Two potential probiotic yeasts Saccharomyces cerevisiae (strain KTP) and Issatchenkia occidentalis (ApC) were microencapsulated using maltodextrin and sucrose or sorbitol with an aim to improve its ...effectiveness by spray drying. Commercialized probiotic yeast Saccharomyces cerevisiae var. boulardii (NCDC 363) was used as a reference yeast in the study. The efficiency of the encapsulation was evaluated by yeast viability, and physical parameters such as yield, water activity, particle size and shape of the microcapsule. Furthermore, simulated gastrointestinal juice was used to estimate the protective effect of the matrix in the digestive system. Results indicated that sucrose or sorbitol incorporated maltodextrin microcapsules achieved 35–45% of increment in the viability of yeasts NCDC 363, KTP and ApC than maltodextrin alone encapsulated group. The encapsulated yeast was remarkably improved its growth in simulated gastrointestinal condition (32–64% in gastric and 46–80% in bile juice) as compared to the non-encapsulated yeast. However, we did not find any observable difference in growth among encapsulated groups in the gastrointestinal survival assay. The study provided an evidence for incorporation of sucrose and sorbitol enhance the maltodextrin encapsulation efficiency by spray drying.
•Sucrose and sorbitol enhanced the yeast survival in simulated gut system.•2% sucrose and sorbitol improved the yeast viability by spray drying.•The components did not alter the characteristics of maltodextrin encapsulation.
•DS-L. acidophilus protected L. acidophilus from simulated gastrointestinal juices.•DS-L. acidophilus was effective in enhancing the growth, intestine microflora and mucosal architecture of weaned ...pigs.•DS-L. acidophilus had better effects than DS, L. acidophilus or DS+L. acidophilus.
Diosmectite-Lactobacillus acidophilus composite (DS-L. acidophilus) was prepared by immobilization of L. acidophilus onto DS. The surival rate of L. acidophilus in DS-L. acidophilus were determined after simulated gastric juice and intestinal fluid. A total of 180 piglets, weaned at 21±1 d age, were used to investigate the effects of DS-L. acidophilus in intestinal function. The vivo trial included five groups: (1) control; (2) L. acidophilus; (3) DS; (4) DS-L. acidophilus; (5) The mixture of diosmectite and L. acidophilus (DS+L. acidophilus). The amount of DS or L. acidophilus in each group was equivalent. The results in vitro showed that DS-L. acidophilus increased (P<0.05) the survival rate of L. acidophilus in simulated gastric juice for 80min and intestinal fluid for 240min, as compared with the free L. acidophilus. The results in vivo showed that, as compared with control, DS-L. acidophilus increased (P<0.05) average daily gain, intestinal Lactobacillus, the ratio of villus height and crypt depth, the jejunal and colonic transepithelial electrical resistance. The DS-L. acidophilus addition decreased (P<0.05) the paracellular permeability of fluorescein isothiocyanate dextran 4kDa in jejunum and colon. However, DS, L. acidophilus or DS+L. acidophilus had no (P>0.05) effect. The results indicated that DS-L. acidophilus was more effective in improving growth performance and intestinal function of weaned pigs than DS, L. acidophilus or DS+L. acidophilus.
Cypermethrin is a common food contaminant and environmental pollutant that cause health threats to animals and humans. In this study, the characterization, mechanism, and application of cypermethrin ...removal by Saccharomyces cerevisiae were investigated. The binding of cypermethrin by the strains S. cerevisiae YS81 and HP was rapid and reached equilibrium at 2–8 h. The removal efficiency was dependent on incubation temperature and yeast concentration, whereas cypermethrin binding was not affected by pH. Heat and acid treatments enhanced the binding ability. Both strains survived in simulated digestion juices and removed cypermethrin effectively under simulated gastrointestinal conditions. Among the strains tested, the YS81 strain was the better candidate for cypermethrin concentration reduction. For the two S. cerevisiae strains, the biosorption kinetics and isotherm followed the pseudo-second-order model and Langmuir model well. The cell walls and the protoplasts were the main yeast cell components involved in cypermethrin binding. Fourier transformed infrared spectroscopy analysis revealed that –OH, –NH, –C–N, –COO−, and –C–O played a major role in binding cypermethrin. Inactive cells effectively removed cypermethrin from apple and cucumber juices and did not affect the physico-chemical properties. Therefore, S. cerevisiae strains YS81 and HP may be used for cypermethrin reduction in food or feed.
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•The cypermethrin binding ability is not dependent on the biomass viability.•The cell walls and the protoplasts play important roles in cypermethrin binding.•–OH, –NH, –C–N, –COO−, and –C–O groups participate in the adsorption.•S. cerevisiae is a novel promising biosorbent to reduce cypermethrin level in food and feed.
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.
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