Phytase activity of lactic acid bacteria and their impact on the solubility of minerals from wholemeal wheat bread

Abstract

The objective of this study was to determinate phytase activity of bacteriocins producing lactic acid bacteria previously isolated from spontaneous rye sourdough. The results show that the highest extracellular phytase activity produces Pediococcus pentosaceus KTU05-8 and KTU05-9 strains with a volumetric phytase activity of 32 and 54 U/ml, respectively, under conditions similar to leavening of bread dough (pH 5.5 and 30?°C). In vitro studies in simulated gastrointestinal tract media pH provide that bioproducts prepared with P. pentosaceus strains used in wholemeal wheat bread preparation increase solubility of iron, zinc, manganese, calcium and phosphorus average 30%. Therefore, P. pentosaceus KTU05-9 and KTU05-8 strains could be recommended to use as a starter for sourdough preparation for increasing of mineral bioavailability from wholemeal wheat bread.     

Effect of the Incorporation of Different Freeze-Dried Cultures on the Properties of Sourdough Bread

The application of strains of Lactobacillus paracasei (LP1 and LP2) and Saccharomyces cerevisiae (SC1 and SC2) as starter cultures for sourdough bread making was analyzed. The physicochemical, microbiologial, specific volume, texture, color, microstructural, and sensorial properties of sourdough bread were evaluated. The highest specific volume obtained was for breads made with SC1. Breads made with LP2 or with a combination treatment (LP2/SC1 and LP2/SC2) had improved crumb softness relative to samples with LP1 or with a combination treatment (LP1/SC1 and LP1/SC2). The best scores for sensory analysis were found in breads containing LP2/SC1 in formulation.     

Synthesis of the cancer preventive peptide lunasin by lactic acid bacteria during sourdough fermentation

This study aimed to exploit the potential of sourdough lactic acid bacteria to release lunasin during fermentation of cereal and nonconventional flours. The peptidase activities of a large number of sourdough lactic acid bacteria were screened using synthetic substrates. Selected lactic acid bacteria were used as sourdough starters to ferment wholemeal wheat, soybean, barley, amaranth, and rye flours. Proteinase activity during fermentation was characterized by SDS-PAGE analysis of the water-soluble extracts. Albumins having molecular masses of 18 to 22 kDa, which included the size of lunasin precursors, were markedly affected by proteolysis of lactic acid bacteria. After fermentation, lunasin from the water-soluble extracts was quantified, purified, and identified through RP-HPLC and nano-LC-ESI-MS analyses. Compared to control doughs, the concentration of lunasin increased up to 2-4 times during fermentation. Lactobacillus curvatus SAL33 and Lactobacillus brevis AM7 synthesized the highest concentrations of lunasin in all the flours. Besides the presence of the entire lunasin sequence, fragments containing the immunoreactive epitope RGDDDDDDDDD were also found. This study shows that fermentation by lactic acid bacteria increased the concentration of lunasin to levels that would suggest new possibilities for the biological synthesis and for the formulation of functional foods.     

Bread making with sourdough and intact cereal and legume grains – effect on glycaemic index and glycaemic load

Abstract

The concept of glycaemic index (GI) has led to efforts to develop low-GI foods. Bread contributes around one-quarter of carbohydrate intake in the Swedish diet. In this study, we sought to develop low-GI bread prototypes and examined the effects of bread making on content of total dietary fibre (TDF) and resistant starch (RS). Five bread prototypes were made in a commercial bakery, using sourdough fermentation and intact cereal and legume kernels. Predicted (p-GI) and in vivo GI values were determined, and TDF and RS were quantified. The p-GI value of the five prototypes was between 56 and 68. The confirmed in vivo GI value was 65 and 67 for two of the breads. The TDF content (≥17%) was not affected by bread making, but RS content was increased by three-fold. All breads were categorised as medium-GI, but with low glycaemic load (GL).     

