Gate XE Notes (Food Eng) PDF

# Important Points Gate XL-2024 ## **Important Points Gate XL-2024** ### **Fick's law for molecular diffusion** - $J = -D \frac{dc}{dx}$ where, J = diffusion flux D = Diffusion coefficient (m2/s) dc/dx = concentration gradient ### **Characteristics of fungal cell wall** - Histone proteins = framework/rigidity - β-glucans = polymer of glucans - Chitin = N-acetyl glucosyl amine ### **HFCS from corn starch** - Amylase = starch to glucose (hydrolysis) - Glucoamylase = starch to glucose - xylose isomerase = glucose to fructose (β-(1-4) (1-6) bonds broken) ### **Mycotoxins** - Aflatoxin = wheat common fungi/carcinogenie - Ochratoxin = Aspergillus niger and ochraceus (grains and coffee) ### **At a given temperature drying (desorption) exhibits higher adsorption than adsorption.** - EMC = Water binding. - Critical limit = Interaction blw surface and adsorbing substance. - HACCP = Food safety. - CCP = Control point. - Monitoring = corrective action - Record keeping = Verification ### **Gate 2023 Missed Concepts** - **Extrusion steps** - Feeding - Kneading - Cooking = expansion - **Amylose (α(1-4))** - contributes to gelatin property. - linear structure - glycosydic linkage - D-glucose units - less soluble than amylopectin. - affinity to granules ### **Amylopectin** - α-D glucose linkages in chains and α(1-6) linkages at branch points. - Viscosity and thickening property of starch. - More soluble as it is branched (70-80% of starch) - H2 bonding with water ### **Under standard assay conditions** - 1U = 1 μmol/minute ### **Thermo-sin** - Cheese manufacturing - Coagulation of milk during cheese production ### **Thermolysin** - Aspartame synthesis - Acyl glycerol restructuring ### **Vinegar** - Acetobacter aceti ### **Citric Acid** - Aspergillus niger ### **Lysine** - Corynebacterium glutamicum - E. coli ### **Prolonged fermentation of cocoa seeds leads to ‘off-flavor’ due to the release of SCFAs.** ### **Gate Food Technology (Mock) (Cav-India)** - 36 chapter test - 545 questions ### **Iodine test is used to detect starch as an adulterant in milk and milk products. ** ### **Carbonyl group + a free amino acid to form an aldehyde. ** - Strecker degradation ### **Pyranose and furanose rings open up by: ** - Pyrolytic reaction to form furfural derivatives. - (caramelization). ### **An L-isomer of monosaccharide formed in the body is xylulose (Pentose).** ### **Pentose sugar** - Ribose and deoxy-Ribose - Trehalose = two units of glucose. (α-D glycosidic α(1-1) linkage) ### **Cellobiose/maltose** - Disacaccharide - (β-D glycosidic α(1-4) linkage) ### **Hyaluronic acid** - Heteropolysaccharide ### **Haltose** - α-D glucose units - α(1-4) linkages ### **During gelatinization** - Loss of organized structure. - Increased viscosity - Increased susceptibility to digestion - Increased permeability of water. ### **Retrogradation occurs due to crystallization of amylose occurring quicker than amylopection.** ### **α-D and β-D glucose are anomers.