Rolling Out Quality Pies and Turnovers

October 2001

The phrase “easy as pie” stretches the truth, since many bakers would argue that obtaining just the right flaky crust isn’t all that simple. One could dispute that instead, it’s rather easy to select the wrong type of flour and create a tough pie crust. It’s also rather easy to ruin a pie crust through overmixing. And for those who think all that’s necessary are some sugared apple slices, it’s certainly easy to come up with the wrong assortment of ingredients to create the filling. Perhaps the phrase should be reworded to read, “easy to mess-up as pie.”

Creating pies and related products, such as turnovers, on an industrial scale, however, is not impossible. After all, many companies have been doing it successfully for years. With some thought to ingredient selection and taking care to optimize process equipment, product designers can create pies and turnovers that bring back homey memories to consumers.

Deconstructing pies and turnovers
Around the world, most cultures feature some type of food where a piece of dough is wrapped around a filling. In the United States, the traditional pie is baked in a round pan lined with a pastry dough and may or may not be topped with an additional crust.

Turnovers, for the most part, are nothing more than handheld pies. This category includes most any filled product surrounded by a single piece of folded dough. The fried fruit pies sold in the snack cake section, for example, technically are fried turnovers.

Worldwide, crusts for pies and turnovers may take many forms, from simple noodle-like doughs to highly laminated puff pastry doughs. Pie dough may even be a yeast-raised dough — such as that used for pizza or bread. The potential fillings are equally diverse, embracing everything from meats, cheeses and vegetables to fruits, puddings and custards. This article will confine its discussion to the forms of pies and turnovers most commonly found in the United States that are made with pastry dough holding a fruit or crème filling.

Structure of the crust
Pie crust typically takes one of two forms: crumb crusts made from cookie or graham cracker crumbs, or the traditional rolled pastry crust. A crumb crust is pretty simple from a formulation perspective. Finely crushed cookie or cracker crumbs are blended with oil or melted shortening with, perhaps, some added sugar or flavoring ingredients. This mass then is fed into a shell-making device that deposits the mixture into pie pans and compresses it with a form to the proper thickness. Pastry pie crusts, on the other hand, present more of a challenge.

Pastry crust is primarily flour, shortening and water. Although other ingredients — such as sugar, flavorings or eggs — may be added, the primary structure is based upon those three simple ingredients. Among those ingredients, however, lies a great deal of variability that will affect the crust’s desired outcome: a dough that’s cohesive enough to be rolled during forming, yet able to retain a flaky structure with tender eating qualities once baked.

The first step to a successful crust is the selection of the correct flour. Wheat flour can form a flexible, extensible dough when its protein content is developed into gluten through the addition of water and mixing. Wheat classification will largely determine how much protein a given flour will contain and, consequently, its suitability for pie crust. Wheat is classified by three major categories: growing season, bran color and kernel hardness.

Farmers grow wheat in two distinct growing seasons. Winter wheat is planted in the fall, lies dormant during the winter months and is harvested during late spring to early summer. Flour milled from this crop contains between 10% and 12% protein and has medium gluten strength. Planted in the spring and harvested during late summer, spring wheat produces flour that contains between 12% and 14% protein and has high gluten strength.

Wheat kernels have a protective outer coating that makes up the bran. The bran color determines this next wheat classification, which is either red or white.

The final classification for wheat is kernel hardness. This will have the greatest effect on the resulting flour’s baking properties. Hard wheat flours have a medium to high protein content and stronger gluten-forming proteins than soft wheat. Consequently, hard wheat flours tend to be ideally suited for yeast-raised products that depend on gluten strength to retain leavening gasses. Soft wheat flours are lower in protein and gluten strength and are more commonly found in pastries and chemically leavened products.

