortification agents of edible oils [1]. Such a trend applies to the production and trade of minimally processed, high-quality VO and CPO products. Avocado tree by-products and residues, e.g., leaves, peels, and seeds, have never been used for this particular purpose despite their potential as sources of antioxidant ingredients [7]. Instead, in a work published a few years ago, avocado and olive-leaf extracts were used to enhance the thermal stability of canola and high-oleic sunflower oils during frying [8]. The authors reported that under thermal oxidation conditions, B-type trimer procyanidins, as the major phenolic compounds in polar avocado leaf extracts, were less effective than oleupopein, the major active constituent of olive-leaf extract; this performance was attributed to well-established structure-activity relationships.