CENEVAL EGEL Plus Ingeniería en Alimentos (EGEL Plus IALI)

A single-effect falling film evaporator is fed with 1,000 kg/h of clarified tomato juice containing 5.0% total soluble solids by mass. The product stream leaving the evaporator is concentrated to 30.0% total solids. Operating under steady-state conditions with no solids loss in the vapor, what is the rate of water evaporated (W) from the juice?

• A166.7 kg/h
• B833.3 kg/h
• C500.0 kg/h
• D950.0 kg/h

A freeze-concentration unit receives 500 kg/h of clarified apple juice containing 12.0 °Brix (12.0% dissolved solids). The crystallization system separates pure ice crystals, discharging a concentrated juice stream containing 48.0 °Brix. Assuming steady-state operation and zero solute entrapment in the ice wash column, what is the discharge rate of concentrated juice (P)?

• A60 kg/h
• B375 kg/h
• C125 kg/h
• D250 kg/h

In thermal bacteriology and food preservation kinetics, what is the fundamental definition of the decimal reduction time (D-value)?

• AThe heating time required at a specific constant temperature to destroy 90% of a microbia…
• BThe temperature increase required to reduce the thermal death time of a target microorgan…
• CThe total equivalent minutes at 121.1 °C required to deliver a commercial sterilization p…
• DThe time needed at any processing temperature to reduce the surviving bacterial spore cou…

A canned low-acid vegetable product contains an initial population of 1.0 × 10⁴ spores of Clostridium botulinum per can. The commercial process targets a 12-decimal reduction (12D process), reducing the contamination risk to 1.0 × 10⁻⁸ spores per container. If D121.1 °C for C. botulinum spores is 0.21 minutes, what is the required thermal lethality value (F0)?

• A0.84 minutes
• B1.68 minutes
• C12.00 minutes
• D2.52 minutes

During a thermal death time study on Geobacillus stearothermophilus spores, the decimal reduction time is measured as D105 °C = 50.0 minutes and D115 °C = 5.0 minutes. What is the z-value for these bacterial spores?

• A5.0 °C
• B10.0 °C
• C15.0 °C
• D20.0 °C

A continuous plate pasteurizer heats 2,000 kg/h of whole fluid milk (specific heat capacity Cp = 3.90 kJ/kg·°C) from an inlet temperature of 4.0 °C to a pasteurization holding temperature of 72.0 °C. What is the required rate of thermal heat transfer (Q) supplied to the milk in this heating section?

• A73.7 kW (265,200 kJ/h)
• B294.7 kW (1,060,800 kJ/h)
• C147.3 kW (530,400 kJ/h)
• D530.4 kW (1,909,440 kJ/h)

A counter-current shell-and-tube heat exchanger cools refined vegetable oil from 120.0 °C to 50.0 °C using chilled water that enters at 15.0 °C and exits at 35.0 °C. What is the Logarithmic Mean Temperature Difference (LMTD) for this heat exchanger configuration?

• A56.4 °C
• B60.0 °C
• C46.3 °C
• D70.0 °C

During continuous thermal processing of dairy products in a plate heat exchanger, denaturation of whey proteins and mineral precipitation form an insoluble layer (milk stone fouling) on the heat transfer plates. How does this fouling layer impact the overall heat transfer coefficient (U) and the pressure drop (ΔP) across the plates?

• AU increases due to increased surface roughness, while ΔP remains unchanged
• BU remains constant because plate geometry is fixed, while ΔP decreases
• CU decreases, but ΔP also decreases due to laminar boundary layer dampening
• DU decreases due to added conductive thermal resistance, while ΔP increases due to channel…

Plank's equation estimates the freezing time (tf) of an infinite slab of food as tf = [ρ·ΔHf / (Tf - T_inf)] · [P·a / h + R·a² / k], where 'a' is slab thickness, 'h' is surface convective heat transfer coefficient, and 'k' is thermal conductivity of the frozen layer. If the slab thickness 'a' is doubled (2a) while all other thermal properties and boundary conditions remain unchanged, how does the internal conductive resistance term (R·a² / k) change?

