Milt is a biological substance that serves a dual purpose as both a fundamental component of aquatic reproduction and a delicacy in various global cuisines. This substance, sometimes referred to as soft roe, is harvested from the male of the species, paralleling the way fish eggs, or hard roe, are collected from the female. Milt is the male gamete, and its distinct texture and composition have made it a highly valued item in many culinary traditions.
Biological Origin and Function
Milt is the seminal fluid produced by male fish, mollusks, and other aquatic animals, composed of the sperm sacs (testes) and the fluid carrying the sperm. The primary biological purpose of milt is reproduction, specifically in species that utilize external fertilization, commonly known as spawning. During spawning, the male releases the milky white fluid into the water column or directly over the eggs deposited by the female.
This reproductive process is often synchronized between the male and female to maximize the probability of successful fertilization. The seminal fluid in the milt provides a medium that nourishes and activates the spermatozoa, enabling them to swim and reach the eggs. The release of milt is controlled by a complex interplay of hormones and is also stimulated by environmental cues and the presence of a female ready to spawn.
The testes are typically a pair of elongated organs located within the body cavity of the male fish, housing the developing sperm. The chemical composition of milt varies by species, but it is primarily water, protein, and a small amount of fat.
Common Culinary Applications
Milt is consumed across numerous cultures and is often considered a delicacy, prized for its subtle, oceanic flavor and distinctive texture. In Japanese cuisine, milt is known as shirako and is sourced from fish like cod (tara), anglerfish (ankÅ), and pufferfish (fugu). Shirako is prepared in many ways, including being served raw as a sushi topping, lightly grilled, or quickly deep-fried as tempura to create a crispy exterior around a creamy center.
The texture of prepared milt is a central aspect of its appeal, frequently described as soft, smooth, and custard-like, often likened to a delicate egg custard. In European traditions, herring milt is a common ingredient, particularly in Russia, where it is known as moloka and is often pickled alongside the rest of the fish. The milt of tuna, called lattume, is also a traditional ingredient in Sicilian cuisine, where it may be grilled, fried, or grated over pasta dishes.
Cod soft roes are a traditional dish in British cuisine, typically prepared by frying them in butter and serving them on toast. The flavor profile is generally mild, slightly sweet, and only faintly fishy, making it versatile enough to pair with simple accompaniments like lemon juice or soy-based sauces.
Nutritional Components
Milt offers a distinct nutritional profile characterized by high protein content and a favorable lipid composition. In various species, the protein content often falls within the range of 13% to 17% of its weight, making it a concentrated source of dietary protein. For example, cod milt typically provides around 13.4 grams of protein per 100-gram serving.
The fat content is notably low, generally less than 3% by weight, which contributes to its status as a lean source of animal protein. A significant portion of this small amount of fat consists of polyunsaturated fatty acids, including Omega-3s, which are recognized for their health benefits.
Milt is also a source of specific micronutrients, including phosphorus and various B vitamins, such as Vitamin B12. The combination of high-quality protein and beneficial fats makes milt an ingredient that provides dense nutrition without a high caloric load. For instance, a 100-gram portion of Pacific cod milt contains approximately 62 kilocalories.