Investigating the role of pre-acidification process in modulating buffering capacity and lactic acid bacteria viability in ultrafiltered milk

Objectives: The aim of this study was to investigate the conditions for viable lactic acid bacteria (LAB) cells and their heat-killed LAB, and the formulation as well as an alternative treatment to antibiotics to reduce infection, invasion and the inhibition of IL-8 secretion induced by S. choleraesuis for HT-29 cells. Methods: To examined the efficacy of live LAB and heat-killed products in (1) inhibiting Salmonella choleraesuis growth by the plate agar-well diffusion assay, (2) adhering to swine intestinal cells and human intestinal Caco-2 cell line, (3) inhibiting the invasion of HT-29 cell line by Salmonella choleraesuis, and (4) inhibiting Salmonella choleraesuis induced interleukin (IL)-8 secretion by HT-29 cells Results: The results indicated that viable LAB and heat-killed products significantly reduced S. choleraesuis infection, invasion in the HT-29 cell line, and had the adhesion ability of the LAB to the swine intestinal cells and human intestinal Caco-2 cell line. Both viable and heat-killed LAB powder possess an ability to reduce the S. choleraesuis induced interleukin (IL)-8 secretion by HT-29 cells, and viable bacteria powder products are the most effective. Conclusion: Both viable and heat-killed LAB powder products were potentially useful for the protection of the epithelial cells against Salmonella infection, invasion and the induced inflammation for swine and human.

Sourdough is made from water and wheat flour, fermented by lactic acid bacteria and yeast. Papaya can serve as a natural starter for producing sourdough. This study aims to assess the impact of drying on pH levels, total titratable acidity (% TTA), the viability of lactic acid bacteria (LAB), yeast viability, specific volume, and the texture profile of gluten and gluten-free bread. Three types of starters were used: P (fermented water from papaya and flour), G (fermented water from papaya, sugar, and flour), and W (mineral water and flour) to make type I sourdough (before drying). Type III sourdough (dried) was obtained using spray drying (S), cabinet drying (C), and freeze-drying (F). The pH, %TTA, LAB, and yeast viability were measured, while the specific volume and texture profiles of the breads were evaluated. Spray drying significantly affected the pH of the A sample and LAB viability in the W and G samples. Cabinet drying significantly affected the %TTA and yeast viability in the G sample. Freeze-drying significantly affected the LAB and yeast viability in the W and G samples, as well as yeast viability and %TTA in the P sample. Instant sourdough can be produced using spray, cabinet, or freeze drying and is suitable for making both gluten-containing and gluten-free bread. Variations in starter type and drying methods influence the bread's physical characteristics, including specific volume and texture profile. The drying methods significantly affected hardness, gumminess, chewiness, cohesiveness, springiness index, and resilience in both gluten-containing and gluten-free bread samples.

OBJETIVO: Foram avaliadas as características probióticas dos microorganismos utilizados no preparo de iogurte de soja suplementado com os prebióticos oligofrutose e inulina (frutooligossacarídeos), suas características físico-químicas, microbiológicas e índice de aceitação. MÉTODOS: A formulação contendo extrato de soja em pó, oligofrutose e inulina, obtida por fermentação durante seis horas, em estufa mantida à temperatura de 42ºC, foi caracterizada e comparada a uma formulação de iogurte de soja sem suplementação quanto à viscosidade, perfil de textura e características probióticas. RESULTADOS: O fermento misto utilizado no preparo do iogurte (Lactobacillus bulgaricus e Streptococcus thermophilus) apresentou resistência à bile e ao ácido. Os prebióticos mantiveram a viabilidade das bactérias láticas até o 28º dia de armazenamento, em nível superior ao necessário para caracterizar um alimento probiótico. O iogurte suplementado apresentou pH de 4,63 e acidez de 0,37%, maior viscosidade, coesividade e adesividade e menor dureza que o iogurte sem suplementação. O índice de aceitação do iogurte de soja suplementado com prebióticos foi de 71,20%. CONCLUSÃO: Lactobacillus bulgaricus e Streptococcus thermophilus são probióticos e frutooligossacarídeos são ingredientes que mantêm a viabilidade das bactérias láticas no iogurte de soja, propiciando a formulação de um produto com boa aceitabilidade.

