Pp bread making operations
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This document outlines the key steps in the bread making process: 1. Fermentation involves physical and chemical changes as yeast converts sugars into carbon dioxide and alcohol, causing the dough to rise in temperature, volume, and soften in consistency. 2. Dough making includes dividing, scaling, rounding, proofing, and molding the fermented dough. 3. Baking is the most important step, causing physical changes like oven spring and chemical changes such as starch gelatinization and gluten coagulation that give bread its final structure and color. 4. The entire process is carefully controlled to maximize gas production and retention for an evenly risen final loaf.
Pp bread making operations
- 1. STEPS IN BREAD MAKING OPERATIONS FERMENTATION- PHYSICAL / CHEMICAL FERMENTATION CONTROL GAS PRODUCTION GAS RETENTION FERMENTATION LOSSES KNOCK BACK DOUGH MAKE-UP- DIVIDE/SCALE/INTERMEDIATE PROOF/MOULDING PANNING FINAL PROOF BAKING / STEAMING / COOLING
- 2. 1. FERMENTATION PHYSICAL CHANGES INCREASE IN VOLUME INCREASE IN TEMPERATURE BY 5˚- 6˚C INCREASE IN NO. OF YEAST CELLS ( 26%-STRAIGHT DOUGH/ 56% IN SPONGE) LOSS OF MOISTURE CHANGE IN CONSISTENCY – SOFT, ELASTIC , EXTENSIBLE. CHEMICAL CHANGES Ph REDUCES FROM 5.5 TO 4.7 DUE TO PRODUCTION OF ACETIC, LACTIC,SULPHURIC AND HYDROCHLORIC ACIDS FORMATION OF MALTASE BY DIASTATIC ENZYMES ACTING ON STARCH PRODUCTION OF CO₂ AND ALCOHOL BY ENZYMATIC REACTIONS MELLOWING OF GLUTEN BY PROTEOLYTIC ENZMES FERMENTATION TIME DEPENDS ON -TYPE OF FLOUR -QUANTITY OF YEAST -TEMPERATURE OF DOUGH -PRESENCE OF YEAST FOOD
- 3. ENZYMES ENZYMES ARE PROTEINS AND A GIVEN ENZYME WILL WORK ONLY ON A CERTAIN SUBSTRATE AND ONLY DO A VERY SPECIFIC JOB ALTHOUGH THEY TAKE PART IN A CHEMICAL REACTION, THEY DO NOT CHANGE THEMSELVES BECAUSE THEY ARE PROTEINS ,THEY ARE HEAT SENSITIVE THEY HAVE AN OPTIMUM TEMPERATURE AND Ph FOR ACTIVITY WITHIN THAT RANGE, ACTIVITY INCREASES WITH TEMPERATURE UNTIL DENATURATION POINT IS REACHED. THE 3 MAIN ENZYMES COMMONLY ENCOUNTERED IN THE BAKERY ARE:- 1. AMYLASES i.e. α AMYLASE AND β AMYLASE. 2. PROTEASES. THEY REACT WITH PROTEINS AND WEAKEN THEM THEREBY REDUCING MIXING TIME AND IMPROVING MACHINEABILITY. 3. LIPOXYGENASES. THIS ENZYME FOUND IN SOY FLOUR BLEACHES THE FLOUR THEREBY GIVING A WHITER CRUMB.
- 4. AMYLASES AMYLASES CONVERT STARCH INTO SUGARS. α AMYLASE CLEAVES THE STARCH RANDOMLY INTO SMALLER UNITS CALLED DEXTRINS. β AMYLASE CUTS OFF 2 UNITS AT A TIME FROM THE END OF THE STARCH CHAIN. THE MORE α AMYLASE THERE IS, BETTER FOR THE β AMYLASE BECAUSE THERE ARE MORE EXTREMITIES AVAILABLE. SO THE SUBSTRATE FOR THE β AMYLASE IS EITHER STARCH OR DEXTRINS AND THE PRODUCT IS MALTASE. FLOURS TEND TO LACK α AMYLASE AND THE MILLER HAS TO SUPPLEMENT THIS. EITHER FROM A CEREAL SOURCE(MALTED BARLEY), FUNGAL SOURCE OR A BACTERIAL SOURCE. MALT IS PRODUCED BY GERMINATING BARLEY WHERE THE KERNEL PRODUCES A LOT OF ENZYMES, MAINLY AMYLASES AND PROTEASES. WHEN THESE ENZYMES ARE EXTRACTED, IT LEADS TO DIASTATIC MALT SYRUP- i.e. IT CONTAINS ACTIVE ENZYMES. IT IMPROVES DOUGH HANDLING, PROVIDES MORE FOOD FOR YEAST, FLAVOUR, CRUST AND CRUMB COLOUR AND INCREASES SHELF LIFE. NONDIASTATIC MALT IS TREATED IN SUCH A WAY THAT THE ENZYMES WILL DENATURE ( DEACTIVATED). IT AIDS IN FERMENTATION, CRUST AND CRUMB COLOUR AND FLAVOUR. THE ACTIVITY OF ALPHA AND BETA AMYLASE IS KNOWN AS DIASTATIC ACTIVITY.