Although flour milled from soft red winter and soft white wheat is used for most cakes, crackers, cookies and pastries, pie crusts have some unique requirements. A high-gluten, hard wheat flour generally contains about 12.0% to 13.0% protein. The extra strength and elasticity it provides may make it appear to be the flour of choice for pie dough. Unfortunately, too much gluten development will make the dough too difficult to roll into the required thin sheets and the resulting pie crust will be tough and chewy. A pastry flour milled from soft wheat offers a protein range of between 8.5% and 10.0% and will produce a more tender crust. Unfortunately, such low protein levels also will yield a pie dough that isn’t cohesive enough to be formed mechanically.

The solution lies in using pie/pastry flour that is a blend of hard and soft wheat flour with a protein content no higher than 10.0%. Some flour suppliers also offer lower-protein flours that contain all hard wheat from a winter crop. Since bleaching tends to strengthen the gluten, select a flour that is unbleached or treated in any other fashion.
Although the protein content of flour is a good guideline, also make sure to check for the flour’s protein quality as well as quantity. It may be the case — due to seasonal fluctuations, etc. — that a flour of a higher gluten content actually is suitable for your formula.

Protein quality can be measured indirectly with a dough-testing instrument such as the Farinograph, which measures the resistance of a flour-and-water dough to mechanical mixing and records this resistance graphically as a curve. This curve’s shape offers some insight into the flour’s dough strength, mixing tolerance and absorption characteristics. Farinograph curves, however, aren’t perfect since interpretation often is subjective. Consequently, a flour’s protein quality should be affirmed with an actual bake test. Use protein content and Farinograph results to guide your flour sampling, but use a bake-test to make your final selection. Even with a designated supplier, some adjustments may be necessary for each subsequent wheat crop year.

Foundation for flakiness
The next major ingredient in the dough is a plastic fat, known as shortening. This helps to tenderize pie crust by inhibiting gluten development. More importantly, shortening works with the flour to create a pie crust’s characteristic flakiness. The fat acts as a spacer in between dough layers. The heat of baking first sets the flour’s starches around the fat, then melts the shortening so it is absorbed by the now-set dough structure. This leaves many layered empty spaces in the crust structure, which are perceived by the consumer as flakiness.

Unlike a Danish pastry where the shortening is spread between laminated dough layers, for traditional pie-crust manufacture, shortening is added to the mixer and lightly mixed with dry flour to form uneven lumps. Mixing the shortening into lumps runs contrary to many other bakery foods in which the flour is added to the mixer after it already has creamed the shortening with other ingredients. Also contrary to other bakery foods, the mixing action must include cutting action to effectively break the shortening into lumps, rather than creaming it into the flour. The mixing time required to achieve this balance will be directly affected by the fat’s specifications.

To create an effective flake, the shortening must offer certain properties. The first, the solid fat index (SFI), refers to the amount of shortening in the solid state at a series of temperatures. For cocoa butters and fats designed for confectionery coatings, the curve will have a steep slope for a fast meltaway. For pie crust, the SFI curve must have a gentler slope. The fat should melt fast enough to avoid a greasy mouthfeel, yet slowly enough so that it retains the flaked structure of the crust during baking.

From a manufacturing perspective, pie crust shortening also should be soft enough so that it can be broken into pieces easily, yet brittle enough so that these breaks are clean and yield many small pieces in a relatively short mixing time. To balance out the mouthfeel requirements with the manufacturing needs, pie shortenings often are chilled prior to being added to the mixer.

Other dough options
Although flour and shortening comprise the majority of a pastry crust, some product developers may choose to add other ingredients, such as sugar or other sweeteners. In some situations, real butter or a butter flavor may be desirable. Don’t forget that, as a fat, butter used for flavoring purposes will affect the properties of the dough and the finished crust.

Other ingredients, such as emulsifiers, may be added to the dough to lend flexibility and machineability to the dough. Whey or lactose, for example, may be added to pie crusts at around 2% to 3% or 6% to 8%, respectively, based upon flour weight. By aiding shortening emulsification, these ingredients may help reduce overall shortening levels without causing detrimental effects to the crust’s texture. They also may improve the crust’s final color and flavor by providing added reducing sugar and protein that takes part in the Maillard reaction.

