1. Fermenting Foods: Rediscovering Nutritional and Healthy Living Benefits
Pamela Starke-Reed, Ph.D. Deputy Administrator, Agricultural Research Service Nutrition, Food Safety and Product Quality
United States Department of Agriculture, USA
Linda Duffy, Ph.D., MPH
Scientific Chair, Trans-NIH Division of Nutrition Research Coordination, Probiotics/Prebiotics WG Scientist Administrator, NCCIH National Institutes of Health, USA

2. Definition of Fermentation
What is fermentation? An anaerobic cellular process in bacteria, yeast or other microorganisms convert foods into simpler compounds and chemical energy (ATP) is produced.
Fermentation in food processing is the conversion of carbohydrates into alcohols and carbon dioxide or organic acids by yeast, bacteria or combinations of both.
What are fermented foods?
Foods processed for example, through lacto-fermentation wherein
natural bacteria feed on the sugar and starch, creating lactic acid.
This process biopreserves the food, creates beneficial enzymes, b-
vitamins, omega-3 fatty acids, and probiotic bacterial strains.
Biopreservation, as commented above, can be defined as the extension of shelf life and food safety by the use of natural or controlled microbiota and/or their antimicrobial compounds. One of the most common forms of food biopreservation is fermentation, a process based on the growth of microorganisms in foods, whether natural or added. Fermented foods are widely associated in dairy and cheese cultures and, currently, increasingly in specialty foods in other fermented products such as meat, spirits, vegetable products, and juices. The bacteria used are selected depending on food type with the aim of positively affecting the physical, chemical, and biological composition of foods, providing attractive flavor properties for the consumer. To be used as starter cultures, microorganisms must fulfil the standards of GRAS status and present no pathogenic nor toxigenic potential. In addition, use must be standardized and reproducible. For the starter cultures, generally LAB, metabolic activity, such as acid production in cheese, is of great technological importance, whereas antimicrobial activity is secondary. However, for the protective culture, associated with probiotic foods, generally LAB also, the objectives must always take into account an additional factor for safety as its implantation must reduce the risk of growth and survival of pathogenic microorganisms. An ideal probiotic strain would fulfil both the metabolic and antimicrobial traits.

3. FERMENTATION
Fermentation occurs when bacteria and enzymes convert carbohydrates into alcohol or organic acids, changing the flavour and texture of food and preserving it. The beneficial microorganisms eat up sugars (which is why many fermented foods taste sour) and inhibit the growth of harmful bacteria. This process occurs naturally in many foods under natural fermentation processes and humans have made use of it for thousands of years (for example, making yoghurt out of milk or alcohol from fruit). Before refrigerators, we would eat vegetables in season and ferment them for preservation for the winter.
Kimchi
Fermentation has been a part of diets around the world since ancient times, from kimchi – fermented vegetables eaten in Korea – to Northern Europe’s sauerkraut, to fermented soya beans in Japan. Kefir was originally preserved in goatskin pouches by shepherds in the Caucasus mountains. ‘Until 100 years ago, many of the foods we ate were fermented in some way and this made it easier to retain the balance of good bacteria in our bodies.

4. Two types of fermentation Lactic Acid Fermentation
Alcoholic vs
Lactic Acid Fermentation
When fermentation occurs, the sugars and carbohydrates in a food are converted into a new form. For example, fruit juice becomes wine, grains transform into beer, and vegetable sugars change into preservative organic acids that extend the shelf life of the vegetables. Sourdough also draws on fermentation, with the end result of a delicious homemade bread. As a process, fermentation multiplies vitamin C content and facilitates creating and absorption of group B vitamins. Vegetables are traditionally fermented with salt and water. When immersed in brine, any harmful bacteria are killed off, assuring that the food is preserved safely. At the same time, beneficial bacteria − particularly lactobacillus organisms − flourish and convert sugars in the food into lactic acid. This creates an acidic environment that discourages any harmful bacteria from proliferating. It's also what gives fermented veggies their signature pungent flavor.
Simply put, fermentation of vegetables happens when the natural bacteria in the vegetables break down the components of the vegetables into forms easier to digest and often more nutritious than the raw vegetable itself

