Use of Dairy Ingredients in the Baking Industry

#227 - Use of Dairy Ingredients

BULLETIN No. 227 - JUNE, 1993

Use of Dairy Ingredients in the Baking Industry

By Jack H. Barcinski, Richardson, Texas

Copyright 1993 by the American Society of Bakery Engineers

INTRODUCTION

Milk and other dairy products have been used by bakers for centuries. Spurred by technology and economics, the variety of dairy ingredients has greatly increased in recent years, making selection more complicated and the understanding of product composition and functionality essential.

HISTORY

The classic dairy-based ingredients used by the baking industry were liquid whole milk, skim milk, liquid buttermilk and butter. The liquid products were replaced by nonfat dry milk and dry buttermilk: produced by the roller process which was, in turn, replaced by spray drying.

Although these changes have benefited delivery costs, convenience, and storage life of these ingredients, the current spray dried products do not contain some of the flavor benefits or absorption characteristics of their predecessors.

Recently, fresh liquid buttermilk (sometimes cultured) is once again being used in the production of biscuits which is increasing greatly throughout the United States. It is reported that dough and finished biscuits characteristics are demonstrably improved by use of fresh buttermilk: which has not been dried nor condensed.

Butter use has declined through the years as better shortenings and margarines have been developed. However, butter still delivers unique flavor and mouth feel to many pastry products and is used as the topping on the popular "spilt top" breads.

The use of nonfat dry milk and dry buttermilk: in bakery products has also declined substantially over the past thirty years. The main reasons for this trend are:

A. Costs. Even before the extremely high prices of recent years with nonfat dry milk rising to $1.40 per lb., the relative cost of these ingredients has risen steadily since the early 1950s when nonfat dry milk reached the alarming price of $ .30 per lb.!! It was at that point in time that the first whey/soya blends were offered to bakers at $ .07 per lb.

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#227 - Use of Dairy Ingredients

B. Ingredient Processing. As already mentioned, dairy ingredients manufactured by the spray drying process do not offer the absorption and other benefits of the older roller (drum) dried products.

C. Bread Processing. Formula use of nonfat dry milk in the temporarily popular continuous mix bread process aggravated the problem of sidewall strength of continuous mix bread products. When continuous mix plants reverted to the traditional sponge/dough process, nonfat dry milk: was not put back into the formulas.

PRODUCTS

Key dry dairy ingredients used by the baking industry are:

Nonfat dry milk: - high heat and/or low heat Buttermilk: powder - high heat and/or low heat Buttermilk: product Cultured and/or acid buttermilk: Dried whey Modified whey product Caseinates Lactose Blends

Both nonfat dry milk and dry buttermilk: have grading requirements which are of great importance to the dairy industry. For example, manufacturers of Grade A ice cream and frozen desserts must use Grade A dairy ingredients which, in turn, can only be produced at USDA Grade A "approved" plants under Grade A conditions.

The baker can be totally satisfied with "Extra Grade" which may or may not meet all of the "Grade A" criteria. These deal primarily with USDA permits and do not achieve any "tighter" or "better" specifications from the baker's viewpoint.

Use of "Standard" or lower grades of nonfat dry milk: or buttermilk powder in baked goods is not recommended.

As we discuss these ingredients, it is important to defme the contribution to baked foods made by the main components of these ingredients. These can be grouped as follows:

Dairy Proteins: Improve absorption (nonfat dry milk: and dry buttermilk can hold an equal weight of water in a dough) and machinability during processing.

Improve texture and shelf life of finished bread and rolls and the aeration of cakes.

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Milk proteins are nutritionally valuable because they contain ratios of essential aminoacids very suitable for human requirements.

Dairy Sugars: Lactose is the preponderant sugar in dairy products. It is significantly less sweet than sucrose or even dextrose, but it contributes dramatically to crust color formation and it is not fermented by baker's yeast. Thus, it is totally available in yeast raised baked products for crust color formation as well as contribution to flavor, sweetness and shelf life.

Because of the above, shorter bake times are possible when using dairy ingredients.

Dairy Fats: Except in the case of high level usage of butter in sweet goods and pastries, fats from various shortenings can perform better in baked foods at a lower cost.

Minerals: Nonfat dry milk: and dry buttermilk: contain significant levels of calcium (about 1.3%) 50 important to good nutrition.

Although other minerals are present in dairy ingredients, they do not enhance the nutritional value of baked foods. In fact, such minerals and high levels of ash can negatively affect processing and quality of breads and cakes - resulting in dull color and lower volume.

General Comments: Dairy products are powerful buffers and their use in yeast-raised products can necessitate longer mix times unless other formula changes are made.

Keeping the above comments in mind, let us focus on the dairy ingredients under discussion:

Nonfat Dry Milk: is obtained by the removal of water from pasteurized skim milk:. Although "low heat" nonfat dry milk: is best for flavor and aerating properties in cakes, filling/icing and similar applications, the bread and sweet goods baker must insist on "high heat" product (more on this later).

