Lecture: Enzymes That Ruin Your Desserts

Overview

• Topic: Proteins and Enzymes in Foods
• Focus: How certain enzymes affect the solidification of gelatin

Proteins

• Structure: Proteins are like a ball of yarn, made up of amino acids.
• Amino Acids: Building blocks of proteins, represented by different yarn colors (blue, green, yellow, pink, orange).

Digestion and Enzymes

• Digestion: Proteins need to be broken down into amino acids.
• Enzymes: Proteases act like scissors to break down proteins.
  • Protease Function: Cuts proteins into amino acids.

Demonstration with Gelatin

• Gelatin without Fruit: Solid, opaque, flips upside down without spilling.
• Gelatin with Fruits:
  • Strawberries, Canned Pineapple, Blueberries: Solid
  • Fresh Pineapple, Kiwi: Remained liquid

Explanation

• Collagen in Gelatin:
  • Flexible, tangled filaments trap water/sugar to solidify.
• Chemical Reaction: Gelatin solidifies by cooling.

Effects of Fruits on Gelatin

• Proteases in Fruits:
  • Fresh Pineapple, Kiwi: Contain protease, prevent solidification by cutting collagen proteins.
  • Canned Pineapple, Strawberries, Blueberries: Do not contain active proteases, allow solidification.

Canning Process

• Denaturation: Heat denatures protease in canned pineapple, allowing gelatin to solidify.

Practical Applications

• Meat Tenderizers: Similar enzyme action used in commercial meat tenderizers.
• Culinary Tips: Pineapple used on ham for tenderness due to protease.

Alternative: Agar Agar

• Vegan Gelatin:
  • Made from vegetable gum, not collagen.
  • Does not solidify due to absence of proteins for protease to act on.
  • Fresh Pineapple and Kiwi did solidify in agar agar.

Key Takeaways

• Fruits with Proteases:
  • Fresh Kiwi, Fresh Pineapple, Mango, Papaya
• Fruits without Proteases:
  • Strawberries, Blueberries, Canned Pineapple
• Practical Tip: Know which fruits to avoid in Jello to ensure solidification.