Have you ever made lomilomi salmon with bits of salted salmon, diced tomatoes, chopped green onion
and chopped regular, run-of-the-mill, yellow onion? I have. I ended up with lomilomi salmon that bit back, thanks to the harshness of the belligerent onion. Lesson learned. Now, I always use friendly, sweet Maui onions in lomilomi salmon, and in other dishes that call for raw onion.
What Makes Maui Onions Sweet?
To understand why Maui onions are sweet, it's helpful to know what makes other onions not so sweet. Regular onions have high levels of sulfur compounds, which contain pyruvic acid. It's this acid that makes onions "hot," harsh, pungent, and causes your eyes to tear when slicing or dicing them.
We can trace the origin of Maui onions to Texas, where sweet onions were developed from Bermuda onions. Maui onions (and Georgia's sweet onion, the Vidalia) are hybrids of the early Texas onions.
Maui onions are grown in Kula on the slopes of Haleakala, where the altitude is high (about 3,500 feet above sea level), temperatures are cool, and the soil is rich and low in sulfur. This combination produces onions with less sulphur and more water than regular onions. "Maui" and "Kula" onions are trademarks owned by the Maui Onion Growers Association.
Yet higher sugar content does not necessarily make an onion sweet. Some regular onions actually contain more sugar than sweet onions, but the sulphur masks their sweetness. The Maui onions' low sulphur content allows the sweetness to come through.
Because of their mildness, perhaps we can forgive Maui onions for their shortcomings as a nutritional powerhouse. Other than its most significant nutrient (potassium, about 126 mg. in a half cup chopped onion), onion nutrition is sadly lacking: 7 g. carbohydrate, 1 g. protein, 1 g. fiber, 5 mcg. vitamin C. We can rejoice, however, in its low-calorie (30 calories), no-fat, no-sodium profile, and its ample supply of quercetin, a flavonoid (a chemical found in plants) that is believed to help prevent atherosclerosis.
Use Your Onion Wisely
Frankly, Maui onions aren't cheap. They may cost three to four times more than regular onions. If sweet onions go on sale, however, don't stock up on them. Their high water content causes them to spoil faster than regular onions.
So when I get my hands on Maui onions, I like to use them wisely. Or shall I say, "correctly." And that means raw or nearly so, chopped and mixed into a tuna sandwich, or sliced to top a veggie burger or any other sandwich with tomato and green leaf lettuce. The Maui onions are also good in stir-fries, as long as you're careful to cook them ever-so-briefly. While onion measurements specified in recipes need not be precise, as far as I'm concerned, it may be helpful to note that one pound of onion will give you 2 cups chopped or about 3 cups sliced.