Kinema — a traditional soybean fermented food: proximate composition and microflora

Kinema, a soybean fermented alkaline food, is a meat substitute to a majority of the people of the eastern Himalayan regions. The moisture content of kinema was 62%; on dry weight basis, kinema contained about 48% protein, 17% fat, 28% carbohydrate and 7% ash; the energy value was 2·0 MJ/100 g. The corresponding values in raw soybeans were 11%, 47%, 22%, 26%, 5% and 2·1 MJ/100 g. While the pH of raw soybeans was neutral to slightly acidic (average 6·75), that of kinema was distinctly alkaline (average 7·89). Free fatty acidity in kinema was about 33 times higher than raw soybeans. A total of 502 bacterial strains representing Bacillus subtilis and Enterococcus faecium, and 198 yeast strains representing Candida parapsilosis and Geotrichum candidum were isolated from 50 samples of kinema. Bacillus subtilis was the only micro-organism recovered in raw soybeans. In kinema, B. subtilis most dominant (3-5 × 10⁸ cfu g^-1 wet weight) followed by E. faecium (5-9 × 10⁷ cfu g^-1) occurring in all market and laboratory-made samples. The populations of C. parapsilosis occurring in 50-80% samples was 0·3-9 × 10 cfu g^-1, and that of G. candidum occurring in 40-50% of market samples was 0·8-4 · 10 cfu g^-1.     

Strictly anaerobic halophiles isolated from canned Swedish fermented herrings (Surströmming)

Strictly anaerobic halophiles were isolated from canned Swedish fermented herrings (Surstr?mming). All isolates were phenotypically uniform with some exceptions and were identified as the genus Haloanaerobium and assigned to either Haloanaerobium praevalens or Haloanaerobiuim alcaliphilum. A comparative analysis of 16S rDNA sequences revealed that the representative strain S-8 of the isolates was identical to that of Haloanaerobium praevalens DSM 2228T. Furthermore, this strain exhibited high levels (> 80%) of DNA-DNA homology with Haloanaerobium praevalens DSM 2228T. This is a novel report of halophilic anaerobes isolated from a food product. Such anaerobes may contribute to the intense flavor and the swollen can characteristics of Swedish fermented herring.     

Probiotic lactic acid bacteria isolated from traditional Korean fermented foods based on β-glucosidase activity

This study was designed to isolate lactic acid bacteria (LAB) with β-glucosidase activity and probiotic properties from Korean fermented foods. Among nine isolates, four LAB strains had excellent survival rates at pH 2.5 with 0.3% (w/v) pepsin for 3 h and 0.3% (w/v) oxgall for 24 h. Four LAB strains did not produce β-glucuronidase and showed adhesion ability to HT-29 cells that was superior to that shown by the reference strain Lactobacillus rhamnosus GG. All four strains were sensitive to ampicillin, tetracycline, chloramphenicol, and doxycycline. These strains were identified as Leuconostoc mesenteroides H40, Lactobacillus plantarum FI10604, L. brevis FI10700, and L. perolens FI10842 by 16S rRNA gene sequence, respectively. It was found that L. perolens FI10842 produced the highest β-glucosidase activity (49.10 mU/mL). These results indicate that the four LAB strains could be used as potential probiotic. Especially L. perolens FI10842 could be used as a starter culture for fermentation.     

Effect of probiotic co-cultures on physico-chemical and biochemical properties of small ruminants’ fermented milk

Small ruminants' fermented probiotic milk is an alternative to fermented cows' milk, especially because of the monounsaturated/polyunsaturated fatty acid profiles. The technological and biochemical potential of Bifidobacterium and Lactobacillus co-cultures, with or without inulin, on goats' and ewes' milk was assessed. Microbial stability, lactose consumption, organic acid production, proteolytic parameters and conjugated linoleic acid (CLA) production in situ, were followed in ewes' and goats’ fermented milk (EFM and GFM, respectively) over 21 days at 4 °C; technological feasibility for probiotic fermented milk production was shown. In EFM, all co-cultures presented high viable cell numbers (>7.0 log cfu mL⁻¹) throughout storage, presenting faster acidification capacities and higher CLA isomer levels than in GFM. Inulin had no impact on probiotic growth, yet contributed to storage stability. CLA isomers and proteolysis indices were co-culture dependent traits: for example, co-culture of Bifidobacterium animalis B94 with Lactobacillus acidophilus L10 registered the best CLA-production in GFM.     

