Activity of two natural additives in improving the stability of virgin olive oil quality during storage

Abdelali Boussakouran,El Hassan Sakar,Mohamed El Yamani,Yahia Rharrabti

doi:10.1051/ocl/2020039

Abstract

The activity of natural additives against the deterioration of virgin olive oil (VOO) in relation to storage time and conditions was examined. Thus, carotenoids and phenols previously extracted from carrot and olive mill wastewater, respectively, were added at 200 and 400 ppm to VOO and stored in clear and amber glass bottles at room temperatures during 120 days. The results showed that enriched VOO was largely influenced by the storage time, which resulted in a significant accumulation of hydrolysis and oxidation products. Storage conditions also affected considerably the enriched VOO. Dark glass bottles offered better protection against oxidative deterioration. The impact of both extracts on the oxidation status of examined VOO was significant and concentration-dependent. The natural additives markedly delayed the formation of hydroperoxides and conjugated dienes and trienes. Results from principal component analysis (PCA) showed that most of the variation was captured by the PC1 (89% of the total variance) which grouped samples in four categories according to storage times, each being divided into two clusters linked to storage conditions. Findings from this study revealed that natural additives could minimize VOO deterioration caused by storage time and conditions (light).

Highlights

Olive oil happens to be considered as “the magic elixir of the Mediterranean diet” known for its worldwide appreciation due to its healthy and nutritional aspects that can lead to prevent and reduce the risk rates of many chronic, neurodegenerative and cardiovascular diseases (Huang and Sumpio, 2008; Cicerale et al, 2010; Rizzo et al, 2014).The nutritional value of olive oil is associated to its composition of fatty acids especially the oleic acid and to its richness of natural antioxidants such as phenolic compounds, tocopherols, flavonoids and carotenoids (Covas, 2007; Stefanoudaki et al, 2010)
The results for the legal parameters (FFA, peroxide value (PV), K232 and K270) are listed in Table 1, and indicated that the examined oils belong to the virgin olive oil (VOO) category (EEC, 2003)
Carotenoids and phenols extracted from carrot and olive mill wastewater, respectively, were added at different amounts to VOO and stored in clear and amber glass bottles at room temperatures during 120 days

Summary

Introduction

Olive oil happens to be considered as “the magic elixir of the Mediterranean diet” known for its worldwide appreciation due to its healthy and nutritional aspects that can lead to prevent and reduce the risk rates of many chronic, neurodegenerative and cardiovascular diseases (Huang and Sumpio, 2008; Cicerale et al, 2010; Rizzo et al, 2014).The nutritional value of olive oil is associated to its composition of fatty acids especially the oleic acid and to its richness of natural antioxidants such as phenolic compounds, tocopherols, flavonoids and carotenoids (Covas, 2007; Stefanoudaki et al, 2010). The oxidative reactions that could occur in oil, especially during storage, impact negatively its nutritional quality and flavor, due to the formation of undesirable volatile compounds potentially toxic for human health (Duh et al, 1992; Kiokias and Gordon, 2004; Pan et al, 2007; Ghanbari Shendi et al, 2018, 2020). Auto-oxidation is the most frequent phenomena that proceeds via three cyclical stages, namely induction, propagation and termination (BrandWilliams et al, 1995). Alkyl radicals are formed and undergo a reaction with oxygen molecules to form hydroperoxides and peroxy radicals during the propagation phase. These unstable compounds generate secondary oxidation products (i.e. alkanes, alcohols, aldehydes and acids). Many studies have shown that deterioration reactions of olive oil are more pronounced at longer storage periods (Rodrigues et al, 2016; Di Serio et al, 2018), and are stimulated by oil exposure to light and air (Pristouri et al, 2010; Li et al, 2014; Houshia et al, 2019)

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