Food Science Notes PDF

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Food Science NotesExam 1 Introduction: what is food 01 - What is food - Plants and animals - In terms of chemistry - Water - Carbohydrates - Proteins - Lipids - Minerals - Vitamins - What else is in food? - Microorganisms - Pesticides - Antibiotics - Environmental pollutants - Food additives - Subst...

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Food Science Notes Exam 1 Introduction: what is food 01 - What is food - Plants and animals - In terms of chemistry - Water - Carbohydrates - Proteins - Lipids - Minerals - Vitamins - What else is in food? - Microorganisms - Pesticides - Antibiotics - Environmental pollutants - Food additives - Substance added in food to form specific functions - Food additives - Attractive → colors, flavors - Nutritious → added vitamins and minerals - Make and/or keep the structure → leavening agents - Make and/or keep the structure → gelling agents - Increase the shelf life → food preservatives - How can we find them - Read the ingredient list - What else is processed food? - During processing - Physical contaminants - E.g. metals/glass from equipment - E.g. human hair from workers - Chemical contaminants - E.g. sanitizer residues - Microbial contaminants - E.g. bacteria from worker’s hands - Food Raw materials - Processed food products - Top ten problems for the next 50 years - Energy - Water - Food

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- Environment - Poverty - Terrorism and war - Disease - Education - Democracy - Population Food waste - At farm, crops go unharvested because of they are ____? - A. not in perfect color - B. not in perfect size and shape - C. damaged by pests - D. all of them - Answer: D

Introduction: why does food go bad 02 - What do you mean “bad”? - Food quality - Food is spoiled to the point in which the sensory attributes are no longer accepted - Food safety - Foodborne illnesses - Food quality/safety - Appearance → not fresh - Appearance → got moldy - May also produce mycotoxins - Texture → hard like a rock - Smells funny - Tastes funny - Your food may look ok, but it might not be - Why does food go bad? - Physical - Chemical - Microbial - Physical - Hard like a rock → loss of moisture - Chemical - Smells funny - E.g. oxidation → rancidity - Biochemical - Not fresh → enzyme - Microbes - Mold → 10 -100 um - Yeast → 3-5 um

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- Bacteria → 1-3 um - Virus → 50 -100 nm Bacteria - One of the leading reasons for foodborne illness - Bacteria cells reproduce very quickly Bacterial spores - Highly resistant to harsh conditions Top bacteria species related with foodborne diseases - Salmonella - Shiga toxin produced escherichia coli - Listeria Salmonella - Widely dispersed in nature - Every year, salmonella is estimated to cause one million foodborne illnesses in the united states with 19,000 hospitalizations and 380 deaths - Food sources → eggs, poultry, meat, etc - Symptoms → diarrhea, fever, abdominal cramps, vomiting - Incubation period: 12-72 hrs - Duration of illness: 4-7 days - Infection dose: 1,000 - Huge outbreak linked to peanut butter Why this pattern? - Peanuts as an ingredients used in many products - Long shelf life food Escherichia coli - E. coli is the name of a type of bacteria that lives in your intestines and in the intestines of animals. Although most types of E. coli are harmless, some types can make you sick Shiga toxin producing E. coli - Certain types of E. coli (e.g. O157:H7) makes a toxin called shiga toxin - Causes bloody diarrhea and can sometimes cause kidney failure and even death - Minimum infection dose: 1 cell Listeria - The name of a bacteria found in soil and water and some animals, including poultry and cattle - It can be present in raw milk and foods made from raw milk - It can also live in food processing plants and contaminate a variety of processed meats - Unlike many other germs because it can grow even in the cold temperature of the fridge Facts and symptoms - An estimated 1600 people get listeriosis each year, and about 260 die - Listeriosis; headache, stiff neck, confusion, loss of balance, and convulsions in addition to fever and muscle aches

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Pregnant women are approximately 20 times more likely than other healthy adults to get listeriosis, lead to miscarriage, stillbirth, or life-long health problems - FDA regulations - Listeria and E.coli O157 and Salmonella are zero-tolerant in ready to eat foods - No detectable level of viable organisms allowed - Viruses - Smallest microbes - They are only able to multiply inside the cells of other living things - Norovirus is the leading cause of illness and outbreaks from contaminated food in the united states - About 50% of all outbreaks of food-related illness are caused by norovirus - Causes 20 million cases of illnesses per year in the US - Food sources - Foods that are commonly involved in outbreaks of norovirus illness are - Leafy greens (such as lettuce) - Fresh fruits - Shellfish (such as oysters) - Over 90% of diarrheal disease outbreaks on cruise ships are caused by norovirus - How many norovirus particles are needed to make people sick? - A. 1 - B. 20 - C. 100 - D. 1000 - Answer: B - How can we prevent food poisoning? - In the food industry, how can we preserve food from going bad? - Adding food additives - Food processing - Food preservation - Preventing enzymatic browning - Blanching + freezing → inactive enzyme and slow down enzyme activity - Preventing mold - Milk pasteurization + refrigeration → reduce bacteria cells and slowing down the growth - Canning + sterilization → kills all the bacterial cells and spores Water 03: - Food compositions - Water - Carbohydrates - Protein - Lipids - Vitamins and minerals

