History and Origin
Quinoa, an ancient crop in the American continent, (1) has been cultivated for thousands of years in the Andean region of Bolivia and Peru. (2) According to some historical archeological documentation, the use of quinoa dates back to before 3000 BC.
Quinoa has many different native names. The Incas, American Indian people, called it “the mother grain” and used it to treat many health problems. (1)
Quinoa Plant Structure
Quinoa belongs to the family Amaranthaceae (3) or Chenopodiaceae. It is an annual broad-leaved plant, 1–2 m tall with deep penetrating roots and can be cultivated from sea level up to an altitude of 3800 m. It is not a true-grain and is considered as a fruit because it is a dicotyledon which is pseudo-grain. (1)
Quinoa is distributed worldwide and includes 250 varieties. Its classification is based on the color of the plant and fruits, or on plant morphology. (2) It has an erect stem, and bears alternate leaves that are variously colored due to the presence of betacyanins. Quinoa is a gynomonoecious species, containing both hermaphrodite and female flowers on the same plant. (5) The seeds are round and flat, about 1.5-4 mm in diameter and their color varies from white to grey and black, with tones of yellow, rose, red, purple, and violet. (2) The plant shows tolerance to frost, salinity, and drought, and has the ability to grow on marginal soils. Quinoa can grow easily in acid or alkaline conditions. (1)
The plant exhibits an enormous adaptability to different environments. Therefore, the production has spread through many different countries, including Japan, Australia, Spain, Germany, England, Sweden, Denmark, the Netherlands, Italy, France, Finland, Kenya, Ethiopia, India, the USA, Canada, etc. (6)
Fig. 1 The photo of quinoa plant Fig. 2 The photo of quinoa seeds
Quinoa Health Benefits
1. Regulating Blood Glucose Levels
Since quinoa has hypoglycemic effects and can reduce free fatty acid and triglyceride levels, its carbohydrates can be used as nutraceuticals. (7) (A nutraceutical is any food-derived substance or food with medical or health benefits, including the prevention and treatment of diseases.) (8)
According to some studies on individuals with celiac disease, the GI of quinoa was relatively lower than the common gluten-free pasta and bread. (7)
The glycemic index (GI) is a 0-100 ranking of carbohydrates based on how they impact blood glucose levels within two hours after consumption. Low GI diets (<55) have been shown to reduce insulin resistance, the risk of cardiovascular diseases, diabetes, some cancers, and also ameliorate glucose and lipid levels. Moreover, since they help control appetite, they improve weight control. Fasting insulin is reported to be lower in individuals with higher dietary fiber intakes.
A study was conducted to test a low GI diet (quinoa included). The researchers divided 210 patients with type 2 diabetes, who were treated with antihyperglycemic medications (9), into two groups: (1) high cereal fiber, and (2) low GI diet. They examined the subjects for 6 months and observed the second group experienced a greater decrease of Hemoglobin A1c (HbA1c) and an increase in HDL. (2)
(Hemoglobin A1C, also called A1C or glycated hemoglobin, is hemoglobin with glucose attached. The A1C test assesses the average amount of glucose in the blood over the last 2 to 3 months by measuring the glycated hemoglobin percentage in the blood.) (10)
2. Improving Digestive System Function
Celiac disease is an enteropathy triggered by dietary gluten, a protein found in wheat, rye, and barley. (11) A strict gluten-free diet (GFD) is a must for people with celiac disease.
Although quinoa is a highly nutritive plant and is recommended as part of a GFD, in-vitro reports indicated that quinoa prolamins could stimulate innate and adaptive immune responses in celiac patients.
Accordingly, a study was aimed to assess the in-vivo effects of quinoa in adult celiac patients.
Nineteen treated celiac patients were asked to use 50 gr of quinoa every day as part of their usual GFD. After 6 weeks, their diet, serology, and gastrointestinal parameters were evaluated. (12)
(Serologic tests are blood tests looking for antibodies in your blood. They all focus on proteins made by your immune system (13) and are very useful for screening patients with suspected CD.) (11)
The researchers also did morphometric measurements of 10 patients before and after eating quinoa. Morphometric measurements were performed on duodenal biopsies and included: villus height to crypt depth ratio (VH: CD), surface-enterocyte cell height (SECH), and the number of intraepithelial lymphocytes (IEL) per 100 enterocytes.
