Olive paste as vehicle for delivery of potential probiotic Lactobacillus plantarum 33

Use of probiotic bacteria and consumes in large — in novel foods to provide beneficial health effects has attracted an increasing interest by the food industry and fermented olives are an excellent example of a new generation of those foods from plant origin so as to assure maximum viability by the time of ingestion during processing and storage of food products, as well as during transit through the gastrointestinal tract.Our study focused on production, characterization and assessment of efficacy of microencapsulation upon survival of probiotic strains and sensory properties of the final olive paste throughout refrigerated storage. Microencapsulation appears to be an effective technique for strain survival, depending on the operating temperature and experimental results on tolerance to gastrointestinal-like conditions, and ability to adhere to intestinal epithelium is thereby presented and discussed. The sensory panel rated all experienced matrices as good, including overall acceptance without significant preference between them. However, the success of microencapsulation was more limited when incorporated into olive paste. Free cells of Lactobacillus plantarum 33 proved able to survive in olive paste during storage at refrigerated temperatures.     

Edible methylcellulose-based films containing fructo-oligosaccharides as vehicles for lactic acid bacteria

The goal of this work was to investigate the physicochemical properties of methylcellulose (MC) based films as stabilizers of two strains of lactobacilli: Lactobacillus delbrueckii subsp. bulgaricus CIDCA 333 and Lactobacillus plantarum CIDCA 83114. The incorporation of 3% w/v fructo-oligosaccharides (FOS) into the MC film formulation improved the viability of L. delbrueckii subsp. bulgaricus CIDCA 333 after film preparation. L. plantarum CIDCA 83114 was intrinsically more resistant as no viability loss was observed upon preparation of the films in the absence of FOS.Scanning electronic microscopy images also showed a good incorporation of microorganisms without affecting the homogeneity of the films. FTIR spectroscopy provided structural information about the bacteria-loaded films. Water sorption isotherms showed an impervious behavior at low a_w but on exceeding 0.7 of a_w the film started to dissolve and form syrup, causing a drastic drop of bacterial viability (log N/N₀ ≤ − 5). Dynamic mechanical analysis (DMA) demonstrated that the incorporation of microorganisms into the MC films had no effect on vitreous transition temperatures. FOS incorporated into the MC films had a plasticizing effect.Microorganism-loaded films were stored at relative humidities (RH) ranging from 11 to 75%. Both strains could be stored at 11% RH for 90 days. At 33 and 44% RH L. delbrueckii subsp. bulgaricus CIDCA 333 could be stored up to 15 days and L. plantarum CIDCA 83114 up to 45 days. At 75% RH only L. plantarum CIDCA 83114 could be equilibrated (log N/N₀: − 2.05 ± 0.25), but CFU/g films were undetectable after 15 days of storage.The results obtained in this work support the use of MC films containing FOS as a good strategy to immobilize lactic acid bacteria, with potential applications in the development of functional foods.     

Selective enumeration of probiotic microorganisms in cheese

Cheese is a dairy product which has a good potential for delivery of probiotic microorganisms into the human intestine. To be considered to offer probiotic health benefits, probiotics must remain viable in food products above a threshold level (e.g., 10⁶ cfu g⁻¹) until the time of consumption. In order to ensure that a minimal number of probiotic bacteria is present in the cheese, reliable methods for enumeration are required. The choice of culture medium for selective enumeration of probiotic strains in combination with starters depends on the product matrix, the target group and the taxonomic diversity of the bacterial background flora in the product. Enumeration protocol should be designed as a function of the target microorganism(s) to be quantified in the cheese. An overview of some series of culture media for selective enumeration of commercial probiotic cultures is presented in this review.     

