Values are means ± standard deviation (*n* = 3), except for the β-carotene value (mean only); values with different letters (a–f) are significantly different (*p* < 0.0001); DGLV—dark green leafy vegetable; OFSP—orange-fleshed sweet potato; PFSP—purple-fleshed sweet potato; and WFSP—white-fleshed sweet potato. ¥ Moisture determined on freshly harvested leaves. † GAE—gallic acid equivalents.

OFSP1, Apomuden, a variety being promoted in Ghana because of the β-carotene content in the storage root [39], had approximately 1.7 times more total polyphenols than the other sweet potato cultivars. The leaves of the sweet potato cultivars were not distinctively superior in the levels of the micronutrients analysed, compared with the other DGLVs. However, OFSP1 contained appreciably higher levels of β-carotene (10,533 µg/100 g) and total polyphenols than the other greens, apart from the β-carotene level in moringa (1.3 times more), and the total polyphenols in baobab, which was about thrice higher. Although the roots of the OFSP cultivars are promoted as a dietary source of vitamin A, moringa leaves actually had the highest β-carotene concentration among the DGLVs investigated. Although the WFSP root is devoid of β-carotene [40], the amount of provitamin A in the leaf was more than that in the greens of OFSP2 and OFSP3. β‐ β‐ μ β‐

In contrast, among the commonly consumed DGLVs, only baobab leaves contained the highest amount of calcium (*p* < 0.001): on average, about four times more. There was no significant difference in the iron concentration (*p* > 0.05), but the data showed that the iron level in baobab and moringa (4.59 ± 1.28 and 4.55 ± 1.88 mg/100 g, respectively) was higher. Previous data indicated that moringa contained 28.29 ± 0.05 mg/100 g of compositional iron [17], the highest compared with the seven sweet potato varieties in Ghana; the data in this study followed a similar trend. β‐ β‐

Three of the DGLVs with notable amounts of ascorbic acid were moringa, baobab, and kenaf. The total polyphenols in baobab was the highest (1646.75 ± 69.44 mg GAE; *p* < 0.001) among all the DGLVs, including the sweet potato cultivars considered in this study. Moringa had a moderate content of total polyphenols, about one-fifth of that in Baobab (*p* < 0.05).

The concentration of zinc in the cocoyam leaf was 1.49 mg/100 g, about thrice more than the average of all the other DGLVs (*p* < 0.001). A similar trend of the zinc data between moringa and the sweet potato cultivars in this study was observed in a previous study in Ghana [17]. ‐

Figure 3 shows the crude protein content of all the DGLVs, ranging from 3.62–6.54 g/100 g on the as-would-be-eaten basis. Moringa contained the highest protein (6.54 ± 0.36 g/100 g), and was significantly different (*p* < 0.05) from the next DGLV, baobab (5.67 ± 0.05 g/100 g), which was followed by two cultivars of sweet potato: OFSP1 (5.37 ± 0.04 g/100 g) and OFSP3 (4.99 ± 0.17 g/100 g). The two DGLVs with the lowest protein levels were WFSP (3.87 ± 0.05 g/100 g) and Cocoyam (3.62 ± 0.17 g/100 g). A trend between the protein data for moringa and the sweet potato cultivars was similar to a previous study in Ghana [17]. ‐ ‐ ‐

‐ ‐ ‐ ‐ ‐ ‐ **Figure 3.** Protein content in "as-would-be-eaten" leafy vegetables. Bar values are means ± standard deviation (*n* = 3); bars with different letters (a–g) are significantly different (*p* < 0.0001). OFSP—orange-fleshed sweet potato (1, 2 and 3); PFSP—purple-fleshed sweet potato; and WFSP—white-fleshed sweetpotato.

#### *3.2. In Vitro Iron Bioaccessibility Using Caco-2 Cells as a Model*

The data representing the in vitro iron bioaccessibility are shown in Figure 4. The overall mean of the iron bioaccessibility was 7.71 ng ferritin/mg protein. Moringa markedly had the best iron bioaccessibility, 10.28 ± 2.73 ng ferritin/mg protein, and was significantly different (*p* < 0.0001) from all the DGLVs investigated. *‐* 

The two greens (baobab and OFSP1) that could be ranked first and second in terms of the concentrations of total polyphenols had the lowest iron bioaccessibility using the Caco-2 cell model; their bioaccessibility was below the group mean. Conversely, cocoyam had an iron bioaccessibility at the overall mean, although it contained the lowest concentration of polyphenols. Apart from baobab, moringa and OFSP1, all the other DGLVs had a bioaccessibility similar to that of the overall mean. ‐

‐ ‐ ‐ ‐ **Figure 4.** Ferritin formation per half a gram of freeze-dried green leafy vegetables. Vertical lines are means with 95% confidence intervals of ng ferritin/mg protein from the various greens (*n* = 12 for corchorus; *n* = 18 for OFSP1, PFSP, baobab, kenaf and moringa; and *n* = 21 for OFSP2, OFSP3, WFSP and cocoyam) normalised to the blank digest ferritin level; horizontal line indicates the overall mean of ng ferritin/mg protein; means with 95% confidence intervals with a different letter (a,b) are significantly different (*p* < 0.0001).

**‐** − **Table 2.** Effect of selected components (on an "as-would-be-eaten" basis) in DGLVs on iron bioaccesibility.

