*7.4.3 Spiced jam*

Fruit jams are important in the diet and eaten by people of all ages. In order to improve the nutritional content and the health functionality of jams, produced watermelon, apple and pineapple jams spiced with garlic, ginger and/or turmeric. A good jam which has a soft even consistency and exhibits a high nutritional and antioxidant quality was produced. The total soluble solid and total titratable acidity were found to be within recommended range by Codex Alimentarius [139].

*Nigeria Root Vegetables: Production, Utilization, Breeding, Biotechnology and Constraints DOI: http://dx.doi.org/10.5772/intechopen.106861*

#### *7.4.4 Oleoresin*

Oleoresins are commonly used in many industries because of their strong aroma and flavor. They possess some advantages over raw or dried spices as flavoring agents [140]; their flavors are 5–20 times stronger than that of the corresponding spices and they are commonly sold as spice drop. Oleoresins are essential oils, their microbiological advantages, uniformity in flavor, pungency, and ease of storage and conveyance made them to be preferred. For a good yield of oleoresin, ginger should be harvested at 7–8 months after planting [141]. Through the collaboration of the Raw Materials Research and Development Council (RMRDC) and Belphins Nigeria Ltd., Kaduna State ginger oleoresin was produced in Nigeria which showed favorable physicochemical and microbial properties [142]. The traditional method is usually a manual process which entails preliminary processing and hand pressing while the improved method comprise of chemical extraction and mechanical expression. Locally, the demand for ginger oleoresin is on the increase from both food and pharmaceutical industries but local production has not been able to meet the demand; there is still a dependence on importation. Therefore, the country has huge potentials for expanding oleoresin production to take advantage of the ever expanding local and global oleoresin market.

### **7.5 Nutraceuticals**

The awareness and concerns for the physical wellbeing of humans has been a major driving force for the nutraceutical market in Africa. The inclusion of nutraceuticals in the diet is gaining popularity because they are considered to be natural, safe with less side effects compared to products that are chemically derived. The processing of nutraceuticals has become a means of livelihood especially in the South-west and South-east of Nigeria. Based on industry reports, nutraceuticals market value of Africa is projected to be over USD 430 billion by 2025 and it's expected to register a good Compound Annual Growth Rate (CAGR) of 6.05% during the projected period of 2020–2025 [143]. Nigeria, Namibia, Morocco and Egypt are markets said to drive the sales of pet nutraceuticals. Neutraceuticals in Nigeria are mainly herbs, medicinal and aromatics. The industry is active but small in value involving traditional productions.

#### **7.6 Chemical and nutritional composition of root vegetables**

The place of cultivation and postharvest treatments influence variation in the chemical and nutrient components of root vegetables. **Tables 6** and **7** shows the nutritional composition and chemical components of some root vegetables in Nigeira; with the highlights of nutrients, antioxidant and antimicrobial properties presented below.

#### *7.6.1 Nutrients*

Root vegetables like ginger, onions, garlic and turmeric are known for their rich mineral and very low fat content. Many Root vegetables have absolutely no calorie content thereby making it a weight loss diet. Root vegetables contain significant quantities of minerals such as magnesium, iron, calcium, and potassium.


#### **Table 6.**

*Nutritional composition of selected root vegetables in Nigeria.*


#### **Table 7.**

*Chemical components and health benefits of selected root vegetables.*
