Info

AAdapted from 2001 statistics from the Wine Institute (www.wineinstitute.org) bTotal based on 69 countries aAdapted from 2001 statistics from the Wine Institute (www.wineinstitute.org) bTotal based on 69 countries Although about 99 of the wine produced throughout the world is made from grapes, juice from other fruits can also be made into wine. Berries, including raspberries, boysen-berries, and strawberries, are common substrates. Many wines also are made from tree fruits, including apples and...

Acidcoagulated cheeses

In the United States, the most popular of the acid-precipitated cheeses are Cottage cheese and cream cheese. And although per capita consumption of Cottage cheese (all varieties) has declined in the past twenty years by nearly 30 (despite modest increases in low-fat versions), cream cheese per capita consumption has increased by more than 100 (from less than 0.5 Kg to more than 1 Kg per person per year). This increase in cream cheese consumption is undoubtedly due to an equal increase in the...

Starter cultures

The composition of the starter culture depends on the intentions of the cheese maker. If the cheese-making procedure includes a step where the curds will be exposed to high temperatures, such as during manufacture of Swiss, Parmesan, and Mozzarella cheese, then a thermophilic lactic acid bacterial culture able to withstand those temperature must be used. If a particular flavor compound is desired, such as diacetyl in Gouda cheese, then again, the culture must contain specific organisms capable...

Champagne

Champagne is made from Chardonnay, Pinot Noir, and Pinot Meunier grapes grown in the Champagne district. This is a northern grape-growing region and the still wines made from individual cultivars (the Pinots make red wines and the Chardonnay is used for white) are not particularly remarkable (some might call them insipid). However, when the base wines are appropriately blended (a skill first perfected by the monk Dom P rignon), the wine assumes the best qualities of each individual cultivar....

Pasteurize Refrigerate

Manufacture of sauerkraut. Adapted from Harris, 1998. most certain to occur if too much or not enough salt is added or if the salt is not uniformly distributed, because salt performs several essential functions during the sauerkraut fermentation. Very soon after the salt is mixed with the shredded cabbage, water begins to diffuse out from the interior of the plant tissue to the exterior medium, due to simple osmosis. The brine that forms also contains sugars and other dissolved...

Hard Italian Cheese

Given the popularity of Mozzarella cheese and Italian cuisine, in general, it is not surprising that production of other Italian cheeses, such as Parmesan, Romano, and other hard grating types, have increased by more than 120 in the last twenty years.Although Parmesan is the prototype of the hard Italian grating type cheeses, there are many variations of this cheese, including Romano,Asiago, and Grana. As recently as 2002, the Food and Drug Administration's official Standard of Identity for...

Inoculation

After the wort is cooled and aerated, the yeast culture is, at last, added to the wort, in a step called pitching. Brewing yeast strains are dramatically different from the Saccharomyces cerevisiae strains used in the laboratory in many important respects (Box 9-5). In addition, there are two types or strains of brewing yeasts that are used, depending on the type of beer being produced, and these strains also differ physiologically, biochemically, and genetically. Many of these differences are...

Other Bacteria Important in Food Fermentations

In addition to the lactic acid bacteria, several other genera are involved in fermented foods. In most cases, these bacteria are used for a singular purpose, that is, they are involved in just Table 2.5. Fermentation characteristics of Lactobacillus1 Table 2.5. Fermentation characteristics of Lactobacillus1

Wheat beer

Wheat beers have long been popular in Europe, but have only recently become known to U.S. consumers. They are made using wheat malt combined with barley malt in ratios varying from 1 3 to as high as 3 1. These beers are generally thinner and more sour than barley malt beers, and are usually high in phenolic compounds.They also often have a somewhat cloudy appearance. However, their unique flavor, due in part, to vinyl guaiacol generated from ferulic acid, is particularly appreciated by some...

Wort

Eventually, the temperature of the mash is raised to 75 C, which effectively inactivates nearly all enzymatic activity. The insoluble material in the mash liquid is then separated by one of several means (discussed below).This is an important step because the mash still contains grain solids and insoluble proteins, carbohydrates, and other materials. In addition, within the mash solids is a reasonable amount of soluble materials,including fermentable sugars, that would otherwise be discarded...

C

Foods, such as wine, their natural presence on grapes and equipment is sufficient to initiate a fermentation. Several different yeasts may be involved in natural or spontaneous wine fermentations, usually in a successive manner, where one species is dominant for a time, then gives way to others (Chapter 10). However, in most modern wine fermentations, as well as beer and bread fermentations, starter culture yeasts are used, selected on the basis of their physiological and biochemical...

Carbonation

Of all the post-fermentation steps, perhaps none is as important as carbonation. Carbona-tion provides sensual appeal by enhancing mouth feel, flavor, body, and foam (or head).The CO2 preserves the beer by reducing pH and the oxidation-reduction potential (Eh), such that various aerobic, acid-sensitive spoilage organisms are inhibited. Carbonation of beer can occur naturally, via a secondary fermentation, or mechanically, by directly adding CO2 after the conditioning and filtration steps. As...

Fermentation

The miso fermentation occurs in a manner similar to that of soy sauce, in that the hydrolysis of complex macromolecules to form simple nutrients and the subsequent fermentation and metabolism of those nutrients occurs essentially at the same time. As it does with soy sauce, the koji serves both as the source of proteolytic and amylolytic enzymes, as well as a substrate source for those enzymes.About 50 of the total protein and 75 of the polysaccharides are completely hydrolyzed to amino acids...

