Natural Fermentation of Cowpea (Vigna unguiculata) Flour Improves the Nutritive Utilization of Indispensable Amino Acids and Phosphorus by Growing Rats

Abstract

Cowpea (Vigna unguiculata) is among the most cultivated legumes, with interesting agronomic and environmental properties, and great potential as a nutritious food. The nutritional value of cowpea can be improved by technological processing. In this study, we showed that natural fermentation improved bioavailability of protein, amino acids, and dietary essential minerals from cowpea in growing rats, thus strengthening its potential value as functional food or food supplement. Forty Wistar albino rats (48 ± 1.8 g), were fed one of four experimental diets (n = 10 rats per diet): casein, raw cowpea, fermented cowpea or fermented and autoclaved cowpea. Despite lower growth indices of raw and fermented cowpea protein (PER, FTI) than casein, fermentation enhanced apparent digestibility of arginine, leucine, lysine, methionine, phenylalanine, tyrosine, and valine, and true digestibility of essential amino acids, except for tyrosine and valine, compared to raw cowpea. On the other hand, autoclaving of fermented cowpea flour decreased apparent, as did true digestibility of sulfur amino acids. Regarding the nutritive utilization of dietary essential minerals, Vigna unguiculata was a good source of available P, Mg, and K, while fermentation significantly improved the availability of P. Overall, cowpea was a good source of digestible essential amino acids and minerals and fermentation significantly improved its nutritional value that was not further enhanced by autoclaving.

Biochemical properties, nutritional quality, colour profile and techno‐functional properties of whole grain sourdough and malted cowpea and quinoa flours

“…Among all the assayed minerals, potassium, phosphorus, magnesium and calcium were abundant in the flour samples. Previous studies also showed that raw cowpea and quinoa flours are good sources of macrominerals (Marmouzi et al, 2015;Kapravelou et al, 2020). The sourdough flours displayed significantly (P ≤ 0.05) higher levels of the minerals and strongly correlated with their higher ash contents (4.17% and 4.42%, Table 2).…”

“…Among all the assayed minerals, potassium, phosphorus, magnesium and calcium were abundant in the flour samples. Previous studies also showed that raw cowpea and quinoa flours are good sources of macrominerals (Marmouzi et al ., 2015; Kapravelou et al ., 2020).…”

“…(2020) also reported no significant difference in the iron contents of raw and whole soybean sourdough. Nevertheless, the mineral result from this study agrees with the increases in calcium, magnesium, potassium, phosphorus, copper and manganese contents reported for quinoa sourdough and fermented cowpea flours (Chiş et al ., 2020; Kapravelou et al ., 2020).…”

“…Fermentation and malting are traditional and inexpensive bioprocessing methods used to convert food grains into intermediate/final products. These products offer desired and improved food features: nutrient composition, technological and sensory properties, as well as enriched healthy food components and reduced antinutritional factors (Kapravelou et al ., 2020; Kewuyemi et al ., 2020; Chinma et al ., 2021a). As such, these processing techniques hold potential for the continuing valorisation of less biomodified and underutilised WG crops (Adebo & Medina‐Meza, 2020; Kewuyemi et al ., 2020).…”

Challenges, Progress and Prospects for Sustainable Management of Soilborne Diseases of Cowpea

“…The mineral content ranged from 1.97 to 2.69 mg/100 g for calcium, 3.23 to 3.90 mg/100 g for magnesium, 205.53 to 223.30 mg/100 g for sodium, 0.80 to 1.23 mg/100 g for zinc, 1071.15 to 1152.62 mg/100 g for potassium and 0.62 to 1.06 mg/100 g for phosphorus. Cowpea has shown great potential for production of fermented yoghurt-like food products with improved bioavailability of nutrients [13,14]. Cowpea is rich in phenolic acids such as benzoic and cinnamic acid derivatives that are associated with antioxidant properties [15].…”