Preserving Your Fruit Options

Apple tarts. Caramelized bananas. Poached pears. These dishes commonly finish off a meal. But fruit is no longer bound to the dessert category, and has many other uses besides simply adding flavor.

From form to functionality, applications for fruits and the components contained within them abound. The components of fruits are very important in developing applications and formulations; acidity, sugar and pectin levels are three major factors to consider when using fruit.

What is a fruit? Botanically, fruits are categorized as the mature plant ovaries that house seed(s). This definition would include tomatoes and avocados, as well as cucumbers. Typically, consumers and manufacturers group fruits by their uses sweet or savory. Therefore the fruits cucumber and tomato are relegated to the vegetable category, while strawberries and rhubarb, neither a true fruit, are classified as fruits. Strawberries, the only fruit with the seeds on the outside, actually originate from the base of the flower, not the ovary. Botanically classified as a vegetable, rhubarb is a leaf stalk, but its frequently paired with strawberries in fruit applications, though it might also show up as the star of the dish as in spiced rhubarb crumble.

Fruit applications are becoming more inventive and crossing over from the sweet category into savory realms. Some pairings are very traditional, such as applesauce served with potato pancakes or duck à la orange. Others, such as chicken-apple sausage, and raspberry-chipotle roast pork, address the consumers needs for unique and innovative dishes that deliver bold flavor. Fruit can contribute to eye appeal, too. Pomegranate seeds can add a splash of brilliant red color to salads and dried cranberries in a scone provide both eye appeal and a wonderful tart flavor.

New and revived fruits are also making an appearance. The tangelo, a cross between a mandarin orange and a grapefruit, currently is widely marketed. Tangelos are larger than tangerines, contain fewer seeds and have the desirable flavors of the tangerine. They can be used in place of an orange or grapefruit. Pummelo, also called Chinese grapefruit, is making a comeback. Its flavor falls somewhere between a grapefruit and an orange, without the bitterness. New hybrids, such as Plucots (apricot/plum), with mostly apricot flavors, but the juicy texture and slight tartness of a plum, and the rosy red Peacotum (peach/apricot/plum), featuring mostly peach/apricot notes in the pale flesh, and a red skin, are not far behind. These new hybrids are typically interchangeable with their genetic parents and can add new dimension to an old dish.

First, consider the vast number of choices when determining which fruit to use in an application. Start with the basics: fresh, frozen, dried or canned? Fresh fruit has many advantages for providing true flavor impact, nutrients and beautiful color. On the other hand, fresh fruits also can be inconsistent in flavor, seasonal, difficult and costly to transport without damage, and carry a higher food-safety risk.

Dried fruits tend to be intense in flavor and easier to store, but are also higher in caloric content on a weight basis due to their low moisture content (and they can also be sugar infused and/or coated with oils to prevent sticking), can lose essential vitamins through heat exposure and may also discolor in the drying process. Additives can help alleviate some of these problems; processors treat light-colored dried fruit with sulfur dioxide to counter the browning effect. Canning can destroy or leach out some of the vitamins and minerals found in fresh fruits, and the fiber content is often reduced because, typically, canned fruits are peeled.

Frozen fruit comes in a variety of forms. Individually quick frozen (IQF) fruit does not contain added sugar, but block-frozen fruit may be added sugar-free, sugar-added or even packed in fruit juice. Pastes, purees and juices provide another possible choice. These give product designers alternatives to fit their specific formulation requirements for flavor, moisture, texture, sweetness, acidity, cost, etc. The type of fruit used will depend on the final application and the manufacturing parameters for the item. Fruit juice, for example, might be the perfect choice in a cream sauce for added sweetness and acidity, without the fiber and particulates. On the other hand, fresh fruit might be a better choice in applesauce, where texture and mouthfeel are very important.

Fruits generally are low in fat and protein but high in water content, carbohydrates, and certain minerals and vitamins. Even within a type of fruit, there may be different compounds present due to variety or growing conditions. For example, certain varieties of apples make a better choice for baking, such as those that hold their shape (Rome, Gala). Use full-flavored, bold apples for applesauce (Jonathon, Winesap). Other apple selections perform better in pies, when texture is key (Empire, Granny Smith, Braeburn). Still others are best for simply eating out of hand (Golden Delicious, Northern Spy).

The organic components of various fruits have been known and used in applications for a long time. Changes in the acidity, carbohydrates and pectins, the main components of fruits, can dramatically affect the fruits functionality and the final product.

