Fatty acid ethyl esters (FAEE) in virgin olive oil: A shorter and full validated approach as an alternative to the EU Official Method.

In this work a SPE/GC-FID method, incorporating the use of a 1-g silica cartridge, for the determination of FAEE in olive oils is presented. The procedure has been fully validated, initially 'in-house' and subsequently by an international validation study involving sixteen laboratories from Europe, the United States of America, and China. Key performance parameters of the method are: (1) Linearity in the 10-134 mg/kg range (R2 > 0.999), (2) LOD and LOQ < 0.5 mg/kg, (3) RSDr < 10%, (4) RSDR < 20% (for 4 out of 5 test materials). In addition, the method has been demonstrated to provide equivalent results to the Official Method (Commission Regulation 2568/91) while providing advantages in terms of reductions in time and solvents and ease of automation. In fact, the proposed protocol requires 30 mL solvents and takes 1.5 h per determination instead of the 350 mL and 6 h needed in the UE Official Method.

Investigating the influence of selected texture-improved pretreatment techniques on storage stability of wholegrain brown rice: Involvement of processing-induced mineral changes with lipid degradation.

This work aimed at investigating the effects of emerging texture-improved processing techniques including high hydrostatic pressure (HHP; 150-450MPa/10min), high-intensity ultrasonication (HIU; 17.83W·cm-2/30min) and germination (37°C/36h) pretreatments on lipid hydrolysis and oxidation development of wholegrain brown rice (WBR) during storage, in an attempt to ascertain a possible link between lipid degradation and the underlying mechanisms. The results showed that HHP and HIU treatments enhanced lipid hydrolysis and oxidation as indicated by the formation of free fatty acids (FFA) and thiobarbituric acid reactive substances (TBARS) respectively, whereas an opposite pattern was observed for germination. Storage process rather than after immediate treatments observed an increase in lipid oxidation of HHP and HIU-processed samples, which was related to processing-induced liberation of minerals. Quantitative and qualitative characterization via inductively coupled plasma-optical emission spectrometry (ICP-OES) and micro X-ray fluorescence (µ-XRF) analysis confirmed the shifts of mineral distribution in WBR grains in response to different pretreatments. The WBR-derived lipase was activated by Ca2+, and µ-XRF mapping indicated calcium enrichment in pericarp/aleurone layer and its mobilization to embryo during germination process where magnesium and manganese were significantly reduced. Multivariate analysis revealed a close relationship between increased lipid degradation and minerals including magnesium and manganese. This is the first time for reporting the effects of selected texture-improved techniques on lipid stability of WBR grains across storage process as well as validating the involvement of processing-induced mineral release in lipid degradation.

Effect of olive storage conditions on Chemlali olive oil quality and the effective role of fatty acids alkyl esters in checking olive oils authenticity.

The present paper accounts for the study of the storage of Chemlali olive fruits at two conditions of limited aerobiosis: in closed plastic bags and in open perforated plastic boxes for different periods before oil extraction. The ultimate objective is to investigate the effect of the container type of the postharvest fruit storage on the deterioration of the olive oil quality. The results have shown that the oil quality of Chemlali olives deteriorated more rapidly during fruit storage in closed plastic bags than in perforated plastic boxes. Therefore, the use of perforated plastic boxes is recommended for keeping the olives for longer periods of storage. The repeated measures analysis of variance of all parameters analyzed indicated that the olive oil quality is mainly affected by the olives storage conditions (containers type and storage periods). Finally, blends of extra-virgin olive oil and mildly deodorized low-quality olive oils can be detected by their alkyl esters concentrations.