Effect of olive leaf incorporation during the industrial extraction of cv. Arbequina Olive oils on their quality and bioactive composition
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abstract
Extra virgin olive oil (EVOO) is a key element of the Mediterranean diet and is highly appreciated due to its unique nutritional and organoleptic attributes. The documented health-promoting
properties of EVOO are associated with several chemical families, with a particular relevance to the phenolic composition, namely to phenolic alcohols and secoiridoid derivatives. This fact has been recognized by the European Food Safety Authority leading to a health claim regarding the protective effect of polyphenols from olive oils against the oxidative stress of blood lipids. In this sense, olive oil industry seeks to uncover technological processes that would ensure increasing the phenolic content of olive oils and thus, to fulfill the health claim requirements. Therefore, this study focused on evaluating the effect of cv. Arbequina leaves addition (1%, w/w) during the industrial extraction of cv.
Arbequina oils on their physicochemical-sensory quality, chlorophyll and carotenoids total contents, CIELAB color intensities and individual phenolic profile. It was observed that, leaves incorporation reduced the primary oxidation (peroxide value by 33% and K232 by 17%) and increased the oxidative stability (19%). Moreover, oils amendment promoted the rise of the total phenolic content (up to 293±9 mg GAE/kg), which became richer in secoiridoid derivatives (up to 144±3.0 mg/kg), namely on oleacein content (up to 55±2 mg/kg), as well as in total carotenoids (up to 2.85±0.04 mg lutein equivalents/kg). Furthermore, the addition of Arbequina leaves was able to increase the contents of
secoiridoid derivatives after acid hydrolysis, in comparison with oils extracted without leaves, allowing supporting the health claim (5.2±0.2 mg/20 g). Regarding the sensory attributes, the leaves incorporation during extraction enhanced the bitterness (2.9±0.5) and sweetness (7.0±0.4) but decreased the pungency (1.6±0.4). Although the cv. Arbequina leaf incorporation during oils’ extraction increased the potential positive health impact, oils extracted from olives and leaves should not the commercialized as EVOO, according to the European Union regulations.
