The effect of probiotic‐fermented soy milk on enhancing the NO‐mediated vascular relaxation factors

BACKGROUND: Soy milk is one of the common soy‐based foods in Asia. In this study the effects of soy milk fermented with selected probiotics on nitric oxide (NO)‐mediated vascular relaxation factors in cell model systems were investigated. RESULTS: Soy milk fermented with Lactobacillus plantarum TWK10 or Streptococcus thermophilus BCRC 14085 for 48 h showed a greater transformation of glucoside isoflavones to aglycone isoflavones (P < 0.05). An increase in aglycone isoflavones in ethanol extracts from fermented soy milk stimulated NO production and endothelial NO synthase (eNOS) activity in human umbilical vein endothelial cells. It also had a stimulating effect on superoxide anion scavenging and prostaglandin E₂ production. In addition, it enhanced mRNA expression of the E‐prostanoid 4 receptor in rat thoracic aorta smooth muscle cells. Moreover, a small amount of O induced by water extracts from fermented soy milk at low concentration (1 mg mL^?1) increased the content of calcium ions and activated eNOS, thereby promoting NO production and the coupling state of eNOS. CONCLUSION: Soy milk fermented with selected probiotics promotes the relaxation factors of vascular endothelial cells and can be applied in the development of functional foods. © 2012 Society of Chemical Industry     

Co-encapsulation of probiotics with prebiotics on alginate matrix and its effect on viability in simulated gastric environment

Two potential probiotic strains namely Staphylococcus succinus (MAbB4) and Enterococcus fecium (FIdM3) selected from previous probiotic property studies were co-encapsulated with complementary prebiotics. Two different prebiotics selected by in vitro fermentation viz. sugarbeet and chicory were separately encapsulated with both the strains in 2 g/100 mL alginate and were tested for the efficiency in improving the viability compared to free cells under in vitro acidic conditions. Results indicated significant improvement (P < 0.05) in survival of co-encapsulated cells when exposed to acidic (pH 2.0–3.0) and bile (0.3, 0.6 and 0.8 g/100 mL) conditions. The encapsulated cells showed about 98.75–88.75% of survivability in simulated gastric environment. Viability was maintained throughout the storage period and ranges from 8.1 log cfu/mL (Colony Forming Unit) to 7.9 log cfu/mL for about a period of 30 days at 4 °C. Interestingly it is the first work to use oligosaccharides rich carbohydrate source as such in encapsulation and was found to have an improved survival rate of probiotic strains along with alginate.     

Effect of addition of inulin and galactooligosaccharide on the survival of microencapsulated probiotics in alginate beads coated with chitosan in simulated digestive system,yogurt and fruit juice

Galactooligosaccharides (GOS) and inulin were added during microencapsulation of Lactobacillus acidophilus 5 and Lactobacillus casei 01 in alginate beads coated with chitosan at the concentrations of 0, 0.5, 1.0 and 1.5%. Addition of prebiotics significantly (p < 0.05) increased the bead size by approximately 3.8%. The presence of GOS (0.3%) in the microencapsulation provided the best protection with only 3.1 and 2.9 logs reduction for L. acidophilus 5 and L. casei 01, respectively, after incubation in simulated gastric juice (pH 1.55), followed by simulate intestinal juice containing 0.6% bile salt. The viabilities of microencapsulated probiotics containing 1.5% GOS in commercial yogurt and orange juice were also performed at refrigerated storage for 4 weeks. In yogurt, the numbers of cells with GOS were higher than those of without GOS by approximately 1.1 and 0.4 logs for L. acidophilus 5 and L. casei 01, respectively. In orange juice, the numbers of cells with GOS were higher than those of without GOS by approximately 0.5 and 0.4 logs for L. acidophilus 5 and L. casei 01, respectively. The numbers of probiotic bacteria were maintained above the recommended therapeutic minimum (10⁷ cfu g⁻¹ or mL⁻¹ of product) throughout the storage in both products.     

Impact of inulin and okara on Lactobacillus acidophilus La-5 and Bifidobacterium animalis Bb-12 viability in a fermented soy product and probiotic survival under in vitro simulated gastrointestinal conditions

The effect of inulin and/or okara flour on Lactobacillus acidophilus La-5 and Bifidobacterium animalis Bb-12 viability in a fermented soy product (FSP) and on probiotic survival under in vitro simulated gastrointestinal conditions were investigated throughout 28 days of storage at 4 °C. Employing a 2² design, four FSP trials were produced from soymilk fermented with ABT-4 culture (La-5, Bb-12, and Streptococcus thermophilus): FSP (control); FSP-I (with inulin, 3 g/100 mL of soymilk); FSP-O (with okara, 5 g/100 mL); FSP-IO (with inulin + okara, ratio 3:5 g/100 mL). Probiotic viabilities ranged from 8 to 9 log cfu/g during the 28 days of storage, and inulin and/or okara flour did not affect the viability of La-5 and Bb-12. Bb-12 resistance to the artificial gastrointestinal juices was higher than for La-5, since the Bb-12 and La-5 populations decreased approximately 0.6 log cfu/g and 3.8 log cfu/g, respectively, throughout storage period. Even though the protective effect of inulin and/or okara flour on probiotic microorganisms was not significant, when compared to a fresh culture, the FSP matrix improved Bb-12 survival on day 1 of storage and may be considered a good vehicle for Bb-12 and could play an important role in probiotic protection against gastrointestinal juices.     

The effect of pH on the formation of aroma compounds produced by heating a model system containing l-ascorbic acid with l-threonine/l-serine

The identification of aroma compounds, formed from the reactions of l-ascorbic acid with l-threonine/l-serine at five different pH values (5.00, 6.00, 7.00, 8.00, or 9.55) and 143 ± 2 °C for 2 h, was performed using a SPME–GC–MS technique, and further use of LRI. The results showed 35 aroma compounds. The reaction between l-ascorbic acid and l-threonine/l-serine led mainly to the formation of pyrazines. Many of these were alkylpyrazines, such as 2-methylpyrazine, 2,5-dimethylpyrazine, 2-ethylpyrazine, 2-ethyl-6-methylpyrazine, 2-ethyl-5-methylpyrazine, 3-ethyl-2,5-dimethylpyrazine, 2,3-diethyl-5-methylpyrazine, and 3,5-diethyl-2-methylpyrazine; other compounds identified were furans and aldehydes. More volatiles were generated in l-ascorbic acid with l-threonine systems than in l-ascorbic acid with l-serine systems. The studies showed that furans, such as furfural, 2-furanmethanol, benzofuran, 2,5-furandicarboxaldehyde and 2-furfurylfuran were formed mainly at acidic pH. In contrast, higher pH values could promote the production of pyrazines.