Yeasts and the Fermented Food Renaissance

Graham H Fleet

Food Science

School of Chemical Engineering

UNSW Australia

Sydney

Australia, 2052

g.fleet@unsw.edu.au

Fermented foods and beverages—10,000 years ago!!

Microbial archeology

Fermented foods have natural origins and purpose

• Traditional processes that gave :

• preservation of foods with safety , sensory appeal, psychological enjoyment

• Scientific understanding gave :• industrialized, mass production,

starter cultures, commercial value

Bread, Cheese Yogurt, Beer ,

Wine etc

Traditional fermented foods

One Third !!!

Extensive field of research• Fermented Foods of the

World-- Campbell-Platt 1987

• Handbook of Food and Beverage Fermentation Technology--Liu et al 2004

• Handbook of Fermented Functional Foods--Farnworth 2008

• Fermented Foods and

Fermented foods--- since 1980s

Scientific understanding

• Fermented Foods and Beverages of the World--Tamang and Kailaspathy 2010

• Perspectives on Global Fermented Foods-- Soni and Dey 2014

• Oxford Handbook of Food Fermentations-- Bamforth and Ward 2014

Commercialization

New interest in fermented foods and beverages

McGee, H ( 2013) Nature, 504: 372-374 Despain, D ( 2014) Food Technology (Sept ) 39-45

A popular surge of interest

A popular surge of interest

Process advantages

Natural, healthy minimal process; not seen as processed foods; indigenous microorganisms; “ backslopping”, starter cultures

Ecologically sustainable

Products with regional character, diversity - added value

What is driving the fermented food renaissance ??

value

Process simply fine-tuned ( eg. temperature, strain) to give product diversity

Application to a diversity of raw materials– meats , cereals, fruits, vegetables

Western awareness of indigenous fermented foods in Africa , Asia, Central and South America

Health and well being benefits• Nutritional: enriched

proteins, vitamins; decreased anti-nutrients; increased bio-availability

What is driving the fermented food renaissance ??

HOW ??

Production of biogenic substances

: antioxidants, phenolics, bioactive

peptides, GABA, enzymes to degrade bio-availability

• Natural functional foods : diversity of positive impacts on gastrointestinal, cardiovascular, immune and central nervous systems

enzymes to degrade allergens, toxins

Impact on gut microbiota (microbiome)

Direct or indirect , new probiotics

The nutrition, health and gut microbiota linkage

Human diet

Gut

*Depression*Anxiety

*Cognitive function*Obesity*Type 2 Gut

microbiota

Health

*Type 2 diabetes*Immune function*Cancer

*Cholesterol*And so on

Ley R et al 2006. Human gut microbes associated with obesity. Nature 444, 1022

Clemente J et al 2012. The impact of the gut microbiota on human health; an integrative view. Cell 148, 1258

Kau A et al 2011. Human nutrition, the gut microbiome and the immune system. Nature 474, 327

David L et al 2014. Diet rapidly and reproducibly alters the human gut microbiome. Nature 505, 559

Cryan J and Dinan T 2012. Mind altering microorganisms: the impact of gut microbiota on brain and behaviour. Nature Reviews

The scientific evidence increases

of gut microbiota on brain and behaviour. Nature Reviews Neuroscience 13, 701

Derrie M at al 2015. Fate activity and impact of ingested bacteria within the human gut microbiota. Trends in Microbiology 23, 354

Lang J et al 2014. The microbes we eat--.PeerJ, 2:e569

Gobbetti M et al 2010. Functional microorganisms for functional food quality. Crit Rev Food Science and Nutrition 50, 716

Selhub E et al 2014. Fermented foods, microbiota and mental health: ancient practice meets nutritional psychiatry. J Physiological Anthropology 33, 2

Marsh A et al 2014 Fermented beverages with health promoting potential-. Trends in Food Science and Technology 38, 113

What about yeasts and fermented foods??

• Present in a diversity of other fermented foods, along with bacteria , filamentous fungi

• What is their contribution to product quality, functionality?

• What happens to yeasts during ingestion and digestion?ingestion and digestion?

• What is the occurrence and significance of yeasts in the human gut??

Bacterial bias !!