The normal range for these parameters are:
VH: CD between 3:1 and 5:1,
SECH between 29 and 34 μm,
IEL < 20 /100 surface cell enterocytes.
Celiac disease (CD) is normally diagnosed when the VH: CD is < 3:1, SECH is < 29 μm, and IEL > 20 / 100 enterocytes. Negative alterations of a combination of these parameters can indicate that the condition is becoming worse.
The findings showed that gastrointestinal parameters were normal, also:
- Villus height to crypt depth ratio improved from slightly below normal values (2.8:1) to normal levels (3:1). (12) Intestinal villus to crypt ratios (VCR) is commonly utilized to determine the effects of various diet regimens on gut microanatomy. (14) When villus height or villus height to crypt depth ratio increases or when the crypt depth decreases, digestion and absorption of nutrients will improve. (15)
- Surface-enterocyte cell height ameliorated from 28.76 to 29.77 μm.
- IEL decreased from 30.3 /100 enterocytes to 29.7.
- Although total cholesterol, low-density lipoprotein, high-density lipoprotein, and triglycerides decreased, median values for all blood tests remained within normal ranges.
Adding quinoa to the GFD of celiac patients did not worsen the condition and was well tolerated. This is the first clinical data which indicates using quinoa for 6 weeks (50 gr/ a day) can be safely tolerated by those with celiac disease. However, we need more studies to find out the long-term effects of quinoa consumption. (12)
One critical factor for inflammatory bowel disease (IBD) is the dysbiosis of gut microbiota, as confirmed by lots of evidence. Both in vivo and in vitro studies have shown that quinoa has potential prebiotic effects. (16) (Prebiotics are non-digestible compounds in food that selectively stimulate the growth or activity of some bacteria in the colon and improve your health.) (17)
A study was conducted to examine quinoa’s potential to improve the dysbiosis and colitis induced by dextran sodium sulfate (DSS). The researchers assigned 40 mice to two groups of AIN-93M diet and quinoa-based one. After one week of experimental diets, colitis was induced for half of the mice in each group by 5-day exposure to DSS in their drinking water (2.5%). From day 6 to 10 of the study, they were exposed to standard tap water. The other mice received standard tap water through the whole course of the study.
In summary, quinoa consumption suppressed the dysbiosis of gut microbiota and reduced clinical symptoms induced by DSS. The results revealed quinoa’s potential to improve intestinal health. (16)
3. Promoting Weight Loss
Ecdysteroids are steroid hormones with potential pharmacologic and metabolic properties in mammals. Quinoa possesses 20-hydroxyecdysone (20E), the most common ecdysteroid.
A study was aimed to investigate the ability of quinoa extract (Q) enriched in 20E supplementation to prevent the onset of diet-induced obesity and to regulate the expression of adipocyte-specific genes in mice.
The mice were randomly divided into 4 groups of 12 and were fed with a low-fat (LF) or a high-fat (HF) diet for 3 weeks (Ad libitum feeding).
The HF group was also divided into 3 subgroups: 1. High-fat diet only (HF), 2. Supplemented with Q (HFQ), and 3. Supplemented with pure 20E (HF20E).
Supplementation with Q reduced adipose tissue development in the HF group without modification of their body weight gain. This particular effect on adipose tissue was mainly associated with a reduction in adipocyte size and a decrease in the expression of several genes involved in lipid storage, including lipoprotein lipase and phosphoenolpyruvate carboxykinase.
According to the findings, Q has an antiobesity activity in vivo. Therefore, it can be used as a nutritional supplement for the prevention and treatment of obesity and obesity-associated disorders. (18)
4. Regulating Blood Cholesterol Levels
In a study, for 30 days, 22 students aged 18-45 years were treated daily with quinoa in the form of a cereal bar. They consumed two bars every day, equaling 19.5 g of quinoa. In order to determine their glycemic and biochemical profile, blood samples were collected before and after the 30-day treatment.
- The results revealed that quinoa had some beneficial effects on some subjects because total cholesterol, triglycerides, and LDL-c levels showed reductions.
- When glycemic index, weight, and blood pressure were evaluated in terms of percentage, no remarkable differences were reported. However, blood glucose levels, body weight, and blood pressure of some subjects showed reductions.
