scholarly journals Technological characterization of lactic acid bacteria isolated from sheep milk for potential use as non-starter cultures

2019 ◽  
Vol 74 (1) ◽  
pp. 13-24
Author(s):  
Maria Rita Souto Dias ◽  
Andressa Fusieger ◽  
Amanda De Souza Motta

O leite de ovelha possui diferentes propriedades físico-químicas, o que significa que seus derivados têm alto valor agregado. Parte dessas propriedades é conferida por bactérias lácticas que desempenham importantes atividades no leite cru. Esta pesquisa teve como objetivo analisar cinco bactérias lácticas previamente identificadas e avaliadas quanto a seus parâmetros de acidificação, proteólise, produção de diacetil e exopolissacarídeos, potencial atividade antimicrobiana e parâmetros de segurança. A identificação do gene 16S rDNA por sequenciamento mostrou concordância com os dados obtidos por MALDI-TOF/MS. As bactérias foram identificadas como Lactococcus lactis MRS1, Lactococcus lactis MRS2, Lactococcus lactis MRS5, Lactococcus lactis MRS6 e Enterococcus faecalis M173. Todos os isolados apresentaram o mesmo perfil de acidificação, mantendo o pH em 4,5 a partir de 6 horas de incubação, nas condições empregadas. Atividade proteolítica, capacidade de coexistência e produção de exopolissacarídeos foram observadas em todos os isolados testados. A produção de diacetil foi evidente nos isolados Lactococcus lactis MRS1 e Lactococcus lactis MRS2. Em relação à presença de atividade antimicrobiana, os isolados de Lactococcus lactis MRS6 e Enterococcus faecalis M173 inibiram todas as culturas testadas. Na avaliação dos parâmetros de segurança, nenhum dos isolados apresentou resistência de alto nível a antibióticos clinicamente importantes e não apresentaram produção de gelatinase e atividade hemolítica. Estes resultados fornecem uma informação importante sobre as potenciais bactérias a serem exploradas para a aplicação em produtos derivados de leite de ovelha, em condições de cultura starter ou adjuntas.

2020 ◽  
Vol 8 (11) ◽  
pp. 1689 ◽  
Author(s):  
Vera Fraberger ◽  
Martin Ladurner ◽  
Alexandra Nemec ◽  
Clemens Grunwald-Gruber ◽  
Lisa M. Call ◽  
...  

Sourdough processing contributes to better digestible wheat-based bakery products, especially due to the proteolytic activity of lactic acid bacteria (LAB). Therefore, sourdough-related LAB were screened for their capacity to degrade immunogenic proteins like gluten and alpha-amylase-trypsin inhibitors (ATIs). Firstly, the growth of 87 isolates was evaluated on a gluten-based medium. Further, the breakdown capacity of selected isolates was determined for gluten with a focus on gliadins by measuring acidification parameters and MALDI-TOF MS protein profiles. ATI degradation after 72 h of incubation within an ATI-based medium was investigated by means of acidification, HPLC, and competitive ELISA. All isolates exhibited the potential to degrade ATIs to a high degree, whereas the gliadin degradation capacity varied more greatly among tested LAB, with Lacticaseibacillus paracasei Lpa4 exhibiting the strongest alterations of the gliadin pattern, followed by Lactiplantibacillus plantarum Lpl5. ATI degradation capacities ranged from 52.3% to 85.0% by HPLC and 22.2% to 70.2% by ELISA, with Lacticaseibacillus paracasei Lpa4 showing superior breakdown properties. Hence, a selection of specific starter cultures can be used in sourdough processing for wheat-based bakery products with reduced gluten and ATI content and, further, better tolerated products for patients suffering from non-celiac wheat sensitivity (NCWS).


2020 ◽  
Vol 322 ◽  
pp. 108547 ◽  
Author(s):  
Solange Aka ◽  
Bedis Dridi ◽  
Alexandre Bolotin ◽  
Elysée Armel Yapo ◽  
Marina Koussemon-Camara ◽  
...  

