Browsing by Author "Ben Rhouma, Hiba"
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- Comparison of nutritional and bioactive properties of acorn flour with and without tanninsPublication . Ben Rhouma, Hiba; Carocho, Márcio; Barros, LillianThe Quercus spp. are a varied group of evergreen and deciduous trees native to temperate and tropical regions. There are about 600 species of Quercus worldwide, which differ in their flowering and fruiting dynamics as well as maturity index. Acorns, the nuts of Quercus spp. trees, offer a comprehensive nutritional profile, being rich in proteins, fibers, starch, bioactive compounds including tannins and phenolic acids, essential vitamins, like vitamins A and E, and minerals, such as potassium, iron, calcium, and magnesium. However, this fruit presents a problem for the food industry regarding the astringency caused by tannins, which are anti-nutrients found in acorns. Therefore, this study aims to evaluate the potential of acorn flour for the baking industry by comparing the nutritional value and bioactive compounds of acorn flour with and without tannins. The whole flour (SPM21) and a tannin-free flour (SPM21F4) were analysed, having both been supplied by the company Landratech. The elimination of tannins, which was accomplished by leaching the flour three times with water at 15 °C, resulted in a reduction in several nutrients, such as crude protein, ash, and fiber. However, the SPM21F4 flour showed increased levels of moisture, crude fat, starch, total carbohydrates, and energy content. Soluble sugars were found exclusively in the SPM21 flour, indicating that the leaching treatment affected the sugar content in the SPM21F4 sample. The fatty acid profile of the SPM21F4 flour revealed higher levels of polyunsaturated fatty acid (PUFA) and monounsaturated fatty acid (MUFA), while the flour containing tannins had higher levels of saturated fatty acids (SFA). Ten phenolic compounds were detected, and the tannin free flour had a much lower overall phenolic content. In conclusion, properly processed acorn flour can improve the nutritional profile of bread by providing bioactive chemicals and appealing sensory features, hence increasing its popularity in the baking business. However, further research is needed to optimize tannin extraction and fully understand the nutritional and industrial potential of acorn flour.