3- Preparing Raw Materials Containing Complex Carbohydrates Flashcards
Complex carbohydrates
Grains, potatoes, agave, starch & fructans, long chains of sugar (glucose or fructose), more stable way for plants to store sugars
Starch
In all grains (barley, corn, wheat, rye, rice, sorghum), potatoes, formed in plant cells by bonding glucose molecules, as bond forms, a molecule of water released, can contain 10’s of 1000’s of glucose molecules, wrapped into tight granules for easier storage
Starch conversion
3 elements: modification, gelatinisation, enzymatic hydrolysis
Modification
Only for grains, starch granules not stored in living cells, kept in 3-D protein net, needs to be broken down to release starch granules
Gelatinisation
Starch granules insoluble but if exposed to water over a period of time, they start to unravel & become soluble in water, can be sped up with heat
Enzymatic hydrolysis
Once starch granules unraveled enzymes needed to break them into individual glucose molecules, enzymes not used up or destroyed so small amount needed, speed is temp dependent, inactive if too cold, effectiveness increases with rise in temp, all have optimum temp, if too high become ineffective or can be destroyed
Enzymes
Catalysts that start reactions that might not otherwise happen or speed up rate of reactions
Hydrolysis
To break each bond between individual glucoses in starch, a molecule of water is required
Amylase
Enzymes required to break up starch
Cereal plant
Grow from a grain, die in a single year, flowers & seed (grains), contain embryonic plant with store of starch to feed on
Husk
Hard outer covering, protects
Bran
Different layers, for barley has important role in creation & release of enzymes
Germ
Part that grows into new plant when conditions warm & damp, germination
Endosperm
Where starch granules stored, grain ripens & starch granules secured in 3-D protein net
Making green malt
1- grain is dormant
2- initial phase when grain swells with water
3- 1st visible signs of growth, root emerges
4- roots clearly id’ed, growth halted, modification completed & amylase enzymes released, roots removed
Glucose to starch to glucose
1- plant bonds up to 20,000 glucose molecules releasing water
2- plant rolls up large starch molecules into tight granules & stores them in protein net
3- modification- protein net broken by enzymes or heat
4- gelatinisation- heat used to unravel starch molecules making them soluble
5- enzymatic hydrolysis- amylase helps water react with glucose in starch, breaking bonds, no limit to # of times enzyme performs this task
European traditions for converting starch
Malting, relies on enzymes from barley (endogenous enzymes)
Making a sugary liquid from barley
2 stages:
1- malting (modification takes place)
2- milling & mashing (gelatinisation & enzymatic hydrolysis occur)
Malting
Tricks grain into starting to grow (germination), warm location, soak with water, drained & soaked again several times, grain swells, shoots & roots appear, constantly turned, stops root from knotting together, releases heat generated & keeps at constant temp, ensure all grown at same rate
Green malt
Growth continues, roots as long as grain
Kilning
Growth stopped, heated & dried (warm, dry air), modification & enzyme release needs to be complete before kilning
- If too early- protein structure not broken down & difficult for enzymes to access, may not be enough enzymes
- If too late- too much starch consumed by plant while growing, reducing amount of sugar available
Malted barley
Once dried any attached roots removed, stored in cool, dry conditions, can store for several months
Milling
Cracks open grains creating grist, makes starch more accessible for mashing
Grist
Particles of various sizes, from large husk fragments to flour
Mashing
Starch in barley 1st gelatinised & then enzymatic hydrolysis, grist mixed with warm water, temp control is key: too high- enzymes can be destroyed, too low- enzymes work too slowly & conversion may not complete
Optimal Temperature for Mashing
63-64 C, 145- 147 F, optimal for gelatinisation of starch & for enzyme efficiency
Wort
After 1 hour most starch converted to sugar, sweet liquid (wort) drained, husk held back & act as filter for remaining solids, wort cooled & sent to fermenter
Sparging
Solids separated from wort sprayed with hot water min 2x, flushes out remaining starch or sugars, also sent to fermenter, hot water ensures all remaining starch is gelatinised
Fermenter
Starch to sugar conversion rarely fully complete, continues during fermentation, wort vulnerable to spoilage so risk of waiting too high
Distiller’s malt
Malt of choice in Scotland, pale, min amount heat used, ensures all enzymes & starch preserved, maximizes yield of alcohol
