From the very beginning, manufacturers have used animal-based gelatin to make capsules, a $2.4 billion market poised to grow by 9 percent annually.[i] But consumer demand for plant-based solutions is growing exponentially—in just three years, the number of people who identify as vegans in the U.S. has increased by 600 percent.[ii] It’s a stunning development, and brand owners recognize the pressing need to pivot if they wish to capitalize on the growth of softgel capsules in a fast-evolving marketplace.
There are a range of options for formulating vegetarian-friendly soft capsule solutions, including carrageenan and modified starch. Generally speaking, vegan or vegetarian soft capsule shells are commonly composed of a mixture of these two ingredients.
But which plant-based ingredients perform best for formulations while giving consumers that familiar mouthfeel of gelatin? As it turns out, not all plant-based alternatives are created equal. In fact, IFF’s SeaGel® technology may be the key that unlocks optimal clean-label, non-GMO, vegan and vegetarian dietary supplement options.[iii]
When comparing starch and carrageenan capsules, most differences stem from the ratio of carrageenan to starch used in the formula, as well as the type of carrageenan used. Carrageenan capsules generally have a relatively high amount of carrageenan content (>20%) and less starch, while starch capsules generally have a relatively low amount of carrageenan content (<10%) and more starch. Additionally, different types of carrageenan feature different performance attributes. Selecting the right seaweed extract is pivotal to finding the best combination of manufacturing efficiency, consistency and quality. Choosing a less than ideal seaweed extract may seem attractive initially, but can lead to lower manufacturing speed, more leakers and less formulation flexibility, consequently leading to higher costs of goods sold.
SeaGel® technology separates itself from competing vegetarian solutions because of the type of carrageenan used in its manufacture. Thanks to its unique composition, SeaGel® boasts versatility, superiority in soft capsule manufacturing yield and throughput, and improved quality. Let’s examine some of the common challenges associated with plant-based technologies and how SeaGel® technology may be the ideal solution.
Take care with carrageenan
Figure 1: Lambda, kappa and iota carrageenan chemical structures
Carrageenan is a naturally occurring polysaccharide found in red seaweed that can have different physical properties depending on its chemistry (Figure 1). Lambda carrageenan does not gel but is used as a thickener. Kappa carrageenan forms strong, brittle gels compared with iota varieties, which yield soft, elastic gels (Figure 2, left). Typically, carrageenan soft capsules are formed using either kappa, iota, or a blend of the two. However, selection of kappa or iota carrageenan for producing non-animal soft capsules can result in several important limitations (Figure 2, right). Iota carrageenan yields capsule shells that tend to be too soft to withstand mechanical stress during manufacturing and storage of the capsules. Kappa carrageenan may lead to soft capsules that are too brittle and break causing the fill material to leak out.
Figure 2: Behavior of kappa and iota carrageenan water-gels containing 98% water (left); Comparison of film strength and elasticity for kappa and iota carrageenans vs. SeaGel® (right)
Typically, soft capsule producers seek to overcome these limitations by blending the two together, but the resulting blends may still fall prey to size and shape limitations, low fill capacity and other issues. Resulting formulations are either strong and brittle or weak and elastic, eluding the perfect balance of strength and elasticity. And while thermal sealing is possible, it tends to be of a low quality. Blends can also lead to weaker gel-film systems that can’t tolerate large formats—typically less than 14 minims—or complex fills.
Figure 3: Chemical structure of commonly used modified starch
Modified starch soft capsules are another vegetarian alternative to gelatin. They contain mostly modified starch (e.g. based on tapioca or pea starch) with an auxiliary film-forming aid that comprises less than 10 weight-percent carrageenan. This film-forming aid is added to promote shell formation and to ensure quality when forming the capsules. The most common modified starch is hydroxypropyl starch (see Figure 3). This type of modification leads to more stable gel mass when mixing at high temperatures as well as shell stability after manufacturing is complete. This process also increases the overall viscosity of the starch gel system.
While it is used across the industry, manufacturers may discover a few disadvantages in using starch-heavy formulations. Starch soft capsules are not thermally sealed, resulting in reduced production rates. Also, those capsules tend to show higher leakage, which diminishes quality (e.g., upwards of 80 percent yields). Starch capsule shells are also less elastic, which limits capsule size to a very diminutive 14 minims or less—in addition, they possess sticky ribbons that are easily broken, calling for unnecessary troubleshooting along the manufacturing line. Operations can be slowed down even further if clean-up is needed at any point, since starch is notoriously stubborn to clean and difficult to dissolve in water.
Figure 4: Capsule die comparison for standard capsule dies compared to starch-based capsule dies
The lower elasticity of starch-based films requires adjustments to the design of the die roll (Figure 4). For every revolution of the roll, a starch-based formulation may experience 15-25 percent lower output. Additionally, the die roll must be run at a lower speed because of the aforementioned sealing issues. Manufacturers know that time is of the essence—when using starch, overall production speed is only about 60-70 percent of the speed made possible by SeaGel®.
A hybrid can help
IFF’s patented SeaGel® technology offers manufacturers an operationally robust plant-based option that can match the performance of gelatin. It utilizes a proprietary carrageenan chemistry which has been optimized for use in soft capsule applications. To create SeaGel®, carrageenan is purified for use as a dried powder in SeaGel® CAP 101 or further blended with starch to produce ready-to-use SeaGel® pre-blend systems. The former allows for formulation flexibility while the latter provides additional efficiency benefits.
Soft capsule producers stand to benefit from incorporating SeaGel® technology into their formulations for many reasons, including higher production rates of 4+ rpm or more as compared with the roughly 2-rpm limitations of ordinary starch and/or carrageenan formulations. The proprietary blend also enables a wider range of soft capsule shapes and sizes, tolerating larger formats—accommodating 24 minims and higher—and allowing for highly complex and viscous fill materials to be encapsulated. Last but not least, SeaGel® enables improved soft capsule quality that rarely leaks, offering upwards of 98 percent yields.
IFF’s SeaGel® gives manufacturers a plant-based, versatile soft capsule technology that seamlessly addresses the needs of a fast-growing, health-conscious consumer base. And whether a brand is switching from animal-based products or an inferior plant-based source, the results made possible by Seagel® are indisputable.
SeaGel® enables versatile production of non-animal soft capsules utilizing existing equipment with minimal adjustments. With elegant aesthetics and a robust process window, the superior SeaGel® provides optimal soft capsule shell strength and elasticity that is unmatched by alternative systems based on starch, kappa-carrageenan, iota-carrageenan or mixtures thereof.
Compared to alternative plant-based soft capsule technologies, SeaGel® enables soft capsule production at encapsulation rates nearly 1.5 times faster, resulting in yields that are more than 25 percent higher on the very same equipment. For manufacturers and brand owners looking to achieve outstanding quality, superior sealing performance and reduced leakage in their vegetarian soft capsules—all while guaranteeing quicker disintegration—SeaGel® represents a leap forward in dietary supplement manufacturing that can’t be overlooked.
Michael Baumann, Global Strategic Marketing Manager, Dietary Supplements; Benjamin Roscoe, Application Development & Innovation Manager; IFF (formerly DuPont Nutrition & Biosciences)
[i] GLOBAL CAPSULES MARKET, Opportunity Analysis and Industry Forecast, 2017-2025, Allied Market Research
[ii] January 2018: https://foodrevolution.org/blog/vegan-statistics-global/
[iii]Regional regulations may restrict the use of certain products in dietary supplements or different terminology definitions may apply. Please contact us for further information.