Acidity is a vital element affecting performance of fruit in formulations. High acidity can serve as an antimicrobial agent, add flavor and stabilize gel formation. Acidity is easily measured by chemical titration or with a pH meter.

In application, acidity from citrus juice is used to cook raw fish/shellfish in ceviche by firming the flesh and turning it opaque. The combination of sweetness and acidity in a mango salsa pairs well with seared salmon, cutting through the oiliness of the fish. In the traditional Brigarade sauce, a rich and fatty hollandaise sauce is enhanced with the acidic and slightly bitter juice from the Brigarade orange, giving contrast and balance to the sauce. In an orange shallot vinaigrette, the acidity and sweetness enhance the salad greens fresh, natural flavors.

The consideration of sugar content is also essential in formulating with fruit. Typically, unripe fruits carbohydrates are in the form of starches. As the fruit ripens, the starches turn to sugars and develop the sweetness associated with ripe fruit. A banana is a good example; when green, bananas contain approximately 25% starch and 1% sugar. Natural enzymes convert much of the starch content to sugar during ripening, so fully ripened bananas have about 20% sugar.

It is important to make a distinction between ripe and mature fruit. The term ripe indicates optimal color, flavor and texture. Maturity is when the fruit is ready to eat, or if harvested, will be ready to eat with further ripening. This is an important factor in deciding when to harvest specific fruits. Citrus fruits have low starch contents and do not become sweeter after picking, so harvesting at the optimal acidity is essential. Conversely, a mango can ripen and convert starch to sugar after harvesting. Storage conditions also can dramatically affect sugar and starch content. However, green, or unripe, fruit does have its uses. Due to its high starch content, a plantain that is not fully ripened is perfect for frying to make chips. Green papayas can be used as a vegetable, still full of flavor, but without the sweetness.

The development of sugar and starch depends on the fruit variety. Sugar content is measured by Brix degrees, which relates the specific gravity of a solution to an equivalent concentration of pure sucrose. Calculations of sugar content are usually combined with acid content to develop a sugar-to-acid or Brix-to-acid ratio. These ratios combine the two variables to predict the tartness of the fruit, with a higher ratio indicating a less-tart fruit. For example, a lime has a sugar-to-acid ratio of 1:5 while a ripe kiwi is about 14:3. Cold storage can reduce enzymatic activity that can lead to over-ripeness. Other factors to reduce these ripening effects include lowering the oxygen level or, inversely, increasing the amount of carbon dioxide in the storage area.

Sweetness is an important component in formulation because it will affect the final flavor. Consider dried fruit added to a savory sausage stuffing or apricot juice added to a spicy barbecue sauce as examples of how sweetness can enhance other flavors and provide balance.

Pectin is another component of fruit that must be considered. Pectins are a group of water-soluble carbohydrates that increase as fruit ripens. They are used for their jelling properties, to add sheen to a sauce or to enhance mouthfeel. Fruits high in pectin include apples, quinces, red currants, plums and cranberries. Low-pectin fruits include berries, grapes, peaches, apricots, figs, pears and pineapples. Most pectin for commercial use is derived from citrus, especially grapefruit, due to the high levels in the white portion, or albedo, under the skin. Products such as jelly candies, yogurt, sauces, breads (as a preservative), and bakery fillings can all use pectin as an ingredient.

Some fruits contain unusual components that can cause curious reactions in formulations. Papaya, pineapple, kiwifruit and figs contain protease enzymes (papain, bromelian, actinidin and ficin, respectively), that can break down proteins. This makes them great natural meat tenderizers, but these enzymes must be destroyed by heat in gelatin applications since the proteases will break down the protein-rich gelatin. In marinades, fruit acids such as lemon juice (citric acid) or apple juice (malic acid), are natural tenderizers; they break down connective tissue and cell walls, tenderizing the product.

Another nontraditional use of fruit is as a fat replacer in meats. Both dried plums and cherries demonstrate these fat-replacement properties when added to beef patties and sausages. When added to ground beef, cherries have shown promise in retarding spoilage and also result in cooked ground beef with fewer carcinogens. Formulating with dried plums in many other applications adds color and sweetness, replaces fat, helps retain moisture, increases yield, and also inhibits pathogens such as E. coli.

Acidity, sugar content and pectin quality are only a few of the numerous factors to consider when developing new fruit applications. Remember, above all, its about the flavor!