More heat during malting
Grains darker, develop caramel & nutty flavours, extremely high heat creates roasted, chocolate aromas, can destroy enzymes, can also change starch so it can’t be converted into sugar, used by brewers, some distillers use for extra dimension of flavour
Other grains
Rare to be malted, usually milled & cooked in water before being mixed with malted barley or enzymes
Cooking grains
Batch process, atmospheric pressure or in pressurized ovens with slightly higher temps
Cooking achieves 2 things
1- heat breaks up protein net in endosperm
2- gelatinises starch granules
Operational temperature of cooker
Depends on grains, starch granules in different species have slightly different structures, if using > 1 grain then temp needs to be dropped, grain with highest gelatinisation temp always added 1st, lowest last
Temperature after cooking
Dropped to 64 C (147 F)
Conversion of all starches
Malted barley added (small % of the mash), special varieties produce high levels of enzymes to make sure conversion not too slow (decreases risk of spoilage), wort drained after 1 hour & sparged as required, usually drained before conversion complete
Other sources of enzymes
Can supplement or replace malted barley with exogenous enzymes, nearly all animals, bacteria & fungi produce amylase enzymes, use controlled by local laws, not allowed in Scotch but American whiskey can use
Enzymes from fungi
Grown in controlled conditions on starchy material, release enzymes that are harvested, packaged & sold
Potatoes
Have to be cooked, no equivalent to malting, sequential process controlled by individual cells working cooperatively, can’t release all enzymes in one go
Cooking Potatoes
Pressurized steam oven, breaks down the potatoes’ cells releasing starch, then gelatinised, once completely broken up & mixed with water, temp dropped to 64 C (147 F), enzymes added
Europe
Traditionally malted barley added, now commercial enzymes used
Japan
Traditionally & currently use koji
Asian traditions for converting starch
Malted barley imported to Asia (Japan) in early C20th
Filamentous fungi
Enzymes made by filamentous fungi or occasionally bacteria, used in production of baiju, shochu & soju
3 stages
1- raw material containing starch (grain) steamed to gelatinise starch
2- selected fungi (or bacteria) grown on small amount of starchy material, secrete amylase enzymes as they grow, also release enzymes needed for modification
3- starchy material (full of enzymes) mixed with larger amount of raw material containing gelatinised starch, various fungal enzymes undertake both modification & enzymatic hydrolysis
Parallel fermentation
Starch to sugar conversion happens during alcoholic fermentation
Growing filamentous fungi
Can be grown from seeds (spores) or existing active population, need warmth & humidity, produce long, branching filaments that spread through starch, different enzymes secreted through filaments, some are amylases- to digest material they are growing through to break it down into nutrients, including fermentable sugars, fungi then absorb nutrients through filaments for energy
If grains used
Some fungal enzymes can complete any modification not done during cooking
Aim
Not concerned with how much sugar they consume, aim to create just enough enzymes then stop fungal growth by cooking & drying
China & Korea
Made into solid cake
China- qu
Korea- nuruk
Japan
Fungi grown on individual cereal grains or small pieces of sweet potato, koji
Fructans
Complex carbohydrates made of fructose, made by many plants, ex agave, molecules smaller than starch molecules, found in different configurations
Inulin
One configuration of fructans, agave has other types of fructans
Hydrolysis
Same reaction to break fructans into fermentable sugars, 1 water molecule needed to separate individual sugars, agave plant does this using enzymes, distillers don’t need to use enzymes, just need to cook fructans
Fructan conversion
Agave stores fructans in large, central core protected by spiky leaves, harvested by hand
Pina
Roots & leaves cut away leaving solid core
Cooking pinas
Achieves 2 things:
1- converts fructans into sugar
2- weakens & softens pinas structure, degrades cell walls, breaks some cells open, pina is soft & pliable
Aguamiel
Sugar that drains out of cooked pinas
Crushing & milling
Most sugar extracted, squeezes out sweet liquid from broken down cells, breaks up other cells to release contents, crushed fibres washed through with water
Cooking extracted juice
Some pinas not cooked, processed in diffuser, pinas shredded & mixed with hot water & sometimes small amount of strong acid, creates liquid full of fructans, liquid cooked to create fermentable sugars
