Isolation of lactic acid bacteria starters from <Emphasis Type="Italic">Jeung</Emphasis>-<Emphasis Type="Italic">pyun</Emphasis> for sourdough fermentation

Lactic acid bacteria (LAB) are key for the fermentation of sourdoughs to improve the quality and nutritive value of bread. The aim of this study was to isolate the LAB starter for sourdough fermentation from Jeung-pyun, a Korean traditional rice cake. Among the twenty two LAB screened, five isolates were selected based on exo-polysaccharide production. Among them, three isolates showed cell growth greater than 8.5 Log CFU/g, maximum increase in the volume of dough, and dextran concentration up to 0.16%. During the sourdough fermentation, pH and total titratable acidity (TTA) were changed, as the three isolates synthesized lactic acid and acetic acid with fermentation quotients less than 2.0. They were identified as Leuconostoc lactis EFEL005, Lactobacillus brevis EFEL004, and Le. citreum EFEL006. They displayed good fermentation properties (growth, dextran production, pH, and TTA) in dough and they are regarded as potential starters to be used in sourdough fermentation.     

Fermented<Emphasis Type="Italic"> Phaseolus vulgaris</Emphasis>: acceptability and intestinal effects

Dry beans such as Phaseolus vulgaris are an important source of nutrients, especially in developing countries. However, their consumption is limited by the flatulence problem, which occurs in the gut after their ingestion, owing to the presence of highly fermentable compounds, such as -galactosides, soluble dietary fibre, and resistant starch. It has been shown that natural fermentation reduces the content of these compounds by about 90%. In the present work, the effects of the consumption of unfermented and fermented beans (P. vulgaris) on the bowel habits (frequency and faecal volume) and on the main adverse intestinal symptoms usually associated with bean consumption were compared. This study was carried out for 28 days with ten women, whose age ranged between 25 and 40 years, eating 45 g of fermented-cooked and cooked beans for 7 days, with a 2-week break between the experimental periods. A sensorial evaluation with 51 panellists was performed revealing that 56% of the panel gave the fermented samples a score between 6 and 9, corresponding to slightly like it and really like it, respectively. The consumption of fermented beans significantly decreased the flatulence problem by 56.1%, the intestinal noises by 48% and the nausea by 80%. Abdominal bloating was reduced by 11%. It was concluded that the fermented and cooked beans were palatable and that the process could decrease the flatulence problem that is usually caused by the consumption of P. vulgaris by humans.     

Production of biogenic amines by<Emphasis Type="Italic"> Morganella morganii</Emphasis>,<Emphasis Type="Italic"> Klebsiella pneumoniae</Emphasis> and<Emphasis Type="Italic"> Hafnia alvei</Emphasis> using a rapid HPLC method

The histidine decarboxylating activity and production of biogenic amines by Morganella morganii (NCIMB, 10466), Klebsiella pneumoniae (NCIMB, 673) and Hafnia alvei (NCIMB, 11999) were investigated using a rapid HPLC method. Derivatisation of the bacterial samples was carried out using benzoyl chloride. A gradient elution system was used for analysis with a mixture of acetonitrile and HPLC grade water. Bacterial strains not only produce histamine in histidine-enriched broth but also the other biogenic amines. The chromatographic results show that bacterial strains are also capable of producing spermine and spermidine in histidine-enriched broth. Bacterial ammonia production by all three strains was clearly detected since ammonia is generated during the degradation of histidine. The study demonstrates that the highest histamine production was obtained by Morganella morganii, followed by Klebsiella pneumoniae, and the lowest with the Hafnia alvei. Therefore, Morganella morganii and Klebsiella pneumoniae have strong histidine decarboxylase activity since they are prolific histamine-forming bacteria     

Influence of starter culture combinations of<Emphasis Type="Italic"> Lactobacillus fermentum</Emphasis>,<Emphasis Type="Italic"> Saccharomyces cerevisiae</Emphasis> and<Emphasis Type="Italic"> Candida krusei</Emphasis> on aroma in Ghanaian maize dough fermentation