Moldripened Cheese

Aside from the fact that the two main mold-ripened cheeses, the blue-type and the Brie-type, are both fungal fermentations, they share few common properties. The blue mold cheeses contain visible mold growth throughout, at the surface, and within the curd. The mold responsible, Penicillium roqueforti, produces blue-green mycelia, in addition to a myriad of enzymes that ultimately generate typical blue cheese flavors. In contrast, the Brie-type cheeses are made using Penicillium camem-berti,...

Pasteurization and packaging

The refined, raw soy sauce is usually heat pasteurized, either in bulk or, more commonly, in a plate-type heat exchange system (at 70 C to 80 C). Flash pasteurization at 115 C or higher for three to five seconds may also be used. Table 12.4. Concentration of important flavor compounds in shoyu1 Table 12.4. Concentration of important flavor compounds in shoyu1

Atp

Transport and metabolism of glucose, fructose, maltose, and sucrose by Saccharomyces cere-visiae. Fructose and glucose are transported by one of several different hexose transporters via facilitated diffusion. Sucrose is hydrolyzed by a secreted invertase. Maltose transport occurs via a proton symport-mediated maltose permease. Once inside the cell, maltose is hydrolyzed by maltase to give free glucose. The accumulated monosaccharides are phosphorylated to glucose-6-phosphate...

Aging

The last step in the cheese making process has as much influence as any previous step with regard to the properties and qualities of the finished cheese. As noted in Chapter 1, it is a fine line that separates the production of a perfectly flavored, three-year old Cheddar cheese and a bitter, rancid, sour Cheddar cheese that is quickly rejected by any discerning consumer. Although the distinctly different properties of both of these two cheese are the result of microbial and enzymatic...

Ice and dry beers

Two other types of beer that gained a following in the 1990s, but whose popularity has since faded somewhat, are ice beers and dry beers.Al-though made by different processes, both ice beer and dry beer contain more ethanol than conventionally-processed beers and are thought to impart a smoother flavored beer with less aftertaste. Ice beers are manufactured according to the freeze concentration principle namely, by cooling the beer to temperatures as low as 4 C, ice crystals will form, which...

In

Mycotoxins in Fungal Fermented Products Cause for Concern (Continued) According to another recent investigation, mutations in a second regulatory gene, aflJ (see above), may also be responsible, in part, for non-expression of afl genes in A. sojae. In A.parasiticus, aflJ gene product, AflJ, upregulates synthesis of aflatoxin. Mutations in aflJ decreased transcription of both afl structural genes and aflatoxin synthesis, although alfR expression was not affected (Chang, 2003).Thus, it...

Manufacture of fermented pickles

The actual process steps used for the manufacture of fermented pickles are similar to those used for making sauerkraut. Both rely on salt, oxygen exclusion, and anaerobiosis to provide the appropriate environmental conditions necessary to select for growth of naturally-occurring lactic acid bacteria. There are, however, several differences between pickle and sauerkraut fermentations. First, salt concentrations are higher than those used for sauerkraut, resulting in the development of a less...

Organoleptic

Simply stated, fermented foods taste dramatically different than the starting materials. Individuals that do not particularly care for Limburger cheese or fermented fish sauce might argue that those differences are for the worse, but there is little argument that fermented foods have aroma, flavor, and appearance attributes that are quite unlike the raw materials from which they were made.And for those individuals who partake of and appreciate Limburger cheese, the sensory characteristics...

Milk treatment

Yogurt can be made from skim (non-fat), reduced fat, or whole milk.As is true for all dairy products, but especially so for yogurt and other cultured milks, it is important to use good quality milk, free of antibiotics and other inhibitory substances. The first step (Figure 42) involves adding nonfat dry milk to the milk to increase the total solids to 12 to 13 , sometimes to as high as 15 .Alternatively, the total milk solids can be increased by concentrating the milk via evaporation. Other...

Mashing

It is during the next step, mashing, where the koji enzymes begin to hydrolyze proteins, poly-saccharides, and other substrates, and where microorganisms begin to use the products of these reactions. First, however, a high salt brine containing 20 to 25 sodium chloride is added to the solid material. The volume added may vary, depending on the manufacturer's specifications, but a ratio of about 1 1.2 to 1 1.5 (solid to brine) is normal. The high salt concentration in the mash (ranging from 16...

I Oh Ho H

Formation of acetaldehyde by yogurt bacteria from pyruvate and threonine. Adapted from Chaves et al. 2002. consumers as flavor. Coagulated milk is essentially a protein gel that imparts viscosity, mouth feel, and body to the finished product. Formation and maintenance of the gel structure, therefore, is important for yogurt quality. The gel properties are affected by the ingredients in the yogurt mix, how the yogurt mix is processed and produced, culture activity, and...

Tpp

CO2 diacetyl reductase diacetyl acetoin catalyzed by a-acetolactate synthase and requiring high concentrations of pyruvate. The a-acetolactate is unstable in the presence of oxygen and is finally decarboxylated, nonenzy-matically, to form diacetyl. It is important to note that diacetyl is not necessarily the terminal end-product of the pathway. Further reduction of diacetyl can also occur, forming acetoin and 2,3-butanediol, compounds that contribute no flavor or aroma to the product. Following...

