The Application of Nisin in Functional beverages

As a natural antimicrobial peptide produced by Lactococcus lactis,nisin (nisin) has gradually gained recognition for its application potential in functional beverages, thanks to its safety (approved as a food additive in China and many other countries/regions, with the standard number GB 2760-2024), antimicrobial specificity, and degradability. Functional beverages often contain active ingredients such as probiotics, plant extracts, and vitamins; additionally, some products pursue a healthy positioning of "low sugar" and "preservative-free," making them vulnerable to issues like microbial contamination (e.g., spoilage caused by lactic acid bacteria and bacilli) and compromised stability of active ingredients. Nisin’s properties address these pain points effectively while aligning with consumers’ demand for "natural and safe" food.

In terms of application value, Nisin’s core roles in functional beverages focus on two aspects: microbial control and formula compatibility.

For microbial control,nisin exhibits high-efficiency inhibition against Gram-positive bacteria (G⁺), a feature particularly critical for functional beverages. To enhance health benefits, many functional beverages are fortified with probiotics (e.g., Bifidobacterium animalis and Lactobacillus acidophilus), while common environmental contaminants (e.g., Bacillus cereus and Listeria monocytogenes) are mostly G⁺ bacteria. Nisin can inhibit the growth and reproduction of these harmful bacteria without affecting probiotic activity, preventing problems such as bottle swelling, acid spoilage, and flavor deterioration in beverages. Furthermore, for functional beverages made from plant extracts (e.g., herbal or fruit and vegetable juices), their complex nutrient matrices are prone to contamination by miscellaneous lactic acid bacteria. Nisin achieves antibacterial effects by disrupting bacterial cell membranes (forming transmembrane channels that cause intracellular substance leakage), thereby extending the product’s shelf life.

For formula compatibility, nisin has a wide pH tolerance range (pH 2–9), enabling it to adapt to the acidity of most functional beverages (e.g., fruit-flavored functional beverages with pH 3.0–4.5 and herbal functional beverages with pH around 6.0). It shows no significant antagonism with common functional ingredients such as vitamins (e.g., vitamin C, B-group vitamins), minerals (e.g., potassium, magnesium), and plant polyphenols, thus preserving the beverage’s nutritional structure and active components. Meanwhile, nisin maintains good heat resistance during processing (high stability under pasteurization temperatures), ensuring it remains effective despite sterilization processes. Unlike chemical preservatives (e.g., sodium benzoate), it does not react with beverage components to produce off-flavors, guaranteeing consistent flavor in functional beverages.

However, the application of nisin in functional beverages still faces practical challenges.

First is its limited antimicrobial spectrum: Nisin has weak inhibitory effects on Gram-negative bacteria (G⁻, e.g., Escherichia coli, Salmonella), yeasts, and molds. If functional beverages are contaminated with G⁻ bacteria due to incomplete raw material cleaning or filling environment pollution, Nisin alone cannot fully control microbial risks. Additional preservation technologies (e.g., composite bacteriostats, aseptic filling processes) are required, increasing application costs and process complexity.

Second is the balance between dosage control and cost: The effective addition level of nisin in beverages is typically 0.02–0.1 g/kg. However, if the beverage contains high concentrations of protein (e.g., whey protein functional beverages) or fat (e.g., nut-based functional beverages), these components bind to nisin, reducing its free concentration. This necessitates higher addition levels to achieve antibacterial effects, driving up production costs. Moreover, current production of high-purity nisin relies on microbial fermentation, with high purification costs. Compared to traditional chemical preservatives, nisin lacks price advantages, limiting its large-scale application in mid-to-low-end functional beverages.

Additionally, attention must be paid to the potential risk of sensory impact: Although nisin itself has no obvious off-flavors, in some highly acidic functional beverages (pH < 3.0) or those containing high levels of aldehyde/ketone flavor substances, slight degradation or interaction may occur, producing trace amounts of bitterness or metallic taste that impair the drinking experience. This issue needs to be addressed through formula adjustments (e.g., adding appropriate sweeteners or flavors) or process optimization (e.g., adjusting the timing of Nisin addition to avoid direct contact with high-temperature raw materials).

To further expand nisin’s application in functional beverages, current research and practice are advancing in two directions: composite application and dosage form optimization.

In composite application, one approach is compounding nisin with other natural bacteriostats—for example, combining nisin with plant-derived antibacterial components (e.g., rosemary extract, tea polyphenols) and organic acids (e.g., citric acid, lactic acid). Phenolic substances in plant extracts disrupt the outer membrane of G⁻ bacteria, allowing nisin to enter bacterial cells and exert its effects, thereby expanding the antimicrobial spectrum. Meanwhile, organic acids lower the beverage’s pH, enhancing nisin’s stability and antibacterial activity. This synergistic effect reduces the required addition level of each component, cutting costs and avoiding sensory issues caused by excessive single-component use. Another approach is combining nisin with non-thermal processing technologies such as high-pressure homogenization and pulsed electric field (PEF). Non-thermal technologies destroy microbial cell membranes through physical effects, complementing nisin’s mechanism of action. This not only improves sterilization efficiency but also better preserves active ingredients (e.g., probiotics, vitamins) in functional beverages, aligning with consumer demand for "low-temperature freshness retention."

In dosage form optimization, the core lies in improving nisin’s application performance through microencapsulation technology. Edible wall materials (e.g., maltodextrin, chitosan) are used to encapsulate nisin into microcapsules, which prevents direct binding between nisin and components like protein/fat in beverages, maintaining the concentration of free nisin and reducing addition levels. It also enhances nisin’s stability in extreme environments (e.g., high acidity, high-temperature sterilization) and extends shelf life. Furthermore, microencapsulation enables controlled release of nisin, ensuring continuous antibacterial effects during beverage storage. This technology has been tested on a small scale in dairy-based functional beverages and fruit/vegetable juice functional beverages, yielding promising results.

In summary, nisin has clear application value in functional beverages, particularly for products positioned as "natural, chemical preservative-free, and high in active ingredients." However, its application still requires addressing issues related to antimicrobial spectrum, cost, and sensory impact. With the maturity of composite antibacterial technologies and breakthroughs in dosage form optimization, nisin is expected to become a key enabler for balancing "safe preservation" and "health attributes" in the functional beverage industry. It holds broad application prospects in niche segments such as high-end functional beverages, probiotic beverages, and plant-based functional beverages.