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Water covers 71% of the Earth’s surface Three forms: liquid, ice, gas Water - It is vital for all known forms of life - We are ~60% water - We drink water - Also animals, plants, microbes Water is the major components of our food We use water to produce our food Tap vs. bottled water Tap is regulated by the EPA and bottled is regulated by the FDA - Both equally safe - EPA has more regulations Which statement is true? - A. Bottled water is more safe than tap water - B. bottled water tastes better than tap water - C. Bottled water is more expensive than tap water - Answer: C Slowing down water loss - Put in a package Water and food safety - Microbes like water too - Water activity (aw) → the availability of water in food Water activity - Water can bind on foods - The more the food is bond the less microbes there are Water content vs. water activity - You can have the same amount of water in two packages while having different water activities - It depends on if the water is bound Control by water activity - Drying of foods - Sugar addition - Salt preservation of meat and fish has been practiced over the ages Preserve food by lowering water activity - Fresh meat → water activity = 0.95 - Meat jerky → water activity = 0.8 - Vegetables and fruits → water activity = 0.85 - 0.95 - Dried → water activity = 0.5 - 0.6 - Milk → water activity = 0.95 - Milk powder → water activity = 0.2 - Juice → water activity = 0.98 - Jelly (pectin + sugar) → water activity = 0.8 - Sugar absorbs water

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Water and pH - Pure water 10-7 moles/L - Negative logarithm of the hydrogen ion concentration in moles/L - Pure water: pH = 7 - Acid: pH below 7 - Base: pH above 7 - Microbes can only grow within a range of pH -

Carbohydrates 04: - Carbohydrates - Carbohydrates are ‘hydrates of carbon’ - Carbohydrate-rich foods: plant food - Two types of carbohydrates - Simple sugars - Complex polysaccharides (starch, dietary fiber) - Simple sugars: monosaccharides and disaccharides - Monosaccharides are single sugar molecules - Glucose - Fructose - Galactose - Disaccharides consist of two sugar molecules - Sucrose - Lactose - Maltose - The ‘ose’ ending identifies a simple sugar - Monosaccharide structure - Fructose: fruit sugar - Glucose: blood sugar - Disaccharide structure - Sucrose = Glu + Fru (table sugar) - Lactose = Glu + Gal (milk sugar) - Maltose = Glu + Glu (starch breakdown) - Sucrose → table sugar - Canes and beets - White sugar + molasses - No significant nutrition difference - Lactose Intolerance - Small intestine - Lactose lactase----> Glucose + Galactose - With lactose intolerance - Large intestine - Lactose bacterial action----> Gas, Diarrhea - Complex carbohydrates

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- Chains of sugar molecules - polysaccharides Two types of complex carbohydrates - Starch which is digestible - Fiber which is not digestible Starch properties: gelatinization - Gelatinization: thermal processing of starch granules in water causes swelling, bursting and release of starch molecules (amylose and amylopectin) 2 classes of dietary fiber - Dietary fiber can be classified as soluble or insoluble - Soluble fiber (pectin, gume) will dissolve in water, yielding a clear solution - Ex. benefiber - Insoluble fiber (cellulose) will not dissolve in water and resembles small cereal flakes - Ex. wheat bran - *Plant tissue contains a mixture of soluble and insoluble fiber Dietary fiber in the foods we eat - The average American should consume 25-35 grams of fiber per day Which statement is not true about fiber? - A. fiber is indigestible - B. soluble fiber can lower cholesterol and help control blood sugar level - C. insoluble fiber can help soften stool and reduce intestinal disease - D. fiber supplement is recommended for normal healthy people - Answer: D Ways to increase fiber in your diet - Eat more fruits and vegetables - Eat the skin or fruits and vegetable - Include legumes in the diet - Choose whole grains - Avoid foods that are highly processed Function of carbohydrates in foods - Carbohydrates contributes sweetness and texture to foods - Sweetness is provided by simple sugars - Both simple sugars and polysaccharides (starch and fiber) can contribute texture Top two on the sweetness ranking - #1 fructose - #2 HFCS Which statement is not true about table sugar and HFCS? - A. both become glucose and fructose after digestion - B. HFCS will cause obesity while table sugar won’t - C. HFCS is cheaper than table sugar - HFCS is sweeter than table sugar - Answer: B Carbohydrates providing texture - Thickening, gelling, stabilizing