Spoilage by yeasts

Yeasts represent a major cause of wine defects and spoilage. Moreover, since yeasts are an expected part of the natural flora of grapes and must, their growth before, during, and after the wine fermentation is difficult to control. For example, Kloeckera apiculata, one of the yeasts involved in the early stages of a natural fermentation, can produce high enough levels of various esters (mainly ethyl acetate and methylbutyl acetate) to cause an ester taint, which has a vinegar-like aroma. Once...

Preface

This project started out innocently enough, with the simple goal of providing a resource to students interested in the microbiology of fermented foods. Since 1988, when I first developed a course in fermentation microbiology at the University of Nebraska, there has not been a suitable student text on this subject that I could recommend to my students. Peder-son's Microbiology of Food Fermentations had last been published in 1979 and Fermented Foods, by A.H. Rose, was published in 1982. Brian...

Acknowledgments

I am grateful to the many colleagues who reviewed chapters and provided me with excellent suggestions and comments. Any questionable or inaccurate statements, however, are due solely to the author (and please let me know).To each of the following reviewers, I thank you again Andy Benson, Larry Beuchat, Lloyd Bullerman, Rich Chapin, Mark Daeschel, Lisa Durso, Joe Frank, Nancy Irelan, Mark Johnson, Jake Knickerbocker, David Mills, Dennis Romero, Mary Ellen Sanders, Uwe Sauer, Randy Wehling, and...

Carbohydrates

Carbohydrates represent the main fraction of flour, accounting for up to 75 of the total weight. This fraction is largely comprised of starch, although other carbohydrates are also present, including a small amount (about 1 ) of simple sugars, cellulose, and fiber.The main carbohydrate component, however, is starch, which consists of amylose, an a-1,4 glucose linear polymer (about 4,000 glucose monomers per molecule) and amylopectin, an a-1,4 and a-1,6 glucose branched polymer (about 100,000...

End products

The most obvious and most important end product of the bread fermentation is CO2. It is, after all, the CO2 that is mainly responsible for transforming the stiff, heavy, dough into a spongy, elastic, and airy material. Some of the CO2 dissolves in the water phase (even though CO2 solubility is generally low), causing a slight decrease in pH. Eventually, the CO2 saturates the aqueous environment surrounding the yeast microcolonies.At that point, the CO2 evolves into the dough. The CO2 causes the...

Raw materials preparation

The manufacture of koji starts by treating the raw materials.When soybeans are used, they are first soaked for about twelve hours in several changes of water. For traditional koji-making, they are then cooked, usually with steam under pressure, for one hour a process called puffing. For some products, soybean koji also contains wheat, which is prepared by roasting wheat kernels (or wheat flour) at a high temperature, followed by a crushing step. Rice koji for sake manufacture is prepared from...

Miso

Miso is another popular fermented soy product in the Orient.Although miso originated in China and Korea more than a thousand years Box 12 2. Reducing the Dark Color in Soy Sauce The dark brown color of shoyu and other types of soy sauce is ordinarily an expected property. A brown color is certainly a major part of the overall appearance of many of these products. However, for many applications in particular, when soy sauce is used as an ingredient in processed foods a lighter, amber-like color...

Culture

Most commercial cultures for sausage are supplied in either a frozen or lyophilized form. Frozen cultures, which are more common in the United States, are supplied as thick slurries in peel-back or flip-top cans ranging in size from 20 ml to 250 ml. Cell densities typically range from 108 to 109 cells per ml.A typical 70ml can is sufficient for about 150 kg of sausage batter.These cultures are shipped frozen under dry ice and users are instructed to store the cans at 40 C or below. The cans...

Vinegar Quality

At least two criteria must be considered to assess the quality of vinegar. In contrast to other fermented foods, where authenticity is rarely disputed, vinegar can be adulterated, either with less expensive vinegar or with other acidic agents. In rare instances, adulteration is caused by even more dubious means. For example, acetic acid produced via chemical synthesis can be diluted and then marketed (illegally) as fermentation-derived vinegar. Thus, the first quality criterion is based on...

Cheese

We are still, however, far from having arrived at a complete elucidation of all the questions involved. It is particularly difficult to understand how various sorts of hard cheese, apparently containing the same microflora, should each have its own characteristic taste and smell. There can hardly be any doubt that these sorts of cheese in reality contain different species of bacteria, only we are unable to distinguish them by the methods hitherto available. From The Lactic Acid Bacteria by S....

Flavor of Fermented Meats

Like other fermented foods made with a lactic acid starter culture, the main flavor compounds are acids, principally lactic and acetic, derived via metabolism of sugars. In many of the U.S.-produced products that are cured with nitrite, fermented at high temperatures for a short time, and cooked following fermentation, there is only a brief opportunity for development of other flavors. In contrast, a much more complex array of flavor compounds is produced in sausages in which nitrate is used as...

Introduction

In 1992, a research team from the Applied Science Center for Archaeology at the University of Pennsylvania made a discovery that was publicized within archaeology circles (and college campuses) around the world.These researchers had analyzed a small amount of organic residue from inside an ancient pottery vessel that had been retrieved from the Zagros Mountains of Western Iran. When the residue from this clay pot (which itself was dated circa 3500-3100 B.C.E.) was analyzed, the results revealed...

O Cl

XAdapted from Bergey's Manual of Systematic Bacteriology, Volume 2 (1986) 2Cel cellulose Fru fructose Gal galactose Lac lactose Mal maltose Suc sucrose 4Variable reaction, depending on strain or subspecies 5Weak positive reaction one application and perform only one major function. These non-lactic acid bacteria represent several different genera and include both Gram positive and Gram negative bacteria. Their taxonomical position and general properties are given below. How they are actually...

