Lactic Acid Bacteria Fermentation Research Articles

Study on the functional properties and structural characteristics of soybean soluble polysaccharides by mixed bacteria fermentation and microwave treatment

The soybean soluble polysaccharide was prepared by mixed fermentation of lactic acid bacteria and Neurospora crassa and microwave treatment. The functional properties and structure characteristics of soybean soluble polysaccharide before and after modification were compared. Results revealed that after fermentation treatment, the content of soybean soluble polysaccharide increased to 7.09%, which was 3.16 times that of raw materials, and the microwave treatment was further increased to 7.69%. The glucose adsorption capacity, glucose dialysis retardation index and the α-amylase activity inhibition ration of soybean soluble polysaccharides increased significantly, promotes intestinal flora growth in vitro after fermentation of mixed bacteria and microwave treatment. At the same time, the analysis of monosaccharide composition and structural characteristics showed that the monosaccharide components of soybean soluble polysaccharide were redistributed after modification treatment, Scanning electron microscopy showed that modified soybean soluble polysaccharide has a larger surface area; Fourier Transform Infrared spectroscopy and X-ray Diffraction proved that the modification has slight changes in the functional groups and crystal structure of soybean soluble polysaccharide. These results suggested that okara may be a potentially inexpensive source of natural soybean soluble polysaccharide and a potential functional food ingredient.

Heating Effect on Rumen Digestion of Protein Feeds Fermented by Lactid Acid Bacteria

This study aimed to measure the in vitro digestibility of protein feeds as a product of Lactic acid bacteria (LAB) fermentation with different levels of molasses addition and incubation time. The LAB fermentation of protein feeds experiment had treatments given in the form of addition of molasses with levels of 0%, 3%, and 5% as well as at different incubation times of 0, 1, and 2 weeks. The best result of LAB fermentation was then protected from the rumen digestion by a heating treatment, carbohydrate, and fat addition. The parameter observed includes levels of pH and lactic acid production for LAB fermentation of protein feeds experiment and dry matter (DMD), organic matter (OMD), and crude protein digestibility (CPD) for protected rumen digestion experiment. Result showed that the lowest pH were 4.65±0.02, reached at the treatment with one week incubation (p<0.05) and 0% molasses addition (p<0.05). The highest lactic acid content were 1.82±0.10 mg/g fermentation feed based on treatment one weeks incubation (p<0.05) and 0% molasses addition (p>0.05). The highest content of protein showed at the treatment with two weeks incubation (p>0.05) and 5% molasses addition (p<0.05). Heating treatment had no significant compared to control, with the result respectively DMD 42.48±4.08%; 38.62±6.31%, OMD 53.21±4.74%; 49.71±5.62%, and CPD 38.15±4.71%; 34.88±2.72% (p>0.05). Fermentation could improve the nutrient quality of concentrate, but further research is needed to find ways to protect fermented concentrate.

Production of Lactic Acid from Seaweed Hydrolysates via Lactic Acid Bacteria Fermentation

Biodegradable polylactic acid material is manufactured from lactic acid, mainly produced by microbial fermentation. The high production cost of lactic acid still remains the major limitation for its application, indicating that the cost of carbon sources for the production of lactic acid has to be minimized. In addition, a lack of source availability of food crop and lignocellulosic biomass has encouraged researchers and industries to explore new feedstocks for microbial lactic acid fermentation. Seaweeds have attracted considerable attention as a carbon source for microbial fermentation owing to their non-terrestrial origin, fast growth, and photoautotrophic nature. The proximate compositions study of red, brown, and green seaweeds indicated that Gracilaria sp. has the highest carbohydrate content. The conditions were optimized for the saccharification of the seaweeds, and the results indicated that Gracilaria sp. yielded the highest reducing sugar content. Optimal lactic acid fermentation parameters, such as cell inoculum, agitation, and temperature, were determined to be 6% (v/v), 0 rpm, and 30 °C, respectively. Gracilaria sp. hydrolysates fermented by lactic acid bacteria at optimal conditions yielded a final lactic acid concentration of 19.32 g/L.

Engineering Tools for the Development of Recombinant Lactic Acid Bacteria.

