Malnutrition is a global phenomenon that mainly affects children under five years old, the elderly and food insecure people. It can be linked to undernourishment or overnutrition. To prevent it, a healthy and balanced diet, rich in energy and micronutrients, is necessary. The objective of this study was to evaluate the nutritional composition and contribution of tomato by-products to prevent and reduce malnutrition. Thus, standard methods were used for proximate composition and bioactive compounds. Results showed that tomato by-products are rich in macronutrients and micronutrients capable of preventing undernutrition and reducing the incidence of the effects of overnutrition. The average carbohydrate, protein and lipid contents were 15.43%, 11.71% and 5.4% (DM) in peels and for seeds the contents were 58.75%, 15.4% and 22.2%, respectively. The average energy values were 280.47 kcal/100 g and 472.8 kcal/100 g DM for peels and seeds, respectively. The main minerals found were, in decreasing order, potassium, magnesium, sodium, iron and zinc. High contents of phenolic compounds, lycopene, β-carotene and vitamin C were also found in these by-products. They also presented important antioxidant activities. Due to their nutritional and bioactive compounds, tomato by-products may be included in functional food formulation programs to reduce the incidence of nutritional diseases.

Extracts from Hibiscus sabdariffa L. (roselle) have been used traditionally as a food, in herbal medicine, in hot and cold beverages, as flavouring or coloring agent in the food industry. In vitro and in vivo studies and trials provide evidence, but roselle is poorly characterised phytochemically due to the extraction processes. The optimization of the extraction of phenolic compounds and their antioxidant activities is still a hot topic. In this study, the effect of solute/solvent ratio (33, 40 and 50 mg/mL), extraction temperature (40, 50 and 60 °C) and extraction time (30, 60 and 90 min) was evaluated through the content of phenolic compounds and antioxidant activity. A response surface methodology through a Box–Behnken design was applied and model fit, regression equations, analysis of variance and 3D response curve were developed. The results showed that TPC, TFC, DPPH and FRAP were significantly influenced by temperature, extraction time and solvent/solute ratio. Thus, TPC, TFC, DPPH and FRAP varied from 5.25 to 10.58 g GAE/100 g DW; 0.28 to 0.81 g QE/100 g DW; 0.24 to 0.70 mg/mL; 2.4 to 6.55 g AAE/100 g DW respectively. The optimal experimental condition (41.81 mg/mL; 52.35 °C and 57.77 min) showed a significant positive effect compared to conventional methods. The experimental values at this extraction condition show that this optimization model is technologically, financially and energetically viable as it requires a reasonable concentration, time and temperature.

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This study consisted of the physicochemical, phytochemical and antioxidant characterisation of two varieties of Hibiscus sabdariffa, to evaluate the influence of genetic and environmental factors on these parameters leading to an objective and rigorous classification of our extracts. To this end, calyxes and seeds of the red and white phenotypes were collected in Bobo-Dioulasso, Dano and Nouna respectively in December 2019 and 2020. Principal component analysis showed that physico-chemical and biochemical parameters could potentially be used to discriminate varieties. The calyxes of the sabdariffa variety showed the best physicochemical profile (total phenolics, flavonoids, ascorbic acid), pigments (anthocyanins, chlorophyll) and antioxidant activity (free radical scavenging and SOD activity) while the seeds showed the best carbohydrate, lipid and peroxidation inhibition content. In view of these results, the red phenotype has an interesting nutritional and therapeutic potential. It could therefore be interesting candidate in the pharmaceutical and food industries.

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