Enrichment of table olives with polyphenols extracted from olive leaves (original) (raw)

The effects of processing methods on polyphenol content of some Turkish black table olives

2021

LA RIVISTA ITALIANA DELLE SOSTANZE GRASSE VOL XCVIII LUGLIO/SETTEMBRE 2021 LA RIVISTA ITALIANA DELLE SOSTANZE GRASSE VOL XCVIII LUGLIO/SETTEMBRE 021 In this study, Gemlik, Memecik and Uslu olive varieties, which are important for the Turkish black table olive sector, were analysed to determine the effects of processing methods on the types and amounts of the polyphenols which have potentially high antioxidant activities. The effects of the processing techniques on the phenolic compounds were found statistically significant in the level of p<0.01. It was determined that the number of phenolic compounds decreased due to the diffusion into brine especially in the processing of ripe olives. In particular, the application of caustic to remove the bitterness of the olive and the darkening of the olive through oxidation applied in the California type processing caused the hydrolysis of polyphenols and increased diffusion. However, the production techniques applied for natural black oliv...

A Study on the Enrichment of Olive Oil with Natural Olive Fruit Polyphenols

International Journal of Food and Biosystems Engineering, 2017

In the last years, has been a sudden and increased interest by scientists in producing creating plant origin food products. This is explained by their polyphenolic content, to which has been attributed a large scale bioactivity as described in many studies. Foods that have beneficial effects due to their high content in polyphenols are olive oil, wine, cocoa, coffee, fruits and vegetables with intense color, whole grain products, tea and other herbal beverages. The purpose of this study was the enrichment of olive oil with olive polyphenols and specifically with hydroxytyrosol, tyrosol, and oleuropein aglycones in order to produce a final product with increased bioactivity and official health claim. Initially, we developed a fast and accurate method of total polyphenols analysis by UV-VIS method, in order to evaluate the degree of enrichment of olive oils, by three specific chosen methods. Also, the UV-VIS method was used to examine and to measure the commercial olive polyphenols compared with cold pressed olive oil. The three alternative oil enrichment methods with olive polyphenols are: I) Addition of encapsulated polyphenol derivatives into liposomes, II) Extraction of polyphenols from olive oil using an organic solvent and then incorporating them with cryogenics sublimation with another olive oil, III) Extraction of polyphenols in the body olive oil from olive leaves using ultrasound at a controlled low temperature. Consequently, based on the results, the first two methods are effective. The final product combines nutritional and medical benefits in the prevention of diseases and can be used by the industry, for food and pharmaceutical products improvement.

Solvent Extraction and Chromatographic Determination of Polyphenols in Olive Pomace

2017

Olive oil mill waste obtained after two-phase olive oil extraction process was subjected to conventional liquid solvent extraction under different pH/temperature/duration conditions using different types of food-grade solvents. The independent variables were: solvent type (ethanol percentage), extraction temperature (20-90 °C), extraction time (30 min-24 h) and pH (210.3) of extraction solvent while the response variables were total phenolic content and antioxidant activity of obtained extracts. The optimum solvent extraction conditions for phenols were 120 min at 70 °C using 60% ethanol as extraction solvent, at solvent to sample ratio 5:1 (v/w). For quantification of major bioactive olive polyphenols hydroxytyrosol, tyrosol and oleuropein in obtained extracts, fast and simple RP-HPLC-DAD method was developed and validated. Oleuropein was presented in highest amounts with average value of 115.14±0.19 mg/kg of fresh olive pomace.

Effect of Pretreatment of Olive Leaves on Phenolic Content and Antioxidant Activity

Background: Recent studies suggest that olive leaves are a significant source of bioactive phenolic compounds comparable to olive oil and fruits. Identifying pretreatment before extraction such as solar dried, oven dried and blanched is thus essential to increase the level of such bioactive components in olive leaves, which is considered an agricultural waste. One of these treatments was blanching on 90-95EC for 20 sec. Objective: So, the aim of the present study was undertaken in order to investigate the impact of appropriate treatment before drying and extraction on the total phenolic compounds quantity and antioxidant activity in olive leaves. Methodology: Olive leaves samples were divided into four parts, Fresh Leaves (FL), Solar Dried Leaves (SDL) and Oven Dried Leaves (ODL) and Blanched Dried Leaves (BDL) on (90-95EC) (1:4 w/v) for 20 sec. Total phenolic content, flavonoids and antioxidant activity of different treatments of olive leaves were estimated. Results: The blanching of olive leaves for 20 sec increased up to 593.00 μg GAE gG1 (61.70%). A linear relationship was observed between the potential antioxidant activity, total phenolic and flavonoid levels of the olive leaves extract. These results emphasized that olive leaves were contained significant amounts of phenolic content and flavonoids which crucial for their antioxidant capacity. Ethanol extract of the blanched-dried leaves showed the highest antioxidant activity (IC50 = 149.92 μg mLG1) compared to methanol and water extract. Conclusion: In the present study, it can conclude that the bunching of olive leaves may improve the level of phenolic content and flavonoids and consequently antioxidant capacity has been enhanced.