Lactic acid bacteria (LAB) is mainly used in food fermentation. In addition, LAB fermentation technology has been studied in the development of industrial food additives, nutrients, or enzymes used in food processing. In the field of red biotechnology, LAB is approved and is generally recognized as a safe organism and is considered safe for biotherapeutic treatments. Recent clinical trials have demonstrated the medicinal value of therapeutic recombinant LAB and the suitability of innate mechanisms of secretion and anchoring for therapeutic applications such as antibody or vaccine production. However, the gram-positive phenotypic trait of LAB creates challenges for genetic modifications when compared to other conventional workhorse bacteria, resulting in exclusive developments of genetic tools for engineering LAB. In this review, several distinct approaches in gene expression for engineering LAB are discussed.

Application of mannitol producing Leuconostoc citreum TR116 to reduce sugar content of barley, oat and wheat malt-based worts

Achieving a high monosaccharide composition in malt wort is instrumental to achieve successful lactic acid bacteria fermentation of malt based beverages. The conversion of monosaccharides to alternative metabolites such as the sweet polyol, mannitol with heterofermentative strains presents a novel approach for sugar reduction and to compensate for the loss of sweetness. This work outlines the application of an adopted mashing regimen with the addition of exogenous enzymes to produce wort with high fructose content which can be applied to different malted grain types with consistently efficacious monosaccharide production for bacterial fermentation. The so produced worts are then fermented with Leuconostoc citreum TR116 a mannitol hyper-producer. Malted barley, oat and wheat were mashed to stimulate protein degradation and release of free amino acids along with the enzymatic conversion of starch to fermentable sugars. Amyloglucosidase and glucose isomerase treatment converted di- and oligo-saccharides to glucose and provided a moderate fructose concentration in malt worts which was consistent across the three cereals. Fructose was completely depleted during fermentation with Lc. Citreum TR116 and converted to mannitol with high efficiency (>90%) while overall sugar reduction was >25% in all malt worts. Differences in amino acid composition of malt worts did not significantly affect growth of Lc. Citreum TR116 but did affect the formation of the aroma compounds diacetyl and isoamyl alcohol. Organic acid production and acidification of wort was similar across cereal substrates and acetic acid formation was linked to yield of mannitol. The results suggest that differences in amino acid and fructose content of malt worts considerably change metabolite formation during fermentation with Lc. Citreum TR116, a mannitol hyper-producer. This work gives new insight into the development of consumer acceptable malt based beverages which will provide further options for the health conscious and diabetic consumer, an important step in the age of sugar overconsumption.

Multi-Product Lactic Acid Bacteria Fermentations: A Review

Industrial biotechnology is a continuously expanding field focused on the application of microorganisms to produce chemicals using renewable sources as substrates. Currently, an increasing interest in new versatile processes, able to utilize a variety of substrates to obtain diverse products, can be observed. A robust microbial strain is critical in the creation of such processes. Lactic acid bacteria (LAB) are used to produce a wide variety of chemicals with high commercial interest. Lactic acid (LA) is the most predominant industrial product obtained from LAB fermentations, and its production is forecasted to rise as the result of the increasing demand of polylactic acid. Hence, the creation of new ways to revalorize LA production processes is of high interest and could further enhance its economic value. Therefore, this review explores some co-products of LA fermentations, derived from LAB, with special focus on bacteriocins, lipoteichoic acid, and probiotics. Finally, a multi-product process involving LA and the other compounds of interest is proposed.

Characterization of lactic acid bacteria isolated from a traditional Ivoirian beer process to develop starter cultures for safe sorghum-based beverages

