Plukenetia volubilis Seeds | Sacha Inchi
LATIN NAME: Plukenetia volubilis
COMMON NAME: Sacha Inchi
Plant Profile
The fruit gives the plant away. Instead of a round capsule, the vine hangs a small green star of four pointed lobes, each lobe holding a single flattened seed, and the whole structure turns brown and woody as it dries. Nothing else in a warm-climate vegetable garden carries fruit of that shape, and the star is the easiest way to tell a genuine crop from a related wild vine.
The kernel carries tocopherols, with the gamma and delta forms dominating the profile, and these are what slow the breakdown of the oil in the bottle. A cold-pressed oil still needs a dark glass container and a cool shelf; heat, light and air take the freshness out of it faster than any other fault.
The vine is monoecious, and the arrangement is precise: a slender raceme carries a column of small cream male flowers, and at its base sits one female flower, usually alone or occasionally paired. Only the female flower develops into the four-lobed capsule, so seed set depends on pollen drifting down from the same inflorescence or from a neighbouring one. The stems are twining and hollow, the leaves are large, heart-shaped at the base and pointed at the tip, with a pair of small glands at the junction of blade and stalk.
The coat does not slip off easily once the seed is cool, so most small producers toast a batch and rub it between coarse cloths while it is still warm. Mechanical hullers use a rubber roller and a light air stream to separate the kernels from the coats, but the gap must be set cautiously or the kernel is crushed and the oil begins to oxidise on the spot.
Science & Biotechnology
Raw kernels taste bitter and grassy, and the bitterness sits in the hull and the thin seed coat. The seed is toasted lightly before eating or pressing, which develops the nutty note and loosens the coat so that it can be rubbed off. Cold pressing yields a pale golden oil with a soft flavour; the press cake left behind is a protein-rich meal that is milled into flour for baked goods and smoothies. Roasted whole kernels are eaten as a snack, and they are best kept in the freezer because the fats go stale at room temperature.
Uses & Benefits
The kernel is roughly half oil by weight, and about half of that oil is alpha-linolenic acid, the plant omega-3. Linoleic acid supplies most of the remainder, so the seed delivers an unusual ratio for a landrace crop: a polyunsaturated oil with omega-3 in the leading position rather than as a trace. That is the whole commercial story of the plant, and it is also its weakness, because a fat with so many double bonds oxidises quickly once the seed is crushed.
Because the oil is so unsaturated, it should never be used for deep frying. It belongs in dressings, in a bowl of cooked rice, or stirred into a cold dish at the end, and the nutty flavour survives only if the pan stays cool.
The crop has been grown in small plots along Amazonian rivers for a very long time, and the name itself comes from the local Quechua-derived word for a forest peanut. Commercial planting expanded sharply in Peru from the last decades of the twentieth century, particularly in the San Martin region, where smallholders train the vines on living posts and sell seed to pressing plants. Thailand, Vietnam and southern China have since begun their own plantations, and the oil now appears in European and North American health-food catalogues as a plant omega-3.
Growing from Seed
Wild plants scramble over riverbank trees in light shade, and the crop does best with some protection from the harshest midday sun when it is young, then full light once it is climbing well. The vine is not frost-hardy at all, and it needs a long warm season with reliable moisture; it root-rots in standing water and sulks in dry, cracked ground.
Give the vine a support of at least two metres and keep it there, because the stems twine anticlockwise and will not cling to a flat wall on their own. In a tropical plot, sturdy living fence posts serve as well as a wire trellis, and training the main stem early to a single leader produces a better-shaped plant than letting it sprawl. Sowing is done in a nursery bag and the young plant is set out when the stem has begun to search for something to climb. Prune back the tangled growth after each picking flush to keep the canopy open, feed with compost and wood ash rather than heavy nitrogen, and pick the stars as soon as they turn brown, before they split and drop seed on the ground.
Our Take
This is a warm-season vine for a gardener who will use the seed, not just grow it; a single well-tended plant can keep a household in snack kernels through the year. For other useful tropical climbers, see our pages on passion fruit, which fruits on the same kind of trellis, and mucuna, a vigorous legume cover that fixes nitrogen while it climbs. If you want a temperate nut for the same kitchen use, hazel is the reliable choice.
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