Various combinations of Lactobacillus fermentum, Saccharomyces cerevisiae and Candida krusei were investigated as starter cultures for the fermentation of the Ghanaian maize dough. The four combinations used were each yeast species with L. fermentum, both yeast species together, and both yeast species together with L. fermentum. Maize dough fermented spontaneously was also used as control. The aroma profile, acidity values and sensory characteristics of all dough samples were compared. Using Principal Component Analysis (PCA), the aroma profiles of the dough samples could be separated into five distinct groups based on the type of fermentation. Fermentations where S. cerevisiae and C. krusei were combined produced the highest concentrations of aroma compounds, particularly esters, but were judged as having the lowest acceptability scores. A more balanced profile that included alcohols, carbonyls, esters and acids was obtained with the combination of L. fermentum and C. krusei, which produced fermented dough with a high sensory score comparable to spontaneous fermentations. Combinations of L. fermentum and S. cerevisiae produced high concentrations of ethanol and fusel alcohols. Lactic and acetic acid concentrations were highest with the combined use of all three starter cultures.     

Development of a nucleic acid lateral flow immunoassay for simultaneous detection of <Emphasis Type="Italic">Listeria</Emphasis> spp. and <Emphasis Type="Italic">Listeria</Emphasis><Emphasis Type="Italic">monocytogenes</Emphasis> in food

We present a new nucleic acid lateral flow immunoassay (NALFIA) for the assessment of listeria contamination. The detection procedure starts with enrichment of sample in Half Fraser broth (24 h). Following isolation of DNA, a duplex PCR is performed with two labelled primer sets, one generic and directed to a specific sequence of the gene encoding 16S rRNA from Listeria spp. and the other specific and directed to a part of the prfA gene encoding the central virulence gene regulator from the food pathogen Listeria monocytogenes (3.5 h). The PCR solution is directly added to the one-step assay device and the appearance of a grey/black line is indicative of the presence of specific amplicons (max 15 min). In all tests performed, the method correctly identified L. monocytogenes and strains of Listeria spp. PCR material of over 20 food samples was tested by NALFIA. The method proved to be useful for the detection of L. monocytogenes in different kinds of food samples.     

Characterisation of the key aroma compounds in the peel oil of Pontianak oranges (<Emphasis Type="Italic">Citrus nobilis</Emphasis> Lour. var. <Emphasis Type="Italic">microcarpa</Emphasis> Hassk.) by aroma reconstitution experiments

Nineteen odour-active compounds previously identified with high Flavour Dilution factors in an extract from the peel oil of Pontianak oranges (Citrus nobilis Lour. var. microcarpa Hassk.) were quantified using stable isotope dilution assays (SIDA). For this purpose, four new SIDA were developed, i.e. for the quantification of (E)-2-dodecenal, geraniol, nerol, and 1-phenylethanethiol. The results showed that (R)-limonene, myrcene, and (R)-α-pinene were the predominant compounds present in concentrations between 0.4 and 60 mg/g peel. An aroma recombinate containing the nineteen aroma compounds in the concentrations naturally occurring in the peel oil elicited the overall aroma of the peel oil itself, thus confirming the identification experiments. Furthermore, omission experiments showed that the unique odour quality of the peel is significantly influenced by the resinous, sulphurous-smelling 1-phenylethanethiol, although its concentration was only 38 ng/g peel.     

Prevalence,genetic diversity,and antibiotic susceptibility of <Emphasis Type="Italic">Cronobacter</Emphasis> spp. (<Emphasis Type="Italic">Enterobacter sakazakii</Emphasis>) isolated from <Emphasis Type="Italic">Sunshik</Emphasis>, its ingredients and soils

The prevalence, genetic diversity, and antibiotic susceptibility of Cronobacter species (Enterobacter sakazakii) isolated from sunshik products, its ingredients, and root vegetable farm’s soils were investigated to analyze main reservoirs and contaminated sources of Cronobacter spp. Cronobacter spp. was isolated from 9 of 15 sunshik products, 26 of 72 its ingredients, and 2 of 39 soils. The root vegetables such as sweet potato and carrot showed higher contamination rate (70%) than the other sunshik ingredients. All isolates showed 929 bp band amplified from 16S rRNA and resistant to ampicillin, amoxicillin/clavulanic acid, and cefazolin. All isolates showed diverse random-amplified polymorphic DNA (RAPD) and pulsed-field gel electrophoresis (PFGE) band patterns. However, 3 cases of RAPD banding patterns between clinical strains and isolates from sunshik products and root vegetables (yam, carrot) were related with similarities level of 80%. These studies indicated that root vegetables can be an important contamination source of Cronobacter spp. in sunshik products. Thus, the preparation of root vegetables for manufacturing sunshik products used as a weaning diet was handled with more care than the other sunshik ingredients.     

