Yeasts as Functional Foods

Witkowska, I. Minmczuk-Chodakowska, and M.E. Zujko Department of Food Commodities Science and Technology, Medical University ofBialystok, Poland. 

FIGURE 26.1. Chanterelle (Cantherellus dbarius) ( 2012 Anna M. Witkowska). 

Yeasts are eukaryotie single-cellular organisms, which are not visible to the bare eye. Some yeasts, eommon in many sectors of the food industry, belong to the order Saccharomycetales, such as baking yeasts Sac-charomyces cerevisiae). Therefore, the term ys sts is often used as a S5monym of S. cerevisiae. Other Saccharomycetales, sueh as Saccharo-myces boulardii, are utilized for purposes of probiotic food production. 

---

Considering their nutritional and biological properties, mushrooms and yeasts are promising candidates for functional food manufacturing, as well as ingredients in the healthy food formulations. Health benefits from mushrooms and yeasts as functional foods are considerable and involve the prevention of degenerative diseases as atherosclerosis, cardiovascular disease, cancer, diabetes, as well as certain functional disorders. Functional foods were recently redefined as important sources in the prevention, management and treatment of chronic diseases of the modem age, and mushrooms and yeasts are well placed in this concept. 

Currently, chitosan has been approved as a food additive in Korea and Japan since 1995 and 1983, respectively (KFDA, 1995 Weiner, 1992), and is mostly applied as a food additive or preservative and as a component of packaging material. In addition, the antimicrobial characteristics of chitosan present a profitable potential for developing functional food ingredients however, they may prove to be useful in nutraceuticals for the ability to stimulate host defenses against a variety of bacteria, fungi, and yeast (Lim and Hudson, 2003). 

The main probiotic preparations available on the market are known as Lactic Acid Bacteria (LAB), for the most part represented by lactobacilli and bifidobacteria, which are important constituents, normally present, of the gastrointestinal microflora, and that produce lactic acid as a major metabolite. Moreover, also certain yeasts and bacilli are counted among probiotics. Table 37.3 reports the microorganisms recognized as probiotics and used in the production of functional foods. 

Coconut water is the liquid endosperm fluid of the coconut fruit which contains high amounts of essential nutrients and minerals. This endosperm fluid is a widely consumed as a beverage in many parts of the world as it provides hydration along with increased nutritional, health and medicinal benefits. In addition to being used as a medium constituent, it also acts as a natural biocatalyst One of the fermented products of coconut water, coconut water kefir, is made by fermenting coconut water with the kefir granules which contain essential lactic acid bacteria and yeast spp. known to have health benefits for a disease-free life. It has many applications in the food industry and functional food market It is used as one of the important constituents in a variety of products or can be consumed as-it-is . It is known to have no undesirable side effects and is said to improve digestioa This paper reviews the functional properties of coconut water, its applications in the food industry and recent advancements in this area. 

FIG. 15 A comprehensive stability map illustrating the general relationship between the occurrence of various reactions important in foods, as a function of water activity, superimposed on a sorption isotherm. M, mold Y, yeast B, bacteria. The isotherm is plotted as moisture content (left y axis) versus water activity, whereas all other curves are plotted as relative reaction rate (right y axis) versus water activity. Additional information corresponding to regions I, II, and III is given in Table IV. 

Tyramine acts as an indirect sympathomimetic to cause release of catecholamines from nerve terminals. It is present in a number of foods mature cheese, yeast extracts, some red wines, hung game, pickled herrings, broad bean pods. Normally, MAO-A in the intestinal mucosa will metabolise tyramine absorbed from the gut. In patients on the older MAOls, considerable amounts of tyramine will enter the circulation and this will lead to increased release of catecholamines stored in nerve terminals because the MAOI prevents their metabolism. For patients on RIMA drugs, high concentrations of tyramine can compete for MAO-A, thus mitigating some of the effects, and MAO-B is still available to metabolise noradrenaline (norepinephrine). MAO-B, however, has relatively much less effect on 5-HT and thus 5-HT function is still enhanced. 

---