Table 4 Concentrations of the most prevalent polyphenols observed in the black beans ¹ (nmol/g)

Caffeic acid

6.0 ± 0.9^b

25.8 ± 4.7^a

Gallic acid

125.0 ± 8.8^a

103.3 ± 17.8^a

Ferulic acid

153.0 ± 11.1^a

162.5 ± 20.1^a

Kaempferol

5.0 ± 0.1^a

0.00 ± 0.00^b

Catechin

668.8 ± 31.1^a

367.5 ± 25.5^b

Myricetin

24.0 ± 1.7^a

12.5 ± 4.0^b

Kaempferol 3-glucoside

198.0 ± 10.7^a

19.2 ± 5.6^b

Quercetin 3-glucoside

239 ± 20.3^a

45.8 ± 7.9^b