• AIt doubles (increases by a factor of 2)
• BIt quadruples (increases by a factor of 4)
• CIt increases eightfold (increases by a factor of 8)
• DIt remains constant because shape factor R is invariant

In convective hot-air tray drying of mango slices, ambient air at 25.0 °C and 60% relative humidity is passed across an indirect steam heater coil before entering the drying chamber. If sensible heat is added without adding or removing moisture vapor, how do the dry-bulb temperature, relative humidity, and absolute humidity (humidity ratio) of the air change?

• ADry-bulb temperature increases, relative humidity increases, and absolute humidity increa…
• BDry-bulb temperature increases, relative humidity remains constant, and absolute humidity…
• CDry-bulb temperature increases, relative humidity decreases, and absolute humidity remain…
• DDry-bulb temperature decreases, relative humidity decreases, and absolute humidity remain…

During the convective dehydration of high-moisture biological tissues, what physical mechanism characterizes the constant-rate drying period?

• AEvaporation of unbound surface water where the food surface remains saturated and stays a…
• BInternal liquid capillary diffusion where moisture transport to the surface is the rate-l…
• CSublimation of bound water monolayers governed by internal molecular Knudsen diffusion
• DRapid crust formation where vapor pressure within the food core exceeds atmospheric press…

In the industrial spray drying of fruit juices and honey solutions rich in low-molecular-weight sugars (fructose and glucose), severe chamber wall deposition and powder stickiness often occur. What is the fundamental thermodynamic and material science cause of this phenomenon?

• AThermal degradation of cellulose microfibrils creating high surface electrostatic charges
• BPrecipitation of insoluble calcium pectate salts onto stainless steel cyclone walls
• CInadequate droplet atomization producing excessively large particles that exceed terminal…
• DThe drying particle temperature exceeds the glass transition temperature (Tg) of the amor…

A fluid food exhibits no initial yield stress, and its apparent viscosity decreases continuously as the applied shear rate increases. Which rheological model and flow behavior index (n) describe this material?

• APseudoplastic (shear-thinning) fluid conforming to the Ostwald-de Waele power law with n…
• BDilatant (shear-thickening) fluid conforming to the Ostwald-de Waele power law with n > 1
• CBingham plastic fluid with a positive yield stress (τ0 > 0) and constant plastic viscosity
• DNewtonian fluid conforming to Newton's law of viscosity with flow behavior index n = 1

A mango purée behaves as an Ostwald-de Waele power-law fluid with a consistency index K = 12.0 Pa·sⁿ and a flow behavior index n = 0.40. What is the apparent viscosity (η_app) of this purée when flowing through a pipe section under a wall shear rate of γ̇ = 100 s⁻¹?

• A12.00 Pa·s
• B0.12 Pa·s
• C0.76 Pa·s
• D3.02 Pa·s

In continuous centrifugal milk skimming, Stokes' law describes the terminal settling velocity of fat globules: v = [d²·(ρ_p - ρ_f)·a] / (18·μ). In a disc-stack centrifuge rotating at high angular velocity ω, what physical parameter replaces gravitational acceleration (g) to achieve rapid phase separation?

• AViscous shear stress τ = μ·(dv/dr)
• BCentrifugal acceleration a = r·ω², generating an acceleration thousands of times greater…
• CHydrostatic buoyant pressure gradient dP/dz = ρ·g
• DReynolds turbulence kinetic energy factor k = 0.5·(u'² + v'² + w'²)

Arrange the four primary pressure-driven membrane separation processes in order of DECREASING pore size (from largest membrane pores to densest non-porous membranes):

• AReverse Osmosis > Nanofiltration > Ultrafiltration > Microfiltration
• BUltrafiltration > Microfiltration > Reverse Osmosis > Nanofiltration
• CNanofiltration > Ultrafiltration > Microfiltration > Reverse Osmosis
• DMicrofiltration > Ultrafiltration > Nanofiltration > Reverse Osmosis

A batch steam-jacketed kettle is used to heat 500 kg of liquid vegetable puree (specific heat capacity Cp = 4.00 kJ/kg·°C) from 20.0 °C to 90.0 °C. The heating is supplied by condensing saturated dry steam at 120.0 °C (latent heat of vaporization λ = 2,202 kJ/kg). Assuming complete insulation with zero thermal heat losses to the surroundings, how much steam must condense?

