Lesson 3 Flashcards
fat and sugar substitutes (sweeteners), sensory perceptions of foods
3 types of fat substitutes
- protein-based
- carbohydrate-based
- fat-based
Why use fat substitutes?
- consumers are demanding healthier foods with less fat and calories
- increase in health problems (e.g. overeating, obesity, sedentary lifestyle)
Simplesse
protein-based fat substitute
soy, milk (whey), or egg white protein is partially coagulated by heat, creating a micro-dispersion (microparticulation) consisting very small spheres of protein and water (0.1-0.2 microns)
- dispersion perceived as fluid with creaminess and richness of fat
- tiny particles are below the size limit we can feel with our tongue
Where is Simplesse used?
ice cream, yogurt, cheese spread, salad dressings, margarine, mayonaise, coffee creamer, soups and sauces
not baked goods and chips; coagulation by heat forms microgels and the structure of gels collapses when heated
Maltrin
carbohydrate-based fat substitute
- derived from corn, potato, wheat, tapioca, which contain cellulose, starch, gums, maltodextrins and fibre
- smooth mouthfeel and bland flavor
- fully digestible (4 Cal/g with fat = 9 Cal/g)
other carb-based fat substitutes available range from non-digestible to partially digestible (0-2 Cal/g) like Avicel and Betatrim
Where is Maltrin used?
margarine, salad dressings, frozen desserts, frostings, processed meats
like Simplesse, doesn’t withold integrity at high temperatures
Olean
fat-based fat substitute
- a sucrose polyester, also known as olestra
- approved in the US in 1996 but not in Canada
- can withstand high temperatures (e.g. frying)
- mimics rich taste and creamy texture of ordinary fat (because it’s made primarily from fat!)
Olestra as a sucrose polyester
made of 6-8 fatty acid chains attached to a sucrose molecule instead of 3 FA chains attached to glycerol
Consequences of large portions of Olestra snacks
abdominal cramping or changes in stool consistency
similar to consumption of high-fiber diets
Why does Olestra cause digestive problems?
not absorbed or digested, rather it accumulates in the gastrointestinal tract
- fat-soluble nutrients in olestra-containing foods or other foods consumed at the same time are also not absorbed
- FDA required the addition of vitamins A, D, E, and K to compensate but the warning requirement was lifted in 2003
Sweetener
according to food and drug regulation (FDR)
a food additive used to impart a sweet taste to food
e.g. aspartame, maltitol, sorbitol
Sweetening agent
according to FDR
any food for which a standard is provided in Division 18, excluding those listed in tables to Division 16
e.g. white and brown table sugar, molasses, and honey
3 reasons we use sweeteners
or sugar substitutes
- for those with diabetes
- for individuals concerned with high caloric intake
- to reduce the risk of tooth decay (or cavities)
Characteristics of sweeteners
- non-caloric: contain 0 Cal/g and not metabolized by the body (e.g. Acesulfame potassium, sucralose)
- non-nutritive or low-calorie: contribute ≤ 4 Cal/g but trace amount used due to high sweetness (e.g. Aspartame)
Acesulfame Potassium (K)
non-caloric sweetener
- 200x sweeter than sucrose
- heat-stable
- no contribution to cavities
- not metabolized by the body (0 Cal/g)
- ADI of 15 mg/kg of body weight
discovered in 1967, marketed as Sunett, Swetone
Sucralose or Splenda
non-caloric sweetener
- a chlorinated molecule: 3 hydroxyl groups (OH) of the sucralose molecule are replaced by chlorine
- 600x sweeter than sucrose
- heat-stable
- not metabolized by the human body (though questionable)
- ADI of 9 mg/kg body weight per day
- no effect in carbohydrate metabolism (no increase in blood glucose or insulin levels)
Aspartame
low-calorie sweetener
- 2 amino acids: phenylalanine and aspartic acid
- 180-220x sweeter than sucrose
- 4 Cal/g
- ADI of 40 mg/kg body weight per day
discovered by accident in 1965 (Schlatter)
Disadvantages of Aspartame
- phenylketonuria (PKU)
- degrades at high temperatures and over time, resulting in byproduct DKP, so cannot be used on baked goods
best before date necessary on products
Neotame
low-calorie sweetener
- 2 amino acids: phenylalanine and aspartic acid
- 7000x sweeter than sucrose
- 4 Cal/g
- no increase in blood glucose or insulin levels
- ADI of 2 mg/kg body weight per day
- relatively heat-stable
- no problem for people with PKU
newer version of aspartame
Sugar alcohols
low-calorie sweeteners