Bringing it all together
With the flour and shortening selected, how the dough is put together will be the key variable affecting crust quality. Although many bakery products require skillful balancing of ingredient characteristics and process parameters, it is especially true for pie crusts.

Pie crust is best kept cool to preserve shortening lumps. Generally, dough temperature will be most easily controlled by adjusting the starting temperature of the shortening and water. In some locations, flour from the bulk system may be so warm at certain times of the year that it’s impossible to get the shortening and water cool enough to compensate. Here, it may be necessary to either use a jacketed mixer or add a little dry ice to the mixer to cool the flour down once it’s scaled and loaded.

Add the shortening to the flour (and other dry ingredients, if any) and process in the mixer. Precisely determine this mixing time in order to optimize the size of the shortening lumps. For the second mixing stage, introduce the water and other liquid ingredients. The amount of liquid should be sufficient to bring together a cohesive dough, but not enough to cause excess gluten development. For the same reason, determine the proper mixing time for this stage, as well.

After mixing, the dough may require a certain amount of floor time to help moisten all of the flour particles. Floor time can be a useful tool as it can help minimize mixing time while enhancing dough cohesiveness. Make sure, however, that the dough isn’t held in a too-warm environment. This may melt the fat and decrease flakiness. Subsequent dough handling also may be detrimental to crust quality. Adjust forming equipment to make sure the crust is sheeted in the quickest, gentlest way possible to avoid further gluten development. Because excess handling also may overdevelop gluten, minimize the amount of rework used in the formula.

Because both ingredient characteristics and process variables directly affect pie-crust quality, it should come as no surprise that changes to either one may either cause — or eliminate — undesirable crust traits.
If the crust lacks flake, it usually means that the shortening is cut in too finely. Make sure all of the ingredients are at the proper starting temperature and all process times are being executed properly so that the shortening is cut into in larger pieces. If the problem is consistent despite process adjustments, it may be necessary to reformulate with a fat that has a higher SFI profile.

Crumbly crusts that are too tender might be caused by too little gluten formation in the dough. From the several possible solutions, first try reducing the initial mix time for the shortening and flour. Other possibilities include cooling the shortening to a lower temperature prior to the initial mix, increasing the amount of water, or increasing the mix time after the liquid is added.

Tough crusts generally are caused by too much gluten development. If this type of problem occurs consistently after optimizing mix times, consider reformulating with a flour that contains less protein. This may mean selecting a softer flour variety, or a blended flour that contains a higher ratio of soft wheat to hard wheat. Another possibility is to increase the shortening content.

If the tough crusts occur with no apparent raw material changes, it could be a process variable. For example, inadvertently decreasing the amount of time the shortening is cut into the flour by the mixer and subsequently overmixing after the liquids are added may yield a tough crust. Make sure production staff adheres to proper mix times so that the shortening is properly cut into the flour and subsequent mixing only works the dough to the proper degree of cohesiveness necessary for machining. Another possibility is that the shortening isn’t being cut thoroughly enough into the flour because it is too cold. Check to make sure the shortening’s holding temperature hasn’t been altered.

If the pie’s crust edges lose shape or fall, the shortening may be softening before the crust sets. Here, you might try increasing the oven temperature, or adjusting the crust make-up procedure so that the dough is cooler before baking. Another potential cause for losing shape is either too little flour or too much water in the crust formula.
If the crust shrinks excessively — particularly noticeable when baking empty shells — it could be because the equipment is stretching dough prior to panning. Adjust the sheeting equipment to minimize this stretching.

Soggy bottom crust often occurs when the oven temperature is too low or baking time too short. Increasing one and/or the other may solve the problem. Another possibility is that the filling is too hot when placed into the shell or is added too soon before the baking process.

From the outside in
One of the particular challenges with pies is that not only does the product designer have to create the ideal crust, but they must pair it with the perfect filling, too. Dessert pie fillings fall into two general categories, fruit and crème, (though something on the order of a pecan pie might not truly fit neatly in either category). Each type presents its own unique challenges.
Fruit fillings for pies may either be purchased in a ready-to-use form, or manufactured onsite. An individual company’s situation will determine which route to choose.

