When Hippocrates first made the statement that opens this chapter, he may well have been referring to the medicinal magic of fermented foods. Fermentation isn’t a new practice; in fact, it began many centuries ago, making it one of the oldest methods to both preserve and prepare food. Essentially, fermentation facilitated our shift from being solely hunters and gatherers to becoming an agricultural society. The advent of food preservation techniques enabled people to create a future in one place, within a community, because they no longer had to constantly hunt for food. What Is Fermentation? Fermentation dates back to 5400 BCE with winemaking in Iran, milk fermentation in Babylon circa 5000 BCE, lacto-fermented cabbage in China circa 4000 BCE, leaven (now known as yeast) to raise bread dough in Egypt circa 3000 BCE, and pulque —the oldest alcoholic beverage on the North American continent—in Mexico circa 2000 BCE. The health benefits from eating fermented foods have been known for centuries. In 76 CE, Roman historian Plinio suggested that fermented milk alleviated gastrointestinal infections. Indeed, Romans obtained the medicinal benefits of lacto-fermented vegetables by eating sauerkraut. Voyagers, from the Roman emperor Tiberius in the first century CE to Captain James Cook in the late eighteen century, relied on sauerkraut to protect their crews from certain intestinal infections and diseases, such as scurvy caused by vitamin C deficiency. Because these voyageurs exported the process around the world, lacto-fermented vegetables include such traditional foods as cabbage in Asia, chutney in India, and relish in America.
The positive health benefits result from the life force inherent in fermented foods: probiotics. Probiotics, which actually means “for life,” are living microorganisms that confer a health benefit when consumed in the appropriate amount (more on this later). They manufacture vitamins, especially B complex vitamins such as niacin, biotin, folic acid, and pyridoxine, which support and increase the rate of metabolism; detoxify chemicals; promote cell growth including that of the red blood cells that help prevent anemia; and enhance immune and nervous system function. Probiotics increase the production of enzymes, which improves assimilation and absorption of nutrients from food, particularly proteins and fats. They are especially effective in crowding out growth of pathogenic microorganisms, thereby boosting immune system response.
THE PROCESS OF FERMENTATION
Fermentation happens when microorganisms (natural bacteria and some yeasts) feed on the sugar and starch in food, converting them into lactic acid in a process known as lactofermentation. There are several types of fermentation (which I’ll briefly discuss on page 7), but lacto-fermentation provides the most health benefits and, therefore, is the type we will focus on in this book. From a biochemical perspective, fermentation involves the metabolic breakdown of a nutrient anaerobically (without the use of oxygen). This breakdown produces ethanol, acids, gases, and other precursor molecules, which act as intermediate compounds in a chain of enzymatic reactions, from which a more stable or definitive product is formed. In a broader sense, lacto-fermentation creates beneficial bacteria, enzymes, vitamins, and various strains of probiotics (live beneficial microorganisms). An added benefit just happens to be an increased shelf life of food. Interestingly, fermentation doesn’t just encompass one basic process—it’s nearly as diverse as the range of foods it produces.
Fermented Food Classifications Not only does fermentation contribute to a diverse diet, but it also preserves, enriches, and detoxifies foods. It is the life force—that is, live bacteria, yeasts, and molds—behind fermented foods that confers its beneficial impact on your health. The sheer number and variety of these microorganisms is what creates the great diversity of fermented foods, which can generally be broken down into seven categories:
1. Cultured vegetable protein.
These usually consist of legumes, such as soybeans, which are used to produce tempeh, an Indonesian staple dating back two thousand years. Tempeh is made from cooked, hulled, fermented soybeans bound together with a mold that makes soy easier to digest. The result is a pressed cake, often used as a meat substitute, that can be sliced, grated, chopped, or even slipped onto a skewer for the grill.
2. High-salt-content, meat-flavored fermentation pastes.
These usually consist of salty and savory meat-flavored, protein-bound grains and legumes, such as soybeans, that are soaked, mashed, cooked, and left to ferment to make pastes and sauces. Most of these fermentations originated in Asian countries. Examples include soy sauce, miso, shoyu, Vietnamese mam, Indonesian trassi, and Malaysian belachan.
3. Alcohol fermentations.
These appear in biblical references as fermented wine. In this naturally occurring biological process, sugars, such as glucose, fructose, and sucrose, are converted into cellular energy by yeasts when placed in an environment absent of oxygen, whereby the microorganisms also produce ethanol (alcohol) and carbon dioxide as their metabolic waste products. We derive wine by fermenting the natural sugars found in grapes. Rum is produced by fermenting sugarcane, and whiskey, vodka, and beers are all produced by fermenting grain.
4. Vinegar fermentation.
This type of fermentation process results when you expose alcohol (ethanol) to oxygen. Vinegar is produced by a group of bacteria known as Acetobacter, which convert the alcohol into acetic acid, or vinegar. You may have experienced this type of fermentation if you’ve ever left a bottle of wine open for too long! Examples of acetic acid fermentation include apple cider vinegar, wine vinegars, coconut water vinegar, and African palm vinegar.
5. Alkaline-fermented foods.
These are less common foods made from various raw ingredients that are predominantly consumed in Southeast Asia and African countries. One such example is Japanese natto, made from cooked soybeans, or ugba from African oil beans. The proteins in the raw materials are broken down into their component amino acid and peptide parts, releasing ammonia and increasing the pH of the product, which results in the strong smell associated with these fermentations.
These are made from fermented grains, such as wheat or rye, which employ naturally occurring yeasts and Lactobacilli to raise the dough and create sourdough. Because the Lactobacilli produce lactic acid, sourdoughs produce a mildly sour taste, unlike breads made with baker’s yeast. The fermented mix of grain and water, called a “sourdough starter,” can be saved and used to start another batch of dough. The history of making leavened breads dates back to ancient times, with records as far back as six thousand years ago.
7. Lactic acid fermentation.
Lactic acid fermentation occurs when bacteria convert sugars present in the food into cellular energy and lactate, or lactic acid. Lactic acid is a natural preservative that inhibits putrefying bacteria, and the process is one of the most significant forms of fermentation in the food industry. Examples of vegetable lactic acid fermentations include sauerkraut, cucumber pickles, olives, kimchi, kefir, yogurt, soymilk, buttermilk, cheeses, and tofu. We have been harnessing this natural process to ferment traditional foods for thousands of years. The Greeks deemed this ancient process “alchemy,” to capture the magical transformations that occurred during fermentation. The earliest form of lactic acid fermentation is believed to have been milk fermented into yogurt, kefir, cheeses, and buttermilk. Raw milk, which is unpasteurized, sours quite rapidly due to the natural fermentation conducted by lactic acid bacteria. The bacteria convert lactose (milk sugar) into lactic acid, which serves as a preservative. Lactic acid is a natural antibiotic that keeps spoiling organisms away from the naturally preserved foods that contain it. Yet the benefits of lacto-fermentation do not stop at preservation. Lacto-fermentation creates an incredible array of flavors and textures. Lactobacilli—the most important lactic acid–producing bacteria—proliferate during the process of fermentation, making fermented foods so healthful. Because Lactobacilli increase the digestibility of vegetables by providing their own natural enzymes, our bodies do not have to completely rely on the digestive system to metabolize foods. These bacteria also increase the natural vitamin content of vegetables and produce antibiotics and cancer-fighting agents. Lactic acid also facilitates the proliferation of healthy gastrointestinal tract flora that are so integral to our well-being. We’ll be looking at each of these amazing abilities throughout part 1.