The present study aimed to characterize lactic acid bacteria involved in the different processing steps of tchapalo, a traditional Ivoirian beverage, for their potential application as starter cultures in food and beverages. Lactic acid bacteria (LAB) were therefore isolated and enumerated at different steps of the process on MRS and BEA agars. Of the 465 isolates, 27 produced bacteriocins that inhibit Lactobacillus delbrueckii F/31 strain. Of those, two also inhibited Listeria innocua ATCC 33090, while two others displayed inhibitory activity against L.innocua ATCC 33090, E. faecalis CIP 105042, E. faecalis ATCC 29212, Streptococcus sp. clinical LNSP, E. faecalis CIP 105042 and E. faecium ATCC 51558. The dominant species involved in tchapalo LAB fermentation, as determined by 16S rRNA gene sequencing, were Lactobacillus fermentum (64%), followed by Pediococcus acidilactici (14%). Two strains representing the two dominant species, L. fermentum S6 and P. acidilactici S7, and two potential bacteriocin producers, Weissella confusa AB3E41 and Enterococcus faecium AT1E22, were selected for further characterization. First, genome analysis showed that these strains do not display potential harmful genes such as pathogenic factors or transmissible antibiotic resistance genes. Furthermore, phylogenetic analyses were performed to assess evidence of eventual links to groups of strains with particular properties. They revealed that (i) L. fermentum S6 and P. acidilactici S7 are closely related to strains that ferment plants, (ii) E. faecium AT1E22 belongs to the environmental clade B of E. faecium, while W. confusa is quite similar to other strains also isolated from plant fermentations. Further genome analysis showed that E. faecium AT1E22 contains the Enterocin P gene probably carried by a megaplasmid, whereas no evidence of a bacteriocin gene was found in W. confusa AB3E41. The metabolic and the first step of the probiotic potentials of the different strains were analyzed. Lactobacillus fermentum S6 and P. acidilactici S7 are good candidates to develop starter cultures, and E. faecium AT1E22 should be further tested to confirm its potential as a probiotic strain in the production of sorghum wort.

Effects of lactic acid fermentation-based biotransformation on phenolic profiles, antioxidant capacity and flavor volatiles of apple juice

Apple juice (AJ) was fermented by six select lactic acid bacteria (LAB), namely Lactobacillus plantarum 90 (Lp90), Lactobacillus helveticus 76 (Lh76), Lactobacillus casei 37 (Lc37), Lactobacillus paracasei 01 (Lpc01), Lactobacillus acidophilus 85 (La85) and Bifidobacterium lactis 80 (Bla80). The effects of LAB fermentation on sugars and organic acids contents, phenolic profiles, antioxidant capacity and flavor volatiles of fermented AJ (FAJ) were investigated. Results showed that AJ was an excellent food matrix for LAB strains. Lh76 and Lp90 showed the highest viable counts of 12.7 log CFU/mL at the end of fermentation. Lp90, La85 and Bla80 exhibited strong malolactic conversion capacity and finally produced lactic acid more than 6.5 mg/mL. In addtion, LAB fermentation significantly (p < 0.05) decreased the total phenols and flavonoids levels. However, antioxidant activities based on DPPH and FRAP methods were enhanced during fermentation, especially for La85 which exhibited dramatical DPPH radical scavenging activity (90.05%) and FRAP (0.96 mmol Trolox/L). The improvement of antioxidant activities was suggested to be related to the increase in caffeic acid and phlorizin contents. The analysis of flavor volatiles showed that LAB fermentation resulted in formation of seven new alcohols and six new esters, and improvement of ketones and aldehydes production.

Synergistic Effect of the Lactic Acid Bacteria and Salt Coagulant in Improvement of Quality Characteristics and Storage Stability of Tofu.

In this study, a new way to produce tofu with lactic acid bacteria (Lactobacillus casei, L. casei) and salt coagulant (magnesium sulfate) has been developed and optimized in order to improve the quality characteristics and the storage stability. Processing parameters (bean-water ratio, inoculation amount, magnesium sulfate concentration and pressing time) of tofu were studied. Yield, water holding capacity (WHC), texture and sensory were measured for evaluating quality characteristics of tofu. Based on the single factor and response surface methodology (RSM), the optimized conditions of tofu were determined as follows: bean-water ratio was 1:4 g/mL, fermentation time was 5 h at 37°C when the inoculation amount was 4.0%, magnesium sulfate concentration was 2.0 mol/L and pressing time was 1 h. Under the optimum conditions, the yield of the tofu was 140.45 g, the WHC was 87.25 %, the hardness was 420.36 g, and the tofu had better sensory characteristics, soft, uniform texture, as well as good flavor. The shelf life and stability of tofu during storage were also evaluated under the optimum conditions. The results showed that fermented tofu had a longer shelf life than unfermented tofu at room temperature. Compared with the "pasteurization + low temperature" group and "low temperature" group, the fermented tofu in the "microwave + low temperature" group had a longer shelf life and better-quality properties during storage. Tofu, prepared by the lactic acid bacteria fermentation and salt coagulant, would be accepted as a new type of tofu according to its quality characteristics and storage stability.