Dry Buttermilk Powder is obtained by drying liquid buttermilk: which is derived from the churning of butter then pasteurized prior to condensing.

Dry Buttermilk: Powder must have a protein content of not less than 30%. It may not contain, nor be derived from, nonfat dry milk:, dry whey or products other than buttermilk, and contains no added preservative, neutralizing agent or other chemical.

Dry Buttermilk: Product has the same-definitions as dry buttermilk powder except that its protein content may be less than 30%. Thus, liquid derived from the processing of whey may be used in buttermilk: product There is little dry buttermilk product used in the baking industry.

The government and the dairy industry have made little effort to define the types and variations of

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buttermilk: and have made such definitions simpler for the dairy processor, but not for the baker. For example, most buttermilk sold at retail to the consumer is made from reconstituted nonfat dry milk: which is acidified or cultured, then thickened by the use of gums and emulsifiers.

Heat Treatment: As mentioned above, the manufacturer of yeast-raised baked foods, especially bread, must use nonfat dry milk or dry buttermilk which has been carefully heat treated during the condensing and drying process.

This heat process denatures most of the soluble whey proteins which, if not so treated, can severely hamper gluten development and result in slack doughs which do not proof satisfactorily.

Since high heat treatment requires more careful time and temperature control both the dairy and the subsequent dryer must have good control of their operations. For example, milk: intended for high heat nonfat dry milk is held for about thirty minutes at 180-190 degrees F versus low heat pasteurization of under two minutes at 162 degrees F.

Many bread bakers have had the unfortunate experience of receiving inadequately heat processed nonfat dry milk: and dry buttermilk:, and most now demand guaranteed high heat materials.

The adequacy of heat treatment is measured by the amount of whey protein nitrogen. This is commonly called "W.P.N."

In the case of nonfat dry milk:, the USDA defines high heat nonfat dry milk: as having a W.P.N. of 1.5 ml/gram or less and most dairy ingredient suppliers address this through use of the "W.P.N." test. There has been much controversy about the application of the same methodology to test buttermilk: powder and there is no standard definition for high heat buttermilk: powder.

It is suggested that all bakers insist their suppliers test, or have tested, the buttermilk powder by a laboratory capable of producing consistent W.P.N. results and guarantee that the buttermilk powder not contain any whey components.

Finally, it is important to point out that high heat treatment does nothing for the ingredients involved, except to denature protein and improve absorption. Many users classically specify "high heat" when, in reality, they do not require this and receive ingredients which may have a "burnt milk:" flavor note or even scorched particles for no purpose. For example, foaming and whipping properties of nonfat dry milk are greatly harmed by high heat treatment.

The deleterious effect of inadequate heat treatment of nonfat dry milk: or dry buttermilk: is mostly encountered when these ingredients are used in yeast-raised goods at levels of 3% and higher (based on flour weight). Bakers producing "Standard of Identity" milk bread or buttermilk bread or other premium breads and sweet goods are most vulnerable.

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It is good practice to raise oxidation levels when using nonfat dry milk: or buttermilk: powder to further offset these problems.

Cultured Buttermilk: As done by nature years ago (before pasteurization), the milk: obtained from the churning of butter can be inoculated with bacteria which convert some of the lactose to lactic acid, thus giving the resulting material the tangy flavor associated with buttermilk.

Acid Buttermilk: Very similar to the cultured product except that instead of the culture, lactic acid it-self is added to the fresh buttermilk: before drying.

Both cultured and acid buttermilk: powders find use in biscuit production and also in English muffin products where the acidity assists in achieving a desirable open grain.

Sweet Cream Buttermilk: When no bacteria or acid is added, the buttermilk: is usually called "Sweet Cream" and often so designated by suppliers and customers. However, current USDA definitions have dropped this nomenclature. Bakers should include these words in the specifications to emphasize their need for the "real thing,"

Dried Whey: Dried whey has been the most widely used "milk: replacer" in recent decades. It has frequently been used as a blend in conjunction with a soya component in order to improve absorption and protein content (See Composition Chart No. I).

The major component of dried whey is lactose which contributes to crust color of breads and rolls. Bakers purchasing dried whey should specify "sweet dairy whey" and also demand the "nonhygroscopic" type which has been produced and stored under controlled conditions.

Sweet Dairy Whey: The liquid obtained from milk: or cream during cheese making. When this liquid comes from cheddar, SwIss, and certain other cheeses, the lactose is not converted to lactic acid and thus the term "sweet." No chemicals or preservatives are added and the material is spray dried for commercial use.

Acid Whey: Acid whey is obtained from cheese making where acidification occurs (i.e., cottage cheese) and significant amount of lactose has been converted to lactic acid. It can be used similarly to acid or cultured buttermilk.

Other products from whey are:

Whey Protein Concentrate (35% protein) - Useful as a stabilizer in whipped toppings and fillings to help shelf life and improve freeze/thaw tolerance.

Whey Permeate (82-84% lactose) - Liquid obtained from whey protein concentrate production which is then spray dried. When properly processed and handled, it is an economical source of lactose.

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