Variations of phenolic compounds and sensory properties of virgin olive oils from the variety 'Istrska belica'

Abstract

The olive variety 'Istrska belica' is well known for its numerous positive properties, such as resistance to low temperature and high oil content. The aim was to determine the variations in the levels of phenolic compounds and sensory properties during storage of 'Istrska belica' virgin olive oil. The profile of the phenolic compounds and sensory properties of 'Istrska belica' olive oil were further compared with those for other varieties, including 'Leccino' and 'Maurino'. The content of phenolic compounds of the olive oils decreased after 1 year and 2 years of storage. After 2 years of storage, the levels of oleuropein and the ligstroside derivates significantly decreased, while the end-stage compounds tyrosol and hydroxytyrosol increased. These data show that after 1 year of storage, the 'Istrska belica' olive oil preserves similar intensities for bitterness and pungency, and similar oleuropein and ligstroside derivates levels. In contrast to the other oils analysed, the intensities of bitterness and pungency of 'Istrska belica' olive oil decreased greatly only after 2 years of storage. Moreover, the phenolic compounds content, and oleuropein and ligstroside derivates levels, and the intensities of bitterness and pungency were the highest in fresh 'Istrska belica' olive oil, compared to the other olive oils analysed. Overall, 'Istrska belica' olive oil has important advantages over olive oil from other varieties that are grown in the Istria region.

Oleocanthal Quantification Using 1H NMR Spectroscopy and Polyphenols HPLC Analysis of Olive Oil from the Bianchera/Belica Cultivar

“…As it can be seen from Table 6 , all olive oils of the Bianchera cultivar (samples 1 to 6) had a TPC higher than 5 mg/20 g, while for the other cultivars, only two had a good value (samples 7 and 9). This was in accordance with what is already presented in the literature [ 40 , 41 , 42 ].…”

Developing an Olive Biorefinery in Slovenia: Analysis of Phenolic Compounds Found in Olive Mill Pomace and Wastewater

“…All results are expressed as mg/kg dry weight (dry wt) of pomace sample. Although from the literature it is well known that the phenolic compound concentrations are affected by agronomic and technological factors, including the cultivar type, ripening stage and geographic origin [6,31], the total amount of phenolic compounds that varied from 851 mg/kg dry wt to 4473 mg/kg dry wt (Table 1) are in the range previously reported elsewhere [14,31]. Podgornik et al [14], with the same extraction and detection method, determined that the total phenolic compounds range from 500 to 8000 mg/kg d.w.…”

“…These simple phenolic compounds may be the primary products from the oxidative decomposition of secoiridoids [44,45]. In our previous study [6], it was determined that an increase in tyrosol and hydroxytyrosol and decrease in secoiridoids levels resulted after one and two years of storage for extra virgin olive oil samples.…”

“…At the heart of this is the "Istrska belica" cultivar of olives (Istrian white olives), which have been praised for their ability to withstand low temperatures during cultivation, maximizing oil content and possessing an excellent taste. This cultivar has high levels of monounsaturated fatty acids and biologically active molecules, including phenolic compounds, squalene and tocopherols [2][3][4][5], in comparison to other Slovenian Istria varities, which contribute to the organoleptic profile of the oil produced from these olives [6]. Phenolic compounds from olives may offer a variety of benefits to human health, including a reduction in coronary heart disease risk factors, prevention of several types of cancers and modification of immune and inflammatory responses [7][8][9].…”

“…During the olive oil manufacturing process, ligstroside and oleuropein can enter different transformation-reaction pathways involving plant enzymatic and chemical transformation [22]. When the transformation pathway reaches its end and the olive oil has already lost its freshness and antioxidative properties after one or two years of storage, the total phenolic compounds content can be relatively high with higher amounts of simple phenolic compounds such as tyrosol and hydroxytyrosol [6]. The same process of complex phenolic compounds breaking down into simple phenolic compounds, such as tyrosol and hydroxytyrosol, is expected to occur in olive mill effluents over relatively short periods of time.…”