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Application of Methyl CelluloseHydroxypropyl Methyl Cellulose Substituting Gum Arabic in Emulsified Flavor

Views: 0     Author: Site Editor     Publish Time: 2023-06-05      Origin: Site

Abstract: Gum Arabic is considered to be the most suitable colloid in diluting oil-in-water system. A typical application example is to use gum arabic to make citrus essential oils into water-dispersible emulsions, and then use them in citrus-flavored soft drinks. But for years, a steady supply of gum arabic has not been guaranteed due to unpredictable climate fluctuations and political unrest in Africa, a major gum arabic producing region. This paper studies the application of methylcellulose and hydroxypropylmethylcellulose in 8% and 12% concentrated orange oil emulsions to replace 20% gum arabic, and the results show that the dosage can be significantly reduced, and it can be used in 4 Obtain equivalent or better visual and viscosity stability under room temperature storage for more than one month. This concentrated emulsion is very effective in cold-fill beverages (most soft drinks).

Key words:methyl cellulose; hydroxypropyl methyl cellulose; emulsified essence; beverage

1. Application of gum arabic in emulsified essence

Many beverages including carbonated soft drinks, non-carbonated juice/fruit flavored drinks, sports drinks, and fruit juices use essential oils to give the beverage the proper flavor. Sometimes it is also necessary to give the beverage certain appearance characteristics. A typical beverage consists of an aqueous phase of cedar and an emulsion containing concentrated essential oils (5% to 25%). In addition to essential oils, this emulsion usually contains water, preservatives, acid regulators, and thickeners (colloids) to ensure a uniform and stable emulsion. This stabilization also includes preventing oil-water separation of the emulsion in the final feedstock. Not all stabilizers can achieve this effect. Because this stabilizer is required to be effective at the very low pH of the emulsion and at the relatively high pH of the beverage. In addition, this stabilizer/emulsifier needs to ensure the turbidity of the beverage to reflect the appearance of natural fruit beverages. This turbidity is due to the uniform distribution of the essential oil droplets in the aqueous phase of the beverage. However, due to the difference between the density of essential oils (<0.99/mL) and the density of the final beverage (>1.00s/mL), there is an incompatibility between the two, so there is oil-water separation in the beverage or there is a liquid at the bottleneck. The oil ring appears. The stability of concentrated essential oils needs to be guaranteed for more than 6 months. However, due to the oxidation problem of essential oils, generally speaking, the industry expects that the use period of concentrated essential oils can be within 1-2. Once the concentrated essential oil is used in a beverage, the shelf life of the beverage needs to be 12 months or more, that is, there is no oil ring phenomenon in the beverage bottle or the beverage at the bottom of the container becomes clear.

Typically, concentrated fragrance emulsions are added to water at room temperature under "cold processing" conditions, such as carbonated beverages, because their pH is very low (<3.0) which is not conducive to microbial growth. However, some fruit juice drinks with low sugar content or low solid content have a high pH (>3.5), and the beverage must be pasteurized to achieve microbial stability during the shelf life. Therefore, concentrated essential oil emulsions should be able to accommodate cold and hot processing of beverages.

Gum Arabic has been used in the emulsifying flavor industry for a long time, which is determined by its unique chemical structure and emulsifying properties. Gum Arabic is a water-soluble polysaccharide with an average molecular weight of 350,000. Of all common commercial gums (unhydrolyzed), the aqueous solution of gum arabic has the lowest viscosity, apparently due to its highly branched structure and globular (not easily extensible) morphology. The viscosity of 25% gum arabic solution is about 90-140cP, the pH of the solution is generally 4-5, and the properties of the gum solution are relatively stable in the range of 2-10.

Gum Arabic is composed of about 98% polysaccharide and 2% protein. It is a polysaccharide high polymer with a complex molecular structure with arabinogalactan as the main and multi-branched chains. Gum Arabic is considered the most suitable colloid for diluting oil-in-water systems. A typical application example is to use gum arabic to make citrus essential oils into water-dispersible emulsions, and then use them in citrus-flavored soft drinks.

