scholarly journals Effect of repeat unit structure and molecular mass of lactic acid bacteria hetero-exopolysaccharides on binding to milk proteins

2017 ◽  
Vol 177 ◽  
pp. 406-414 ◽  
Author(s):  
Johnny Birch ◽  
Hörður Kári Harðarson ◽  
Sanaullah Khan ◽  
Marie-Rose Van Calsteren ◽  
Richard Ipsen ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Molecular Mass ◽  
Repeat Unit ◽  
Milk Proteins ◽  
Unit Structure

scholarly journals Co-Microencapsulated Black Rice Anthocyanins and Lactic Acid Bacteria: Evidence on Powders Profile and In Vitro Digestion

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2579
Author(s):  
Carmen-Alina Bolea ◽  
Mihaela Cotârleț ◽  
Elena Enachi ◽  
Vasilica Barbu ◽  
Nicoleta Stănciuc
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Oryza Sativa L ◽  
Milk Proteins ◽  
Ethanolic Extract ◽  
Dry Weight ◽  
Hot Water ◽  
Raw Material ◽  
Black Rice

Two multi-functional powders, in terms of anthocyanins from black rice (Oryza sativa L.) and lactic acid bacteria (Lactobacillus paracasei, L. casei 431®) were obtained through co-microencapsulation into a biopolymer matrix composed of milk proteins and inulin. Two extracts were obtained using black rice flour as a raw material and hot water and ethanol as solvents. Both powders (called P1 for aqueous extract and P2 for ethanolic extract) proved to be rich sources of valuable bioactives, with microencapsulation efficiency up to 80%, both for anthocyanins and lactic acid bacteria. A higher content of anthocyanins was found in P1, of 102.91 ± 1.83 mg cyanindin-3-O-glucoside (C3G)/g dry weight (DW) when compared with only 27.60 ± 17.36 mg C3G/g DW in P2. The morphological analysis revealed the presence of large, thin, and fragile structures, with different sizes. A different pattern of gastric digestion was observed, with a highly protective effect of the matrix in P1 and a maximum decrease in anthocyanins of approximatively 44% in P2. In intestinal juice, the anthocyanins decreased significantly in P2, reaching a maximum of 97% at the end of digestion; whereas in P1, more than 45% from the initial anthocyanins content remained in the microparticles. Overall, the short-term storage stability test revealed a release of bioactive from P2 and a decrease in P1. The viable cells of lactic acid bacteria after 21 days of storage reached 7 log colony forming units (CFU)/g DW.

scholarly journals Degradation of Exopolysaccharides from Lactic Acid Bacteria by Thermal, Chemical, Enzymatic and Ultrasound Stresses

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 396
Author(s):  
Carsten Nachtigall ◽  
Harald Rohm ◽  
Doris Jaros
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Molecular Mass ◽  
Streptococcus Thermophilus ◽  
Structural Heterogeneity ◽  
Chain Scission ◽  
Simultaneous Application ◽  
Excessive Heat ◽  
Mass Distributions ◽  
External Stresses

During isolation, exopolysaccharides (EPS) from lactic acid bacteria are subject of thermal, chemical, enzymatic or ultrasound stress of different intensity that may affect macromolecular properties, for instance molecular mass or (intrinsic) viscosity. These parameters are, however, crucial, as they are associated with the technofunctional potential of EPS replacing commercial thickeners in nonfermented products. The aim of this study was to systematically examine treatments EPS are usually exposed to during isolation and to investigate the underlying degradation mechanisms. Solutions (1.0 g/L) of EPS from Streptococcus thermophilus, isolated as gently as possible, and commercial dextran were analyzed for molecular mass distributions as representative measure of molecule alterations. Generally, acid, excessive heat and ultrasonication, intensified by simultaneous application, showed EPS degradation effects. Thus, recommendations are given for isolation protocols. Ultrasonic degradation at 114 W/cm² fitted into the random chain scission model and followed third- (S. thermophilus EPS) or second-order kinetics (dextran). The degradation rate constant reflects the sensitivity to external stresses and was DGCC7710 EPS > DGCC7919 EPS > dextran > ST143 EPS. Due to their exceptional structural heterogeneity, the differences could not be linked to individual features. The resulting molecular mass showed good correlation (r² = 0.99) with dynamic viscosity.