2001 ◽  
Vol 64 (4) ◽  
pp. 559-563 ◽  
Author(s):  
ROXANA MEDINA ◽  
MARTA KATZ ◽  
SILVIA GONZALEZ ◽  
GUILLERMO OLIVER

Indigenous lactic acid bacteria in ewe's milk and artisanal cheese were studied in four samples of fresh raw milk and four 1-month-old cheeses from the provinces of northwest Argentina. Mean growth counts on M17, MRS, and MSE agar media did not show significant differences (P < 0.05) in raw milk and cheeses. Isolates of lactic acid bacteria from milk were identified as Enterococcus (48%), lactococci (14%), leuconostocs (8%), and lactobacilli (30%). All lactococci were identified as Lactococcus lactis (subsp. lactis and subsp. cremoris). Lactobacilli were identified as Lactobacillus plantarum (92%) and Lactobacillus acidophilus (8%). Enterococci (59%) and lactobacilli (41%) were isolated from cheeses. L. plantarum (93%), L. acidophilus (5%), and Lactobacillus casei (2%) were most frequently isolated. L. lactis subsp. lactis biovar diacetylactis strains were considered as fast acid producers. L. lactis subsp. cremoris strains were slow acid producers. L. plantarum and L. casei strains identified from the cheeses showed slow acid production. The majority of the lactobacilli and Lactococcus lactis strains utilized citrate and produced diacetyl and acetoin in milk. Enzyme activities (API-ZYM tests) of lactococci were low, but activities of L. plantarum strains were considerably higher. The predominance of L. plantarum in artisanal cheese is probably important in the ripening of these cheeses due to their physiological and biochemical characteristics.


Author(s):  
Maria Tereza Pereira ◽  
Elsa Helena Walter de Santana ◽  
Joice Sifuentes dos Santos

Produtos lácteos fermentados contêm bactérias ácido lácticas (BAL), naturalmente presentes ou adicionadas na matriz láctea como culturas iniciadoras (starters), contribuindo com aroma, textura, valor nutricional e segurança microbiológica. Lactobacillus spp., Streptococcus spp., Lactococcus spp. e Leuconostoc spp. são utilizados como culturas starters em laticínios. As BAL podem ser classificadas em mesofílicas (ex Lactococcus lactis) e termofílicas (ex Streptococcus thermophilus), e de acordo com seus metabólitos de fermentação em homofermentativas (ácido lático) e heterofermentativas (ácido lático, dióxido de carbono, diacetil e outros compostos flavorizantes). Entre as BAL há um grupo de bactérias lácticas que não fazem parte da cultura láctica (non starter lactic acid bacteria - NSLAB), que são oriundas do leite cru, do ambiente de ordenha ou da indústria formando biofilmes. As NSLAB são representadas por espécies heterofermentativas de lactobacilos mesofílicos como Lactobacillus casei spp., L. paracasei spp., L. rhamnosus spp. e L. plantarum spp., e ainda por Pediococcus spp., Leuconostoc spp. e Micrococcus spp. NSLAB termoduricas como Bacillus spp. também são relatadas. As NSLAB em queijos podem ajudar a desenvolver sabor e aroma, porém também são associadas aos defeitos em queijos e leites fermentados. Problemas como odores estranhos, sabor amargo ou muito ácido, perda de viscosidade, perda de coloração, estufamento e formação de gás são associados com a presença e contaminação por NSLAB. Assim, as BAL são importantes micro-organismos na indústria láctea, garantindo sabores e aromas aos derivados. Já a presença de NSLAB podem ser associados com defeitos em queijos e leites fermentados, sendo um problema na indústria beneficiadora.   Palavras-chave: Característica Sensorial. Leites Fermentados. Queijo. Textura.                       Abstract Fermented dairy products contain acid bacteria (BAL) naturally present or added to the dairy matrix as starter cultures (starters), contributing to aroma, texture, nutritional value and microbiological safety. Lactobacillus spp., Streptococcus spp., Lactococcus spp. and Leuconostoc spp. are used as starter dairy crops. As BAL it can be classified as mesophilic (ex: Lactococcus lactis) and thermophilic (ex: Streptococcus thermophilus), and agree with its fermentation metabolites in homofermentative (lactic acid) and heterofermentative (lactic acid, carbon dioxide, diacetyl and other flavorings). Among the BAL, there is a group of lactic bacteria that are not part of the dairy culture (non-initiating lactic acid bacteria - NSLAB) that originate from raw milk, the milking environment or the biofilm-forming industry. NSLAB is represented by heterofermentative species of mesophilic lactobacilli such as Lactobacillus casei spp., L. paracasei spp., L. rhamnosus spp. and L. plantarum spp., and also by Pediococcus spp., Leuconostoc spp. and Micrococcus spp. Termoduric NSLAB such as Bacillus spp. are also related. NSLAB in cheeses may help develop flavor and aroma, and they are also associated with defects in fermented cheeses and milks. Problems such as strange odors, bitter or very acidic taste, loss of viscosity, loss of color, establishment and gas training are associated with the presence and contamination by NSLAB. Thus,  BALs are important microorganisms in the dairy industry, contributing to the dairy flavors and aromas. The presence of NSLAB, on the other hand, can be associated with defects in fermented milk and cheese, being a problem in the processing industry.   Keywords: Cheese. Fermented Milk. Sensory Characteristic. Texture.


