BIO5101 Notes Topic 141

BIO5101 Introduction to Biotechnology · (Topic 141-170) · Topic 141 – Biotechnology Role in Food · 1. Biofortification (Nutritional Enhancement)

Biofortification is the process of increasing the density of vitamins and minerals in a crop through genetic engineering.

1. Golden Rice: The most famous example. Rice is engineered with genes from daffodils and soil bacteria (Erwinia) to produce Beta-carotene (Pro-vitamin A). This helps combat Vitamin A deficiency, which causes blindness.
2. Iron/Zinc enrichment: Developing cereal crops with higher mineral content to address "hidden hunger" in developing nations.

2. Delayed Ripening (Shelf-Life Extension)

Fruits like tomatoes produce Ethylene gas, which signals them to ripen and eventually rot.

1. The Flavr Savr Tomato: The first GM food sold. Scientists used Antisense RNA technology to block the enzyme Polygalacturonase (PG). This enzyme breaks down pectin in cell walls; by blocking it, the tomato stays firm for longer, allowing it to ripen on the vine for better flavor without spoiling during transport.

3. Modification of Food Composition

Biotechnology allows us to change the "ingredients" within a plant to make them healthier:

1. Healthier Fats: Engineering oilseed crops (like canola or soybean) to produce high levels of Omega-3 fatty acids or reduced saturated fats.
2. Reduced Allergens: Using gene silencing to remove proteins that cause allergies in peanuts or wheat.
3. Sweetener Production: Producing low-calorie sweeteners like Stevia or Thaumatin in transgenic plants or microbes.

4. Food Processing and Enzymes

Biotechnology isn't just about the crops; it's about the tools used to make food:

1. Chymosin (Rennet): Traditionally taken from the stomachs of calves to make cheese. Today, most cheese is made using recombinant Chymosin produced by engineered yeast or fungi.

5. Safety and Detection

Biotechnology provides tools to ensure food safety:

1. Biosensors: Using engineered proteins to detect toxins or bacteria (E. coli, Salmonella) in food products instantly.
2. GMO Detection: Using PCR (Polymerase Chain Reaction) to verify if food contains genetically modified ingredients for labeling purposes.

1. Q: What is Golden Rice? A: A variety of rice engineered to produce beta-carotene, a precursor of Vitamin A.
2. Q: What does the enzyme Polygalacturonase (PG) do? A: It breaks down pectin in the cell walls of fruit, causing softening and rotting.
3. Q: Define " Biofortification." A: Improving the nutritional value of food crops through biotechnology or breeding.
4. Q: How was the Flavr Savr tomato created? A: Using Antisense RNA technology to silence the PG gene.
5. Q: What is the benefit of high-oleic acid soybean oil? A: It is more heat-stable for frying and contains less saturated fat, making it heart-healthy.
6. Q: Name the " Stress Hormone" in fruits responsible for ripening. A: Ethylene.
7. Q: What is Chymosin used for? A: It is an enzyme used to curdle milk in the cheese-making process.
8. Q: Why is Golden Rice yellow/orange? A: Because of the presence of beta-carotene (the same pigment found in carrots).
9. Q: What is " Hidden Hunger"? A: A form of malnutrition where people get enough calories but lack essential vitamins and minerals.
10. Q: How does biotechnology help people with peanut allergies? A: By using gene silencing to "knock out" the specific proteins (allergens) that trigger the allergic reaction.
11. Q: Explain the molecular strategy behind the development of Golden Rice. A: Rice naturally produces the precursor for beta-carotene (GGPP) in its leaves, but the pathway is "turned off" in the edible grain (endosperm). To fix this, scientists inserted two genes: psy (phytoene synthase) from Daffodil and crtI from the soil bacterium Erwinia uredovora. These genes provide the enzymes necessary to complete the biochemical pathway, allowing the rice grain to synthesize and accumulate beta-carotene. This biofortified rice can provide up to 50% of the daily Vitamin A requirement in a standard diet.
12. Q: Describe the mechanism of Antisense RNA technology in the Flavr Savr tomato. A: In a normal tomato, the PG gene produces mRNA, which is translated into the PG enzyme that softens the fruit. In the Flavr Savr tomato, scientists inserted a "reverse" version of the PG gene. This produces an Antisense RNA strand that is complementary to the normal " Sense" mRNA. The two strands bind together to form double-stranded RNA. The cell's machinery cannot translate double-stranded RNA into a protein, effectively "silencing" the PG enzyme and keeping the tomato firm.
13. Q: Discuss the advantages of Recombinant Chymosin over traditional Rennet. A: Traditional rennet is extracted from the stomach lining of slaughtered calves, which is expensive, inconsistent in quality, and ethically problematic for vegetarians. Recombinant Chymosin (FPC) is produced by inserting the bovine chymosin gene into microbes like Kluyveromyces lactis. This produces a pure, high-quality enzyme that is identical to the animal version but is cheaper, "vegetarian-friendly," and avoids the risks of animal-borne diseases.

Q4. Q: How can biotechnology be used to improve the fatty acid profile of cooking oils?

A: Scientists target the enzymes involved in the lipid biosynthetic pathway, such as desaturases. For example, by silencing the gene that converts oleic acid (healthy) to linoleic acid (less stable), they can create " High-Oleic" oils. These oils have a longer shelf-life, produce fewer trans-fats when heated, and offer cardiovascular benefits similar to olive oil, but in high-yield crops like soybean or canola.

5. Q: Evaluate the role of biotechnology in ensuring food safety and quality control. A: Biotechnology provides high-precision tools for monitoring. PCR-based assays can detect the DNA of pathogens like Listeria or Salmonella much faster than traditional culturing. ELISA tests use antibodies to detect toxins or allergens. Additionally, Biosensors (using bioluminescent bacteria or enzymes) can be integrated into food packaging to change color if the food begins to spoil or if harmful gases are produced, providing a real-time safety indicator for consumers.

Q1. Golden Rice was developed to address deficiency in:

1. Vitamin C
2. Vitamin A
3. Iron
4. Iodine

Correct answer: Vitamin A

Q2. The first genetically modified food to be commercially sold was:

1. Flavr Savr Tomato
2. Bt Corn
3. Golden Rice
4. Roundup Ready Soybean

Correct answer: Flavr Savr Tomato

Q3. The Flavr Savr tomato used ________ technology.

1. Gene Gun
2. Antisense RNA

Correct answer: Antisense RNA