Food ingredient technology Test 2

Buffering agent

1) a molecule that acts to maintain a steady pH of a system by either giving off to or accepting hydrogen ions from the surrounding medium.

List the three types of dispersions that make up food systems.

1. Solution (particles less than 1 nm in diameter) 2. Colloidal Dispersion (particles 10 -100 nm in diameter) 3. Suspension (large particles that remain suspended in the continuous phase)

Why do you believe it is important to use clarified butter, rather than plain butter, when making a brown roux?

1. The clarified butter has had the water and milk solids removed. If water is present, you will: a. begin to gelatinize the starch b. the temperature cannot get above the boiling point of water (212F) until all the water has boiled off, and c. The milk solids will begin to burn at high temperatures.

Describe the three major factors that are responsible for the stabilization of colloidal dispersions.

1. Water of Hydration 2. Net Similar Charges: There are similar net electric charges on the dispersed particles. 3. Brownian Movement

You have strawberry juice concentrate at 60 Brix and 10% total acidity and cranberry juice at 10 Brix and 1.5% total acidity. You are going to make 1000 grams of a juice beverage with a final Brix of 15. What is the final % total acidity of the new beverage?

10% TA stawberry concentrate x .1= 1 1.5% TA cranberry concentrate x .9= 1.35 Final total acidity = 2.35%

You have strawberry juice concentrate at 60 Brix and 10% total acidity and cranberry juice at 10 Brix and 1.5% total acidity. You are going to make 1000 grams of a juice beverage with a final Brix of 15. What is the BAR of the beverage?

15 brix/ 2.35 TA = 6.38

Enzymatic browning

A browning reaction that that does not involves an enzyme, oxygen, and a substrate (the molecule being broken down). An example is the browning of an apple when sliced open, the browning of avocado, pears, banana, potatoes. Enzymatic browning is also the browning that takes place when vanilla beans are fermented, or green tea is fermented into black tea. These reactions involve an enzyme and oxygen.

Non-enzymatic browning:

A browning reaction that that does not involves an enzyme: Maillard browning, caramelization, and dextrinization are all non-enzymatic browning reactions that take place at high temperatures, do not involve an enzyme, and result in 'brown' colors and flavors.

Sol-

A colloidal dispersion in a liquid, pourable condition. Smaller particles than a coarse suspension, but larger than the particles in solution suspended in a liquid.

Anion

A negative ion

Dextrinization:

A non-enzymatic browning reaction involving the breakdown of starches at high temperatures (greater that n 300F). Think of the browning of a roux.

Maillard Browning

A non-enzymatic browning reaction involving the breakdown of sugars and amino acids (the carbonyl group on a sugar and the amino group on an amino acid (building blocks of proteins) react and create brown colors and flavors. This reaction will take place at high temperatures (greater than 300F) when there are carbohydrates/sugars and proteins/amino acids present.

Cation

A positive ion

Shear-thinning

A rheological property of certain solutions and liquids where the viscosity appears to decrease as the shear increases. Also called pseudoplastic. While most gums form shear-thinning solutions, xanthan gum is an example of a highly shear-thinning gum. Example of sol'n that is not shear-thinning: sugar syrup

Centipoise

Abbreviated cP. Unit of measure of viscosity; higher cP means thicker liquid. The viscosity of water at room temp (68 F) is 1cP. Common viscometer in food industry that measures in cP units: Brookfield viscometer. Common equipment that does not: Bostwick consistometer.

1) List the food acids discussed in lecture and give an example of where each would be found in foods.

Acetic acid- Pickled veggies, flavor enhancer, ph control Lactic acid- Processed meats, snacks, dairy Malic acid- Apples, low alcoholic coolers.. enhance fruit flavors Fumeric acid- Fungus, tortilla bakery items.. Maintains dryness in powdered mixes Citric acid- in citrus (lemon, orange) Flavor enhancer. ph control Tartaric- Cream of tatar, grapes.. dough conditioner, leavening agent, flavor enhancer Phosphoric Acid- Cola, Acidulant and flavorant in colas and root beer at levels of Succinic Acid- Naturally occurring dicarboxylic acid found in most fruit and vegetables, bouillions, flavoring stocks, instant beverages

Describe the difference between the two fractions of starch

Amylose is a straight chain of glucose molecules linked together by chemical bonds. Amylose can be 100,000 + glucose units in length. Amylopectin is a branched chain of glucose molecule linked together by chemical bonds. Amylopectin can be up to 2Million glucose units in length. Amylose molecules can associate closer together than amylopectin molecules and will therefore form an opaque gel trapping liquid and other components inside the gel. Amylopectin, because of the branching, has the tendency to tangle with each other and creating more of a 'snotty' texture gel that is somewhat clear. Cereal starches have a higher level of amylose than do root starches, and therefore tend to create firmer opaque gels. Amylopectin is slightly more stable to heat, acid, shear and freezing than amylose. However, both as native starches are fragile the above treatments.