** - Anomeric carbon. ### **Cellulose** - Trees - β-D glucopyranose (β-1-4) linkage ### **Lignin** - Stores of fruits/cereals. ### **Inulin** - Chicory ### **Glucose + Galactose (β-(1-4)) - Lactose** ### **Melibiose** - α-(1-6) disaccharide - (Glucose) + (Galactose) ### **Non-reducing sugars** - Trehalose - Stachyose - Raffinose - Verbaskose - α-glucose (α(1-1) bond) - Tetrasaccharide - Pentasaccharide ### **Papain** - Protease ### **Rennin** - Aspartic protease ### **Lactase** - Glucoamylase ### **Aspergillus niger** - Enzymes were discovered in Yeast – fermentation. ### **Co-factors:** - Inorganic Ions (Mg+2/Zn+2) - Organic molecules. (NAD+/FAD) ### **[S] = Substrate concentration.** - Much higher in the beginning compared to product. - Can be treated as constant. ### **Types of inhibitors and their effect** - **Competitive** - [Km] ↑ (Vm) ↓ - **Non-competitive** - [Km] cons. (Vm) ↓ - **Uncompetitive** - [Km] ↓ (Vm) ↓ - **Mixed** - [Km] ↑ ↓ (Vm) ↑ ↓ ### **Biopolymers can be microbiologically produced and act as gelling agents.** - Xanthan gum/Alginate/Chitosan ### **Amyloglucosidase can catalyze both α(1-4) and α(1-6) linkages.** ### **Lipoxygenase** - Capable of catalyzing FFA and monoglycerides. ### **[S] = [2 X 10-5] [K]m = [5 X 10-3] [S] < [0.004] < 0.01 first order reaction.** - 10 Inz = kT 0.693 = k 0.115 /min T 6 ### **Enzymes** - Epoylase/Hexokinase/Glucose-6-phosphatase - Cofactor (Mg+2) - Glutathione peroxidase ### **JFHAC-** ### **Microbial enzyme** - Glucoamylase - Protease - Xylanase - Glucose isomerase - Catalase - Asparaginase - Thermolysin ### **Applications** - HFCS/beer production - Softening of doush/meat tenderization. - Clarification of fruit juice. - PIFCS = prior to cheese production. - removal of H2O2 from milk (baking). - Reduction in formation of acrylamide. - Aspartame. ### **Enzymatic browning** - also takes place in seafood. ### **Naringinase** - Debittering enzyme used in citrus fruit juices. ### **Animal fat is rich in saturated fatty acids and poor in Poly-unsaturated fatty acids. ** ### **Simple lipids** - Fats/waxes/Isoprenoids. - Fatty acids - Derived lipids. ### **Complex lipids** - phospholipids - Glycolipids (Glycosphingolipids) ### **CH3 at left (C9-10) (C01) -- Lipid** ### **Derived Lipids** - Ketone bodies - Steroids - Lipid-soluble vitamins ### **BHA** - prevents rancidity and off odour. ### **Calcium propionate** - mold and bacterial growth. ### **Oxidation in fats and oils are prevented by** - Propyl gallate ### **Melting point of fats increase with chain length and decrease with degree of unsaturation.** ### **Principal antioxidants in vegetable oil** - Soybean oil = tocopherol and vitamin E. - Inherently present: - Diterpenoid = Retinol - Tetra-terpenoid = Carotenoid ### **Saponification number:** - ¼ Avg mol wt of fatty acids present. - SCPA in fat in a sample. - L = number of 1g KOH required - LMFA = Free fa in sample. - Acid number = ### **Hydrolytic rancidity. ** - This hydrolyzed = fat + glycerol. - No enzyme involved. ### **Avidin & pyrithiamine = Anti-vitamin** ### **Total calcium in kgus = (lky)** ### **Chemical score of milk protein is (CS)** ### **Functional Food = Nutraceuticals (example: iodised table salt)** ### **[bacteria] can be estimated by Lactobacillus leichmanni.** ### **Dietary guidelines are used to lesser the incidence of chronic killer diseases.** ### **DRI = Dietary reference intake = Diet planning.** ### **Most common vitamin deficiency = Folic acid (vit -B-9) (Digestive-U/F) (D - Fecal).** ### **BV% = % of ingested protein/nitrogen in the body x 100% of the protein.