5. Most fruits and vegetables contain toxic bioactive compounds
Most fruits and vegetables contain toxic bioactive compounds. These can be removed or detoxified by the action of microorganisms during fermentation process. Plant foods contain a series of compounds, which interfere with the assimilation of some nutrients and may confer toxic or undesirable physiological effects. Such antinutrients include oxalate, protease, and α-amylase inhibitors, lectins, condensed tannins, and phytic acid.

6. Fermentation Food Products and their Uses
Carbon dioxide – bread making using baker’s yeast
Alcohol – wine making and brewing using yeast
Lactic Acid – lactic acid bacteria ferment milk into products as yogurt; Sauerkraut, fermented cucumbers, and kimchi are the most studied lactic acid fermented vegetables.

7. Biopreservation in Different Food Products
Biopreservation of fermented foods depends on the biological activities of microflora that produce a range of metabolites to suppress the growth, proliferation and survival of food spoilage microorganisms and food-borne pathogens.
The term biopreservation is used in a broader sense than fermentation. Some biopreservative microorganisms may not ferment foods although they may produce inhibitory substances against pathogenic or spoilage microflora. Moreover, the new trend of using bacteriophages as biopreservatives also places biopreservation a step further ahead of traditional fermentation.
A cucumber, for example, can be pickled with vinegar or fermented without vinegar, using a salty brine instead. During fermentation, however, vinegar and other acids are produced, which is why fermented sauerkraut and pickles taste “vinegary.”
Lactic acid producing bacteria [LAB] play a critical role in the preservation and microbial safety of fermented foods, promoting the microbial stability of the final products of fermentation. Protection of foods is due to the production of organic acids, carbon dioxide, ethanol, hydrogen peroxide, and diacetyl antifungal compounds such as fatty acids or phenyllactic acid, bacteriocins, and antibiotics.
Bacteriocins can be used to confer a rudimentary form of “innate immunity to foodstuffs.” Bacteriocins are ribosomally synthesised, extracellularly released low molecular-mass peptides or proteins (usually 30–60 amino acids), which have a bactericidal or bacteriostatic effect on other [pathogenic] bacteria,
In the U.S., the use of bacteriocins and/or bacteriocin-producing strains of probiotic grade lactic acid bacteria [LAB] microbial cultures are of great interest and potential as many species have been classified as generally recognized as safe organisms and their antimicrobial products as biopreservatives. However, it is imminently important to continue to expand our understanding of the influences that environmental factors have on the implantation, survival, and safety of bacteriocinogenic producing strains and the functional activity of their bacteriocins, in order to quantitatively estimate their efficacy for future applications in food model systems and establish adequate means of safe application of these biopreservatives.

8. Origins of Some Fermented Foods
Approximate year
of introduction
Region
Mushrooms
Soy sauce
Wine
Fermented milk
Cheese
Beer
Bread
Fermented Meats
Sourdough bread
Fish sauce
Pickled vegetables
Tea
4000 BC
3000 BC
2000 BC
1500 BC
1000 BC
200 BC
China
China, Korea, Japan
North Africa, Europe
Middle East
North Africa, China
Egypt, Europe
Europe
Southeast Asia, North Africa
China, Europe
The earliest record of fermentation may date back as far as 6000 B.C. in the Fertile Crescent—and nearly every civilization since has included at least one fermented food in its culinary heritage. From Korean kimchi and Indian chutneys to the ubiquitous sauerkraut, yogurt and cheese, global cultures have crafted unique flavors and traditions around fermentation.
As world population increases, lactic acid bacteria [LAB] fermentation is expected to become an important role in preserving fresh vegetables, fruits, and other food items for feeding humanity in developing countries. However, several fermented fruits and vegetables products (Sauerkraut, Kimchi, etc] have a long history in human nutrition from ancient times.
Asian traditional fermented foods are generally fermented by LAB which are considered as the probiotic source of the food practice.
With the popularity and success of cabbages [e.g., Korea - kimchi, and German sauerkraut,) fermentation of many other traditional vegetables has emerged, such as cucumbers, beets, turnips, cauliflower, celery, radishes, and carrots.
The most reported fermented fruits and vegetables in modern diets are
Root vegetables: cabbages; carrots, turnips, beetroot, radishes, celeriac, and sweet potato
Vegetable fruits: cucumbers, olives, tomatoes, peppers, okra, and green peas .
Vegetables juices: carrot, turnips, tomato pulp, onion, sweet potato, beet, and horseradish
Fruits: apples, pears, immature mangoes, immature palms, lemons, and fruit pulps such as banana and berries.