Detection and identification of wild yeasts in Champús, a fermented Colombian maize beverage

The aim of this study was to identify and characterise the predominant yeasts in Champús, a traditional Colombian cereal-based beverage with a low alcoholic content.Samples of Champús from 20 production sites in the Cauca Valley region were analysed. A total of 235 yeast isolates were identified by conventional microbiological analyses and by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of ITS1-5.8S rDNA-ITS2. The dominant species were: Saccharomyces cerevisiae, Issatchenkia orientalis, Pichia fermentans, Pichia kluyveri var. kluyveri, Zygosaccharomyces fermentati, Torulospora delbruekii, Galactomyces geotrichum and Hanseniaspora spp. Model Champús systems were inoculated with single strains of some isolated sporogenus species and the aromatic profiles were analysed by SPME. Analysis of data showed that Champús strains produced high amounts of esters. The aromatic compounds produced by Saccharomyces and non-Saccharomyces yeasts from Champús can exert a relevant influence on the sensory characteristics of the fermented beverage. The Champús strains could thus represent an important source for new yeast biotypes with potential industrial applications.     

Sourdough fermented by Lactobacillus plantarum FST 1.7 improves the quality and shelf life of gluten-free bread

Lactobacillus plantarum FST 1.7 has been recently shown to produce antifungal compounds, which improve the shelf life of wheat bread. In the present study, this strain was investigated for its ability to improve the quality and shelf life of gluten-free bread. Effects of incorporation of sourdough fermented by strain FST 1.7 into a gluten-free bread mixture were compared to those obtained with sourdough fermented by the non-antifungal strain Lactobacillus sanfranciscensis TMW 1.52 as well as to those obtained with chemically or non-acidified batters. Fundamental rheological tests revealed that the addition of sourdough to the gluten-free mix led to an increase in firmness and increase in elasticity overtime (P < 0.05). Bread characteristics such as pH, total titratable acidity, and crumb hardness (5-day storage) were evaluated. Results showed that the biologically acidified gluten-free breads were softer after 5 days than the chemically acidified gluten-free breads (P < 0.001). Antifungal challenge tests employing conidial suspensions of Fusarium culmorum were carried out using the sourdough, non-acidified batter and bread. The rate of mould growth for the fungal species used was retarded by L. plantarum FST 1.7 when compared to the controls. In conclusion, the results of this study indicate that L. plantarum FST 1.7 can be used to produce gluten-free bread with increased quality and shelf life.     

Antioxidant and antibacterial activities of bioactive peptides in buffalo’s yoghurt fermented with different starter cultures

The effect of Lactobacillus acidophilus 20552 ATCC (T2) or Lactobacillus helveticus CH 5 (T3) in combination with yoghurt starter (1:1) on the antioxidant and antibacterial activities of the bioactive peptides present in buffalo’s yoghurt was studied. The SDS-PAGE results indicate that all caseins were completely hydrolyzed by both strains, whereas whey protein fractions were still present. All starter cultures have the ability to produce low-molecular-weight bioactive peptides, most of which were originated from β-casein and fewer from αs₁ casein. The antioxidant activity (%) of the water-soluble peptide extract from yoghurt samples increased in all samples during storage. Samples containing Lb. helveticus CH 5 showed the highest values. All yoghurt treatments displayed antibacterial activity against Escherichia coli. Control yoghurt and T3 showed higher antibacterial activity on E. coli, Staphylococcus aureus, and Bacillus cereus as compared to T2.     