• A31.8 kg
• B63.6 kg
• C140.0 kg
• D0.064 kg

In continuous HTST milk pasteurization (minimum 72.0 °C for 15.0 seconds), why must the minimum physical length of the holding tube be sized according to the velocity of the fastest-moving fluid particle (v_max) rather than the average bulk velocity (v_avg)?

• ABecause food safety regulations mandate that every volume element receives at least the m…
• BBecause turbulent friction factors at the pipe wall slow down thermal conduction into the…
• CBecause flow diversion valves can only actuate if the centerline velocity matches the pum…
• DBecause milk fat globules migrate exclusively along the tube perimeter where velocity is…

Why is supercritical carbon dioxide (scCO2) widely preferred over conventional organic solvents (such as hexane or methylene chloride) for commercial decaffeination of coffee beans and extraction of hop bitter acids?

• AIt operates at extremely high temperatures (> 250 °C) that simultaneously sterilize the r…
• BIt forms permanent covalent adducts with bitter polyphenols, stabilizing aroma compounds…
• CIt has near-ambient critical conditions (Tc = 31.1 °C, Pc = 7.38 MPa), leaves zero toxic…
• DIt is a highly polar solvent that selectively extracts water-soluble ionic minerals while…

In the manufacture of expanded ready-to-eat breakfast cereals and puffed snacks using high-shear extrusion cooking, what physical phenomenon directly drives the sudden radial expansion of the melt at the die exit?

• AThermal expansion of entrapped air bubbles according to Charles's ideal gas law
• BDecomposition of added sodium bicarbonate into carbon dioxide gas due to mechanical shear
• CMelting of lipid fractions that form a low-viscosity continuous phase at atmospheric pres…
• DInstantaneous flash-vaporization of superheated liquid water into steam as the melt exper…

When freezing fresh beef muscle, why does slow freezing (e.g., in a static cold room at -18 °C) cause significantly greater drip loss upon thawing compared to rapid cryogenic freezing (e.g., liquid nitrogen immersion)?

• ASlow freezing denatures myosin heads through rapid intracellular ice crystal propagation
• BSlow freezing forms few, large extracellular ice crystals that puncture cell membranes an…
• CSlow freezing causes surface freeze-burning that accelerates lipid rancidity throughout t…
• DFast freezing prevents ice nucleation entirely, maintaining tissue water in an amorphous…

Skim milk at 20.0 °C (density ρ = 1,030 kg/m³, dynamic viscosity μ = 0.0020 Pa·s) is pumped through a sanitary stainless steel pipe with an internal diameter D = 0.050 m at a mean velocity v = 1.20 m/s. What is the Reynolds number (Re) and the corresponding flow regime?

• ARe = 30,900; fully turbulent flow
• BRe = 30.9; laminar flow
• CRe = 3,090; transitional flow
• DRe = 61,800; fully turbulent flow

In freeze drying (lyophilization) of pharmaceutical proteins and high-value food ingredients, water is removed by sublimation from the frozen state. To maintain sublimation without melting the ice core, what thermodynamic condition must the chamber pressure and product temperature satisfy?

• AAbove the critical point of water (374.0 °C and 22.06 MPa)
• BAt atmospheric pressure (101.3 kPa) with dry air below -40 °C
• CStrictly below the invariant triple point of water (0.01 °C and 611.7 Pa / 4.58 mmHg)
• DBetween the freezing point (0 °C) and boiling point (100 °C) at 10.0 kPa

When sizing the commercial refrigeration capacity for a cold storage warehouse designed for fresh apples held at 1.0 °C, what thermal heat source must be incorporated into the refrigeration load that is completely absent when storing frozen packaged beef?

• ALatent heat of fusion from cyclical water freezing
• BSensible heat of moisture condensation on air handler coils
• CConductive heat transmission through floor insulation slabs
• DVital heat of respiration generated by ongoing aerobic metabolism of living botanical tis…

High Hydrostatic Pressure processing (HPP, 400 to 600 MPa at 20 °C) achieves microbial vegetative pathogen inactivation in avocado guacamole without degrading natural green color, fresh flavor, or ascorbic acid. What fundamental chemical principle explains this selective inactivation?

