Kinetic study of the microwave‐induced thermal degradation of cv. Arbequina olive oils flavored with lemon verbena essential oil

Abstract

The effect of typical domestic microwave heating (0–15 min, at 800 W) on the thermal degradation of unflavored and flavored olive oils' minor bioactive compounds and related antioxidant activity was studied. Olive oils from cv. Arbequina were flavored with lemon verbena essential oil (0%, 0.2% and 0.4%, w/w) leading to a linear increase of total phenols (112–160 mg gallic acid kg−1 oil, R‐Pearson = +0.9870), total carotenoids (2.19–2.56 mg lutein kg−1 oil, R‐Pearson = +0.9611), and, to a less extent, of chlorophyll (2.32–3.19 mg pheophytin kg−1 oil, R‐Pearson = +0.8238). However, no such linear trend was observed for the oxidative stability (6.5–7.8 h) or the radical scavenging activity (inhibition rates: 40%–43%). The contents of total phenols, total carotenoids, and chlorophyll decreased with the rise of the microwave heating time, following their thermal degradation, a second‐order kinetic model (0.8784 ≤ R‐Pearson ≤ 0.9926). The essential oil addition did not influence the estimated second‐order rate reaction constants of total phenols (0.00070–0.00072 kg oil min−1 mg−1 gallic acid)and total carotenoids (0.14–0.17 kg oil min−1 mg−1 lutein), with a broader variation observed for chlorophyll (0.014–0.022 kg oil min−1 mg−1 pheophytin). Globally, total carotenoids degraded faster than total phenols and chlorophyll (half‐life of 2.3–3.4, 8.8–12.8, and 14.5–30.8 min, respectively). Moreover, except for chlorophyll, the half‐life of total phenols and carotenoids linearly decreased with the essential oil addition (R‐Pearson: −0.9999 and −0.9421, respectively), showing that flavoring did not have a protective effect against degradation when subjected to a microwave heating.

Monovarietal olive oils fortified with carotenoids: Physicochemical and sensory trends and taste sensor evaluation

“…As can be inferred from the lutein and β‐carotene data listed in Table 1, the success of the fortification was confirmed by HPLC, being found mean contents of 0.084 ± 0.003 mg lutein/ml and 0.109 ± 0.003 mg β‐carotene/ml for the fortified oils, in well accordance with the desired level (0.1 mg/ml). These levels contrasted with the low total contents of both carotenoids found in the unfortified oils (0.001 and 0.007 mg/ml, corresponding to 1.1–4.8 mg lutein/kg oil and 0–2.8 mg β‐carotene/kg oil) in agreement with the literature data (Cherif et al, 2021; Marx et al, 2022).…”

“…Subsequently, 0.3 μl of sodium carbonate solution (20% w/v) were added, and the solution was vortexed and put in darkness at room temperature, letting it react for 60 min. The samples were evaluated in a spectrophotometer (UV/VIS‐1280 Shimadzu) at 765 nm, and the TPC was reported as mg of gallic acid per kg of oil (mg GAE/kg), being used a calibration curve of gallic acid in methanol solution (Cherif et al, 2021).…”

“…Thus, it could be established that, from a practical point of view, fortification slightly decreased the phenolic content but, in general, did not alter the oils' commercial quality grade. Moreover, fortification improved the nutritional value of the monovarietal oils by unclearly increase (Table 1) the usual low content of carotenoids (Cherif et al, 2021;Lim on et al, 2015;Marx et al, 2022), contributing to the fulfillment of the recommended carotenoids daily intake, through the oils' usual consumption. It should be remarked that the physicochemical data and observed trends related with the carotenoids' fortification (Table 1) are, in general, in accordance with the trends previously reported in the literature (Murillo-Cruz et al, 2022;Murillo-Cruz, García-Ruíz, et al, 2021).…”

Bay Laurel (Laurus nobilis L.) Essential Oil as a Food Preservative Source: Chemistry, Quality Control, Activity Assessment, and Applications to Olive Industry Products

“…The major restriction is related to the careful choice of the quantities of the added EO or mixtures of EOs so that the end product exerts balanced sensorial characteristics. Bay laurel EO is rarely reported as a flavoring agent of olive oil [ 140 ], in contrast to the frequent use of other EOs from the Mediterranean flora [ 137 , 140 , 141 , 142 , 143 , 144 , 145 ]. Its addition in olive oil by 0.05% ( v/w ) was found to be promising as far as it concerns 1,8-cineol stability during the thermal oxidation process and under photo-oxidation conditions.…”

Compostos bioativos presentes no azeite de oliva e seus subprodutos: revisão bibliográfica

“…Dentre os diversos processos tecnológicos pode-se citar: uso de microondas (Cherif, Rodrigues, et al, 2021), gel de emulsão (Alongi, et al, 2022;Muñoz-González, et al, 2021), armazenamento em shotgun lipidomics (Capriotti et al, 2021), armazenamento reduzido (BELTRAN et al, 2021, sensor analítico ecológico (Jebril et al, 2021), ultrassom (Del Coco et al, 2021, casca da cebola amarela como estabilizador (CRNIVEC et al, 2021), caracterização sensorial pelo método CATA (Melo et al, 2021), cromatografia (Marx et al, 2021), temperatura adequada de malaxação (Marx et al, 2021;Olmo-Cunillera et al, 2021), encapsulação (Tirado, et al, 2021;Vehapi, et al, 2020;Yao et al, 2021), acréscimo de especiaria , métodos de informática para prever alvos moleculares (Fatoki, et al, 2021), membranas de emulsão a base de líquido iônico (Khan et al, 2021).…”