SENSORY EVALUATION OF FOOD BY Dr Ghulam Abbas

SENSORY EVALUATION OF FOOD BY Dr. Ghulam Abbas

Human Senses The human SENSORY system is a part of nervous system responsible for processing sensory informations. It consist of sensory receptors, neural pathways and parts of brain for sensory perception. • • • Human senses are; Sight Hearing Touch Smell Taste • Additional senses • Pain, balance, motion and acceleration, direction, temperature difference.

Why we eat? • • Hunger Fuel our bodies Psychological ( emotional) eating Boredom

Food Nutrients • “to nourish” • Chemicals the body needs to function, grow, repair itself and creates energy. • Proteins • Carbohydrates • Fats • Vitamins • Minerals • Water

Influences on our food choices • Culture • Geography • Psychology and emotions • Beliefs and religion • Health concerns • Costs • Social, friends • Advertising, current food trends • Likes and dislikes • Special occasions

We taste with all of our senses. • Our flavor perception (opinion or view) is actually determined by the following; • • Smell Taste Appearance sound

• Texture play a big role in our appreciation of foodstuffs: v just think how unappealing food tastes when it is accidentally served at the wrong temperature (such as food served cold, when it should be hot or vice versa).

'Superadditive' personalities • The human brain actually combines the information from each of our senses according to a number of very specific rules. • So, for example, our brains tend to combine weak signals (such as the combination of a very weak taste with a very faint odour) in a 'superadditive' way that gives rise to a perception of flavour.

Sensory cues • If you get the combination of sensory cues (signal) wrong then the brain will not be impressed and it will give a subadditive response. • That is, a response that is far lower than would have been elicited by either of the sensory triggers had they been presented in isolation. • Example: Combining the taste of strawberry with the 'incongruent‘ (different) smell of a savory (salty and spicy) chicken soup.

Where you grew up matters to your brain! • The combinations (smell and taste) that the brain will put together in a superadditive manner will depend upon where you grew up. • So, for example, those people who have grown up in the UK, experienced the combination of a sweet taste together with the smell of almond in their diet, will tend to integrate the smell of almond and the sweet taste of sugar in a superadditive manner.

Where you grew up matters to your brain! • The brain of someone who has grown up in Japan will not integrate sugar and almond in a superadditive manner (since they will not have come across that particular combination of taste and smell in Japanese cuisine).

Continue…. . Instead, Japanese people show a superadditive response to the smell of almond when it has been paired with a salty taste (since that combination of smell and taste is common in Japanese cuisine, especially in things like pickled sauces).

• Thus, brain science help to explain why it is that what tastes so pleasant to the people from one country can taste so bad to someone who has been brought up in another country.

The stronger sense of eating • Another important rule that psychologists and brain-scientists have discovered about how the human brain combines the signals reaching each of the senses is known as 'sensory dominance'. • That is, our brains use the most accurate of our senses when trying to figure out what is around us, and this 'cognitive short-cut‘ (mental abilities) even applies when we are trying to decide what exactly to eat and/or drink.

Food Perceptions • Our sight is generally very accurate in terms of being able to tell us what something is. • Our perceptions tend to be dominated by what our brains see, rather than by what they smell or taste or feel, etc.

Hearing things • Our perception of food is also determined by the sound it makes as we eat or drink it. • In a study, people's perception of the freshness and crispiness of potato crisps could be changed simply by altering the sounds that people heard when they bit into the chips.

Hearing things • In particular, whenever the high frequency components of the crisp-biting sounds were boosted, people would judge the crisps as being both fresher and crisper. • A microphone was placed by peoples' mouths so the crisp biting sounds were picked up and were fed back to the participants ears through a pair of headphones.

Hearing things • Our brains are continuously monitoring the signals going into our ears, and using them in order to help determine what exactly it is we are eating or drinking and just how much we like it. • We don't often pay much attention to the subtle sounds that we make whenever we eat and drink. • Research also showed that people's perception of the flavour of food can also be influenced by the sounds (or music) that is played in the background environment while they are eating.

Hearing things • For example, in one experiment, people were given two scoops of fruit and egg ice cream, one after the other.

Hearing things They had to rate the relative strength of the fruit flavour versus the egg flavour in each scoop. • It was found that when the people heard the sound of farmyard chickens squawking, then the ice cream tasted much 'eggier. ’

Hearing things • When fruit cutting sounds were played over the loudspeaker system, people really thought that the ice cream had a much more prominent fruit taste.

Hearing things • The incorporation of the multisensory cues in the environment effect our perception of the food and drink. • It help to explain why so many of us have had the experience of buying an ordinary drink on holiday has great taste in company of friends rather than when we get it home suddenly tastes poor.

• What happened? • Well, while on holiday your brain was taking in all those pleasant environmental cues such as the smell of the salty sea air, the warmth of the sun on your skin and the sound of the waves crashing on the beach and none of those environmental cues are present when you try the same food back in your own living room, it no longer tastes as good.

SENSES • Flavor – is the distinctive quality that comes from food’s blend of ü Appearance ü Taste ü Smell, odor ü Feel, texture ü Sound

Taste • Taste-buds: sensory organs located on the tongue- cells lining the surface have pores that are activated with contact. • Only foods dissolved in water can gain entry.

4 distinct tastes 1. sweet 2. bitter 3. salt 4. sour

Sweet and bitter • Pass over taste buds • Chemical reaction occurs • Receptor cells send message to the brain Salty and sour • • Tastant molecules pass over taste buds Receptor cells do not perceive them An electrical charge occurs Signals the brain

Odor • Works with flavor • No smell- no taste • Olfactory- organs related to sense of smell • Temperature changes odor

Odor n. Olfactory nerve: a single nerve that ends in sensory cells in the nasal cavity n. Runs straight to the brain n. Respond to odors in the form of a gas n. Cilia (nose hairs) have oily mucus that helps dissolve the odor-carrying gas so they can activate the sensitive nerve cells.

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