** ### **Fenugreek seeds are rich source of saponins, yamogenin/gitogenin/figogenin** ### **Bowman Birk trypsin inhibitor = ** soy bean. - Inhibits only trypsin. - Kunitz type. - Inhibits both trypsin and chymotrypsin. ### **Betalains =** plant pigments from tyrosine ### **Catalase & hemo grubin =** both have porphyrin ring ### **Largest known protein =** Titin (human body) - Most abundant = Collagen (1) Keratin (2) ### **Disulfide bonds** = stabilize extracellular protein. ### **Gelatin =** hydrolyzed protein. - Fibrils = peptides ### **Veri green process =** vegetable blanching - 2 nt2/cu ions used = greener ### **Hemoglobin (Both proteins)** - 8 alpha helix - Muscle cells ### **Myoglobin** - 8 alpha helix - monomer - 02 storage ### **Tetratrame (2 α,2β)** - 02 transport - 4 O2 binding sites - 1 O2 binding site. ### **Frozen Foods** - must contain less amylose and more amylopectin. - Quality loss, if high amylose - gel formation = syneresis when reheated. ### **When a fined mass of air-water vapor mixture is heated at constant pressure** - const (not net addition). - RH = Specific Humidity. ### **During sensible cooling of air with 60% relative humidity ratio remains constant (cooling without changing me).** - Moist air enters at 3 kg/s. at 10oC 80% RH. heated exit at 30oC. - (PV) = 0.01228 bar. - (0.622) × 0.009824 = 0.00617 kg/Kg dry air. - (0.8) × 0.01228 = 0.009824 bar. - H1 = [283.1 + (1) (254.8)×(8) ] / [ 303.2 + 0.00617 (2556.3) ] = 895.95kW. - H2 = 956.91k00. - Heat added = 60.967 kW ### **Humidity Rate = (mw/ma) Cooling = dehumidifying (usually).** ### **Aspergillus Oryzae = Koji** - Mw = 20 - H20 = 18 - Amino acid = 30 - Peptide = (30+20) - (H20 ) = (32). ### **Pectin is a structural polysaccharide. Starch is a storage polysaccharide.** ### **Murin content in gram (tre) bacteria = 70% (Peptidoglycan).** ### **Diameter of mycoplasma = 0.05-0.3 μm.** ### **Diameter of fimbriae 3 - 10 nm** - Found in gram +ve bacteria - hair like appendages ### **Toxin in groundnut kernel = Aflatoxin.** ### **Psychrophiles** - (-20 - 20 °C) - Optimum (R) as low as 0oC ### **Thermophilus** - (40 - 50 °C) - Optimum (80-60 °C) ### **(t) (g) (6/8) = (3.3)10g (1.07/105) (109) x (5) Integration = (generation time) (t) = 19 min.** ### **Aerobic colony count (SPC)** - Aerobic plate count / Standard plate count. - total viable count (TVC) ### **Non carbonated coins = still coins.** ### **Gram staining = Differential staining** ### **Rhizopus = Tempeh starter** ### **Gurm = heat substitute** ### **Yeast and mold determination = potato glucose agar** ### **Fat rich foods most stable at (0.13 - 0.9 aW).** ### **Water activity of distilled water = (1-0)** ### **Stachybotrys chartarum = black mold.** ### **Psychotrophic** - gum (-ve) - Acineto backer ### **Cell membrane** - Separates interior of all cell walls from outside environment. ### **Cell wall** - Shape to the cell. ### **Gram (+ve) bacteria = Cytoplasmic lipid membrane** ### **Oligotroph:** - Low nutrient availability ### **Osmophile:** - High conc. of (Sugar/salt) (0.6-0.85) ### **Xenophile:** - Dry conditions (aw < 0.8) (<0.6) some cases. ### **Thermal death time =** Time taken to kill specific bacteria at specific temperature. ### **F= (TDT) X 10T-To = Thermal death time. (121.1oC)** ### **Percentage of acetic acid in vinegar = 5-20%.