• AHPP selectively destroys covalent C-C and C-H bonds while reinforcing quaternary protein…
• BHPP disrupts weak non-covalent interactions (hydrogen bonds, hydrophobic, and ionic bonds…
• CHPP induces free radical sonoluminescence that destroys microbial DNA without reacting wi…
• DHPP operates by sudden cavitation bubble implosions that physically shear bacterial flage…

Under the Mexican front-of-pack nutritional labeling standard NOM-051-SCFI/SSA1-2010 (and its amendments), what is the energy threshold for applying the mandatory black octagonal warning seal 'EXCESO CALORÍAS' on solid prepackaged foods containing added sugars, fats, or sodium?

• ATotal energy content ≥ 275 kcal per 100 g of solid product
• BTotal energy content ≥ 400 kcal per serving size
• CTotal energy content ≥ 150 kcal per 100 g of solid product
• DTotal calories exceeding 20% of the recommended daily intake per package

A beverage development team formulates a zero-calorie carbonated soft drink (no added sugars) containing added sodium citrate and sucralose. Under NOM-051-SCFI/SSA1-2010, what specific warning seal and rectangular cautionary legend are triggered if the beverage contains 60 mg sodium per 100 mL and uses sucralose as a non-caloric sweetener?

• ASeal 'EXCESO AZÚCARES' and legend 'PRODUCTO NATURAL SIN CONSERVADORES'
• BSeal 'EXCESO GRASAS TRANS' and legend 'CONTIENE CAFEÍNA, EVITAR EN NIÑOS'
• CSeal 'EXCESO SODIO' (threshold ≥ 45 mg/100 mL in calorie-free beverages) and legend 'CONT…
• DNo warning seals or legends are required because non-caloric sweeteners are exempt from N…

In sensory evaluation, a food engineer conducts a Triangle Test to determine if changing an emulsifier in mayonnaise creates a detectable sensory difference. In this forced-choice discriminative test, what is the theoretical probability (p) of an assessor identifying the odd sample purely by chance guessing?

• Ap = 0.50 (50.0%)
• Bp = 0.33 (33.3%)
• Cp = 0.25 (25.0%)
• Dp = 0.10 (10.0%)

How does the sample presentation protocol and chance guessing probability of a Duo-Trio sensory test differ from that of a standard Triangle Test?

• AIn duo-trio, panelists evaluate four samples with p = 0.25, whereas triangle evaluates th…
• BIn duo-trio, samples are presented in pairs with p = 0.33, whereas triangle presents thre…
• CIn duo-trio, panelists evaluate samples sequentially with no reference sample, giving p =…
• DIn duo-trio, panelists receive an identified Reference sample (R) followed by two coded s…

Which methodological feature is fundamental to Quantitative Descriptive Analysis (QDA) when profiling the sensory characteristics of a new plant-based beverage?

• ATrained panelists develop a consensus vocabulary of descriptive terms using physical refe…
• BUntrained consumers evaluate product liking on a 9-point hedonic scale in an open focus g…
• CA single expert master taster assigns numerical scores to defect categories according to…
• DChemical gas chromatography headspace peak areas are directly substituted for human panel…

When assessing consumer acceptability of a newly reformulated strawberry yogurt with reduced sugar, which sensory testing protocol and panelist selection are most scientifically appropriate?

• AA trained descriptive panel of 8 judges using a 15-cm line scale for overall liking
• BA triangle discriminative test administered to 15 food science professors
• CA 9-point hedonic scale administered to a cohort of 60 to 100 regular consumers of strawb…
• DA ranking test for sweetness intensity conducted by 5 plant maintenance operators

In formulating Intermediate Moisture Foods (IMF, target water activity aw between 0.65 and 0.85) such as confectionery fillings and soft-baked snack bars, why is glycerol (glycerin, molecular weight = 92.1 g/mol) significantly more effective at lowering water activity than sucrose (molecular weight = 342.3 g/mol) on an equal mass basis?

