ORIGINAL ARTICLE Phenolic Profile and Thermal Stability of Monovarietal Extra Virgin Olive Oils Based on Synchronous Fluorescence Spectroscopy Hina Ali 1 & Muhammad Azhar Iqbal 2 & Babar Manzoor Atta 1 & Rahat Ullah 1 & Muhammad Bilal Khan 1 Received: 9 October 2019 /Accepted: 13 April 2020 # Springer Science+Business Media, LLC, part of Springer Nature 2020 Abstract The olive oil production in Pakistan has recently been started with the cultivation of exotic cultivars that are successfully adapted at Barani Agriculture Research center (BARI), Chakwal, Pakistan in Potohar valley. Therefore, characterization of extra virgin olive oil (EVOO) from this agro-climatic region is mandatory in establishing its biochemical profile and thermal stability. Seventeen monovarietal EVOOs extracted from these cultivars were analysed using synchronous fluorescence spectroscopy (SFS) and subjected to heating at 115, 150 and 170 °C for 15 min to identify their thermal stability. SFS emission spectra differentiated EVOOs on the basis of phenolic compounds that are denatured at high temperature, further chlorophyll contents also decreased with increasing temperature. The strong emission at ca. 351 nm, suggested to be vanillic acid, 391–471 nm for blue green region (BGR) assigned to other phenolic compounds and two peaks at 672 and 723 nm for chlorophyll became the bases for grouping through Hierarchical clustering. Most of the EVOOs were stable at 150 °C but showed denatured spectra at 170 °C, the only EVOO extracted from Spanish cultivar Arbequina was found to have moderate fluorescence emission from both vanillic acid and BGR that are more likely to impart oxidative stability even after heating at 170 °C, also confirmed by lowest values of specific extinction co-efficient (K 232 and K 270 ). Moreover, variation in phenolic contents of Arbequina EVOO was observed with different harvesting stages and the early harvested olives produced more thermally stable oil as compared to late harvested olives. Arbequina oil grown in Pakistan can be better suited for cooking at high temperatures, moreover can be blended with other monovarietal EVOOs to enhance the nutritional benefits and thermal stability. Keywords Monovarietal EVOO . Heating . Olive cultivars . Phenolic compounds . Ferulic acid . Blue green region . Chlorophyll Introduction Extra virgin olive oil (EVOO) is the non-chemical extraction; basically cold pressing of freshly harvested olives, is unique for its taste, chemical composition and production method. The health benefits of this Mediterranean diet have been known for sometimes and are getting importance as people are aware of healthy life style. Extra virgin olive oil helps in regulating cholesterol level and keeps the heart healthy mainly due to the presence of monounsaturated fat contents. Besides fatty acids as a major component of EVOO, minor compo- nents comprise of phenolic compounds, tocopherols, chloro- phyll and other pigments [1]. These health promoting micro constituents present in EVOO help in inhibition of oxidation by scavenging reactive oxygen species and metal chelation in cell culture and in vivo [2, 3]. The olive oil production is influenced by soil condition, climate and agricultural practices. There are thousands of dif- ferent varieties of olive that differ in fruit size, oil quality, taste and chemical composition [4]. Each variety has characteristic concentration of phenolic compounds that owe to its pedoclimatic conditions, extraction process and storage etc. [5]. Phenolic contents of a cultivar also depend upon degree of fruit ripening, storage of fruit prior to oil extraction, harvest practices and geographical conditions [6]. Normally different olive varieties are mixed by farmers for the extraction of olive oil. Construction of mills in private sector made it convenient Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10895-020-02538-7) contains supplementary material, which is available to authorized users. * Hina Ali hinali991@hotmail.com 1 National Institute of Lasers and Optronics (NILOP), Lehtrar Road, Islamabad, Pakistan 2 Barani Agricultural research Institute (BARI), Chakwal, Pakistan Journal of Fluorescence https://doi.org/10.1007/s10895-020-02538-7