scholarly journals Structure-Function Relationships of Glucansucrase and Fructansucrase Enzymes from Lactic Acid Bacteria

2006 ◽  
Vol 70 (1) ◽  
pp. 157-176 ◽  
Author(s):  
Sacha A. F. T. van Hijum ◽  
Slavko Kralj ◽  
Lukasz K. Ozimek ◽  
Lubbert Dijkhuizen ◽  
Ineke G. H. van Geel-Schutten
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Molecular Mass ◽  
Catalytic Domain ◽  
Structural Information ◽  
Protein Structures ◽  
Three Dimensional ◽  
Structural Features ◽  
Product Specificity ◽  
Gram Positive Bacteria

SUMMARY Lactic acid bacteria (LAB) employ sucrase-type enzymes to convert sucrose into homopolysaccharides consisting of either glucosyl units (glucans) or fructosyl units (fructans). The enzymes involved are labeled glucansucrases (GS) and fructansucrases (FS), respectively. The available molecular, biochemical, and structural information on sucrase genes and enzymes from various LAB and their fructan and α-glucan products is reviewed. The GS and FS enzymes are both glycoside hydrolase enzymes that act on the same substrate (sucrose) and catalyze (retaining) transglycosylation reactions that result in polysaccharide formation, but they possess completely different protein structures. GS enzymes (family GH70) are large multidomain proteins that occur exclusively in LAB. Their catalytic domain displays clear secondary-structure similarity with α-amylase enzymes (family GH13), with a predicted permuted (β/α)8 barrel structure for which detailed structural and mechanistic information is available. Emphasis now is on identification of residues and regions important for GS enzyme activity and product specificity (synthesis of α-glucans differing in glycosidic linkage type, degree and type of branching, glucan molecular mass, and solubility). FS enzymes (family GH68) occur in both gram-negative and gram-positive bacteria and synthesize β-fructan polymers with either β-(2→6) (inulin) or β-(2→1) (levan) glycosidic bonds. Recently, the first high-resolution three-dimensional structures have become available for FS (levansucrase) proteins, revealing a rare five-bladed β-propeller structure with a deep, negatively charged central pocket. Although these structures have provided detailed mechanistic insights, the structural features in FS enzymes dictating the synthesis of either β-(2→6) or β-(2→1) linkages, degree and type of branching, and fructan molecular mass remain to be identified.

Effect of Exopolysaccharide Producing Lactic Acid Bacterial on the Gelation and Texture Properties of Yogurt

2012 ◽  
Vol 430-432 ◽  
pp. 890-893 ◽  
Author(s):  
Shuang Zhang ◽  
Lan Wei Zhang
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Milk Proteins ◽  
Major Effect ◽  
Rheological Parameters ◽  
Production Structure ◽  
Texture Properties ◽  
Metabolic Properties

Lactic acid bacterial play a important role in yogurt texture and gel quality. The performance of lactic acid bacteria starter directly affected the quality of yogurt. Exopolysaccharide (EPS)-producing LAB may improve the texture of fermented milks, depending on the strain. EPS production was found to have a major effect on the texture properties and gelation properties, but varying textures with EPS production, structure and interaction with milk proteins. Yoghurts fermented with EPS-producing cultures showed different mouth thickness and ropiness rheological parameters and varying syneresis and gel firmness. The mechanism that how the metabolic properties of EPS producing lactic acid bacteria affect the texture and gel quality of yogurt is reviewed in the article.

