How to Preserve Food Without Nutrient Loss

Categories: Food & Health
Posted on Friday, November 2nd, 2012 at 9:00 am by admin

Anyone who cans their own tomatoes, apple sauce, pickles, or jams knows that the difference between these simple preserves and the chemical-laced stuff you can buy at the store is immense. The flavor of home-preserved vegetables and fruits so far surpasses that of mass-produced stuff there’s almost no comparison.

But even preserving food at home by canning in a hot water bath can denature and destroy certain nutrients. To get the absolute most out of your home harvest or CSA haul you should investigate traditional methods of food preservation such as fermentation, drying, salt-curing, storage in oil or sugar, and more.

These methods are simple, require no fossil fuels, and are just as safe as hot-water-bath canning.

The following excerpt from Preserving Food Without Freezing or Canning: Traditional Techniques Using Salt, Oil, Sugar, Alcohol, Vinegar, Drying, Cold Storage, and Lactic Fermentation by the Gardeners & Farmers of Terre Vivant, will introduce you to some of these methods.

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PRESERVATION WITHOUT NUTRIENT LOSS

Canning or freezing. With few exceptions, these seem to be our only choices when we want to enjoy ready-to-eat fruits and vegetables out of season. As it is used today, the word “preserves” (like the French word conserves) evokes little more than food in cans or jars, preserved through sterilization. However, the original sense of the word was much broader, encompassing all known methods of food preservation.

These days, frozen foods tend to replace canned and bottled goods, since foods lose fewer nutrients through cold than through heat. But freezing is not very satisfactory either: it is expensive, consumes a lot of energy, and destroys many of the vitamins. In the home kitchen, we observe the same development as we have seen in industry: Canning, which was very popular in the 1960s (country folks each with their own sterilizers, putting up their own green beans, shell peas, and tomatoes), has given way to freezing. Emerging relatively recently (sterilization in the nineteenth century, freezing in the twentieth century), these two processes have relegated traditional food-preservation methods to obscurity, if not complete oblivion, as their scope of application has dwindled away. By far, the best example of displacement is lactic fermentation. Formerly used to preserve all sorts of vegetables, it has survived solely for making sauerkraut, and at that, more for gastronomic reasons than as a preservation process in its own right.

Fortunately, the traditional methods of preservation still live on in the French countryside, although they are rapidly disappearing. There is a wealth of knowledge to be gathered here before it falls into anonymity. This, then, is one of the goals of this book. Nevertheless, far from presenting a study of “preservation ethnology,” this collection is meant to be a practical guide. Every recipe we have included is still in use; some have even been enhanced by the advent of new technology, such as high-performance solar dryers, and water-sealed lactic-fermentation jars.

STOPPING FOOD CONTAMINATION

Left on its own, most fresh food quickly becomes unfit for consumption. Food is biochemically altered, due to the action of enzymes, and provides microorganisms—primarily bacteria—with a fertile environment in which to grow. To prevent this process, the most radical method is simply to kill the microorganisms by placing the food in an airtight container, and then heating it to temperatures greater than 100°C/212°F for a sufficient length of time. This technique, discovered by Nicolas Appert at the beginning of the nineteenth century, gave birth to the canning industry as we know it today.

Other methods of preservation seek to prevent microorganisms from spreading, without necessarily killing them. If the temperature is too low, acidity too high, water content insufficient, or salt concentration too high, microbes simply cannot multiply. As it is equally effective to destroy microorganisms or inhibit their growth, the method chosen should be the one that best protects the appearance, flavor, and nutritional value of the food, without adding undesirable substances. Of course, no method is ideal: During any preservation process, some alteration of the food is unavoidable. Moreover, no one method has proven superior to all others in all cases. And so, for most foods, we have a variety of techniques to choose from, each with its own advantages and disadvantages.

CHOOSING A METHOD OF PRESERVATION

Three methods overwhelmingly dominate the history of food preservation before the industrial age: cellar storage under cool, dark conditions, for certain fruits and winter vegetables (such as root vegetables, tubers, apples, and pears); drying, for fruit; and lactic fermentation for most other vegetables.

Natural-state preservation in a cellar is the most basic way to preserve foods that take well to this method. Although it is possible to dry apples and to lacto-ferment carrots, winter provisions have traditionally relied on apples stored in a cellar in their natural state, and carrots preserved likewise in a root cellar, or in the ground.

