Fibre and polyphenols of selected fruits, nuts and green leafy vegetables used in Serbian diet

Abstract

Fruits and vegetables are known as good sources of numerous bioactive compounds among which polyphenols and dietary fibre are considered essential because of their protective health effects. The aim of this study was to characterize the quality of selected plant foods of Serbia regarding the amount of total phenols, fibres and ratio of certain fractions of fibre. Fifteen samples of plant foods (green leafy vegetables, fruits and nuts) were evaluated for their total antioxidant activity, total phenolic content, total, soluble and insoluble fibre and fractions of fibre: β-glucans, arabinoxylan, cellulose and resistant starch. Generally, nuts were the richest sources of fibre and total phenols. However, when serving size was taken into consideration, it appeared that raspberry and blackberry were the richest in total, soluble fibre and cellulose. Furthermore, almonds and hazelnuts were particularly rich in insoluble fibre, while walnuts had the highest polyphenol content. The analyzed plant foods were poor sources of arabinoxylan and β-glucan. Data on the presence of resistant starch in cashew nut was the first confirmation that resistant starch could be found in significant amount in some nuts. The results give rare insight into the quality of selected plant foods regarding dietary fibre and polyphenols from the nutritive point of view.