We may conclude that quinoa consumption can be effective in the prevention and treatment of risk factors related to cardiovascular diseases. However, we need more studies to prove the benefits observed. (19)
A prospective and double-blind study was conducted on 35 women with weight excess. They consumed 25 g of quinoa flakes (QF) or corn flakes (CF) daily during a period of four consecutive weeks. The subjects' blood samples were collected at the beginning and at the end of the intervention to determine their levels of glucose, total cholesterol, fractions (HDL-c, LDL-c, triglycerides), vitamin E, enterolignans, and oxidative stress markers (including thiobarbituric acid reactive substances (TBARSs), reduced glutathione (GSH)).
The researchers observed a remarkable reduction in serum triglyceride, TBARS, vitamin E concentrations, and an increase in urinary excretion of enterolignans in both groups. (20)
Urinary enterolignan concentrations are positively associated with serum HDL cholesterol and negatively associated with serum triglycerides. In other words, whenever excretion of enterolignan increases, levels of serum TG decrease, and levels of serum HDL cholesterol increase. (21)
Only the QF group observed a reduction of total cholesterol and LDL-cholesterol, and an increase in GSH, indicating a possible beneficial effect of QF intake. (20)
Ecdysteroids have hypocholesterolemic effects, best explained by increased conversion of cholesterol into bile acids. Quinoa contains significant levels of Ecdysteroids, especially in the seeds and younger leaves. (22)
Also, quinoa contains high amounts of vitamin E, iron, zinc, and magnesium, saponins, and phytosteroids, which all have shown hypocholesterolemic effects. Researchers found antioxidant compounds (such as polyphenols, phytosterols, flavonoids) and dietary fiber in quinoa seeds may be related with reducing plasma lipids. (23)
5. Increasing Antioxidant Activity
Quinoa seeds contain significant amounts of antioxidant phytochemicals which can change antioxidant status in the organism, including flavonoids, phenolic acids, fat-soluble vitamins, fatty acids, trace elements, squalene, and other compounds. These non-enzymatic antioxidants, compounds of quinoa seeds, prevent oxidative stress. (Oxidative stress acts as a mediator of damage produced by fructose metabolism.)
A study was conducted to explore the effects of a diet enriched with quinoa seeds on oxidative stress in plasma, heart, kidney, liver, spleen, lung, testis, and pancreas of the fructose-administered rats.
Fructose administration (310 g/kg fodder for 5 weeks) caused oxidative stress. Oxidative stress was indicated by the increase in plasma malondialdehyde (MDA) and by the nonsignificant changes in the enzymatic antioxidant potential in plasma and most tissues.
Co-administration of quinoa seeds (310 g/kg fodder) maintained normal activities of some enzymes. Furthermore, MDA reduction and the decrease of the activities of antioxidant enzymes (erythrocyte superoxide dismutase (eSOD), catalase (CAT), and plasma glutathione peroxidase (pGPX)) showed that it also influenced oxidative stress.
The findings revealed that quinoa seeds could act as a moderate protective agent against fructose-induced changes in rats by increasing the antioxidant capacity of blood (plasma) and heart, lung, kidney, testis, and pancreas and by reducing lipid peroxidation. (24)
6. Improving Liver Function
A study was done to assess the effect of quinoa seed on carbon tetrachloride (CCl4)-induced liver toxicity in Swiss albino male mice.
The mice were divided into three groups of 20:
Group 1: Normal control (the mice who consumed olive oil (vehicle) for 12 weeks.)
Group 2: hepatotoxic group (CCl4-treated group for 12 weeks)
Group 3: quinoa seed powder (20 mg/kg) + CCl4-treated group for 12 weeks.
The effects on liver tissue were studied after three different periods of 4, 8, and 12 weeks. The researchers measured liver marker enzyme level of serum glutamic-oxaloacetic transaminase or (AST), serum glutamic-pyruvic transaminase or (ALT), serum alkaline phosphatase, and liver antioxidant enzyme level of lipid peroxidation, superoxide dismutase, and reduced glutathione. They also conducted the histopathological analysis of the liver.
The results exhibited that the treatment with quinoa seed powder significantly reduced CCl4-induced, elevated serum level of hepatic enzymes and also restored the level of liver antioxidant enzymes toward the normal levels; the histopathological analysis confirmed the same too.
