Culinary Terms Test: Gelatinization, Retrogradation, and Starch Behavior

📚 Quick Study Guide

• 🧪 Gelatinization: The process where starch granules absorb water and swell when heated, leading to increased viscosity. It's influenced by factors like starch type, water availability, temperature, and pH. Occurs typically between 60-75°C (140-167°F).
• 💧 Retrogradation: The recrystallization of amylose molecules in gelatinized starch upon cooling. This results in a gritty texture and syneresis (water expulsion). Factors affecting retrogradation include starch type, concentration, storage temperature, and time.
• 🌡️ Starch Composition: Starch is composed of two main polysaccharides: amylose (linear) and amylopectin (branched). Amylose contributes to gel formation, while amylopectin affects viscosity and prevents excessive retrogradation. The ratio of amylose to amylopectin varies among different starches.
• 💡 Key Factors Affecting Starch Behavior:
  • 💧 Water Availability
  • 🔥 Temperature
  • 🍋 pH
  • 🧂 Presence of Sugars and Fats
• 📈 Viscosity Changes: As starch gelatinizes, viscosity increases. Upon cooling, retrogradation can lead to a decrease in viscosity and the formation of a gel or a grainy texture.

Practice Quiz

1. Which of the following best describes gelatinization?
   1. Heating starch in the absence of water.
   2. Cooling starch to form crystals.
   3. Heating starch in water, causing granules to swell.
   4. The breakdown of starch into simple sugars.
2. What is the primary cause of retrogradation in starches?
   1. The absorption of water by amylopectin.
   2. The recrystallization of amylose molecules.
   3. The rapid heating of starch solutions.
   4. The addition of acids to starch mixtures.
3. Which component of starch is primarily responsible for gel formation?
   1. Glucose
   2. Amylopectin
   3. Amylose
   4. Fructose
4. At what approximate temperature range does gelatinization typically occur?
   1. 0-20°C (32-68°F)
   2. 80-100°C (176-212°F)
   3. 60-75°C (140-167°F)
   4. 120-140°C (248-284°F)
5. What effect does a high sugar concentration typically have on starch gelatinization?
   1. Speeds up gelatinization
   2. Has no effect on gelatinization
   3. Inhibits gelatinization
   4. Causes immediate retrogradation
6. Which of the following starches would you expect to exhibit the LEAST amount of retrogradation?
   1. Cornstarch (high amylose)
   2. Wheat starch (moderate amylose)
   3. Rice starch (low amylose)
   4. Potato starch (moderate amylose)
7. What is syneresis, in the context of starch behavior?
   1. The swelling of starch granules
   2. The expulsion of water from a gel
   3. The formation of a smooth, glossy texture
   4. The breakdown of starch molecules