Survival of Lactobacillus acidophilus and Bifidobacterium animalis ssp. lactis in stirred fruit yogurts

The effect of commercial fruit preparations (mango, mixed berry, passion fruit and strawberry) on the viability of probiotic bacteria, Lactobacillus acidophilus LAFTI^® L10 and Bifidobacterium animalis ssp. lactis LAFTI^® B94 in stirred yogurts during storage (35 days) at refrigerated temperature (4 °C) was evaluated. The results showed that addition of either 5 or 10 g/100 g fruit preparations had no significant (p>0.05) effect on the viability of the two probiotic strains except on L. acidophilus LAFTI L10 yogurt with 10 g/100 g passion fruit or mixed berry. After the addition of fruit preparation, 96% of the yogurts incorporated with fruit preparation did not exhibit a greater loss in the viability of probiotic bacteria compared to plain yogurt during the storage period. A correlation between the post-storage pH in yogurts and the survival of probiotic bacteria was observed. All the yogurts, however, contained the recommended levels of (10⁶-10⁷ cfu/g) probiotic bacteria at the end of 35-day shelf life.     

Effect of calcium alginate and resistant starch microencapsulation on the survival rate of Lactobacillus acidophilus La5 and sensory properties in Iranian white brined cheese

Two types of probiotic cheese, with free and microencapsulated bacteria, were manufactured in triplicate under the same conditions. The number of viable cells during 182 days of storage in refrigerated conditions was evaluated. The number of viable cells of Lactobacillus acidophilus was reduced significantly from day 28 to day 182 of storage period in both types of cheese, but reduction in the cheese containing free cells (5.1 ± 0.67 log cfu g⁻¹) was significantly p < 0.05 higher than the cheese containing microencapsulated cells (11.00 ± 0.58 log cfu g⁻¹). The results showed that, microencapsulation in calcium alginate gel and resistant starch was able to increase the survival rate of L. acidophilus La5 in Iranian white brined cheese after 6 months of storage.     

Survival of Lactobacillus casei,Lactobacillus plantarum and Bifidobacterium bifidum in free and microencapsulated forms on Iranian white cheese produced by ultrafiltration

Survival of probiotic strains Lactobacillus casei ( ATCC 39392 ), Lactobacillus plantarum ( ATCC 8014 ) and Bifidobacterium bifidum ( ATCC 29521 ) was investigated either in microencapsulated or in free form in the Iranian white cheese produced by ultrafiltration technique. The results indicated that the survival of encapsulated probiotic bacteria was higher than free cells. Both free and microencapsulated forms were successful in keeping counts of L. casei, L. plantarum and B. bifidum in the cheese high enough for the therapeutic minimum (10⁶–10⁷ cfu/g) after 60 days. Addition of probiotic adjunct also did not alter the chemical composition, but pH was lower in probiotic cheeses.     

Microencapsulation of Lactobacillus acidophilus La-5 by spray-drying using sweet whey and skim milk as encapsulating materials

The aim of this study was to evaluate the effect of encapsulating material on encapsulation yield, resistance to passage through simulated gastrointestinal conditions, and viability of Lactobacillus acidophilus La-5 during storage. Microparticles were produced from reconstituted sweet whey or skim milk (30% total solids) inoculated with a suspension of L. acidophilus La-5 (1% vol/vol) and subjected to spray-drying at inlet and outlet temperatures of 180°C and 85 to 95°C, respectively. The samples were packed, vacuum-sealed, and stored at 4°C and 25°C. Encapsulation yield, moisture content, and resistance of microencapsulated L. acidophilus La-5 compared with free cells (control) during exposure to in vitro gastrointestinal conditions (pH 2.0 and 7.0) were evaluated. Viability was assessed after 0, 7, 15, 30, 45, 60, and 90 d of storage. The experiments were repeated 3 times and data were analyzed by ANOVA and Tukey test for the comparison between means. The encapsulating material did not significantly affect encapsulation yield, average diameter, or moisture of the particles, which averaged 76.58 ± 4.72%, 12.94 ± 0.78 μm, and 4.53 ± 0.32%, respectively. Both microparticle types were effective in protecting the probiotic during gastrointestinal simulation, and the skim milk microparticles favored an increase in viability of L. acidophilus La-5. Regardless of the encapsulating material and temperature of storage, viability of the microencapsulated L. acidophilus La-5 decreased on average 0.43 log cfu/g at the end of 90 d of storage, remaining higher than 10⁶ cfu/g.     