• AGlycerol acts as a chemical surfactant that volatilizes water into the packaging headspace
• BAccording to Raoult's law, water activity depression depends on the mole fraction of solu…
• CGlycerol forms an insoluble crystalline matrix that physically encapsulates moisture mole…
• DGlycerol lowers the solution pH below 4.0, which chemically ionizes free water molecules

In an aseptically packaged orange juice held at 25.0 °C, the oxidative loss of ascorbic acid (vitamin C) follows first-order reaction kinetics: ln(C/C0) = -k·t. If the reaction rate constant is k = 0.0231 day⁻¹, what is the half-life (t1/2) of vitamin C in the juice?

• A13.0 days
• B43.3 days
• C21.6 days
• D30.0 days

An Accelerated Shelf-Life Testing (ASLT) study is conducted on a dehydrated extruded snack. The primary deteriorative reaction (lipid autoxidation) exhibits a temperature quotient Q10 = 2.0. If the product maintains acceptable sensory crispness and oxidation limits for 15.0 days when stored at an elevated test temperature of 45.0 °C, what is its predicted shelf life when stored under ambient conditions at 25.0 °C?

• A60.0 days
• B30.0 days
• C120.0 days
• D7.5 days

Which combination of food hydrocolloids exhibits strong macromolecular synergism, where neither polysaccharide forms a gel on its own at room temperature, but combining them produces a firm, elastic, thermoreversible gel?

• AGum arabic and carboxymethylcellulose (CMC)
• BHigh-methoxyl pectin and gelatin
• CXanthan gum and locust bean gum (carob gum)
• DCornstarch and sodium alginate

In formulating a stable water-in-oil (W/O) table margarine where vegetable oil forms the continuous phase and aqueous droplets form the dispersed phase, which range on Griffin's Hydrophilic-Lipophilic Balance (HLB) scale must the primary emulsifier possess?

• AHLB 8.0 to 12.0 (oil-in-water O/W emulsifiers)
• BHLB 3.0 to 6.0 (lipophilic water-in-oil W/O emulsifiers)
• CHLB 13.0 to 16.0 (detergent and solubilizing agents)
• DHLB 16.0 to 20.0 (hydrophilic hydrotropes)

In commercial Modified Atmosphere Packaging (MAP) of fresh retail beef steaks, what specific binary gas mixture is widely utilized to simultaneously promote a bright cherry-red color and retard spoilage?

• A100% Carbon Monoxide (CO) to permanently fix carboxyhemoglobin
• B95% Nitrogen (N2) and 5% Carbon Dioxide (CO2) to eliminate all aerobic processes
• C50% Ethylene and 50% Argon to accelerate enzymatic post-mortem proteolysis
• D70% to 80% Oxygen (O2) and 20% to 30% Carbon Dioxide (CO2)

When selecting flexible barrier packaging materials for fried potato chips containing 35% polyunsaturated vegetable oil, what combination of barrier transport properties is essential to prevent stale texture and rancidity?

• AExtremely low Water Vapor Transmission Rate (WVTR) to prevent moisture sorption and loss…
• BHigh Oxygen Transmission Rate (OTR) to allow respiration, coupled with high WVTR to allow…
• CHigh CO2 permeability to prevent package swelling, coupled with zero puncture resistance
• DHigh UV transmission to allow natural antimicrobial sterilization of the chip surfaces

In the formulation of functional foods, what is the fundamental scientific distinction between prebiotic and probiotic ingredients?

• APrebiotics are live bacterial cells, whereas probiotics are dead microbial cell wall extr…
• BPrebiotics are mineral catalysts, whereas probiotics are vitamin cofactors synthesized by…
• CPrebiotics are non-digestible food ingredients (such as inulin and oligofructose) that se…
• DPrebiotics function exclusively in the stomach at pH 2.0, whereas probiotics function exc…

In reformulated cooked meat sausages designed to meet reduced-sodium targets, simply cutting sodium chloride (NaCl) content by 50% causes soft mushy texture, high purge cooking losses, and bland flavor. What technical formulation strategy compensates for these functional defects?

