IMG223 Animal based product- Fish Emulsion

         

               When I was a kid, my mom loves to cook me fish for my daily meal, steam fish, fried fish , curry fish, etc because she afraid that I don’t have enough nutrients and protein for growth. However, since I had a bad experience of choking a fish bone, eating fish seems to be a nightmare to me. From that time onwards, my mom had changed her mind, she bought me FISH EMULSION instead! First of all, let me tell you where is fish emulsion comes from? The answer is from FISH OIL, of course!

     This was the fish emulsion I had during my kids’ time. It came in two flavors, orange and original flavors. Their nutritional content is about the same, just that orange flavor is fortified with calcium.

          Fish oil is extracted from the tissue of oily fish such as tuna, herring, cod and other deep-sea oily fish species. Usually, pelagic fish is used as they have higher oil content abundantly deposited underneath their skin suitable to be used for commercial production of fish oil emulsion. It is rich in omega-3 fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) but does not have much vitamin A or D. Moreover, marine and freshwater fish oil emulsion vary in contents of arachidonic acid, EPA and DHA. Interestingly, studies have shown that marine fish emulsion contains higher DHA than fresh water fish emulsion. Both EPA and DHA have been clinically proven to be able to reduce inflammatory in the body.

          However, fish oil palatability can present a problem where it has a strong fishy smells which might not being widely accepted. Therefore, emulsions can be used as delivery systems for omega-3 fatty acids into functional food and beverage products. In other words, fish oil emulsion allows for the production of a pleasant tasting yet omega-3 rich product and may also enhance the digestion and absorption of the fatty acids. On the other hand, fish oil emulsion has also been widely used as a health supplement as it is rich in omega-3 polyunsaturated fatty acid. This can significantly improve clinical therapy, especially in chronic hyper-inflammatory diseases. Flow chart for fish emulsion as shown below:

          Fish emulsion can exist in several forms such as nanoemulsions, microemulsions or primary oil emulsion depending on the size of the lipid particles dispersed. Moreover, fish emulsion can be produced using nanoencapsulation or microencapsulation technology as both are considered as effective encapsulation techniques. Under these techniques, fish lipids can be incorporated into an aqueous phase to achieve improved dispersion in the food systems, to get protection against the deterioration or degradation, and finally to enhance their bioavailability.

Fish emulsion has smaller oil droplets compare to fish oil, easier for absorption in the digestive system.

           Generally, either high energy homogenization or low-energy homogenization could be used to form fish emulsions. Fish oil emulsion are generally prepared by high-energy methods (e.g., high pressure homogenization, ultrasonic homogenizer). However, the high-energy emulsification methods may impact the chemical stability of polyunsaturated fatty acid enriched fish-oil. However, this problem can be solved by addition of food additives such as emulsifiers. As for low-energy methods (e.g., spontaneous emulsification and phase inversion temperature emulsification), it seems to be more promising method for the production of non food grade emulsion. Although it involves simple equipment, low manufacturing costs, mild conditions to form an emulsion, but several issues has been raised. Mainly due to health concerns associated with using food grade synthetic surfactants. Surfactants are commonly used to stabilize nanoemulsion by adsorbing to droplet surface and protecting them from aggregation and separation. However, low energy method requires the use of high amount of synthetic surfactants. Moreover, natural biopolymer based emulsifiers (polysaccharide & proteins) cannot be used to form nanoemulsion under low energy method but high-energy method can do so.

Different emulsifying system used for fish emulsion processing under high-energy method.

                                

Lab scale production of cod liver oil emulsion.

        Firstly, the processing for fish emulsion begins by mixing pure fish oil together with emulsifier in an aqueous solution using a vacuum homogenizer (3500-4500 rpm for 40-45 min) to produce a coarse water in oil emulsion, followed by high pressure homogenization under 5000 psi for 40-45 min. Make sure that good quality fish oil is used as they contain highest amount of bioactive components EPA and DHA!  The homogenizer breaks the oil into tiny droplets forming an emulsion. The droplets are more than 100 times smaller than the diameter of a human hair. In this step, it is important to ensure the well mixing of both mixtures as we do not want large globules or clumps to form due to agglomeration. Homogenization is an important step as it breaks down the oil into fine lipid droplets and prevents the separation occur in water in oil emulsion. In short, it stabilize the emulsion.

            Protein can act as an emulsifier which spontaneously forming interfacial membrane around the fish oil droplets. For examples, whey protein, casein or albumin have been used as emulsifiers for fish oil. This interfacial membrane can be used as protective barrier which inhibit lipid oxidation by decreasing the interactions between the omega-3 and transition metals, such as ferum and copper, in the aqueous phase. Apart from that, Catechin, caffeic acid, ferulic acid, and tannic acid also showed preventive effect on lipid oxidation in fish oil-in-water emulsion. Besides, this protective barrier can also slows down the escape of volatile compounds in the fish oil droplets, which can cause a fishy taste and smell to the food products and also helps to protect the oil from in contact with oxygen, retards oxidative rancidity.

      Once the fish oil emulsion has formed, 0.1N NaOH is added in order to adjust the final pH of emulsion to pH > 8.8. According to research, the addition of whey protein to fish oil emulsions at high pH can help to create stable emulsions with up to 70% fish oil. It is an optional to add in any active ingredients, coloring, preservatives or flavoring compound follow by mixing before passing through filtration membrane. Last but not least, heat sterilization is necessary to eliminate pathogenic bacteria to a safe level.

           In summary, fish emulsion has brought a lot of benefits in the food product development by scientists and food technologists. It has been widely applicable in various product from pharmaceutical, to clinical, and even pastry industry! Moreover, it is one of a good way to preserve the omega-3 fatty acids from fish oil in the emulsion form and incorporated to various food product.

With fish oil emulsion, our body now received 3 times more nutrients in one tablespoon! Less is more!!!

                                  Click the link below shows a video that fish oil emulsion is

                                          now added into ice-cream production which  

                                         believes can increase the creaminess texture!

                                                       Testing Fish Oil in Ice-cream

References:

Science Learning Hub. (2009, July 29). Retrieved April 18, 2018, from Science Learning Hub: https://www.sciencelearn.org.nz/resources/1513-testing-fish-oil-in-ice-cream

Somprasong, S., Luxsana, D., & Stephan, T. D. (2009). Method for the preparation of secondary emulsions of fish oil in water. Journal of Metals, Materials and Minerals, 19(1), 25-28.