Survival of probiotic microflora in Argentinian yoghurts during refrigerated storage

The survival of Bifidobacterium bifidum BBI and Lactobacillus acidophilus LAI in reduced-fat (liquid) and full-fat (set) yoghurts produced with two commercial lactic starter cultures (SID and SISD) was investigated. The viability of the probiotic bacteria was also assayed in milk acidified with lactic acid at different pH values. Samples were stored at 5°C for up to 4 weeks. There was a great variability in the survival ability of the probiotic cultures in the two yoghurt types. L. acidophilus LAI demonstrated, in general, a lower resistance to the yoghurt environment than B. bifidum BBI. On the other hand, the full-fat yoghurt was a more inhibitory medium than the reduced-fat one, especially for B. bifidum BBI. Regarding the lactic starters used, the results showed that the culture SISD was clearly more inhibitory for both probiotic organisms than the culture SID. The loss of cell viability in yoghurt samples was different (higher in some cases and lower in others) from that due to lactic acid only. In general, pH values of 4.5 or lower jeopardised the cell viability of the probiotic organisms in yoghurt stored at 5°C. This work shows the importance of selecting a suitable combination of probiotic strains and starter cultures when different yoghurt types are formulated.     

Influence of microencapsulation and transglutaminase on viability of probiotic strain Lactobacillus helveticus M92 and consistency of set yoghurt

The effect of microencapsulated probiotic Lactobacillus helveticus M92 cells and transglutaminase addition on the probiotic set yoghurt properties was investigated. Addition of probiotic bacteria, either free or microencapsulated in sodium caseinate, decreased the fermentation time and significantly enhanced the appearance and consistency of probiotic set yoghurt. Better survival of microencapsulated than free probiotic bacteria in produced yoghurts during storage, as well as during exposure to simulated gastrointestinal conditions, emphasises the efficiency of microencapsulation in the cell protection. Pretreatment of the milk with transglutaminase increased the gel strength and decreased the syneresis, which resulted in a better appearance and consistency of probiotic set yoghurts.     

Impact of Bifidobacterium animalis subsp. lactis BB-12 and, Lactobacillus acidophilus LA-5-containing yoghurt, on fecal bacterial counts of healthy adults

This randomized, placebo-controlled, double blind, parallel dose-response study investigated the impact of 4-week commercial yoghurt consumption supplemented with Bifidobacterium animalis subsp. lactis (BB-12) and Lactobacillus acidophilus (LA-5) on fecal bacterial counts of healthy adults. Fifty-eight volunteers were randomly assigned to three different groups: 1. placebo (no probiotic, no starter and no green tea extract); 2. Yoptimal (10⁹ cfu/100 g of BB-12 and LA-5 and 40 mg of green tea extract) and 3. Yoptimal-10 (10¹⁰ cfu/100 g of BB-12, 10⁹ cfu/100 g of LA-5 and 40 mg of green tea extract). These yoghurt products also contained Lactobacillus delbrueckii subsp. bulgaricus (10⁷ cfu/100 g) and Streptococcus thermophilus (10¹⁰ cfu/100 g). The quantitative PCR (qPCR) results showed that there were significant increases (P = 0.02) in bifidobacteria counts with the Yoptimal treatment as compared to baseline. The fecal numbers of B. animalis subsp. lactis and LA-5 significantly increased in the two probiotic treatments compared to the placebo treatment. Viable counts of fecal lactobacilli were significantly higher (P = 0.05) and those of enterococci were significantly lower (P = 0.04) after the intervention when compared to placebo. No significant difference was observed between treatments in volunteers' weight, waist girth, blood pressure, fasting plasma triglyceride and HDL-C concentrations, as well as cholesterol/HDL-cholesterol ratio. However, a significant increase in plasma cholesterol levels was observed in the placebo group (P = 0.0018) but the levels remained stable in the two probiotic yoghurt groups. These results show that probiotic strains supplemented in the form of yoghurt remain active during gut transit and are associated with an increase in beneficial bacteria and a reduction in potentially pathogenic bacteria. This trial was registered at clinicaltrials.gov as NCT00730626.     