• Alcoholic fermentation-ethanol , flavour volatiles

• Hydrolysis of starch, protein, lipids, pectins

• Utilization of organic acids-citric, malic, lactic

• Degradation of anti-nutrients-phytic acid

• Enrichment of vitamins- folic acid, B vitamins

• Enrichment of antioxidants

• Autolytic products

Functional attributes of yeasts in fermented foods

• Autolytic products

• Stimulation of bacterial growth

• Inhibition of bacterial, fungal growth

• Adsorption, degradation of toxic substances,

• Probiotic effects

Moslehi-Jenabain, Pedersen, Jespersen. 2010. Nutrients 2: 449-473

Fermented milk products with high populations ( 106-108 cfu/g) of

yeasts- cheeses, kefir, koumiss, aryan, rob, amasi etc

Debaryomyces hansenii ; Yarrowia lipolytica; Kluyveromyces marxianus; Saccharomyces

cerevisiae

Saccharomyces cerevisiae, Kluyveromyces marxianus, Kazachstania unispora, Dekkera anomala, Issatchenkia

occidentalis; Torulaspora delbrueckii

Garofalo et al 2015 Food Microbiol 49:123Marsh et al 2013 FEMS Microbiol Let 348:79

Kefir: expanding market; diversity of milks; apply granules to fruit juices

Zeynep B et al 2011 Review: functional properties of kefir. Crit Rev Food Science and Nutrition, 51, 261

• Health beverage since 2000 years in China

• SCOBY-symbiotic culture of bacteria and yeast

• Slightly sweet, acidic ( acetic),mild ethanolic flavour

• Acetic, lactic, gluconic acids,

Kombucha—fermented tea ( tea fungus)

(nata de coco)

• Acetic, lactic, gluconic acids, pH 2-3

• Main bacteria: (acetic acid bacteria , lactic acid bacteria) Komagataeibacter xylinus ( Acetobacer xylinum), Gluconoacetobacter, Acetobacter, Lactobacillus, Lactococcus spp

Culture and culture independent studies

• Zygosaccharomyces ( Z. lentus, Z bisporus, Z bailii);

• Dekkera bruxellensis; D anomala

• Schizosaccharomyces

Kombucha yeasts

• Schizosaccharomycespombe

• Torulaspora delbrueckii

• ( 106-108 cfu/g)

• Teo et al 2004 Int J Food Microbiol.95, 119

• Marsh et al 2014 Food Microbiol.38,171

Yeasts 106-108 cfu/ml

• Saccharomyces cerevisiae

• Schizosaccharomyces pombe

• Saccharomycodes ludwidgii

• Zygosaccharomyces spp

Traditional alcoholic beverages: palm wines, fruit wines, beers—high populations of yeasts

Lactic acid bacteria, acetic acid bacteria, Zymomonas mobilis—106-109 cfu/ml

Microbiology of fruit wines

Some microorganisms of natural/indigenous fruit juice fermentations

• Pineapple : Pichia guilliermondii, Hanseniaspora uvarum, Lactobacillus plantarum ( di Cagno et al 2010; Chanprasartsuk et al 2010)Chanprasartsuk et al 2010)

• Gabiroba: Candida quercitrusa, Issatchenkiaterricola, Saccharomyces cerevisiae, lactic acid bacteria ( Duarte et al 2009)

• Masau: Issatchenkia orientalis, Pichiafabianii, Saccharomyces cerevisiae, Lactobacillus plantarum etc ( Nyanga et al 2007)

Growth of yeasts during indigenous pineapple juice fermentation ( Chanprasartsuk 2008 PhD Chulalongkorn Uni.)

Hanseniaspora uvarum ; Pichia guilliermondii, dominant yeasts ; absence of Saccharomyces cerevisiae

• Which microbial groups or species are important ??

• What is the strain influence??>

• Which ones are essential ??

• Which ones cause spoilage?

