*2.3.1 Genetic variation*

The polyphenol content of various plant varieties or cultivars varies. Genetic factors play an important role in determining the types and amounts of polyphenols present in different plant species [18].

*Polyphenol Extraction for the Enhancement of Food Lipid Quality, with an Emphasis… DOI: http://dx.doi.org/10.5772/intechopen.112946*

### *2.3.2 Agricultural practises*

Agricultural practises, such as fertilisation, irrigation, and pesticide application, can affect the polyphenol content of food sources. Montesano et al. [19] report that organic farming methods and sustainable agricultural practises increase polyphenol levels compared to conventional methods. The environment, including climate, exposure to sunlight, and soil composition, can have an effect on polyphenol synthesis in plants. As a defence mechanism against oxidative stress, increased ultraviolet (UV) radiation exposure can stimulate the synthesis of certain polyphenols [20].