The growth behaviour and enhancement of probiotic viability in bioyoghurt

The growth behaviour of Lactobacillus casei-01 and Bifidobacterium bifidum Bb-12 in bioyoghurt made with three different yoghurt starter cultures (YC-Fast 1, YC-380 and YC-180) and the enhancement of probiotic viability, were investigated. The titratable acidity (TA) increased rapidly in yoghurt samples made with YC-Fast 1. The fermentation times were 3, 3.5 and 4 h for bioyoghurts made with YC-Fast 1, YC-380 and YC-180, respectively. The total viable counts of L. casei and B. bifidum were the highest in bioyoghurt samples made with YC-180. Microencapsulation of L. casei and B. bifidum enhanced their viability and this technique can be used with normal yoghurt starter. Also, utilization of heat shock yoghurt starter enhanced the viability of probiotics.     

Improving the viability of Bifidobacterium bifidum BB-12 and Lactobacillus acidophilus LA-5 in white-brined cheese by microencapsulation

The viability of Bifidobacterium bifidum BB-12 and Lactobacillus acidophilus LA-5 microencapsulated by either an extrusion or an emulsion technique and used in white-brined cheese was monitored. Both microencapsulation techniques were effective in keeping the numbers of probiotic bacteria higher than the level of the therapeutic minimum (>10⁷ cfu g^?1). While the counts of probiotic bacteria decreased approximately 3 log in the control cheese in which probiotics were used as free cells, the decrease was more limited in the cheeses containing microencapsulated cells (approximately 1 log). Medium- and long-chain free fatty acid contents of the cheeses with immobilized probiotics were much higher than in the control cheese. Similarly, cheeses made with immobilized probiotics contained higher acetaldehyde and diacetyl levels than the control. Experimental cheeses containing microencapsulated probiotics were not different from the control cheese in terms of sensory properties.     

Optimisation of probiotic yoghurt production containing Zedo gum

A Box‐Behnken design was applied to optimise the viability of Lactobacillus acidophilus and Bifidobacterium bifidum in probiotic yoghurt containing a novel exudative Zedo gum. The effect of incubation temperature, probiotic inoculation rate, storage time and Zedo gum concentration on quality indices of the yoghurt were explored. With respect to probiotics viability, probiotic inoculation rate was the most important factor followed by the storage time. Zedo gum did not show any significant effect on probiotics viability. The optimum conditions of probiotic yoghurt production were as follows: probiotic inoculation level, 12.8 g/100 kg of milk; incubation temperature, 41.6 °C; and Zedo gum concentration, 0.13%.     

Probiotic viability and storage stability of yogurts and fermented milks prepared with several mixtures of lactic acid bacteria

Currently, the food industry wants to expand the range of probiotic yogurts but each probiotic bacteria offers different and specific health benefits. Little information exists on the influence of probiotic strains on physicochemical properties and sensory characteristics of yogurts and fermented milks. Six probiotic yogurts or fermented milks and 1 control yogurt were prepared, and we evaluated several physicochemical properties (pH, titratable acidity, texture, color, and syneresis), microbial viability of starter cultures (Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus) and probiotics (Lactobacillus acidophilus, Lactobacillus casei, and Lactobacillus reuteri) during fermentation and storage (35 d at 5°C), as well as sensory preference among them. Decreases in pH (0.17 to 0.50 units) and increases in titratable acidity (0.09 to 0.29%) were observed during storage. Only the yogurt with S. thermophilus, L. delbrueckii ssp. bulgaricus, and L. reuteri differed in firmness. No differences in adhesiveness were determined among the tested yogurts, fermented milks, and the control. Syneresis was in the range of 45 to 58%. No changes in color during storage were observed and no color differences were detected among the evaluated fermented milk products. Counts of S. thermophilus decreased from 1.8 to 3.5 log during storage. Counts of L. delbrueckii ssp. bulgaricus also decreased in probiotic yogurts and varied from 30 to 50% of initial population. Probiotic bacteria also lost viability throughout storage, although the 3 probiotic fermented milks maintained counts ≥10⁷ cfu/mL for 3 wk. Probiotic bacteria had variable viability in yogurts, maintaining counts of L. acidophilus ≥10⁷ cfu/mL for 35 d, of L. casei for 7 d, and of L. reuteri for 14 d. We found no significant sensory preference among the 6 probiotic yogurts and fermented milks or the control. However, the yogurt and fermented milk made with L. casei were better accepted. This study presents relevant information on physicochemical, sensory, and microbial properties of probiotic yogurts and fermented milks, which could guide the dairy industry in developing new probiotic products.     