Premade fillings offer the biggest advantage to companies just expanding into pie manufacturing. They won’t need to invest in equipment to manufacture the filling. Nor will they need to worry about gaining the knowledge and experience to do it properly. “Pie manufacturing can be pretty simple if all you’re doing is forming crusts and depositing premade fillings,” says Scott Summers, technical director, Tree Top, Inc., Ingredient Division, Selah, WA. “Many manufacturers are simply set up only to bake pies and freeze them.”

Another advantage to seeking out a filling manufacturer, according to Summers, is simply that many such suppliers exist and produce a variety of high-quality fillings. “They’re set up to make fillings for packing into 55-gal. drums,” says Summers. “They already have the knowledge and some of them have great filling formulas.”

On the other hand, an established pie baker already may have the same capabilities in place making an in-house job more appropriate. “It often comes down to economics when deciding to make fillings in-house,” says Summers. “Any time you cut a middleman out, you save money.”

Sometimes, the geographical relationship to the raw materials can be a factor. After all, if the production facility is in the middle of apple country, it makes more sense to process the filling onsite. Otherwise, the pie manufacturer ends up paying a premium to cover the supplier’s cost to ship the apples to their production facility and the finished fillings back.

Whether selecting a premade filling or creating one in-house, knowing how a filling is put together is useful knowledge. Fruit-pie fillings all generally start with the same primary ingredients: some type of fruit, sweeteners, stabilizers and acidulants. Flavors and colors also may be added to enhance those coming from the fruit; antimicrobials also might be required. Filling moisture can vary depending on the end use. Fresh-distributed products need lower moisture to minimize microbial activity and excessive moisture migration from the filling to the crust. Freezing, and often the addition of stabilizers, help tie up the available water in the filling, so frozen pies can be formulated with water levels similar to that of a homemade pie.

Picking the fruit
The actual fruit content offers significant flexibility. Many varieties of fruit make suitable pie fillings and the actual fruit content may vary over a wide range. The trick is to balance ingredient costs with consumer desires for significant fruit identity.

Price invariably limits the amount of fruit that a product designer can put into a filling. In poor crop years, the cost of the same fruit will shoot up. Sometimes, the only solution is to reduce the fruit levels and compensate by adding flavor and color ingredients. Using lower levels of fruit solids also may make the filling formula more dependent on additional ingredients such as starches.

When required to use lower quantities of fruit, one way to improve fruit identity is by specifying larger pieces. Processing the filling with larger fruit pieces, however, often requires longer heating and mixing periods, and may cause some of the carefully won piece identity to be lost. Remember that using larger fruit pieces is best with a higher quality, firmer fruit. As far as whether to choose fresh, frozen or some other form of fruit, pies are, fortunately, not too fussy in this area.

Fresh. If at all feasible to use, fresh fruit offers the advantages of excellent flavor and good visual appeal. Different fruits do, however, have different seasons. Also, the pie production facility may be far removed from where the source fruit is grown. Consequently, many manufacturers choose a form of frozen fruit.

Frozen. Frozen fruit is available in IQF (individually quick frozen) or solid-pack forms, with IQF fruit tending to more closely resemble fresh fruit. Frozen very quickly without added sugar, water in IQF fruits form small ice crystals. This minimizes the ice-crystal damage to the structure of the fruit.

Solid-pack frozen fruit is filled into containers and frozen in bulk. Although fruit sometimes is frozen in its own juice or in the juice of a different fruit, the fruit supplier often adds sugar or corn syrup. The amount of sugar solid-pack fruit contains is designated by the number +1. This refers to the ratio of fruit to added sugar. Packing 5+1 cherries, for example, means five parts cherries to one part sugar.

Although the manufacturer will have to deal with frozen transport and frozen storage when using either solid pack or IQF fruit, each offers quality advantages. IQF fruit may even be used as a process aid. “Companies that make premade fillings need to find a way to bring the temperature down quickly without going through a cooling stage when packing into 55-gal. drums,” says Summers. “Some people use IQF fruits to bring the temperature down.”

