1 egypt (5.000 years ago ) reaping in ancient egypt. bread is also found in tombs. use of dough made...
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EGYPT (5.000 YEARS AGO)Reaping in ancient Egypt. Bread is also found in tombs. Use of dough made the previous day = natural leaven
YEASTBeer and whisky processing residue – maybe invented by the Gauls
PURE CULTURE YEASTSaccharomyces cerevisiae – compressed or cream yeast.
EVOLUTION OF LEAVENING
ISRAEL (23.000 YEARS AGO)Evidence of wheat grinding kmowledge found at Ohalo IIProf. Ehud Weiss, Nature 2004
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BIOLOGICAL LEAVENING (both production and retention of gas are important)
- compressed yeast- leaven
CHEMICAL LEAVENING
reaction between salts(acid salts+bicarbonate)
- decomposition (ammonium bicarbonate)
LEAVENING IN PHYSICS- air absorption (often with the help of eggs or emulsifyers)(ex. meringues, battered pastries, sponge cakes )
STEAM LEAVENING-puff pastry (the numerous layers of fat form a barrier against
steam)- cream puff
MIXED SYSTEMS (biological + lamination with fat)- danish pastry
LEAVENING
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ITALIAN LAW Decree n. 502 of November 30, 1998
Art. 8 1. The yeast suitable for bread-making must be composed of (mostly)alive cells with adequate fermentative power, humidity not higher than 75% and ashes not higher than 8%of dry matter 2. The yeast cream suitable for bread-making must be composed of (mostly) alive cells with adequate fermentative power , humidity not higher than 80% and ashes not higher than 8% of dry matter.I
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WHAT ARE WE TALKING ABOUT?
YEAST: LIVING CELLS, MAINLY SACCHAROMYCES CEREVISIAE, EMPLOYED IN BREAD-MAKING AS COMPRESSED YEAST.
NATURAL OR ACID LEAVEN: FROM SPONTANEOUS LEAVENING OF A DOUGH OF SOFT WHEA T (OR OTHER CEREALS ), USUALLY DERIVED FROM PREVIOUS SESSIONS OF BREAD-MAKING IN ORDER TO HAVE AT THE SAME TIME A DOUBLE BLASTOMYCES MICROFLORA AND BACTERIA, MAINLY LACTOBACILLUS.
MICRO-FLORA OF NATURAL LEAVEN : DERIVES FROM AN ENVIRONMENTAL CONTAMINATION OF RAW MATERIAL. THE WORKING CONDITIONS INSTEAD ALLOW THE DEVELOPMENT OF PARTICULAR MICRO-ORGANISMS AND PERMIT TO MAINTAIN THE MICRO-FLORA WHICH, IN ANY CASE, IS NOT CONSTANT. THE SPECIES DEPEND ALSO ON THEIR CAPACITY TO COHABIT (TOLERANCE TO ORGANIC ACIDS AND TO ANTIBIOTICS PRODUCED BY LACTICS AND USE OF CARBON SOURCES).
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FERMENTATION
(absence of oxyigen)
SACCHAROSE GLUCOSE
PIRUVATE
C02
ETHYL ALCOHOL
ENERGY BALANCE
2 ATP (2x7 = 14 Kcal)
ENERGY
C6H12O6 2CO2 + 2C2H5OH + Qkcal
LEAVEN ENERGY METABOLISM
RESPIRATION
(presence of oxygen)
CYCLE OF TRICARBOSSILIC
ACIDS
C02
2H+
0=
ENERGY
H20
RESPIRATION CHAIN
OXYGEN
ENERGY BALANCE
2 + 36 ATP (38 x 7 = 266 Kcal)
C6H2O6 + 6O2 6H2O+ 6CO2 + Qkcal
NB –INSIDE A DOUGH RESPIRATION CHANGES TO FERMENTATION IN A FEW SECONDS. IN ANAEROBIOSIS S.CEREVISIAE FERMENTS, I.E. TRASFORMS SACCAROSE INTO CARBON DIOXIDE AND ALCOHOL, BUT IT CAN’T MULTIPLY.
