Agricultural/Bioengineering: Food Engineering Flashcards
7 cards from real Agricultural/Bioengineering practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Agricultural/Bioengineering: Food Engineering flashcards as text
Which heat transfer mechanism is primarily responsible for cooking food in a microwave oven?
Answer: Dielectric heating
Microwaves cause polar molecules like water to rotate rapidly, generating heat internally through dielectric heating.
The 'z-value' in thermal processing refers to:
Answer: The temperature increase needed to reduce D-value to 1/10th
The z-value is the temperature change required to achieve a 10-fold (one log) change in the D-value of a microorganism.
Which of the following is NOT a colligative property exploited in food preservation?
Answer: Surface tension reduction
Surface tension is not a colligative property; colligative properties depend on solute concentration, not identity.
In extrusion processing of food, the 'specific mechanical energy' (SME) input affects:
Answer: Starch gelatinization, protein denaturation, and product expansion
SME drives the thermomechanical transformation of ingredients, affecting starch gelatinization, protein structure, and the expansion ratio of the extrudate.
What is the primary purpose of blanching vegetables before freezing?
Answer: To inactivate enzymes that cause quality deterioration
Blanching inactivates enzymes such as peroxidase and lipoxygenase that would otherwise cause color, flavor, and texture degradation during frozen storage.
The Maillard reaction in food processing requires which two types of reactants?
Answer: Reducing sugars and amino acids
The Maillard reaction is a non-enzymatic browning reaction between reducing sugars and free amino groups of amino acids or proteins.
In food rheology, a fluid whose viscosity increases with increasing shear rate is classified as:
Answer: Dilatant
Dilatant (or shear-thickening) fluids exhibit increasing viscosity as shear rate increases, unlike pseudoplastic fluids which thin under shear.