9. Benefits of Fermentation
Raw material
Fermented food
Preservation
Milk
(Most materials)
Yoghurt, cheese
Enhancement of safety
Vinegar
Beer
Wine
Salami
Gari, polviho azedo
Soy sauce
Acid production
Acid and alcohol production
Production of bacteriocins
Removal of toxic components
Fruit
Barley
Grapes
Meat
Cassava
Soybean
Enhancement of nutritional value
One of the important outcomes of food fermentation is the enrichment of food with essential amino acids, vitamins, mineral and bioactive compounds.
Example ---- bitter varieties of cassava tubers contain a potentially poisonous substance that can be detoxified via lactic acid bacteria, as in gari and fufu, fermented cassava root products from Africa.
Bread
Kimchi, sauerkraut
Nata de coco
Bifidus milk, Yakult,
Acidophilus yoghurt
Improved digestibility
Retention of micronutrients
Increased fibre content
Synthesis of probiotic compounds
Wheat
Leafy veges.
Coconut
Milk

10. LACTOBACILLUS FERMENTATION
Lactic Acid Bacteria are the most widely studied group of microorganisms for biopreservation of foods
The genus Lactobacillus is a heterogeneous group of LAB with important application in food and feed fermentation. Lactobacilli are used as probiotics inoculants and as starters in fermented food .
Note for Pam --- Lactobacillus is generally divided into two groups depending on the ability of the sugar fermentation: homofermentative species, converting sugars mostly into lactic acid and heterofermentative species, converting sugars into lactic acid, acetic acid and CO2. LAB can influence the flavour of fermented foods in a variety of ways. During fermentation, lactic acid is produced due to the metabolism of sugars. As a result, the sweetness tastes will likely decrease as sourness increases .

11. Lactic Acid Bacteria
Lactic acid bacteria have been used to ferment or culture foods for at least 4000 years.
Examples: products like yogurt and cheese
Lactic acid content of fermented food product may enhance the utilization of calcium, phosphorus, and iron and also increase adsorption of iron and vitamin D. Fermented foods have a variety of enzymes and each enzyme can play a different role in increasing food quality.
Although challenges remain, it is possible that fermented foods, handed down for many generations, will play a major role in the global food industry.

12. Transit of Food Through the Human GIT
Fermented veggies are a potential source of replenishing commensal probiotic functional benefits.
Diagram shows overview of the relationship between transit of food through the human gastrointestinal tract and the digestion of nutrients in the small intestine and fermentation in the cecum and colon.
. In the small intestine, digestion occurs through the action of intrinsic enzymes, and nutrients are absorbed. Food components and endogenous secretions not absorbed in that viscus pass through the ileocecal valve and are fermented. Fermentation is high in the proximal large bowel as is the Short chained fatty Acids (SCFA) production.
Absorption of SCFA and of water and minerals (including calcium) is high in this viscus. On passage through the lower colon, fermentation declines through substrate depletion, and SCFA values fall. The distal large colon and rectum are the regions of the large bowel with the most limited supply of SCFA and are the site of most pathology. Bacteria and unfermented components of low fermentability are voided in the feces.
David L. Topping, and Peter M. Clifton Physiol Rev 2001;81:

