Unit 3: Plants and Plant Products of Industrial Value

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Vegetable Oils and Fats

Oils and fats are major reserve food materials in plants, primarily found in seeds and fruits.

Edible Oil-Yielding Plants

These oils are used primarily for cooking and human consumption.

• Groundnut (Arachis hypogaea):
  • Morphology: Herbaceous annual; fruit is an indehiscent legume produced underground (geocarpy).
  • Extraction: Crushing the seeds (kernels).
  • Uses: Cooking oil, margarine, and health implications include high protein content but also potential allergens.
• Coconut (Cocos nucifera): Yields oil from the dried endosperm (copra).
• Soybean (Glycine max): High in polyunsaturated fats; extracted from seeds.
• Mustard (Brassica spp.): Extracted from seeds; widely used in Indian cooking.

Non-Edible Oil-Yielding Plants

These are used for industrial purposes like soap making, lubricants, or biofuels.

Sugar and Starches

Sugarcane (Saccharum officinarum)

• Morphology: A tall perennial grass with thick, segmented stalks.
• Processing: Extraction of juice by crushing, followed by clarification, evaporation, and crystallization.
• By-products:
  • Molasses: Used for alcohol production.
  • Bagasse: Fiber residue used for paper and fuel.
  • Press mud: Used as fertilizer.

Potato (Solanum tuberosum)

• Morphology: Underground modified stem known as a tuber.
• Propagation: Vegetatively via "eyes" or tuber pieces.
• Post-harvest: Requires cold storage to prevent sprouting and starch degradation.

Fibres

Fibres are elongated, thick-walled cells that provide structural support to plants.

Classification Based on Origin

• Surface Fibres: Found on the surfaces of seeds or fruits (e.g., Cotton, Coir).
• Soft/Bast Fibres: Found in the phloem of stems (e.g., Jute).
• Hard/Leaf Fibres: Found in the vascular bundles of leaves (e.g., Sisal).

Specific Fibre Crops

• Cotton (Gossypium spp.): Seed surface hair; extracted by ginning.
• Jute (Corchorus spp.): Bast fibre from the stem; extracted by retting (soaking in water to rot off soft tissues).
• Coir (Cocos nucifera): Extracted from the fibrous husk (mesocarp) of the coconut.

Rubbers

Rubber is a secondary metabolite (latex) produced by specialized cells called laticifers.

Natural/Para Rubber (Hevea brasiliensis)

• Tapping: The process of making a controlled incision in the bark to collect latex.
• Processing: Latex is coagulated using acids (like acetic acid), pressed into sheets, and smoked or air-dried.
• Uses: Tires, footwear, surgical gloves, and industrial belts.

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