Effect of lactic acid fermentation of lupine wholemeal on acrylamide content and quality characteristics of wheat-lupine bread

Abstract

The effect of supplementing wheat flour at a level of 15% with lupine (Lupinus angustifolius L.) wholemeal fermented by different lactic acid bacteria on acrylamide content in bread crumb as well as on bread texture and sensory characteristics was analysed. The use of fermented lupine resulted in a lower specific volume and crumb porosity of bread on an average by 14.1% and 10.5%, respectively, while untreated lupine lowered the latter parameters at a higher level (30.8% and 20.7%, respectively). The addition of lupine resulted in a higher by 43.3% acrylamide content compared to wheat bread (19.4?µg/kg dry weight (d.w.)). Results showed that acrylamide was significantly reduced using proteolytic Lactobacillus sakei and Pediococcus pentosaceus 10 strains for lupine fermentation. Although the bread supplemented with lupine spontaneous sourdough had the lowest level of acrylamide (15.6?µg/kg?d.w.), it had the malodorous flavour and was unacceptable to the consumers. The lactofermentation could increase the potential use of lupine as a food ingredient while reducing acrylamide formation and enriching bread with high quality proteins.     

Barley bread containing lactic acid improves glucose tolerance at a subsequent meal in healthy men and women

In the present study, we evaluated whether a low glycemic index (GI) breakfast with lactic acid bread had an effect on glucose tolerance and insulinemia at a subsequent high GI lunch meal. A barley bread containing lactic acid and a reference barley bread were consumed in the morning after an overnight fast in random order by 10 healthy men and women. Four hours after the breakfasts, the subjects ate a standardized high GI lunch, and the blood glucose and insulin responses were measured for the next 3 h. Significant lowerings of the incremental glycemic area (-23%, P = 0.033) and of the glucose response at 95 min were found after the lunch meal when the barley bread with lactic acid was given as a breakfast. At 45 min after the lunch meal, the insulin level was significantly lower (-21%, P = 0.045) after the lactic acid bread breakfast, compared with the barley bread breakfast without lactic acid. We concluded that barley bread containing lactic acid eaten at breakfast has the potential to improve second-meal glucose tolerance at a high GI lunch meal 4 h later.     

Lactobacillus plantarum ITM21B fermentation product and chickpea flour enhance the nutritional profile of salt reduced bakery products

The study aimed at improving the nutritional profile of yeast leavened salt reduced sliced bread and puccia type bread fortified with a wheat-based Lactobacillus plantarum ITM21B fermentation product (Bio21B). The protein content of bread made under laboratory conditions was increased by using: (i) chickpea flour (CF) (15% wt/wt flour) and Bio21B or (ii) the Bio21B containing a fungal protease to favour the gluten hydrolysis. Products showed increased protein and total amino acid content and improved protein digestibility. Moreover, the formula significantly affected the protein pattern of breads which, according to the results of the microfluidic two-dimensional electrophoresis (μ2DE) protein pattern, were discriminated as observed by the PCA plot. The use of CF was validated at industrial pilot plant producing salt reduced sliced bread and puccia type bread. The resulting products showed improved nutritional profile and a sensory quality comparable to the company’s products containing salt.     

The sourdough fermentation may enhance the recovery from intestinal inflammation of coeliac patients at the early stage of the gluten-free diet

Purpose

This study aimed at investigating the effect of corn, rice and amaranth gluten-free (GF) sourdoughs on the release of nitric oxide (NO) and synthesis of pro-inflammatory cytokines by duodenal mucosa biopsies of eight coeliac disease (CD) patients.

Methods

Selected lactic acid bacteria were used as starters for the manufacture of corn, rice or amaranth sourdoughs. Chemically acidified doughs, without bacterial starters, and doughs started with baker’s yeast alone were also manufactured from the same GF matrices. Pepsin-trypsin (PT) digests were produced from all sourdoughs and doughs, and used to assay the rate of recovery of biopsy specimens from eight CD patients at diagnosis. The release of NO and the synthesis of pro-inflammatory cytokines interferon-γ (IFN-γ) were assayed.

Results

During fermentation, lactic acid bacteria acidified and grew well (ca. log 9.0?CFU/g) on all GF matrices, showing intense proteolysis. Duodenal biopsy specimens still released NO and IFN-γ when subjected to treatments with basal medium (control), PT-digest from chemically acidified doughs and PT-digest from doughs fermented with baker’s yeast alone. On the contrary, the treatment of all the biopsy specimens with PT-digests from all GF matrices subjected to sourdough fermentation significantly decreased the release of NO and the synthesis of IFN-γ.

