What is a Tomatillo and How It's Different from a Tomato?

Where does the tomatillo comes from?

Mexican husk tomatoes (Physalis philadelphica and Physalis ixocarpa) are well known in Mexico as tomatillos or green tomatoes. Tomatillos come from warm climates. They are native to Mexico and Central America, where people used them before the arrival of Europeans. The name tomatillo comes from the Nahuatl language and means "drop of fat" (tomohuac - fat, atl - water). The name Physalis comes from Greek and means bladder, bellows, or bubble. The name comes from the layer of natural wax that protects the tomatillo fruit.

Tomatillos were cultivated long before tomatoes and were a significant part of the diet in pre-Columbian times. Archaeological finds from the Tehuacán Valley show evidence of their use. Today, tomatillos are still prevalent in South American countries, where they are enjoyed in many traditional dishes. However, they have also spread around the world, becoming a popular ingredient in many cuisines.

Tomatillos are related to the cape gooseberries and the Chinese lantern plant, producing paper-thin husk to protect its tasty fruit.

What does a tomatillo plant look like?

Stalk

The stem of tomatillo plants is strongly branched and woody at the base, reaching a height of over 100 cm. Traditional Mexican varieties such as Rendidora, Toma Verde, Rio Grande Verde (varieties with bright green fruit), and Purple (a variety with purple fruit) can grow up to 150-200 cm in height. Due to the vigorous growth and large mass of fruits that cover the plant during full fruiting, it is essential to provide supports to prevent the shoots from breaking off when growing tomatillo plants.

Leaves

Tomatillo leaves serve a practical purpose while also adding a touch of beauty to any garden or dish. They have an elegant, oval shape with pointed tips and a rippling edge that creates a unique visual texture. Delicate, almost invisible hairs cover the leaves, giving them a velvety appearance similar to tomato leaves. Fully developed tomatillo leaves are compact yet striking, measuring 6 cm long and 3 cm wide.

Flowers

The tomatillo's flowers are a wonder to behold. These stunning yellow blooms are short-stalked and have a diameter of 8-15 mm. They grow singly in the branches of shoots and leaf axils from June to October. The flowers' unique shape and intricate composition are a true marvel of nature. They consist of five sepals, one pistil, and five stamens, all working in perfect harmony to create a stunning display. Each of the five perianth petals has a bold purple spot at the base, adding a splash of color to this already vibrant plant.

The papery husk surrounding the tomatillo fruit

As the tomatillos grow, the calyx of the tomatillos enlarges and eventually surrounds the fruit inside. Such an overgrown calyx is called a bellows by botanists.

The fruits of the tomatillo plant

The edible part of the tomatillo is the juicy berry. The berry is smooth and shiny, covered with a 0.5 mm layer of sticky coating. Characterized by high morphological variability, the fruit varies in color (green, orange, or purple) and weight (20-60 g), depending on the variety. Inside the fruit, there is spongy flesh with a specific sweet and sour taste. The fruit's glassy, aromatic, the gooseberry-like pulp has a color from pale yellow to greenish.

What is the difference between a tomatillo and a tomato?

The origins of the tomato and tomatillo are the same, but they are grown worldwide today. Although tomatillo fruit resembles green tomatoes at first glance, there are many differences between these species of the nightshade family. Due to the recent popularity of the Physalis, its green fruits are often more confused with unripe tomatoes.

Tomatoes change color during ripening, while tomatillos retain a bright green color. There are also varieties of tomatillos with yellow or purple colors that also change color. However, they are less commonly grown than traditional green tomatillos. The shape of the Physalis fruit is always round, while tomatoes can produce oblong, kidney-shaped, ball, or heart-shaped fruits. Also, the size and weight of tomatillo fruit are constant - from 0.2 to 0.5 g.

The green fruit of tomatillo has a crunchy texture and a slightly sour taste and is less juicy than tomato fruits.

Unlike ripe tomato, the green tomato has toxic solanine. Therefore, before consumption, tomatoes must be subjected to heat treatment. Unlike tomatoes, fully ripe tomatillos are not poisonous but contain trace amounts of alkaloids.

Differences	Tomato	Tomatillo
Botanical name	Solanum Lycopersicum	Physalis philadelphica, Physalis ixocarpa
Aztec name	xitomatl	tomatl
Height	From 150 cm to several meters	Up to 2 m
Papery husk	Lack	Present, as the fruit ripens, it breaks
Fruit size	Variable	Consistent
Fruit shape	Round, oblong, heart-shaped	Round
Wax covering the fruit	Lack	Present
The number of cells in the fruit	3 - 8	2
Stalk	Branches poorly, usually there is a main leading shoot	Branches out forked (dichotomously)
The juiciness of the fruit	Delicate, juicy, easily damaged, during ripening they soften	Dense, crunchy, they do not soften as they mature
Color change as the fruit ripens	Turns red when ripening	Green tomatillo varieties do not change color
Use in the kitchen	Italian	Latin American
Toxicity	The whole plant is toxic, also immature fruits contain toxic tomatine and solanine	The whole plant, there are small amounts of alkaloids in the fruit

Is a tomatillo toxic / poisonous?

A distinctive feature of nightshade family plants is that they contain poisonous glycoalkaloids, saponins, and lectins, and for this reason, some people should avoid their consumption. The alkaloids found in nightshade vegetables are solanine, tomatine, and capsaicin. They are found mainly in the green parts of plants. Toxic natural pesticides are also produced by Physalis ixocarpa.

Tomatillo fruit should be avoided by people sensitive to lectins and suffering from autoimmune diseases, e.g., Hashimoto's disease. For this reason, eating tomatillos can be poisonous.
Tomatillo glycoalkaloids are natural pesticides that plants produce to repel insects and animals. Glycoalkaloids are also found throughout the tomatillo plant. Fortunately, green tomatillo fruits contain a small amount of α-tomatine, so ripe tomatillo fruits are not poisonous to humans and can be eaten in moderation.

The tomatillo is a unique vegetable that is commonly eaten in Mexican cuisine. Tomatillos can provide vitamins A, C, and B6 and other nutrients like iron and dietary fiber. They have a distinct, tart flavor and can be eaten raw or cooked.

Summary

Tomatillos are thermophilic vegetables belonging, like the tomato, to the nightshade family. We can eat tomatillo fruits both in raw and processed forms. The most popular dish, whose main ingredient is the tomatillo, is the traditional Latin American salsa sauce (salsa verde).