Ingredient selection criteria for probiotic microorganisms in functional dairy foods

The selection of potentially probiotic microorganisms for use in functional dairy foods is reviewed. Two groups of selection criteria are distinguished encompassing technological and medico-scientific properties. The former ensure provision of viable cultures of the desired cell density that are robust to the intended product application, while the latter ensure that the culture provided possesses activity in terms of some specified nutritional/health benefit at a specified site in the gastrointestinal tract. It is concluded that an understanding of the scientific principles and mechanisms involved in probiotic activities in the human host is continuing to emerge. Further advances will require a concerted collaborative effort between medical, pharmacological, nutritional, microbiological and technological experts. These advances will improve the basis upon which potentially probiotic microorganisms are selected and delivered by functional foods in the diet for specified human nutritional/health benefits .     

Development and characterisation of composite films made of kefiran and starch

In this study, new edible composite films were prepared by blending kefiran with corn starch. Film-forming solutions of different ratios of kefiran to corn starch (100/0, 70/30, 50/50, 30/70) were cast at room temperature. The effects of starch addition on the resulting films’ physical, mechanical and water–vapor permeability (WVP) properties were investigated. Increasing starch content from 0% to 50% (v/v) decreased the WVP of films; however, with further starch addition the WVP increased. Also, this increase in starch content increased the tensile strength and extensibility of the composite films. However, these mechanical properties decreased at higher starch contents. Dynamic mechanical thermal analysis (DMTA) curves showed that addition of starch at all levels increased the glass transition temperature of films. The electron scanning micrograph for the composite film was homogeneous, without signs of phase separation between the components. Thus, it was observed that these two film-forming components were compatible, and that an interaction existed between them.     

Sustainable starch-based edible films with agrifood residues as potential carriers for the probiotic Lactobacillus rhamnosus

Edible films are promising carriers for probiotics and can be composed by agrifood residues, which are usually rich in polymers and bioactive compounds. In this work, starch-based films were enriched with three types of agrifood residues (quince, potato and orange peels) and the incorporation of the probiotic Lactobacillus rhamnosus was studied, as well as the addition of inulin as a protective prebiotic. The resulting films were characterized in terms of mechanical properties, physicochemical properties, lactobacilli viability and microbiological properties. The mechanical properties of the films generally decreased with the introduction of L. rhamnosus, although this was highly dependent on the film composition. All films exhibited water vapor permeabilities in the typical range of starch-based films and were not greatly affected by the inclusion of probiotics. The loss of probiotic viability during films production was strongly related to the pH of the film-forming solutions. Films with agrifood residues had a slower loss of probiotic viability during storage, when compared to plain starch films, which may be explained by the presence of antioxidant compounds. Inulin was expected to improve viability, but this was not observed. Microbiological analysis showed that agrifood residues powders contained natural contaminant bacteria that were partially eliminated during film formation. Moreover, none of the target foodborne pathogens were detected in the analyzed samples. Overall, the results suggest that edible films containing agrifood residues can be a promising material for the delivery of probiotics and/or as primary packaging for some food products.     

Whey protein isolate- and carrageenan-based edible films as carriers of different probiotic bacteria

The use of polymer blends as carriers for probiotic cells or using multi-strain probiotic culture mixture in film formulations has a high potential to maintain the stability of probiotics throughout storage. In this study, the survival of Lactobacillus acidophilus, Lactobacillus plantarum, and mixed culture (Lactobacillus spp., Lactococcus spp., and Bifidobacterium spp.) in whey protein isolate (W), carrageenan (C), and W/C blend (W to C on a wt/wt basis at 100 to 0, 75 to 25, 50 to 50, and 0 to 100) films were investigated during 30 d of storage at 4 and 25°C. The water vapor, mechanical, optical, and morphological properties of film samples were also determined. A significant decrease in total lactic acid bacteria counts of all strains (5–6 log cfu/g in reduction) for W and C films was observed during storage at 25°C, whereas blended films had 2 to 3 log cfu/g reduction. The mixed culture-incorporated films had higher cell counts during all storage temperatures. The incorporation of probiotic bacteria significantly influenced the water vapor permeability and color values of films while decreasing tensile strength and elongation at break values. This study reveals that a multi-strain mixed culture presented more chance for survival inside the polymer matrix, especially when carbohydrate- and protein-based polymers were blended.     