Conclusions

During manufacture of GF baked goods, the use of sourdough fermentation could be considered as an adjuvant to enhance the recovery from intestinal inflammation of coeliac patients at the early stage of the gluten-free diet.     

Glycaemic index of four commercially available breads in Malaysia

This study was carried out to determine the blood glucose response and glycaemic index (GI) values of four types of commercially available breads in Malaysia. Twelve healthy volunteers (six men, six women; body mass index, 21.9±1.6 kg/m²; age, 22.9±1.7 years) participated in this study. The breads tested were multi-grains bread (M-Grains), wholemeal bread (WM), wholemeal bread with oatmeal (WM-Oat) and white bread (WB). The subjects were studied on seven different occasions (four tests for the tested breads and three repeated tests of the reference food) after an overnight fast. Capillary blood samples were taken immediately before (0 min) and 15, 30, 45, 60, 90 and 120 min after consumption of the test foods. The blood glucose response was obtained by calculating the incremental area under the curve. The GI values were determined according to the standardized methodology. Our results showed that the M-Grains and WM-Oat could be categorized as intermediate GI while the WM and WB breads were high GI foods, respectively. The GI of M-Grains (56±6.2) and WM-Oat (67±6.9) were significantly lower than the reference food (glucose; GI = 100) (P < 0.05). No significant difference in GI value was seen between the reference food and the GI of WM (85±5.9) and WB (82±6.5) (P > 0.05). Among the tested breads, the GI values of M-Grains and WM-Oat were significantly lower (P < 0.05) than those of WM and WB. There was no relationship between the dietary fibre content of the bread with the incremental area under the curve (r = 0.15, P = 0.15) or their GI values (r = 0.17, P = 0.12), indicating that the GI value of the test breads were unaffected by the fibre content of the breads. The result of this study will provide useful nutritional information for dieticians and the public alike who may prefer low-GI over high-GI foods.     

Sourdough Fermentation of Wheat Flour does not Prevent the Interaction of Transglutaminase 2 with α2-Gliadin or Gluten

The enzyme transglutaminase 2 (TG2) plays a crucial role in the initiation of celiac disease by catalyzing the deamidation of gluten peptides. In susceptible individuals, the deamidated peptides initiate an immune response leading to celiac disease. Several studies have addressed lactic fermentation plus addition of enzymes as a means to degrade gluten in order to prevent adverse response in celiacs. Processing for complete gluten degradation is often harsh and is not likely to yield products that are of comparable characteristics as their gluten-containing counterparts. We are concerned that incomplete degradation of gluten may have adverse effects because it leads to more available TG2-binding sites on gluten peptides. Therefore, we have investigated how lactic acid fermentation affects the potential binding of TG2 to gluten protein in wheat flour by means of estimating TG2-mediated transamidation in addition to measuring the available TG2-binding motif QLP, in α₂-gliadin. We show that lactic fermentation of wheat flour, as slurry or as part of sourdough bread, did not decrease the TG2-mediated transamidation, in the presence of a primary amine, to an efficient level (73%–102% of unfermented flour). Nor did the lactic fermentation decrease the available TG2 binding motif QLP in α₂-gliadin to a sufficient extent in sourdough bread (73%–122% of unfermented control) to be useful for celiac safe food.     

Acid production and conversion of konjac glucomannan during in vitro colonic fermentation affected by exogenous microorganisms and tea polyphenols

Impacts of exogenous microorganisms and tea polyphenols on acid production and conversion during in vitro colonic fermentation of konjac glucomannan (KGM) were assessed in this study. Colonic fermentation of KGM by the fecal extract of healthy adults resulted in a propionate-rich profile, as acetic, propionic, butyric and lactic acids production were 16.1, 13.0, 3.3 and 20.2?mmol/L, respectively. Inoculation of one of ten exogenous microorganisms in the fermentative systems increased acetic, propionic and butyric acids production by 50?230%, 9?190% and 110?350%, respectively, and also accelerated lactic acid conversion by 14?40%. Tea polyphenols in the fermentative systems showed clear inhibition on both acid production and conversion; however, this inhibition could be partially or mostly antagonised by the inoculated exogenous microorganisms, resulting in improved acid production and conversion. In total, Lactobacillus brevis and Sterptococcus thermophilus were more able to increase acid production, and the propionate-rich profile was not changed in all cases.     