Secondary Lactic Acid Bacteria Fermentation with Wood-Derived Xylooligosaccharides as a Tool To Expedite Sour Beer Production.

Xylooligosaccharides (XOS) from woody biomass were evaluated as a substrate for secondary lactic acid bacteria (LAB) fermentation in sour beer production. XOS were extracted from birch (Betula pubescens) and added to beer to promote the growth of Lactobacillus brevis BSO 464. Growth, pH, XOS degradation, and metabolic products were monitored throughout fermentations, and the final beer was evaluated sensorically. XOS were utilized, metabolic compounds were produced (1800 mg/L lactic acid), and pH was reduced from 4.1 to 3.6. Secondary fermentation changed sensory properties significantly, and the resulting sour beer was assessed as similar to a commercial reference in multiple attributes, including acidic taste. Overall, secondary LAB fermentation induced by wood-derived XOS provided a new approach to successfully produce sour beer with reduced fermentation time (from 1-3 years to 4 weeks). The presented results demonstrate how hemicellulosic biomass can be valorized for beverage production and to obtain sour beer with improved process control.

Use of Fermented Hemp, Chickpea and Milling By-Products to Improve the Nutritional Value of Semolina Pasta.

A biotechnological approach including enzymatic treatment (protease and xylanase) and lactic acid bacteria fermentation has been evaluated to enhance the nutritional value of semolina pasta enriched with hemp, chickpea and milling by-products. The intense (up to circa, (ca.) 70%) decrease in the peptide profile area and (up to two-fold) increase in total free amino acids, compared to the untreated raw materials, highlighted the potential of lactic acid bacteria to positively affect their in vitro protein digestibility. Fermented and unfermented ingredients have been characterized and used to fortify pasta made under pilot-plant scale. Due to the high contents of protein (ca. 13%) and fiber (ca. 6%) and according to the Regulation of the European Community (EC) No. 1924/2006 fortified pasta can be labelled as a “source of fiber” and a “source of protein”. The use of non-wheat flours increased the content of anti-nutritional factors as compared to the control pasta. Nevertheless, fermentation with lactic acid bacteria led to significant decreases in condensed tannins (ca. 50%), phytic acid and raffinose (ca. ten-fold) contents as compared to the unfermented pasta. Moreover, total free amino acids and in vitro protein digestibility values were 60% and 70%, respectively, higher than pasta made only with semolina. Sensory analysis highlighted a strong effect of the fortification on the sensory profile of pasta.

Effects of different simulated seasonal temperatures on the fermentation characteristics and microbial community diversities of the maize straw and cabbage waste co-ensiling system

Ensiling is considered as a suitable method to preserve seasonal agricultural residues to enable long-term supply for wastes valorization. In this study, the effects of simulated seasonal temperatures (−3, 18 and 34 °C) on the organic compositions, ensiling fermentation characteristics, and microbial community evolution during 120 days co-ensiling of maize straw and cabbage wastes were investigated. Successful storage performance was obtained at all these three temperatures. Comparatively, silages at 18 and 34 °C showed lower ammonia nitrogen, lower pH and more intensive lactic acid bacteria fermentation than that at −3 °C. Both silages at −3 and18 °C were well-preserved for 120 days with higher biodegradation potential (BDP), accompanied by lower content of acid detergent lignin (ADL). However, the silages at 34 °C could only preserved for 90 days due to low carbohydrate, low BDP and higher ADL content than that at −3 or18 °C. The storage temperature is a critical parameter that significantly affected the silage quality by influencing the microbial community diversity in silages. Proteobacteria and Firmicutes were dominant bacteria at phylum level for all silages while the dominant lactic acid bacteria at genus level were Lactobacillus and Leuconostoc, which restrained the undesirable microbes such as Enterobacteriaceae, Pseudomonas, Flavobacterium, and Pantoea during co-ensiling. Co-ensiling of maize straw with vegetable wastes may provide a promising strategy for long-term preservation of air-dried crop straw while using vegetable wastes as regulatable supplement to achieve silages of desired quality. This study could provide valuable information for conservation and management of agricultural wastes.