- Binding water Proteins 05: - Protein - Made of amino acid - Protein and nutrition - Essential amino acids - Provide calorie (4 cal/g) - Foods high in protein - Meat and fish - Cheese - Eggs - Beans - Bread - Hummus - Nuts and seeds - Protein 3D structure - Looks like curls - Spirals - Protein denaturation - Loosens the spirals - Lineralizes it - Denaturing protein in cooked food - Make the digestion easier - Kill the harmful microbes - Denaturing the protein of microbes - What doe the Maillard reactions produce? - A. amino acids - B. proteins - C. sugar - D. flavors and brown color - Answer: D - What temperature does the Maillard reaction work the best? - A. 100 to 200 - B. 230 to 340 - C. 350 to 400 - D. 400 to 450 - Answer: B - Maillard reaction is favored at - A. neutral pH - B. acid pH (lemon juice) - C. base pH (baking soda) - Answer: C - Other biological functions - Deliver other nutrients like iron, calcium

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- Casein - milk protein Enzymes (are proteins too) - Digest food - Lactose Intolerance - Small intestine - Lactose lactase----> Glucose + Galactose - With lactose intolerance - Large intestine - Lactose bacterial action----> Gas, Diarrhea - Protease digests protein - Lipase digests lipid (fat) - Make food - Milk clotting enzyme, rennet - What’s the required protein concentration in raw milk to make cheese? - A. 1% - B. 2% - C. 3.3% - D. 3.8% - Answer: - The liquid that is separated from cheese contains? - A. casein - B. calcium - C. lactose - D. salt - Answer: - Make food go bad - Polyphenoloxidase, making fruits go brown - Make specific flavor - Enzymes can be inactivated by heating → protein denaturation - Raw vegetables are more bitter than cooked, why? Once damaged myrosinase---------> bitter compounds - The flavor produced during cutting or crushing the onion and garlic is produced by enzyme alliinase - The enzyme is only active when you are cutting or crushing them - Ways to chop onions without tears - Inactivate the enzyme - Vinegar on the cutter and chopping board - Slow down the enzyme reactions - Chill the onion for 15 min before chopping - Use a fan - Chop in water Antibody, immunoglobulin - Proteins too Protein and food allergy

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Food allergy is an abnormal response to a food triggered by you body’s immune system (immunoglobulin E, IgE) - More than 160 allergen producing foods are now known - Most allergens are proteins - The big eight are tree nuts, shellfish, wheat, fish, milk, eggs, soy, peanuts Allergic reactions to food can range from mild to life-threatening (anaphylaxis) - Hives - Shortness of breath - Swelling - Vomiting and/or stomach cramps - Anaphylaxis - epinephrine auto-injector Peanut allergenic proteins - At least 11 peanut allergenic protein have been identified Peanut allergenic proteins - Roasting peanuts make it worse - Protein more resistant to digestion - Only a dust of protein can cause reaction Importance to food industry - Food products recalls - 1. Pathogen contamination - 2. Chemical residue - 3. Undeclared food ingredients that are in the big 8 allergens - #1 cause for food product recall Why they are in the food? - Foreign ingredient in food - Cross contact - Undeclared egg was found in ~50% of the finished ice cream products and undeclared peanut in 10% of them, the cause being cross contact of equipment - A FDA case study for ice cream manufacturers in Minnesota and Wisconsin Gluten intolerance - Gluten is a protein of wheat, barley, and rye - Gluten intolerance is associated with celiac disease - This reaction produces inflammation in the small intestine, causing weight loss, bloating and sometime diarrhea - This abnormal response does not involve IgE antibody and is not considered a food allergy Gelatin - Made from animal tissue collagen (a protein_ - Used as a gelling agent in food industry - Properties - Setting point: 2-5 C - Melting point: 25 - 30 C

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Unique property: the melting point is below 37 C so they melt in the mouth to give smooth textures with excellent flavor release

Lipids 06: - Lipid - Fat - Oil - Lipids - Do not mix with water - Form boundaries between cells - Structure - Triglycerides - 96% of lipid structure is food -

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- More saturated fat → less unsaturated fat - Less saturated fat → more unsaturated fat Hydrogenation - Hydrogen is added to the fat to saturated double bond -

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Plant -

Hog → lard Beef → tallow Milk → butterfat Fish → cod liver oil Soybean Olives Peanuts