An innovative milk-based functional product was developed to produce a quality and healthy animal product, such antioxidant-rich cheese. The study conducted to identify the chemical composition, lactic acid bacteria (LAB) viability, color characteristic, hardness, and stickiness cheese with cinnamon extract during storage. Material used were cow milk from UPT Ternak Perah Diponegoro University, cinnamon extract, animal rennet, and culture of Lactobacillus plantarum Kita-3 from Food and Nutrition Culture Collection (FNCC), Universitas Gadjah Mada. The research assessed experimentally using completely randomized design (CRD) with 4 treatments and 6 replications. Cheese was stored on refrigerator at 4-10°C and observed at 0, 10, and 20 days to determine titrated acididity (TA), water content (WC), free fatty acid (FFA), LAB viability, color characteristics, hardness, and stickiness. Treatments were addition of cinnamon extract 0% (P0), 3% (P1), 6% (P2), and 9% (P3). Data collected was analyzed by analysis of variance and continuing with duncan’s multiple range test. The addition of cinnamon were not affected (p>0.05) to TA and FFA at 0 day observation, WC, b*, stickiness at 0 and 20 days, and hardness at 10 days. Meanwhile, it affected significantly (p<0.01) to TA at 10 and 20 days, pH and LAB viability at all observation, WC at 10 days, FFA and hardness at 0 and 20, and stickiness at 10 days. In summary, the addition of cinnamon up to 9% could produce a good quality of cheese during storage.

The aim of this study was to adapt MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] colorimetric assay (MCA) (Wang et al., 2010) for determination of lactic acid bacteria cell count. Our study is helpful in developing protocols for measuring the viability of other lactic acid bacteria. We determined the cell concentration range which gives linear regression of CFU (colony forming units) and formazan production. In our experiment three authentic lactic acid bacteria strains were investigated: Lactobacillus rhamnosus VT1, L. plantarum 2142, and L. sakei DSM 2001. As data show beside the strain also the growth medium has influence on the MTT reduction activity, this means that for each special case separate calibration curve has to be prepared. Based on MTT reduction we also developed an improved microtiter plate assay which proved to be reliable for a rapid cell count determination. So our methods are only applicable for estimate cell number with fixed parameters, but under given circumstances they are fast and sensitive methods. With the modified methods we can rapidly measure the dehydrogenase enzyme activity of the lactic acid bacteria cells. With the microplate assay we can measure many conditions and strains at the same time.

Different impact of heat-inactivated and viable lactic acid bacteria of aquatic origin on turbot (Scophthalmus maximus L.) head-kidney leucocytes

This study aims to determine the effect of Lactobacillus casei and Ambon banana flour on the viability of lactic acid bacteria and inhibition of pathogens in yogurt. The studies used the Randomized Block Design (RBD) 2 factor, starter type and ambon banana flour concentration. The starters type consisting of Streptococcus thermophillus and Lactobacillus bulgaricus; S. thermophilus, L. bulgaricus and L. casei. The banana flour concentration consisting of 0; 2.5; 5.0; 7.5 and 10%. Analyzed used one-way ANOVA and continued with Duncan's Multiple Range Test. Variables observed including the viability of lactic acid bacteria, inhibition of pathogen (Escherichia coli and Staphylococcus aureus), and yogurt preference. The results showed that the addition of L. casei to yogurt cultures decreased the viability of lactic acid bacteria and inhibition of E. coli but increased inhibition of S. aureus. Increasing the concentration of banana flour causes increased viability of lactic acid bacteria, inhibiting against E. coli and S. aureus. The highest lactic acid bacteria viability has resulted in 10% banana flour concentration. Yogurt without the addition of banana flour cannot inhibit E. coli and S. aureus. Increasing the concentration of banana flour added to yogurt causes a decrease in preference.

