Monthly Archives: December 2016

The chemistry of healthy cooking oils

The use of plant oils rather than lard, butter and other animal-based fats universally eliminates the saturated fat that we would otherwise consume. The way that the human body processes saturated fats ends up forcing the body to build its own low-density cholesterol, so avoiding these types of fats is an exceptionally good idea. With this in mind, not all plants are created equal. Neither are the various oils made by pressing these plants.

Vegetable and plant oils are liquid at room temperature, because unsaturated fats have a lower melting point than saturated fats. The reason for this is chemical. Saturated fat is called saturated, because every carbon-carbon double bond along the spine of the fat molecule has had all of its double bonds removed and a number of hydrogen atoms added. Simply enough, it’s totally saturated with hydrogen. Though normally perfectly safe to consume, vegetable oils can be chemically converted to saturated fats through a process known as hydrogenation, literally the addition of hydrogen to the fat. If this process is done part way so that only some of the double bonds have been saturated, we end up with partially hydrogenated oils, also known as trans fats. Keep an eye out for hydrogenated and partially hydrogenated vegetable oils on the ingredient lists of foods. They’re just as bad as, if not worse than, animal fats.

Smoke Points and Flavor: The Heart of the Cooking Oil Search

When purchasing straight plant oils, there are two primary factors to consider. First, every oil will taste different. Second, each oil has a different smoke point, the temperature at which theoil will begin to smoke, sputter and denature into something decidedly less than delicious. These two properties influence how each oil is to be used.

A number of popular oils, a description of their flavors, and their smoke points are listed below.

  • Best used when stir frying, almond oil tastes much like the parent nut. Its smoke point is at approximately 420°F.
  • Similar in flavor to olive oil, avocado oil is best used in stir frying, searing and other applications that require a high temperature. With a smoke point of 520°F, avocado oil is among the most robust plant oils on the planet.
  • Olive oil has a rich, light-bodied taste and has a wide range of applications due to the pressing system placed upon the oil. Extra virgin olive oil has a smoke point of about 320°F, while progressive pressings each have a higher smoke point than the one before it. For its part, extra light olive oil has a smoke point of 468°F.
  • Sesame oil has two styles: a light and nutty Middle Eastern variety and a dark and toasted Asian variety. Though a tasty addition to any skillet cooking up meats, it is also a superlative salad dressing base. Its smoke point is at 410°F.

The various cooking oils present on the market each have their own quirks working for them. Varying flavors, smoke points and fat profiles bring about a myriad of uses that the savvy consumer should always stay abreast of.

Bear in mind, however, that plant oils can be corrupted by modern industrial processes. Partially hydrogenated and hydrogenated vegetable oils are, in the end, no better for the consumer than animal fats and defeat the purpose of plant oils in the first place. By applying due diligence, however, the savvy consumer can enjoy these various oils without sacrificing health to do it.

Cooking blueberries decreases their polyphenol content

Polyphenols, the plant compounds that exhibit various cell-protective, antioxidant properties, can be found throughout nature, including in foods such as honey, broccoli and blueberries, to name a few.

Polyphenols comprise over 4,000 distinct species and can have a positive impact on cell-to-cell signaling, enzyme activity, receptor sensitivity and gene regulation. Scientifically, polyphenols are compounds that contain more than one phenolic hydroxyl group. This chemical structure equips them with free radical scavenging properties and the ability to upregulate certain metal-chelating reactions. Yes, some polyphenols help the body naturally detoxify from certain heavy metals.

Polyphenols, which give a boost to men and women’s cellular health, are naturally weaved into the environment. A new study from the American Chemical Society shows how essential polyphenol content is significantly reduced in natural foods like blueberries when they are cooked. This is important, because many people may think that they are eating a healthy snack, but they may not be getting the whole plethora of antioxidant benefits. Blueberry juice, baked blueberry pie or blueberry muffins can have drastically reduced antioxidant properties when compared to freshly picked, uncooked, wild blueberries.

Blueberry’s superfood powers reduced when cooked

Blueberries are high in polyphenols, including anthocyanin, which gives blueberries their blue color. Other flavonoids, like procyanidin, give blueberries their cellular regenerative properties. Quercetin gives blueberries anti-inflammatory properties, while other phenolic acids make blueberries an anti-aging powerhouse food.

These polyphenols travel into the human body and improve thinking, blood pressure and inflammation, but these benefits can be negated through certain cooking methods. For starters, certain processed blueberry drinks show reduced polyphenol content from anywhere between 22 and 81 percent.

Ana Rodriguez Mateos and fellow colleagues from the American Chemical Society sought to test the loss of polyphenol content of blueberries during the baking process, especially in cooked breads, muffins and pies. They measured the polyphenol content of the baked goods during the time when the dough rises.

