extension.usu.edu food myths fact or fiction? karin allen, phd usu extension food quality &...

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Food MythsFact or Fiction?

Karin Allen, PhDUSU Extension Food Quality & Entrepreneurship

FCS Videocast SeriesSeptember 24, 2013

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Fact or Fiction?

Alcohol evaporates out of foods during cooking.

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Fiction!

Alcohol evaporates out of foods during cooking.

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Ethanol or Ethyl Alcohol

• Hydrophobic and hydrophillic regions

• Stabilizes flavors and aromas

• Boiling point 170°F

Extract Flavor McCormick Watkins Massey

Vanilla Pure 41%Imit. 26% Pure 35% Pure 35%

Almond Pure 32%Imit. 32%

Pure 40%Imit. 45% Pure 90%

Orange Pure 79% Pure 89% Pure 90%

Peppermint Pure 89% Pure 91% Pure 83%

• Liqueurs (orange, berry, mint, etc.): typically 15-30%

• Wine (red, white, blush): 10-15%

• Liquor (rum, whiskey, vodka): 35-50%

Hydrogen Bonding in Ethanol

Hydrogen Bonding between Ethanol and Water

USDA Nutrient Retention Factors

Cooking Method Time % Alcohol Remaining

Flambée n/a 75%

Baked/simmered 15 min 40%

Baked/simmered 30 min 35%

Baked/simmered 1 hr 25%

Baked/simmered 1.5 hr 20%

Baked/simmered 2 hr 10%

Baked/simmered 2.5 hr 5%

Source: USDA Table of Nutrient Retention Factors, Release 6 (Dec. 2007)

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Fact or Fiction?

Freshly ground wheat shouldn’t be used for bread.

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Fact!

Freshly ground wheat shouldn’t be used for bread.

Gluten

Glutenins Gliadins

Gluten Formation

Gluten Requires Disulfide Bonding

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Fact!

Freshly ground wheat shouldn’t be used for bread.

Changes During Maturing

• Glutathione content decreases naturally after milling

• Chemical processing speeds this up

Why is Glutathione Bad?

Why is Glutathione Bad?

Glutathione

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Recommended Aging Time is 10 Days

• Research shows glutathione decreases by up to 43% after 10 days for some wheat types

• Bread volume increases roughly 10% using 10-day old flour

• Results between 10 and 40-day old flour are very similar

Source: Chen X. and Schofield J. D. (1996). “Changes in the Glutathione Content and Breadmaking Performance of White Wheat Flour During Short-Term Storage”. Cereal Chemistry 73(1):1-4.

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Fact or Fiction?

Freshly-squeezed is more nutritious than juice made from frozen concentrate.

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Fiction!

Freshly-squeezed is more nutritious than juice made from frozen concentrate.

Which apple would you choose?

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Blemished Foods in Food Processing

• The Food and Agriculture Organization reports post-harvest losses account for over 20% of total food waste world wide

• Fruits and vegetables used in processing must still meet USDA quality standards• Only 5% of apples for processing can have

worm holes

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But aren’t nutrients lost in processing?

• Frozen juice concentrates are no longer heated to evaporate water (they are still pasteurized for safety reasons)

• Water can be removed by freezing or membrane filtration

Freeze Concentration

Membrane Filtration

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But aren’t nutrients lost in processing?

• Frozen juice concentrates are no longer heated to evaporate water (they are still pasteurized for safety reasons)

• Water can be removed by freezing or membrane filtration

• Both techniques preserve sensitive nutrients such as Vitamin C

USDA Table of Nutrient Retention Factors, Release 6 (Dec. 2007)

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Fact or Fiction?

Red kidney beans should be boiled first, not added

dry to a slow-cooker.

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Fact!

Red kidney beans should be boiled first, not added

dry to a slow-cooker.

Phytohaemagglutinin

Levels of Protein Structure

PHA Activity in kidney beans

Variety Soak time

Cook conditions

Activity units before

Activity units after

Red kidney 18 hrs -- 53000 18000

Red kidney 18 hrs 100°C, 10 min 18000 6800

Red kidney 18 hrs 100°C, 20 min 18000 1300

White kidney 18 hrs -- 44000 28000

White kidney 18 hrs 100°C, 10 min 28000 0

White kidney 18 hrs 100°C, 20 min 28000 0

Red kidney 18 hrs 70°C, 20 min 28000 35000

Red kidney 18 hrs 80°C, 20 min 28000 215000

Adapted from Bender A.E. (1983). “Haemagglutinins (Lectins) in Beans”. Food Chemistry 11:309-320.

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FDA Recommendations

• Soak in water for at least 5 hours.

• Pour away the water.

• Boil briskly in fresh water, with occasional stirring, for at least 10 minutes.

Undercooked beans may be more toxic than raw beans!

Source: FDA Bad Bug Book 2nd Edition (2012)

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Fact or Fiction?

Pre-packaged roasts are safe even if cooked rare.

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It Depends…

Pre-packaged roasts are safe even if cooked rare.

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USDA Safe Cook Temps

ProductMinimum Internal

Temperature

Beef, Pork, Veal & Lamb

Steaks, chops, roasts 145°F

Ground 160°F

Poultry

Breasts, legs, thighs, wings 165°F

Ground 165°F

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Why is there a lower temperature for red meats?

• Intact muscles are sterile (bacteria cannot penetrate into the muscle)

• Meats become contaminated during harvest and processing

• Any cut surface can contain bacteria• Ground meats, cube steaks

• What about roasts?

Depends!!!Was it Injected or Tenderized?

So which pre-packaged meats are?

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How can I tell?

• As of June 2013, USDA requires all mechanically tenderized or injected meats to be labeled

• Must give cooking instructions, including a validated safe minimum internal temperature

• Consumers should follow similar recommendations when injecting roasts at home

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Questions or Comments?

Thank You!