Açai pulp addition improves fatty acid profile and probiotic viability in yoghurt

The effects of açai pulp addition and different probiotic bacteria on the fatty acid profile of stirred yoghurt were examined. Skim milk was divided into two groups: one containing açai pulp and another without the fruit. Batches were inoculated with yoghurt starter culture and divided into five groups according to probiotic addition. Counts of viable microorganisms were measured at days 1, 14 and 28 of cold storage. Fatty acid profile was determined by gas chromatography at day 1. Açai pulp favoured an increase in Lactobacillus acidophilus L10, Bifidobacterium animalis ssp. lactis Bl04 and Bifidobacterium longum Bl05 counts at the end of 4 weeks of cold storage. This study demonstrated that açai pulp addition increased monounsaturated and polyunsaturated fatty acid contents in probiotic yoghurt and enhanced the production of α-linolenic and conjugated linoleic acids during fermentation of skim milk prepared with B. animalis ssp. lactis Bl04 and B94 strains.     

Use of gases to improve survival of Bifidobacterium bifidum by modifying redox potential in fermented milk

The aim of this work was to study the effect of the oxidoreduction potential, modified using gas, on the growth and survival of a probiotic strain, Bifidobacterium bifidum, and 2 yogurt strains, Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus. Three fermented milks were manufactured with an initial oxidoreduction potential value adjusted to +440 mV (control milk), +350 mV (milk gassed with N₂), and −300 mV [milk gassed with N₂ plus 4% (vol/vol) H₂ (N₂-H₂)]. Acidification profiles, growth during milk fermentation and survival during storage at 4°C for 28 d were determined. This study showed that fermented probiotic dairy products made from milk gassed with N₂ and, more particularly, those made from milk gassed with N₂H₂ were characterized by a significant increase in B. bifidum survival during storage without affecting the fermentation kinetics and the survival of Strep. thermophilus and L. delbrueckii ssp. bulgaricus.     

The Microstructure and Physicochemical Properties of Probiotic Buffalo Yoghurt During Fermentation and Storage: a Comparison with Bovine Yoghurt

The physicochemical and rheological properties of yoghurt made from unstandardised unhomogenised buffalo milk were investigated during fermentation and 28 days of storage and compared to the properties of yoghurt made from homogenised fortified bovine milk. A number of differences observed in the gel network can be linked to differences in milk composition. The microstructure of buffalo yoghurt, as assessed by confocal laser scanning microscopy (CLSM) and cryo scanning electron microscopy (cryo-SEM), was interrupted by large fat globules and featured more serum pores. These fat globules have a lower surface area and bind less protein than the homogenised fat globules in bovine milk. These microstructural differences likely lead to the higher syneresis observed for buffalo yoghurt with an increase from 17.4 % (w/w) to 19.7 % (w/w) in the weight of whey generated at days 1 and 28 of the storage. The higher concentration of total calcium in buffalo milk resulted in the release of more ionic calcium during fermentation. Gelation was also slower but the strength of the two gels was similar due to similar protein and total solids concentrations. Buffalo yoghurt was more viscous, less able to recover from deformation and less Newtonian than bovine yoghurt with a thixotropy of 3,035 Pa.s^?1 measured for buffalo yoghurt at the end of the storage, at least four times higher than the thixotropy of bovine yoghurt. While the titratable acidity, lactose consumption and changes in organic acid concentrations were similar, differences were recorded in the viability of probiotic bacteria with a lower viability of Lactobacillus acidophilus of 5.17 log (CFU/g) recorded for buffalo yoghurt at day 28 of the storage. Our results show that factors other than the total solids content and protein concentration of milk affect the structural properties of yoghurt. They also illustrate the physicochemical reasons why buffalo and bovine yoghurt are reported to have different sensory properties and provide insight into how compositional changes can be used to alter the microstructure and properties of dairy products.     