Vinegar supplementation lowers glucose and insulin responses and increases satiety after a bread meal in healthy subjects

OBJECTIVE: To investigate the potential of acetic acid supplementation as a means of lowering the glycaemic index (GI) of a bread meal, and to evaluate the possible dose-response effect on postprandial glycaemia, insulinaemia and satiety. SUBJECTS AND SETTING: In all, 12 healthy volunteers participated and the tests were performed at Applied Nutrition and Food Chemistry, Lund University, Sweden. INTERVENTION: Three levels of vinegar (18, 23 and 28 mmol acetic acid) were served with a portion of white wheat bread containing 50 g available carbohydrates as breakfast in randomized order after an overnight fast. Bread served without vinegar was used as a reference meal. Blood samples were taken during 120 min for analysis of glucose and insulin. Satiety was measured with a subjective rating scale. RESULTS: A significant dose-response relation was seen at 30 min for blood glucose and serum insulin responses; the higher the acetic acid level, the lower the metabolic responses. Furthermore, the rating of satiety was directly related to the acetic acid level. Compared with the reference meal, the highest level of vinegar significantly lowered the blood glucose response at 30 and 45 min, the insulin response at 15 and 30 min as well as increased the satiety score at 30, 90 and 120 min postprandially. The low and intermediate levels of vinegar also lowered the 30 min glucose and the 15 min insulin responses significantly compared with the reference meal. When GI and II (insulinaemic indices) were calculated using the 90 min incremental area, a significant lowering was found for the highest amount of acetic acid, although the corresponding values calculated at 120 min did not differ from the reference meal. CONCLUSION: Supplementation of a meal based on white wheat bread with vinegar reduced postprandial responses of blood glucose and insulin, and increased the subjective rating of satiety. There was an inverse dose-response relation between the level of acetic acid and glucose and insulin responses and a linear dose-response relation between acetic acid and satiety rating. The results indicate an interesting potential of fermented and pickled products containing acetic acid.     

Anti-Photoaging Effect of Rhodiola rosea Fermented by Lactobacillus plantarum on UVA-Damaged Fibroblasts

UVA can cause oxidative stress and photoaging of cells. We established a UVA-induced oxidative stress model of human fibroblasts and focused on the antioxidant and anti-photoaging ability of Lactobacillus plantarum fermented Rhodiola rosea. Compared with the unfermented Rhodiola rosea, Lactobacillus plantarum fermented Rhodiola rosea has better DPPH free radical and hydroxyl free radical scavenging ability, significantly reduces the content of reactive oxygen species (ROS), and improves the antioxidant level. Further studies have shown that the Lactobacillus plantarum fermented Rhodiola rosea can activate the Nrf2/Keap1 signaling pathway and up-regulate heme oxygenase-1 (HO-1), NAD(P)H quinone dehydrogenase 1 (NQO1), catalase (CAT) and glutathione Peptide peroxidase (GSH-Px), and protect fibroblasts from oxidative stress caused by UVA. On the other hand, Lactobacillus plantarum fermented Rhodiola rosea significantly reduces the activity of metalloproteinases in the cell, thereby increasing the collagen and elastin in the cell, alleviating the photoaging caused by UVA. Finally, we concluded that the antioxidant capacity and anti-photoaging ability of Lactobacillus plantarum fermented Rhodiola rosea are better than that of unfermented Rhodiola rosea.     

The Consumption of Synbiotic Bread Containing Lactobacillus sporogenes and Inulin Affects Nitric Oxide and Malondialdehyde in Patients with Type 2 Diabetes Mellitus: Randomized,Double-Blind,Placebo-Controlled Trial

Objectives: To our knowledge, no reports are available indicating the effects of synbiotic bread consumption on nitric oxide (NO), biomarkers of oxidative stress, and liver enzymes among patients with type 2 diabetes mellitus (T2DM). This study was performed to determine the effects of the daily consumption of synbiotic bread on NO, biomarkers of oxidative stress, and liver enzymes in patients with T2DM.