Over the years, the price of gum arabic in the international market has soared and remained high, and the situation is very grim. A steady supply of gum arabic is not guaranteed due to unpredictable climate fluctuations and political unrest in Africa, the main production region of gum arabic. Therefore many studies and products from many colloid and starch companies have been devoted to the partial or total replacement of gum arabic. Maltodextrin and modified starch have been used as substitutes for gum arabic in spray-dried emulsions (Trubiano, 1988).

2. Chemical structure of methylcellulose/hydroxypropylmethylcellulose

Cellulose is the most abundant natural polymer in nature. It is a linear polymer compound connected by D-glucose through β-(1-4) glycosidic bonds. The degree of polymerization of cellulose can reach 18,000, and the molecular weight can reach several million. Cellulose can be produced from wood pulp or cotton, which itself is not soluble in water, but it is strengthened with alkali, etherified with methylene chloride and propylene oxide, washed with water, and dried to obtain water-soluble methyl cellulose ( Methylcellulose, MC) and hydroxypropyl methylcellulose (Hydroxypropyl Methyleellulose, HPMC), that is, methoxy and hydroxypropoxy are used to replace the hydroxyl groups on the C2, C3 and C6 positions of glucose to form nonionic cellulose ethers.

Methylcellulose/Hydroxypropylmethylcellulose has the functions of water retention, thickening, emulsification, film formation and surface activity, and has been used in the food industry for 80 years. In 2007, it was registered as a food additive by Dow Chemical in China. Methyl cellulose/hydroxypropyl methyl cellulose can reduce the surface and interfacial tension (providing a surface tension in the range of 42-64mN/m), and can increase the viscosity of the liquid phase, so it has the effect of emulsification. Kolanowski (2004) used methyl cellulose for the microencapsulation of fish oil, and achieved very good emulsification and embedding effects on fish oil.

The main goal of this study is to evaluate the application of methylcellulose/hydroxypropyl methylcellulose products in concentrated emulsified essential oils, so as to judge whether they can replace gum arabic in related beverages.

3. Experimental method

3.1 Methyl cellulose/hydroxypropyl methyl cellulose used in essential oil emulsion

Here are the recipes and steps for preparing concentrated essential oil emulsions:

Recipe I

Orange Oil: 8 or 12%

Rosin glyceride: 5%

Citric acid: 0.15%

Sodium benzoate: 0.02%

Gum Arabic: 20%

Water: up to 100%


1. Dissolve rosin glycerides in orange oil in a plastic beaker;

2. Dry mix citric acid, sodium benzoate and colloid;

3. Add the dry mixture to the oil and stir with a spoon to form a homogeneous slurry;

4. Add 18°C to the above slurry, and stir evenly with a Silverson mixer at a speed of 1200rpm;

5. Measuring the viscosity of the above-mentioned emulsion precursor;

6. The emulsion precursor was homogenized at 3000psi with a Microfluidics homogenizer;

7. Measure the viscosity of the homogenized emulsion, transfer it to a glass jar, and store it at room temperature. Observe the stability of the emulsion and take pictures at regular intervals;

8. Determine final viscosity, pH and take pictures.

KIMA CHEMICAL CO., LTD's food grade METHOCELTMF_5 (hydroxypropyl methylcellulose), F0 (hydroxypropyl methylcellulose), A15 (methylcellulose) and SGAl50 (methylcellulose) and pharmaceutical grade K3 (Hydroxypropyl methylcellulose is used to prepare 8% or 12% orange oil emulsion respectively. The amount of METHOCEL is as close as possible to the viscosity of the reference sample (15% or 20% gum arabic, relevant to the oil content) ).

3.2 Preparation of final drink

Recipe II

Sucrose: 19.65%

Citric acid: 0.15%

Emulsion (Formulation I): 0.1%

Sodium benzoate: 0.1%

Color: as required

80% water


1. All the ingredients in formula II (emulsion made from formula 1) are mixed at room temperature;

2. Add the emulsion made by Formula I and stir with a spoon for 1 min;

3. Add the above mixture into a 300g capped glass jar, store at room temperature, observe the beverage stability and take pictures.

