In the Northern Hemisphere, when you pull up the vines in September and October, you often find a whole batch of palm-sized squash at once. You might steam a few right away, but the rest tend to pile up in a corner of the kitchen. Slice them thin and dry them, and they'll keep well into winter. In Korea, people have long made hobak-goji, squash sliced and dried in the sun, then soaked and stir-fried it through the cold months. But the drying temperature changes how much of the flesh's orange pigment survives.
Squash Dried at Four Temperatures
The researchers worked with a small variety of moranga squash. Moranga is the Brazilian name for a round, flattened, orange pumpkin. They sliced the squash, loaded it into a tray-style hot-air dryer, and dried it with hot air at four temperatures: 50°C, 60°C, 70°C, and 80°C. Hot-air drying is a long-established, low-cost way to preserve food.
The higher the temperature, the faster moisture left the flesh. The slices dried fastest at 80°C. The researchers' calculations also showed that this kind of drying continues only as long as heat keeps coming in.
The temperature that dried the squash fastest was not the one that preserved the most pigment. The dried squash held on to the most carotenoids at 60°C. About 117 micrograms (µg) remained per gram of dried squash, and the researchers named 60°C the best drying temperature for this squash.
The nature of carotenoids suggests why 60°C came out on top. Carotenoids break down easily with heat and oxygen. At 70–80°C, more of them were likely damaged by the heat. At 50°C, the long drying time meant the slices sat exposed to air for longer. The researchers did not measure these causes directly, though.
What That Orange Flesh Does for You
The orange color of squash flesh comes from carotenoids. Some of them, such as beta-carotene, are converted into vitamin A in the body. Vitamin A helps your eyes adjust to the dark and is also needed for healthy skin and mucous membranes. That much is well established in nutrition science.
This study confirmed that dried squash still holds a generous amount of carotenoids. It did not look at what happens in the body when people eat dried squash. So it's best to think of dried squash as a food that adds some of the raw material for vitamin A to your diet in winter, when seasonal vegetables are scarce.
Carotenoids are fat-soluble. Cooking the squash in a little oil or serving it with nuts helps your body absorb more of them.
Try Drying at 60°C at Home
If you have small squash from your garden, try drying some this fall.
- Halve each squash, scrape out the seeds, and cut it into slices of even thickness. If the thickness varies, the thinner pieces tend to scorch first.
- Set your food dehydrator to 60°C (140°F). If you're using an oven, set it to its lowest temperature and keep the door slightly open so moisture can escape.
- Store the fully dried squash in an airtight container in a cool, dark place. Carotenoids slowly break down when exposed to light and air.
- To eat, soak the slices in water, then stir-fry them in perilla oil (a nutty Korean seed oil) or olive oil the way you would namul, Korean seasoned vegetable side dishes. Or add them straight to soups and porridge.
You can use the same temperature for other squash with deep orange flesh, such as kabocha or neulgeun hobak, the Korean pumpkin left on the vine until fully mature. Because this study covered only one variety, moranga, start at 60°C and check by eye whether the color stays deep after drying.
Choose one squash from today's harvest and dry it at 60°C.
Source: Journal of Food Science and Technology, a study of hot-air drying temperature and carotenoid retention in mini moranga squash, 2026