Influence of fermentation on the nutritional value of two varieties of<Emphasis Type="Italic"> Vigna sinensis</Emphasis>

Cowpeas ( Vigna sinensis) are a good source of protein and energy. They are widely consumed all over the world, mainly in rural populations, and satisfy a considerable proportion of the protein requirements. However, like other pulses, cowpeas contain several antinutritional factors, which limit their consumption and affect the digestibility and bioavailability of nutrients. Fermentation seems to enhance the nutritive value of legumes. The present work studies the effect of natural fermentation and subsequent cooking process of two varieties of Vigna sinensis on the content of protein, minerals, ash, fat, soluble and insoluble dietary fibre, -galactosides, inositol phosphates, trypsin inhibitor activity (TIA), water-soluble vitamins (thiamin and riboflavin) and protein quality parameters, in vivo digestibility and PER (protein efficiency ratio). The processes applied caused a significant increase of vitamin B_2, and significant reductions in the contents of TIA (40%) and phytates (100%), main antinutritional factors present in cowpeas. Likewise, the soluble fibre and -galactosides compounds that produce flatulence diminished (67 and 100%, respectively). Protein digestibility for Orituco variety was adequate among legumes (82.8–88.4%), although only Vigna sinensis var. Orituco showed an acceptable PER value (1.63).     

Estrogenic effects of various extracts from <Emphasis Type="Italic">Chamdanggui</Emphasis> (<Emphasis Type="Italic">Angelica gigas</Emphasis> Nakai) and <Emphasis Type="Italic">sogdan</Emphasis> (<Emphasis Type="Italic">Phlomis umbrosa</Emphasis> Turcz)

The various extracts from chamdanggui (Angelica gigas Nakai) and sogdan (Phlomis umbrosa Turcz) were evaluated for estrogenic activity and characterized according to HPLC profile. Chamdanggui and sogdan were individually extracted with 4 solvents (hot water, 70% ethanol, n-butanol, and dichloromethane) of differing polarities. Estrogenic activity was determined by E-screen using an estrogen-dependent MCF-7 BUS cell. Although almost all extracts showed estrogenic effects in a concentrationdependent manner, the hot water extract from chamdanggui (250 μg/mL) had the higher effect (138%). Among 90 fractions using HPLC separation of the hot water extract from chamdanggui, fraction 21 and 28 produced the highest estrogenic effects of 178 and 163% at 10 μg/mL, respectively. The results imply that the hot water extract from chamdanggui could be useful as an alternative hormone replacement therapy.     

Optimization of a process for enzyme-assisted pigment extraction from grape (<Emphasis Type="Italic">Vitis vinifera</Emphasis> L.) pomace

A process for enzyme-assisted extraction of polyphenols from grape pomace was developed on laboratory and pilot-plant scale. After resuspending grape pomace in water, the skins were ground and the resulting mash was pasteurized to inactivate the deteriorative enzymes responsible for polyphenol degradation, and then pre-extracted with hot water. Subsequently, cell wall polysaccharides were hydrolyzed. The extract was separated from the solid residue by pressing, and finally spray dried. Before scaling-up, enzymatic hydrolysis was optimized on laboratory scale using a D-optimal design and analyzed by response surface methodology. A mixture of pectinolytic and cellulolytic enzyme preparations (ratio 2:1) yielded the highest amounts of phenolic compounds after 2 h of treatment, applying a dosage of 4,500 mg/kg (based on dry matter) at T = 40 °C and pH 4.0. Aqueous pre-extraction of the pomace followed by enzymatic treatment resulted in significantly improved extraction yields reaching 91.9, 92.4, and 63.6% for phenolic acids, non-anthocyanin flavonoids and anthocyanins, respectively. As the yields obtained were comparable to those from sulfite-assisted extraction, this process can be considered a suitable alternative to the application of sulfite.     

