Olive oil mixtures. Part two: Detection of soft deodorized oil in extra virgin olive oil through diacylglycerol determination. Relationship with free acidity

Abstract

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Extra virgin olive oil: A comprehensive review of efforts to ensure its authenticity, traceability, and safety

“…Different EVOO components have been proposed as possible markers of fraudulent activities, including natural chlorophyll, diacylglycerols (DAG), FA, wax esters, phenolic compounds, and sterols (Garcia et al., 2013; Gómez‐Coca et al., 2020).…”

“…This methodology, however, requires a pretreatment of the sample to obtain FA methyl esters. Deodorized olive oil in EVOO was successfully detected by the determination of DAGs and free FAs (Gómez‐Coca et al., 2020). A comparative study analyzing TAG by electrospray ionization MS (ESI‐MS) and FA by GC‐FID concluded that the spectroscopic technique was faster and more efficient than the chromatographic method.…”

Pyropheophytin a in Soft Deodorized Olive Oils

“…Actually, such studies use the determination of glyceridic compounds to detect the presence of soft deodorized oils in virgin olive oils. They focus on the fact that, after the application of mild refining conditions, the relationship between the diacylglycerol content and the free acidity breaks [20].…”

“…Following those previous lines of research, we were convinced that the quantities and relations of phy and pyphy could be suitable markers for olive oil processing. Therefore, we decided to study how phy and pyphy were affected by soft deodorization and to establish the relationship between VOO chlorophyll pigment composition and the presence of soft deodorized oils, taking into account that the soft deodorization procedure may be tailored to suit the characteristics of the raw material [20].…”

“…One of the strategies commonly used consists of a neutralization (in case of high free acidity and/or very high bitterness) and/or soft deodorization at a low temperature (in case of low free acidity but negative sensory characteristics), and then blending with extra virgin olive oil (EVOO) [ 15 ]. This practice is difficult to detect since the conventional refining markers, such as stigmastadienes [ 16 , 17 , 18 ], trans fatty acids, ad TAG dimers [ 19 ], are only formed at high temperatures, such as those in standard deodorization in which the oil is kept at 180–250 °C for 30–180 min [ 15 , 20 ]. Actually, soft deodorization conditions are tailored to avoid the formation of those specific markers [ 21 ], as has been pointed out in recent studies conceived to resolve this problem.…”