**4. Sweet potato production statistics**

Globally, in 2020, sweet potato was cultivated on 7.4 million hectares (mha) that produced 89.49 million tonnes (mt) of edible roots, with a mean yield of 12.1 t/ha [11]; about 95% of the global sweet potato production occurs in developing countries. In 2020, Asia stood first by producing 55.98 mt of roots from 2.785 mha, followed by Africa with 28.80 mt from 4.214 mha, Americas 3.81 mt from 0.253 mha and Oceania 0.90 mt from 0.149 mha. In 2020, mean yield of sweet potato was the highest in Asia (20.1 t/ha), followed by Americas (15.1 t/ha), Africa (6.8 t/ha) and Oceania (6.1 t/ha) (**Figure 1**).

China, Indonesia, Vietnam, Angola, Ethiopia, Malawi, Nigeria, Tanzania, Uganda, and USA are the top 10 sweet potato producing countries. The area harvested, yield, and production of roots for 2010, 2015 and 2020 are provided in **Table 1**. China is the largest producer and consumer of sweet potato in the world. Sweet potato yields increased steadily from 2010 to 2020 in most countries. During the period of

#### **Figure 1.**

*Global and region-wise sweet potato production statistics, 2020 [11].*


#### **Table 1.**

*Area harvested, yield, and total production of sweet potato in selected countries.*

2015–2020, national average sweet potato yields stabilized around 27 t/ha in Ethiopia, 23 t/ha in the USA, 21 t/ha in China and Malawi, 18 t/ha in Indonesia, and 11 t/ha in Vietnam and Angola; sweet potato productivity was very low at 4–6 t/ha in Nigeria, Tanzania, and Uganda [11].

Globally and in Asia, the sweet potato area and root production have been going down steadily from 1994 to 2020. Africa is the only region where sweet potato area and production have been steadily increasing with time [11].

### **5. Sweet potato: nutrients profile**

Sweet potato is rich in carbohydrates, fibre, vitamins, micronutrients, and plant compounds that have antioxidant properties.

#### **5.1 Edible roots**

The average composition of fresh sweet potato roots is water (77%), carbohydrates (20.1%), sugar (4.2%), fibre (3%), protein (1.6%), and fat (0.1%) (**Table 2**). Most of the carbohydrates come from starch (17%) and fibre (3%). The soluble fibres (15–23%) are mostly pectin which may increase fullness while eating, decrease food intake, and reduce blood sugar spikes; the insoluble fibres (77–85%) are composed of cellulose, hemicellulose, and lignin. Although protein content is low (1.6%), 80% of the total proteins are composed of sporamin which may have antioxidant properties. All sweet potato varieties also contain variable amounts of vitamins A; B1, B2, B3, B5, B6 and B9; C and E; and low levels of vitamin K, and high levels of potassium and medium levels of calcium, magnesium, phosphorus, and trace elements such as iron, manganese, zinc, copper, and selenium [12].

It provides 86 calories per 100 g of boiled roots. Glycaemic index (GI) of cooked sweet potato is medium to high (44–96). Boiling is linked with lower GI values than baking, frying or roasting [13, 14]. Therefore, people with type 2 diabetes must be careful not to consume too much sweet potato.

Sweet potato is rich in many plant compounds: beta carotene, anthocyanins, chlorogenic acid. The purple-skinned sweet potato contains anthocyanins and chlorogenic acid that have antioxidant properties. The OFSP varieties are rich in beta-carotene the precursor of vitamin A. Breeding, distribution, and promotion of high-yielding OFSP varieties is critical to reduce the widespread deficiency of vitamin A and minerals such as iron and zinc in most developing countries [15]. A daily intake of 125 g of OFSP will satisfy the daily vitamin A needs of below 5-year-old children [16].

Purple-fleshed sweet potatoes rich in anthocyanins [17] are used in juices, alcoholic beverages, jams, confectionaries, bread, snacks, and noodles.

#### **5.2 Vines and leaves**

Sweet potato vines with leaves are equally valuable as human food. Young vines with tender leaves are boiled or steamed with salt and condiments and consumed as a vegetable. They are low in carbohydrates (7.4%), beta carotene [1725 micrograms per 100 grams (mcg/100g)], sodium, vitamin B5, and micronutrients such as copper and selenium, but richer in protein, fat, all B vitamins except B5, and vitamins E and K than the roots (**Table 2**). Leaves also contain some plant compounds that exhibit antioxidant properties [18].


*Sweet Potato (*Ipomoea batatas *(L.) Lam): A Review of Modern Varieties and Production… DOI: http://dx.doi.org/10.5772/intechopen.106586*

#### **Table 2.**

*Nutrient profiles of fresh sweet potato roots and steamed vines + leaves.*

Sweet potato vines are excellent fodder for animals. Vines are periodically cut and fed to animals such as cattle, goats, sheep, and pigs. The vines can also be preserved as silage or hay for feeding animals during dry periods or summer when other fodders are scarce. An added advantage is that animals fed with sweet potato vines produce less methane [19], a potent greenhouse gas that cause climate change.