Kefir

Kefir is a fermented dairy product that is described in many reference texts and has long been of academic interest to microbiologists, but was one for which few U.S. students (or consumers for that matter) had any first-hand knowledge. Although several brands of kefir are now available throughout the United States, it is still a mostly unknown product.This is despite the popularity of this product throughout a large part of the world. In the Middle East, Eastern Europe, and Central Asia,...

Bibliography

In B.J.B.Wood (ed.) Microbiology of Fermented Foods, Volume 1, 1998. Blackie Academic and Professional (Chapman and Hall). London, United Kingdom. Adams, M.R., and M.O. Moss. 1995. In Food Microbiology. Royal Society of Chemistry. Cambridge, U.K. Beppu,T. 1993. Genetic organization of Acetobacter for acetic acid fermentation. Antonie Van Leeuwenhoek 64 121-135. Cleenwerck, I., K. Vandemeulebroecke, D. Janssens, and J. Swings. 2002. Re-examination of the genus...

Spoilage by fungi

Fungal growth and spoilage rarely occurs during the wine fermentation, since most fungi are aerobic and sensitive to ethanol. Rather, molds are most important before and after the wine is made. Fungal growth on grapes is one of the most serious problems encountered in grape viticulture, causing considerable loss of crop.If not controlled, rots, mildews, and other fungal diseases can wipe out an entire vineyard. As noted earlier for sweet botryized wines, a fine line sometimes separates spoiled,...

Spanishstyle

Spanish-style olives are harvested when the skin color is green or straw-yellow. They are then treated with a lye solution for four to twelve hours at 15 C to 20 C to de-bitterize the olives via hydrolysis of oleuropein. The lye concentration may range from 0.5 to 3.5 , depending on the size and type of olive. Once the lye has penetrated to just outside the pit (about two-thirds of the way from the skin to the center), the olives are washed in one to three rinse cycles of water to remove the...

Glycolysis

Following transport, the accumulated mono-saccharides are rapidly phosphorylated by hexokinases or glucokinases.As for the hexose transport systems, hexokinase enzymes (there are at least two, hexokinase PI and PII) have broad substrate specificity, being able to phos-phorylate glucose and fructose, as well as man-nose. The sugar phosphates then feed into the glycolytic or Embden-Meyerhoff (EM) pathway (Figure 8-8), with the eventual formation of pyruvate. Reducing equivalents, in the form of...

Crushing and Maceration

The purpose of crushing is to extract the juice from the grapes. Before the grapes are crushed, however, leaves, large stems, and stalks are removed. Some wine makers may not remove all of the stems to increase the concentration of tannins and other phenolic compounds that are present in the stems and extracted into the juice. Once the extraneous material is separated and removed, the grapes are crushed by one of several types of devices. Roller crushers consist of a pair of stainless steel...

Plantbased Fermentations

Soy and rice are the most frequent substrates for Asian fermented foods.Wheat flour is also often included as an ingredient in many of these prod-ucts.With few exceptions, however, there is a common starting material koji that is essential for most Asian fermented foods. As will be described in more detail below, koji is simply a moldy mass of grain, and is derived from the Chinese word meaning moldy grain. In some cases, the koji mold is added to a portion of the raw material which is later...

Salt

Salt is an essential ingredient in all types of sausage products (fermented or not). Salt, added in concentrations of 2.4 to 3 , performs several critical functions. First, it is responsible for extracting and solubilizing the muscle proteins, which are ordinarily in an insoluble form. Once extracted and solubilized, the proteins form a sticky film around the meat particles, creating an emulsion-type structure. Second, salt provides flavor. Finally, salt is the primary means, at least...

Surfaceripened by Bacteria

Among the cheeses that are the most aromatic and flavorful, Limburger, Muenster, Brick, and other surface-ripened cheeses are right at the top of the list.A well-ripened Limburger can fill the room with the strong sulfury volatile compounds that are produced by Brevibacterium linens. This organism (and others that are generally present see below) is neither added to the milk nor curds, but rather is applied to the cheese after its manufacture.As profound as is the aroma and flavor of this...

Koji

The manufacture of traditional soy sauce or shoyu starts with preparation of the raw materials and addition of the koji (Figure 12-1).The soy fraction consists of either whole beans, soy meals, or soy flakes. It is now common to use de-fatted flakes rather than whole beans or flakes to improve yield and reduce fermentation times. When beans are used, they are washed, sorted, and soaked overnight, then cooked under pressure and cooled rapidly. Flakes are simply soaked and cooked (as for whole...

Sugar

The next essential ingredient is the sugar or carbohydrate.Although glucose, in the form of the polymer glycogen, is initially present in muscle tissue of slaughtered animals,glycogen stores are quickly depleted during the postmortem period.Thus, fresh meat contains little fermentable sugar, and addition of sugar is necessary. Glucose is most common in the United States, and is added to about 1 to 2 of the total batter weight. Since the amount of acid produced by the lactic culture is directly...

Organic Acids

Organic acids comprise the second most plentiful non-water constituent in must. Although the organic acids are present at relatively modest concentrations, typically ranging from 1 to 2 , their effect on wine quality is extremely im-portant.These acids are responsible for the low and well buffered pH of the must and the wine (usually between 3.0 and 3.5).That wine is so well preserved is due not only to the ethanol and low pH, but also to the presence of organic acids that have powerful...

