Perilla Seed

Perilla frutescens is an annual aromatic herb with broad, toothed, green or purple leaves and spikes of small flowers. The seeds, which develop in small calyx clusters, are about 1.5 millimetres across, round and rough-coated, ranging in colour from grey to brown. They have a nutty, earthy and somewhat herbal flavour that becomes richer when roasted. Perilla seed is high in oil, a large share of which is alpha-linolenic acid, an omega-3 fatty acid. The leaves of the same plant are eaten in Japan as shiso and in Korea as kkaennip.

Perilla is native to East Asia and the Himalayan foothills and has been cultivated for centuries in China, Korea, Japan, Vietnam, India and Nepal. It grows easily in a range of soils and climates and is often grown as a field crop or kitchen garden herb. Seed crops are harvested when the plants dry, then threshed. In Korea the seed is called deulkkae, and it is a distinct crop from the leaf-type perilla, though both are the same species.

Perilla seed is known from archaeological sites in East Asia, suggesting very early use, and the oil was important in Japan and Korea as a cooking, lamp and varnish oil. In Chinese traditional medicine the seed and leaf have long been used for different purposes. In Japan the oil, called egoma oil, was used in Buddhist temple cooking and for waterproofing paper umbrellas.

In Korea, perilla seed oil, known as deulgireum, is used for seasoning and dressings, and ground perilla seed is added to soups and stews, such as deulkkae soup, for thickness and flavour. Interest in omega-3-rich oils in recent decades has led to increased research and marketing of perilla oil as a plant alternative to fish oil. Egoma is also grown in Japan's mountain regions for local products.

Perilla seeds are toasted and ground to season soups, stews, vegetables and rice dishes in Korea, and mixed into dipping sauces. In Japan, the seed is added to rice balls and sweets. Perilla oil is typically used as a flavouring or finishing oil in small amounts, since it is highly sensitive to heat and spoils quickly. Ground seed adds richness and body to sauces. Store the oil refrigerated in a dark bottle and use it soon after opening.

Perilla seeds are rich in alpha-linolenic acid, a plant omega-3 fatty acid, and also contain protein, fibre and polyphenols such as rosmarinic acid and luteolin. The body converts only a small share of plant omega-3 to the longer-chain forms found in fish oil. Composition varies with variety, and the figures shown are approximate. Evidence on health effects comes largely from laboratory and small studies, so the seed is best considered a nutritious flavouring.