NUT 1104 Food Science I 2024 Fall Term - Lecture 3 - Proteins PDF

NUT 1104 Food Sciences I 2024 Fall Term Ezgi Pulatsu, Ph.D. School of Nutrition Sciences University of Ottawa/ Université d'Ottawa  2 Course Content Module 1...

NUT 1104 Food Sciences I 2024 Fall Term Ezgi Pulatsu, Ph.D. School of Nutrition Sciences University of Ottawa/ Université d'Ottawa  2 Course Content Module 1 Module 2 Module 3 Module 4 INTRODUCTION FOOD COMPONENTS and CHEMISTRY FOOD and FOOD MATERIALS FOOD ADDITIVES and FOOD SAFETY 3.1 Meat, Poultry and 4.1 Food Additives 1.1 Course Introduction 2.1 Water Fish 4.2 Food Safety Syllabus 2.2 Carbohydrates 3.2 Eggs and Dairy Course content 2.3 Proteins 3.3 Legumes, Pulses and Course calendar 2.4 Lipids Cereals Rules 2.4 Vitamins and 3.4 Flour and Pasta Regulations Minerals 3.5 Bread and Baked Goods 3.6 Chocolate  3 Course Calendar  4 Course Calendar Book 1) Essentials of Food Science, 5th Edition 2021 Vaclavik, Vickie, author.; Christian, Elizabeth W.;Campbell, Tad. Book 2) Fennema's Food Chemistry, 4th Edition, Kirk L. Parkin, Owen R. Fennema (Editors), ISBN: 9780429195273.3) Book 3) Understanding food: principles and preparation, Brown, A. C., Walter, J. M., & Beathard, K. (2015). Boston, MA, USA: Cengage learning.  5 Learning outcomes Become familiar with the chemistry and structure of proteins Understand the relationships between the chemical structure and properties Identify food proteins and their interactions with other molecules Discuss the importance of their functionality and stability  6 Outline Introduction Proteins Nomenclature Structure Chemistry Properties Enzymes and processing Summary What is the most abundant protein in human 7 body? Collagen → 30% of the total body protein (Abdollahi et al., 2018) link What is the most abundant protein in human 8 body? Collagen → 30% of the total body protein (Abdollahi et al., 2018) high nutritional value, favorable moisture performance, good biocompatibility, biodegradability (Veeruraj et al., 2015). Structure of collagen  9 Introduction Proteins are macromolecules with diverse biological functionalities in living tissues take part in energy production, food digestion, or muscle contraction can be plant or animal origin provide essential amino acids → sustain life and the body’s functionality must be extractable in high amounts and appropriate for further processing Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  10 Introduction Food proteins central terms – SHAPE and FUNCTION each type of protein has very specific tasks at molecular level Vilgis, T. A. (2023). Nutrition Biophysics: An Introduction for Students, Professionals and Career Changers. Springer Nature.  11 Vilgis, T. A. (2023). Nutrition Biophysics: An Introduction for Students, Professionals and Career Changers. Springer Nature.  Why there are so many different proteins with12 different properties? Countless possibilities due to several amino acid arrangements Muscle proteins in meats Connective tissue in proteins Globular muscle colorant proteins Spherical egg white proteins Rubbery elastic proteins from wheat grain, etc. Vilgis, T. A. (2023). Nutrition Biophysics: An Introduction for Students, Professionals and Career Changers. Springer Nature.  13 Why to consume protein-rich foods? To sustain function of our physiology build brain mass, organs, muscle mass and maintain them throughout our lives Animal origin proteins- most easily biologically available amino acid patterns of animal origin proteins --- similar to those of human Vilgis, T. A. (2023). Nutrition Biophysics: An Introduction for Students, Professionals and Career Changers. Springer Nature.  14 Vilgis, T. A. (2023). Nutrition Biophysics: An Introduction for Students, Professionals and Career Changers. Springer Nature.  15 Introduction Food proteins must be extractable in high amounts and appropriate for further processing highly complex polymers, made up of 20 different amino acids The term ”protein” is derived from the Greek word proteois, which means of the first kind. Fennema’s Food Chemistry, pp 237-351  16 Introduction Proteins contain 50%–55% carbon, 6%–7% hydrogen, 20%–23% oxygen, 12%–19% nitrogen, and 0.2%–3.0% sulfur on w/w basis, at the elemental level. Proteins are synthesized in the ribosomes cytoplasmic enzymes modify some of the amino acid constituents, altering the elemental composition Fennema’s Food Chemistry, pp 237-351  17 Introduction Proteins not enzymatically modified in cells are termed “homoproteins” and Proteins that are covalently modified or complexed with nonprotein components are referred to as “conjugated proteins” or “heteroproteins.” Nonprotein components → “prosthetic groups” Fennema’s Food Chemistry, pp 237-351  18 Introduction Examples of conjugated proteins nucleoproteins (e.g., ribosomes), glycoproteins (e.g., ovalbumin, κ- casein), phospho- proteins (e.g., α- and β-caseins, kinases, phosphorylases), lipoproteins (e.g., proteins of egg yolk, several plasma proteins), and