Onions

In the scientific community, onion goes by the name of Allium cepa. Onion is more commonly known as a culinary and therapeutic spice in the kitchen when crushed into powdered form. The powdered spice form of onion has its benefits, but it's the raw onions of whole natural foods.

Let's cover the nutritional profile, chemistry, and health benefits of one famous whole food and spice.

Nutritional Profile of Raw Onions

Onions are 89% water. The rest of the 11% content comes in the form of carbohydrates, minerals, fibers, and vitamins. ((USDA), 2020)

Carbohydrates

Carbohydrate content consists of dietary fibers and five different types of sugar, namely sucrose, glucose, fructose, lactose, maltose.

Minerals

Some of the major mineral constituents of onions include calcium, magnesium, and potassium.

Vitamins

Ascorbic acid and biotin are the two main vitamins found in onions.

Chemistry of Onions

The chemistry of onion revolves around a few critical compounds:

• Alliinase
• Thiosulfinates
• Propanethial-S-oxide

Interestingly, though, these compounds are only activated when the onion is damaged or cut. (Gareth Griffiths, 2002) Damaged onion flesh triggers the enzyme alliinase, which acts on the precursor molecules and converts them into thiosulfonates and propanethial-S-oxide.

Significance of Thiosulfinates

Thiosulfinates are responsible for flavor, odor, and the infamous crying effect of onion. And because of the way they are synthesized, thiosulfinates are a flavor controlling factor.

Health Benefits of Onions

Boosts the Immune System

The flavonoids and cysteine sulfoxides present in onions offer multiple health benefits, including anti-cancer properties, antiasthmatic properties, and antibiotic effects. (Hafiz Ansar Rasul Suleria, 2015)

Antiplatelet Activity

Platelet inhibition is good, at least to an extent.

One onion serving can drop the activity of the platelets within an hour, which reduces the risk of having a cardiac disorder or stroke. (Greger, 2016)

Grow Hydroponic Onions

Hydroponic cultivation of onions require the following things:

Variety of Onion

Based on the daylight requirements, onions fall into three categories:

• Short-day onions
• Intermediate onions
• Long-day onions

Considering the factors like cost-effectiveness and the size of the harvest, short-day onions are an ideal choice for hydroponics.

Hydroponic System

The choice of a hydroponic system depends on your scale of operation. The Kratky method is suitable for low-scale production. While for high-volume harvesting, it's best to opt for the nutrient film technique.

Nutrient Solution

Slightly acidic, half-strength Hoagland's solution is a proven nutrient solution for better onion growth. (Chad D. Kane, 2006)

The fertilizer level of 120:50:50 NPK maximizes the harvest and thereby increasing your ROI.

Onions are rich in flavor and nutrition, which makes them an essential item to be consumed as a part of whole foods or spices.

References

1. (USDA), U. D. (2020, April 1). FoodData Central. Retrieved from U.S. DEPARTMENT OF AGRICULTURE-Agricultural Research Service: https://fdc.nal.usda.gov/fdc-app.html#/food-details/790577/nutrients
2. Chad D. Kane, R. L. (2006). Nutrient Solution and Solution pH Influences on Onion Growth and Mineral Content. Journal of Plant Nutrition, 29(2), 375–390. https://doi.org/10.1080/01904160500477028
3. Gareth Griffiths, L. T. (2002, November). Onions—a global benefit to health. Phytotherapy Research, 16(7), 603–615. https://doi.org/10.1002/ptr.1222
4. Greger, M. (2016, March 9). Inhibiting Platelet Activation with Garlic & Onions. Retrieved from NutritionFacts.org: https://nutritionfacts.org/video/inhibiting-platelet-activation-with-garlic-and-onions/
5. Hafiz Ansar Rasul Suleria, M. S. (2015). Onion: nature protection against physiological threats. Critical Reviews in Food Science and Nutrition, 55(1), 50–66. https://doi.org/10.1080/10408398.2011.646364