In the depths of the ocean lies a remarkable yet often overlooked marine resource. Known for their gelatinous texture, sea cucumbers have long been prized in some cultures, but recent scientific research is now revealing their potential health benefits. A remarkable discovery has emerged from the Faculty of Applied Sciences at the University of Sri Jayewardenepura, where a dedicated research team has uncovered the significant nutritional and collagen benefits of the sea cucumber known 
as the Lollyfish (Scientific name: Holothuria atra). The research team, led by Dr. Varuni Gunathilake, alongside researchers Nipuna Deelaka Wimalagunarathna and Nishani Jayanika Jayathilake from the Department of Zoology, with co-investigator Prof. Isuru Wijesekara from the Department of Food Science and Technology, embarked on this research project with financial support from the University Grant (Grant Number: ASP/01/RE/SCI/2021/41).This significant finding sheds new light on this marine species, which is currently underutilised, revealing its potential as a valuable resource for health and wellness.
Being an island nation, Sri Lanka is well recognised for its exceptional biological diversity which is untapped and unexplored. The marine ecosystem of Sri Lanka is rich with an enormous number of “animals without backbones” or invertebrate species, including sea cucumbers. In many Asian cultures, they are considered a delicacy, often featured in soups, stews, and other dishes due to unique texture. It is believed that sea cucumbers do not contain any specific flavour and, therefore, can be well combined with any additional flavours. Beyond their role as a food source, sea cucumbers are believed to offer health benefits, such as boosting immunity, improving joint health, and promoting skin healing. Sea cucumbers are also considered good sources of collagen, which is a protein used in many pharmaceutical and industrial applications. Marine collagen is often considered superior to mammalian collagen due to its higher bioavailability, more environmentally friendly and poses a lower risk of contamination. Its neutral taste and hypoallergenic properties make it versatile and safer for a wider range of users.
Amongst several species of sea cucumbers Holothuria atra or lollyfishes, has long been consumed in many regions of the world. However, according to the previous literature, it is considered a low-value species, in Sri Lanka. Under these circumstances, we aimed to investigate the full nutritional profile of jellyfish and obtain collagen.
The present research was carried out in two phases; 1) to investigate the nutritional profile of lollyfish and 2) to extract collagen protein from this and its characterisation. Live specimens of lollyfish were obtained from Mannar, Sri Lanka, and brought to the laboratory at the Department of Zoology, USJ for further analysis. The nutritional composition was examined, starting with tests for moisture, ash, protein, fat, and carbohydrate content using established food analysis methods. The moisture and ash content was calculated. Protein levels were measured using a chemical process that determined nitrogen content, which was then converted into a protein percentage. Fat and carbohydrate contents were investigated using standard methods.
For more advanced nutritional analysis, the fat composition, including healthy fats like EPA (Eicosapentaenoic Acid)and DHA (Docosahexaenoic Acid), which are two essential long-chain omega-3 fatty acids primarily found in fish and other marine sources, were tested. These fatty acids play crucial roles in human health and are known for their anti-inflammatory, cardiovascular, and brain-supporting benefits. Vitamin A and C levels were measured, and essential minerals such as calcium, magnesium, potassium, sodium, zinc, and iron were analysed using mass spectrometry.
In the second phase, collagen was then extracted from the sea cucumber’s body wall through a detailed process involving washing, soaking in acids, and separation. The extracted collagen was analysed for its properties, including moisture content, pH levels, and fibre structure, which was observed under Scanning Electron Microscope.
Our results were fascinating. The moisture content of lollyfish was 83.2 percent , similar to other sea cucumber species, indicating its high water content. The ash content, reflecting mineral deposits, was relatively low at 2.5 percent . The protein content was 10.2 percent , making lollyfish a good source of protein. The study also found low levels of crude fibre (0.2 percent ) and fat (2.0 percent ). The carbohydrate content was 2.1 percent , suggesting that they are a good energy source, with an energy value of 67 kcal per 100 g. These findings indicate that this species should not be ignored concerning its nutritional components.
The analysis further showed that lollyfish contained saturated fats, monounsaturated fats, and polyunsaturated fats, with saturated fats being the most dominant. This is consistent with previous research on other sea cucumber species. The study also recorded a low amount of the beneficial fat, EPA, and did not detect DHA, which aligns with findings in other sea cucumber species.
Additionally, the analysis found no detectable amounts of vitamins A and C in lollyfish, though other species in the same genus, like H. scabra, have been found to contain vitamin C. The mineral content of lollyfish was primarily sodium, followed by calcium, magnesium, potassium, and trace amounts of other minerals like zinc, iron, and copper
Collagen from lollyfish was a white, cotton-like substance, yielding 0.95 percent of the dry weight. It was further confirmed with advanced physical and chemical tests. It had a moisture content of 7.246 percent , and its pH was measured at 3.95, which is within the ideal range for commercial collagen, particularly in cosmetics.
The collagen’s structure was confirmed using a technique called Fourier Transform Infrared Spectroscopy or FTIR, which helps to ensure that the collagen extracted from lollyfish is of high quality and suitable for various applications.
The UV-Vis spectrophotometric analysis was used to identify the type and purity of collagen Accordingly, maximum absorbance at 232 nm was observed, indicating the presence of type 1 collagen.
The Scanning Electron Microscopy images of the collagen from lollyfish revealed a structure of irregular, dense, and pleated fibril networks with a loose and porous appearance, which matches previous descriptions of collagen structure.
This study is the first to analyse the nutritional content and collagen of the lollyfish from the Northwest coast of Sri Lanka. Lollyfish although less valued than fishes, are a treasure trove of essential nutrients and pure collagen, offering untapped potential for various industries. Their rich nutritional profile further confirmed them as an excellent dietary resource, while their high-quality collagen holds significant promise for applications in the health, beauty, and pharmaceutical sectors. As the demand for natural and sustainable ingredients continues to rise, lollyfish stands out as a powerful, eco-friendly solution that could revolutionise multiple industries. Applying their potential values in medicine and health, not only promotes better wellbeing but also supports sustainable practices, making lollyfish an invaluable resource that deserves greater attention and utilisation. We acknowledge the University of Sri Jayewardenepura research grant (ASP/01/RE/SCI/2021/41), for the financial support.
Written by:
Dr. Varuni Gunathilake, PhD
Principal Investigator Department of Zoology
University of Sri Jayewardenepura
Research Team from the University of Sri Jayewardenepura:
Nipuna Deelaka, Department of Zoology
Nishani Jayanika, Department of Zoology
Prof Isuru Wijesekara, Department of Food Science and Technology
Dr Varuni Gunathilake, Department of Zoology