Malt enzymology

The carbohydrate fraction of malt is mostly in the form of starch.Approximately one-fourth of malt starch is amylose, a linear polymer consisting of glucose, linked a-1, 4. The remaining starch, three-fourths of the total, is amylopectin, which contains not only linear glucose, but also glucose in branched a-1, 6 linkages. The main starch-degrading enzymes synthesized during malting are a-amylase and p-amylase. The former is an endoenzyme, acting primarily at in tramolecular a-1, 4 glucosidic...

Fermented Fishtype Foods

Although fish and shrimp sauces and pastes are mostly unknown to Western consumers, they are staple items in much of Southeast Asia, including Thailand, Vietnam, Malaysia, and the Philippines (from where such products were thought to have evolved). Although fresh fish has long been widely available throughout this region, refrigeration has not. Thus, fish would likely spoil before it could be consumed. In contrast, fish-type sauces and pastes not only have a long shelf-life, they also serve as...

Manufacture of natto

The manufacturing procedure for natto begins like that for miso however, the organisms involved in the fermentation are different and the final product bears little resemblance to miso. Natto is made from whole, somewhat small-sized soybeans that are cleaned, soaked for twelve to twenty hours at ambient temperature, and steamed at 121 C for twenty to forty minutes. The thoroughly cooked and cooled beans are then inoculated with about 106 to 107 spores per Kg of Bacillus subtilis var. natto...

Adjuncts

The mash, as described so far, contains only the malt and brewing water. The malt, as stated above, supplies the enzymes and the enzyme substrates. Many of the European beers, as well as the micro-brewed beers produced in the United States, are made using 100 malt mashes. However, the most widely-consumed beers in the United States, those made by the large breweries, contain an additional source of starch-containing material in the form of corn, rice flakes, or grits. These materials are called...

Production Principles

In a general sense, fermented vegetable technology is based on the same principles as other lactic acid fermentations, in that sugars are converted to acids, and the finished product takes on new and different characteristics. In reality, however, the actual production of fermented vegetables occurs quite differently. For example, whereas cheese, cultured dairy products, and fermented meats are usually produced using starter cultures, the fermented vegetable industry still relies on natural...

Pickled Cheese

High-salt, high-acid cheeses were likely among the first cheeses intentionally produced by humans. They would have had a much longer shelf-life than other similarly produced soft cheeses that had lower salt content. These cheeses have long been popular in Greece, Turkey, Egypt, Israel, and other Middle Eastern countries, as well as the Balkan region of Eastern Europe. In the past twenty years, production and consumption of these cheeses has spread throughout Europe, the United Kingdom, the...

Ripe or Californiastyle

California-style olives are the most popular olives consumed in the United States. Both the black and green versions are produced from the same starting material green olives (with a bit of cherry-red blush). For both types, the olives are lye-treated, as described above for Spanish olives, except that several applications are used. In the case of green olives, the lye is removed and the olives are washed in water, and then dilute brine is added. The olives are then canned (after a pitting...

B

Thus, the acid tolerance response may not only protect the cell against low pH, but also heat and oxidative stress. In vegetable fermentations, the other important stresses encountered by lactic acid bacteria are high salt concentrations and high osmotic pressures. Salt concentrations in sauerkraut brines are around 0.4 M, giving an osmolality of about 0.8 Osm. Pickle and olive brines may contain more than 1.0 M salt, or osmolalities above 2 Osm. Salt is an...

Stuck Fermentations

Despite the apparent simplicity of the wine fermentation, as evidenced by so many successful outcomes, there are occasions when the fermentation fails. Such wines typically contain a significant amount of residual, unfermented sugar and an insufficient concentration of ethanol. The fermentation may actually still be occurring, just more slowly, or it may be at a complete standstill. These slow or halted fermentations are referred to as sluggish or stuck fermentations, respectively.Although they...

Shredding and salting

Once the outer leaves and any spoiled leaves are removed, the cabbage heads are washed and the core is drilled out.The cabbage (along with the core) is shredded (according to the manufacturers specifications) to make a slaw. The shredded leaves are then weighed and conveyed directly to tanks or are deposited first into tubs or carts and then transferred into tanks. Salt can be added as the slaw is conveyed or it can be added to the slaw when it arrives in the tanks. In either case, both the...

O

Bread by adding these nutrients directly to the dough. Dough improvers. Mixing the ingredients and making an elastic dough can often be a slow process, due to the sticky gluten protein that forms when the flour is hydrated. Reducing agents, such as cysteine, are used to speed up dough mixing, by decreasing the number of disulfide cross-links that make gluten so highly elastic (as described in the next section). In other words,these agents weaken the dough structure and decrease mixing times....

Malolactic Fermentation

A certain amount of acidity is expected and desirable in wine. Red wines typically have a pH of 3.3 to 3.6 white wines are usually slightly more acidic. Some grapes, and the musts made from those grapes, however, may contain high levels of organic acids, such that the pH is too low (i.e., < 3.5).Wines made from those grapes will suffer from excess acidity, a serious and readily noticeable flavor defect. Of the organic acids ordinarily present in grapes, malic acid is particularly important...

Pressing and refining

After the fermentation is complete and the mo-romi is adequately aged, the soluble soy sauce must be separated from the solid residue.This is done using hydraulic filter presses that force the moromi through multi-layered sheets of cloth or nylon filters. Pressing can last for several days, with pressures increasing incrementally, up to 100 kg per cm2.About 90 liters or more of liquid material can be obtained from 100 liters of mo-romi.The solid filter cake byproduct ordinarily is used as...