• AReplacing all NaCl with calcium chloride (CaCl2) and adding high-fructose corn syrup
• BPartial replacement of NaCl with potassium chloride (KCl) blended with yeast extract to m…
• CAdding high levels of native wheat starch and reducing thermal cooking temperatures below…
• DReplacing water with liquid vegetable oil and eliminating all curing salts

In food packaging material interactions, what is the technical distinction between chemical migration and flavor scalping?

• AMigration occurs only through glass containers, whereas scalping occurs only in aluminum…
• BMigration refers to microbial penetration through pinholes, whereas scalping refers to mo…
• CMigration is the absorption of grease into cardboard, whereas scalping is the oxidation o…
• DMigration is the diffusion of packaging substances (plasticizers, monomers, additives) in…

When reformulating a traditional premium ice cream to create a 'no added sugar' version using high-intensity sucralose, why is it necessary to incorporate bulking agents and sugar alcohols (polyols like maltitol or erythritol)?

• ATo provide colligative freezing point depression, total solids, and scoopable texture tha…
• BTo chemically hydrolyze milk proteins into hydrophobic peptides
• CTo increase the freezing point of the mix to +4.0 °C to prevent ice crystallization
• DTo act as primary emulsifiers that permanently eliminate the need for dairy milkfat

How does an active packaging system differ fundamentally from an intelligent packaging system in food quality preservation?

• AActive packaging monitors product temperature, whereas intelligent packaging releases tox…
• BActive packaging operates only on glass bottles, whereas intelligent packaging operates o…
• CActive packaging directly intervenes by releasing or absorbing substances (e.g., oxygen s…
• DActive packaging is designed exclusively for dry pet foods, whereas intelligent packaging…

In an oil-in-water (O/W) food emulsion such as a dairy-free coffee creamer, the upward gravitational separation of oil droplets (creaming velocity, v) is governed by Stokes' law: v = [2·r²·(ρ_oil - ρ_serum)·g] / (9·η_continuous). Based on this relationship, which industrial processing and formulation changes will most effectively minimize the creaming velocity?

• AIncreasing oil droplet radius 'r' via slow paddle mixing while decreasing continuous phas…
• BDecreasing droplet radius 'r' via high-pressure two-stage homogenization (since velocity…
• CHeating the emulsion to 95 °C to decrease serum viscosity and boiling out dissolved air
• DDiluting the emulsion with distilled water to maximize density difference (ρ_oil - ρ_seru…

In the Stage-Gate product development framework applied to commercial food innovation, what is the primary business and technical function of Gate 3 ('Go to Development')?

• AConducting exploratory brainstorm sessions to generate unconstrained product concepts
• BAuthorizing the final nationwide supermarket launch and marketing advertising spend
• CAuditing consumer warranty claims six months after product commercialization
• DEvaluating preliminary benchtop proof-of-concept, business case feasibility, and sensory…

What is the correct sequential order of the seven foundational principles of the Hazard Analysis Critical Control Point (HACCP / APPCC) system as defined by the Codex Alimentarius Commission?

• A1. Hazard Analysis; 2. Determine CCPs; 3. Establish Critical Limits; 4. Establish Monitor…
• B1. Establish Critical Limits; 2. Hazard Analysis; 3. Determine CCPs; 4. Establish Monitor…
• C1. Determine CCPs; 2. Establish Monitoring; 3. Hazard Analysis; 4. Establish Critical Lim…
• D1. Good Manufacturing Practices; 2. Hazard Analysis; 3. Determine CCPs; 4. Establish Corr…

A 10 g sample of fresh cheese is blended with 90 mL of sterile diluent (10⁻¹ dilution) and then serially diluted in tenfold steps. Duplicate pour plates of plate count agar, each inoculated with 1 mL of the 10⁻³ dilution, give 152 and 168 colonies after incubation; the plates from the other dilutions are outside the countable range. What aerobic mesophilic count should be reported?

• A1.6 × 10⁵ CFU/g
• B3.2 × 10⁵ CFU/g
• C1.6 × 10² CFU/g
• D1.6 × 10⁶ CFU/g