Eucheuma cottoni is one of the most utilised marine commodities for carrageenan production. Carrageenan can also be used for probiotics production. This study aimed to obtain bacterial growth media with the highest probiotic activity before and after drying. The study consisted of several stages, include: pre-hydrolysis, hydrolysis with inactive enzymes, chemical and microbiological characterisation, drying with spray drying, and lactic acid bacteria (LAB) viability test. The results show that the untreated sample had the best results compared to that of the filtering and precipitation samples. The untreated sample had reducing sugar content of 0.35%, total sugar 2.81%, pH 5.37, total acid 0.147%, and total LAB of 8.2x108 CFU/mL. After drying with spray drying, the LAB viability reduced to 9.7x106 CFU/mL.

Boza is a traditional fermented cereal‐based beverage, which should be consumed within 3–5 days after production due to its short shelf‐life. Spray drying process is an excellent option to overcome this problem to make the product least perishable. The optimal spray drying conditions for boza powder production in a laboratory‐scale spray dryer were investigated using, Response Surface Methodology. Air inlet temperature and feed flow rate were the main parameters that affected the responses such as powder yield, moisture content, cell viability, particle size, and solubility. The optimum spray drying conditions were 148°C air inlet temperature, 9°C feed temperature, and 10 ml/min feed flow rate. At these optimum conditions, deviations between predictive and experimental values were found very low. A 1.5 log cfu/g reduction in lactic acid bacteria (LAB) viability was achieved, however instant properties of boza powder should be improved by agglomeration processes. Laboratory and pilot scales were also compared at the determined optimum drying conditions. Approximately 0.4 log cfu/g difference in LAB viability was observed between the two scales.Practical ApplicationsBoza is one of the most valuable fermented cereal products due to its high nutritional value. The short shelf life of Boza limits its consumption and makes it a seasonal product. Spray drying technology could provide overcome these challenges and improve the usability and durability of boza beverages. However, the quality of a spray‐dried product highly depends on process conditions. Therefore the effects of the spray drying process conditions on the physicochemical properties of boza powder and the scale‐up conditions were investigated for the first time in this study.

PurposeThe purpose of this paper is to evaluate the effect of green tea polyphenols addition on physicochemical, microbiological and bioactive characteristics of yogurt.Design/methodology/approachTwo incorporation methods of polyphenols were evaluated: direct addition or incorporated within protein particles of whey protein concentrate and gelatin. During yogurt’s shelf life, structure characteristics (water holding capacity, textural and rheological parameters), lactic acid bacteria (LAB) viability and polyphenols antioxidant activity were analyzed. Also, polyphenol bioaccesibility afterin vitrodigestion was evaluated.FindingsPolyphenols addition (by the two methods used) did not affect the dynamics of the fermentation process, nor the LAB viability during storage. The color parametera* for the yogurts with the highest polyphenol concentrations showed positive values (tending to red), but not visible to the naked eye. Because of the ability of polyphenols to interact with milk proteins, yogurts with polyphenols presented higher values in firmness and cohesiveness with respect to the control. Additionally, the incorporation of polyphenols in protein particles increased even more these parameters because of the higher protein content of these formulations. After simulated digestion, a high polyphenol bioaccesibility was observed, and the antioxidant activity was retained, which could be explained by the “protector” effect of the milk matrix.Practical implicationsYogurt supplementation with green tea polyphenols is feasible for the development of functional food. However, the use of protein particles would not provide an extra benefit because milk proteins already act as protective molecules of polyphenols.Originality/valueThis study shows not only the physico-chemical implications of including polyphenols in yogurt but also their bioaccesibility after anin vitrodigestion, revealing a suitable manner for delivery of antioxidants in a dairy product like yogurt.

This research aimed to analyze the viability of lactic acid bacteria in carrageenan fortified yogurt powder. This research was done in Laboratory of Food Chemistry and Nutrition Faculty of Animal and Agriculture and Laboratory of Integrated Diponegoro University. Yogurt was made using pasteurized fresh milk and inoculated with Lactobacillus bulgaricus and Streptococcus thermophillus. The incubation was set to 6 hour and followed drying in vacuum oven. Carrageenan 0.5% (w/v) was mixed prior to the drying. The all treatment was repeated 4 times. The viability of lactic acid bacteria in powdered yogurt was analysed during 10 days. The results of this research showed that carrageenan addition provide no noticeable effect to the viability in powdered yogurt during the ten days storage. The conclusion of this research was carrageenan may be used in powdered yogurt without provide any affect in the viability of lactic acid bacteria.