Cheddar family

Cheddar cheese is the most popular cheese consumed in the United States, with per capita consumption in 2001 of nearly 6 kg (12.7 pounds) per person per year (including other Cheddar types). Approximately 1.2 billion Kg (2.7 billion pounds) are produced each year in the United States. Several cheeses, including Colby, Monterey Jack, and other washed or stirred curd cheeses, are closely related to Cheddar cheese and are collectively considered as American type cheeses. However, this designation...

Polysaccharides

The main polysaccharide in grapes or must is pectin, a structural carbohydrate that provides structural integrity to the plant cell walls. The pectin concentration in the must can be as high as 5 g L,which could potentially cause the wine to become cloudy. However, most of the pectin is either precipitated out during fermentation or is hydrolyzed to soluble sugars by exogenous microbial pectinases. The latter are commercially available and are used not only to enhance maceration and pressing,...

Fermented Foods in the Twentyfirst Century

For 10,000 years, humans have consumed fermented foods. As noted above, originally and throughout human history, fermentation provided a means for producing safe and well-preserved foods. Even today, fermented foods are still among the most popular type of food consumed. No wonder that about one-third of all foods consumed are fermented. In the United States, beer is the most widely consumed fermented food product, followed by bread, cheese, wine, and yogurt (Table 1-3). Global statistics are...

History

Like the bread, wine, dairy, and other fermentations described in earlier chapters, Asian-type fermented foods also evolved thousands of years ago. In addition, these Asian fermented foods had many of the same general characteristics and properties as those that developed in Middle Eastern and Western cultures. That is, the products were comprised of ingredients native to their geography, they had enhanced functional properties, and they were well preserved. Likewise, Asian fermented foods were...

Product characteristics

The final chemical composition of soy sauces depends on the specific type being produced (Table 12-2). In general, the greater the proportion of soy beans, relative to wheat, the greater will be the total nitrogen concentration. Conversely, products made using higher levels of wheat will contain less nitrogenous material, but more reducing sugars. Thus, shoyu tamari, which is produced mainly from soy beans, contains nearly four times more total nitrogen, but six times fewer reducing sug- Table...

Spoilage and defects

Despite the high salt concentration and relatively low pH, growth of spoilage organisms in miso can occur, resulting in gas, off-odors, over-acidification,and surface slime.Yeasts and bacteria responsible for these defects include Hansenula and Z. rouxii, Pediococcus acidi-lactici, and Bacillus sp. Spoilage is more likely to occur when salt levels are reduced (< 12 ) or when the koji molds are inhibited. Pasteurization, either before or after packaging, inactivates these organisms. However,...

Fortified wines

Fortified wines are those to which distilled spirits (containing as much as 95 ethanol) are added to raise the total ethanol concentration to 15 .Not only do these wines contain higher concentrations of ethanol, the source of the ethanol (e.g., brandy) is also important since they may contribute unique flavor compounds to the finished product. Aside from this common feature, however, a variety of quite different fortified wines exist. Included are whites and reds, dry and sweet. Fortification...

Process aids

Various approved additives are frequently used during the post-fermentation steps.These include agents to improve flavor, color, appearance, and stability. Hop extracts are sometimes added late in the process to provide additional hop flavor. Another important additive is pro-teolytic enzymes, which are used as chill-proofing agents. These enzymes hydrolyze proteins that would otherwise precipitate and form complexes with tannins and other polyphenolic compounds at low temperatures and give a...

Azm

Conversion of 2,4,6-trichlorophenol to 2,4,6-trichloroanisole (TCA). Biochemical evidence suggests that TCA is synthesized from chlorophenol precursors by a methylation reaction (Alvarez-Rodriguez et al., 2002). Chlorophenols are highly toxic, and this methylation reaction has been thought to be involved in detoxification (TCA, although odorous, is non-toxic). It has recently been reported that cork-associated fungi can perform this reaction and produce TCA in cork, provided...

Mty

Adapted from Yoshiwawa and Ishikawa, 2004. for forty to forty-eight hours at 30 C to 35 C under high humidity.The koji is mixed at intervals to re-distribute the growing fungi, maintain aerobiosis, and prevent excessive heat build-up. When finished, the rice should be covered with fungal mycelia and should contain high amylolytic and proteolytic activities. Next, the koji is moved to a tank, and the steamed rice (from above) and water are added.This material,...

C2

Alignment of the three main classes of lactococcal bacteriophages the prolate headed c2, the small isometric headed sk1 (936 class), and the small isometric headed Tuc2009 (P335 class). Early, middle, and late expressed regions and putative functions are indicated. Adapted from Desiere et al., 2002 and Stanley et al., 2003. Not all bacteriophages infect and lyse their host cells. Some bacteriophages have two routes of infection or lifestyle choices lytic or lysogenic. Lytic phages...

Bitterness and accelerated ripening

For most cheeses, production of good aged cheese flavor and texture requires that there be significant hydrolysis of casein. At the same time, the main flavor defect in cheese is bitterness, which is also caused by casein hydrolysis and subsequent formation of bitter peptides. Thus, aging cheese is like walking a tightrope it requires a fine sense of preparation, balance, and proportion.A single misstep may lead to an unacceptable end. Accelerated ripening obtaining good cheese flavor and...