Note: In order to simulate the hot filling of beverages, the preparation of beverages is carried out at 80 °C. Stirring is done by Silverson at 2000r/min.

3.2 Turbidity determination

The stability of the final beverage (retention of turbidity) was characterized by measuring turbidity (% Haze and, or mg/L solids) with a Nippon Senshoku COH-300A Color-Oil-Haze tester. Beverage was added to the sample chamber of 80mL, and the transmittance and scattering rate of light were measured.

4. Experimental results and discussion

Initial experiments found that all methylcellulose and hydroxypropyl methylcellulose can stabilize 12% concentrated essential oil emulsions within 7 days, so further experiments were to prepare 8% and 12% concentrated essential oil emulsions To ensure stability for a longer period of time.

For the 12% emulsion, the control sample experienced an increase in viscosity during storage, while METHOCEL E5, FS0 and SGA150 had a significant decrease in viscosity at the corresponding viscosities, indicating emulsion instability. METHOCEL A15 and K3 showed only a slight viscosity drop, indicating their stability.

The final pH of all the 12% concentrated fragrance emulsions added by MEHTOCEL is between 3.2 and 3.4. Clearly, pH plays a very important role in the stability of emulsions. The lower the pH, the greater the effect on the stability of the emulsion. METHOCELA15 and K3 showed stability at low pH. The final pH of the emulsion prepared with 20% gum arabic was about 4.2. Therefore, it can be considered that gum arabic is a stabilizer used in a relatively high pH environment.

The METHOCEL E5, F50 and SCA150 emulsions developed yellowing and oil rings, the results of which can correspond to a significant drop in viscosity in Table 1. The control sample with 20% gum arabic showed an increase in viscosity, yellowing and oil rings, also indicating instability. However, as long as the viscosity of METHOCEL A15 and K3 emulsions drop slightly, their stability is superior to that of gum arabic.

For the 8% concentrated essential oil emulsion, the emulsion prepared with 15% gum arabic had the same viscosity change as the emulsion prepared with 20% gum arabic. The emulsion prepared by 5% MEHTOCEL K3 is very stable. The viscosity of all emulsions decreased during the four-month storage, with METHOCEL E5 decreasing less. The pH of all 8% concentrated essential oil emulsions was similar to that of the 12% concentrated essential oil in Table 1 after 4 months of storage. 2.75% METHOCEL Al5 and 5% METHOCEL K3 have excellent stability. Samples prepared from gum arabic showed a slight loss of yellow color but were relatively stable. Emulsions using MEHTOCEL ES and F50 have obvious yellowing and oil rings, while emulsions prepared by METHOCEL SCA150 are stable and have no yellowing and oil rings, but there is a slight oil-water separation at the bottom of the bottle that cannot be observed in the photos.

All 12% concentrated essential oil emulsions were made into beverages. Use 20C cold filling. As-prepared materials all had acceptable turbidity with no oil rings present. Using 2.75% METHOCEL F50, 4. 25% METHOCEL A15 or 7% METHOCEL K3 has excellent turbidity stability compared with gum arabic. However, beverages prepared with 1.8% METHOCEL SCA150 and 7% METHOCEL ES appeared in a clear state and showed instability.

METHOCEL Al5 and K3 showed the best characteristics of replacing gum arabic after 4 months storage of emulsion and 7 months of beverage storage. All METHOCEL prepared beverages using hot fill (80°C) exhibited unacceptable instability due to sedimentation of METHOCEL during heat treatment.


The application of methylcellulose and hydroxypropylmethylcellulose in 8% and 12% concentrated orange oil emulsions to replace 20% gum arabic can significantly reduce the dosage, and can be stored at room temperature for more than 4 months comparable or better visual and viscosity stability. The use of this concentrated emulsion is very effective in cold-fill beverages (most soft drinks), but not in hot-fill beverage products.