Growth Response and Nutrient Content of Cowpea Sprouts Based on Growth Temperature and Genetic Resources

Abstract

The purpose of this study was to establish the optimal growth temperature and to select genetic resources for production of cowpea sprouts. Seowon was treated between 15℃ and 30℃ at intervals of 3℃ to investigate growth temperature. Twelve resources, including Seowon, IT154149, IT154153, Tvu7426, and Tvu7778, were used for cultivating sprouts at a temperature of 27℃. The yield ratio of cowpea sprouts was highest at 27℃ (657%), and was reduced when growth temperature was decreased. The hard seed rate was lower when the growth temperature was increased. Vitamin C content was highest at 24℃ (2.85 ㎎/g), ranged between 2.15 and 2.29 ㎎/g at other growth temperatures, and increased with the length of the growth period. The inorganic component content of cowpea sprouts did not vary based on growth temperature, while the amino acid content increased with increasing growth temperature between 15℃ and 24℃, and then subsequently decreased as growth temperature rose from 24℃ to 30℃. IT154153 had the highest yield ratio of cowpea sprouts per genetic resource (647%), followed by Seowon (615%), and Tvu7426 (608%). Genetic resources with a higher yield ratio had smaller seeds, a thinner seed coat, and superior germinability. The inorganic components found at highest concentrations in the cowpea sprouts were potassium, magnesium, calcium, sodium, iron, molybdenum, and zinc (in that order). In comparison to raw seeds, the protein, calcium, zinc, molybdenum, and iron content in the cowpea sprouts was higher, while the content of aluminum and boron was lower.

Development stage, storage temperature and storage duration influence phytonutrient content in cowpea (Vigna unguiculata L. Walp.)

“…Results revealed that cowpea leaves are a rich source of minerals such as iron, potassium, calcium, magnesium, phosphorus, manganese and zinc ( Table 2 ). The mineral contents in cowpeas in this study was in the same range with some of the green leafy vegetables, including C. gynandra ( Schönfeldt and Pretorius, 2011 ; Okonya and Maass, 2014 ; Kim et al., 2014 ; Omondi et al., 2017 ). However fluctuations can occur due to changes in production conditions, temperature and light just as seen in the carbohydrates dynamics.…”

“…However, calcium decreased with age while Fe and Mn increased ( Table 2 ). Previous studies have reported a wide variability of minerals in different cowpeas cultivars ( Kim et al., 2014 ). However, little information is available about dynamics of mineral elements during the development of leafy vegetables.…”

Cowpea (Vigna unguiculata L. Walp), a renewed multipurpose crop for a more sustainable agri‐food system: nutritional advantages and constraints

“…Nutritionally, cowpea seeds protein shows a prevalence of glutamine/glutamic acid (16.5–18.8 g 16 g −1 N), asparagine/aspartic acid (11.4–13.2 g 16 g −1 N), and phenylalanine + tyrosine (7.5–10.2 g 16 g −1 N), as well as a secondary prevalence of arginine, leucine, lysine, valine and proline . The same ranking is observed in leaves, even though cowpea leaf protein, based on their amino acid content, is more than two‐fold higher (Table ) to that described for seeds (24.3–45.3, 17.0–26.7, and 19.1–23.7 g 16 g −1 N, for glutamine/glutamic acid, asparagine/aspartic acid, and phenylalanine + tyrosine, respectively) …”

“…Thus, potassium is the most abundant mineral in seeds and leaves, with contents ranging from 1.9 to 28.9 g kg −1 . Of particular importance are the high contents of calcium (383–10 620 and 398.0–8050.0 × 10 −3 g kg −1 in seeds and leaves, respectively), zinc (8.1–118.0 and 3.4–129.1 × 10 −3 g kg −1 in seeds and leaves, respectively), and iron (6.9–218.0 and 16.2–772.9 × 10 −3 g kg −1 in seeds and leaves, respectively) . This mineral composition emphasises the value of cowpea fulfilling the recommended daily intake in a similar way as other legumes .…”

“…Cowpea appear to be a particularly good source of vitamin C, with levels in seeds and pods ranging from 52.0 to 554.0 × 10 −3 g kg −1 , and in leaves from 292.0 to 4100.0 × 10 −3 g kg −1 . It is important to note that the total vitamin C content in leaves at the maturity stages (4 and 6 weeks) is mostly in the form of dehydroascorbic acid, an oxidation product of l ‐ascorbic acid, which exhibits a lower biological activity …”