Basic Principles of Vegetable Cooking — Pigments, Composition, Selection, Cuts & Nutrient Preservation
Basic Principles of Vegetable Cooking — Pigments, Composition, Selection, Cuts & Nutrient Preservation
The colour of a vegetable tells you how to cook it. Anthocyanin leaches in water. Chlorophyll turns olive drab in acid. Carotenoids survive heat. Mastering vegetable pigments is the key to professional vegetable cookery.
Vegetables used: in curries, salads, garnishing · as stuffing (mashed potato) · as thickening agents in gravies and soups (potatoes in chowder) · in chutneys and relishes (onion, tomato, mint, coriander) · as integral ingredients (biryani, risotto, meat preparations).
Composition: Vegetables have 70–95% water content. Carbohydrates (starch, sugar, cellulose, pectin) rank first. Starch is chief nutrient of roots and tubers — potatoes have highest %. Sugar highest in beetroot, also rich in carrots and turnips. Cellulose (roughage) becomes coarser and tougher as vegetables mature.
Tannins: Complex organic compounds in plants. Astringent properties. Form greenish-purplish compounds with tannic salts — turn brown upon oxidation (responsible for browning in cut vegetables).
| Vegetable | Selection | Storage |
|---|---|---|
| Onion | Thin shiny skin, no signs of sprouting | Room temp ~24°C |
| Cabbage | Compact, heavy for its size | 4–5°C refrigerator |
| Carrots | Smooth skin, not wrinkled | 10–12°C refrigerator |
| Potato | Regular size, free from earth/blemishes | Cool dark place |
| Garlic | Pods dry, firm and plump | Dry place |
| Mushroom | White, fresh, unbleached, short stems | Refrigerated |
| Ginger | Large, thin skin, snaps with crack | Cool dry place |
| French Beans | Light green, long, crisp — snaps when bent | Refrigerated |
| Beetroot | Dark crimson, smooth tender surface, not fibrous | Refrigerated |
| Spinach | Tender leaves, narrow stems | Refrigerated |
◆ Highest starch: Potato · Highest sugar: Beetroot (also rich in carrots, turnips)
◆ 5 pigments: Chlorophyll (green) · Carotenoid (yellow/orange) · Anthocyanin (red/purple) · Flavones (white) · Betalains (beet)
◆ Most stable pigment: Carotenoid · Most water-soluble: Anthocyanin and Betalains
◆ Betalains: contain nitrogen, found only in beetroot, highly water-soluble
◆ Tannins = astringent compounds → brown on oxidation (browning of cut vegetables)
◆ Flavouring: volatile aromatic oils = characteristic flavour and odour
◆ Vegetable cuts: Julienne, Jardinière, Macédoine, Brunoise, Lorenge, Chiffonade, Paysanne
◆ Chlorophyll preserved by: quick cooking in uncovered pot (acid vapours escape)