This can help when working with strawberries, for example, or other soft fruits that are very temperature-sensitive and will lose nearly all of their piece identity if cooked long enough to gelatinize the filling’s starch. Cooking up the starch without the strawberries, then adding them toward the end helps cool the system down and expose the berries to only minimal cooking and mixing shear.

Other than such special cases, IQF fruit — like solid-pack fruit — should be thawed under refrigeration before assembling the filling. If the fruit is thawed at room temperature, the center may remain frozen while the fruit near the outside of the container or pallet may undergo microbial deterioration, browning and textural loss. Keep in mind that refrigerated thawing may take more than one week if the fruit is packed in large bulk containers or drums.

“One of the intrinsic problems with solid pack is you have to temper the fruit,” says Summers. “Plus, there is a school of thought that there is more damage to slow freezing than with quick freezing.”

Hot pack. Another industrial form of fruit is that which is heat-treated to preserve it during distribution. These processes include canning, aseptic processing and pasteurization. Prior to heating, the fruit is packed in liquid to enhance heat transfer.

This liquid may be a light or heavy sucrose syrup, fruit juice or water. Adding sugar raises the solids and extends the shelf life by acting as a preservative. It also helps to increase the solids of the fruit itself. When this fruit is used to make a filling, it reduces the time required for the solids of the finished filling to reach equilibrium. It also affects the specific gravity, which aids in fruit dispersion.

Depending on the time and amount of heat, hot pack fruit may suffer degradation of color, flavor, texture and nutritional value. Heat treatment does, however, offer a significant benefit in that it will deactivate the proteolytic enzymes in pineapple and papaya.

Dehydration and infusion. Fruit fillings also can be made with dried fruits. With the exception of fragile-skinned fruit, such as citrus or certain berries, most fruits can be dehydrated successfully. Drying reduces the moisture level, which helps prevent microbial or enzymatic deterioration and makes the fruit more economical to ship and store than other forms. Dried fruit also may be coated with oil, corn syrup solids or starch to prevent sticking and keep the product free-flowing.

To guard against enzymatic browning — particularly with lighter-colored fruit — and the loss of carotene and ascorbic acid, dried fruits often are treated with sulfites. Because of consumer concerns, suppliers may use a sulfite alternative, such as ascorbic acid or citric acid. Some manufacturers, however, still use sulfites because their tests show that once sulfite-processed apples are further processed, virtually all the sulfites cook off.

Evaporated apples contain approximately 22% to 26% moisture. This is much too low to expect that the apple pieces will pick up sufficient moisture when cooked into a filling. Therefore, rehydrate dried fruit prior to using it for a filling. Whether hot or cold water is used will depend on the absorption properties of the fruit. Dried fruit with high absorption rates may turn too soft and mushy if rehydrated with hot water. Cold water is yet another way to minimize fruit’s heat exposure.

Sweet selection
Sugars make up a significant portion of fruit-based pie fillings. In fact, one of the major specifications for these products is Brix. The fruit, sweeteners added during freezing/packing, and sugar used in the formulation all contribute to the filling’s final Brix. When using fresh fruit, keep in mind that the amount of sugars in the fruit will vary depending on the degree of maturity and the growing conditions. Processed fruit sources usually will be standardized by the supplier.

As with choosing the fruit, the first consideration for selecting sweeteners is cost. Corn syrups not only tend to be less expensive than sucrose, they often are easier to use because they can be pumped using a bulk system. Because they have higher levels of monosaccharides, corn sweeteners also depress the freezing point of a filling. This could be a useful feature for a fully baked frozen pie that is soft and ready-to-eat with less thawing time.

High-intensity sweeteners may be useful in creating lower-calorie or sugar-free products. Make sure, however, to compensate for the lost solids. Otherwise the filling will not have the correct body. Polyols, such as sorbitol, maltitol and polydextrose, can be added to replace solids lost when sugar is removed. Because many of these products have humectant qualities, they will soften the texture and hold on to moisture, a helpful quality when the filling is baked.