Conditioning

Conditioning can occur by one of several methods. In traditional ale manufacture, the beer is pumped from the fermentor into wooden casks ranging in size from 20 L to more than 200 L. Stainless steel casks have replaced many of the wood casks, although the latter are still available. Sugar is added to induce the secondary fermentation, and additional hops and fining agents (see below) may also be added. The casks are held at 12 C to 18 C for up to seven days. Following the maturation period,...

Co2

Precursor-product exchange systems in lactic acid bacteria. Three examples are shown. In Streptococcus thermophilus (and some strains of Lactobacillus), lactose is transported by the LacS system via proton-symport (panel A). Intracellular hydrolysis releases free galactose, which is not metabolized, but is instead secreted. The efflux reaction, which appears to be favored in most strains, then drives uptake of lactose. Citrate-fermenting lactic acid bacteria transport citrate via the...

Cutting and cooking

The coagulated mass is next cut using harp-like, wire knives that cut the curds into die-sized particles. The knives are constructed such that the curds can vary in size. Since this step is performed to enhance syneresis, the size, or more importantly, the surface area of the curd particles, has a major influence on the rate of water removal from the curd. Hard, low-moisture cheeses like Parmesan and Swiss are typically cut into kernel or wheat berry-sized curds, whereas soft, high-moisture...

Cool4c

Manufacture of cultured buttermilk. producing lactic acid, as well as small amounts of acetic acid, ethanol, and carbon dioxide. These metabolic end-products contribute to the flavor and, in the case of the carbon dioxide, to the mouth feel of the product. Importantly, these bacteria also have the metabolic capacity to ferment citric acid and to produce diacetyl, a compound that has major impact on the flavor of cultured buttermilk. Diacetyl has a buttery aroma and flavor, and,...

Ethanol

The Embden-Meyerhoff-Parnas glycolytic pathway used by Saccharomyces cerevisiae and re-oxidize NAD via the lactate dehydroge-nase reaction. In contrast, in S. cerevisiae, this is done via a two-step series of reactions, in which pyruvate is first decarboxylated by pyruvate decarboxylase, generating acetalde-hyde and CO2. Next, the acetaldehyde is reduced by one of several NADH-dependent alcohol dehydroge-nases to form ethanol and oxidized NAD. The net effect, then, of glycolytic...

H h

Oenococcus, the malate permease is a uniporter, whereas in lactococci and lactobacilli, uptake of malate is mediated by an antiporter that exchanges an incoming malic acid for an outgoing lactic acid. No energy is spent for malate transport in either system. The exchange reaction, however, is not electroneu-tral.This is because one extracellular molecule of malic acid, carrying a net electric charge of -2, is exchanged for one of lactic acid that carries a net charge of only -l.This charge...

Swo

Xylose metabolism (A) and catabolite repression (B) of the xylose operon in Tetragenococcus halophilus. The xylose metabolic pathway consists of a transporter, an isomerase, and a kinase, encoded by xylE, xylA and xylB, respectively. The product of this pathway, xyulose phosphate, then feeds directly into the pentose phosphoketolase (PK) pathway. Expression of the xyl operon is mediated by positive (+) and negative ( ) regulation. During active growth on glucose, the glycolytic...

1

General steps for manufacture of hard cheeses. large U.S. manufacturers to use pasteurized milk for most cheeses, even those that are aged. Pasteurization, however, not only kills pathogens and undesirable spoilage bacteria, but it also inactivates much of the endogenous microflora and enzymes ordinarily present in raw milk. Since the microflora and enzymes both contribute to the overall flavor and texture properties of the finished cheese, especially if the cheese is aged, quality...

Light Golden Amber Dark

Types of malt used in brewing. Shown (from left to right) are four types of malt, ranging from light to dark. These malts are used to make beers with similar colors. Figure courtesy of Rich Chapin (Empyrean Ales, Lincoln, Nebraska) and John Rupnow (University of Nebraska). products ranging from a very fine to very coarse grind. Prior to milling, the malt is surrounded by a tough husk, which separates from the grain during milling, but generally is only partially degraded. The...

Dutchtype Cheeses

Among the most pleasant-tasting, colorful, and microbiologically complex cheeses are the so-called Dutch-type cheeses, of which Edam and Gouda are the most well-known. In fact, there are comparable cheeses produced throughout the world, using similar manufacturing procedures. Although eyes are usually present in these cheeses, there are fewer of them and they are much smaller than in Swiss cheese.The texture and flavor is also completely different from Swiss these cheeses are softer, with a...

Functionality

Most fermented foods are quite different, in terms of their functionality, from the raw, starting materials. Cheese, for example, is obviously functionally different from milk. However, functional enhancement is perhaps nowhere more evident than in bread and beer.When humans first collected wheat flour some 10,000 years ago, there was little they could do with it, other than to make simple flat breads. However, once people learned how to achieve a leavened dough via fermentation, the...

Mixing

The shredded and salted cabbage is then placed into tanks and mixed well to distribute the salt.As noted above, mixing is an important step, because localized regions within the rather heterogenous material may contain more or less than the 2.25 salt that was added to the bulk mixture. Within those pockets, therefore, it is entirely possible that the salt concentration may vary considerably, perhaps by as much as 0.1 . This may result in either too little or too much inhibitory control over the...