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GASES INVOLVED IN LEAVENING
CO2 - fermentation - carbon dioxide is highly soluble in water - bicarbonates (Na)
AIR - kneading -low water-solubility of nitrogen, which remains after the process since the oxygen is consumed by the yeast
NH3 - ammonium -it doesn’t leave salt residues;
bicarbonate it is used in low humidity final products
STEAM - formed by water - limited effect due to the high boiling
temperature
ETHANOL - from yeast fermentation - highly water-soluble, makes evaporate EXHAUST l’azeotrope (78°C)
GAS ORIGIN OBSERVATIONS
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LEAVENING TEXTURES
BIOLOGICAL LEAVENING - compressed yeast
CHEMICAL LEAVENING- chemical yeast
STEAM LEAVENING- puff pastry
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FORM PRESERVATION PRESERVATION ADDED CONVERSION FACTOR TEMPERATURE TIME % HUMIDITY METHOD
fresh, compressed 2 - 7°C 3 - 4 weeks 67-72 add to other ingredients or 1( 0,5 kg and 20kg wash away before kneading in acqua prima dellopackages)
fresh, crem 1 - 4°C 10 - 14 days 80 add to other 1,5(semi-liquid) ingredients
(decree 30.11.98)
dry, active room 3 - 12 months 6 - 8 hydrate at 30-43°C 0,4-0,5 temperature for 10-15 minutes before use
dry, instant room temp. 6 -12 months 4 - 6 mix with dry ingredients 0,3-0,4 in modified atm.
( pizza kits)
YEAST
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LEAVEN
SPONTANEOUSLY LEAVENED DOUGH
OR
ACID DOUGH
OR
NATURAL LEAVEN
=
From: R. Foschino, A.Galli, 1997
“obtained by spontaneous fermentation of a dough made with water and wheat, rye, oat…”
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• POWDERED ACID DOUGHS ARE ON SALE, WITH THE CHARACTERISTICS OF LEAVEN
• THEY ARE MAINLY USED FOR WHEAT OR RYE ACID BREAD (RATIO: 1-2% OF THE FLOUR)
• OBTAINED WITH THREE-KNEADING FERMENTATION FOLLOWED BY DRYING
• THESE PRODUCTS DIFFER IN pH (3,2 - 4,0 ) AND ACIDITY
• EMPLOYED IN BIOLOGIC BREAD MAKING BECAUSE THErE CAN’T BE USED AMELIORATORS
ACID DOUGH
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DIFFERENT EMPLOYMENTS OF LEAVEN BASICALLY, THERE ARE FOUR TYPES OF EMPLOYMENT OF LEAVEN
TRADITIONAL METHOD OF RYE BREAD MAKING, USED IN EASTERN EUROPE AND IN GERMANY. ESSENTIAL TO REDUCE THE ACTION OF AMYLASES PRESENT IN RYE COUNTRY LEAVEN EMPLOYED FOR RURAL BREAD , MAINLY USED IN FRANCE, SPAIN, PORTUGAL AND GREECE. SAN FRANCISCO ACID BREAD, USED IN CALIFORNIA TO MAKE AN ACID AND SOFT BREAD TYPICAL OF THE AREA. FESTIVITY BREADS (PANETTONE, PANDORO, EASTER DOVES) IN ITALY
IF THE FOUR METHODS ARE SLIGHTLY DIFFERENT, THE FUNDAMENTAL PROCEDURE IS THE SAME:
MAKE A FERMENTED DOUGH WHICH ACTS AS LEAVENING AGENT IN THE PROCESS.
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FUNCTIONS OF LEAVEN
PRIMARY FUNCTION: LEAVENING OF THE PRODUCT THROUGH THE FORMATION OFCARBON DIOXIDE AND ALCOHOL ( 1 glucose = 2 ethanol + 2 CO2) WHICH, MAINLYWHILE BAKING, TEND TO INCREASE THE VOLUME OF THE PRODUCT.