Effect of lactic acid fermentation on antioxidant properties and phenolic acid contents of oyster (<Emphasis Type="Italic">Pleurotus ostreatus</Emphasis>) and chanterelle (<Emphasis Type="Italic">Cantharellus cibarius</Emphasis>) mushrooms

Fruiting bodies of Pleurotus ostreatus (oyster) and Cantharellus cibarius (chanterelle) mushrooms underwent acid fermentation using 3 strains of lactic acid bacteria (LAB) as starter cultures. Polyphenol contents, antioxidant activities, and phenolic acid contents in fresh, blanched, and fermented mushrooms were investigated. Fruiting bodies of oyster mushrooms exhibited higher total phenolic contents than chanterelle mushrooms. Blanching caused a decrease in polyphenol contents and antioxidant activities in both mushroom types. No important differences were observed in total phenolic compound contents (measured using Folin-Ciocalteau reagent) in mushrooms using different LAB strains. Lactobacillus plantarum was the most useful microorganism for lactic acid fermentation of fruiting bodies for reduction of the pH value. The highest concentrations of single phenolic acids: gallic, homogentisic, and ferulic acids were present in mushrooms fermented using L. plantarum.     

Novel anticoagulant compound from fermented red alga <Emphasis Type="Italic">Pachymeniopsis elliptica</Emphasis>

Natural fermentation was tested as a method of releasing active compounds during screening for potential anticoagulant activity in three types of algae (Pachymeniopsis elliptica, Sargassum horneri, and Ulva pertusa). Freeze dried algae samples (2.5 g) were fermented by adding 75 g of sugar and 500 mL of water and thereafter kept at room temperature (25 °C) for 3 months. Activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT) were measured every 2 weeks for 3 months to determine the optimum time for the highest activity. Fermented P. elliptica, (which had the highest activity) was subjected to anion exchange chromatography (DEAE-cellulose) and sepharose 4B gel permeation chromatography. The purified sample was analyzed by agarose-gel electrophoresis and polyacrylamide gel electrophoresis (PAGE) to confirm the purification and to determine the molecular mass, respectively. The 360 μg/mL of purified compound (Mwt > 500,000 Da) had both APTT and PT activities (>1,000 s). However, at the concentrations of 180 μg/mL, purified compound and heparin showed 540 and >1,000 s APTT activity, respectively. Though, the purified compound of P. elliptica considered as a weaker anticoagulant than heparin, this purified anticoagulant polysaccharide could be considered as a good alternative source as an anticoagulant. Moreover, the technique of fermentation is an inexpensive and feasible, this purified anticoagulant polysaccharide compound could be used in pharmaceutical and biomedical industry. Further investigations need to be performed to determine the mechanism of this novel anticoagulant compound. The authors Prashani Mudika Ekanayake and Chamilani Nikapitiya contributed equally to this work.     

Investigations of the natural microflora of poppy seeds (<Emphasis Type="Italic">Papaver somniferum</Emphasis>) and hazelnut kernels (<Emphasis Type="Italic">Corylus avellana</Emphasis>) including microbiological decomposition

Fatty seeds of Papaver somniferum and Corylus avellana undergo a rapid microbial degradation after being ground. Those bacteria and fungi which are mainly responsible for the microbial decay were identified, and the most important growth and death processes were documented using crucial indicator-organisms. Additionally, an aflatoxin-screening was carried out in order to assess the possible risk-potential of food intoxication. The acid value (indicator for free fatty acids) of poppy seeds and hazelnut kernels was determined during their fermentation in order to document the decomposition of triglycerides.In this study it could be proved that initially a natural decay of oil seeds is caused by bacteria, yeasts and mould fungi. After the bacteria died in the course of time, yeasts and mould fungi dominated the germ spectrum. Bacteria taking part in the degradation were identified as varieties of Staphylococcus xylosus, Enterobacteriaceae and coliforms. Yeasts were identified as Pichia burtonii, and the mould fungi are associated with the genus Alternaria.On account of the absence of the genus Aspergillus in the spectrum of mould fungi, no aflatoxin was produced.     

Ethanolic fermentation from red ginseng extract using <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> and <Emphasis Type="Italic">Saccharomyces carlsbergensis</Emphasis>

The pH of red ginseng extracts fermented with Saccharomyces cerevisiae and Saccharomyces carlsbergensis decreased rapidly during 3 days of fermentation, with no further significant change thereafter. After 20 days of fermentation, a relatively small difference remained in the acidity of extracts fermented with S. cerevisiae (0.54%) and S. carlsbergensis (0.58%). Reducing sugar in the S. cerevisiae and S. carlsbergensis extracts decreased from 258.6 to 45.4 and 43.2 mg/mL glucose equivalents, respectively; and ethanol contents increased from 1.5% at day 0 to 16.0 and 15.0%, respectively, at day 20. Ginsenosides Rb₁, Rb₂, Rc, Re, Rf, and Rg₁ decreased during the fermentation with S. cerevisiae, but Rd and Rg₃ increased by day 12. Ginsenosides Rb₁, Rb₂, Rc, Re, and Rg₁ decreased gradually in the extract with S. carlsbergensis, but Rd and Rg₃ were increased at day 6 and 9, respectively.     