Analysis of volatile compounds by GC–MS of a dry fermented sausage: chorizo de Pamplona

The profile of volatile compounds of a typical Spanish dry fermented sausage, chorizo de Pamplona, has been analyzed by GC–MS, using a simultaneous distillation-extraction (SDE) system. Qualitative and quantitative differences were found in the volatile profiles obtained in the five analyzed commercial brands. One hundred and ninety-three different substances were isolated, the group of acids being the most important from a quantitative point of view in all brands, accounting at least for the 60% of the total area. Aldehydes, basically from lipid oxidation, contributed between 7.72 and 13.97% to the total amount. Acids and aldehydes were the chemical families that showed the lowest variability among brands. In contrast, esters showed the highest coefficient of variation among brands (111%), followed by phenols (82%) and terpenes (76%). The variability observed in these three families could be attributed respectively to the different starter cultures, smoking process and spices employed in their production. Butylated hydroxytoluene (added as an antioxidant, E-321) was the third most abundant compound in three of the five brands.     

Diversity analysis and quantification of lactic acid bacteria in traditionally fermented yaks’ milk products from Tibet

Fermented yaks’ milk is a characteristic fermented dairy product with a rich microflora (especially lactic acid bacteria [LAB]), that has been produced by Tibetan people in China throughout history. Systematic analysis of the LAB composition of fermented yaks’ milk from central Tibet is essential. In the present study, 38 samples of fermented yaks’ milk were collected from three regions in central Tibet. From these, a total of 211 isolates of LAB were generated using traditional pure culture methods. To accurately analyze their biodiversity, 16S rRNA gene sequence analysis and denaturing gradient gel electrophoresis (DGGE) were used. The isolates were identified as belonging to six genera and 22 species/subspecies. Among them, Lactobacillus species predominated (117 isolates) accounting for 55.45% of all isolates. Overall, L. delbrueckii subsp. bulgaricus (60 isolates; 28.43% of the total) was the most commonly isolated species of LAB from fermented yaks’ milk from central Tibet. Seven Lactobacillus species and the Bifidobacterium genus were confirmed by quantitative PCR (q-PCR). The q-PCR results showed that the abundance of these groups in fermented yaks’ milk from central Tibet ranged from 1.12 ± 0.36 log cfu/ml (for L. sakei from Ningzhong) to 7.77 ± 0.84 log cfu/ml (for L. helvetivus from Ningzhong). Lactobacillus acidophilus, L. delbrueckii subsp. bulgaricus, L. fermentum, L. helveticus varied in concentration depending on the region. The results indicated that traditional fermented yaks’ milk from different regions of central Tibet have complex compositions of LAB species. The diversity of LAB might be related to geographical origin.     

Nitrite promotes protein carbonylation and Strecker aldehyde formation in experimental fermented sausages: Are both events connected?

The role played by curing agents (nitrite, ascorbate) on protein oxidation and Strecker aldehyde formation is studied. To fulfill this objective, increasing concentrations of nitrite (0, 75 and 150 ppm) and ascorbate (0, 250 and 500 ppm) were added to sausages subjected to a 54 day drying process. The concurrence of intense proteolysis, protein carbonylation and formation of Strecker aldehydes during processing of sausages suggests that α-aminoadipic semialdehyde (AAS) and γ-glutamic semialdehyde (GGS) may be implicated in the formation of Strecker aldehydes. The fact that nitrite (150 ppm, ingoing amount) significantly promoted the formation of protein carbonyls at early stages of processing and the subsequent formation of Strecker aldehydes provides strength to this hypothesis. Ascorbate (125 and 250 ppm) controlled the overall extent of protein carbonylation in sausages without declining the formation of Strecker aldehydes. These results may contribute to understanding the chemistry fundamentals of the positive influence of nitrite on the flavor and overall acceptability of cured muscle foods.     

Use of enterocin CCM 4231 to control Listeria monocytogenes in experimentally contaminated dry fermented Hornád salami

The effectiveness of enterocin CCM 4231 in controlling Listeria monocytogenes contamination in dry fermented Hornád salami was examined. Three independent salami treatments were conducted under pilot plant and laboratory conditions. Salamis were produced according to standard technological parameters and stages with ripening for 3 weeks. The reference samples consisted of the meat mixture without either L. monocytogenes or bacteriocin addition. The control sample (CS) consisted of the meat mixture with 1% of L. monocytogenes inoculum (10(8) cfu ml(-1)) added; while the experimental sample (ES) consisted of the same mixture with enterocin CCM 4231 (12800 AU g(-1)) added. Sampling was done on the first day of the experiment, before and after bacteriocin addition for ES, on the second day and after 1, 2 and 3 weeks. The enterocin addition resulted in the reduction of L. monocytogenes by 1.67 log cycle in the ES when compared to the CS immediately after addition of the bacteriocin. Although on the second day, the growth of L. monocytogenes in ES reached 3.38 cfu g(-1) (log 10), a difference of 1.72 log was found between the ES and the CS. After 1 week of ripening, the L. monocytogenes count in the CS reached 10(7) cfu g(-1); while in the ES the count was 10(4) cfu g(-1), a difference which was maintained after 2 and 3 weeks of ripening. However, bacteriocin activity in the ES could not be detected analytically. The meat mixture used did not contain Listeria.     

