Biological and technological application of kefiran, an EPS from - - PowerPoint PPT Presentation

Biological and technological application

• f kefiran, an EPS from

kefir grains

Analía G Abraham Centro de Investigación y Desarrollo en Criotecnología de Alimentos

UNLP- CONICET. La Plata. Argentina

CIDCA

Kefiran

O H HO H HO H OH OH H H OH

O OH H H HO H OH OH H H OH

glucose galactose

Kooiman 1968, Micheli et al 1999

Non-digerible polysaccharide composed of glucose and galactose Produced by lactic acid bacteria (GRAS) included into kefir grains

Kefir grains Lactic acid bacteria (lactococcus, homo y hetero fermentatives lactobacillus) Yeast Acetic acid bacteria Kefir grains are natural immobilized starter consisting of a complex association of microorganisms Microorganisms are embedded in a proteins and polysaccharide matrix.

Kefir grains Incubation at 20 °C Milk or whey Filtration plastic sieve Fermented product grains

Kefir grains

Grain weight increases a function of subcultures

2 4 6 8 10 12 1 2 3 4 5 6 7 8 9 10 Subcultivos Peso (g) leche suero

Subcultures Milk Whey

Weight (g)

Protein Polysaccharide water LAB Yeast AAB Kefir grain composition Milk 5-6% 8-9% 86-87% Whey 6-8% 8-9% 83-84% 1.8 108 cfu/g 2.1 107 cfu/g 2.5 105 cfu/g

6.0 ± 0.05 dL/g

Kefiran: Physicochemical properties

7 8 9 10 Tiempo de retención

MW> 4 106 Molecular mass by gel permeation chromatography

Intrinsic Viscosity

• 100

1900 3900 5900 100 200 300 400 500 Velocidad de deformación (1/s)

Esfuerzo de corte (mPa)

0,3g/l 1,0g/l 2,0g/l 3,0g/l 6,0g/l

Shear rate (s-1) Shear stress (Pa)

Polysaccharides and

• ligosaccharides

Functional Aspects

• Prebiotic
• Non-digerible fibers
• Immune system stimulation
• Antiulcer
• Antitumoral

Polysaccharide and biological function

Dietary fibers FOSs GOSs inuline lactulose

Kefiran Effect of kefiran on cytopathic events triggered by Bacillus cereus on Caco 2 cells (In vitro study) Polysaccharide and biological function

• B. cereus: virulence factors

VEGETATIVES CELLS EXTRACELLULAR FACTORS

High haemolytic and citotoxic activity

Association to epithelial cells

Damages in enterocytes

Bacillus cereus on Caco 2: Caco 2 preincubated with kefiran Bacillus cereus on Caco 2 cells

Scanning electron microscopy

Control preincubation

• B. cereus

Kefiran antagonize cell death events triggered by B. cereus

Labelling of necrotic cells with Labelling of necrotic cells with Propidium Propidium iodide iodide

• B. cereus + kefiran

• B. cereus: virulence factors

VEGETATIVES CELLS EXTRACELLULAR FACTORS

High haemolytic and citotoxic activity

Association to epithelial cells

Damages in enterocytes

Without kefiran

Scanning electron microscopy Propidium iodide labelling

with kefiran Effect of Supernatant of Bacillus cereus on Caco 2 cells

*

In vivo studies: Balb C mice

Increment in mucus producing cells in small gut Increment in number of IgA producing cells in lamina propria

• ral

administration

• f kefiran

10 20 30 40 50 1

*

*

60 1 1 Number of globet cells

/10 vellosidades Control 2 días7 días

Control

7 days EPS

Control 2 days 7 days

8g% Fermented 250mg/L Grain

Kefiran

Kefiran as food additive

Does Kefiran improve texture

• f fermented food?

Technological application of kefiran

100 200 300 400 500 10 20 30 40 50 60

Viscosidad aparente a 300 seg-1 Kefiran (mg/L)

Rheological properties of glucono- δ-lactone induced skim milk gels

Kefiran (mg/L)

Apparent viscosity at 300 seg-1(mPa/s)

Kefiran improves texture

• f acid milk gels

Kefiran as food additive

Kefiran improves texture

• f fermented food

Technological application of kefiran : functional properties Gel forming ability

Kefiran cryogels :

Water holding capacity (WHC) 90.43 + 1.51%

Microscopic aspect of cryogels (magnification 200X)

Kefiran as food additive

Kefiran improves texture

• f fermented food

Technological application of kefiran : functional properties Gel forming ability Edible films formation

kefiran

Edible films formation

5g/l 7,5g/l 10g/l 57 cm2 Dry in oven at 50ºC

Films: Water vapour barrier properties

Films Films Water vapour Water vapour permeability permeability (WVP) (WVP) Chitosan Chitosan (10g/L) (10g/L) 9.03 9.03 × × 10 10-

• 11

11

Kefiran (10 g/L) Kefiran (10 g/L) 5.43 5.43 × × 10 10-

• 11

11

Cellophane Cellophane 8.4 8.4 × × 10 10-

• 11

11

LDPE LDPE 9.14 9.14 × × 10 10-

• 13

13

LDPE: low density polyethylene.

Perfiles de tracción

1 2 3 4 5 6 7 8 9 50 100 150 200 250 300 350 400 450 0g/l 1,25g/l 2,5g/l 3,75g/l

Elongation (%) Traction profiles

Films: mechanical properties

Tensile tests of films plasticized with glycerol

Texturometer Ta xT2i (TA.XT2i– Stable Micro Systems).

kefiran 1.25g/l Glycerol 2.5 g/l Glycerol 3.75 g/l Glycerol

Fermented product 8g% 250mg/L Grains

Kefiran

Frozen Kefir

Fermented milk Microorganisms with probiotic properties High inhibitory capacity of pathogens and contaminant microorganisms. Low lactose concentration (3.2%) Functional components Kefiran

Stability Crystal size Frozen kefir

30.3±1.8 99±41

Frozen kefir with cream

36.8±0.6 98±40

Frozen yogurt

18.8±1.1 87±28

Commercial ice cream

27.7±1.6 81±32 Frozen kefir without cream has higher stability than frozen yogurt and similar to commercial formulation

Kefiran

Frozen Kefir

10

5

10

6

10

7

25 12 CFU/ ml

Almacenamiento a-20 °C (dias))

Lactic Acid Bacteria Yeasts

Kefir helado

Non-trained sensorial panel High acceptability Kefir microflora maintains viable at least 12 days at –20°C

Frozen kefir

0 12 25 Storage at -20°C( days)

Fermented products Kefir grains Kefiran Development of novel functional foods Biological functionality Biological functionality Technological functionality Technological functionality

Judith Piermaria Micaela Medrano Fernanda Hamet Pablo Rimada Jessica Minnaard Silvia Racedo Ivanna Rolny Pablo Pérez Graciela Garrote Analia G Abraham Alejandra Londero Marina Golowczyc Pablo Mobili Emiliano Kakisu Martin Humen Fernando Trejo David Romanin Maria Serradell Graciela De Antoni

aga@biol.unlp.edu.ar

ANPCyT CONICET UNLP