metalloproteins (e.g., hemoglobin, myoglobin, cytochromes, several enzymes). glyco- and phosphoproteins contain covalently linked carbohydrate and phosphate groups, respectively while the other conjugated proteins are noncovalent complexes containing nucleic acids, lipids, or metal ions. Fennema’s Food Chemistry, pp 237-351  19 Introduction The amino acid constituents are linked in a linear sequence via substituted amide bonds (partial double bond). amino acid sequence in a protein can be rearranged in different sequences e.g., a small protein of 200 amino acid residues can be arranged in 20200 different sequences → diversity in functional and physiological properties due to different three- dimensional structure of each sequence Fennema’s Food Chemistry, pp 237-351  20 Introduction Based on their three-dimensional structure Globular proteins → exist in spherical or ellipsoidal shapes, resulting from folding or collapsing of the polypeptide chain(s) on itself. Fibrous proteins → rod- shaped molecules containing twisted linear polypeptide chains (e.g., tropomyosin, collagen, keratin, and elastin). They can be formed by linear aggregation of small globular proteins (e.g., actin and fibrin) Majority of enzymes are globular proteins, but fibrous proteins invariably function as structural proteins in bones, nails, tendons, skin, and muscles Fennema’s Food Chemistry, pp 92  21 Introduction Functions of proteins are diverse: enzyme catalysts, structural proteins, contractile proteins (myosin, actin, tubulin), electron transporters (cytochromes), ion pumps, hormones (insulin, growth hormone), transfer proteins (serum albumin, transferrin, hemoglobin), antibodies (immunoglobulins [Ig’s]), storage proteins (egg albumen, seed proteins), and toxins. found mainly in eggs and part of the defense mechanism in plant seeds → acting as act certain microorganisms, animals, and as sources of nitrogen and plants for survival against predators. amino acids for germinating seeds and embryos. Fennema’s Food Chemistry, pp 92  22 Introduction Food proteins may be defined as easily digestible, nontoxic, nutritionally adequate, functionally usable in food products, available in abundance, and agriculturally sustainable. Fennema’s Food Chemistry, pp 92  23 Introduction Some proteins do not contain all 20 amino acids. The structural and functional differences arise from the sequence in which the amino acids are linked together via amide bonds. changing the amino acid sequence, the type and ratio of amino acids, and the length of the polypeptide chain → result in billions of trillions of proteins with unique properties Fennema’s Food Chemistry, pp 92  24 Introduction Example Potato protein is rich in essential amino acids→ high biological value, but the amounts found in potato are negligible →challenging to isolate large quantities for commercial interest In contrast Whey proteins are rich in essential amino acids, can be easily collected during cheese manufacturing and processed to appropriate form for further use (e.g., whey protein powder). consumed with minimal processing from their natural source (e.g., a glass of milk or a steak) Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  25 Introduction Traditional sources of proteins are milk, meats (including fish and poultry), eggs, cereals, legumes, and oilseeds are mainly storage proteins 2050 world population → 9 billion --? critical need to develop non-traditional sources of proteins for human nutrition to meet the future demand Fennema’s Food Chemistry, pp 92  26 Introduction The need for high-quality protein with a suitable nutritional profile and functionality → new/alternative sources from microorganisms (microbial protein), insects, algae, or lab-grown protein (cultivated meat). Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  27 Introduction The factors limiting their broader use are poor (or unknown) technological functionality e.g., low water solubility, off-flavours, inadequate structure- formation properties, or problems with oxidative stability algae proteins → a fishy odour, and insect proteins → consumer acceptability Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  28 Amino acids Basic structural protein units → α-amino acids Building blocks of proteins α-amino acids consist of α-carbon atom covalently attached to a hydrogen atom, an amino group, a carboxyl group, and an R group (i.e., side chain) an amino group (–NH2), a carboxyl group (–COOH), a hydrogen atom, and a side chain (R–) linked to a carbon atom called α-carbon Fennema’s Food Chemistry, pp 238  29 Amino acids are chiral when R– is not hydrogen, which occurs only in glycine amino acids are found in enantiomeric forms D- and L- similar to carbohydrates most natural amino acids are in L- configuration in contrast to natural sugars found in D-form. Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  30 Amino acids Classification based on their interactions with water Nonpolar amino acids: contain mostly hydrocarbon R groups and do not have either positive or negative charges. There are two types of hydrocarbon side chains found in hydrophobic amino acids: aromatic 1 (i.e., tryptophan and phenylalanine) and aliphatic (i.e., glycine, cysteine, methionine, alanine, valine, leucine, isoleucine, and proline) Polar amino acids: have -OH and/or amide groups that may easily form hydrogen bonds with water (i.e., 2 serine, threonine, tyrosine, asparagine, and glutamine) Acidic amino acids: Negatively charged amino acids (i.e., aspartic acid, glutamic acid) 3 Basic amino acids: Positively charged amino acids at pH 7.0 and may interact with each other through 4 ionic interaction (i.e., lysine, arginine, histidine) 30 Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  31 Amino acids 31 Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  32 Amino acids 32 Image source: link  33 Amino acids 33 Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  34 Amino acids 34 Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  35 Amino acids Classification based on their nutritional significance ****A limiting amino acid is Essential amino acids: the body does not synthesise and must be an essential amino acid obtained from the diet (i.e., H, I, L, K, M, F, T, W, V). 1 found in insufficient quantities in foods. Most plant proteins have a limiting Non-essential amino acids: (i.e., A, D, N, E, S) amino acid. For example, 2 lysine in grains, nuts, and seeds, threonine in grains, Conditionally essential amino acids: essential in the human diet methionine in beans, and under certain circum- stances, e.g., disease or early development (i.e., tryptophan in corn. 3 R, C, Q, G, P, Y) Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  36 Amino acids 36 Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  37 Amino acids Their ionization state is dependent on pH → they are called amphoteric, meaning that they can react as acids or bases and form zwitterions (dipolar ions) At acidic conditions (pH is low)→ amino group is ionized and carries (+) charge At alkaline conditions (pH is high) → carboxyl group is ionized and carries (-) charge Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  38 Amino acids The isoelectric point (pI) → the pH value at which amino acids have a net charge of zero. Depending on its structure and the pKa values of each amino acid, the pI value changes (the transition from positively to zwitterion to negatively charged) Amino acids have up to three pKa values for: 1. the α-carboxyl group (pKCOOH), 2. the α-amino group (pKNH3+) and 3. the side chain (pKR). e.g., alanine with pKCOOH = 2.4 and pKNH3+ = 9.7 Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  39 Amino acids Example Alanine with pKCOOH = 2.4 and pKNH3+ = 9.7 At pH= 1, alanine is positively charged due to the pH < pKCOOH and pKNH3+. If NaOH is added to increase the pH from 1 to above 2.4 At pH > 2.4, the hydrogen from the α-carboxyl group dissociates and the amino acid holds a negative charge in addition to the positive charge that was already present in the structure Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  40 Amino acids 2.4< pH< 9.7, alanine exists as a zwitterion, and the net charge is nearly zero. If we continue to add NaOH to increase the pH until the pH is just above 9.7. pH> 9.7, dissociation of hydrogen from the α-amino group results in loss of the positive charge and the amino acid has a net negative charge. Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  41 Amino acids Isoelectric point calculation for amino acids: Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  42 Amino acids Peptide bond→ special bond between amino acids formed between the α- carboxyl and α-amino groups of two amino acids (same or different) and proceeds via a condensation reaction (i.e., loss of water) After the peptide bond formation, one end of the newly formed molecule carries the -NH2 group (N-terminal) and the other the -COOH group (C-terminal). N-terminal is on the left and C-terminal on the right → convention. Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  43 Amino acids When amino acids are incorporated into proteins, the α-carboxyl and α-amino groups have already reacted in the formation of the peptide bond, and therefore, they are not available for further reactions. That’s why only the side chains are available for reactions. Peptide bond formation, disulfide bond formation, and Schiff base formation are the most relevant reactions. Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  44 Amino acids- peptide bond formation Dipeptide→ two amino acids are linked through a peptide bond Tripeptide → three amino acids are linked through a peptide bond, Polypeptide → as a guideline, when up to ~50 amino acid residues are linked, the chain is termed as polypeptide If more than ~50 → protein formation. Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  45 Amino acids- peptide bond formation Peptide formation during fermentation contributes to flavor (undesirable or desirable) Bitter peptides can be formed (e.g., the tripeptide leucine-leucine-leucine), Bioactive peptides may also be formed or be naturally present in foods and may possess health benefits (e.g., casein hydrolysates) Sweet taste such as the dipeptide aspartame and neotame, and are used as artificial sweeteners Bacteriocins are peptides or small proteins with antibiotic properties. Nisin is an approved bacteriocin used as a food preservative. Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  46 Amino acids- disulfide bond formation The sulfhydryl group (-SH) of cysteine is highly reactive, and -SH groups of two cysteines oxidize easily and form cystine disulfide bond or disulfide bridge Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  47 Amino acids- Schiff base formation Free amino groups of amino acids may react with aldehydes or ketones → imines (Schiff base) A chemical compound containing a carbon-nitrogen double bond Very frequent in foods, the presence of amino acid and a reducing sugar, this reaction happens Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  48 Proteins- classification Structural proteins are fibrous proteins such as keratin or collagen found in the skin or connective tissues of animals Collagen, after appropriate processing, is converted to gelatin → a commonly used food ingredient Contractile proteins such as myosin or actin are found in muscle tissues → responsible for muscle contraction Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  49 Proteins- classification Storage proteins (egg albumen, seed proteins, or milk proteins) most proteins used in the food industry Protective proteins (toxins, allergens) → important for allergic individuals (e.g., soy or gluten peptides) or in case of toxins that they cause disease (e.g., botulism) Hormones (e.g., insulin or growth hormone), transfer proteins and antibodies are proteins responsible for different metabolic activities in the body but no functionality in food formulation. Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  50 Proteins Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  51 Proteins- classification Depending on their solubility (Osborne protein classification of storage proteins): Albumins are soluble in neutral salt-free water Globulins are soluble in neutral salt solutions Glutelins are soluble in dilute acid or alkaline solutions Prolamins are soluble in 50–90% ethanol. Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  52 Proteins- classification Depending on their solubility (Osborne protein classification of storage proteins): Glutenin and gliadin, the main protein fractions of gluten, are important examples of food proteins insoluble in water. Instead, upon hydration strong gluten network is formed. Glutenin is soluble in dilute acids (i.e., it is a glutelin) while gliadin is soluble in ethanol (i.e., it is a prolamin). Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  53 Proteins- structure 1. Primary 2. Secondary 3. Tertiary 4. Quaternary The specific The three- Proteins with > The sequence of geometrical dimensional one chain may amino acids in arrangement of structure of have a the polypeptide the polypeptide proteins, in quaternary chain chain along one which the structure that is axis and is due polypeptide the number and to hydrogen chains are arrangement of bonding tightly folded multiple protein between and packed into subunits in a peptide bonds. a compact form complex Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  54 Proteins- structure Major types of secondary structures are α-helices and β-pleated sheets. Two common types of tertiary structures: fibrous and globular Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  55 Proteins- structure Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  56 Proteins- structure Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  57 Proteins- structure Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  58 Proteins- structure Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  59 Proteins- structure Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  60 Proteins- structure Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  61 Proteins- structure The proteins with more than one chain (can have quaternary structure) are composed of oligomers (macromolecular complexes composed of non-covalent assemblies of two or more monomer subunits). Monomer subunits have hydrophobic interactions to form dimers, trimers, or tetramers for two, three or four monomers. Β-conglycinin and glycinin from soybeans or β- lactoglobulin from milk are the examples of such proteins. Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  62 Proteins- structure Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  63 Proteins- denaturation and hydrolysis Processing, storage, or food digestion alter the protein structure. Denaturation is defined as the loss of secondary, tertiary, or quaternary structure of proteins, resulting in protein unfolding. It is important to note that denaturation does not involve peptide bond cleavage and frequently, but not always, is reversible. Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  64 Proteins- denaturation and hydrolysis Coagulation or gelation → the random aggregation of denatured protein molecules due to protein-protein interactions pH or T change (two most common denaturation methods) As protein unfolds→ hydrophobic amino acids buried in the structure are now exposed that can interact through hydrophobic interactions, which results in gel formation. E.g., the coagulation of milk proteins during yoghurt manufacturing (pH is lowered) and heat-induced denaturation of egg proteins Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  65 Proteins- denaturation and hydrolysis Denaturation of proteins → loss of biological activity (important for enzymes) Inactivation of enzymes by heat treatment e.g., blanching is a low- temperature heat treatment to denature enzymes naturally present in vegetables before freezing Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  66 Proteins- denaturation and hydrolysis Denaturation of proteins → increase bioavailability of amino acids enzymes in GI tract can easily digest the denatured protein Denaturation of proteins → improve the emulsification and foaming capacity of proteins Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  67 Proteins- denaturation and hydrolysis ***Particulate gels (like yogurt) → opaque and have low water-holding capacity ***Fine stranded gels (like gelatin) → translucent and have high water-holding capacity Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  68 Proteins- denaturation and hydrolysis Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  69 Proteins- denaturation and hydrolysis Protein hydrolysis involves cleavage of peptide bonds resulting in smaller polypeptides or free amino acids Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  70 Proteins- denaturation and hydrolysis Protein hydrolysis can be due to the action of acid and heat (acid hydrolysis) or proteolytic enzymes (enzymatic hydrolysis) What is the major difference between acid hydrolysis and enzymatic hydrolysis ? enzymatic hydrolysis cleaves only one bond, always resulting in the same products acid hydrolysis is random process and conditions (duration, temperature, pH, type of acid, etc.) certainly change the end products Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  71 Proteins- functional properties Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  72 Proteins- functional properties Unfolding of protein exposes the hydrophobic amino acids towards the hydrophobic phase which allows the protein to adsorb. Adsorption vs Absorption Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  73 Enzymes Are made up of proteins Catalytic activity → they speed up the reactions Can accelerate the reaction they catalyse, but they are not consumed Once denatured, they cannot function. e.g., blanching of vegetables Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  74 Enzymes are naturally found in foods are important in the food industry can be detrimental or desirable to quality browning of fruits and vegetables inactivation is necessary to prevent oxidation during fermentation, desirable product characteristics cheese, salami, or pickles Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  75 SUMMARY Amino acids are building blocks of proteins Proteins are most stable at their isoelectric point (net charge is equal to zero) Transformation of a protein from a native folded state to an unfolded state → protein denaturation.  76 SUMMARY Image Source: link  77 SUMMARY Change in physical properties, such as UV absorption, fluorescence, sedimentation coefficient, and viscosity, as a function of denaturant concentration → monitoring the protein denaturation. Temperature, extremes of pH, pressure, organic solvents, organic solutes, and chaotropic salts → denature the protein Protein hydrolysis involves peptide bond cleavage Protein functionality Enzymes  78 Summary of amino acids Amino acid Abbrev. Side chain Aspartic acid Asp negative H Y Glutamic acid Glu negative D Arginine Arg positive R O Lysine Lys positive P Histidine His positive H Asparagine Asn uncharged I L Glutamine Gln uncharged I Serine Ser uncharged C Threonine Thr uncharged Tyrosine Tyr uncharged  79 Summary of amino acids Amino acid Abrev. Side chain Alanine Ala nonpolar H Y Glycine Gly nonpolar D Valine Val nonpolar R O Leucine Leu nonpolar P Isoleucine Ile nonpolar H Proline Pro nonpolar O B Phenylalanine Phe nonpolar I Methionine Met nonpolar C Tryptophan Trp nonpolar Cysteine Cys nonpolar  80 Next Topic… 2.4 Lipids  81 References  82 Any questions? Contact information: Office hour: [email protected] Ezgi Pulatsu, PhD Tue 12.00-1.00 pm (Teams-online, the link is on [email protected] [email protected] syllabus and Brightspace) Or By Appointment