The World's Healthiest Foods are health-promoting foods that can change your life.

Try the exciting new recipe from Day 1 of our upcoming 7-Day Meal Plan.

The George Mateljan Foundation is a not-for-profit foundation with no commercial interests or
advertising. Our mission is to help you eat and cook the healthiest way for optimal health.
What Is the best way to roast nuts and seeds?

Based on the research studies that we have reviewed about different ways of roasting nuts and seeds, we would start out by saying that there does not appear to be any magical best way of roasting the foods in this amazing food group. Even though nuts and seeds tend to be similar in terms of their total protein, total fiber, and total fat content, their overall nutrient composition is actually quite diverse, and so they can be impacted quite differently by varying roasting temperatures and times.

As a general rule, the most nutrient-rich form for nuts and seeds is their raw form. Provided that your nuts and seeds are high-quality and correctly stored, you are going to get the greatest concentration of nutrients from this raw form. And in keeping with this principle, you will notice that we used nutritional data for raw nuts and seeds whenever possible on our website. (In some cases where good data on raw nuts and seeds was lacking, we did use the dried form for these foods.)

However, we also recognize that raw nuts and seeds may lack many of the delicious flavors and aromas that can be created through roasting. For this reason, we realize that many people will be more likely to take advantage of the nutrient richness found in this food group if their nuts and seeds have been roasted.

Home Roasting versus Commercial Roasting

Unless you are confident in the roasting methods used with a commercially roasted product, we recommend the home roasting of raw nuts and seeds if you prefer not to consume them in raw form. We make this very general recommendation for two reasons. First, it can be difficult to find dry roasted versions of some nuts and seeds, and the added oil required for oil-roasting can be more susceptible to heat damage than fats that are naturally present within the nuts and seeds. As whole natural foods, nuts and seeds have their own natural protective factors and these factors help protect their fats from damage by heat and other factors. By contrast, processed added oils may not have any natural sources of protection from heat. Second, even when dry roasted nuts and seeds are available, it can be difficult or impossible to determine the temperature used in roasting.

Roasting Temperatures

Commercial roasters of nuts and seeds typically follow HACCP (Hazard Analysis Critical Control Points) safety guidelines for roasting as established through the combined efforts of the, U.S. Department of Agriculture, U.S. Food and Drug Administration and Centers for Disease Control and Prevention, and Department of Health and Human Services. Minimum roasting temperature guidelines are generally based on Salmonella heat resistance values and range from 248°F-284°F. However, we recognize that home roasting is different, and we haven't come across any comparable government recommendations for home roasting temperatures. Nor have we come across any evidence to show that different levels of safety are associated with home roasting at different temperatures.

As a general rule, research studies do not show large nutrient changes in association with roasting temperatures 300°F and below. Most of the nutrient changes that we have seen with roasting temperatures between 160°F and 300°F involve—at most—10-20% loss of select nutrients. There are some mixed findings involving certain phytonutrient changes within this roasting range. Also, in some cases, nutrient loss appears to fall into this same range even when roasting takes place at higher temperatures. Based on this general research review, we believe that you can get strong nutritional value from nuts and seeds when using home roasting methods based on this general temperature range of 160°F-300°F.

Roasting and Fat Quality

One aspect of nut and seed roasting of special interest to many people is possible damage to their fat quality when roasting. As a general rule, nuts and seeds are more stable to heat than might be expected given their high fat content. (About 75-80% of the calories found in nuts and seeds come from fat.) This greater-than-expected stability is most likely related to their relatively high percentage of monounsaturated versus polyunsaturated fats. Nuts like cashews and almonds contain 2-4 times as much monounsaturated as polyunsaturated fat, and of these two fat types, monounsaturated fat is less susceptible to damage by heat and other factors. Less susceptible still is saturated fat, whose amount is roughly equivalent to the amount of polyunsaturated fat in cashews and about 33-50% of the polyunsaturated fat level found in peanuts, pumpkin seeds, and sesame seeds. These relatively high levels of monounsaturated and saturated fat help support the overall stability of fat content in nuts and seeds.

Two clear exceptions to this rule would be flaxseeds and walnuts. Both of these foods contain more polyunsaturated fat than any other fat type, as well as high levels of omega-3 polyunsaturated fat. Within all of our eight nuts and seeds, we would single out these two foods as being especially important to protect from heat damage. If not being consumed in raw form, you may want to consider roasting these two particular foods at lower temperatures and/or for shorter periods of time.

Length of Roasting Times

Almost all of the studies that we reviewed analyzed roasting times between 10-60 minutes. Based on our own experience with flavors, aromas, texture, and taste, we cannot find any reason to roast at the maximum end of this time period. In keeping with our general WHFoods approach of minimal cooking times with delicious results, we recommend roasting times of approximately 10-20 minutes rather than longer time periods.

Cookware for Roasting

We recommend the use of an ungreased stainless steel baking sheet or cast iron cookware for nut and seed roasting. In either case, you will want to create a single layer of nuts or seeds to allow for more uniform air flow around each nut or seed. It is fine to open the oven a few times and shake the nuts or seeds a little bit in order to reposition them slightly and promote more uniform roasting. Just make sure to wear an oven mitt to protect your hand and forearm.

Shelf Life of Roasted Nuts and Seeds

While raw nuts and seeds can usually be stored in tightly-sealed containers in your refrigerator for months-long periods of time, we do not recommend this same approach to home-roasted nuts and seeds. Instead, we recommend the roasting of small amounts of nuts and seeds that you plan to consume over the next couple of days. This recommendation is based on our desire to err on the side of caution with the more delicate nutrient composition of roasted nuts and seeds. Continue to keep your roasted nuts and seeds tightly sealed in the refrigerator, even when planning to enjoy them within a relatively short period of time.

