Nuts are extremely healthy, and they can be a great quick snack. They are rich in healthy fats, fiber and protein, and overall are an excellent source of many important nutrients and antioxidants. However, some people wonder if their roasting has beneficial effects. Which nuts are healthier - roasted or raw? Studies have shown that eating nuts has several health benefits, including lowering cholesterol, blood pressure, and blood sugar.
Why are nuts roasted?
To understand what is more beneficial - roasted nuts or raw, you should understand why their processing is necessary. Nuts are usually fried to improve their taste, aroma and get a crispy texture. Roasting is defined as cooking using dry heat, which evenly cooks the product from all sides. Most nuts are roasted without a shell, with the exception of pistachios.
Meanwhile, raw nuts are not subjected to any processing. Sometimes roasting methods are used to separate the shells of nuts from their kernels. This is a common way of processing cashews and at the same time the reason they are almost never sold raw.
There are two main types of frying:
- Dry, no oil added. Nuts can be dried in this way in the oven or in a pan.
- Using oil. The product is also cooked in the oven or in a pan.
In addition to these two methods, nuts can be roasted in a microwave.
You can buy the product already cooked or make it yourself.
How does frying affect the product?
Are Roasted Nuts Useful? The prepared product changes the structure and chemical composition. In particular, nuts change their color, and the moisture content in them decreases, which leads to the appearance of a crispy texture.
Raw and roasted nuts have approximately the same amount of fat, carbohydrates and protein. Although the latter sometimes contain a little more fat and calories per gram, the difference is minimal.
So, 28 grams of raw almonds contains 161 calories and 14 grams of fat, while the same amount of fried almonds contains 167 calories and 15 g of fat.
Similarly, 28 grams of raw pecan contains 193 kcal and 20 g of fat, the same number of nuts after dry frying has indicators of 199 kcal and 21 g, respectively.
During heat treatment, the product loses moisture. Therefore, it weighs less than raw. This explains why the fat content is slightly higher.
Some studies have shown that roasting nuts does not alter the overall fat content. However, polyunsaturated fats in them become more susceptible to oxidation, as the structure of the product changes.
Then which nuts are healthier - roasted or raw? Meanwhile, the protein and carbohydrate content in raw and fried kernels is very similar. However, in fried foods there may be slightly more or fewer macronutrients, depending on their type.
Oddly enough, cooking with oil only increases fat and calories compared to dry processing. This is because the product absorbs additional oil.
Roasting can damage healthy fats.
Nuts are high in monounsaturated and polyunsaturated fats. They have the ability to lower blood cholesterol and can protect against heart disease. Are Roasted Nuts Useful?
High temperatures and long cooking times have the greatest effect on the composition of the product. When polyunsaturated fats are exposed to heat, they are likely to be damaged or oxidized. This can lead to the formation of harmful free radicals, which can damage the body's cells.
Oxidized or rancid fat is responsible for the specific taste and smell in some nuts. Fortunately, you can reduce the formation of these free radicals by controlling the roasting process.
What is the effect of frying?
Therefore, you must adjust the temperature and cooking time. Studies have shown that when nuts are roasted at low and medium temperatures, their fats are less likely to be oxidized.
Another test showed that the higher the temperature and the longer the cooking time, the more likely the product will contain a substance that indicates oxidation. The likelihood of oxidation also depended on the type of nuts.
For example, when walnuts are fried under extreme conditions at 180 ° C for twenty minutes, oxidation increases by 17 times compared with the raw product. Moreover, this indicator increases only 1.8 times in hazelnuts and 2.5 times in pistachios.
This is due to the large amount of polyunsaturated fat in walnuts. It accounts for 72% of the total content of this nutrient. Are Roasted Walnuts Useful? The harm from oxidized fats can be palpable, so this product is best eaten raw.
Oxidation may occur during storage.
Polyunsaturated fat in nuts is also more vulnerable to oxidation during storage. This is due to the fact that the structure of the product changes when it is fried, which makes fat easier to contact with oxygen and thus oxidize.
This reduces the shelf life. Thus, fried kernels should be stored for shorter periods than raw ones.
In addition, some studies show that trans fats also form after frying. But their number is insignificant. Which nuts are healthier - roasted or dried? Since drying is the same frying, but without the use of oils, such a product is more healthy.
Some nutrients are lost during frying.
Nuts are an excellent source of nutrients, including vitamin E, magnesium and phosphorus. They are also rich in antioxidants. Some of these nutrients are heat sensitive and may be lost during the roasting process. These include antioxidants. The same characteristics apply to peanuts, which are not nuts. What are the benefits of roasted peanuts for women? They contain unsaturated fats that support the proper functioning of the heart and blood vessels. But the negative effects of frying for them are also relevant.