Ethyl carbamate in fermented foods and beverages: dietary exposure of the Hong Kong population in 2007–2008

To evaluate the potential public health risk of ethyl carbamate (EC), EC exposure from fermented foods and beverages for Hong Kong population was estimated. In 276 samples analysed, EC was detected (limit of detection (LOD) at 0.4?µg?kg^?1) in 202 samples (73%), with higher levels in fermented red bean curd (150–650?µg?kg^?1) and yellow wine (140–390?µg?kg^?1), while low or non-detected (ND) in preserved vegetables (ND–10?µg?kg^?1) and fermented tea (ND–15?µg?kg^?1). The estimated dietary exposure from all fermented foods and beverages was 8.27?ng?kg^?1?bw?day^?1, while exposure excluding alcoholic beverages was 5.42?ng?kg^?1?bw?day^?1, with calculated margins of exposure (MOEs) at 3.6?×?10⁴ and 5.5?×?10⁴ respectively. The risk of adverse health effects was low for the average population but higher (MOE?of?10³) for high consumers of alcoholic beverages especially habitual drinkers of alcoholic types with high EC contents.     

Characterisation of the microflora of attiéké, a fermented cassava product, during traditional small-scale preparation

Attiéké is a fermented cassava product consumed mainly in Cote d'Ivoire. The aim of this study was to characterise the attiéké fermentation by examining products from 15 small-scale production sites at various stages of its preparation. For the preparation of attiéké, fresh cassava is grated to a pulp and inoculated with 10% of a spontaneous traditional inoculum. The inocula contained aerobic mesophiles at mean numbers of 8.2 x 10(7) cfu/g and lactic and acetic acids at mean concentrations of 0.2% and 0.1%, respectively. The mean pH was 5.0. Lactic acid bacteria were the dominant microorganisms in cassava pulp throughout fermentation with the mean numbers being 1.2 x 10(9) cfu/g after 15 h. The identification to the species level of microorganisms from one representative attiéké production of good quality showed that, at the start of fermentation, Leuconostoc mesenteroides subsp. mesenteroides was present in the highest numbers, accounting for 20% of all lactic acid bacteria. As the fermentation proceeded, this species was replaced by homofermentative lactic acid bacteria, Lactobacillus salivarius and Lactobacillus delbrueckii subsp. delbrueckii, present at 20% and 16%, respectively, and obligate heterofermentatives, Lactobacillus fermentum and Lactobacillus confusus at 12% and 10%, respectively, of total lactic acid bacteria in the flora at the end of fermentation. High numbers of acid-sensitive microorganisms, Bacillus circulans, Bacillus lentus, Enterobacter sakazakii, Enterobacter cloacae and Klebsiella pneumoniae subsp. pneumoniae, were transferred to the pulp in the inocula, but acidification to a mean pH of 4.4 with mean lactic and acetic acid concentrations of 0.59% and 0.2%, respectively, prevented their growth and reduced their numbers to less than 10(2) cfu/g at the end of fermentation. The mean numbers of Candida tropicalis, the main yeast present, remained relatively constant at about 10(5) cfu/g throughout attiéké production. The mean numbers of aerobic mesophiles decreased to below 10(2) cfu/g as a result of the steaming process. The finished attiéké had a mean pH of 4.4 and mean lactic and acetic acid concentrations of 0.6% and 0.1%, respectively.     