What they found was that certain important polyphenol levels declined, including anthocyanin and procyanidin levels. Anthocyanin levels fell by up to 21 percent. The largest procyanidin oligomer levels dropped dramatically as well. While quercetin levels remained about the same, some phenolic acid levels increased.

Another study shows anthocyanidin degradation in cooked blueberries

Another study from Portugal examined anthocyanin and anthocyanidin composition of blueberries when cooked in stuffed fish. Three wild cultivations of blueberries were studied, including bluecrop, bluetravel and ozarkblue. 13 anthocyanins were extracted following the cooking process, and these polyphenols were separated in methanolic extracts of raw fruits. The researchers examined the polyphenols using liquid chromatography and diode array detectors.

What they found was that progressive heating of blueberries, from 12 to 99 degrees Celsius, decreases anthocyanidin and anthocyanin content. In a 60-minute heating session, polyphenol content fell between 16 and 30 percent in the blue crop variety, 30 to 42 percentfor bluetravel, and 12 to 41 percent for Ozarkblue. Despite the loss, the researchers saw no change in free radical scavenging activity, suggesting that other antioxidant levels may increase during the cooking process.

Not all is lost in the cooking process

Not all antioxidant powers are lost during the cooking process, these studies suggest. The Portuguese scientists recommend cooked blueberries right along with fresh wild blueberries for a healthy dose of dietary polyphenol antioxidants. It seems that, while cooking reduces certain polyphenol levels, other antioxidant levels may actually increase.

That’s what the American Chemical Society study found. The baked blueberries showed increased levels of a smaller variety of procyanidin oligomers. The researchers also found that yeast helped stabilize the blueberries’ polyphenol content through the baking process.

New hemp plants bred to have increased oleic acid

Scientists have found a way to make hemp produce 70 percent more oleic acid, making the crop more viable as a source for cooking oil and other industrial purposes.

Scientists breed hemp to increase its monounsaturated oleic acid content

The scientists, from the University of York, used fast-track molecular plant breeding, selected hemp plants that lacked the active enzyme responsible for creating polyunsaturated fatty acids. Instead, they used varieties that accumulate higher levels of monounsaturated oleic acid. The plant-breeding research is published in the journal Plant Biotechnology and outlines techniques to develop hemp plant breeds deemed “High oleic Hemp,” which could be introduced commercially as an attractive break crop for cereal farmers.

This new cooking oil could possess a longer shelf life with greater heat tolerance and be similar to olive oil in oleic acid content, making it suitable for many more industrial applications.

The new “High oleic Hemp” is 80 percent oleic acid, which trumps regular hemp oils containing just 10 percent. This will give the oil more thermal stability that is five times greater than normal, natural hemp oil. The new hemp oil could be more useful in high-temperature industrial processes.

Breeding hemp in this way limits other key components of the plant

As the agricultural sector looks to finally embrace valuable hemp farming, they will do so using a select, scientifically established breed of hemp. The natural composition of hemp, producing 80 percent polyunsaturated fat, hass the most polyunsaturated fat among vegetable seed oils known in the plant kingdom. The new agricultural breeding process will reverse all that. The new high-oleic hemp breed will provide increased oleic acid content that stems from breeding techniques that help the hemp plant produce more omega-9 fatty acids. This will alter the plant’s properties, limiting its composition of beneficial polyunsaturated fats.

As scientists breed hemp varieties without polyunsaturated fat content, the overall value of the plant for human health is rearranged. With its increased oleic acid content, it may be good for industrial purposes, but this increase in oleic acid content steers the plant away from producing other key offerings. One of the sacrifices includes the loss of polyunsaturated fats, which means that essential fatty acids like omega-3 and omega-6 acids could be limited. These fatty acids are not produced by the body but are needed, especially for cell membrane production. They also are used to produce prostaglandin, which aids the body’s inflammatory functions. The change may be insignificant, however, since humans rarely receive beneficial omega-9 fatty acids, which will be increased in the new breed.

Europe to welcome “High oleic Hemp” in 2014 field tests

The new “High oleic Hemp” will be openly welcomed in the UK, where farming of oilseed rape has declined recently due to pests and disease. To maintain cereal yields, the UK and other European countries may embrace the “High oleic Hemp” as a quality oil alternative.

With its many other uses, hemp will be a great crop choice for farmers. The hemp straw can alternatively be used as fiber for composites, bedding, wax, biomass and textiles.

“The new line represents a major improvement in hemp as an oil crop. Similar developments in soybean and oilseed rape have opened up new markets for these crops, due to the perceived healthiness and increased stability of their oil,” says Professor Ian Graham, from York University’s Centre for Novel Agricultural Products Biology Department.

