Effect of thermal processing and fermentation on the nutritional composition and techno-functional properties of monkey pineapple (Myrianthus arboreus) seeds

Processing methods can improve the nutritional quality of non-conventional fruits and promote their consumption. The aim of this study was to assess the influence of culinary treatments on the nutritional composition of Myrianthus arboreus seeds. The proximate composition and antinutrients of crude seeds were evaluated. Furthermore, fatty acid profile, chemical quality and digestibility of their oil, amino acid profile and digestibility of their proteins were determined. Finally, the influence of fermentation, bleaching and boiling was assessed on the lipid, protein, anti-nutrient contents and on the techno-functional properties. The crude seeds possessed 15.90%, 7.94%, and 65.20% of lipids, proteins and carbohydrates respectively. Potassium (3516.20 mg/100g) was the preponderant mineral. Linoleic acid (91.81%) and lysine (0.25 mg/g) were the most represented. The hydrocarbon chains of lipids and the peptide bonds of proteins were accessible to hydrolytic enzymes. Fermentation after 5 days reduced to a lesser extend the lipid content by 41.82%. For proteins, only boiling improved their content by 35.26%. Boiling reduced oxalate more effectively (98.67%). Fermentation reduced cyanide (43.48%) on day 7 and saponins (32.92%) at all times. But it increased total phenol by 28.64% on day 1. Bleaching reduced condensed tannins (90.94%). All treatments reduced completely hydrolysable tannins and trypsin inhibitors. Culinary treatments increased water absorption capacity (20 to 30%), swelling rate (58.39 to 75%) and hydrophyl-lipophilic index (0.67 to 1.5%) but, reduced oil absorption capacity (30 to 20%). Processing methods influence on the nutritional composition and the techno-functional properties of M. arboreus seeds. These characteristics would be suitable in formulating infant flours.