The challenge of exploiting polyphenols from olive leaves: addition to foods to improve their shelf‐life and nutritional value

Abstract

Olive leaves represent a waste from the olive oil industry which can be reused as source of polyphenols. The most representative phenolic compound of olive leaves is the secoiridoid oleuropein, followed by verbascoside, apigenin-7-O-glucoside, luteolin-7-O-glucoside, and simple phenols. The attention towards these compounds derives above all from the large number of studies demonstrating their beneficial effect on health, in fact olive leaves have been widely used in folk medicine in the Mediterranean regions. Moreover, the growing demand from consumers to replace the synthetic antioxidants, led researchers to conduct studies on the addition of plant bioactives in foods to improve their shelf-life and/or to obtain functional products. The current study overviews the findings on the addition of polyphenol-rich olive leaf extract (OLE) to foods. In particular, the effect of OLE addition on the antioxidant, microbiological and nutritional properties of different foods is examined. Most studies have highlighted the antioxidant effect of OLE in different food matrices, such as oils, meat, baked goods, vegetables, and dairy products. Furthermore, the antimicrobial activity of OLE has been observed in meat and vegetable foods, highlighting the potential of OLE as a replacer of synthetic preservatives. Finally, several authors studied the effect of OLE addition with the aim of improving the nutritional properties of vegetable products, tea, milk, meat and biscuits. Advantages and drawbacks of the different use of OLE were reported and discussed.

Chemical compounds, antioxidant properties and antimicrobial activity of olive leaves derived volatile oil in West Anatolia

“…Olive leaf is the origin of many phytochemicals such as polyphenolics and flavonoids, which accomplish many antioxidant, antibacterial, antifungal, and anti-inflammatory activity (2)(3)(4)(5)(6)(7)(8)(9)(10). In folk medicine, it is reported that the decoction prepared from the leaves is used for hypertension, arrhythmia, intestinal muscle spasms, and cancer treatment (11)(12)(13)(14).…”

Background, Applications and Issues of the Experimental Designs for Mixture in the Food Sector

“…It is in those areas that efforts should be made to improve the knowledge about the advantages of the use of MD approaches. For example, recovery of bioactives from foods or food by-products has become an hot topic in recent years [31][32][33] but, despite this interest, in our research only few works have been found that optimize the extraction mixtures according to MD.…”

Biscuit Contaminants, Their Sources and Mitigation Strategies: A Review

“…Olive leaf extracts (OLE), rich of phenolics, exerted a strong antioxidant activity in baked dry snacks, slowing down the lipid oxidation. In detail, OLE induced a decrease of 27% in volatile compounds originated from oxidation and of 42% in TGPs compared to control [179,180]. The use of OLE could easily be transferred to biscuits, due to their similarity with baked dry snacks in terms of lipid content, moisture content, and production process.…”