Oligosaccharide:

An intermediate size saccharide with 3 - 10 sugar units linked together with chemical bonds.

Monovalent

An ion with one charge (can be negative or positive)

Divalent

An ion with two charges (can be either positive or negative) A divalent cation is an ion with two positive charges and a divalent anion is an ion with two negative charges.

Pseudoplastic

Another word for Shear-thinning. It is a rheological property where as the shear force increases the mixture becomes thinner.

For an emulsifying agent to be effective, it must be:

Attracted to both water and oil

1) Which microorganism is responsible for the acid created during the fermentation of vegetables? What is the main acid created during the fermentation of vegetables?

Bacteria Several bacterial families are present in foods, the majority of which are concerned with food spoilage. As a result, the important role of bacteria in the fermentation of foods is often overlooked. The most important bacteria in desirable food fermentations are the lactobacillaceae which have the ability to produce lactic acid from carbohydrates. Other important bacteria, especially in the fermentation of fruits and vegetables, are the acetic acid producing acetobacter species

BAR stands for __________, which is an indicator of perceived sweetness/tartness of food product.

Brix Acid Ratio

_____is a molecule that acts to maintain a steady pH of a system by either giving off to or accepting hydrogen ions from the surrounding medium

Buffering agent

An example of a water-in-oil emulsion would be

Butter

Which of the following is not an organic leavening acid?

Citric acid

An emulsion is an example of:

Colloidal dispersion

1) Which of the four native starches discussed on slide 9 will give the firmest gel with an opaque appearance?

Cornstarch - it is higher in amylose.

Thermally reversible gel

Defines a gel that will melt upon heating. Taken from the Greek word thermos meaning heat and the Latin word reverses meaning to turn back, thermoreversible is a property of certain substances to be reversed when exposed to heat. Such substances form a gel when cooled and return to a viscous fluid state when exposed to heat. Gelatin, agar agar, and carrageenan are all examples of a thermally reversible gel.

Starch in a sol is the

Dispersed phase

Give specific examples of molecules that have emulsifying properties.

Egg yolk will give great permanent emulsions because they have Lecithin, a phospholipid that has a hydrophilic part and a hydrophobic part - which will create a stable emulsion. Mono and di glycerides, found in heavy cream, will also work nicely. But particles like spices, or small pieces of onion or garlic can also act to help emulsify.

Which organic acid is normally used to keep powdered mixes from caking due to the non-hygroscopicity?

Fumaric acid

Foam-

Gas dispersed in a liquid or solid. A stable mass of bubbles. All foams consist of tiny air pockets of air (carbon dioxide in the case of beer foam), surrounded by a thin film of water with various substances dissolved in it.

A thickened starch mixture that no longer flows is called a:

Gel

Colloidal dispersions are stabilized by..

Gel Coagulum Gum Precipitate

Explain the difference between high methoxy and low methoxy pectin in gelation

High methoxy pectin has a lot of methyl groups (CH3) that attract to each other by Van der Waals attractive forces. High methoxy pectin is the form of pectin that occurs naturally in plant cell walls and middle lamella. Low methoxy pectin has less methyl groups and more dissociated carboxylic acids (-COO- ). There are so many of these (-COO-) that calcium (a divalent cation) can pull these two pectins together just like it will pull the alginate together.

Saturation point of a solution

Highest concentration that can dissolve in water at room temperature.

The naturally occurring organic acid, found in many fermented foods (such as yogurt, cheese, and kefir) is ________.

Lactic acid

Give suggestions on how to stabilize a foam-

One suggestion to stabilize a foam would be to add egg white powder to juice and whip.