Nor is the choice between drying and lactic fermentation made arbitrarily. Experience has shown that dried fruits keep much better than most dried vegetables, retaining more flavor and vitamins due to their natural acidity. It is no coincidence that one of the few vegetables traditionally preserved by drying is the tomato, an acidic fruit-vegetable. As for lactic fermentation, people soon discovered that it was an unsuitable method for most fruit: Everyone knows that when fruit is fermented, we get alcoholic beverages.

Applications for the other methods of food preservation described in this book—sugar, salt, oil, vinegar, wine, and alcohol—are more limited, but certainly interesting nonetheless. For example, there are no substitutes for slow evaporation when preserving sugar-free jams, nor for oil and vinegar with herbs, salt with cod, and so on. In practice, the choice is often obvious, and simply depends upon the food to be preserved and its future culinary use.

ALTERING OR ENHANCING?

Inevitably, food is altered in the preservation process. However, unlike sterilization or freezing, many traditional methods do not necessarily mean a loss in flavor or nutritional value. Lactic fermentation, for example, enhances digestion and also increases the enzyme and sometimes the vitamin content, compared with the unfermented food. In other processes, the act of preserving often enhances the flavor of a food rather than its nutritional value. It might seem bizarre to preserve grapes in vinegar when this fruit keeps perfectly well by drying, but any gourmet will tell you that grapes in vinegar are divine with game or poultry.

Preserving basil in oil and vinegar serves two purposes: to preserve the flavor of this precious herb itself, and to impart its flavor to two ingredients used daily in cooking. And while drying preserves fruits, it also increases their sugar content, opening a new world of uses, such as sweetening desserts and certain beverages and providing energy-rich snacks for athletes. In bygone days, North Africans used raisins or dates, not cane sugar, to sweeten tea.

Over fifteen centuries ago, Hippocrates himself pointed out the positive effects of different preservation methods on the quality and properties of meat:

Meats preserved in wine become dry and are nourishing: they dry out because of the wine; they are nourishing because of the flesh. Preserved in vinegar, they ferment less, because of the vinegar, and are quite nourishing. Meats preserved in salt are less nourishing, as salt deprives them of moisture, but they become lean, dry out, and are sufficiently laxative.

The art of food preservation, which remains in part to be discovered, is this: For each food, use the method that not only best protects its nutritional value, but also enhances its flavor (and occasionally medicinal qualities), according to the eventual use we have in mind.

A NOTE ON FOOD SAFETY

Today, as home gardeners and cooks rediscover the joys of preserving, they often must confront a gap in cultural knowledge. Instead of turning to a parent or grandparent for advice, they turn to government agencies (chiefly the USDA) or to conventional books on canning, which advise sterilizing jars of food in either a boiling water bath or a pressure canner. However, as this book demonstrates, there are many traditional options for putting up fresh food that help food retain more of its flavor and nutritive value.

There is an important distinction to be made between sanitary and sterile conditions. Unless you live in an autoclave or hospital operating room, your kitchen (no matter how sanitary) will be far from sterile. Fortunately, absolute sterility isn’t necessary for most aspects of food preservation. For instance, though metal jar lids and tops will need to be boiled and sterilized, you can keep many disease-causing microbes in check simply by washing your hands frequently; by rinsing off raw foods; by thoroughly cleaning all utensils and cutting surfaces; and by following a few commonsense food safety guidelines (such as avoiding “cross-contamination” by using different utensils and surfaces to prepare raw meats and other foods).

In most (though not all) cases, food that has spoiled in storage should be readily apparent. Signs to look for include mold growing inside the lid of the container, on the food itself, or on the outside of the jar. Food that is badly discolored or darkened, or that is smelly or slimy, is likewise suspect and should be thrown away. When food is going bad, small bubbles may form inside a storage jar, and gas or liquid may escape in a rush when you unseal the container.

Remember that the point of preserving food is not to place it forever in suspended animation, but to extend the bounty of the fresh harvest season. Depending upon the type of food and the method of preservation used, this extension, or “shelf life,” might range from a few weeks to many months. Think of your pantry or cold cellar as a close cousin to the outdoor cold frame or unheated greenhouse—a simple, low-cost technology that can help you prolong the garden year and make the most of it. Many of the recipes in this book provide estimates on how long the prepared or stored foods will keep in good condition. Using this information, it’s possible to enjoy your preserved foods at their peak of flavor, just as you would fresh fruits and vegetables. Here’s to good food and good health!

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