Xanthan gum production under different operational conditions by <Emphasis Type="Italic">Xanthomonas axonopodis</Emphasis> pv <Emphasis Type="Italic">vesicatoria</Emphasis> isolated from pepper plant

The influence of operational conditions (pH, stirrer speed, and temperature) used in the process of xanthan production by Xanthomonas axonopodis pv vesicatoria (XCVA3-1) isolated from pepper plant were evaluated through yield of xanthan and compared with control strain Xanthomonas campestris NRRL-B 1459. Different conditions used during the fermentation affected the xanthan production. In this study the best combination of yield was obtained, reaching 1.325 g/100 mL with the use of pH 7.0, 30°C, and 250 rpm during fermentation. Increased yield of xanthan production can be obtained at high agitation values, with the maximum at 400 rpm. Higher yields of gum production can be obtained at 30°C and the optimum pH was found 7.0. This results were similar for the X. campestris NRRL-B 1459.     

Studies concerning the use of <Emphasis Type="Italic">Lactobacillus helveticus</Emphasis> and <Emphasis Type="Italic">Kluyveromyces marxianus</Emphasis> for rye sourdough fermentation

The aim of this study was to investigate the fermentation behaviour, antioxidant activity and rheological behaviour of the sourdoughs prepared with Lactobacillus helveticus and Kluyveromyces marxianus. The final acidity of the sourdough after 18 h of fermentation was higher at higher temperatures (40 °C) and for the formulations with whole rye flour. The highest lactic/acetic acid ratios were obtained in case of more fluid sourdoughs fermented at 40 °C. The antioxidant properties of the sourdoughs are correlated with metabolic activity of the microorganisms, the DPPH radical scavenging activity being higher for optimum conditions of Lactobacillus helveticus growth. On the other hand, the rheological properties of the sourdoughs are not significantly influenced by the temperature. Sourdoughs formulations with whole flour are more viscous, as well as the controls fermented by the spontaneous microflora. The results of the bread-making process simulation by means of Mixolab indicate differences between dough formulations mainly depending on flour type.     

Quantitative determination of <Emphasis Type="Italic">Lactobacillus</Emphasis> spp. in milk using a series piezoelectric quartz crystal sensor

A series piezoelectric quartz crystal (SPQC) sensor was developed for quantitative determination of Lactobacillus spp. populations in milk. When the electrodes were immersed in a reaction cell with bacterial inoculum, the change of frequency was caused by the impedance change of the microbial metabolism. A significant frequency decrease was found due to the coagulation of milk when the Lactobacillus spp. was cultivated in the media. The SPQC sensor system established in this study demonstrated the specificity and selectivity for detection of Lactobacillus spp. in milk sample. The calibration curve of detection time against density of Lactobacillus spp. shows a linear correlation coefficient (R ² = 0.8453) over the range of 10²–2.4 × 10⁵ CFU ml⁻¹. The detection time was influenced by the addition of peptone and glucose. The sensor exhibited rapid (within 4 h) and enabled real time monitoring of Lactobacillus spp. growth. This system is potentially applicable to detect Lactobacillus spp. concentration at local farm when a suitable temperature control device is adapted.     

Optimization of Fermentation Parameters for Higher Lovastatin Production in Red Mold Rice through Co-culture of <Emphasis Type="Italic">Monascus purpureus</Emphasis> and <Emphasis Type="Italic">Monascus ruber</Emphasis>

Monascus, fermented rice (red mold rice), has been found to reduce the serum total cholesterol and triglyceride due to presence of lovastatin. Lovastatin acts as an inhibitor of 3-hydroxy-3-methyl glutaryl coenzyme A reductase. Coculture of Monascus purpureus MTCC 369 and Monascus ruber MTCC 1880 was used to produce red mold rice by solid-state fermentation. Optimization of different fermentation process parameters such as temperature, fermentation time, inoculum volume, and pH of the solid medium was carried out by Box–Behnken’s factorial design of response surface methodology to maximize lovastatin concentration in red mold rice. Maximum lovastatin production of 2.83 mg/g was predicted at 14th day in solid medium under optimized process condition.