Keeping it stable
Although consumers may wish it otherwise, pie fillings often require more than fruit and sugar to hold up under manufacturing and distribution. The product designer must address several issues related to the filling to assure adequate performance and shelf life.
Viscosity. Proper viscosity development not only is an important part of the finished-product texture, it also influences the filling’s processability and, in the case of a premade filling, its storage stability prior to being used for pies.

Moisture control. No one likes a soggy crust. The filling should be designed to maintain its integrity from that of the crust. Fruit that has too much (or too little) moisture causes a moisture imbalance in the filling that leads to boil-out. Stabilizers help control this. Also, not all consumers will finish an entire pie in a single sitting. Syneresis that occurs after the pie has been partially eaten should be minimized.

Effects of freezing/thawing. Whether the pie is to be frozen for later consumer bake-off, or distributed as a frozen, baked product, avoiding ice-crystal formation and ensuring freeze/ thaw stability are formulation priorities.

Acidity. Although the addition of acid contributes to microbial control, acidulants also contribute flavor and may be required for optimum performance from certain hydrocolloids.
Other organoleptic properties. Between initial cooking, baking, freezing and thawing, a filling’s texture, flavor and appearance may undergo some changes.

Fortunately, both formula and ingredient solutions exist to confront these product-quality demands.

A fruit filling usually will be acidified to a pH of 4.5 or lower for microbial control. With a higher pH product, the microorganisms must be controlled with a water activity (Aw) below 0.85. This correlates to a soluble-solids content of about 70% or higher. Pie filling usually has a solids level of approximately 30%, so premade versions typically are acidified. The completed pie must either be frozen, or distributed as a short-shelf-life fresh product. In the frozen state, a pie either may be fully baked (requiring the consumer only to thaw them out) or raw (for the consumer to bake-off).

Most premade fillings will be formulated with a high pH and as low Aw as possible. In some cases, bulk aseptic packaging is used to reduce the risk of microbial spoilage.

Food acids vary in their ability to lower pH, depending on the molecular configuration. The most commonly used acidulant is citric acid. It creates a sharp, clean bite that quickly dissipates. Other acids may be more suitable if a particular flavor is desired — such as malic acid in apple filling. Malic acid is found naturally in fruits. It has slightly more acid flavor than citric acid, but it builds up and diminishes. Lactic acid imparts a mild acid flavor with some lingering effects, and does not have a tendency to overpower weaker flavors. The acid taste lingers with fumaric acid and its flavor in solution is much stronger than that of citric. Tartaric acid generates a strong fruit acid flavor that is slightly stronger than citric acid. Ascorbic acid can reduce browning in light-colored fruits, such as banana or peach, but it is fairly expensive compared with other acids. Phosphoric acid has a harsh, sour acidity, and is generally not used with fruit.

Combining a weak acid and a salt, such as citric acid and sodium citrate, controls the amount of free hydrogen ions and buffers the pH. This helps provide protection from pH-dependent effects like color or flavor changes.

Slicing up texturizers
Pie fillings require a certain amount of viscosity to maintain their consumer appeal. The same ingredients that contribute this texture also are important for moisture control: starch and/or hydrocolloids.
The most common thickener for pie fillings is modified corn starch. Typical use levels range from 3% to 7%, depending on the desired viscosity, and texture in the finished filling.

When cross-linked, corn starch resists breakdown due to the shear of mixing and other physical processes. Another benefit of cross-linked starches is that they have improved performance in acidic systems, such as pie filling. Unfortunately, cross-linked starches require cooking to a high gelatinization temperature — not the best thing for heat-sensitive fruit. Substituted, or stabilized, starches provide freeze/thaw and acid stability with lower gelatinization temperatures. Today, product designers have additional options, such as native corn starches that have enhanced functionality. Ordinary native starches readily break down, but these newer ingredients have physical modifications that alter the starch granule to enhance its performance.

