Page 62 - FoodFocusThailand No.219 June 2024

SMART PRODUCTION

solution in Figure 2), while increasing it in the concentrated
solution (ion concentrated liquid in Figure 2). In practice,
reducing the sodium chloride content to zero is not feasible,
as the fish sauce would lose an excessive amount of its
characteristic flavor substances.
Based on the above-mentioned principles, an industrial-
scale electrodialysis unit has been developed, capable of
reducing the sodium chloride content in 100 liter of fish sauce
per batch, as shown in Figure 3. The unit can remove more
than 40% of sodium chloride and potassium chloride from
fish sauce (from around 1500 milligrams to less than 900
milligrams and from 50 milligrams to less than 30 milligrams,
respectively), while maintaining the natural color, aroma, and
taste of fish sauce, making it acceptable to consumers. This
at 2,000 milligrams per day. However, many consumers still low-sodium and low-potassium fish sauce can be used as
consume more sodium than that recommended, with fish a seasoning product that helps reduce the risk of high blood
sauce being a significant source. Typical fish sauce available pressure in the general population and is also suitable for
in the market contains over 20% sodium chloride (with an patients with kidney disease who cannot consume a large
average of 25-28%). When used as a seasoning or a primary amount of potassium chloride. Such fish sauce contains
ingredient in dipping sauces, sodium intake of consumers more than 9 grams of total nitrogen per liter, equating to 62
correspondingly increases. Therefore, fish sauce is a product grams of total protein per liter, the amount comparable to
that health-conscious consumers and those with health issues that of a regular fish sauce as per the Ministry of Public Health
should avoid. Although there exist low-sodium fish sauces Announcement No. 203. The fish sauce is also free from
that use potassium chloride as a substitute for sodium chloride, pathogenic bacteria and heavy metals.
such products possess some important limitations. Sodium In summary, electrodialysis can be used to produce
chloride cannot be substituted at a higher amount as low-sodium and low-potassium fish sauce while retaining
potassium chloride may impart a bitter taste, making the so- the characteristic aroma and flavor of the product, making it
called ‘low-sodium’ fish sauce unacceptable to consumers. acceptable to consumers. The product is made from
More importantly, such products are unsuitable for patients genuine fish sauce without added flavoring components and
with certain kidney and/or heart diseases (Figure 1). This has can be used as a seasoning to reduce the risk of high blood
led to the need to produce low-sodium (and low-potassium) pressure in the general population and for patients with kidney
fish sauce using other production processes, namely, disease who cannot consume a large amount of potassium
electrodialysis, with the aim to develop a product that exhibits chloride.
unique aroma and flavor acceptable to consumers from
genuine fish sauce without added flavoring agents.

Production of Low-Sodium and Low-Potassium More Information Service Info C007
Fish Sauce by Electrodialysis
Electrodialysis is a separation process that uses an electric
potential difference between an anode and a cathode to drive
ion separation through ion-exchange membranes placed เอกสารอ้างอิง / References
alternately between the electrodes. The process begins by กรุุงเทพธุุรุกิจ (2559) มิิติิใหมิ่การุลดบรุิโภคเค็มิกับอนาคติของสัังคมิไทย
introducing a high-sodium chloride solution (dilute stream) [https://www.bangkokbiznews.com/pr-news/biz2u/219681, เข้าถึึงเมิ่�อ
and a low-sodium chloride solution (concentrated stream) into 13 สัิงหาคมิ พ.ศ. 2565]
the flow channels between the ion-exchange membranes, as สัำานักงานคณะกรุรุมิการุอาหารุและยา (2543) ปรุะกาศกรุะทรุวงสัาธุารุณสัุข
shown in Figure 2. When a direct electric potential difference ฉบับท่� 203 เรุ่�อง นำ�าปลา [http://food.fda.moph.go.th/law/data/announ_
is applied between the electrodes, sodium chloride dissociates moph/P203.pdf, เข้าถึึงเมิ่�อ 13 สัิงหาคมิ พ.ศ. 2565]
into ions. Positively charged ions (Na ) move towards the สัำานักงานคณะกรุรุมิการุอาหารุและยา (2561) ปรุะกาศสัำานักงานคณะกรุรุมิการุ
+
cathode through the cation-exchange membrane (C) and are อาหารุและยา เรุ่�อง คำาชี้่�แจงปรุะกาศกรุะทรุวงสัาธุารุณสัุข ฉบับท่� 392 [http://
blocked by the anion-exchange membrane (A), while food.fda.moph.go.th/law/data/announ_fda/No.392.pdf, เข้าถึึงเมิ่�อ 13
negatively charged ions (Cl ) move towards the anode through สัิงหาคมิ พ.ศ. 2565]
-
the anion-exchange membrane and are blocked by the cation- Chindapan N., Devahastin S., Chiewchan N. (2009) Electrodialysis de
exchange membrane. This results in alternating high and low salination of fish sauce. J. Food Sci. 74, E363-E371.
ion concentrations in each flow channel, reducing the sodium Chindapan N., Devahastin S., Chiewchan N., Sablani S.S. (2011)
chloride (as well as potassium chloride, which is naturally Desalination of fish sauce by electrodialysis: Effect on selected aroma
present in fish sauce) content in the fish sauce (desalted compounds and amino acid compositions. J. Food Sci. 76, S451–S457.

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