Novel probiotic-fermented milk with angiotensin I-converting enzyme inhibitory peptides produced by Bifidobacterium bifidum MF 20/5

In previous research, we have demonstrated that Bifidobacterium bifidum MF 20/5 fermented milk possessed stronger angiotensin converting enzyme (ACE) inhibitory activity than other lactic acid bacteria, including Lactobacillus helveticus DSM 13137, which produces the hypotensive casokinins Ile-Pro-Pro (IPP) and Val-Pro-Pro (VPP). The aim of this study is to investigate the ACE-inhibitory peptides released in B. bifidum MF 20/5 fermented milk. The novel ACE-inhibitory peptide LVYPFP (IC₅₀ = 132 μM) is reported here for the first time. Additionally, other bioactive peptides such as the ACE-inhibitor LPLP (IC₅₀ = 703 μM), and the antioxidant VLPVPQK were identified. Moreover, the peptide and amino acid profiles, the ACE-inhibitory activity (ACEi), pH, and degree of hydrolysis of the fermented milk were determined and compared with those obtained in milk fermented by L. helveticus DSM 13137. The sequences of the major bioactive peptides present in fermented milk of B. bifidum and L. helveticus were identified and quantified. B. bifidum released a larger amount of peptides than L. helveticus but no IPP or VPP were detected in B. bifidum fermented milk. Also the lactotripeptide concentrations and ACEi were higher in L. helveticus fermented milk when the pH was maintained at 4.6. This may represent a technical advantage for B. bifidum that reduces the pH at a slow enough rate to facilitate the peptide generation without the need for pH control. Thus these findings show the potential for the use of this probiotic strain to produce fermented milk with a wider range of health benefits including reduction of blood pressure.     

Bifidobacterium Bb-12 microencapsulated by spray drying with whey: Survival under simulated gastrointestinal conditions,tolerance to NaCl,and viability during storage

Bifidobacterium Bb-12 was microencapsulated by spray drying with whey. This present work investigated the survival of these microcapsules under simulated gastrointestinal conditions, as well as their tolerance to NaCl and their viability during storage. The results showed a small decrease in the viability of microencapsulated Bifidobacterium at low pH. In relation to the exposure of Bifidobacterium to bile, microencapsulation with whey did not protect the probiotic cells; however, the viability of the microcapsules remained >6 log cfu/g, even after 24 h of incubation at the highest bile concentration analyzed. No growth was noted with either the free cells or the microencapsulated cells on MRS-LP with NaCl. The viability of the microcapsules stored at 4 °C remained high and constant for 12 weeks. When the microcapsules were added to a dairy dessert, the probiotic count remained above 7 log cfu/g for 6 weeks. Therefore, whey is a promising encapsulating agent for Bifidobacterium Bb-12.     

Manufacture of Turkish Beyaz cheese added with probiotic strains

The survival of the probiotic strains Lactobacillus fermentum (AB5-18 and AK4-120) and Lactobacillus plantarum (AB16-65 and AC18-82), all derived from human faces, was investigated in Turkish Beyaz cheese production. Three batches of Turkish Beyaz cheese were produced: one with the test probiotic culture mix (P), another with a commercial starter culture mix including Lactoccocus lactis subsp. cremoris, Lactococcus lactis subsp. lactis (C) and the third with equal parts of the commercial starter culture mix and test probiotic culture mix (CP). The cheeses were ripened at 4 °C for 120 days and the viability of cultures was determined monthly. Cheese samples were analyzed for total solids, fat in solids, titratable acidity, pH, salt in total solids, proteolysis, sensory evaluation, aroma compounds and biogenic amines. While initial lactic acid bacteria load in P cheese was 2.7 × 10⁹ at the beginning, it was 7.42 × 10⁷ cfu/g at the end of 120 days of ripening. The results showed that test probiotic culture mix was successfully used in cheese production without adversely affecting the cheese quality during ripening. The chemical composition and sensory quality of P cheeses were also comparable with C cheeses. The present study indicates that probiotic cultures of human origin are feasible for Turkish Beyaz cheese production.     