The researchers concluded that quinoa seed has some hepatoprotective effects against CCl4-induced liver damage in Swiss albino male mice. (25)
7. Relieving Menopause Symptoms
Dietary lignans are metabolized to two major enterolignans by gut bacteria: enterodiol (END) and enterolactone (ENL).
END and ENL may show some weak estrogenic effects through binding to the estrogen receptor. Moreover, there is evidence of anti-inflammatory and antitumorigenic activities, as well as reduced oxidative stress with increased consumption of lignans. (26)
Estrogen deficiency in postmenopausal women may lead to chronic diseases. Inflammation is highly prevalent during the postmenopausal phase, and some cereals show anti-inflammatory effects. Therefore, a prospective and double-blind study was designed to investigate the effect of quinoa and corn flakes intake on blood inflammatory markers and urinary enterolignans of a group of sedentary overweight postmenopausal women. The researchers assigned 34 women into two groups of 17. The participants consumed 25 grams of quinoa or corn flakes daily for 4 weeks. They could add quinoa or corn flakes to fruits, juice, fruit milkshakes, and/or during their lunch or dinner. They were requested not to consume other food sources of lignans, such as flaxseed and soy.
At the beginning (T1) and at the end (T2) of the intervention, the researchers measured serum inflammatory markers (including interleukin-6 (IL-6), tumor necrosis factor α (TNF-α)), and urine enterolignans (including urinary enterolactone (ENL)).
At T1, interleukin-6 (IL-6) was higher in the quinoa group compared to the corn flakes group. However, at T2, they presented similar levels. It showed that supplementation with quinoa could decrease IL-6, a marker of inflammation.
The results suggested that an acute quinoa flakes intake during 4 weeks reversed IL-6 serum levels in a group of overweight postmenopausal women, demonstrating that we can consider quinoa for the treatment of inflammation in postmenopausal women. (27)
8. Regulating Blood Pressure
It is well-documented that the quality of quinoa protein matches that of milk casein, and quinoa contains large amounts of several micronutrients such as potassium, iron, calcium, and riboflavin (vitamin B₂). (28) Potassium, an important component of cell and body fluids, helps controlling heart rate and blood pressure. (29)
A study was conducted to investigate the functional properties of quinoa (dehulled quinoa flour) on spontaneously hypertensive rats (SHR) with hyperlipidemia induced by a high-lipid diet.
12 male rats were assigned into two groups: experimental and control. The first group was fed with a quinoa diet and the second with a high-lipid casein diet for 6 weeks. The diets' components were adjusted.
During the first two weeks, the food intake and growth rate were significantly decreased in the experimental group. However, such differences were not observed after two weeks. The increase in systolic blood pressure in the experimental group was significantly suppressed at 5 weeks of feeding, suggesting that quinoa had a hypotensive effect. (28)
What Are Quinoa Side Effects?
1. When Taken by Mouth
Quinoa is LIKELY SAFE when taken as food. There isn't enough reliable information about the safety of large amounts of quinoa as a medicine or the potential side effects. Some people are allergic to quinoa.
2. Pregnancy and Breast-Feeding
There isn't enough reliable information about the safety of quinoa during pregnancy or while breast-feeding. So, stay on the safe side and avoid consuming amounts higher than those found in food.
3. Allergy to Other Foods Used as Grains
Individuals who are sensitive to foods used as grains such as buckwheat, wheat, and rice may be allergic to quinoa too. So, if you have allergies to grains, consult with your healthcare provider before using quinoa. (30)
4. Cross-Reactive Foods
Quinoa, spinach, beets, and Swiss chard belong to the same family. Therefore, since they’re related, you may experience similar allergic reactions to quinoa as you would with a chard allergy.
5. Saponin Allergy
Saponin, a bitter and soapy substance, protects the quinoa plant from fungal and insect attacks. It also contains some toxins which can cause irritation, etc. in some people. Although the level of toxicity is low, you may be sensitive to this compound.