The “High oleic Hemp” is set to be planted in 2014 throughout Europe, as field trials launch a new era of farming. This may be good news for agriculture, industry and cooking processes for people around the world.

It won’t be long before agriculturally suppressed countries like the USA begin farming hemp for a variety of purposes as well.

Increased hemp production is a suitable fit for a world looking to sustain itself.

Tips to avoid inadvertently poisoning your food

When it comes to cooking at home, most health-conscious folks would probably say that their aim is to prepare wholesome, savory meals in the cleanest way possible for their families. However, unless these foods are cooked properly at the right temperatures and for the appropriate lengths of time, they could still be harmful to your health even if they are organic.

In addition to the more obvious precautions such as choosing only chemical-free produce and pasture-raised meats and cooking with only healthy saturated fats at higher heat, home cooks also need to pay attention to the ways in which they cook these foods. Certain foods — carbohydrates in particular — can release toxins when they are cooked at too high of a temperature or for too long.

When cooked improperly, potatoes are one such food that can generate a poisonous substance known as acrylamide that animal studies have shown can cause cancer. This white, odorless, water-soluble chemical is generated when starchy foods are cooked at temperatures higher than 250 degrees Fahrenheit or 121 degrees Celsius. Potatoes (including sweet potatoes), grains, and even coffee all generate acrylamide during cooking and/or roasting.

Temperature is not the only thing that matters; cooking time is also an important consideration. For example, when potatoes are cooked above the aforementioned temperature threshold, they continue to progressively produce more acrylamide the longer they are cooked. For this reason, it is important for home cooks to pay attention to both temperature and cooking duration when preparing food for their families at home.

Why is acrylamide so bad for your health? Here’s what The Healthy Home Economist‘s Sarah Pope has to say on the matter, referencing published science:

“Rats and mice fed high levels of [acrylamide] in their drinking water were found by researchers to be at increased risk for several types of cancer. In people, studies on acrylamide in the diet have produced mixed results for some types of cancer including kidney, endometrial, and ovarian. Exposure to high levels of acrylamide in the workplace via inhalation or the skin has been shown to cause nerve damage, which can lead to numbness or weakness in the arms or legs, bladder problems, in addition to other symptoms.”

Take these steps to minimize acrylamide formation when cooking at home

Acrylamide is clearly something we all want to avoid, but what is the best way to accomplish this? The first and most obvious way is to cook starchy foods at 250 degrees F or less whenever possible, paying close attention to the color of foods as they cook. Try to keep browning — and charring in particular — to a minimum. You should aim for a light, golden brown color.

Another easy way to minimize acrylamide formation in carbohydrate foods is to blanch them in boiling water for a few minutes prior to frying, baking, or broiling. You can soakpotatoes in cold water for 15 to 30 minutes prior to cooking; make sure to drain the water and blot them dry before exposing them to hot oils and fats so they don’t splash and cause burns or fires.

Even when you use healthy oils like coconut and palm or healthy fats like lard and ghee, acrylamide will continue to form the longer a food is cooked. Therefore, you should keep cooking time to a minimum, allowing for just enough heat exposure to produce the desired end product. When cooking is complete, dry the cooked foods in a hot air oven for a few minutes to decrease acrylamide content.

Don’t store potatoes in your refrigerator, and never eat sprouted potatoes

Normally when we think of sprouted foods, the implication is that they’re always healthier and more nutritious than their non-sprouted counterparts. In the case of potatoes, however, the exact opposite is true. When potatoes sprout, they produce a toxic substance known as solanine that has been shown to trigger gastrointestinal and neurological problems when ingested.

To avoid this, always store your potatoes in a dark, cool place where they are not exposed to the light. It is also important to avoid storing potatoes in your refrigeratorbecause this actually increases the amount of acrylamide produced when those potatoes are later cooked.

High-heat cooking can also produce other dangerous and potentially carcinogenic compounds, such as heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs), as well as advanced glycation end products (AGEs). Like acrylamide, these substances result from the chemical reactions of various creatines and amino acids that are produced during the cooking process.

Both HCAs and PAHs are recognized cancer-causing agents and are likely the very reason that meats, for example, have been vilified in recent years as potentially causing cancer. It isn’t necessarily the meats themselves that are causing cancer, but rather the way these meats are procured and served — at high heat and often charred.

“Opt for slower, indirect-heat methods of cooking such as poaching, stewing, braising, or steaming,” the group Precision Nutrition suggests. They also recommend that home cooks:

• Cook foods at lower temperatures
• Avoid charring or burning foods
• Avoid cooking any processed foods, which tend to contain high levels of damaging AGEs
• Use liquid in cooking (such as with braising)
• Use acids like lemon juice or vinegar in marinades, which help decrease the formation of toxins like AGEs