Gel-

Polymers or small solid particles forming a network that traps liquids. The sol, under proper conditions of temperature, pH, and concentration, may be transformed from a pourable mixture into a somewhat rigid solid called a gel.

You are making a soup and want it to give a rich creamy mouthfeel. Choose a native starch that you believe is best suited for the soup and clearly describe why.

Potato starch is a good choice. It has the largest granule of all the starches used in the culinary kitchen. When swollen it gives a creamy mouthfeel

A thickened (gelatinized) starch mixture that has flow properties is called a:

Sol

Which of the following has the smallest particle size solute?

Solution

You have strawberry juice concentrate at 60 Brix and 10% total acidity and cranberry juice at 10 Brix and 1.5% total acidity. You are going to make 1000 grams of a juice beverage with a final Brix of 15. How many grams of each ingredient do you need? [a] grams of strawberry juice concentrate[b] grams of cranberry juice

Specified Answer for: a 100 Specified Answer for: b 900

Describe the process of starch gelatinization - illustrate your description with a clear drawing

Starch gelatinization is the process of cooking starch granules in water, which allows the granules to swell and increase viscosity of the system.

Starch slurry is considered as a ______.

Suspension

As a secondary antioxidant, ascorbic acid could enhance the antioxidant action of primary antioxidants such as tocopherols, therefore, it is called ______

Synergist

Which organic acid is first isolated from cream of tartar (wine stone)?

Tartaric acid

Supersaturated solution

The particles are still less than 1 nm in diameter dissolved in a medium, however, there is more solute dissolved in the solution than what we know as the saturation point (highest concentration that can dissolve in water at room temperature).

Describe Syneresis.

The process of a gel contracting and squeezing out liquid. Weeping occurs during syneresis of a starch gel.

Why do you believe that coffee and cocoa roasters keep their roasting process proprietary?

The roasting process is directly related to the flavors that develop in the Maillard browning process during coffee and cocoa roasting. It becomes a company's intellectual property. It is proprietary because, like a formula, they do not want their competition to have their specific process.

Which of the following statement is true regarding oil in water emulsions?

Water is the continuous phase.

Emulsifier

a compound or particle that has a hydrophilic part and a hydrophobic part that will bond with both phases in an emulsion, keeping the two phases from separating.

Base

a compound that accepts H+ from the surrounding medium.

Acid-

a compound that donates a H+ to the surrounding medium.

Buffer-

a compound that donates and/or accepts H+ from the surrounding medium on an asneeded basis to maintain a steady pH of the system.

Leavening acid

a group of organic and inorganic acids which form a component of chemical leavening systems. Chemical leaveners are used to provide volume and characteristic crumb structure in batter cakes and other sweet baked goods. · Organic acids: tartaric, fumaric, cream of tartar, glucono delta lactone · Inorganic acids: SAPP, SALP, MCP, SAS, DMP

water of hydration

a layer of water surrounding a hydrophilic molecule.

Solution

a mixture of solute and solvent where the solute has a particle size of less than 1 nm in diameter. The solute, such as sugar or salt, completely dissolve down to the molecular or ionic level in the solvent, such as water. A granule of sugar will completely dissolve down to the individual sugar molecules that now become surrounded by the water.

Refractometer

a scientific instrument that measures total soluble solids. It is an instrument used in the fruit and fruit juice industry to measure sugar content.

Hydrocolloid

a water-soluble colloid. Examples include vegetables gums, gelatinized starch, egg and milk proteins.

What are the two polymers (fractions) that make up starch?

a. Amylose b. Amylopectin

Applications of starches used in the food industry.

a. Beverages b. Confectionary c. Processed Foods d. Bakery Products e. Desserts f. Dairy Products

You are making a fruit sauce and want to stick with a native starch. Choose a starch that you believe is best suited for the fruit sauce and clearly describe why.

a. Choose a root starch such as Arrowroot - is has a higher amylopectin content than the cereal starches and it therefore more stable to acid.

Why are native starches not ideal for use in packaged foods - give four examples where a modified food starch would work better. Be sure to indicate why.

a. Native starches are fragile and do not hold up to high shear, high heat, freezing, or acid conditions. b. Modified food starches are stabilized and will hold up under stress conditions such as those listed above. Examples include processed foods such as canned soups, sauces, and pie filling - foods that are retorted using high heat and pressure. They are used in frozen foods to prevent retrogradation and improve freeze-thaw stability. They are used in processing of foods that need high shear. They can be used in fruit sauces where the high acid content to hydrolyze a native starch.