Alginate- and gellan-based edible films for probiotic coatings on fresh-cut fruits

ABSTRACT:  Alginate- (2% w/v) or gellan-based (0.5%) edible films, containing glycerol (0.6% to 2.0%), N-acetylcysteine (1%), and/or ascorbic acid (1%) and citric acid (1%), were formulated and used to coat fresh-cut apple and papaya cylinders. Water vapor permeability (WVP) was significantly higher ( P < 0.05) in alginate films (0.30 to 0.31 × 10⁻⁹g m/Pa s m²) than in the gellan ones (0.26 to 0.27 × 10⁻⁹g m/Pa s m²). Addition of 0.025% (w/v) sunflower oil decreased WVP of gellan films (0.20 to 0.22 × 10⁻⁹ g m/Pa s m²). Water solubility of gellan and alginate films at 25 °C (0.47 to 0.59 and 0.74 to 0.79, respectively) and their swelling ratios (2.3 to 2.6 and 1.6 to 2.0, respectively) indicate their potential for coating high moisture fresh-cut fruits. Fresh-cut apple and papaya cylinders were successfully coated with 2% (w/v) alginate or gellan film-forming solutions containing viable bifidobacteria. WVP in alginate (6.31 and 5.52 × 10⁻⁹g m/Pa s m²) or gellan (3.65 and 4.89 × 10⁻⁹ g m/Pa s m²) probiotic coatings of papaya and apple, respectively, were higher than in the corresponding cast films. The gellan coatings and films exhibited better water vapor properties in comparison with the alginate coatings. Values > 10⁶ CFU/g B. lactis Bb -12 were maintained for 10 d during refrigerated storage of fresh-cut fruits, demonstrating the feasibility of alginate- and gellan-based edible coatings to carry and support viable probiotics on fresh-cut fruit.     

Identification of probiotic microorganisms in South African products using PCR-based DGGE analysis

Probiotic microorganisms in commercial yoghurts and other food products are currently identified by traditional methods such as growth on selective media, morphological and biochemical characteristics. In this study, PCR-based DGGE analysis was used for the rapid and accurate identification of probiotic microorganisms from South African yoghurts and lyophilized preparations in capsule and tablet form. To identify the microorganisms present in these products, the DGGE profiles obtained were compared to two reference markers (A and B) composed of five lactobacilli and seven Bifidobacterium species, respectively. The results obtained were confirmed by species-specific PCR, as well as sequence analyses of unknown bands not present in the reference markers. It was found that only 54.5% of the probiotic yoghurts contained the microorganisms stated on the label compared to only a third (33.3%) of the lyophilized probiotic products. Some Bifidobacterium species were incorrectly identified and various microorganisms were detected that were not listed on the label. Sequence analyses confirmed the presence of Streptococcus spp. other than the yoghurt starter, Streptococcus thermophilus, in some of these products and in some instances label information was vague and non-scientific. PCR-based DGGE analyses proved to be a valuable culture-independent approach for the rapid and specific identification of the microbial species present in South African probiotic products.     

Edible table (bio)spread containing potentially probiotic Lactobacillus and Bifidobacterium species

A prototype of a reduced fat (60% w/w) edible table biospread, with an added viable, nongrowing, mixed-strain and potentially probiotic culture was developed. Conventional commercial aqueous-phase ingredient and reduced fat spread processing technologies were modified to achieve acceptable strain viability ( ≥   10⁵ cfu/mL) during scraped-surface heat exchange emulsion processing and biospread shelf life. The modifications consisted of:

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   spilt-stream pasteurization of the aqueous and lipid phases (thereby obviating the need for in-line pasteurization of the water-in-oil emulsion during processing);