In one study, antioxidant levels in various nuts were constantly reduced by frying at 150 ° C for up to 30 minutes. It is also interesting that antioxidant activity increased after 60 minutes. This is due to the fact that compounds with this ability are formed during a chemical reaction that occurs during frying.
In addition, not all antioxidants are damaged when heated. The test results reported that the amount of lutein and zeaxanthin in fried pistachios and hazelnuts does not change.
Studies also show that vitamin E, thiamine, and carotenoids disappear during heating. However, the degree of their loss depends on the type of nut and the firing temperature.
In fact, one study showed that frying almonds and walnuts causes a greater loss of vitamins than the same processing of hazelnuts, while heating pistachios does not have such an effect on their composition.
The degree of loss of vitamins increases in accordance with an increase in the frying temperature. So, the level of alpha-tocopherol is also affected during heating. When processing for 25 minutes at a temperature of 140 ° C, its amount is reduced by 20% in almonds and 16% in hazelnuts, compared with the raw product.
The higher the cooking temperature, the more alpha tocopherol is lost. After 15 minutes of frying at 160-170 ° C, its levels were reduced by 54% in almonds and 20% in hazelnuts compared to raw nuts.
Thiamine levels also decreased during frying, in direct proportion to temperature. However, the amount of riboflavin was not affected.
Which nuts are healthier - roasted or not? In general, each type of product and the level of each nutrient in them react differently to frying. Although some vitamins are lost during heating, keep in mind that nuts are, in principle, not the main sources of these substances. The exception is almonds, which contain large amounts of vitamin E.
Roasted nuts may contain harmful chemicals.
Which nuts are healthier - roasted or raw? The rich aroma, color and crisp texture of roasted nuts are explained by the compounds that form during a chemical reaction called the Maillard reaction. It occurs between the amino acid asparagine and the natural sugar in the product. This happens when nuts heat up above 120 ° C and as a result they turn brown.
The Maillard reaction may also be responsible for the formation of the harmful substance acrylamide. It is known to cause cancer in animals when consumed in very high doses. It can have potentially cancer-causing effects in humans, but there is insufficient evidence for this.
How to reduce this harm?
The frying temperature has a greater effect on the formation of acrylamide than the duration. Almonds are most susceptible to the formation of this substance because it contains a large amount of the amino acid asparagine.
Acrylamide begins to form in the almonds when the nuts heat up above 130 ° C. The concentration of this substance becomes especially high at temperatures above 146 ° C.
Is roast nuts harmful? In different cores, different levels of acrylamides are observed during frying. So, the level of this compound almost doubled in pistachios, when they were fried at the same temperature as the almonds. However, no acrylamide was found in macadamia, walnuts or hazelnuts.
It is important to note that even if you are exposed to acrylamide in almonds, as well as in other products, these amounts are not considered harmful. However, if you want to minimize the effect of this substance, be sure to fry the product at a relatively low temperature (about 130 ° C).
Raw nuts may contain harmful bacteria and fungi.
Which nuts are healthier (roasted or raw), given the presence or absence of heat treatment? Potentially harmful bacteria, such as salmonella and E. coli, may be present in raw kernels. This is because nuts sometimes fall to the ground during harvesting. If the soil is contaminated with bacteria, the products easily come in contact with them.
Contaminated water may also contain harmful microorganisms and enter the nuts during or after harvest.
Is it so dangerous?
In fact, salmonella is found in raw nuts, including almonds, macadamia, walnuts, and pistachios. One study reported that almost 1% of samples from various nuclei contained this dangerous bacterium. It was not found only in pecans.
However, the number of detected Salmonella was low, so it may not cause disease in healthy people.
In addition, raw nuts may contain poisonous carcinogenic aflatoxin, which is produced by fungi that sometimes infect plant kernels and seeds. However, this substance is very persistent and can survive the frying process. The best way to avoid aflatoxin contamination is to control humidity and temperature during drying and storage, rather than roasting.
What is the best to eat?
The short answer is both types. Raw nuts are very healthy, but may contain harmful bacteria. However, even if this happens, it is unlikely to cause the disease.
The benefits and harms of roasted nuts are already known to you. They may contain less antioxidants and vitamins. Some of their healthy fats can also oxidize, and acrylamide can form, although not in harmful amounts.
As a result, the temperature and duration of the roasting can have a big impact. If you do this at a temperature of about 140 ° C for about 15 minutes, beneficial substances will not disappear, and harmful ones will not have time to form.
If you want to eat roasted nuts sold in stores, keep in mind that they are often seasoned with salt, and some are even coated with sugar. Therefore, it is better to buy them raw and fry yourself, preferably in the oven.