The product designer must balance the positive and negative aspects of different starches. In general, a cook-up starch will offer better long-term stability and better water-holding capacity. In pie fillings, however, the sugar and high solids content may compete for available water and make gelatinization difficult. A pregelatinized starch may help in this situation, but to assure long-term stability, adjust the process so that most of the sugar or solids are withheld from the process vessel until after the starch is cooked out. After the proper viscosity is built, add these ingredients to the desired solids level.

Not only do pie fillings have significant solids contents, they also are acidic — which further alters unmodified starch performance. Early in the cooking process, the acid will actually help with gelatinization and swelling of the starch granule. With continued heating, however, the acid will hydrolyze the starch’s glucosidic bonds, causing the starch’s molecular structure to fail. The starch granule then breaks into useless, low-molecular weight polysaccharide fractions.

Sometimes, a starch blend, or a blend with hydrocolloids may prove to be the solution. After all, some hydrocolloids, such as pectin, perform more effectively in acidic environments. This is, however, not such a simple solution. For example, methylcellulose and hydroxypropyl methylcellulose work over a wide pH range, while high methoxyl (HM) pectins only gel when the pH is between 2.5 and 3.8 and only when solids range from 55% to 85%. Acid conditions cause some hydrocolloids to form a precipitate or prevent adequate hydration of the molecule and may also affect their heat tolerance.

How the stabilizer system is incorporated directly will affect performance. Proper dispersion of the stabilizer prevents lumping. Some gums, such as microcrystalline cellulose, require high shear for proper dispersal. Constant agitation must be applied until full solubilization occurs or the stabilizer may settle out. Starches are best predispersed in water to form a slurry. Gums, on the other hand, are best premixed into a dry ingredient, such as sugar.

Color me flavorful
Fruit fillings require heat for processing. In addition, they are acidic. Both the high heat and acidity have the potential to cause deterioration of both the color and flavor of the fruit. This situation is all the more unfortunate since the filling will be put into a pastry and will require more of a flavor impact to balance with the flavor of the crust.

Before you start calling up the flavor and color suppliers, first recheck your fruit source. Make sure that what you have is suitably colorful and flavorful from the start. Only then should you start working to enhance the flavor and color of the filling with additional ingredients. Make sure to test the filling in a finished pie through an entire course of freezing and thawing, too. Flavors are just as likely to fade from extended freezer storage as they are from heat exposure.

Once you have selected all the ingredients, it’s time to put the filling together. Generally, this can be as simple as heating up the water, acid, sweeteners and starch until the starch has gelatinized, then add the fruit, flavors and colors and bring everything up to an appropriate temperature for the filling’s subsequent handling and any potential microbial concerns. (Most likely, a manufacturer making a filling to be used immediately will not have the same temperature requirements as a filling supplier.)

Remember, however, that some of the ingredients may conflict with each other. These conflicts are overcome with creative ingredient addition. Start again by cooking the water, acid, sweeteners and starch until the starch has gelatinized. This time, however, hold back some or all of the sweeteners to make gelatinization easier for the starch. Once gelatinization is achieved, then add the withheld sweeteners, and if in dry form, preblend with any gums that may be in the formula. Next, add the fruit and bring the batch just about to the required temperature. Now, add the colors and flavors and confirm the temperature.
At this point, just buying the filling is looking pretty good. In fact, you might be asking, “Why can’t I just put the filling ingredients into the shell and let the baking process cook everything out like I do at home?”

Guess what? Many companies make their pies exactly that way. Most often this approach is taken for more upscale pies. As previously discussed, heat has a negative effect on flavor. Consequently, a typical frozen pie is going to expose its filling to heat on several occasions. First, the fruit might be heated when bulk packed after harvest. Next the fruit is heated when made into a filling. Finally, the fruit is again exposed to heat when the pie is baked.

“You always work under the assumption that the pie has to be baked,” says Summers. “At some point — either in the baking process or the filling process — you have to do some thermal processing. Any time you can minimize it, you’re better off.”