** ### **Sauerkraut contains Lutein & Zeaxanthin.** ### **Traditional Korean sausage = Sundae.** ### **DNA = first product human use (Rennin)** ### **Ropines in wine = Leuconostoc mesenteroide.** ### **Rum = distilled liquor.** ### **Barley flavor is influenced by both adjuncts and malt.** ### **Hops** - Bitterness and aroma - Antimicrobial ### **Blue cheese starters (Lactis)** - *P. roqueforti)* ### **Soy Sauce** - Aspergillus oryzae - Aspergillus sojae ### **Common inoculum for pickle and sauerkraut = *L. plantarum*.** ### **Grape Juice Fermentation** - *Candida picha* - *S. cerevisiae* ### **Hepatitis A = Food Borne** - Blood/semen. ### **Most spoilage bacteria grow at neutral pH (5-8).** ### **Salmonellosis = food infection** ### **Chilled shrimp spoilage = Achromobacter** - (Salmonella - live (Gram +ve)) ### **Folder method of pasteurization** - Temp = 62.5oC - Time = 30 min ### **Z value = 10oT or D value = 10-fold down (1 log cycle).** ### **Indicator bacteria for milk pasteurization** - *Coxiella burnetii* ### **Belt speed for grain transport = (2.5-2.8 m/s)** ### **Sporogenes more heat resistance than Clost. (A) type.** - *Stearo thermophilus* > *C. Sporogenes* > *C.BA* > *B. coagulans* ### **HTST also called flash pasteurization (72°c [155°F]). Target milk (Coxiella burnetti) 30s.** ### **Blanching is used for: ** - Both vegetables and meat - (mostly for vegetables) ### **[Milk is added in water (H2O). Butter is water in oil (BW).** ### **The vast majority of plasticizers = Estors of thalic acid.** ### **F0 value = when ≥ 121.1oC** - Heat to preserve. - Acidity - Salt and sugar ### **Common hurdles used in food preservation** - Bactos - 155oC - (Standard) - Coxiella burnetti flash pasteurization ### **Heat treatment used to inactivate = fruit juices** - pectin methyl esterase - Polygalacturonase - α amylase X - β amylase X ### **Earthy flavor = Spoiled meat = Actinomycetes** ### **Egg yolk = Emulsifier = depends on lecithin content.** ### **Fermented fish product = Bagoong** ### **Nitrates in meat prevent = botulinum spore germination.** ### **Clostridium = usually all from G(TUI).** ### **Bacon = pork belly = (Ham = legs). Cured meat.** ### **Quality of eggs judged by candling.** ### **Parboiled rice also known as converted rice.** ### **Rice bran oil = rich in γ-oryzanol** - Hull, Bran, Germ. ### **Milling of rice removes endosperm intact.** ### **Parboiling leads to loss of antioxidants.** ### **Salt used in bread making =** - An antioxidant. - Heightening gluten structure. - Dough strength. ### **Durum/wheat → pasta wheat = yellow endosperm. Milled → endosperm ground → semolina** - (Pasta color) ### **Glutenin = dough elasticity. Gliadin = bread rising** ### **Wheat kernel =** - Endosperm - Bran - Germ - Husks removed earlier. ### **Density of butter = (911 g/L)** ### **% of PUFA in butter = (3%)** ### **Max moisture in whole milk powder = (4-6%)** ### **Whipping quality = foam production.** ### **Neutralizen in butter = NaHCO3 (Ca(OH)2)** ### **Eyes in swiss cheese = Propionibacterium** ### **White pepper (color) = matured berries.** ### **Astringency in tea = poly phenols.