Content And Background Knowledge
What is a Physical change?
Physical change is when matter is altered by appearance or form, but the chemical components remain unaltered. The molecules remain the same before and after because the chemical bond does not break nor is a new substance created. Appearance such as shape, color, density, and volume may change without a chemical reaction. One example is with a clove of garlic. The garlic clove can be chopped, sliced, smashed and minced; the matter is still the same despite the change in shape. Another example is paper. Paper can be cut and crumbled, which only changes the form. This is a good example of reversible change, because the sheet of crumpled paper becomes a sheet of paper again. Reversible change does not always happen. For example, when garlic is minced, it cannot be shaped back into a clove or when a log is cut, it cannot be put back together. The most popular physical change to teach beginners is about water. Freezing water into cube trays to make ice cubes transforms liquid into solid which may turn back into liquid through the process of melting. Adolescents enjoy playing with clay. They take a piece of clay and squeeze it from hand to hand. By doing this, the clay softens, which becomes easier to mold into a shape, but only the shape and texture change. When the clay is stored back into its container, the texture and shape changes back to its original form. A phase change occurs with altered temperature or pressure. From the website, Physical Changes in Chemistry. – ThoughtCo. August 5, 2024. (viewed 7-13-2026), one learns that a mixture that involves “mixing together materials where one is not soluble in the other is physical change. Note the properties of a mixture may be different from its components.”[1] An example of a mixture is blending sugar and water. The sugar will dissolve. When boiled, the molecules will separate, and the sugar will form at the bottom. Another example of physical change is mixing bread ingredients. For Fried Bread, you mix in flour, salt, baking powder and water until it becomes a soft dough. The substances used in the dough do not change their chemical composition.
While attending the YNI 2026 seminar, we discussed how a physical change in cooking is identified. Melting butter, turns the butter into a liquid. Chopping tomatoes for dirty spaghetti, changed the size. For both of these changes, the substances stay the same. We made salad dressing by mixing vinegar with oils, which are not soluble. We were able to observe the separation of substances when we let the jar sit. The heavier substance will usually stay at the bottom of the container.
What is a Chemical change?
A chemical change occurs when one substance is changed into a new substance due to an energy change through light, sound or heat (combustion). The atoms break the old bonds and make new bonds. Another chemical change that may occur is the change in color (wood is brown but after burned will turn black or grey). Gas and odor may be formed during a chemical change (when baking a cake for example, the aroma is present when it is almost done). Chemical changes are irreversible, meaning, they cannot be undone. A new substance takes the place of the original substance. Atoms break apart, creating a new bonds. Some signs of a chemical change are the change in color, it may produce an odor (aroma), it may absorb or release heat, it may release gas and it may produce light and/or sound. Wild plants that grow outside will convert carbon dioxide and water into glucose and oxygen by using sunlight through light energy, from the website, Chemical Change Definition in Chemistry, - ThoughtCo. August 2, 2024 (viewed August 8, 2026).
KEY TAKEAWAYS: CHEMICAL CHANGE[2]
- A chemical change occurs when one substance is transformed into one or more new products via a chemical reaction.
- In a chemical change, the number and type of atoms remain constant, but their arrangement is altered.
- Most chemical changes are not reversible, except via another chemical reaction.
At the YNI 2026 seminar, we witnessed chemical changes in cooking. Popping popcorn is considered a physical change; however, for it to be classified as a chemical change, the popcorn will need to be burnt. In the seminar, pizza dough was made and fried over hot oil. The Maillard reaction gave the dough a delicious smell when it was done.
What is the Maillard Reaction
From the website, Maillard Reaction – ScienceDirect. 2016: “The Maillard reaction is a cascade of reactions initiated by the condensation reaction of an amino group with the carbonyl group of reducing sugar. In dairy systems, these are primarily the amino groups of lysine and arginine as well as N-terminal amino groups of proteins and peptides while the reducing sugar is lactose (or glucose and galactose in lactose hydrolysed products).” The Maillard reaction is responsible for browning like burnt, charred, toasted are some examples. From the website, Serious Eats. May 13, 2023: “The Maillard reaction is many small, simultaneous chemical reactions that occurs when proteins and sugars in and on your food are transformed by heat, producing new flavors, aromas, and colors.”[3] We have smell and taste receptors that humans rely on when going out to eat. The aroma of bread baking or meat grilling or coffee brewing entices us to choose what we chose to consume. Beer also goes through the Maillard reaction; the grains are roasted before it is brewed. The heat is the first process in the Maillard reaction, at least above 300 degrees Fahrenheit to cook meat. When baking/frying bread, the dough is white and after cooked, the bread turns a golden to brown color. Meat is raw and red in color, when grilled the meat becomes a dark brown to black color and the aroma is present. People love to eat potatoes. Sure, you can eat it raw, but it will take longer to digest due to the high starch. Roasting potatoes releases nutrients and breaks down the starch so our bodies are able to absorb it. The browning on the outer potato is due to the Maillard reaction. Boiled and steamed potatoes do not go through the Maillard reaction.
What is Lye?
Originating from Old English “ley”, meaning ash water solution, lye is an alkaline chemical, which breaks down two types of molecular bonds. The ester bond holds the fats together and the amide bonds hold the protein together. To make lye, certain types of wood are burned for its ash, such as oak, maple, hickory and birch. Since the early 1800’s, people have modified ways to make lye. Early Native Americans would burn oak or hickory wood into ash. Using a hand-woven basket as a filter, they would then slowly pour rainwater over the ashes. In modern times, water is boiled while using plastic buckets. At the end of the process, you will have an amber to yellowish liquid, this is lye.
