Food Science

Acesulfame Potassium

(130x sweeter) stable in high temps

Advantame

(20,000x sweeter) More stable than aspartame. Only available to commercial and food ingredient markets. Approved as sweetener and at ulta-low levels as a flavor enhancer.

Saccharin

(200-700x sweeter than sucrose) - Stable under extreme processing conditions -Bitter after high concentrations -Not been found to find cause cancer.

Aspartame

(200x sweeter) taste almost identical to sucrose, not heat stable

Stevia

(300x sweeter) Stable in high temps in acids

Monk Fruit

(300x sweeter) cost twice as much as stevia. Been used in China for 800 years

Sucralose

(600x sweeter) cannot be digested. Cannot be digested, remains stable in processing, soluble in water, easily added to foods.

Neotame

(7,000-13,000x sweeter) Stable in high heat and is approved for baking applications. Flavor enhancer when used in low levels. Safe for people with PKU unlike aspartame.

How do enzyme inhibitors prevent enzyme action?

- They prevent enzyme-substrate complex from forming. They can change the shape of the enzyme of the substrate. Prevent bacteria and mold by stopping digestive enzyme from working. Naturally occur in foods.

Carotenoid family (carotenes)

-Alpha-carotene: carrots and pumpkins -Beta-carotene: dark green leafy vegetables -Beta-cryptoxanthin: papayas, oranges and tangerines -Lycopene: tomatoes, watermelon, guava, and red peppers Heat stable, so greater concentrations in cooked

How to maintain maximum phytochemical levels in food items

-Photochemical peak at full ripeness -Rapid freezing at point of harvest maximized photochemical and protects food until consumed.

What are bulking agents?

-They combine with alternative sweeteners to enhances the texture or thicken the consistency of food products. -Polydextrose is a bulking agent that mimics the mouthfeel of sugar and is used in reduced-calorie products.

How to preserve vitamins and minerals at home during food storage and preparation

1) Rince instead of soaking 2) Keep food in large pieces to reduce surface area to light, air, and water 3)Cut up fruits and vegetables just before cooking/serving 4)Choose stainless teel, glass, and aluminum cookware for foods that are easily oxidized 5)avoid adding acids or alkalis to vegetables 6)Steaming over boiling

Organosulfur compounds

2 subgroups: (Sulfur-containing phytochemicals Allyl sulfides Glucosinolates - Isothiocyanates -Indoles

What are minerals?

A solid inorganic substance of natural occurrence. Important for making enzymes and hormones

What is fortification?

Adding nutrients to food to correct a nutritional deficiency

What are the 5 photochemicals?

Alkaloids Organosulfur compounds polyphenois phytosterols

flavors and phytochemicals in food processing

Allyl sulfides unstable when chopped and cooked, flavors become milder -Isothiocyanates unstable in heat causing flavors to become stronger. -Polyphenol's astringency decreases when ilk is added. -Tannins cloud liquids by binding with proteins cause sediment to develop and settle.

Alkaloids

Bitter heterocyclic compounds with nitrogen in the carbon rings Sources: 1)Solanine: potatoes 2)Capsaicin: peppers 3)Alpha-tomatidine: green tomatoes 4)Caffeine: Coffee, tea, chocolate and soft drinks 5)Quinine: Tonic water

What is the function of lipases in food production?

Break apart lipids. Improves texture of many products including cheese, ice-cream, margarine, butter and many baked goods. Extracts unwanted egg yolk from egg white to improve whipping properties

What is the function of proteases in food production?

Break apart proteins. Tenderize meat, breaking long protein fibers, reduce size of proteins extracted from malt and grains, reduce mixing time, increase pliability of dough, change food into different product such as milk into cheese.

What is the function of carbohydrases in food production?

Breaks down starches and sugars. Makes corn syrup and high-fructose corn syrup, ferments wine and beers, stabilizes chocolate syrup, clarifies fruit juices and vegetable canning liquid, salvages and reuses scraps of candy from manufacturing

Phenolic Acids

Ellagic acid: Grapes, cranberries, strawberries, raspberries, citrus, tomatoes, carrots, whole grains, and nuts Phenylindanes: Found in coffee (bitter taste)

How are enzymes named?

End in -ase

Why does enzymatic browning occur and how can you prevent it?

Enzymes called oxidases react in the presence of oxygen and cause darkening or browning. This is prevented through storing in an oxygen-free environment and through using acids as an enzyme inhibitor.