- naturally in many fruits but less sweet than sucrose (typically used along with other sweeteners)
- cooling sensation from alcohol
- do not promote dental caries
- no major increase in blood glucose or insulin levels
- slow absorption in body so may cause laxative effect (threshold 20-40 g/day)
- partially digested (1.5-3 Cal/g)
e.g. sorbitol, mannitol, xylitol
Table-top sweeteners
allowed in Canada
- aspartame, acesulfame-K, sucralose (also permitted as sweeteners in foods)
- cyclamate, saccharin
saccharin is the oldest sweetener
* allowed only in pharmaceuticals
* banned in 1970 but reinstated in 2014
2 kinds of sensory testing
- analytical (objective) or product-oriented
- affective (subjective) or people-oriented
Analytical sensory testing
- quality/quantity of a characteristic
- similarities/differences between products
- standardization
- fewer people, selected and trained
2 kinds of tests used in analytical sensory testing
- discriminative (differences between 2 products)
- descriptive
Affective sensory testing
- acceptance/preference of a product
- first impression and personal reaction
- large number of panelists, representative of population
3 kinds of tests used in affective sensory testing
- hedonic (liking)
- acceptability (whether a product meets basic expectations or standards)
- preference
3 aspects of food quality detectable by our senses
- appearance factors
- textural factors
- flavor factors
Examples of appearance factors
food quality
color, shape, size, gloss, consistency, presence of defects
Non-biased testing for flavor
food quality
blindfolds or sensory testing facilities with special lighting (red light)
4 methods for testing texture
food quality
- cutting
- compression
- tensile strength (tearing and pulling apart)
- shearing (pressing and sliding)
Taste component of flavor
- water-soluble substances
- interact with sensory receptors on the tongue
- detected in the mouth-tongue
Smell component of flavor
- fat-soluble and volatile aroma compounds
- interact with receptors in the nose (olfactory region)
e.g. food seems bland when you have a cold because your nose is plugged so only water-soluble compounds are detected
How can you test for the flavor of food when you have a cold?
- flavor test: taste food with/without aroma
- taste test: compare sweetness of sugar near the tip vs sides of tongue; note tongue location that senses bitterness of coffee or beer
4 basic taste sensations
and proposed 5th sensation
- sweet, salty, sour, bitter
- umami
receptors are the same all over the tongue but are located in papilae that filter out different ions
What provides sweet taste?
- mono and disaccharides
- some amino acids and peptides (e.g. aspartame)
- synthetic sweeteners (e.g. saccharin, cyclamate)
- others (e.g. chloroform, lead acetate)
What provides salty taste?
true salty taste only comes from sodium chloride
no successful substitutes!
* K-chloride gives a salty and bitter taste
* Na-sulphate gives a bitter and slightly salty taste
* Ca-chloride is very bitter
* Cesium chloride is sweet
What provides sour taste?
protonated H+, organic and inorganic acids
e.g. vinegar (acetic acid), others (citric, tartaric, malic, lactic, fumaric, phosphoric acids)
What provides bitter taste?
- typically alkaloids (e.g. caffeine in coffee and tea, or theobromine in chocolate)
- some salts (e.g. Na-sulphate, Ca-chloride)
- amino acids and peptides (e.g. sharpness, bitterness of aged Cheddar cheese)
Umami (savory)
- discovered in 1908 by Professor K. Ikeda while working with Kombu seaweed
- extracted cyrstals of glutamic acid, converted to glutamate (found in MSG), which creates a distinctive taste
e.g. high glutamate content in soy sauce, parmesan cheese, roquefort cheese
Flavor enhancers
i.e. potentiators, modifiers
modify or enhance the intensity or quality of taste of another substance
- MSG (meaty and vegetable flavors), 5’-nucleotides (meaty flavors)
- torula yeast, autolyzed yeast extract, hydrolyzed protein, yeast extract naturally have concentrated MSG
- maltol modifies flavors of high carbohydrate foods and beverages
- miracle fruit gives a sweet aftertaste
Astringency
- a physical sensation desribed as a puckering in the mouth
- attributed to tannins or polyphenols of high molecular weight (e.g. black tea)
Pungency
sensation of spicy heat in the oral cavity
e.g. chili peppers
Coolness
various sugar alcohols such as xylitol and sorbitol, or compounds such as menthol (e.g. chewing gum)