Untangling the complex ecology

Fermented Food

Yeasts Fungi

Bacteria

Bacteriophages

Microbial interactions

Wholistic, integrative approach

Raw materials Process of

Microbial

ecologyQualitative data

Quantitative dataPhysiology

BiochemistryGenomics

( strain level)

Properties

ChemicalPhysicalSensory Safety

Functional

Process of production

Product quality criteria

( strain level)

Analytical

toolsMicroscopy

CultureMolecular culture-

independentMALDI TOF

Analytical toolsGC/LC MS

NMRElectron

microscopy

PLANTATION

DRYING

Yeasts are essential for cocoa fermentation Ho et al 2014 Int J Food Microbiol. 174: 72-87

Yeasts: Hanseniaspora , Pichia, Saccharomyces,

Kluyveromyces spp

Lactic acid bacteria: Lactobacillus , Leuconostoc,

Lactococcus spp

Acetic acid bacteria:

FERMENTATION(3-6 DAYS)

HARVEST PODS

REMOVE BEANS AND PULP FROM

POD

Acetic acid bacteria: Acetobacter, Gluconobacter spp

Selective inhibition studies:

NatamycinNisin-Lysozyme

0

2

4

6

8

10

0 1 2 3 4 5 6

Log

10

(cf

u/g

be

an

)

Fermentation time (day)

The growth of bacteria during

spontaneous fermentation

Lactobacillus plantarum Lactobacillus fermentum

0

2

4

6

8

10

0 1 2 3 4 5 6

Log

10

(cf

u/g

be

an

)

Fermentation time (day)

The growth of bacteria during yeast-

inhibited fermentation

Lactobacillus plantarum Lactobacillus fermentum

Cocoa fermentation in presence of natamycin (no yeasts)

Lactobacillus plantarum Lactobacillus fermentum

Gluconobacter sp. Acetobacter pasteurianus

Lactobacillus plantarum Lactobacillus fermentum

Gluconobacter sp. Acetobacter pasteurianus

Cocoa beans fermented with and without yeasts

With yeasts Without yeasts

CUT TEST

* The beginnings to 1900s--- indigenous fermentations, wild largely uncontrolled

• * 1900 to 2000---controlled, single starter

The wine and beer stories continue

What next controlled, single starter culture fermentations, progressing to mixed starter cultures

• * 2000--- return to indigenous fermentations but controlled based on scientific understanding

What next ???

Unexpected consequences of yeast fermented food!!

Tape KetanIndonesia

Ardhana M and Fleet G. 1989. Int J Food Microbiol. 9: 157-165

Thank you

Food Microbiol. 9: 157-165

Fermented fruits

Fermented cereals- wheat , maize, sorghum, millet, rye, rice etc

Fermented legumes- soy beans, chick peas, lupins etc

Fermented vegetables

Fermented milks

The diversity of fermented foods

Moving outside the Fermented milks

Fermented meats, poultry, sea foods

Lactic acid fermentation, Alcoholic fermentation, Acetic acid/vinegar fermentation, Alkaline fermentation. OTHERS

outside the box

0

2

4

6

8

10

0 1 2 3 4 5 6

Log10 (cfu/g bean)

Fermentation time (day)

Total bacterial count during cocoa bean fermentation

Control Yeast inhibition

Cocoa fermentation in the absence of yeasts—no chocolate flavour !!

Control Yeast inhibition

0

2

4

6

8

10

0 1 2 3 4 5 6

Log

10

(cf

u/g

be

an

)

Fermentation time (day)

The growth of bacteria during

spontaneous fermentation

Lactobacillus plantarum Lactobacillus fermentum

Gluconobacter sp. Acetobacter pasteurianus

0

2

4

6

8

10

0 1 2 3 4 5 6

Log

10

(cf

u/g

be

an

)

Fermentation time (day)

The growth of bacteria during yeast-

inhibited fermentation

Lactobacillus plantarum Lactobacillus fermentum

Gluconobacter sp. Acetobacter pasteurianus

Hanseniaspora,

Kloeckera,

Candida,

Metschnikowia,

Pichia,

Yeasts and the alcoholic fermentation

4

6

8

Candida spp.

Saccharomyces cerevisiae

Ye

ast

co

un

t (L

og

10

ce

lls/m

l)

Kluyveromyces,

Saccharomyces

cerevisiae,

Saccharomyces

bayanus

Successional growth of species and strains- also for “starter”

fermentations

0

2

0 2 4 6 8 10

Fermentation time (days)

Kloeckera/Hanseniaspora sppYe

ast

co

un

t (L

og

No yeasts vs. no lactic acid bacteria