Flavonoids

Flavor compounds in foods. Red and white color pigments that are seen in food Over 6000 have been identified Families include anthocyanins, flavanols, isoflavones, flavanols

Terpenes

Flavors found in citrus and many seasonings and herbs. 3 subgroups of compounds: -Terpenoids -Carotenoids -Saponins Terpenoids: Common terpenoid is the taxol which is extracted from the pacific yew tree and used in treating of ovarian cancer.

Flavanols (flavonoid family)

Goup of compounds known as catechins and the Epillocatchin gallate (EGCG) is the most researched Sources: tea, berries, peaches, plums, and avocado

How does temperature effect enzyme activity?

Heat increases enzyme activity

Carotenoid family: Xanthophylls

Lutein: Kale, spinach, corn, bell peppers, parsley, pistachios Zeanthin: Dark leafy greens, peas, summer squash, pumpkin, brussels sprouts, broccoli, asparagus, lettuce, carrots, and pistachios Astaxanthin: Algae, yeast, salmon, trout, krill, shrimp, and crayfish

How does substrate concentration effect enzyme activity?

More substrate = greater reaction up to saturation point

What are food analogs

Natural or manufactured substances used in place of traditional food products or ingredients Ex: Low calorie icecream or non-dairy icecream

How does water effect enzyme activity?

Needs water to react. Lack of water slows or stop enzymatic activity. Water acts as reactant and solvent. Water must be a reactant in the breakdown of macronutrients.

What are phytochemicals?

Non-nutritive substances found in vegetables that appear to have a positive effect on health

What are vitamins?

Organic compounds needed in small amounts to regulate body processes. Enzyme reactions slowed or stopped and body processes impaired if vitamins are missing Fat soluble: A, D, E, and K Water soluble: B and C vitamins

Photochemicals in food processing Color

Phytochemicals preserved when: 1)Color is stable 2)In moist heat -Adding acid to orange colored vegetables changes the color to yellow and creates isomers (same formula, different shape) - Dehydration causes color loss and inability of carotenes to form Vitamin A. -Flavonoids maintain color when cooked with acid, but form salts when exposed to iron or tin.

Flavonoid Family (Isoflavones)

Phytoestrogens or plant hormones (include genistein and daidzen) Sources: Soy products and legumes, chickpeas, Chinese cabbage, bok choy, licorice, and processed foods with soy.

What is enrichment?

Process of restoring some nutrients removed from refined grain products during process

Flavonols (Flavonoid family)

Quercetin: Represents the most popular compound in the family Sources: Red and yellow onions, red and purple grapes, apples, cranberries, asparagus, teas, oregano, turmeric, most lettuces, and peppers.

Anthocyanins (flavonoid family)

Red, purple, and blue color in fruits and vegetables Stability in food affected by acid, heat, light, pH, and temperature

Allyl sulfides

Sources: Onions, garlic, leeks, and chives Reacts with the enzyme allinase to form allicin which gives cut garlic its pungent order.

Phytosterols

Sterols: Have double bond in one of 6 carbon rings Stanols: Do not have double bond Sources: Unrefined plant oils, nuts, seeds, whole grains, and legumes. Enriched sources: margarines, mayo, vegetable oils, milk, and yogurts.

The relationship between substrates and active sites in enzymatic reactions

Substrate= Substance on which an enzyme acts / the thing being changed. Active site = Changes shape of enzyme to allow reaction to occur, then returns to its original configuration after the reaction. -Enzyme and substrate combine, enzyme-substrate complex unstable and breaks apart, enzyme is now available to act again on another substance.

Polyphenols

The most widely studied of the categories Subgroups: phenolic acids, flavonoids

Terpenes subgroup: Carotenoids

Yellow, orange, and red pigments in fruits and vegetables 40 carbon chain with over 600 identified compounds and 50 as precursors for vitamin A More stable in unsaturated than in saturated lipids. @ families of compounds: - Carotenes -Xanthophylis

What is the enzyme-substrate complex?

binding of the enzyme and the substrate, which then speeds up the chemical reaction by lowering the activation energy

What are proteases?

enzymes that break down proteins

How does pH effect enzyme activity?

pH too high or low will denature enzyme

How do electrolytes effect enzyme activity?

positively or negatively charged ions in solution can prevent enzyme from reacting with substrate. Most common electrolyte in food production is salt.

Polyols

sugar alcohols formed from or converted to sugar; sorbitol, xylitol, and mannitol are present in the body or added to foods

Glucosinolates

sulfur-containing irritants in mustard and horseradish Responsible for pungent smell and strong orders Isothiocyanates: subgroup of glucosinolates Indoles: Subgroup but do not contain sulfer Found in large amounts in broccoli, cabbage, kale, cauliflower, and cruciferous vegetables. They become more available when vegetables are cooked.

What is a substrate?

the substance on which an enzyme acts