Detection and characterization of a bacteriocin produced by Lactobacillus plantarum C19

1993 ◽  
Vol 39 (12) ◽  
pp. 1173-1179 ◽  
Author(s):  
A. Atrih ◽  
N. Rekhif ◽  
J. B. Milliere ◽  
G. Lefebvre
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Molecular Mass ◽  
Key Words ◽  
Lactobacillus Plantarum ◽  
Resistant Bacteria ◽  
Acidic Ph ◽  
Gram Positive Bacteria ◽  
Ph Dependent

Strain C19, isolated from fermented cucumbers and identified as Lactobacillus plantarum, produced a bacteriocin. This bacteriocin, named plantaricin C19, was stable at acidic pH, was relatively thermostable, and had a molecular mass of about 3.5 kDa. It inhibited some pathogenic (i.e., Listeria spp.) and spoilage Gram-positive bacteria but had weak or no action against lactic acid bacteria. Its adsorption on sensitive and resistant bacteria was pH dependent and was reduced by pretreatment of cells with lipase or lysozyme. Curing treatments with acriflavine or novobiocin yielded nonproducing mutants sensitive to plantaricin C19.Key words: lactic acid bacteria, Lactobacillus plantarum, bacteriocin, protein.

161. Studies in Cheddar cheese. VI. The degradation of milk proteins by lactic acid bacteria isolated from cheese, alone, with sterile rennet and with whole rennet

1937 ◽  
Vol 8 (2) ◽  
pp. 238-244 ◽  
Author(s):  
J. G. Davis ◽  
W. L. Davies ◽  
A. T. R. Mattick
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Amino Nitrogen ◽  
Milk Proteins ◽  
Cheddar Cheese ◽  
Protein Breakdown ◽  
Protein Nitrogen

It has been shown by experiments in milk that the enzymes of commercial rennet in conjunction with the lactic acid bacteria occurring in Cheddar cheese can bring about protein breakdown similar in extent to that found in the ripe cheese as far as the non-protein nitrogen is concerned. The amino nitrogen produced is, however, much less than in cheese. This may be ascribed to the higher pH of cheese as compared with that of the milk cultures, since acidity adversely affects the peptidases present. Attention is drawn to the differences between the conditions.

scholarly journals Bioprospecting for Bioactive Peptide Production by Lactic Acid Bacteria Isolated from Fermented Dairy Food

Fermentation ◽  
2019 ◽  
Vol 5 (4) ◽  
pp. 96 ◽  
Author(s):  
Davide Tagliazucchi ◽  
Serena Martini ◽  
Lisa Solieri
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Biological Activities ◽  
Milk Proteins ◽  
Fermented Food ◽  
Microbial Conversion ◽  
Dairy Food ◽  
Health Promoting ◽  
Sensorial Attributes ◽  
Fermented Dairy

With rapidly ageing populations, the world is experiencing unsustainable healthcare from chronic diseases such as metabolic, cardiovascular, neurodegenerative, and cancer disorders. Healthy diet and lifestyle might contribute to prevent these diseases and potentially enhance health outcomes in patients during and after therapy. Fermented dairy foods (FDFs) found their origin concurrently with human civilization for increasing milk shelf-life and enhancing sensorial attributes. Although the probiotic concept has been developed more recently, FDFs, such as milks and yoghurt, have been unconsciously associated with health-promoting effects since ancient times. These health benefits rely not only on the occurrence of fermentation-associated live microbes (mainly lactic acid bacteria; LAB), but also on the pro-health molecules (PHMs) mostly derived from microbial conversion of food compounds. Therefore, there is a renaissance of interest toward traditional fermented food as a reservoir of novel microbes producing PHMs, and “hyperfoods” can be tailored to deliver these healthy molecules to humans. In FDFs, the main PHMs are bioactive peptides (BPs) released from milk proteins by microbial proteolysis. BPs display a pattern of biofunctions such as anti-hypertensive, antioxidant, immuno-modulatory, and anti-microbial activities. Here, we summarized the BPs most frequently encountered in dairy food and their biological activities; we reviewed the main studies exploring the potential of dairy microbiota to release BPs; and delineated the main effectors of the proteolytic LAB systems responsible for BPs release.

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