13. Effects of Probiotic Bacteria and Yeast
Fermented vegetables are a potential way to add probiotic-grade commensal bacteria to your diet. Balacned microbial ecology the gut lining is essential so that harmful organisms and toxins do not pass into the bloodstream. Probiotics in the gut also work to prevent harmful bacteria from colonizing the GI tract by competing directly for space and crowding out pathogens and producing SCFAs and other beneficial substances.
In addition to ensuring safety and product integrity, the challenge in developing clinical recommendations for probiotics therapy is not a lack of scientific literature, but a lack of consolidated research and consistency across studies with respect to bacterial strains, dosages and populations, as to specific functional benefits.
Although documenting efficacy of probiotics is still emerging, a growing number of consumers and health-care professionals are interested in trying probiotics,” and that people might “also be interested in increasing the levels of live active cultures in their diet. Once consumed, LAB bacteria from fermented veggies have many potential benefits. Ongoing studies suggest probiotic LAB help synthesize vitamins, produce digestive enzymes, and aid with the absorption of nutrients such as calcium, magnesium, and iron. Beneficial bacteria help maintain the integrity of the gut barrier. \
Christina L. Ohland, and Wallace K. MacNaughton Am J Physiol Gastrointest Liver Physiol 2010; 298:G807-G819

14. Microbial Fermentation and Effects on Host Functional Properties
Diagram shows -----The microbiota induces host immune tolerance to
commensal bacteria directly via a microbe-associated molecular pattern
(MAMP) and polysaccharide (PSA) signaling, indirectly through the
production of short-chain fatty acids (SCFA) and potentially through
expression of epithelial intestinal alkaline phosphatase (IAP), which
detoxifies luminal lipopolysaccharides (LPS).
Probiotic grade LAB segmented filamentous bacteria (SFB) promote
Immune development of Th17 cells through epithelial cytokine production
and antigen presentation by dendritic cells (DC), and the community as a
whole is required for proper gut associated lymphoid tissue (GALT)
development.
SCFA also induce IgA and mucus secretion into the lumen, promote
epithelial barrier integrity, and prevent pathogen colonization. The
microbiota also participates in the formation of the active, secondary f
forms of bile acids.

15. Probiotic Benefits in Food Consumption Being Studied
The gut is the largest immune system in the body which is the first contact point for most antigenic and infective exposure, and having a favourable microbiota will have a positive influence on health, In studies to date, Probiotics and health claims are moving well beyond the gut but are defined as playing a major role in gastroenterology—inflammatory bowel disease, antibiotic associated diarrhea, infectious diarrhea, diverticular disease, celiac disease, irritable bowel syndrome, pancreatitis.
Even though it has been broadly studied that dairy fermented products are the best matrices for delivering probiotics, there is growing evidence of the possibility of obtaining probiotic foods from nondairy matrices. Several raw materials (such as cereals, fruits, and vegetables) have recently been investigated to determine their suitability for designing new, nondairy probiotic foods…
The gut is thought to play a key role in our immune system, too. ‘One theory is that a healthy gut releases cytokines, chemical messengers that regulate our inflammatory and immune responses,’
Probiotics are also known to have a hypocholesterolemic effect and helps to lower blood pressure.”
Researchers generally agree that even if a bacterial species has the potential to offer health benefits, it shouldn't be called a probiotic until the effects are demonstrated in studies to be of health benefit and safe use for human consumption. . This includes undefined bacteria present in fermented foods.

