Avaliação da composição nutricional da casca do fruto de Canhú (Clerocarya birrea) usado como condimento alimentar

Abstract

The marula tree (Sclerocarya birrea), a native plant of Southern Africa, is found in Mozambique, with the exception of Nampula Province. Its fruits are consumed fresh or processed to produce beverages, which generates large amounts of waste, such as peels and seeds. Duo to high production levels and a short post-harvest shelf life, there is significant waste, worsened by the lack of processing strategies, despite the fruit ’ s nutritional value. The use of techniques such as drying and the production of by-products can add economic value and generate income for local communities. The peels, although nutritious and rich in bioactive compounds, vitamins, minerals, pectins, and fibers, are often discarded improperly, causing negative environmental impacts. The present study aimed to evaluate the nutritional and minerals composition, as well as to identify secondary metabolites of canhú peels. The peels selected after harvesting were pre-cleaned and divided two equal positions, then subjected to two drying methods: natural drying in the laboratory for 336 hours, and oven drying with air circulation at 65 o C for 72 hours. The samples were then ground in a food processor and sieved to obtain fine particles (flour), which after which laboratory analysis was conducted. The average levels of the analyzed parameters under natural and artificial drying were: moisture (7.20% and 6.55%); ash (7.71% and 6.86%); crude fiber (23.69% and 25.42%); fat (4.50% and 4.74%); protein (7.09% and 10.27%); carbohydrates (57.0% and 52.69%); caloric value (296.89 kcal and 294.56 kcal); pH (4.40 and 4.33); total titratable acidity (5.53% and 6.36%); and total soluble solids (3.0% and 3.50%), for natural and artificial drying, respectively. The mineral contents were: Na (0.3 mg/100 g and 0.25 mg/100 g); K (6.57 mg/100 g and 5.84 mg/100 g); Ca (37.5 mg/100 g and 33.5 mg/100 g); Mg (4.25 mg/100 g and not detected), for natural and artificial drying, respectively. Iron (Fe) and phosphorus (P) levels were not detected. As for tannins, flavonoids, and saponins, these tested positive in the naturally and artificially dried marula fruits peels. The drying methods used proved efficient both for producing the flour and for evaluating the nutritional parameters. The results obtained indicate a considerable nutritional value for the use of cashew peels as food.