L4 Sound & Texture

What are the three phases of visual pattern recognition?

• data: exposure to data

• pattern recognition: exposure to accumulation of data becomes a pattern

• annotation: ability to interpret, make decisions (do we like it? do we not like it?) and act based on complex data synthesis

Besides vision do other senses prompt our brain to recognize patterns?

yes

• acoustic sound: we commit learning the lyrics etc and pay to listen to it

What is so significant in regard to pattern recognition in humans and animals?

not only do we develop an annotation, we also tend to develop a preference for and against particular sensations that is dependent on pattern recognition

What does the concept of preference illuminate?

fundamental biological selective pressure that can be placed in a food perspective

• negative = run away

• positive = run towards

How is touch on the basis of our skin perceived?

have specific cells that transduce heat, cold pain, and pressure into electo-stimulation and nerve impulses destined to separate parts of brain

What are pacinian corpuscles?

pressure cells found on skin and tongue

• responsible for pressure sensation

• works similar in transduction compared to hair cells

• greater pressure produces greater frequency of nerve impulses

• large = 1mm in size and are mms apart

What are merkel cells?

pressure sensing cells on the papillae of our tongue

• capable of assessing the pressure and texture of food

Does the size of the particles on our tongue matter in regard to whether or not we perceive them?

No because we can detect things on both the macro and microscopic (micrometer) scale

• have remarkable tactile acuity/sharpness when it comes to detecting textures

Who is Lina Engelen? Describe the experiment she ran.

PhD student at the Amsterdam school of Dentistry that had her thesis on how people were able to perceive the texture of foods at such a scale (so small) when we did not have the instrumentation to actually measure it

• experiment:

  • suspension of particles of known sizes were placed on the tongues of volunteers and they were able to tell the difference quite well

  • anesthetized muscles in the tongue

    • were able to perceive the pressure but were not able to move their tongue, and as a result they could not tell texture at all

  • conclusion: the accuracy and sensitivity to texture measurement requires tongue movement and pattern recognition that our brain can understand

The structure of food is critical for what three things?

1) quality

2) safety

3) sensory preferences

Who is Allen Taylor? What did he study? Importance?

Who?

• Professor at Tufts University who studied nutrition

Studied?

• tried to understand the macular (tissue in the back of your eye that supports all the optical properties of it) and it’s degeneration and how to protect it during aging

• developed antioxidant cocktails and nutrients to try and slow the process of macular degeneration

• used the glycemic index (independent variable) to develop food structure and related it to odds of developing macular degeneration (dependent variable) and did this for a population (multiple regression epidemiology)

Importance:

• gave the antioxidant cocktail and those with slow glycemic index had lower odds of macular degeneration whereas those with a fast glycemic index had higher odds of macular degeneration

  • all in all diet is not just about essential nutrients it is also about the structure of foods because that impacts the nourishment of foods.

What is the glycemic index?

an indicator of the ability of different types of foods that contain carbohydrates to raise the blood glucose levels within 2 hours

• typically foods that have carbs that break the quickest during digest have the highest glycemic index

What is multiple regression epidemiology?

relating one variable (independent) to another (dependent) according to mathematical (statistical) probabilities

• no statistical relationship = straight line

• negative correlation/relationship = inverse relationship between both variables

• positive correlation/relationship = proportional relationship between both variables

What does it mean when a glycemic index is high?

glucose enters the blood quickly

What is the native structure of commodities?

the native structure of commodities

• the three-dimensional networks supporting natural tissues in plants and animals

• indifference to food structure can be seen through the term “whole grain”

What is the induced structure of processing?

• the three-dimensional networks induced explicitly during processing of commodities

  • ex: yogurt is acid-induced gelation of milk caseins

What is the assembled structures of cuisines?

• the three-dimensional networks provided by specific ingredients

  • ex: cake is a heat-induced gelled emulsion stabilized by a wheat protein network and it’s structure provides a desirable texture

• culinary professionals have been trying to perfect structure in this way

Overall why is food structure important?

it is a sense-able key to the quality of food

Describe the food structure of bread.

• heat fixed gluten protein dough

• gluten and starch based structure

• air provides shortening of protein fibers

Describe the food structure of cheese.

• enzyme induced gelation of milk caseins

• fat plays a role in plasticizing the gel

Describe the food structure of ice cream.

• water and lipids are forming structure

  • lipids in the milk are crystallizing forming lattices of fat that help to stabilize the fixed foam

Describe the food structure of popcorn.

• liquid to gas phase change (water to steam)

  • expands the structure into foam which is stabilized by a network of starch and protein

Describe the food structure of chocolate.

• crystals of solid fat in a three dimensional network

Why is water an active folding environment for proteins?

• parts of the protein that natively have to be on the outside like water

• parts of the protein that natively have to be on the inside don’t like water and this drives it into it’s structure

Besides water, what is another folding environment for proteins?

biomembranes

What is AlphaFold?

computational system from Google’s Deep Mind AI that can show the three-dimensional model of a folded native protein

• doesn’t know what would happen to food proteins when they are unfolded