Some people have reported that after eating quinoa for a while, they have experienced intolerance or allergy to it. This is often caused by saponin. (31)
Saponin is removed by soaking or roasting quinoa seeds before cooking. If not removed, it can cause an upset stomach and can even hurt the function of the small intestine. (32)
If you have intolerance or allergy to saponin only, you can still include quinoa in your diet on the condition that you wash the seeds well. This will help remove the natural coating which contains saponin. (31)
6. Prolamins (Gluten-Free but Beware)
Quinoa is gluten-free. Therefore, it is a good option for those suffering from celiac disease, wheat allergy, or gluten sensitivity. Some types of quinoa contain prolamins, a substance that can provoke an immune response in people with celiac disease. However, most types of quinoa do not contain prolamins, and we need more studies to verify the effect of this substance.
Moreover, a study showed that quinoa was well-tolerated by celiac patients as a part of their gluten-free diet.
7. Oxalate Warning
Many plant-based foods, including quinoa, naturally contain different amounts of a substance called oxalate or oxalic acid. Although nearly all of the oxalic acid you consume is excreted in the urine, it can bind with calcium and may form kidney stones in people who are susceptible to calcium oxalate stones.
If you have ever suffered from kidney stones, consuming foods high in oxalic acid like quinoa may enhance the risk of developing more stones in the future. So, if you follow a low-oxalate diet, talk with your healthcare provider before eating quinoa.
8. High-Fiber Side Effects
One cup of cooked quinoa contains 5 grams of fiber. This amount is high enough to cause side effects if you're not used to eating a lot of fiber. If you experience gas, diarrhea, or bloating after eating quinoa, it may be caused by fiber. You are recommended to start with smaller portions and add fiber to your diet gradually. As you increase your fiber intake, make sure to drink enough water or non-caffeinated beverages. (33)
Generally, every person can have an allergy to certain herbs and spices. This sensitivity must be first diagnosed by the person and secondarily by the physician. However, these allergic reactions do not cause chronic or acute side effects; after identifying the allergenic plant and eliminating it from their diet, allergy-related complications will be gone away.
No company or product can be aware of the allergic reactions of different bodies in advance. The body's incompatibility with one or more specific herbs rarely occurs, but some consumers may encounter it anyway.
Nutritional Information
Quinoa grain is highly nutritious because of its outstanding protein quality and wide range of minerals and vitamins. Two factors may affect its yield and nutritional quality: Genetic and environmental conditions.
Protein and Amino Acid Content: The protein content of quinoa seeds varies between 11% and 19%. The seeds also contain all nine essential amino acids (i.e. Isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine, and Histidine). (34) The grain protein is rich in amino acids like lysine and methionine that are deficient in cereals.
Carbohydrates: The carbohydrate content of quinoa seeds varies between 49% and 68% (dry matter weight). Starch is the main and the most abundant carbohydrate present in quinoa seeds. Another carbohydrate is dietary fiber (34) (soluble and insoluble fiber). (35)
Fat: The fat content of quinoa seeds ranges between 2% and 9.5%. Quinoa oil is rich in essential fatty acids such as linoleic (49.0%–56.4%), oleic (19.7%–29.5%), and linolenic (8.7%–11.7%). 87%-88% of total fatty acids of the seeds are (poly-) unsaturated fatty acid. (34)
Moreover, oil content in quinoa contains high concentrations of natural antioxidants such as α- and γ-tocopherol. (3)
Minerals: Quinoa has higher total mineral (ash) content than durum wheat, white rice, yellow corn grain, and other cereals. (36) The ash content of quinoa seeds varies between 2.4% and 4.8% and is a good source of minerals, including a high content of calcium, magnesium, iron, copper, and zinc. (34)
Phytosterols: The total phytosterols content reported in quinoa varies from 38.8 to 82.5 mg/100 g. The main components include β-sitosterol, campesterol, brassicasterol, and stigmasterol. (36)
Phenolic compounds: The total polyphenol content determined in quinoa seeds is between 0.46 and 1.84 mg/g dry weight. Flavonol glycosides represent the most abundant phenolics in this plant. Quinoa seeds contain flavonoids (mainly orientin, vitexin, and rutin, morin, hesperidin, and neohesperidin) and phenolic acids (such as ferulic, caffeic, and p-coumaric acids). (36)
Vitamins: Quinoa is packed with vitamins, namely Cobalamin (B12) (36), riboflavin (B2), folic acid (B9), and thiamine (B1), but is a lesser source of niacin (B3). (34) It also contains vitamins E, C (3), and D3. (36)
Bioactive Compounds
Bioactive compounds in quinoa include saponins, phytosterols, phytoecdysteroids, phenolic compounds, polysaccharides, betalains, bioactive proteins, and peptides. (36)
Possible Drug Interactions
We currently have no information for quinoa interactions. (30)
Traditional Use
Some indigenous peoples of South America have been traditionally using quinoa. They consume the seeds like rice, prepare them in soup, puff them to make breakfast cereal, or grind them into flour to produce toasted and baked goods (cookies, bread, biscuits, noodles, flakes, tortillas, and pancakes) (37)
Some Questions about Quinoa
Can I eat too much quinoa?
