Effects of filtration process on the minor constituents and oxidative stability of virgin olive oil during 24 months storage time

Abstract

In this study, effects of filtration and storage time on the chemical composition and sensory profile of the virgin olive oil extracted from a local olive cultivar known as Saurani grown in Hatay province of Turkey were determined. Before storing both filtered (F) and unfiltered (UF) samples were categorized as virgin olive oil (VOO) according to the International Olive Council (IOC) standards. The main characteristics of Saurani olive oils were: a mid-oleic acid (69.3%), low linoleic acid (7.7%) and high linolenic (0.85%) acid contents with high total phenolic content (522.34 ppm as gallic acid). Monitoring of stored samples for 24 months revealed significant differences between F and UF olive oils in terms of free acidity and peroxide values, and filtered oils appeared to be better protected against hydrolysis and oxidative deterioration. Free fatty acidity of F and UF olive oil samples which were initially 0.4% and reached to 0.9% after 23 and 11 months’ storage respectively. Peroxide values of the F and UF olive oil samples were exceeded the limit of IOC standard (20 mEq oxygen/kg oil) after ten and three months, respectively. Total phenol contents were higher in UF samples and their contents decreased with storing. Luteolin was the most abundant phenolic compound and tyrosol contents of both F and UF samples reached maximum values in the ninth month of storage. It seemed filtration had no detectable effect on tocopherols contents and about 50% of α-tocopherol destroyed after 24 months’ storage.

Effect of Filtration Process on Oxidative Stability and Minor Compounds of the Cold-Pressed Hempseed Oil during Storage

“…Conflicting conclusions on the influence of filtration and storage on the oxidative stability of the oil can be drawn from the literature. A study from Shendi and coworkers [ 53 ] was consistent with our findings since PV, K 232 , and K 268 significantly differed in filtered and non-filtered olive oils during two years of storage in amber glass bottles, with the highest values observed in non-filtered oil samples at the early months of storage. Liang and colleagues [ 23 ] did not employ filtration but ultrasonic bleaching to reduce the amount of prooxidant components in the hempseed oil, and they found that such a treatment had an impact on the oxidative oil stability as it significantly delayed the increase both in PV and conjugated diene systems, compared to untreated control oils during accelerated storage in colored glass containers.…”

“…Some studies confirmed the progressive decrease in polyphenols during the storage of virgin olive oils. However, higher deterioration rates were recorded in filtered oils than in non-filtered oils, which consequently showed higher total phenol contents [ 53 , 54 ]. Conversely, other research highlighted minimal or no differences in total phenols between filtered and non-filtered olive oils during storage [ 56 , 57 , 58 ].…”

Characterization of ‘Olivastro di Bucchianico cv’ extra virgin olive oils and its recognition by HS‐GC‐IMS

“…[43][44][45] The total phenols content was medium (306 mg kg −1 ). 46,47 In Fig. 1 the sensory profile of 'Olivastro di Bucchianico' is reported.…”

Influence of Malaxation Conditions on Phenolic Composition of Virgin Olive Oils: A Brief Review

“…Moreover, filtration is an important step to remove suspended solids and moisture. The filtration process is recommended due to the moisture reduction improves the oils' quality [55].…”