Sea grapes, also known as green caviar, are an edible seaweed recognized for their unique appearance, resembling miniature bunches of green grapes. This marine delicacy is popular in the culinary traditions of coastal regions, particularly across Southeast Asia, Oceania, and East Asia, valued for its texture and flavor.
Biological Characteristics and Natural Habitat
Sea grapes, scientifically classified as Caulerpa lentillifera, are a species of ulvophyte green algae. They are a type of macroalgae, characterized by a siphonous structure that acts as a single, large cell containing multiple nuclei. They can grow up to 30 centimeters in length.
Sea grapes are notable for their tiny, spherical, translucent beads, 0.1-0.2 centimeters in diameter. These beads pack tightly along vertical stems, often forming a dense, sausage-like shape 2 to 10 centimeters long. Each “grape” attaches to its stalk with a distinct constriction. Their colors can vary from bright green to bluish or olive green.
Sea grapes thrive in coastal regions of the Asia-Pacific and Indo-Pacific. They are found on rocks and coral rubble in shallow, calm waters like sandy lagoons and reef flats. Cultivation, which began commercially in the Philippines in the 1950s and later in Japan, requires consistent salinity (30-35 parts per thousand), as they are sensitive to changes in water saltiness.
Nutritional Composition and Health Properties
Sea grapes have a rich nutritional profile, containing vitamins, minerals, and other beneficial compounds. They are a source of vitamins A, C, E, and K, and minerals such as iodine, calcium, magnesium, potassium, iron, and zinc.
They contain protein, dietary fiber, and omega-3 fatty acids. They are low in calories (approximately 20-30 calories per serving or 35.7 calories per cup). This combination of low calories and high fiber can contribute to fullness, aiding in weight management.
Sea grapes offer several health advantages. Their iodine content supports thyroid function, important for metabolism regulation. Calcium, protein, and omega-3 fatty acids contribute to bone and joint health. Omega-3 fatty acids benefit heart health, helping to lower blood pressure and cholesterol.
Sea grapes contain antioxidants, which protect cells from damage. Vitamins and minerals support the immune system. Their hydrating properties and antioxidant content (vitamins A, C, and E) promote skin health and elasticity. Fiber aids digestive health, promoting regular bowel movements. Due to these attributes, sea grapes are sometimes called “longevity seaweed,” particularly in Okinawa, Japan.
Culinary Applications and Consumption
Sea grapes are appreciated for their distinctive taste and unique texture. They offer a fresh, slightly salty, briny flavor, often described as “like the ocean.” Their crisp texture and satisfying “pop” sensation when bitten earned them the nickname “green caviar.”
They are almost always consumed raw to preserve their unique texture. They are often incorporated into salads, enhancing the dish with their popping texture and fresh taste. They also garnish sashimi and top rice bowls and noodle dishes. Other uses include sushi, soups, smoothies, or salsas.
Before serving, sea grapes are rinsed in clean, cool water. This removes any slight fishy odor and excess salt, ensuring a clean flavor. They are paired with dipping sauces like soy sauce or vinegar to complement their natural brininess. Some traditional preparations serve them with chopped shallots and fresh tomatoes. Avoid cooking sea grapes with high heat, as this can compromise their crisp, popping texture.