Strawberry

• The strawberry (Fragaria x ananassa) belongs to the Rosaceae family.
• It is one of the most popular nutritious fruits among the berries (Mishra, 2014).
• It is cultivated in almost all countries of the world (Mishra, 2014).

PHYSICAL AND ORGANOLEPTIC CHARACTERISTICS

• Strawberry is a very attractive bright red coloured fruit, due to the presence of anthocyanins, the main one being pelargonidin-3-glucoside (Mishra, 2014).
• It is a non-climacteric fruit (Pech, 2018), whose colour changes during ripening from green-white to dark red in about 40 days after anthesis (Schwieterman, 2014).
• Strawberries are also characterised by their lack of firmness (Schwieterman, 2014). During ripening, the pH increases while the acidity and firmness of the fruit decreases (Ornelas-Paz, 2013).
• Their aroma consists mainly of a complex mixture of esters, aldehydes, alcohols and sulphur compounds (Mishra, 2014). To date, more than 350 volatile compounds have been identified in strawberries, but only a dozen contribute significantly to the aroma of this fruit, especially furaneol (4-hydroxy-2,5-dimethyl-3-(2H)-furanone) (Song, 2016; Yan, 2018).
• Esters, such as methyl and ethyl butanoates and hexanoates, are also thought to be important contributors to the aroma of this fruit (Mishra, 2014; Cruz-Rus, 2017).
• Linalool (monoterpenol) has been associated with a floral and sweet aroma while furanol while its methoxylated derivative mesifuran (2,5-dimethyl-4-methoxy-3 (2 H)-furanone) (furanones) is thought to be responsible for the fruity and caramel aromas. Other key compounds such as γ-decalactone and γ-dodecalactone, contributing to fresh peach aroma, have been associated with the perception of increased sweetness in strawberries (Cruz-Rus, 2017; Ulrich, 2016; Yan, 2018).
• However, there are differences in aroma among the multiple cultivars (Mishra, 2014).
• The ripening of strawberries leads to accumulation of several sugars and organic acids in addition to the volatile compounds that constitute their aroma (Ménager, 2004; Nunes, 2006; Kafkas, 2007; Schwieterman, 2014).
• The minor acidic note is due to the presence, to a greater or lesser degree, of organic acids, mainly citric and malic acids (Mikulic-Petkovsek, 2012). The main organic acids tend to increase irregularly during strawberry ripening (Ornelas-Paz, 2013).

COMPOSITION CHARACTERISTICS (excluding macronutrients, vitamins and minerals)

• A common denominator in the pathogenesis of most chronic inflammatory diseases is the involvement of oxidative stress, related to the production of ROS (Gasparrini, 2017). Several in vitro and in vivo studies have reported the effects of strawberry extracts on the suppression of oxidative stress and the inflammatory process. The polyphenols contained in strawberries are believed to be responsible for these beneficial properties (Battino, 2020).
• Epidemiological and clinical studies show that acute consumption appears to improve postprandial glycemic response. At the same time, prolonged intake is reported to improve plasma lipid profile, promoting cardiovascular health, especially in those at increased risk of metabolic syndrome (Forbes-Hernandez, 2016).
• To explain their beneficial effects, much attention has been paid in the past to the antioxidant properties of strawberry polyphenols. However, recent research has shown that their biological and functional activities are related not only to antioxidant capacity but also to the modulation of many cellular pathways involved in metabolism, survival, proliferation and antioxidant defences (Forbes-Hernandez, 2016).
• Generally speaking, phenolic acids (hydroxycinnamic and hydroxybenzoic acids) are in the majority in strawberries, followed by anthocyanins, flavonols and flavan-3-ols (Seeram, 2006; Kosińska, 2013; Nowicka, 2019).
• Among the phenolic acids, ellagic acid and coumaric acid derivatives are generally predominant. While pelargonidin-3-glucoside is the major anthocyanin in strawberry, the presence of cyanidin-3-glucoside and pelargonidin-3-acetylglucoside has also been reported (Bakker, 1994; Lopes-da-Silva, 2002).
• Other compounds usually include quercetin and kampferol derivatives (flavonols), as well as catechin and procyanidins (flavan-3-ols). The latter compounds may also be present in large amounts but in condensed form (proanthocyanidins) (Enomoto, 2019).