2020 ◽  
Vol 47 (2) ◽  
pp. 119-129
Author(s):  
Mirjana Grujović ◽  
Katarina Mladenović ◽  
Ljiljana Čomić

In this paper, the effect of different temperatures, pH, and NaCl concentration on the growth of autochthonous lactic acid bacteria isolated from traditionally made Serbian cheese (Sokobanja area) was investigated by using the spectrophotometric method. Growth of tested Lactobacillus (Lb. fermentum, Lb. plantarum, and Lb. brevis) and Lactococcus lactis subsp. lactis biovar. diacetylactis five isolates were better in acidic pH, while the growth of Enterococcus isolates (E. durans, E. faecium, and E. faecalis) was better in basic pH, at 37 °C. At 4 °C after 24 h, none of the tested bacteria showed growth. Since the autochthonous isolates were tolerant to a tested range of dairy processing conditions, further studies need to include the characterization of enzymatic activity of selected isolates, as well as the ability to use these isolates like starter cultures or food supplements in dairy or non-dairy products.


2020 ◽  
Vol 44 (5) ◽  
pp. 523-537 ◽  
Author(s):  
Avery Roberts ◽  
Rodolphe Barrangou

ABSTRACT As a phenotypically and phylogenetically diverse group, lactic acid bacteria are found in a variety of natural environments and occupy important roles in medicine, biotechnology, food and agriculture. The widespread use of lactic acid bacteria across these industries fuels the need for new and functionally diverse strains that may be utilized as starter cultures or probiotics. Originally characterized in lactic acid bacteria, CRISPR-Cas systems and derived molecular machines can be used natively or exogenously to engineer new strains with enhanced functional attributes. Research on CRISPR-Cas biology and its applications has exploded over the past decade with studies spanning from the initial characterization of CRISPR-Cas immunity in Streptococcus thermophilus to the use of CRISPR-Cas for clinical gene therapies. Here, we discuss CRISPR-Cas classification, overview CRISPR biology and mechanism of action, and discuss current and future applications in lactic acid bacteria, opening new avenues for their industrial exploitation and manipulation of microbiomes.


2011 ◽  
Vol 361-363 ◽  
pp. 701-706 ◽  
Author(s):  
Hai Rui Zhai ◽  
Han Lin Zhou ◽  
Jin Song Yang ◽  
Qian Wang ◽  
Hai Sheng Tan ◽  
...  

Four lactic acid bacteria (LAB) strains named HN78, HN87, HN91 and HN113 were separated fromStylosanthes guianensis SW. of Hainan province, which were identified bacterially using the classical classification and the sequences of 16S rDNA. The results showed that four strains wereEnterococcus hirae,Enterococcus faecalis,Lactococcus lactisandLactobacillus plantarum. The capability of lactic acid production of HN113 and HN91 were better than HN78 and HN87.


2019 ◽  
Vol 12 (1) ◽  
pp. 54-69 ◽  
Author(s):  
É. Laslo ◽  
É. György ◽  
A. Czikó

Abstract Fermented meat products represent an important segment of our alimentation. Obtaining these products is based on beneficial microorganism activity. In the case of traditional food products, these are commercial starters or autochthonous microflora. Fermentation of raw materials is mainly done by sugar metabolization of lactic acid bacteria (LAB). In addition, these microorganisms can have other beneficial properties too such as probiotic properties, antimicrobial compound production abilities, etc. In order to meet consumer demands, starter cultures are continuously developed to produce high-quality, healthy, and tasty products, thus contributing to guaranteeing microbiological safety and to improving one or more sensory characteristics, technological, nutritional, or health properties of the fermented products. The aim of our research is to determine the technological properties of autochthonous lactic acid bacteria originated from commercial fresh sausages in order to select and use them as potential starter cultures in the meat industry. In our work, we determined the relevant characteristics (such as salt tolerance, proteolytic activity, antimicrobial activity, and antibiotic resistance) of bacteria isolated from 16 fresh sausages. Based on our results, the studied bacterial isolates originated from sausages could be potentially used as autochthonous meat starter cultures.


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