Alginate beads and apple pieces as carriers forSaccharomyces cerevisiaevar. boulardii, as representative of yeast functional starter cultures

Microencapsulating Alginate-Based Polymers for Probiotics Delivery Systems and Their Application

Probiotics exhibit many health benefits and a great potential for broad applications in pharmaceutical fields, such as prevention and treatment of gastrointestinal tract diseases (irritable bowel syndrome), prevention and therapy of allergies, certain anticancer effects, and immunomodulation. However, their applications are limited by the low viability and metabolic activity of the probiotics during processing, storage, and delivery in the digestive tract. To overcome the mentioned limitations, probiotic delivery systems have attracted much attention. This review focuses on alginate as a preferred polymer and presents recent advances in alginate-based polymers for probiotic delivery systems. We highlight several alginate-based delivery systems containing various types of probiotics and the physical and chemical modifications with chitosan, cellulose, starch, protein, fish gel, and many other materials to enhance their performance, of which the viability and protective mechanisms are discussed. Withal, various challenges in alginate-based polymers for probiotics delivery systems are traced out, and future directions, specifically on the use of nanomaterials as well as prebiotics, are delineated to further facilitate subsequent researchers in selecting more favorable materials and technology for probiotic delivery.

Probiotic and Potentially Probiotic Yeasts-Characteristics and Food Application

Probiotics are live microorganisms which when administered in adequate amounts confer a health benefit on the host. Besides the well-known and tested lactic acid bacteria, yeasts may also be probiotics. The subject of probiotic and potentially probiotic yeasts has been developing and arising potential for new probiotic products with novel properties, which are not offered by bacteria-based probiotics available on the current market. The paper reviews the first probiotic yeast Saccharomyces cerevisiae var. boulardii, its characteristics, pro-healthy activities and application in functional food production. This species offers such abilities as improving digestion of certain food ingredients, antimicrobial activities and even therapeutic properties. Besides Saccharomyces cerevisiae var. boulardii, on this background, novel yeasts with potentially probiotic features are presented. They have been intensively investigated for the last decade and some species have been observed to possess probiotic characteristics and abilities. There are yeasts from the genera Debaryomyces, Hanseniaspora, Pichia, Meyerozyma, Torulaspora, etc. isolated from food and environmental habitats. These potentially probiotic yeasts can be used for production of various fermented foods, enhancing its nutritional and sensory properties. Because of the intensively developing research on probiotic yeasts in the coming years, we can expect many discoveries and possibly even evolution in the segment of probiotics available on the market.

Alginate- and Gelatin-Coated Apple Pieces as Carriers for Bifidobacterium animalis subsp. lactis DSM 10140

Fruit and vegetables are considered good natural supports for microorganisms; however, probiotics could cause negative changes on some organoleptic and sensory traits. Thus, the main topic of this paper was the design of coated apple chips as carriers for probiotics with a high level of sensory traits. The research was divided into two steps. First, four functional strains (Limosilactobacillus reuteri DSM 20016, Bifidobacterium animalis subsp. lactis DSM 10140, and Lactiplantibacillus plantarum c16 and c19) were immobilized on apple pieces through dipping of fruit chips in probiotic suspensions for different contact times (from 15 to 30 min) and stored at 4°C for 12 days. Periodically, the viable count was assessed. As a result of this step, a contact time of 15 min was chosen because it assured an optimal deposition of microorganisms. In the second step, apple pieces inoculated with B. animalis subsp. lactis DSM 10140 were coated with alginate and gelatin and stored at 4 and 8°C for 10 days; pH, microbiological counts, color (browning index), and sensory scores were evaluated. Bifidobacterium animalis DSM 10140 exerted a negative effect on apple chips and cause a significant browning; however, the use of coating counteracted this phenomenon. In fact, coated chips showed higher sensory scores and lower browning index. In addition, gelatin showed better performances in terms of probiotic viability, because at 8°C, a significant viability loss of B. animalis DSM 10140 (1.2 log cfu/g) was found on alginate-coated chips. Gelatin-coated apple pieces with B. animalis subsp. lactis DSM 10140 could be an attractive functional food for a wide audience, although further investigations are required on in vivo effects of this product after consumption.