1) What are the two sources of starches?

a. Root b. Cereal

1. Explain the difference between soluble and insoluble dietary fiber:

a. Soluble dietary fiber can be hydrated by water. b. Insoluble dietary fiber is packed too tightly for water to get in and hydrate the molecules making up the fibrous bundles. c. Neither can be digested by humans - we do not have the digestive enzymes to break down dietary fibers into their monomer units. Nothing can be absorbed through the gut and into the bloodstream larger than a monomer, with respect to carbohydrates and proteins.

1) List three reasons starch is used in formulating food products.

a. Starch is used in formulating food products for many reasons. It is used to: i. Thicken ii. Gel iii. Bind iv. Dust v. Glaze vi. For adhesion vii. Stabilization viii. Emulsify ix. As a Fat Replacer x. Texture xi. Mouthfeel xii. To add freshness

Which type of native starch is usually used to make Modified Food Starches?

a. Waxy Maize (a high amylopectin starch)

1. Describe Starch Gelatinization:

a. When beginning to thicken a sauce with starch, you first need to add the starch to cold water (slurry) or fat/oil (roux) and mix well. i. You want to separate each granule from the other because when heat is applied, and the protein coating of the granules begins to get sticky with hydrogen bonds, the granules will stick to each other, rather than allow water to flow into the granule, which is what you want in order to get maximum thickening. b. When you are ready to apply heat and begin the gelatinization process: i. Starch granules, in the presence of water and heat, will begin to absorb water through the tough protein coat. This makes the starch granules swell and thickening begins. As the process continues and more heat is applied, some of the granules will pop open and spill some of the amylose out into the medium. Thickening is at its maximum when the granules are at their maximum swelling, and some of the granules have spilled some of their amylose out. Thinning can occur if the heating continues and the granules begin to implode. The sauce will lose its thickening power from the swollen granules but will keep the thickening due to the starch fractions that have spilled out.

Describe Retrogradation.

a. a process which occurs when starch chains start to re-associate into an ordered structure. The amylose and amylopectin chains in gelatinized starch realign themselves, causing the liquid to gel, also known as Syneresis or Weeping. -occurs under cold conditions.

List the seven functions of food acids discussed in lecture and give examples of how acids can be used in each application

a. pH Control - Food acids control pH because they are weak acids that act to buffer food systems. Choosing the correct acid to buffer foods to a particular pH is key. For example, when making cheese you need to separate the curd from the whey - to do this you need to reach a pH of between 3.3 and 3.5. Milk has a pH of around 6.8, vinegar has a pH of around 2.2, adding a small amount of vinegar to milk will cause the two buffer systems to compete and the pH will be lowered to the pH that will cause the casein proteins to precipitate out of solution. If you use just any acid, it may not bring the pH to the desired level to achieve the separation of curds and whey. b. Preservative - Food acids act to preserve foods by lowering the pH below the pH of 4.6; this is in line with preventing C. botulinum from creating the deadly botulism toxin. c. Leavening agent - Food acids act as leaving agents as they are used in baking powders to release hydrogen ions at specific times/temperatures. The hydrogen ions then react with baking soda, which is part of the baking powder system, creating CO2 gas and water, leaving behind the sodium ion. The food acids used will have a solubility in line with the correct timing/temperature for release. In other words, WHEN the hydrogen ions dissociate from the leavening acid is key to WHEN the reaction takes place. Fast acting baking powders will have leavening acids with low temp solubility and double acting baking powders will have leaving acids with both low temp solubility acids and higher temp solubility acids. In some case the same acid will release some of the hydrogen ions at one temp and then at a higher temp release more. This is how you can have a double acting baking powder with just one leavening acid. d. Chelating agent: Anti-oxidant synergists - molecules (in this case food acids, which we are learning in this lecture) that bind up metals to prevent them from interfering with antioxidant activity in a food system. e. Buffering agent - a molecule that gives off or accepts hydrogen ions from the surrounding medium in an effort to maintain a steady pH in the system. f. Flavoring agent - flavor is highly influenced by taste. The acid imparts a particular taste to foods/beverages that will enhance the aroma of the system. Food acids give balance to the overall flavor of a food/beverage system. g. Gelling/Coagulating Agent - in foods, acids are used to buffer a system to a specific pH where a particular gelling agent will behave in the manner the product developer desires. For example, sodium alginate forms a gel in the presence of calcium ions when enough carboxylic acid groups are dissociated (lost their hydrogen ion) therefore have a negative charge - this works when the two alginates are pulled (glued) together by the divalent cation calcium.

