This is because compounds that have antioxidant activity are formed in a chemical reaction when nuts are roasted ( 13, 22).įurthermore, not all antioxidants are damaged by roasting. Interestingly, the antioxidant activity increased after 60 minutes. In one study, the levels of antioxidants in various nuts decreased constantly from the start of roasting at 302☏ (150☌) until 30 minutes later ( 22). Nevertheless, increased temperature and roasting time have been shown to decrease antioxidant activity, but only up to a certain point.
#Roasted cashew nuts health benefits free
Antioxidants are important for your health because they help protect your cells against damage from free radicals ( 13). Some of these nutrients are sensitive to heat and might be lost during the roasting process.įor example, some types of antioxidants are degraded during roasting. Nuts are a great source of nutrients, including vitamin E, magnesium and phosphorus. Also, roasting nuts shortens their shelf life. Summary: Roasting might damage the healthy polyunsaturated fats in nuts, but you can help minimize this damage by roasting at a low temperature. Thus, roasted nuts should be stored for shorter periods than raw nuts.įurthermore, some studies indicate that trans fats are formed after roasting, but the amount is negligible ( 20, 21). This is because the structure of nuts changes when they’re roasted, allowing fat to come into contact with oxygen more easily and thus become oxidized ( 7). The polyunsaturated fat in nuts is also more vulnerable to oxidation during storage. In the same study, when walnuts were roasted at a medium temperature (248–320☏ or 120–160☌), the extent of oxidation was much lower ( 13). It accounts for 72% of their total fat content, which is the highest fat content of all nuts ( 19). This is explained by the high amount of polyunsaturated fat in walnuts. In comparison, the substance that indicated oxidation only increased by 1.8 times for hazelnuts and 2.5 times for pistachios ( 13). The likelihood of oxidation also depended on the nut type ( 13).įor example, when walnuts were roasted under extreme conditions at 356☏ (180☌) for 20 minutes, the substance that indicated oxidation increased by 17 times, compared to raw walnuts ( 13). One study showed that the higher the roasting temperature and the longer the roasting time, the more likely the nuts were to contain a substance that indicated oxidation. Studies have shown that when nuts are roasted at a low-to-medium temperature, their fats are less likely to go bad. The key is to regulate the cooking temperature and time. Luckily, you can reduce the formation of these free radicals by controlling the roasting process. Oxidized fat, or rancid fat, is responsible for the “off” taste and smell in some nuts. This can lead to the formation of harmful free radicals, which can damage your cells.
When polyunsaturated fats are exposed to heat, as is the case with roasting, they’re more likely to become damaged or oxidized. High Temperatures and Long Cooking Times Have the Greatest Impact These healthy fats have the ability to lower blood cholesterol and may protect against heart disease ( 18). Nuts are high in monounsaturated and polyunsaturated fats. Summary: Raw, dry-roasted and oil-roasted nuts all contain very similar amounts of calories, fat, carbs and protein. That’s because nuts are naturally high in fat and cannot absorb much more of it from added fat ( 16, 17). Nevertheless, roasted nuts can be slightly higher or lower in these macronutrients, depending on the type of nut ( 15).Ĭontrary to what you might expect, oil-roasted nuts are only slightly higher in fat and calories than dry-roasted nuts. Meanwhile, the protein and carb contents of raw and roasted nuts are very similar. However, the polyunsaturated fats in roasted nuts become more susceptible to oxidation, as the structure of the nut changes ( 7, 13, 14).
Some studies have shown that roasting nuts does not change the overall fat content. That explains why the fat content per ounce is slightly higher in roasted nuts ( 12). Therefore, a roasted nut weighs less than a raw nut. Similarly, 1 ounce (28 grams) of raw pecans contains 193 calories and 20 grams of fat, but the same amount of dry-roasted pecans contains 199 calories and 21 grams of fat ( 10, 11).ĭuring roasting, nuts lose some moisture. One ounce (28 grams) of raw almonds contains 161 calories and 14 grams of fat, whereas the same amount of dry-roasted almonds contains 167 calories and 15 grams of fat ( 8, 9). Although, roasted nuts have slightly more fat and calories per gram, but the difference is minimal. Raw and dry-roasted nuts have very similar amounts of fat, carbs and protein. Specifically, it changes their color and decreases their moisture content, giving rise to their crunchy texture ( 5, 7). Roasting nuts changes their structure and chemical composition.
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