Like every other type of food, consuming too much quinoa may cause some not-so-good side effects. Quinoa contains a high amount of fiber compared with other grains (nearly two times more). Fiber is a key nutrient in every diet because it causes a feeling of fullness and is good for the digestive system. (38) Consuming too much quinoa will lead to too much fiber intake. Subsequently, too much fiber may lead to nutrient deficiencies because it can reduce the body's ability to absorb essential nutrients. (39)
You are recommended to pay the most attention to the portion size because quinoa seeds contain a considerable amount of calories. (38) Preserve a single serving (1/4 cup of uncooked quinoa) which has about 170 calories. It is easy to overeat, and the calories do add up fairly quickly. (41)
Can I eat quinoa on a low-carb diet?
Although quinoa is a highly nutritious food and has less starch than other cereals, it contains pretty high amounts of carbs. There are approximately 40 grams of carbohydrates in a one-cup serving, which may be too much for individuals following a ketogenic diet. (42)
Generally, 1/3 cup of cooked quinoa is considered as one carbohydrate serving (about 15 grams of carbohydrate). Consult a dietitian to make sure how quinoa will fit into your meal plan. (40)
Is quinoa better than rice for diabetics?
People with diabetes need to choose foods in the medium or low GI category. A glycemic index (GI) of 55 or below is considered low. (44) Low GI diets help control appetite. So, they can improve weight control, glucose and lipid levels. They also reduce insulin resistance and the risk of cardiovascular diseases, diabetes, and some cancers. The GI of quinoa depends on the cooking time and ranges between 35 and 53. The GI of medium grain white rice varies between 75 and 89.
Moreover, fasting insulin seems to be lower in individuals with higher dietary fiber intakes. (2)
Quinoa contains high amounts of dietary fiber compared with many other grains, which means it can be beneficial for people with diabetes.
Note: Controlling total carbohydrate intake per meal is crucial for blood sugar regulation. One cup of cooked quinoa (189 grams) contains about 40 grams of carbohydrates. (44)
Rice or quinoa? Which one is better for weight loss?
It depends on your needs and requirements.
- Quinoa contains more amino acids and protein compared with white and brown rice. Therefore, it is a better option for people trying to lose weight. (43)
- Quinoa contains more fiber than white or brown rice (5 grams of dietary fiber per cup). Fiber helps prevent constipation, control blood sugar levels, lower cholesterol, and maintain a healthy weight by causing a feeling of fullness. (45)
- Although quinoa contains more calories than white and brown rice, these calories are worth the nutrition it provides.
Why is it important to rinse quinoa before cooking?
Quinoa has a natural bitter coating that should be rinsed off before cooking. We recommend you to presoak quinoa in 3-4 times the amount of water overnight, or at least for 6 hours. Then, just drain it, rinse, and cook.
When you presoak quinoa, it cooks much more quickly than unsoaked. (46)
How do you cook quinoa?
1. Pour soaked quinoa seeds into a fine mesh colander and rinse under running water for at least 30 seconds. Drain well.
2. Add rinsed quinoa seeds, water, or broth to a saucepan and stir.
The ratio of water to quinoa:
- 1 part uncooked and rinsed quinoa (e.g. 1 cup quinoa)
- 2 parts water or vegetable/chicken broth (e.g. 2 cups water)
3. Bring the mixture to a boil. Then, turn the heat down to maintain a gentle simmer. Cook them until the seeds have absorbed all of the water.
4. Remove the saucepan from heat, put the lid on it, and let the seeds steam for 5-10 minutes.
This step gives the seeds time to pop open into little curlicues.
5. Remove the lid and fluff quinoa seeds with a fork (4)
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