The tolerance of lactic acid bacteria (LAB) from kefir grains to gastrointestinal tract conditions was evaluated in vitro. The effects of pH values and bile salts on the viability of LAB were investigated. The results demonstrated that pH value showed a significant effect on the viability. The viable counts exhibited a reduction of 1.5 to 2 log cycles in 0.3% to 0.5% bile salts after 4 h. The viability of LAB exposure to sequential simulated gastric and intestinal juices was assessed by response surface model (RSM). RSM indicated that the gastric pH and gastric contact time significantly affected the viability (P < 0.05), while the effect of intestinal contact time was not significant. Moreover, RSM revealed the interactions of pH and gastric contact time, and of pH and intestinal contact time. The LAB cells, temporarily damaged by the low pH of gastric juice (pH < 2), could recover in the intestinal juice; and the longer the intestinal contact time, the higher the viability of LAB. RSM proved to be a useful and accurate method to predict the viability of LAB under certain laboratory conditions by the model validation. This study indicated that LAB from kefir grains exhibited excellent tolerance to sequential simulated gastrointestinal tract conditions, and that kefiran possessed a significant protective effect on LAB in hostile environments.

Chemoreaction drying using Calcium oxide (CaO) has potential to be applied due to its heatless effect and low cost. The aim of this research is to know the effect of CaO concentration upon chemoreaction drying on viability of lactic acid bacteria (LAB), as well as to know the effect of carboxyl methyl cellulose (CMC) as protecting agent on viability of LAB and to evaluate its application of that inoculums on fermented durian. The results showed that the higher concentration of CaO used, the faster velocity of drying. The highest viability of LAB (68%) was achieved by the treatment of CaO ratio and culture of 1:5. However, the LAB viability of this research was considered low indicated that it needs improvement in the further research. The CMC as protecting agent was able to increase viability of LAB compare to those without CMC treatment. Application of inoculums to tempoyak fermentation was comparable as it had highest sensorial score and total LAB compare to those without LAB inoculums in term of more acid. Keywords: Calcium oxide, chemoreaction, drying, tempoyak, viability.

Yoghurt is the product from coagulation of milk that is produced from fermentation process of lactic acid bacteria (LAB), Lactobacillus bulgaricus (LB) and Streptococcus thermophilus (ST). Usually during storage and distribution, the viability of LB and ST decrease. Marketing and distribution method which is done by small scale industry is using combination storage on coolbox with 15oC-20oC during 10 hours and followed by storage on refrigerator with 5oC during 14 hours. The purpose of the research observe the effect of storage time on such condition. The research purposed to observe the effect of storage time during distribution and marketing on the viability of Lactic Acid Bacteria (ST and LB) and acidity levels in black mulberry yogurt. The research based on RBD (Randomized Block Design) single factor: the long of storage during distribution and marketing (1; 5; 9; 13; 17 and 21 days) with 4 replications. The parameters observed were pH, total acid and viability LAB (ST and LB). The data obtained were analyzed statistically with Analysis of Variance (ANOVA) and Duncan Multiple Range Test (DMRT) (α = 0.05). The long of storage during distribution and marketing gave significant affect on the viability of lactic acid bacteria and the acidity of the black mulberry yogurt. The longer of storage time, the lower LAB viability and pH, but higher total acid. The value of black mulberry yoghurt ALT LAB after 21 days of storage 9.1484 log cfu / ml with a pH value of yogurt 3.814, acidity Soxhlet Henkel 95.03 oSH and total of lactic 2.14%. Black mulberry yogurt during 13 days of storage and distribution is qualified to SNI with 9.5148 ALT log cfu/mL and a total of lactid acid 1.97%.

Quantifying the viability of lactic acid bacteria using ratiometric fluorescence assays