Olives affected by active and damaging infestation (olive fruit fly
(Rossi)) were assayed for their chemical composition. Biophenols were determined by HPLC, sterols, triterpenic dialcohols, and ...fatty acids by gas chromatography analysis. The acquired data were statistically analyzed. Oils produced from "Istrska belica" fruit affected by active infestation compared to the oils made from fruit affected by damaging infestation showed higher amounts of total oleuropein biofenols (377.3 versus (vs.) 106.6 mg/kg), total biophenols (755 vs. 377 mg/kg), lignans (85.3 vs. 32.9 mg/kg), the dialdehydic form of decarboxymethyl oleuropein aglycone (DMO-Agl-dA) (148.3 vs. 49.0 mg/kg), its oxidized form (DMO-Agl-dA)ox (35.2 vs. 8.5 mg/kg), the dialdehydic form of oleuropein aglycone (O-Agl-dA) (61.1 vs. 8.0 mg/kg), the dialdehydic form of ligstroside aglycone (L-Agl-dA) (63.5 vs. 28.0 mg/kg), the aldehydic form of oleuropein aglycone (O-Agl-A) (40.6 vs. 8.4 mg/kg), and lower amounts of tyrosol (Tyr) (6.0 vs. 13. 9 mg/kg) and the aldehydic form of ligstroside aglycone (L-Agl-A) (13.8 vs. 40.3 mg/kg). Higher values of stigmasterol (2.99%) and lower values of campesterol (2.25%) were determined in oils affected by damaging infestation; an increase in triterpenic dialcohols was also observed (3.04% for damaging and 1.62% for active infestation). Oils affected by damaging infestation, compared to active infestation, showed lower amounts of oleic acid (73.89 vs. 75.15%) and higher amounts of myristic (0.013 vs. 0.011%), linoleic (7.27 vs. 6.48%), and linolenic (0.74 vs. 0.61%) acids.
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.
The health effects of olive oil are attributed to its high content of oleic acid and other constituents, particularly its phenolic fraction. Olive oil also contains other substances with potential ...health effects such as coenzyme Q10 (CoQ10) and coenzyme Q9 (CoQ9). The objective of our study was to investigate some factors that could influence the quantity of coenzyme Q (CoQ) in olive oils. We analyzed almost 100 samples of commercial oil blends and fresh extra virgin olive oils of various cultivars using high-performance liquid chromatography. With the investigation of various monocultivar samples we determined that genetic parameters (cultivars) have an important influence on the composition of olive oils, particularly the content of CoQ10. Possible effects of the degree of ripeness were also studied for the cultivars Istrska belica and Leccino. We determined that the highest levels of both CoQ10 and CoQ9 can be found in early maturation stages.
Changes in the physico-chemical parameters of extra virgin olive oils after heating for 142h at 100°C with an air flow 10L/h were investigated. The experimental study was carried out on the two ...predominant olive cultivars in Slovenian Istra – cv. Istrska belica and cv. Leccino. The data obtained showed that oils from Istrska belica were more stable than those from Leccino. Peroxide values and spectrophotometric data showed higher amounts of oxidation products in oils from Leccino than in those from Istrska belica. After thermal treatment fatty acid composition was changed more in Leccino oils; particularly the amounts of polyunsaturated fatty acids dropped significantly, while α-tocopherol was completely depleted in all samples. The content of total biophenols decreased from 598mg/kg to 241mg/kg in Istrska belica oils and from 391mg/kg to 176mg/kg in Leccino oils. HPLC data showed that transformation of secoiridoid biophenols to the simple biophenols, tyrosol and hydroxytyrosol took place.
The objective of the research is to determine the leading microorganisms in spontaneous fermentations of table olives in Slovenian Istria. The influence of traditional regional and modified Spanish ...style technology on yeast and lactic acid bacteria population dynamics and on the quality of Istrska belica and Storta table olive varieties was studied during 180 days of fermentation. Apart from that, pH of the brine during fermentation and total biophenols in olive fruits before processing and after 60 and 180 days of fermentation were determined. The quality of the final product was determined with sensory analysis. Table olive fermentation was carried out by yeasts. Aureobasidium pullulans, Cryptococcus adeliensis, Metschnikowia pulcherrima, Rhodotorula mucilaginosa, Pichia anomala and Candida oleophila were isolated and identified using PCR-RFLP analysis of ITS regions and traditional phenotypic tests. High initial amount of total biophenols in olive fruits and their better preservation during traditional processing influenced microbial population dynamics and quality characteristics of table olives. The modified Spanish style technology was not confirmed as suitable for retaining positive characteristics of the product of traditional regional technology in Slovenian Istria. Key words: table olives, Istrska belica, Storta, fermentation, yeasts, total biophenols, sensory characteristics
Svrha je istraživanja bila odrediti glavne mikroorganizme koji sudjeluju u spontanoj fermentaciji stolnih sorata maslina, uzgojenih u slovenskom dijelu Istre. Tijekom 180 dana fermentacije ispitan je ...utjecaj tradicionalnog i modificiranog španjolskog načina prerade na dinamiku populacije kvasaca i mliječno-kiselih bakterija, te na kakvoću stolnih maslina Istrska belica i Storta. Osim toga, mjerena je pH-vrijednost rasola i određeni su ukupni biofenoli u neprerađenim plodovima te u plodovima nakon 60 i 180 dana fermentacije. Senzorskom je analizom ispitana kakvoća stolnih maslina pa je utvrđeno da kvasci prevladavaju tijekom njihove fermentacije. Kombinacijom molekularno-biološke metode, PCR-RFLP analizom ITS područja, i tradicionalne metode identifikacije kvasaca identificirane su ove vrste: Aureobasidium pullulans, Cryptococcus adeliensis, Metschnikowia pulcherrima, Rhodotorula mucilaginosa, Pichia anomala i Candida oleophila. Veliki udio ukupnih biofenola u plodovima prije prerade i u stolnim maslinama, pripravljenim na tradicionalan način, utječe na dinamiku populacije mikroorganizama i kakvoću stolnih maslina. Modificirani španjolski način prerade nije prikladan za očuvanje pozitivnih značajka tradicionalne prerade stolnih maslina, uzgojenih u slovenskom dijelu Istre.
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