Antibiotic resistance and virulence factors among Enterococci isolated from chouriço, a traditional Portuguese dry fermented sausage

Enterococci are ubiquitous microorganisms, found as part of the normal intestinal microbiota of many animals. They can be present in food products, for example, the Portuguese dry fermented sausage chouri?o. Twenty enterococci were isolated from chouri?o in two processing units; after identification and typification by conventional-molecular methods, the isolates were screened for virulence factors and antibiotic resistance. Identification allocated all enterococci to the species Enterococcus faecalis, and PCR fingerprinting demonstrated that each isolate was specific to the processing unit and chouri?o from which it was recovered. Regarding the screening for virulence factors, 1 strain produced cytolysin and 4 were gelatinase positive, but none produced lipase. The ace gene was detected in 1 enterococci, ebpABC and efaA(fs) in 16 isolates each, esp in 3, fsrB in 5, gelE in 7, and cylA in 1. A multiresistant phenotype was observed in 8 isolates, 6 belonging to factory A. The antibiotic resistance gene ere(B) was detected in 9 enterococci, whereas the genes tet(M), aac(6')-Ie-aph(2'), and vanA were detected in 8 isolates each. As some of the E. faecalis chouri?o isolates present a multiresistant profile and harbor virulence and/or resistance genes, to assess further the safety of Portuguese dry sausages, a larger number of products and processing units must by analyzed.     

Effect of adzuki bean sprout fermented milk enriched in γ-aminobutyric acid on mild depression in a mouse model

This study focused on the ability of adzuki bean (Vigna angularis) sprout fermented milk, which is rich in γ-aminobutyric acid (GABA), to relieve anxiety and mild depression. A high-yield GABA-producing strain, Lactobacillus brevis J1, from a healthy cow was screened, and its physiological and probiotic properties were evaluated. The effect of adzuki bean sprout fermented milk was investigated in vivo in a chronic depression mouse model. The results showed that Lb. brevis J1 had excellent probiotic properties, grew well at low pH and 3% NaCl, and adhered to the surface of HT-29 cells. The GABA-enriched (241.30 ± 1.62 µg/mL) adzuki bean sprout fermented milk prepared with Streptococcus thermophilus, Lactobacillus bulgaricus, and Lactobacillus plantarum, and Lb. brevis J1 can reduce and possibly prevent mild depression-like symptoms in mice (C57/B6) by increasing social interaction and enhancing the pleasure derived from movement. The research revealed that the GABA_B-cyclic AMP-protein kinase A-cAMP-response element binding protein (GABA_B-cAMP-PKA-CREB) signaling pathway was related to the depression-like symptoms and that levels of 5-hydroxytryptamine, norepinephrine, and dopamine in the hippocampus of mice increased after treatment with the adzuki bean sprout fermented milk. Our results suggest that GABA-enriched dairy products have the potential to prevent or treat mild depression-like symptoms in mice, which suggests a new approach for a dietary therapy to treat chronic social stress.     

Effect of starter culture and storage temperature on the content of biogenic amines in dry fermented sausage poličan

Water activity, pH, microbial counts (total counts/TCM/, coliforms, Enterobacter, Proteus, Pseudomonas, Escherichia and Lactobacillus spp., respectively), and seven biogenic amines (BA) were determined in dry fermented sausage 'poli?an' produced using starter culture A (Lactobacillus sakei, Staphylococcus carnosus, S. xylosus) or B (L. sakei, S. carnosus, Pediococcus pentosaceus), ripened 42 days, and subsequently stored at 8 or 22°C 60 days. Counts of lactobacilli were higher and TCM lower in the A-sausage when ripening was finished. Tyramine (quantitatively most important BA) content was not different (P>0.05) in A- (90 mg/kg of dry matter, DM) or B-sausage (91 mg/kg DM) at the end of ripening. The effect of the storage temperature on BA content was not significant (P>0.05) in the case of either tyramine or any other tested BA. The increase of total BA content during ripening was not different (P>0.05) between A- and B-sausages (final value 190 and 222 mg/kg DM, respectively). However, sum of BA was significantly higher (P<0.05) in B-sausage as compared with A-sausage at the end of either refrigerated storage (304 and 236 mg/kg DM) or room temperature storage (468 and 206 mg/kg DM, respectively). It is concluded that legislative limits should be established for tyramine and total BA content in dry fermented meat products.