BAKING SCIENCE AND TECHNOLOGY Function of Ingredients in Bread Production Learning Objectives • Describe the functions of the major and minor ingredients in white pan breads: water, yeast, salt, sugar, fats and oils, mold inhibitors, and dough conditioners • Describe dough and bread attributes when specific ingredients are over and under dosed • Compare different forms of ingredients: dry yeast vs. compressed yeast vs. cream yeast; granulated sugar vs. HFCS, liquid milk vs. dry milk solids, etc. • Describe proper handling of specific ingredients © Copyright AIB International May not be reproduced without written permission. Function of Ingredients in Bread Production BAKING SCIENCE AND TECHNOLOGY Baking bread begins with combining the appropriate ingredients as outlined in a formula. Bakers combine various ingredients to make a wide variety of breads. Selecting the right ingredients makes the difference between producing excellent breads and poor quality breads. Any signifi cant change in ingredients will affect the fi nal product quality and customer satisfaction. A strong understanding of how individual ingredients function and how they interact in a dough system is critical. The most basic and ancient bread formulas consist of fl our, water, salt, and yeast. From that basic formula, thousands of varieties have been created. Breads may include ingredients such as milk, eggs, various fats, fruits, nuts, sweeteners, etc. Wheat and Flour Wheat fl our dough has the unique ability to retain the gas produced during yeast fermentation or by chemical leavening. The fl our is responsible for the characteristic structure of bakery foods. Wheat fl our is made from one or blends of six classes of wheat: durum, hard red spring, hard red winter, hard white, soft red winter, and soft white. Wheat Class Avg Wheat Typical Uses Protein % Durum 14-16% Pastas, spaghetti, macaroni Hard Red Spring (HRS) 13-14% Pan breads, rolls, buns Hard Red Winter (HRW) 11-12% Pan breads, artisan breads and rolls, pizza crusts Hard White (HW) 11-12% Noodles, flat breads, breads Soft Red Winter (SRW) 10% Cakes, pastries, biscuits, crackers Soft White (SW) 10% Asian noodles, flat breads, cakes, pastries, crackers Winter wheats are planted in the fall, germinate and begin to grow, and then become dormant during the cold winter months. They resume growth in the spring and are harvested during the early summer. For winter wheat to produce seed, it must undergo temperatures near freezing for several days. If the wheat does not encounter the cold, the plants become a grass and do not form kernels. This type of wheat grows in regions where the winters are moderate and relatively dry. © Copyright AIB International 2 May not be reproduced without written permission. Function of Ingredients BAKING SCIENCE AND TECHNOLOGY in Bread Production Spring wheats are planted in the spring and harvested in late summer. Spring wheats are grown in regions where winters are severe, and also in regions where winters are mild. Spring wheats generally have higher protein contents than do winter wheats (for hard spring and hard winter). There is an inverse relationship between grain yield and protein content of the grain; hard spring wheats have a lower yield of grain per acre than hard winter wheats. The terms “red” and “white” indicate the color of the wheat kernel, not the fl our milled from the wheat. The color comes from a single layer of cells in the pericarp. Red wheat is pigmented, and white is not. The color component contributes a bitter or astringent fl avor to the bran and to any fl our that contains high concentrations of bran, such as red whole wheat fl our. Hardness relates to the mechanical force required to crush a kernel. In hard wheats, the fi rst point of fracture is at the cell wall, rather than through the cell contents. In soft wheats, the fracture occurs primarily through the cell contents. Hard wheat varieties are generally higher in protein and are used principally in the production of yeast-leavened products. The soft wheats yield fl ours that are suitable for the production of chemically-leavened products such as cakes, pastries, cookies, crackers, doughnuts, pie crusts, etc. Durum wheat is used in the manufacture of macaroni, spaghetti, and similar pasta products. In the US, durum is grown in the same regions as hard red spring wheats. Durum is genetically different from the other wheats. It has 28 pairs of chromosomes: common wheat has 42. Durum wheat is also much harder in texture than common wheat. Durum is made into durum fl our and semolina. The wheat kernel consists of three major, distinct parts: germ, endosperm, and bran (pericarp). The structure and location of these parts are shown on page 4. © Copyright AIB International May not be reproduced without written permission. 