** ### **Selected coconut = alkaline compound (elevated temp)** - Dutch processing ### **Conching =** - Intense mixing/kneading - Viscosity of chocolate (fats adjusted with addition of fats like cocoa butter/emulsifiers = Standardization. ### **Crystal form** - α crystals (1) = low melting point - smooth texture. - β crystals (II) = moderate to low - coarse texture - less desirable. - β crystals (III) = larger more stable - coarse texture - Mixed crystals = both α and β form characteristics - γ crystals = Less common in food. - δ crystals = very high melting points. ### **White tea = wilted un-oxidized** ### **Green tea = un-wilted un-oxidized** ### **Black tea = wilted fully oxidized** ### **Cardamom =** - α-terpencol - limonene - menthone ### **Decaffeination of coffee =** - Super critical CO2 - Dichloromethane - Ethyl acetate. ### **Product of enzymatic browning = quinones (PPO causes it)** ### **Pectin** - Apples (citrus fruits - high amt of pectin). - Contains = galacturonic acid. - Pectin reduces syneresis. ### **Redness in apple = Anthocyanin.** ### **Fruit squash = PFA limit for fruit juice = 12.5 %** ### **FSSAI logo for fortified soy with (FT)** ### **Emulsifier preservative (E200-249) Emulsifiers/stabilizers etc (E 400-499)** ### **Cop = Jhald (Refrigeration?) Cold = Hot-tool** - Heat absorbed or rejected. - work done ### **Directly from temp (Ideal) = (Bideal) / (Breal) = Hardening of fats** ### **Refrigeration =** - Decomposition of colloidal system. - Fsc = cooling ### **MCP = (30+5) + (m)** - Cooling - Heat out - Condensation - Evaporation. - Working - Heating ### **EA = - (T2-T1) / 2.303R (T1T2)** - 2nk = lnA - (EA/RT1). - -δ = lnA - (EA/RT1) - -9 = lnA - (EA/RT2) - 1 = (EA/R) ( T2-T1/ T1T2) - 1 = (EA/8.314 J/mol) ( 2 X 153 - 1 X 163 / 8.314 X 153) ### ** (T1 / T2). ## Rate of change of a biological or chemical process with 10e Change in temp** ### **Probability of spoilage = (Y0)** - If given, directly = (Ton)-1 = (1/Ton) - If given, 10h-1 = (ton)-1= (1/107). - (0.8)(10-x)(10-x)(-20)(1-10-x)/ (10-x)(1-10-x)(2(10-x) = ff / (ff2 / 02 ) ### **Separation factor =** - √(x2 + 1). ### **Efficiency of centrifugal separator = (Centrifugal force/Gravity force).** ### **g = [V2 / (r)] = (2/g) (ω2 x r) - V = [(2/g) ( ω2 x r) x (ρs - ρl) r] / [ μ ] = (ω2 D2 L2 ) / (ω2. D2 . L2 + (2/g) ( ω2 x r) x (ρs - ρl) r + μ] ### **During falling rate period, when falling rate > constant rate, the moisture content reduces.** - Surface = Free moisture. - Second falling rate = interstitial water. - Falling rate = Free water. ### **Microwave drying = dielectric drying.** ### **qw = (ERH) = 65 = (0.65) / 100.** - 100 ### **500 x 0.8 = 400 kg/hr (remind) = (P)(0.4)** - (1)x 0.5 - 100 = (100+x) = P - (100)(0.5) + 2 x 0.01 = (P)(0.4) - 50 + 0.1x = 40 +0.4x - 10 = 0.3x - x = 33.33 - Total P= (100+ 33.33) = 133.33 kg/hr - (2)(0.4) - (0.5) - 500 → 61 → 52 → (y)(0.1) - Evaporator (2 Stages) ### **Rehydration Ratio = (Rehydrated) / (wd) 75 = (6:1)** - 15 ### **Ф = 1 Strue 0.9 = 1 - Phulk. Strue** ### **Ev spherical diameter = 4/3πdL3 de3 = (4/3π)dL de2 = [(4/3π)dL)1/3** ### **Sphoricity of grain = p = (lxbxh)1/3 / de** ### **Porosity (ε) = [Vv / Vs]. ### **de = side3 = de = (x) P=6(As / Ap) = (6 / πα2) (πd2 / 6) = (d/2a).** ### **Φwv = (1/Σmi ) = mass fraction** ### **Shear-thinning common for liquids but may occur in solids.