Preparation and properties of probiotic concentrated yoghurt (labneh) fortified with conjugated linoleic acid

Milk of high conjugated linoleic acid (CLA) level (1.25 g per 100 g milk fat) was produced by inclusion of fish oil and rousted soy bean in the ration of Holstein cows as compared to 0.55 g per 100 g milk fat in the milk of animals receiving control diet. Milk of normal (control) and high CLA content (treatment) was spray‐dried. Labneh was made from 20 g L^?1 reconstituted milk using 3 mL per 100 mL yoghurt starter and 2 mL per 100 mL of probiotic cultures of Lactobacillus casei or Lactobacillus acidophilus. The control (C) and high CLA (T) labneh were analysed chemically and microbiologically, and their viscosities were determined during cold storage for 15 days. The fat content of labneh of high CLA was less than that of the control, but the total solids (TS) were unaffected by the CLA level. Labneh made with Lb. acidophilus had lower TS and higher acidity, exopolysaccharides and acetaldehyde contents and viscosity than that made with the use of Lb. casei. Labneh from the different treatments retained high counts of the added probiotic (>10⁸ cfu g^?1) throughout the storage period. The storage period had significant effects on all parameters determined.     

Effect of microencapsulation and resistant starch on the probiotic survival and sensory properties of synbiotic ice cream

Two types of synbiotic ice cream containing 1% of resistant starch with free and encapsulated Lactobacillus casei (Lc-01) and Bifidobacterium lactis (Bb-12) were manufactured. The survival of L. casei and B. lactis were monitored during the product’s storage for 180 days at −20 °C. The viable cell number of L. casei and B. lactis in the free state in prepared ice cream mixture was 5.1 × 10⁹ and 4.1 × 10⁹ CFU/mL at day one and after 180 days storage at −20 °C, these numbers were decreased to 4.2 × 10⁶ and 1.1 × 10⁷ CFU/mL, respectively. When we encapsulated the mentioned probiotic bacteria in calcium alginate beads, the probiotic survival raised at rate of 30% during the same period of storage at same temperature. In general, the results indicated that encapsulation can significantly increase the survival rate of probiotic bacteria in ice cream over an extended shelf-life. The addition of encapsulated probiotics had no significant effect on the sensory properties of non-fermented ice cream in which we used the resistant starch as prebiotic compound.     

Evaluation of the effect of supplementing fermented milk with quinoa flour on probiotic activity

In this work, we investigated the effect of supplementing fermented milk with quinoa flour as an option to increase probiotic activity during fermented milk production and storage. Fermented milk products were produced with increasing concentrations of quinoa flour (0, 1, 2, or 3 g/100 g) and submitted to the following analyses at 1, 14, and 28 d of refrigerated storage: postacidification, bacterial viability, resistance of probiotics to simulated gastrointestinal (GI) conditions, and adhesion of probiotics to Caco-2 cells in vitro. The kinetics of acidification were measured during the fermentation process. The time to reach maximum acidification rate, time to reach pH 5.0, and time to reach pH 4.6 (end of fermentation) were similar for all treatments. Adding quinoa flour had no effect on fermentation time; however, it did contribute to postacidification of the fermented milk during storage. Quinoa flour did not affect counts of Bifidobacterium animalis ssp. lactis BB-12 or Lactobacillus acidophilus La-5 during storage, it did not protect the probiotic strains during simulated GI transit, and it did not have a positive effect on the adhesion of probiotic bacteria to Caco-2 cells in vitro. Additionally, the adhesion of strains to Caco-2 cells decreased during refrigerated storage of fermented milk. Although the addition of up to 3% quinoa flour had a neutral effect on probiotic activity, its incorporation to fermented milk can be recommended because it is an ingredient with high nutritive value, which may increase the appeal of the product to consumers.