OTHER FUNCTIONS: THE BACTERIA (LACTOBACYLLUS, LATTOBACILLI, MA ANCHE PEDIOCOCCHIS, ENTEROCOCCHIS AND LEUCONOSTOC), PRODUCE
ORGANIC ACIDS, AROMATIC SUBSTANCES, CO2 (50% OF TOTAL CO2) AND ENZYMES WHICH AFFECT
• REDUCTION OF COOLING SPEED, ALSO WIT THE PRODUCTION OF ETERO-ESO-POLYSACCHARIDES (GLUCANS ex.dextrans, OLIGOFRUCTANS ex inulin) • FRAGRANCE
COMPLEX EVOLVING BIOLOGICAL SYSTEM
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LACTIC BACTERIA
Acidifying (lactic acid, acetic acid)
Selection of microflora
• Acts on amylase and protease
• Improves the reologycal properties
• It gives the capacity of binding the water
• Improves preservability (slow staling, antimicrobic action)
Proteasic and peptidasic action:
•precursors of aromatic composts (leucine, ornitine, iso-leucine,valine, methionine)
•oxidizing compost (they contribu te directly to the flavour
•Stimulation of the growth of the leaven and of other bacteria (alanine, valine, serine)
Important metabolic actions
Aromatising
• stimulation of the production of isohalcools by the leaven
• reaction of Maillard and Strecker
Proteolytic
ROLE OF MICRO-ORGANISMS
Production of esopolisaccharids• glucans and/or dextrans
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LEAVEN* BACTERIA
Saccharomyces
Debariomyces
Hansemula
Pichia
Torulaspora
Cryptococcus
Rhodotorula
Candida
Issatchenkia
Candida
Lactobacillus
Pediococcus
Leuconostoc
Weissella
S. cerevisiae
S. exiguus
L. sanfranciscensis, L. pontis, L. panis, L. plantarum, L. brevis, L. reuteri,
ACID DOUGH MICRO-FLORA
* ACID RESISTANT
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THE MAKING OF
LEAVEN…
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1st COOLING
2nd COOLING
3rd COOLING
*region in Northern Italy LEAVEN
LEAVEN CYCLE – WATER COOLING METHODO (Piedmont* school)
IT IS CALLED“ WATER COOLING” BECAUSE THE ACID DOUGH IS KEPT IN WATER, WITH NO NEED TO WRAP THE STARTER OR “MOTHER” IN A CLOTH AND TIE IT WITH A STRING
Dough temperature 22-25°C
MOTHERt 0’
MOTHERAfter 3 hours
18 hours at 4°C
3 h at 30°C – The volume doubles
3 h at 30°C – The volume doubles
3 h at 30°C – The volume doubles
Ratio 1st cooling./flour 1:1 + 0,5 H2O a 30°C
Ratio 2nd cooling./flour 1:1 + 0,5 H2O at 15°C
Flour 1 Water 0,35 at 30°C 1
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LET’S MAKE THE LEAVEN
JUST AFTER THE COOLING (by immersion)
THREE HOURS AFTER THE COOLING
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THE STARTER OR “MOTHER” OF LEAVEN (“TIED MOTHER” METHOD)
For the “night rest” the dough can be tied with a string (greater anaerobiosis)
or
kept in a bowl, in different conditions for the growth of lactobacylli.
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THE STARTER OR “MOTHER”
TIED “MOTHER”
UNWRAPPED “MOTHER”
LEAVEN ADVANTAGES AND DISADVANTAGES
ADVANTAGES
•Softer and more elastic
•Keeps soft for longer
•Better crust
•Can be kept for a long time because it inhibits moulds.
DISADVANTAGES
•Long process
•Difficult to stabilyze
•Risk of contamination
•High M.O. costs
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DIFFERENT METHODS
THESE ARE NOT THE ONLY LEAVEN-MAKING METHODS. THERE ARE MANY MORE: THE ONLY LIMIT IS OUR IMAGINATION.
GOOD RESULTS ARE OBTAINED WITH KNOWLEDGE AND SKILLS, BUT ABOVE ALL DISCIPLINE AND PERSEVERANCE.
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