Saturation and melting point

Produce trans fat during the process Source Animal

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- Corn - Canola What’s the function of the vibrating bin? - A. to separate leaves and twigs - B. to separate the large and small olives - C. to separate olives of different colors - D. to soften the skin of olives - Answer: A After the oil is extracted from the paste, it is called…..? - A. virgin olive oil - B. refined olive oil - C. olive oil - Answer: A Olive oil grades - U.S. Extra Virgin Olive Oil for oil with excellent flavor and odor and free fatty acid content of not more than 0.8 g per 100 g (0.8%); - U.S. Virgin Olive Oil for oil with reasonably good flavor and odor and free fatty acid content of not more than 2 g per 100 g (2%); - U.S. Virgin Olive Oil Not Fit For Human Consumption Without Further Processing is a virgin (mechanically-extracted) olive oil of poor flavor and odor U.S. Olive Oil is a mixture of virgin and refined oils; - U.S. Refined Olive Oil is an oil made from refined oils with some restrictions on the processing. Lipids and nutrition - Provide calorie - 9 cal/g - Produce essential fatty acids - Omega-3 and omega-6 - Transport fat soluble nutrients - E.g. vitamin A,E,D,K Which one is good which one is bad - Saturated fat - ok if not too much - Trans fat - not good at all - Omega 3 unsaturated fat (DHA and EPA) - Omega 6 unsaturated fat (Linoleic acid) - Conjugated linoleic acid Health Problems: Trans-Fats - Increased health risks - Coronary heart disease - Cancer - Obesity - Diabetes - It is now required to remove trans-fat from food products Omega-3 and omega-6 - For millions of years humans existed on a diet consisting primarily of

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fresh fruits, leafy vegetables and meat. A diet that provided 1:1 ratio of omega-6 to omega-3 PUFA. - Over the past 150 years there has been significant change in the composition of the food supply of western societies due to the promotion of vegetable oils as the source of UFA. - Today, the ratio of omega-6 to omega-3 in North American diet is estimated to range from 10:1 to 25:1 Balancing w-3 and w-6 fatty acids - 20: promate inflammation → vegetable fats w-6 - 1: reduce inflammation → marine animals, algae w-3 - Imbalance in “western” diet -------> rising rate of inflammatory disorder - Recommended 2:1 omega-6 to omega-3 - Source: milk and meat Potential benefits:

- Anti-obesity effects - Prevention of cardiovascular disease - Cancer preventive effects - Improve bone health - Modulate immune and inflammatory responses Safety considerations for CLA use - Influence liver functions - Milk fat depression - Glucose metabolism - increased insulin resistance by CLA (but may be transient) - Oxidative stress Sensory functions of fat in products - Appearance → gloss, translucency, color, surface uniformity, crystallinity - Texture → viscosity, elasticity, hardness - Flavor → intensity of flavors, flavor and aroma release, flavor profile, flavor development, time intensity relationships - Mouthfeel → meltability, creaminess, lubricity, thickness, degree of mouth coating

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Lipid function in food processing - Used as a cooking medium Which statement is NOT true for the smoking point of oil? - A. smoking point is when the oil breaks down to airborne compounds - B. airborne compounds are flammable - C. oil reaches its smoking point can burn - D. we need to wait until the oil reaches smoking point before cooking - Answer: D Why we cannot directly put frozen turkey into flying? - A. Water and oil doesn’t mix, so the water pushes the oil particles to bubble and quickly ignite - B. Water prevents the oil to fully cook the turkey - C. It takes too long to direct frying the frozen turkey - D. The texture of the turkey is not good if you directly put frozen turkey - Answer: A Lipid oxidation - Lipid oxidation is a complex series of chemical reactions that is initiated when oxygen interacts with unsaturated lipids - Nutrition - Loss of nutrients - Formation of toxic reaction products - Food quality - Off flavors (randicity) Big problem in food industry - Solutions - Vacuum package - Carbon dioxide and nitrogen - Oxygen absorbers - Food additives - Interactive with O2 faster than lipids - Break the oxidation reaction More natural? Choices - Tocopherol - vitamin E - Rosemary extract - Containing natural vitamin E and other antioxidant Why fat replacement? - High fat diets are linked to obesity and cardiovascular disease - RDA for fat is 30% of calories - Current consumption is somewhere near 38% Fat replacers - Carbohydrate-based - Protein-based - Lipid-based - Low-calorie fats

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- Synthetic fats Carbohydrate based fat replacers - Complex carbohydrates: starch and fiber - Mimic smoothness or creaminess of fats in foods primarily by moisture retention and bulkiness of their solids - Used a lot in cakes, dessert mixes, candies, frozen desserts, puddings, and salad dressings Example - Kraft’s earliest success at fat reduction, introduced in 1930’s - Using a starch...