**3. Spices as colourants**

The spices are the food additives that are mainly added to impart flavour. Besides, they can also be used as a colouring agent due to the presence of several chemical compounds, the principal compound responsible for the colour are the carotenoids, such as beta carotene, lutein, and neoxanthin [8].

The most common spices used for colouring are turmeric, red pepper, saffron, kokum and tamarind. Other compounds that provide these colouring properties to spices are flavonoids with yellow colours – curcumin and chlorophyll with green (**Table 1**). Spices provide strong colour pigments commonly between orange, yellow, and red, this can be advantageous since spices can be used as natural colourants especially for food. Using spices as colourants in food is a natural alternative that avoids the use of conventional synthetic colourants.

#### **3.1 Turmeric**

*Curcuma longa* L. belongs to the family Zingiberaceae. It is mainly used as a food additive, preservative and colouring agent. The economic part is a rhizome that yields a phenolic compound Curcumin (3–4%). Some of the varieties rich in Curcumin are CIM-Pitamber (12.1%), Suroma (9.3%), Rajendra Sonia (8.1%), Varna (7.8%) and cultivars such as Wayanad Local (9.5%) and Duggirala (7.5%) [15].

#### **3.2 Properties of curcumin**



#### **Table 1.**

*Spice bio-colours and their applications.*

*Bio-Colours From Spices DOI: http://dx.doi.org/10.5772/intechopen.109830*


#### **3.3 Extraction of curcumin**

Curcumin is extracted from the dried root of the rhizome *C. longa*. For extraction, the raw materials are crushed to make into powder form and are treated with a specific solvent to obtain the required coloured compound. After distillation, the obtained product called as oleoresin is a mixture of volatile oils along with other extracts produces about 25–35 per cent coloured compound. The oleoresins are then subjected to further washes using selective solvents that can extract the curcumin pigment from it. This process yields a purified food colour which is known as Curcumin. It contains 90 per cent colouring matter and very little volatile oil and other dry matter. The extractability and regulatory criteria depend on the selection of solvent [17].

#### **3.4 Chilli**

*Capsicum annuum* is one of the major spices used as a natural flavouring and colouring agent. Its extract contains carotenoid pigment Capsanthin which has a major role in the food industry. Paprika oleoresin is manufactured by solvent extraction of the dried capsicum pods. One kg of pods yields 90 to 120 g of extract. Varieties and cultivars rich in capsanthin: KTPL - 19 (233.70 ASTA), Bydagi chilli (159.9 ASTA), Kashmiri chilli (54.1 ASTA), Sanam S-4 (70.4 ASTA) [18].