Total Acidity

also called Titratable Acidity, is the total amount of all the available Hydrogen ions in a solution, i.e. ions that are both free in solution (as H+) and those that are bound to undissociated acids and anions

divalent cation

an cation with valence of 2+. This type of ion may form two chemical bonds with anions.

Intermolecular bonding-

forces which mediate interaction between molecules, including forces of attraction or repulsion which act between atoms and other types of neighboring particles, ex. atoms or ions.

Polysaccharide

higher saccharides with many sugar units. Usually between 10 and 2 million sugar units all linked together with chemical bonds.

a. Define a suspension: b. Give examples of food systems that are classified as suspensions

i. A suspension is a coarse dispersion where the particle size (the dispersed phase) is greater than 100 nm in diameter). Examples are an uncooked starch and water mixture (slurry), peanut butter, orange pulp in orange juice, fine particles in a salad dressing.

Emulsion:

one of the four types of colloidal dispersions. An emulsion is liquid particles dispersed, but not dissolved, as droplets in another liquid or solid. Dispersed but not dissolved because they involved who immiscible phases such as oil and water. Examples include Mayonnaise, cake batter, heavy cream, milk chocolate.

Chelating agent

or sequestering, agents protect food products from many enzymatic reactions that promote deterioration during processing and storage. These agents bind to many of the minerals that are present in food (e.g., calcium and magnesium) and are required as cofactors for the activity of certain enzymes

Colloid

particles are between 10-100 nm in diameter and do not precipitate out of solution.

Food Acid

substances that release hydrogen ions and a salt part in a water solution; they dissociate. Food acids are the only edible acids. The sharpness in the taste of any food is due to the presence of these acids. All fruits have these acids in some quantity and the result is that typical taste.

Hydrolysis

the breakdown of higher polymers into their monomeric units with he addition of water.

Dispersed phase

the particulate that is dissolved or suspended.

Continuous phase

the phase that is the solvent (ex. Water, or oil in a water-in-oil emulsion).

1) Describe Pasting.

the phenomenon following gelatinization, which involves further granular swelling, additional leaching of amylose from the granule; and eventually the total disruption of the granules, resulting in the formation of starch paste.

Oligomerization:

the process of converting a monomer or a mixture of monomers into an oligomer.

Rheology

the study of flow and deformation characteristics of foods . The force could be squeezing, pressing, pulling, cutting, biting or even pouring the material. When a liquid is poured, for example, the force applied is gravity . In food science, rheology is especially relevant to the perception of mouthfeel and texture. Examples of rheological terms: viscosity, pseudoplastic flow, elastic (a solid that holds it shape when a force is applied), plastic (a soft, moldable solid that deforms when a force is applied; e.g., AP shortening), brittle (a hard solid that shatters into shards when a force is applied; e.g., peanut brittle, cooked egg white, kappa carrageenan gel).

Solvation Sphere-

water immobilized by ions. Fully charged ions (such as Na+ and Cl-) attract water molecules at the partially positive sites on the water molecule. The partially positive hydrogens on the water molecule orient themselves in a spherical position around the negative charged Cl- and the partially negative charges on the oxygen do the same around the positively charged Na+. This solvation sphere is usually around two layers of water deep. This is why salts can bind up so much water. The immobilize it by this electrostatic attraction between the fully charged ions and the partial charges on the water molecules. Remember, water is not multitasking, so if it's immobilized in solvation spheres, then it cannot participate in any other chemical or biological reaction, including microbial degradation. Bound water helps preserve food.

Bound Water-

water that is unavailable to participate in any other physical, chemical, biological, or microbial reaction. It is bound to either a molecule or an ion in a food system. Bound water becomes part of the molecule it is bound to and is no longer free to boil at 212F or freeze at 32F. It no longer behaves as free water.

Give examples of food systems that are classified as suspensions:

§ Peanut butter § Tiny crystals of sugar in chocolate fudge § Starch slurry (before cooking)