Nutritional and functional effects of the lactic acid bacteria fermentation on gelatinized legume flours

Aiming at meeting recent consumers requirements in terms of high nutritional value and functional foods, the cereal food industry has proposed the use of legumes as wheat substitutes due to the high contents of proteins with high biological value and dietary fibers. Nevertheless, legumes contain several anti-nutritional factors which may limit the bio-availability of several nutrients. In this study, an integrate biotechnological approach, combining a thermal treatment (“gelatinization”) and fermentation with selected lactic acid bacteria, was set-up in order to improve the functional and nutritional quality of red and yellow lentils, white and black beans, chickpeas and peas flours. Gelatinization carried out at pilot-plant level on legume grains before milling, affected the nutritional properties of the flours by the increase of protein digestibility, resistant starch formation, the decrease of trypsin inhibitors, although negatively affecting the antioxidant activity. Fermentation with Lactobacillus plantarum MRS1 and Lactobacillus brevis MRS4 further enhanced the nutritional properties of processed legume flours through the increase of free amino acids concentration and protein digestibility, the degradation of phytic acid, condensed tannins and raffinose, and the decrease of the trypsin inhibitory activity and starch hydrolysis index. Moreover, fermentation also contributed to the increase of the radical scavenging activity of both raw and processed legumes.

The effect of addition of turmeric (Curcuma longa L.) on the rancidity process of concentrate feed based on lactic acid bacteria fermentation during aerobic storage

This study aimed to determine the effect of the addition of turmeric (Curcuma longa L.) on rancidity process of concentrate feed based on lactic acid bacteria fermentation (CFLAB) in aerobic storage conditions. The treatments were the addition of turmeric extract, turmeric flour, and vitamin E in feed with levels of 0, 0.5, 1, 1.5, 2 and storage for 0, 10, 20, 30, 40 days with three replications. Antioxidant activity was carried out by 2.2-diphenyl-1-picrylhydrazyl analysis. The pH, free fatty acids numbers (FFA), and organoleptic analysis were determined in CFLAB quality during storage. DPPH analysis showed that turmeric extract and vitamin E had the best antioxidant activity. Addition of 2% turmeric extract, 2% turmeric flour, and 2% vitamin E lowered the pH. The addition of antioxidant compounds decreased FFA levels compared to controls except for the addition of vitamin E, but in terms of the percentage increase in FFA levels during storage, the addition of 1,5% turmeric flour gave the best results. Physical quality in the form of color, odor, texture, and fungus indicated that the quality of the CFLAB was able to keep in good condition due to the antioxidant sources addition.

The effect of aerated storage system and turmeric (Curcuma longa L.) addition on the quality of lactic acid bacteria fermented feed

This study determined the effect of turmeric (Curcuma longa L.) in preventing the rancidity process of concentrate feed based on lactic acids bacteria fermentation (CFLAB) in aerated aerobic storage conditions. The treatments were the addition of pure turmeric, extract turmeric, and vitamin E in feed with the level of 0, 0.5, 1, and 2%, with three replications. Aeration was done every morning and evening for 40 days. Rancidity observation was carried out after 40 days. The parameters observed were pH values, numbers of free fatty acids (FFA), and physical quality. The addition of antioxidant sources during aerated aerobic storage affected the FFA content. The addition of three sources and five levels of antioxidant sources maintain a pH value in the neutral range during storage. Based on the FFA analysis, the addition of turmeric and turmeric extract was suppressed increasing of FFA value better than control and vitamin E. This research concludes that the provision of antioxidant sources inhibit the increasing levels of FFA during storage. The results of the organoleptic test showed that the quality of CFLAB persisted quite well in all treatments with aerated aerobic on 40 days storage.