Methods: This randomized, double-blind, placebo-controlled trial was performed among 81 patients with diabetes, aged 35–70 years old. After a 2-week run-in period, patients were randomly divided into 3 groups: group A (n = 27) received synbiotic bread containing viable and the heat-resistant probiotic Lactobacillus sporogenes (1 × 10⁸ CFU) and 0.07 g inulin per 1 g, group B (n = 27) received probiotic bread containing Lactobacillus sporogenes (1 × 10⁸ CFU), and group C (n = 27) received control bread for 8 weeks. Patients were asked to consume the synbiotic, probiotic, or control breads 3 times a day in 40 g packages for a total of 120 g/day. Fasting blood samples were taken at baseline and after an 8-week intervention for quantificationof related markers.

Results: After 8 weeks, the consumption of synbiotic bread compared to the probiotic and control breads resulted in a significant rise in plasma NO (40.6 ± 34.4 vs 18.5 ± 36.2 and ?0.8 ± 24.5 µmol/L, respectively, p < 0.001) and a significant reduction in malondialdehyde (MDA) levels (?0.7 ± 0.7 vs 0.6 ± 1.7 and 0.5 ± 1.5 µmol/L, respectively, p = 0.001). We did not find any significant effect of the synbiotic bread consumption on plasma total antioxidant capacity (TAC), plasma glutathione (GSH), catalase, serum liver enzymes, calcium, iron, magnesium levels, and blood pressure compared to the probiotic and control breads.

Conclusion: In conclusion, consumption of the synbiotic bread for 8 weeks among patients with T2DM had beneficial effects on plasma NO and MDA levels; however, it did not affect plasma TAC, GSH, catalase levels, serum liver enzymes, calcium, iron, magnesium levels, and blood pressure.     

Potential probiotic attributes and antagonistic activity of an indigenous isolate Lactobacillus plantarum DM5 from an ethnic fermented beverage “Marcha” of North Eastern Himalayas

A novel isolate DM5 identified as Lactobacillus plantarum displayed in vitro probiotic properties as well as antimicrobial activity. It showed adequate level of survival to the harsh conditions of the gastrointestinal tract and survived low acidic pH 2.5 for 5?h. Artificial gastric juice and intestinal fluidic environment decreased the initial viable cell population of isolate DM5 only by 7% and 13%, respectively, while lysozyme (200?µg/ml) and bile salt (0.5%) enhanced its growth. It was found to deconjugate taurodeoxycholic acid, indicating its potential to reduce hypercholesterolemia. Isolate DM5 demonstrated cell surface hydrophobicity of 53% and autoaggregation of 54% which are the prerequisite for adhesion to epithelial cells and colonization to host. Bacteriocin activity of isolate was found to be 6400?AU/ml as it inhibited the growth of food borne pathogens Escherichia coli, Staphylococcus aureus, and Alcaligenes faecalis. The bactericidal action of bacteriocin from isolate was analyzed by flow cytometry, rendering its use as prospective probiotic and starter culture in food industry.     

Diet-derived changes by sourdough-fermented rye bread in exhaled breath aspiration ion mobility spectrometry profiles in individuals with mild gastrointestinal symptoms

The potential of utilising exhaled breath volatile organic compound (VOC) profiles in studying diet-derived metabolic changes was examined. After a four-week initial diet period with white wheat bread (WW), seven participants received in randomised order high-fibre diets containing sourdough whole grain rye bread (WGR) or white wheat bread enriched with bioprocessed rye bran (WW?+?BRB), both for 4?weeks. Alveolar exhaled breath samples were analysed with ChemPro^®100i analyser (Environics OY, Mikkeli, Finland) at the end of each diet period in fasting state and after a standardised meal. The AIMS signal intensities in fasting state were different after the WGR diet as compared to other diets. The result suggests that WGR has metabolic effects not completely explained by the rye fibre content of the diet. This study encourages to utilise the exhaled breath VOC profile analysis as an early screening tool in studying physiological functionality of foods.     