** ### **Velocity of falling film = V = (ρgδ2 / (2μ)) (g2 - S2) - Vavg = (1/δ) ∫ (ρgδ2/ (2μ)) (g2 - S2) dδ = (1/δ) (ρgδ2 / (2μ)) ∫ (g2 - S2) dδ = (1/δ)(ρgδ2/(2μ))[ (g2 δ ) - (S2δ / 3) ] = [ ( ρg / 2μ ) (δ2/3) ] ### **Time to fill the tank = (Food Eng) Volume = (πd2h) Av = (g) t = (V / Av)** - (no formula needed) - Ignore viscosity data. - (Ma = T / (du / day) - Ma = (M) (du / day) - n = 0.4 - n - 1 = (0.6) - T = (25)(4) - Ma = (2.5)4-0.6 - 1.05 / 2.5 = 0.42 - 4 = (h)(g) = 9.0. - 2.5 / 1.05 = (9.0)(2) - 4 = 4.245 ### **Turbulent flow fanning friction AP = [(g/√g) (v2 / D)]0.25= [(0.079) (Re)-0.25]** - AP = (4 fL v2/ 2Dg) - Not laminar. ### **L2/(1-ε^2) = [ total v / Void v = Total v - Void v ]** - L1/ (1 - ε1) = more filled = Void fraction - ε = (1-X) / (1-0.7) = ε ### **Rheotropic = α↓ with time (with constant conditions).** ### **Thixotropic = α↑ with time.** - The same as dilatant. ### **Fourier's law of conduction = Q= (KA / Δx) dT** ### **Heat flow through a cylinder = Q = (2πL)KAT / ln(r2/r1)** ### **Nu number = (2 conduction / (conduction + convection)) = (2hL/K) / (2hL/K + 2πL/K)** ### **In series: (18-(-18) 21+12+13 K1A1 K2A2 K3A3 Thermal resistance** - Q = (ΔT / [(1 / K1A1) + (1 / K2A2) + (1 / K3A3)]) = (Q / (1 / K1)) = (Q * K1) = (ΔT / A/h1/K1 ) - Q = (Q/ (1 / K2)) = (Q* K2 ) = (ΔT / (A/h2)/K2 - Q = (Q/ (1 KK3)) = (Q* K3) = (ΔT/ (A/h3)/ K3) ### **Bi = [ (hL / K) / (1) ] = (hL/k). ** ### **R = (Q / (ΔT)) = (1 / K1) + (1 / K2) = ((2πrL) / K1 ln(r2/r1) + (2πrL) / K2 ln(r2/r1) ) ** - Q = (ΔT(K1ln(r2/r1) / (2πrL)) + ( ΔT(K2ln(r2/r1)) / (2πrL) )). - Q = ( ΔT / [( 2πrL / K1ln(r2/r1)). + (2πrL / K2ln(r2/r1)) ] - R = ( ΔT / (K1ln(r2/r1) / (2πrL) + K2ln(r2/r1) / (2πrL) ) = ( ΔT / [1/ 2πrL ( (K1ln(r2/r1) + K2ln(r2/r1) )] ) - K1 and K2 are heat transfer coefficients. ### **ff = Fouling factor, Ud = 2.22 x 10-4 Ud = Uc x e=0.015 = (900) W/m2.K Therefore, of = 2.22 x 10-4 = (1500) W/m2.K. ** ### **Uf = Heat transfer coeft under fouling condition (W/m2.K) ΔT1 = ΔT2 LMTD = ΔT1 - ΔT2. UA(ΔT) = (m) CpΔT ΔT1 + ΔT2 Fluid which is of constant not counter current 2 (m) (Cp) (200kJ/s) (LMTD) = (600) J/sm Counter flow/co-flow mentioned = LMTD needed (4.14 - 1) #### **Find LMTD Thi = 10 Tci = 12 The = 22 Tce = 85** - [ (10-85) - (22-12) ] / ln [ (10 -85) / (22-12) ] = 22.32 oK ### **Peclet No. = Convective transport / Diffusive transport** - Bird Peck - (time) Related - Oscillate = LU - (time) - LU / D ### **Sherwood number = (km) L / D = convective mass transfer. Dittorre = (time)** ### **(Le) = law's no: [(α / D) / (ν /D)]1/2** ### **Log mean pressure value if vapor pressure = Pi** - PB1= Patm - Pi - PB2= Patm - P0 - ΔPm = (PB1 - PB2) / ln(PB1 / PB2) ### **Sherwood number in mass transfer = Nussdt no. in heat transfer** ### **Degree of homogeneity depends on mixing time in a mixing/stirred tank** ### **Reynolds no. = Forced convection. ** - As porosity increases thermal conductivity decreases. ### **Granshof no. = Free convection** ### **Most bioprocessing fluids = pseudoplastic** ### **Gate 2016 (Missed) (Triple effect evaporator)** - (N) = [U1AT1 ∪2AT2 + U3AT3] - ΔT = ΣΔT = (ΔT1 + ΔT2 + ΔT3) = (TS - T1) - = (ΣΔT) / [ (Y(U1) / (Y(U1) + (Y(U2) + (Y(U3))) = (121-65) X (2760) / (2760) + (11875) + (11250) = 108.80

Gate XE Notes (Food Eng) PDF

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