Physicochemical, nutritional and functional properties, rate of polyphenols and flavonoids of the Stenochlaena tenuifolia (BLECHNACEAE) leaves

Abstract

The general objective of this study is to contribute to the promotion of edible wild vegetables available in Madagascar. Its specific objective is to determine the physicochemical, nutritional and functional properties and the polyphenols and flavonoids contents of the Stenochlaena tenuifolia (BLECHNACEAE) leaves. Physical, physicochemical and biochemical methods have been used to characterize the powder from the leaves of this plant. The results obtained showed that the powder of the Stenochlaena tenuifolia leaves has a pH equal to 5.25±0.04 and an acidity equal to 2.57±0.23%. Its water and dry matter contents are respectively equal to 3.35±0.03% and 95.65±0.01%. Its macronutrient content, such as proteins, crude fat and carbohydrates, expressed in grams per 100 grams of dry matter, are respectively 32.30±0.17; 4.27±0.06 and 49.71±0.01. The metabolizable energy provided by this powder (in kcal per 100g) is 292.02±0.01. Its crude ash content is 10.35±0.04%. Its mineral elements content, such as calcium, magnesium, potassium, iron, phosphorus, zinc and copper (in mg per 100 g) of this powder are respectively 81.78±0.29; 287.15±6.60; 3140.59±24.64; 15.64±0.16; 540.90±7.71; 4.91±0.13 and 2.85±0.03. The potential renal acid load of this plant is –52.88. The functional properties, such as water and oil retention capacities, the hydrophilic-lipophilic ratio and the solubility index of the powder produced are respectively 486.29±8.44%; 170.00±8.16%; 2.86 and 20.36±0.20%. Its total polyphenols and total flavonoids contents are respectively 457.01±0.15mg pyrogallol equivalent per gram of dry matter and 15.12±0.23mg quercetin equivalent per gram of dry matter. Therefore, this plant has important nutritional, functional and phytochemical properties. Thus, this wild leaf vegetable can be used to fight against malnutrition and especially protein-energy malnutrition which affects almost the entire population in Madagascar.