Checking Oven Temperatures

To ensure you are actually cooking at the temperature you have chosen, we suggest that you check the accuracy of the temperature gauge on your oven. This check can easily be done with an inexpensive oven thermometer. You can find an oven thermometer at any hardware or kitchen store, or even the kitchen equipment aisle of your grocery store. Look for a stainless steel, spring-operated dial type that has both a flat bottom for standing and a hook for hanging on the rung of an oven shelf. The cost is typically $5 to $12.

To test your oven, place the thermometer on a center rack, preheat the oven for 15 minutes and then compare the reading on the thermometer to your oven gauge. If it is higher or lower than what your oven gauge indicates, then you know that your oven tends to run either hot or cold and can compensate. For instance, if your gauge reads 170°F, but the thermometer reads 200°F, you know that your oven tends to run 30 degrees hot, and you can adjust the temperature downward to 140°F to compensate.

References

  • Barros AIRNA, Nunes FM, Goncalves B et al. Effect of cooking on total vitamin C contents and antioxidant activity of sweet chestnuts (Castanea sativa Mill.). Food Chemistry, Volume 128, Issue 1, 1 September 2011, Pages 165-172.
  • Bolling BW, Blumberg JB and Chen CYO. The influence of roasting, pasteurisation, and storage on the polyphenol content and antioxidant capacity of California almond skins. Food Chemistry, Volume 123, Issue 4, 15 December 2010, Pages 1040-1047.
  • Chandrasekara N and Shahidi F. Antioxidative potential of cashew phenolics in food and biological model systems as affected by roasting. Food Chemistry, Volume 129, Issue 4, 15 December 2011, Pages 1388-1396.
  • Galvao MF, Cabral Tde M, de Andre PA, et al. Cashew nut roasting: chemical characterization of particulate matter and genotocixity analysis. Environ Res. 2014 May;131:145-52. doi: 10.1016/j.envres.2014.03.013. Epub 2014 Apr 11.
  • Gerstenmeyer E, Reimer S, Berghofer E, et al. Effect of thermal heating on some lignans in flax seeds, sesame seeds and rye. Food Chemistry, Volume 138, Issues 2—3, 1 June 2013, Pages 1847-1855.
  • Grocery Manufacturers Association. (2010). Industry Handbook for Safe Processing of Nuts. GMA Nut Safety Task Force, Grocery Manufacturers Association, Washington, DC.
  • Lemos MRB, Siqueira, EM de A, Arruda SF, et al. The effect of roasting on the phenolic compounds and antioxidant potential of baru nuts [Dipteryx alata Vog.]. Food Research International, Volume 48, Issue 2, October 2012, Pages 592-597.
  • Rodrigues AC, Stroher GL, Freitas AR et al. The effect of genotype and roasting on the fatty acid composition of peanuts. Food Research International, Volume 44, Issue 1, January 2011, Pages 187-192.
  • Roman O, Heyd B, Broyart B, et al. Oxidative reactivity of unsaturated fatty acids from sunflower, high oleic sunflower and rapeseed oils subjected to heat treatment, under controlled conditions. LWT - Food Science and Technology, Volume 52, Issue 1, June 2013, Pages 49-59.
  • Tsantili E, Konstantinidis K, Christopoulos MV et al. Total phenolics and flavonoids and total antioxidant capacity in pistachio (Pistachia vera L.) nuts in relation to cultivars and storage conditions. Scientia Horticulturae, Volume 129, Issue 4, 27 July 2011, Pages 694-701.
  • Wall MM and Gentry TS. Carbohydrate composition and color development during drying and roasting of macadamia nuts (Macadamia integrifolia). LWT - Food Science and Technology, Volume 40, Issue 4, May 2007, Pages 587-593.
  • Yoshida H, Hirakawa Y, and Abe S. Roasting influences on molecular species of triacylglycerols in sunflower seeds (Helianthus annuus L.). Food Research International, Volume 34, Issue 7, 2001, Pages 613-619.

Printer friendly version

Send this page to a friend...

rss


Newsletter SignUp

Your Email:

Find Out What Foods You Should Eat This Week

Also find out about the recipe, nutrient and hot topic of the week on our home page.

 

Everything you want to know about healthy eating and cooking from our new book.
2nd Edition
Order this Incredible 2nd Edition at the same low price of $39.95 and also get 2 FREE gifts valued at $51.95. Read more


Healthy Eating
Healthy Cooking
Nutrients from Food
Website Articles
Community
Privacy Policy and Visitor Agreement
References
For education only, consult a healthcare practitioner for any health problems.

We're Number 1
in the World!

35 million visitors per year.
The World's Healthiest Foods website is a leading source of information and expert on the Healthiest Way of Eating and Cooking. It's one of the most visited website on the internet when it comes to "Healthiest Foods" and "Healthiest Recipes" and comes up #1 on a Google search for these phrases.

Over 100 Quick &
Easy Recipes

Our Recipe Assistant will help you find the recipe that suits your personal needs. The majority of recipes we offer can be both prepared and cooked in 20 minutes or less from start to finish; a whole meal can be prepared in 30 minutes. A number of them can also be prepared ahead of time and enjoyed later.

World's Healthiest
Foods
is expanded

What's in our new book:
  • 180 more pages
  • Smart Menu
  • Nutrient-Rich Cooking
  • 300 New Recipes
  • New Nutrient Articles and Profiles
  • New Photos and Design
privacy policy and visitor agreement | who we are | site map | what's new
For education only, consult a healthcare practitioner for any health problems.
© 2001-2017 The George Mateljan Foundation, All Rights Reserved