The Science of Food Flashcards
Which part of the digestive system does enzymatic hydrolysis of food occur
Small intestine
Define ‘hunger’
Hunger is the body’s physiological response to satisfy the need for food
Define ‘appetite’
Appetite is the desire for food, even when the body is not necessarily hungry
Define ‘satiety’
Satiety is the state or feeling of fullness after eating, where there is no further need or desire for food
Explain the ‘sensory appreciation of food’
The information humans get from their senses surrounding food and how they interpret that information
Difference between mechanical and chemical digestion
Mechanical digestion is the body’s use of physical force to digest food
e.g. muscular contractions in oesophagus
Chemical digestion is the breakdown of food using chemicals such as enzymes and acids
e.g. salivary amylase released from salivary glands in the mouth to break down CHO into simple sugars
Mechanical digestion in the mouth
Teeth bite off pieces of food and chew into manageable pieces
Swishing action of the tongue helps lubricate the food with saliva
Chemical digestion in the mouth
Salivary glands release saliva containing an enzyme called salivary amylase to break down CHO into simple sugars
Salivary glands release saliva and helps lubricate the food to form a bolus
Mechanical digestion in the stomach
Muscular walls of the stomach contract with physical force to churn and break down the bolus into a liquified mass called chyme
Muscular walls of the stomach contract and squeeze the chyme towards the small intestine
Chemical digestion in the stomach
Stomach juices containing hydrochloric acid and the enzyme pepsin break down protein into amino acids
Acid in the stomach activates lingual lipase and gastric lipase to begin the breakdown of fats into fatty acids
Mechanical digestion in the small intestine
Villi that lines the walls of the small intestine absorbs macronutrients
Chemical digestion in the small intestine
The enzyme pancreatic amylase breaks down CHO into glucose
Protease splits proteins into amino acids
Bile and pancreatic lipase further breaks down fats into fatty acid and glycerol
Define ‘enzymatic hydrolysis’
A chemical digestive process that break down food, for example, salivary glands in the mouth release saliva containing an enzyme called salivary amylase to break down CHO into simple sugars
What are the 4 different types of fibre
Resistant starch e.g. chickpeas
Soluble fibre e.g. oats
Insoluble fibre e.g. whole grain breads
Readily fermentable fibre e.g. leeks
Role of fibre for satiety
Fibre is an indigestible carbohydrate found in plant foods that provides satiety, assisting with bowel movement and contributes to good health
Role of fibre for gut health
High fibre diets provide prebiotics that feed good bacteria in the gut. Variety of good bacteria promotes digestion and overall health
Foods with a positive impact on health
Whole foods that are high in fibre e.g. whole grains and vegetables
Prebiotics e.g. apples and onions
Probiotics e.g. yoghurt and kimchi
Foods with a negative impact on health
Highly processed foods e.g. salami and chips
Discretionary foods e.g. milk chocolate and lollies
Inflammatory foods e.g. fried food and soft drinks
Difference between prebiotics and probiotics
Prebiotics come from carbohydrates and feed good bacteria by stimulating growth and activity of naturally occurring colonic bacteria e.g. onions and apples
Probiotics are live bacteria that make it a less inviting place for bad bacteria to survive, while also enhancing the good bacteria present in the stomach e.g. yoghurt and kimchi
Why the Australian Dietary Guidelines and the Australian Guide to Healthy Eating are credible (3 principles of research)
1) Recognition of credible sources
2) Evidence-based information
3) Accurate analysis of data
Recognition of credible sources
The ADGs are a credible source because the NHMRC consulted with credible sources including:
1) Food, nutrition and health experts across Australia and around the world
2) Government health departments
Evidence-based information
The review of the ADGs are underpinned by the use of evidence-based information including:
1) A review of over 55,000 pieces of published scientific research
2) A systematic literature review
Accurate analysis of data
To accurately analyse the data for the review of the ADGs:
1) Nutrition and medical experts associated with the NHMRC to analyse data from the 55,000 published scientific research articles
2) Literature reviews were undertaken
Nutritional rationale of the Australian Guide to Healthy Eating
1) To promote and encourage good nutrition and health
2) To help prevent diet related and lifestyle diseases