The idea is, if you can reduce the number of heat exposures, you’ll improve the pie’s fruit flavor. First, the fruit — IQF apples, for example — is deposited into the shell. Next, any spices, starches or flavors are added before the pie is given its top crust. Some companies will dry-blend the apples and other ingredients together first, then put them into the shell. “When the pie is baked, the moisture from the fruit comes out and it actually makes the pie filling in the crust,” says Summers. “This precipitates minimal processing on the fruit because the only heat is the final bake — which you can’t get around anyway.”
Summers is certain that this method is used in pies for consumer bake-off as well as for small, hand-held, fried pies. Although he knows no examples of the technique being used for pre-baked, frozen pies, “I see no reason why you couldn’t do it,” he says.

From the crop to the cream
Unlike fruit fillings, “cream,” or crème, pies typically are not frozen raw for consumer bake-off. Designing a filling that could withstand that heat exposure simply is impractical. Crème pies almost exclusively are prebaked, filled shells either distributed fresh, or frozen requiring the consumer only to thaw them.

Although crème fillings may seem a great deal different, they have much in common with fruit-pie fillings — just without the fruit. In place of the fruit, crème pies have additional water or milk that’s sweetened, flavored and thickened with starches and/or hydrocolloids. Basically, they’re puddings, often aerated for a lighter texture.

Another difference with crème pies is that they typically are not as acidic as fruit pies, unless it’s a lemon meringue or Key lime variety. Most of the other flavors simply aren’t compatible. This means that many crème-pie fillings are made in the production facility, or are reconstituted from a supplier’s dry mix. A few companies do offer acidified, hot-pack crème fillings in a ready-to-use form. Generally, though, the flavor from the acid is noticeable.

Government’s piece on pies
As your company creates and manufactures pies, you no doubt will be establishing and checking quality measurements. For many foods, including pies, these quality standards are based upon what the marketing staff has determined consumers want — such as fruit content, crust color, etc. If you’re creating a foodservice pie that your company plans on selling to school systems or other government agencies, you may want to make sure that your pies also fit the commercial item description (CID) list established by the USDA’s Agriculture Marketing Service (AMS).

According to USDA, the AMS works with industry to develop and maintain CIDs for hundreds of food items. A CID is a simple description of the fundamental key attributes considered acceptable in a commercial product. They are based on product attributes that describe the odor, flavor, color, texture, analytical requirements, etc. for each product.

For frozen baked and unbaked pies, for example, the AMS CID specifies that, “Unbaked frozen pies shall be quick-frozen after makeup. All pies shall be held at 0°F or lower until receipt. They shall be not more than 45 days old at time of receipt at destination.” Regarding the fruit fillings, the CID declares that “The fruit fillings shall be prepared from fresh, canned, evaporated or dried fruit, or frozen fruit, with sufficient sugar added. The filling shall be formulated from not less than 50%, by weight, of fruit, based on the weight of fresh fruit.”

The pie CID even goes so far as to set a standard for appearance of a cut piece for both fruit and non-fruit pies. In the case of fruit pies, the CID specifies a viscosity “that will permit the baked pie to be sliced as desired without the filling spreading more than 3/4 inch from the cut edge within 10 minutes after slicing. There shall be no lumpy or ungelatinized starch pockets and no uncooked raw starch flavor.”
Sounds pretty specific, doesn’t it? The full description is actually four pages long. And just who, you may be wondering, is using these specifications?

According to the AMS, federal, state, and local organizations and other interested parties may use CIDs to purchase any of a full line of food items. The agency adds that CIDs currently are being cited by several large states in their procurement of food items with more states showing potential interest in using the descriptions in their own food procurement. Although it doesn’t do so for pies as of yet, the USDA uses CIDs for many food products in its school procurements. The listing of food product CIDs is available at the AMS website at: http://www.ams. usda.gov/fqa/cids.htm.

From plain to fancy, pies, turnovers and other similar products retain their historical popularity with consumers. Although creating them in the manufacturing environment may not be easy as pie, at least food technologists have the ingredient tools to get the job done without boiling over.

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