The acute impact of ingestion of breads of varying composition on blood glucose, insulin and incretins following first and second meals

Structural characteristics and baking conditions influence the metabolic responses to carbohydrate-containing foods. We hypothesized that consumption of whole wheat or sourdough breads would have a favourable effect on biomarkers of glucose homeostasis after first and second meals, compared with those for white bread. Ten overweight volunteers consumed 50 g available carbohydrate of each of the four breads (white, whole wheat, sourdough, whole wheat barley) followed 3 h later by a standard second meal. Blood was sampled for 3 h following bread ingestion and a further 2 h after the second meal for determination of glucose, insulin, paracetamol (indirect marker of gastric emptying), glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1). Glucose and GLP-1 responses to sourdough bread were lower (P < 0.05) than whole wheat and whole wheat barley breads. Glucose area under the curve (AUC) for sourdough bread was lower than those for whole wheat (P < 0.005) and whole wheat barley (P < 0.03) breads for the entire study. GIP AUC after sourdough bread ingestion was lower compared to white (P < 0.004) and whole wheat barley (P < 0.002) breads following the second meal. There were no significant differences in insulin and paracetamol concentrations among the test breads. Ultra-fine grind whole wheat breads did not result in postprandial responses that were lower than those of white bread, but sourdough bread resulted in lower glucose and GLP-1 responses compared to those of these whole wheat breads following both meals.     

Antimicrobial activity of selected synbiotics targeted for the elderly against pathogenic Escherichia coli strains

The aim of the present study was to evaluate the antimicrobial activity of two synbiotic combinations, Lactobacillus fermentum with short-chain fructooligosaccharides (FOS-LF) and Bifidobacterium longum with isomaltooligosaccharides (IMO-BL), against enterohaemorrhagic Escherichia coli O157:H7 and enteropathogenic E. coli O86. Antimicrobial activity was determined (1) by co-culturing the synbiotics and pathogens in batch cultures, and (2) with the three-stage continuous culture system (gut model), inoculated with faecal slurry from an elderly donor. In the co-culture experiments, IMO-BL was significantly inhibitory to both E. coli strains, while FOS-LF was slightly inhibitory or not inhibitory. Factors other than acid production appeared to play a role in the inhibition. In the gut models, both synbiotics effectively inhibited E. coli O157 in the first vessel, but not in vessels 2 and 3. E. coli O86 was not significantly inhibited.     

Glycemic index of selected carbohydrate-based foods consumed in Qatar

This study determined the glycemic index (GI) of selected carbohydrate-rich foods consumed in Qatar. Recruited volunteers (n = 19) consumed two reference foods, glucose and white bread, and 10 test foods. The foods tested for their GI were Fatayer (cheese, Zaatar, spinach), Tanour white bread, white basmati rice, Shearia, Muhalabea, Sago Awama and Qurs Aquili. Results of the study indicated that all of the foods tested had high GIs (>?70). Shearia had the highest GI (84.0 ± 1.85) using the glucose scale, and Fatayer Spinach had the lowest GI (77.6 ± 2.00). There was no significant correlation between the GI of all test foods, using glucose or white bread as standard foods, and the age or the body mass index of the volunteers (P >?0.05). The study provides data on the GIs of carbohydrate-based foods consumed in Qatar and other Arabian Gulf countries that have not been reported before.     

Nutritional quality of fermented defatted soya and flaxseed flours and their effect on texture and sensory characteristics of wheat sourdough bread

The use of soya and flaxseed flours fermented with Pediococcus acidilactici for wheat sourdough bread production was investigated. The protein digestibility, biogenic amine contents of soya and flaxseed sourdoughs, texture and sensory features of bread were studied. The fermentation with P. acidilactici significantly improved soya and flaxseed protein extraction and increased protein digestibility on an average by 13.5%. The concentrations of histamine (3.8 ± 2.3 and 4.0 ± 0.2 mg/kg), tyramine (4.6 ± 0.7 and 19.3 ± 1.8 mg/kg) and putrescine (66.4 ± 1.3 and 11.3 ± 3.0 mg/kg) do not present a health risk for consumers due to their relatively low levels in fermented plant products. The flaxseed sourdoughs influenced a 17.5% higher specific volume and a 4.6% lower crumb hardness of bread than those of soya sourdoughs, and did not disimprove sensory properties of bread. However, the fermented soya additives decreased acceptability of bread because of intensive taste and odour.