Page 36 - FoodFocusThailand No.235 October 2025

SMART PRODUCTION

yields active edible coatings that serve as physical barriers oligosaccharides with bioactive properties such as antioxidant
and gradually release antimicrobial compounds to inhibit and antimicrobial activities. When incorporated into food
bacteria and fungi on food surfaces, thereby extending the systems, these oligosaccharides can significantly improve
shelf life of fruits, vegetables, meat, and seafood without preservation efficacy. Moreover, enzymatic modification is eco-
synthetic chemicals. Additionally, incorporating zinc oxide friendly and offers more precise control over the modification
nanoparticles into SA films can greatly boost antimicrobial outcome than certain chemical methods. As such, it represents
efficacy, while adding nanoclays strengthens the film another promising approach garnering significant attention for
structure and reduces oxygen permeability, slowing oxidative developing biomaterials in the future food industry.
spoilage.
2. Chemical Modification: If physical modification Applications of Sodium Alginate in Extending
resembles mixing materials, chemical modification is akin to Food Shelf Life
“molecular surgery.” Through targeted chemical reactions, Preserving food to keep food fresh, safe, and long-lasting
functional groups on SA molecules—such as hydroxyl (-OH) has always posed a major challenge for both producers
and carboxyl (-COOH) groups—can be modified to confer and consumers. Traditionally, food is wrapped in common
novel properties. One notable example is the grafting of plastics such as polyethylene, an inexpensive material
antioxidant compounds, such as tannic acid (a phenolic that nevertheless contributes to plastic waste and carbon
compound found in tea), directly onto the SA structure. This emissions. Today, with laboratory concepts transitioning into
creates a dual-protection system: an initial physical barrier practical applications, modified SA is entering the food industry
against environmental factors and a secondary chemical to tackle these challenges. Modern research focuses on
protection against oxidative degradation. Additionally, safe, biodegradable alternatives that effectively extend shelf
chemical modification can improve the mechanical strength life. One particularly promising solution is packaging based
of sodium alginate films. For instance, certain compounds on seaweed-derived polysaccharides, especially SA, which
can be introduced to react with SA, forming a more robust uniquely forms thin films, gels, or emulsions for foods coating.
cross-linked network within the polymer structure. The Applying modified sodium alginate coatings to fruits
resulting films exhibit enhanced tear resistance, making and vegetables offers a straightforward and highly effective
them particularly well-suited to coating foods that require preservation approach. For example, sodium alginate films
high flexibility. incorporated with mulberry leaf extract have been used to coat
3. Biological Modification: Enzymes are potent lychees, successfully inhibiting fungal growth and reducing
biological tools for modifying biomolecules. In the case of weight loss, thereby extending their shelf life. Similarly, pears
sodium alginate, various enzymes can modify its structure— coated with sodium alginate films mixed with chlorogenic acid
either by reducing its molecular weight size or by introducing exhibit reduced wilting and enhanced wound healing after
targeted functional changes. For example, alginate lyase harvest, allowing them to stay fresh longer.
can depolymerize sodium alginate into shorter chains called Meat and seafood are highly perishable; therefore, sodium
oligosaccharides. This depolymerization not only reduces the alginate films with antimicrobial properties are an attractive
polymer’s molecular weight but also endows the resulting preservation solution. For example, films made from sodium
alginate and gelatin—chemically modified with extracts from
the opium poppy—have been applied to salmon fillets to
reduce bacterial growth while preserving texture and color
(Figure 2). Additionally, research has demonstrated the use
of multilayer sodium alginate films to coat pork, which not only
helps maintain meat quality but also enables spoilage to be
detected by the naked eye.
Sodium alginate films have also been applied to processed
foods. For example, sodium alginate gels enriched with
turmeric extract have been used to coat pork sausages,
to prevent lipid oxidation, thereby extending shelf life and
improving quality. Similarly, in dairy products such as
cow’s-milk cheese, sodium alginate films enhanced with
antioxidants have proven effective in reducing moisture loss
and slowing oxidative reactions—two primary causes of quality
deterioration in cheese.
Modifying SA demonstrates that food science never
stands still. Researchers have been developing innovative
ways to harness natural resources for safe, effective, and
sustainable preservation. In the future, SA could become
the ultimate “protective shield” of modern foods. Through
physical, chemical, and biological modifications, not only are
its properties enhanced but also new innovations unlocked
that reduce food waste and keep foods fresh and safe longer.
Thus, seaweed-derived SA is poised to play a leading role in
ภาพที่่� 2 การประยุุกต์์ใช้้โซเดีียุมอััลจิิเนต์ในอัุต์สาหกรรมอัาหาร the future of food preservation.
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Figure 2 Applications of Sodium Alginate in the Food Industry for
Preservation
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