NaOH, sodium hydroxide, is what is used to make hard bar soaps from fat. You must follow safety precautions when making soap. From the website What is Lye? All you need to know! - Bee Clean Soaps. May 25, 2022 (viewed 7-25-26), one learns that “Like other corrosive acids and alkali’s, sodium hydroxide in solution form can dissolve proteins quickly and lead to moderate to severe chemical burning when exposed to skin.”[4]
Today, lye is used in shampoo, laundry detergent and some household cleaning products because it is an alkaline chemical. Through saponification, lye transforms fats and oils into soap through chemical reaction. Soap will need to sit or cure for it to become hard and at this time, the lye is neutralized so the soap bar is now safe.
The history of corn and what makes it color
The first corn or maize to be introduced in America came from Mexico around 10,000 years ago. The Indigenous people that migrated North brought the corn seed with them. The Natives found ways to store corn during the winter months by drying the kernels. During the winter months, they used the dried corn to make hominy soup and ground them into a powder form. With this, they made bread, syrup or puddings. Husks of the corn were made into baskets, sleeping mats or masks. In modern times, corn husks are used to roll mountain tobacco to smoke during traditional ceremonies.
The Three Sisters
Predominately planted by Native Americans, three different seeds are planted together. Corn, beans, and squash are compatible, helping each other survive and flourish. As the corn grows, the bean grows around the corn stalk leaving more space for the squash at the bottom. The bean enriches the soil that feeds the corn and squash. The squash grows around the ground, protecting the soil from the sun and keeps weeds from growing. The leaves and stems of the squash are prickly, keeping certain animals from chewing at the crop. From the website The Three Sisters of Indigenous American Agriculture – USDA National Agricultural Library one learns “The milpa system is the classic example of an efficient multi/mixed cropping system, which tends to be more productive and efficient in use of light, nutrients and water than monocrop systems, given its internal dynamics of complementarity, competition, and facilitation.”[5]
The macronutrient of corn is starch (carbohydrate), which is close to 75% of the dry weight and has natural sugars. Corn is very low in total fat. Corn has some plant-based protein. Essential vitamins and minerals include vitamin C, B vitamin, potassium, magnesium and phosphorus. Health benefits include support of the immune system, aid in cellular energy, maintaining blood pressure and being good for bone and nerve health. The macronutrient of bean has 40-45 grams of carbohydrates, less than 1 gram of fat and 15 grams of protein. Essential vitamins and minerals include folate, iron, potassium and magnesium. Health benefits of beans are support of blood pressure, muscle functions, digestion and heart health. The macronutrient of a cup of raw summer squash is 4 grams of carbohydrate, 0 gram of fats and 1 gram of protein. Essential vitamins and minerals are vitamin C and potassium. Health benefits for eating squash are to boost the immune system and support eye health, and it is low in calories.
Other U.S. traditional foods that are made from corn are corn bread and tortillas. You might wonder, why does corn grow in different colors? Most common colors for corn are white, yellow, blue, red, purple and black. The color comes from a pigment. One kind of pigment is called anthocyanin, this creates blue, red and purple kernels. Another kind of pigment is called carotenoid, which creates white, and yellow to orange colors. Mayan culture thrived off maize. It was a large part of their economic and religious characteristics. They traded maize with other tribes for resources or foods, such as fish.
Health benefits of blue corn
Blue corn is very rich in anthocyanins and is known for its antioxidant benefits. If you suffer from arthritis, diabetes or have low minerals, then blue corn is something to investigate. It should be used in moderation only. Blue corn is on the lower part of the glycemic index, so this helps regulate blood sugar. Its content is anti-inflammatory, so people with arthritis should take advantage of this. Lastly, blue corn is high in fiber and helps lower cholesterol levels and blood pressure, which is all good for heart health.
The History of Juniper Ash
According to the Tree Vitalize article, there are 25 types of Junipers in the U.S., and 67 types worldwide. Junipers survive in harsh surroundings, like around mountains, oceans, deserts and rock bluffs. They developed over 200 million years ago. In the article, Assessment of Juniper Ash Elemental Composition for Potential Use in a Traditional Indigenous Dietary Pattern one learns that “Juniper ash from the southwestern U.S. available for retail purchase was used for comparison. All samples were tested for content of 10 nutritive elements (Ca, copper, iron, potassium, magnesium, manganese, sodium, phosphorus, selenium, and zinc) and 20 potentially toxic elements (silver, aluminum, arsenic, barium, beryllium, cadmium, cobalt, chromium, mercury, lithium, molybdenum, nickel, lead, antimony, tin, strontium, thallium, uranium, and vanadium) as well as n = 576 pesticide residues.”[6]
The benefits of Juniper Ash
The Juniper tree branch will go through a chemical change, when it is burned by fire. Ash is used by a few members of the Indigenous tribes, Navajos being one of the tribes. Juniper ash has a natural source of calcium. In one teaspoon, there is 445 mg of calcium. This benefits people that are lactose-intolerant, mixing a small portion in water to drink. It’s equivalent to a glass of milk.[7] Calcium helps with bone health. Another benefit of health is supporting the digestive system. Hospitals in Arizona and Utah serve blue corn mush with the juniper ash to their heart patients.
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