Microencapsulation of Saccharomyces cerevisiae into Alginate Beads: A Focus on Functional Properties of Released Cells

Five yeast strains (four wild Saccharomyces cerevisiae strains and a collection strain-S. cerevisiae var. boulardii) were encapsulated in alginate beads. Encapsulation yield was at least 60% (100% for some strains) and yeasts survived in beads for 30 days at 4 °C, although the viability was strongly affected during storage at 25 °C (3 log reduction after 7 days). The kinetic of cell release was studied under static and dynamic conditions, but the results suggest that, after 48 h, beads contained a high number of yeasts. Thus, their use is advisable as re-usable carriers of starter cultures or as a vehicle of probiotics into the gut. Finally, some functional properties (biofilm formation, hydrophobicity, auto-aggregation, survival during the transit into the gut) were evaluated on yeasts released by beads to assess if microencapsulation could negatively affect these traits. The results showed that yeasts' entrapment in beads did not affect probiotic properties.

Immobilization of Saccharomyces cerevisiae on Apple Pieces to Produce Cider

Three yeasts (Saccharomyces cerevisiae var. boulardii, a commercial probiotic yeast; S. cerevisiae W13, a wild yeast able to remove ochratoxin A; and S. cerevisiae 17, a wild yeast with promising probiotic traits) were screened for their ability to adhere on apple pieces as a function of different contact times (15–30 min). Then, apple pieces were stored at 4 °C for 15 days, and the viable count of yeasts was periodically assessed. Yeasts were able to adhere on apple pieces after 15 min (7 log cfu/g) and retained their viability throughout the refrigerated storage. In a second step, apple pieces with S. cerevisiae W13 were used to produce cider on a small scale. The variables under investigation were (a) the recycling of pieces up to 10 times and (b) the preliminary storage of pieces at 4 °C before use. Pieces used immediately after yeast immobilization could be successfully used again 10 times and gained a fermentation performance (in terms of yeast amount in cider and ethanol after 24 h) similar to that achieved by free cells. In addition, the preliminary storage of pieces at 4 °C did not affect their performances as reusable starter carriers.

Viability of Lactobacillus plantarum on Fresh-Cut Chitosan and Alginate-Coated Apple and Melon Pieces

There is an increasing trend toward foods with probiotics; the awareness of healthy diet and wellbeing is the leading cause of this increase. As a result, food producers and stakeholders require new probiotic products. The increased incidence of lactose intolerance and the new lifestyles (vegan and vegetarian styles) have led to a renewed interest in non-dairy probiotic carriers. The use of biopolymeric matrices to develop active food packaging carrying probiotics has been studied and proposed as an alternative method to design new solutions. The main topic of this paper was the design of fresh-cut fruits (apples and melons) as carriers for a promising Lactobacillus plantarum; fruit pieces were coated with either alginate or chitosan. Apple (Granny Smith) and melon pieces (Cucumis melo, var. Cantalupensis) were preliminary treated with an anti-browning solution (citric and ascorbic acids). Then, fruit pieces were dipped in a solution containing L. plantarum c19 (9 log cfu/ml) and coated with alginate or chitosan. Samples without probiotic and/or coatings were used as controls. All samples were stored at 4°C for 14 days under air or modified atmosphere (65% N2, 30% CO2, and 5% O2); the following analyses were done: pH, color, O2, and CO2 in the head space, microbiology (mesophilic bacteria, lactic acid bacteria, yeasts, and molds). The most important results can be summarized as follows: (a) Alginate coating showed better performances than chitosan-coating, as it did not affect the viability of L. plantarum. (b) The inoculation of probiotics in the controls negatively affected the color, but the coating was able to counteract this effect. This paper supports the combination of edible coatings and probiotic as a promising way to design new fruit-based functional foods; further investigations are required to study the effect of this combination on the sensory scores.

Application of Saccharomyces cerevisiae var. boulardii in food processing: a review

Probiotics are increasingly being added to food in order to develop products with health-promoting properties. Particularly, Saccharomyces cereviceae var. boulardii yeast is recently being investigated like a starting-culture for development of functional and probiotic foods. Although the literature is abundant on the beneficial effects of S. boulardii on health, slight information is available on the effects of supplementing this probiotic to food systems. The aim of this paper is to examine the applications of S. boulardii to different food matrices and its implication in food processing (stability, sensorial properties and other technological implications) and the concomitant effects on nutrition and health.