What Are Softgel Capsules?
Softgel capsules are a form of encapsulated dosage that seals drugs or extracts within a capsule shell. Due to their excellent sealing properties, softgel capsules can effectively retain volatile components and enhance bioavailability. As a result, they are widely used in the pharmaceutical, health supplement, and functional food industries(Cui, 2003).
Gelatin Softgel Capsules
Gelatin softgel capsules require strict storage conditions. It is recommended to store them at a temperature between 15°C and 30°C with a relative humidity of no more than 50% to maintain the stability of the capsule shell(Marianela, Daniel, & German, 2021).
However, if the storage environment exceeds these temperature and humidity ranges, gelatin is prone to issues such as melting, aging, and cross-linking reactions. In particular, prolonged exposure to temperatures above 40°C can accelerate the hydrolytic cleavage of peptide bonds within gelatin molecules, leading to deformation, adhesion, or even rupture of the capsules(Hakata et al., 1994).
During marine transportation, cargo hold temperatures can reach as high as 60°C, further exacerbating these issues and compromising product quality.
Plant-Based Softgel Capsules
With the growing popularity of plant-based concepts, plant-derived softgel capsules have garnered increasing market attention.
One of the common raw materials for plant-based capsule shells is carrageenan.
Carrageenan is a polysaccharide extracted primarily from red seaweed (algae) and is celebrated for being natural, environmentally friendly, and sustainable.
Compared to gelatin softgel capsules, carrageenan-based capsules have more tolerant storage requirements. While gelatin has a melting point of approximately 28–31°C, the melting point of carrageenan, depending on its concentration, ranges from 50–70°C. This confers superior heat resistance, allowing carrageenan capsules to maintain stability even under higher temperatures(Rather et al., 2022) (AgarGel, 2021). Nevertheless, extreme high-temperature conditions should still be avoided to ensure optimal product quality.
With the increasing adoption of vegetarianism and health-conscious lifestyles, consumer acceptance and demand for plant-based products are rising. Carrageenan, being a natural seaweed-derived product free from animal-sourced ingredients, meets the needs of a broader consumer base and offers distinct advantages in the health supplement and dietary supplement sectors.
Moreover, an increasing number of products are pursuing the “clean label” trend—emphasizing simple ingredients, traceable sources, natural origins, and non-GMO status. In this regard, carrageenan-based softgel capsules offer clear advantages.
References
AgarGel. (2021). Carrageenan. Retrieved March 6, 2025, from https://agargel.com.br/en/carrageenan/
Cui, F. (2003). Pharmaceutics. Beijing: People’s Medical Publishing House.
Hakata, T., Nagae, H., Nakazawa, T., Suzuki, K., & Kurihara, S. (1994). Effect of storage temperature on the physicochemical properties of soft gelatin capsule shells. Chemical and Pharmaceutical Bulletin, 42(7), 1496–1500. https://doi.org/10.1248/cpb.42.1496
Marianela, C., Daniel, A., & German, M. (2021). Gelatin and non-gelatin soft gel capsules: A review. International Journal of Pharmaceutical Excipients, 12(2), 19–29.
Rather, J. A., Wani, T. A., Hussain, P. R., Ahmad, M., & Gani, A. (2022). A comprehensive review on gelatin: Understanding impact of the sources, extraction methods, and modifications on potential packaging applications. Food Packaging and Shelf Life, 34, 100945. https://doi.org/10.1016/j.fpsl.2022.100945