- 5. 2. FERMENTATION CONTROL IT IS IMPORTANT TO HAVE THE DEVELOPMENT OF GAS PRODUCTION AND GAS RETENTION CAPACITIES AT A PARALLEL AND EVEN RATE. 3. GAS PRODUCTION INCREASES WITH ADDITION OF SUGAR AND MALT/ YEAST / YEAST FOOD/ HIGH TEMP OF THE DOUGH (35˚C) DECREASES WITH ADDITION OF SALT/ EXCESS YEAST FOODS/ EXCESS TEMP (>35 ˚C) 4. GAS RETENTION DEPENDS ON CHEMICAL AND PHYSICAL FACTORS SUCH AS MINERALS, MOISTURE,PH, PROTEOLYTIC ENZYMES AND OXIDIZING AGENTS, MIXING, DOUGH EXPANSION, KNOCK BACK, DIVIDING, ROUNDING AND MOULDING. 5. FERMENTATION LOSSES. AVERAGE CONDITIONS WEIGHT LOSS IS 1% ( 0.5-4%). DUE TO LOSS IN MOISTURE WHICH DEPENDS ON TEMP. AND RELATIVE HUMIDITY AND A LITTLE TO CO₂ ESCAPE.
- 6. 6. KNOCK BACK EXPELS CO₂, ADDS NEW OXYGEN THEREBY STIMULATES YEAST ACTIVITY, EQUALISES DOUGH TEMPERATURE, INCREASES GAS RETENTION CAPACITY AND AIDS MECHANICAL DEVELOPMENT OF GLUTEN. 7. DOUGH MAKE UP DIVIDE, SCALE, ROUND, INTERMEDIATE PROOF AND MOULDING 8. PANNING. PLACING THE MOULDED DOUGH SEAM DOWN INTO A GREASED PAN 9. FINAL PROOF RELAXES THE DOUGH, GIVES GOOD, MELLOW AND EXTENSIBLE GLUTEN. 10. BAKING THE MOST IMPORTANT STEP IN BREAD MAKING.
- 7. BAKING – PHYSICAL CHANGES 1. FILM FORMATION (CRUST) 2. OVEN SPRING. THE SUDDEN EXPANSION OF THE DOUGH DUE TO EXPANSION OF GASES AND FINAL YEAST ACTIVITY BY ABOUT 1/3rd THE ORIGINAL SIZE. 3. OVEN SHRED. THE FINE STRETCH MARKS VISIBLE AT THE SIDES OF THE LOAF SHOWING A WELL CONDITIONED DOUGH AND GLUTEN. BAKING – CHEMICAL CHANGES 1. YEAST ACTIVITY 2. STARCH SWELLS AND GELATINIZES FROM ABOUT 54˚C 3. GLUTEN COAGULATION WHICH SETS IN AT ABOUT 74˚C THE MAJOR CHANGE IS THE REDISTRIBUTION OF WATER FROM THE GLUTEN PHASE TO THE STARCH PHASE. 4. ENZYME ACTIVITY. AMYLASE ACTION ON STARCH INCREASES UP DENATURIZATION BETWEEN 57˚C AND 72˚C. 5. SUGAR CARAMELIZATION. 6. BROWNING REACTION. STARTS AT 160˚C. IT IS THE RESULT OF HEATING AND REDUCES SUGARS WITH FREE AMINO ACIDS, PEPTIDES OR PROTEINS TO FORM COLOURED COMPOUNDS CALLED MALANOIDINS ( GIVES COLOUR AND FLAVOUR TO BREAD) STEAMING –GLOSSY CRUST/PREVENTS SPLIT CRUST/ AGITATES EVEN ATMOSPHERE COOLING