Meat

Of the ingredients listed above, the main ingredient is obviously the meat, which contributes not only the protein and the bulk of the product matrix, but also the fat, which provides much of the flavor.The fat-containing cuts usually are chopped or ground separately from the leaner portions to impart a desired appearance and flavor.The grind also affects texture and accordingly determines the type of product. For example, some sausages (e.g., Plockworst) have large visible fat particles,...

Glyceraldehyde3P

Mannitol formation in Leuconostoc. Phosphorylated glucose and fructose are metabolized by the heterofermentative (i.e., phosphoketolase) pathway. The reactions leading to lactic acid (from glyceralde-hyde-3-P) are not shown. Only the relevant enzymes are indicated enzymes for all other reactions are given in Chapter 2. P Phosphate. Adapted from Salou et al., 1994 Appl. Environ. Microbiol. 60 1459-1466. depleted suggests that some might be formed indirectly from glucose (following...

Squeezing out water

Once milk is transformed from a liquid into a solid (actually a gel), the next goal is to remove water.The first step involves increasing the surface area of the single large gel mass by cutting it into literally millions of smaller cubes of curd (e.g., 1 m3 of a cheese gel cut into 1 cm3 particles yields 106 such curd particles). Because the distance the water molecules must travel (from the interior of the gel to the outside environment) decreases as the curd size decreases, this step has the...

Manufacturing Principles

Like so many fermented foods, the first cheese made by human beings was almost certainly a result of an accident. Some wandering nomad, as the legend goes, filled up a pouch made from the stomach of a calf or cow with a liter or two of fresh milk.After a few hours, the milk had turned into a solid-like material, and when our would-be cheese maker gave the container a bit of a shake, a watery-like fluid quickly sep arated from the creamy white curd.This moderately acidic, pleasant-tasting curd...

Postfermentation

The fermentation is considered complete when the target acidity is reached and the yogurt is cooled quickly to below 4 C. In fact, for all practical purposes, cooling is really the only way to arrest the fermentation and stop further acid production. Cup-set yogurt must be very carefully moved to coolers (0 C to 4 C) to avoid agitation which may disturb the gel, resulting in syneresis. For Swiss style yogurt, where the fermentation occurs in a vat, the yogurt is typically stirred and cooled in...

References

Parolari. 2002.Validation of manufacturing process to control pathogenic bacteria in typical dry fermented products. Meat Sci. 62 323-329. Cook, P.E. 1995. Fungal ripened meats and meat products, p. 110-129. In G. Campbell-Platt and P.E. Cook (ed.), Fermented Meats. Blackie Academic and Professional (Chapman and Hall). Fern ndez, M., J.A. Orda ez,J.M. Bruna, B. Herranz, and L. de la Hoz. 2000. Accelerated ripening of dry fermented sausages. Trends Food Sci. Tech-nol. 11...

Wine Fermentation

I do like to think about the life of wine, how it is a living thing. I like to think about the year the grapes were growing, how the sun was shining that summer or if it rained . . . what the weather was like. I think about all those people who tended and picked the grapes, and if it is an old wine, how many of them must be dead by now. I love how wine continues to evolve, how every time I open a bottle it's going to taste different than if I opened it on any other day. Because a bottle of wine...

Sugar transport

As shown in Figure 8-7, glucose and fructose are both transported by common hexose transporters. Genetic evidence has revealed that there may actually be as many as twenty such transporters in S. cerevisiae. Although it is not known how different these transporters are to one another, they all transport their substrates

Production and Consumption

Most wines are made in temperate climates, particularly those areas near oceans or seas. About 75 of all wine is made in the Mediterranean areas of Europe (Table 10-1). France, Italy, and Spain are the largest producers, and are responsible for more than half of the nearly 27 billion liters of wine produced from around the world. Not surprisingly, these countries also devote the most acreage to grape production. However, several relatively new entrants into the global wine market have made a...

Lactobacillus

The genus Lactobacillus consists of more than eighty species (Figure 2-6). In the last decade, microbial taxonomists have been very busy, proposing and validating new taxa. In one single month (January 2005), seven new species and subspecies were described in the published literature. About all that is common to the species within this genus is that they are all non-sporing rods, but even this description is not wholly satisfactory. There are species that appear rather short (< 1.5 m),...

P

Phospho- L- CoA transacetylase pi acetaldehyde U- NADH + H dehydrogenase S- . nad Figure 2-11. The phosphoketolase pathway used by heterofermentative lactic acid bacteria. 48 Microbiology and Technology of Fermented Foods Box 2 3. The Heterolactic Fermentation Dealing with Pyruvate Lactic acid bacteria, as previously noted, are either homofermentative, heterofermentative, or facultative heterofermentative (where both pathways are present). However, even obligate homofermentative strains have...

Packaging and processing

In the United States, commercial products are usually thermally processed, much like other high-acid foods at about 75 C, prior to packaging in cans or jars. Such products are essentially commercially sterile and are stable at room temperature. There is also a market for non-pasteurized, refrigerated sauerkraut that is packaged in glass jars or sealed plastic bags (polybags). These products also have a long shelf-life, provided antimycotic agents, such as benzoate and sulfite salts, are added...

L

2Refers to the general properties of the genus some exceptions may exist 3Species of Lactobacillus may be homofermentative,heterofermentative,or both 4This phenotype is variable, depending on the species 5Some species produce D-,L-, or a mixture of D- and L-lactic acid. 2Refers to the general properties of the genus some exceptions may exist 3Species of Lactobacillus may be homofermentative,heterofermentative,or both 4This phenotype is variable, depending on the species 5Some species produce...