Pumpkin Seeds

Pumpkin seeds are among the more zinc-dense foods available without supplementing, and zinc's role in immune function and in male reproductive physiology is the reason the seed appears so often in that literature. Research on pumpkin seed oil in benign prostatic hyperplasia exists and has produced some positive results on symptom scores, though trials have generally been small and several were industry funded, so the finding should be read as promising rather than established.

They are also a good source of magnesium, iron and plant protein, and they contain phytosterols, which is the proposed mechanism behind the prostate work.

The sleep association comes from tryptophan, the amino acid precursor to serotonin and melatonin, which pumpkin seeds carry in useful amounts alongside magnesium. The leap from that to a reliable sleep effect from eating a handful at night is larger than most articles admit, since tryptophan competes with other amino acids for transport and dose matters.

Like all seeds they are calorie dense. Roughly 560 calories per 100g hulled.

Squash was one of the three sister crops of Mesoamerica, grown alongside maize and beans, and the seed was never a byproduct there. Ground pepitas are the base of pipián verde, a sauce that predates the arrival of Europeans and is still made the same way, and toasted salted pepitas remain an everyday street snack across Mexico.

The seed travelled with the squash after the sixteenth century. In China it became guazi, part of the enormous category of seeds cracked between the teeth during conversation, alongside sunflower and melon seeds, and it is a fixture of new year snack trays. In Korea the seeds return to the squash they came from, scattered over hobakjuk as garnish. In India, ground melon and squash seeds, sold together as magaz, thicken Mughal-style kormas and sweets.

What is striking is that Mexico and India arrived independently at the same technique: toast the seed, grind it, and use it to give a sauce body without flour or dairy.

The defining technique is grinding. Toasted and ground with chilli, tomatillo and herbs, pepitas become pipián verde, and the same move thickens a Mughal korma when the seeds are sold as magaz. In both cases the seed replaces dairy or flour as the body of the sauce.

Whole and toasted they are a garnish and a snack. Korean hobakjuk gets a scatter of them, partly for the echo of the squash in the bowl. Chinese snack trays use the unhulled seed, cracked between the teeth.

They also work where you would use a pine nut and do not want to pay for one, since the flavour is greener and less resinous but sits in the same register. Blitzed into a paste with oil and garlic they make a workable pesto.

Do not add them late to a wet dish expecting crunch. They soften quickly.

Toast them in a dry pan over medium heat and listen rather than watch. They pop audibly and puff slightly, which takes two to three minutes, and that is the signal. Past that they go bitter.

For pipián and for magaz-style gravies, toast first and grind while still warm, which releases the oil and gives a smoother paste. A blender needs liquid; a spice grinder does not.

Salt them after toasting, not before, or the salt draws moisture and they steam instead of crisping.

Store them cold. Hulled green pepitas have no shell to protect them and go rancid within a few months at room temperature. Buy them somewhere with turnover, and keep the bag in the fridge or freezer. A dull, flat, slightly fishy smell means they have turned.