3 Function of Ingredients in Bread Production BAKING SCIENCE AND TECHNOLOGY A Kernel of Wheat The largest part of the wheat kernel is the starchy ENDOSPERM (about 80% of the total kernel). The white flour produced during milling comes from the endo- sperm. The BRAN is the outer coat of the seed (pericarp). It is made up of several layers that protect the germ and endosperm and makes up 12-16% of the kernel. The GERM, or embryo, is the living part of the seed and makes up 2-3% of the kernel weight. The fact that the seed is living makes it easier to store. One of the great advantages of cereal grains is that they can be stored for long periods of time (several years under ideal conditions). The germ is also where growth of the new plant is initiated after the seed is planted. The ALUERONE layer surrounds the endosperm and is usually found in bran. It is one cell layer thick and is high in minerals, vitamins, phytonutrients, and protein. This protein is non-gluten forming. © Copyright AIB International 4 May not be reproduced without written permission. Function of Ingredients BAKING SCIENCE AND TECHNOLOGY in Bread Production The aleurone is the outer layer of the endosperm, and is often included as a portion of the bran. The pericarp is the outer protective layer of the kernel, and creates the majority of the bran portion. Chemically, the bran contains relatively large percentages of ash (inorganic minerals), fi ber (cellulose and arabinoxylans), and proteins. Some of these materials lower the quality of white fl our and most are removed in the milling process. The outer bran layers are tough because of their high cellulose content. This makes it easier to separate the bran from the endosperm during milling. The germ, or embryo, is the living portion of the wheat kernel. Under proper conditions, the germ grows into a new wheat plant. The germ is relatively high in protein (primarily enzymes), lipids (fat), and ash. If the germ is left in the fl our during the milling process, it quickly becomes rancid. Part of the germ can be recovered during milling; it is stabilized and sold as a specialized food ingredient. The remainder of the germ is sold as animal feed. The largest part of the wheat kernel is the endosperm. It supplies energy to the new plant as it grows from an embryo. The endosperm is made up of starch granules in a protein matrix. The protein matrix is made up of gluten-forming proteins. The endosperm also contains a small amount of lipids and non-starch polysaccharides. The non-starch polysaccharides are primarily arabinoxylans and are the major constituents of the endosperm cell walls. The endosperm’s aleurone layer is free of both starch and gluten, and is made up of protein bodies instead of a protein matrix which also contain, lipids, a high concentration of minerals (ash), and many phytonutrients. © Copyright AIB International May not be reproduced without written permission. 5 Function of Ingredients in Bread Production BAKING SCIENCE AND TECHNOLOGY Bread flour Milled from hard wheat usually containing more than 10.5% protein. These flours contain proteins that produce a strong gluten when mixed into a dough, which, along with high absorption and good tolerance, makes the flours suitable for making yeast-leavened products. High gluten flour Milled from hard wheat, usually spring wheat. Generally used in the manufacture of hearth breads. Usually 12.5-14% protein. Pastry flour Low protein (less than 10%) flour milled from soft wheat, with ash less than 0.50% and little mixing tolerance. Pastry flour is used to produce many products, including low-ratio cakes, piecrusts, and cookies. Cake flour A highly refined (low ash) flour milled from soft wheat, having fine particle size. Treated with chlorine for bleaching (lowers pH), in the US. Used in high-ratio batter cakes. All-purpose flour Also known as hotel and restaurant flour. Usually made from low protein hard red winter wheat or a blend of hard winter and soft winter wheats. Is designed to serve general household use for all bakery foods, therefore, it is not the ideal flour for any specific bakery food. Wheat fl our’s gluten-forming protein matrix makes it ideal for the production of many baked goods. When wheat fl our is mixed with water, the gluten matrix is developed, and a structure-forming network is created. Once this network is heated in an oven, the structure is set. Vital Wheat gluten Wheat gluten can be extracted from fl our and sold as a separate ingredient, “vital wheat gluten”. Vital wheat gluten is sold in a dry fl our form and is added to formulas to help strengthen weak fl ours or to create extra loaf volume. A 1% addition of vital wheat gluten will increase the fl our protein content by 0.6% and absorption by 1.5%.