16. Functional Fermenting Foods Research
Sources of Prebiotics
Sources of Probiotics
The preferred source of any nutrient—of which probiotic bacteria are no exception—is natural food. Designer food’, ‘functional food’ and ‘fortified food’ are synonym, which refers to the food fortified or enriched with nutrient content already present in them or other complementary nutrient.
Fermented foods enriched with probiotic LAB strains play a promising role in biofortification strategies and offer potential for promoting health, improving nutrition and reducing the risk of various diseases worldwide. Usually, eight reasons considered as useful for fermented foods: (a) Fermented foods improve digestion, (b) fermented foods restore the proper balance of bacteria in the gut, (c) raw fermented foods are rich in enzymes, (d) fermented foods actually increase the vitamin content, (e) eating fermented foods help us to absorb the nutrients we are consuming. (f) fermented foods help to preserve it for longer period of time, (g) fermented food is inexpensive and (h) fermented food increases the flavor.
The greatest challenge to growth markets of enriched probiotic fermented foods, and assuring the view that certain antimicrobial factors are present [e.g., bacteriocins] , is product integrity and rigor of standardization in the methods used, the environment and the hygiene of the people that prepare them, that will determine the quality of the product.
According to the U.S. Centers for Disease Control, only one recent botulism poisoning in the U.S. has been recorded [home-fermented tofu-related]. Yet home-fermented tofu and other fermented bean products are the leading cause of botulism poisoning in China. Again, the proper food-safety precautions, chief among them sanitation, but also temperature controls, need to be strictly followed.

17. Probiotic Functional Foods
Fermentable Cabbage
Probiotic Functional Foods
In fresh cabbage, vitamin C is bound in the cellulose structure and various other molecules, and our digestive system is just not able to cleave it off and absorb it. Lots of it goes undigested and come out right out of you. So despite the fact that cabbage may be very rich in vitamin C, most of us will not be able to absorb. However, by fermenting the cabbage [sauerkraut; kimchi], all the vitamin C becomes bioavailable,”
Cabbage is high in anti-inflammatory properties, vitamins A and C. Cabbage also reduces lipids in the bloodstream. When cabbage is fermented into sauerkraut the fermentation process opens up the cell walls accessing a higher ratio of vitamins.
It has been said that sauerkraut has 200
times more vitamin C than the head of
cabbage before fermentation.
Beneficial functions of LAB {probiotic] microorganism in fermenting foods are improvement of bioavailability of minerals through the hydrolysis of phytate, folate biofortification and detoxification of mycotoxins due to surface binding capacity
cabbage
KIMCHI

18. Among the beneficial effect of fermented food which contains LAB probiotic organisms being studied for food safety and health effects in human consumption practices includes: improving intestinal tract health, enhancing the immune system, synthesizing and enhancing the bioavailability of nutrients, reducing symptoms of lactose intolerance, decreasing the prevalence of allergy in susceptible individuals, and reducing risk of certain cancers.
Healthy bacteria found in naturally fermented foods produce enzymes that can break down foods present in the intestines, thus making the nutrients easier absorption. Furthermore, the beneficial bacteria also produce vitamins such as the water soluble vitamin B and C, making the fermented food richer in nutrients. Yoghurt is a prime example. It is easier to digest than the milk it is made from, and richer in water soluble vitamins

19. Fermenting Foods Bio-Fortification as Alternative
Strategies for Improving Nutritional Status
Fermentation technologies play an important role in ensuring the food security of millions of people around the world, particularly marginalized and vulnerable groups. This is achieved in part through improved food preservation, increasing the range of raw materials that can be used to produce fermented food products and removing anti-nutritional factors that make food s unsafe to eat. Designer foods approach is one of the major strategies to reduce micronutrient deficiency in developing countries,
Probiotic enriched fermented and designer foods are produced by the process of fortification or nutrification. With the advances in the biotechnology, biofortification of foods using technologies fermentation procedures are being studied and of increasing interest to food safety and sustainability in global health. The ultimate acceptability and extensive use of functionally beneficial designer foods depend on appropriate safety regulation in the market by the regulatory authorities of the country and by creating consumer awareness about substantiated benefits/risks.
This includes i) evaluating the possible effects on biodiversity, the environment and food safety, ii) weighing the benefits of the product or process against its assessed risks, iii) monitoring the post-release effects of these products and processes to ensure their continued safety