산돌배 과실 추출물의 젖산균 혼합발효를 통한 고농도 GABA 생산

γ-Aminobutyric acid (GABA) was produced by the sequential fermentation of the fruit extract of Pyrus ussuriensis Maximowicz (PFE) with two strains of lactic acid bacteria. The soluble solid content of the PFE was 5.25 oBrix and it also displayed a high potassium content of 127.6 mg/100 g. The first lactic acid fermentation of PFE was performed with Leuconostoc citreum S5 at 25℃ for 2 days. Subsequently, the second lactic acid fermentation was carried out with the first fermented PFE fortified with 3% monosodium ʟ-glutamate (MSG) by Lacobacillus plantarum EJ2014 at 30℃ for 5 days. During the first fermentation, the pH of the PFE medium decreased from 4.42 to 4.19 and the acidity increased from 0.28% to 1.03%. After the second fermentation, pH was 4.64 and acidity was 1.23%. The viable cell counts of Lc. citreum S5 and L. plantarum EJ2014 were 7.94 log CFU/mL and 9.18 log CFU/mL, respectively. The amount of the reducing sugar in PFE increased during the first fermentation period and was nearly consumed during the 2nd fermentation. Notably, MSG was successfully converted into 1.78% of GABA during the second fermentation. In conclusion, high yield for production of GABA was achieved by a novel mixed fermentation of lactic acid bacteria, which highlights PFE as a functional food material.

Brans from hull-less barley, emmer and pigmented wheat varieties: From by-products to bread nutritional improvers using selected lactic acid bacteria and xylanase

Aiming at meeting the recommendations of the World Health Organization regarding the total fiber daily intake, an integrate biotechnological approach, combining xylanase treatment and lactic acid bacteria fermentation of milling by-products from pigmented wheat varieties, hull-less barley and emmer was proposed. The effects on the biochemical and nutritional features were investigated. Enhanced radical scavenging activity, increased concentrations of free amino acids (up to three times) and peptides and optimal in vitro protein digestibility (up to ca. 87%) value as well as relevant phytic acid degradation were achieved during bran fermentation. The main nutritional features of each matrix were enhanced and distinguished. Fortified breads were characterized by a concentration in total dietary fibers and protein of ca. 7 and 13% of dry matter, respectively. Compared to wheat bread the addition of pre-fermented brans caused a significant increase in protein digestibility (up to 79%), and a relevant decrease of the predicted glycemic index (ca. 8%) of the fortified bread. According to the results, this study demonstrates the potential of xylanase treatment and lactic acid bacteria fermentation to be used as suitable strategy to include bran in breadmaking, meeting both nutritional and sensory requests of modern consumers.

Fermentation of onion (Allium cepa L.) peel by lactic acid bacteria for production of functional food

Onion (Allium cepa L.) peel is rich in flavonoids (e.g. quercetin), which have attracted interest for their beneficial health effects, including antioxidative and anti-inflammatory activities, but it is usually discarded. This study tested a potential way to utilize onion peel, by producing a functional food by fermentation with lactic acid bacteria (LAB). Of 13 Lactobacillus strains tested, five (E19, E31, J11, J41, and 361) reached viable cell counts > 108 CFU/mL. LAB fermentation did not affect the quercetin content of onion peel. Five strains inhibited the activity of angiotensin I-converting enzyme, which converts angiotensin I into angiotensin II, a potent vasoconstrictor that regulates blood pressure. We selected Lactobacillus plantarum E31 for further study, and onion peel fermented by using this strain inhibited the enzyme activity. Analysis with a taste-sensing system showed that fermentation with strain E31 produced onion peel that was more acidic and had less umami flavor and aftertaste of anionic bitterness than unfermented samples. This study proposes a new approach to utilize a food by-product by adding value via production of a new functional food—fermented onion peel—which contains both flavonoids and probiotics.

Study on Fermentation Process of Lactic Acid Bacteria Inoculated with Kimchi

This paper uses cabbage as raw material to ferment kimchi through lactic acid bacteria inoculation. Using sensory score, total acid, pH and nitrite content as indicators, the main factors affecting the fermentation of lactic acid bacteria inoculated kimchi were investigated. The optimum technological conditions for inoculating fermentation of Kimchi lactic acid bacteria were determined by experiments. The lactic acid bacteria grow rapidly during the fermentation process and produce lactic acid, which lowers the pH value of the kimchi. The protein in the kimchi is decomposed into free amino acids, and the calcium ions are combined into inorganic salts, which have high nutritional value.

Effects of LAB fermentation on the quality of grass carp Fillet

Over a 7 days’ fermentation process, LAB (lactic acid bacteria) fermentation improved sensory characteristics such as hardness, springiness, adhesiveness, chewiness and resilience. The effects of the two LAB strains combination showed better than that of either single strain because of their synergy in growth and acid production. The results demonstrated that LAB cultures could be developed as fermentation starter and bio-preservative to improve the quality of grass carp in storage, and combination of synergetic LAB strains more promising.