       
  
  

Fermented coconut jelly as a probiotic vehicle,physicochemical and microbiology characterisation during an in vitro digestion

There is little information on the survival of probiotics in plant-based foods after simulated gastric and intestinal conditions, likewise the microstructure arrangement in the no-dairy fermented food. This work aimed to study if the agar–agar in a fermented coconut jelly confers protection to probiotics, phenolic and antioxidant compounds during in vitro digestion. Samples containing higher agar–agar amounts tend to retain (P < 0.05) antioxidant and phenolic compounds in their network better, even after the in vitro digestion. Also, a compact and homogeneous microstructure was observed by the Confocal Laser Scanning Microscopy. The texture profile analysis shows that 1% of agar samples presented the maximum hardness (P < 0.05) due to more bonding points and intermolecular interactions. Finally, the survival of probiotics remained above the recommended values (10⁶–10⁷ CFU g⁻¹) after the in vitro digestion of a product with probiotic potential.     

可食性膜及其在食品工业中的应用

主要介绍可食性膜的概念和性质及其在食品工业中的主要应用。     

Edible films produced from agrifood by-products and wastes

This study aims to develop edible films using agrifood by-products (pumpkin seeds, broken rice and orange pectin) and wastes (quince peel, potato peel, potato pulp, orange peel, pumpkin peel). The physicochemical characteristics of the films were investigated, including their mechanical and barrier properties. Higher amounts of plasticizer induced poorer mechanical and barrier properties in the films. The most promising ones were obtained with orange pectin, broken rice and pumpkin peel, with water contact angles (WCA) between 48° and 57°, maximum water vapor transmission rate and water vapor permeability of 575 g.m⁻².d⁻¹ and 108 × 10⁻¹² g.Pa⁻¹.s⁻¹.m⁻¹, respectively, Young's modulus between 350 and 800 MPa, maximum tensile strength between 9.0 and 26.25 MPa, and elongation at break between 2.28 and 9.3%. Orange pectin and broken rice are promising raw materials since they led to higher WCA, better barrier and mechanical properties. Broken rice and quince peel can be good substitutes for commercial starch and glycerol, respectively. Agro-industrial by-products and wastes revealed potential for the production of sustainable edible films.     

明胶/淀粉可食性复合膜研究进展

介绍了明胶、淀粉的结构特点以及作为可食性膜的优缺点,并将明胶、淀粉共混作为复合型可食膜,探讨了增塑剂、增强剂以及相分离等因素对其性质的影响.     

A washed-curd goat's cheese as a vehicle for delivery of a potential probiotic bacterium: Lactobacillus delbrueckii subsp. lactis UO 004

This study characterizes the probiotic properties of Lactobacillus delbrueckii subsp. lactis UO 004 and examines its suitability for making cheese. This strain was isolated from infant feces and shows interesting features, such as acid and bile tolerance, adherence to intestinal epithelial cells, and inhibition of the growth of certain enteropathogens, that support its potential use as a probiotic strain. In this regard, the suitability of a washed-curd cheese (Vidiago type) made with goat's milk as a delivery system for this probiotic strain was assessed. Lactobacillus delbrueckii subsp. lactis UO 004 was incorporated into a starter culture (IPLA 001). Changes in the overall composition of control and experimental cheeses were determined during ripening through bacteriological, chemical, high-performance liquid chromatography, and gas chromatography analyses. Slight changes in the gross composition and appreciable differences in the flavor compounds profile were observed between control and experimental cheeses. This strain was capable of surviving at high cell numbers (10(8) to 10(9) CFU/g) in cheeses after 28 days of ripening without adversely affecting sensory criteria or appearance of the cheese, thus satisfying the criteria for a probiotic food product.     

