Candelilla wax (CW) extraction and its applications in the food industry
INTRODUCTION
A natural vegetable wax called “candelilla wax” is extracted from the stems and leaves of the Euphorbia antisyphilitica plant. It is a flowering plant in the family Euphorbiaceae and is commonly known as the candelilla plant. Sometimes, candelilla wax is referred to as Euphorbia Cerifera wax on the packaging.
Candelilla plant is cultivated in semi-arid southern U.S and northern Mexico areas. Vargas-Piedra et al. (2020) reported that over 19.1 million hectares are favorable for the farming of candelilla plants. With this property disposition, wax manufacturing and commercialization might continue for at least another half-century.
EXTRACTION METHODS
There are two methods generally used for the extraction of the wax,
1. Extraction with Sulfuric acid (Traditional method)
2. Extraction with Organic acid (Eco-friendly method)
1. Extraction with Sulfuric acid (SA)
In this method, sulfuric acid is used as an extracting agent at an initial concentration of 0.4% in water
The plant material (leaves or stems) is boiled in a stainless-steel pot with sulfuric acid to release the wax
The wax comes out as a grayish foam which is recovered and cooled
The wax is refined by first boiling it in sulfuric acid and then boiling it in water to flush out any unwanted components
Disadvantages
It gives high-impurity wax
This process is dangerous (unsafe)
Produce polluting wastes
Precaution
The sulfuric acid extraction of CW is thought to be hazardous for the personnel involved in it due to the noxious fumes produced and the insecure primary extraction conditions.
2. Extraction with Citric acid (CA)
In this method, citric acid is used as an extracting agent at an initial concentration of 2.4% in water
The plant material (leaves and stems) is immersed in a boiling solution of water and citric acid
A grayish-colored foam comes out on the surface, which is collected and cooled
Refine it to remove any undesirable compounds
Advantages
This technique is safe for the environment and is a good substitute for recovering CW
In extraction operations, it has several technical, environmental, and health benefits, including the use of organic acids (citric acid) and the production of less hazardous steams
PHYSICOCHEMICAL PROPERTIES OF CW WAX
Physical properties
The melting point of CW ranges from 60 to 78 °C, which is similar to that of beeswax. Due to this tendency, combining both waxes produce a harder austenite product
It is odorless, lipophilic, and soluble in many organic solvents, however, insoluble in water
It is brittle, hard, and appears yellowish brown
Chemical properties
The main components of CW are esters, resins, and hydrocarbons, which are produced from free fatty acids and free fatty alcohols
The saponification value (SV) of candelilla wax ranges from 40 to 70 mg KOH/g, depending upon the method of extraction. The saponification value (SV) represents the average fatty acid molecular weight of the sample, which is a measure of fatty acid composition
Candelilla wax shows an iodine number (IN) ranging from 14.4 to 27, which indicates that it has a lower percentage of unsaturated fatty acids. Lower unsaturation level (smaller number of double bonds) increases the oxidative stability of CW
CW shows a relatively low acid value (AV), which ranges from 12.62 to 18.1 mg KOH/g. It shows resistance to hydrolysis of the CW components, making it appropriate for use in a variety of food industry operations
PERMITTED USE OF CW IN THE FOOD INDUSTRY
The Food and Drug Administration (FDA) in the United States has declared the candelilla wax to be generally recognized as safe (GRAS)
Its safety and suitability as a food additive have been examined by international committees, organizations, and advisory groups
CW is used as a food additive, has the E number E-902, and is used as a glazing and surface agent, as well as a binder in chewing gum while following good manufacturing practices (GMPs)
It is not considerably absorbed from the food, and even if it is, its primary components can be integrated into the normal cellular metabolic pathway
Acceptable daily intake (ADI) of CW for humans ranges from 600 to 2400 mg/kg body weight/day.
The Codex Alimentarius sets the permitted levels according to the category, up to 200 mg/kg of food, or following GMPs, and only permits its use in carrying out the specific activities of the carrier, emulsifier, clouding agent, thickening agent, and texturizer
APPLICATIONS
Nowadays CW has become a prospective candidate for utilization in the development of many food formulations. It is appropriate for use in a variety of food applications because of its physicochemical and functional characteristics, with admirable traits. Oleogel formation, edible coatings and films, and candelilla wax-based emulsions are the principal applications of CW.
Here are the two most well-known CW applications currently employed in the food industries.
1. Candelilla wax-based biodegradable packaging (CWBP)
Biopolymers including lipids (oils & waxes), polysaccharides, and proteins, are joined with other essential ingredients to form biodegradable edible films and coatings. Therefore, CW plays a key role in manufacturing biodegradable and bioactive packaging.
Preparation method
The production process and formulation of candelilla wax-based biodegradable packaging (CWBP) determine its physicochemical and functional attributes. Therefore, a variety of ingredients have been used in the formulation of CW-based coatings and films. High temperature and mixing forces are used to manufacture CWBP to ensure that the ingredients are properly emulsified and integrated.
The following steps are involved in the preparation of candelilla wax-based biodegradable packaging.
First, solubilize the structural agent (polysaccharides or proteins) in distilled water at room temperature, followed by heating this solution to over 80 °C.
Add the CW to this solution and stirred at 1000 to 20,500 rpm for 5–10 min to make a homogenized solution
Now, to coat the target fruit or vegetable, immerse it in this homogenized coating solution for a short period, about 30 s.
After that remove the fruit or vegetable from this solution and keep it aside to dry
2. Candelilla wax-based oleogels (CWOs)
Oleogelation has gained significant attention because of its health-related benefits. It is a recent term that described the process of transforming liquid oils into gel-like material. Oleogels are being used as a healthy substitute for saturated and trans-fat in a wide range of food items, including bread, meat, confectionary, and dairy products. This technique involves two ingredients, oil as a continuous liquid phase and gelling or structuring agent. Organic gelling agents with low molecular weight, called oleogelators, are used as gelling agents such as vegetable waxes (candelilla wax, carnauba wax), monoglycerides, and alcohols.
Candelilla wax is used as an oleogelator in oleogels of many oils, but it shows more compatibility with canola. Different concentrations of CW are required to gelatinize different oils. Oleogel of canola with a better texture can be obtained using a 3–5% concentration of CW.
Following procedures can be followed to prepare oleogel, with few modifications.
Take the weighted quantity of oil into a Pyrex glass beaker
Weigh 3–5% (by weight of oil) CW and add it into the beaker containing oil
Put the beaker along with the thermometer on the hot plate and start heating with mild stirring with a stirrer
Heat the mixture until the temperature reached 160℃
Remove the beaker from the hot plate and stir the mixture continuously for 10 min
Cool it at room temperature for overnight to form oleogel. Store it in the refrigerator at 4–5℃ for further use
Conclusion
It is concluded that
The extraction of candelilla wax with citric acid is an eco-friendly technique.
The physicochemical properties of CW depend upon the extraction technique
The use of is generally recognized as safe (GRAS)
It has great potential to be used in the food industry in the formulation of different food products