Agar films containing green tea extract and probiotic bacteria for extending fish shelf-life

A bioactive film composed of agar, incorporating green tea extract and probiotic strains (Lactobacillus paracasei L26 and Bifidobacterium lactis B94) was applied on hake fillets in order to evaluate the effect of the films during 15 days of storage. Hake was previously inoculated with Shewanella putrefaciens and Photobacterium phosphoreum (10³–10⁴ CFU/g) to simulate a spoilage process. The green tea and/or probiotic film provoked a reduction, particularly of H₂S-producing bacteria counts and total viable bacteria throughout the storage period. The probiotic strains added to the film could pass to the fish producing an increment of lactic acid bacterial counts, even in the presence of green tea extract. The effect of the films also caused a decrease in the indexes of fish quality (total volatile basic nitrogen (TVB-N), trimethylamine nitrogen (TMA-N) and pH). The total viable counts, H₂S-producing microorganisms and TVB-N were maintained below the limits of acceptability during 15 days for the fillet covered with the green tea + probiotic film, compared to the rest of the samples. Films with green tea and probiotic were able to extend shelf-life of hake at least for a week and increase the beneficial lactic acid bacteria in fish.     

Survival and sensory acceptability of probiotic microorganisms in a nonfermented frozen vegetarian dessert

Probiotic microorganisms were incorporated into a nonfermented, vegetarian frozen soy dessert at initial populations greater than 10⁶ cfu/g. The product was assessed for the survival of probiotic microorganisms and sensory acceptability. Lactobacillus acidophilus MJLA1, L. rhamnosus 100-C, L. paracasei ssp. paracasei 01, Bifidobacterium lactis BBDB2, B. lactis BB-12 all survived the 6 month storage trial at populations of 10⁷ cfu/g or greater. Saccharomyces boulardii 74012 did not retain sufficient viability, decreasing below the desirable level of 10⁶ cfu/g. To detect sensory differences, product containing L. acidophilus MJLA1, S. boulardii 74012 and an uninoculated control were stored for 0, 4 and 7 months and compared using triangle tests. Product inoculated with L. acidophilus MJLA1 could not be distinguished from the control sample. Product with S. boulardii 74012 differed from the control and L. acidophilus MJLA1 and developed undesirable flavours during storage. The frozen soy dessert was a suitable food for the delivery of bacterial probiotic strains with excellent viability and acceptable sensory characteristics.     

Ice-cream as a probiotic food carrier

Ice-creams are food products showing potential for use as probiotic vehicles, with the added advantage of being appreciated by people belonging to all age groups and social levels. However, the development of ice-creams containing probiotic bacteria requires the overcoming of certain technological intrinsic requirements related to their processing stages. The aim of the present paper was to review the technological parameters involved in the production of probiotic ice-creams. Although the application of probiotics in cheeses, and especially in fermented milks, has been widely explored in the literature, ice-cream is a relatively innovative matrix for the application of probiotics, and thus a review about its potential as probiotic food carrier could be very helpful.     

Edible films with anti‐Listeria monocytogenes activity

Edible films based on wheat gluten, gelatin and brea gum were prepared with incorporation of ca. 500 UA cm^?2 of enterocin with anti‐Listeria monocytogenes action, synthesised by Enterococcus faecium CRL1385. The analyses of the different edible films revealed that they did not show any significant changes in their functional and physicochemical features after the enterocin incorporation (P value < 0.05). Gelatin and brea gum films had a higher solubility in water than wheat gluten films. Listeria cell growth were not inhibited by edible matrices per se; while a similar inhibition to that of free enterocin was observed in gelatin films after 2 h and remained unchanged for the duration of the assay. Wheat gluten films showed a lower enterocin–matrix interaction and a limited bactericidal action was observed for 2 h, after which the activity disappeared. In contrast, brea gum was found to interact with the enterocin molecule inhibiting its anti‐Listeria activity. Edible gelatin and wheat gluten films with enterocin can be potentially used to control Listeria monocytogenes contamination in food products.