Biopreservatives (edited by Ayan Santra)

1. BIOPRESERVATIVES
SUBMITTED TO – DR. RANJEETA BHARI
SUBMITTED BY – ARSHDEEP KAUR
CLASS – MSC. BIOTECHNOLOGY (HONS.)
Semester - 3
ROLL NUMBER – 19011007

2. Biopreservatives
• Biologically derived antimicrobial substances which can be
used to preserve food and extending shelf life.
• It reduces the amount of chemical preservatives and
intensity of heat treatments which can negatively effect the
food quality.

3. Need of Biopreservation
• Many food borne pathogens are known to cause spoilage
in food.
• Some Gram positive bacteria such as S. aureus and B.
cereus are known to cause food intoxification in heated
and processed vegetables.
• Listeria monocytogenes (causes listeriosis - food borne
disease ) which multiplies at 3 degree temperature and
grow frequently in refrigerated and canned foods.

4. Properties of Biopreservatives
• Should not be toxic
• Acceptable by recognized authorities such as FDA
• Its use should be economical to industries
• Should be sufficiently stable

5. Classification of Biopreservatives
1 yeast as biopreservatives
2 microbial acids
3. Lacto-biopreservatives
4. Bacto-biopreservatives
5. Phyto-antimicrobial

7. 1.micobial ACID BIOPRESERVATIVES
• microbial acids are used to inhibit microbial growth by
lowering pH, affecting the proton gradient across biological
membrane and acidifying cytoplasm.
• Organic acids such as lactic acid, acetic acid and citric acid –
used in acid biopreservatives.
• These acids enhance the flavour of acidified or fermentive
foods such as cheese, pickles and sausages.

8. Lactic acid
• Lactic acid is a milk associated acid also known as 2-hydroxyl propionic
acid present in almost all life forms.
• Potassium and sodium lactate are widely used in food industry.
• Lactic acid bacteria including the genera lactobacillus, leuconostoc, and
Pediococcus have been used in fermentation to preserve the nutritive
qualities of various foods.
• It has capacity to reduce pH - sufficient to antagonize many
microorganisms
• The main application is in the decontamination of meat and poultry
carcasses.
• Acetic acid and propionic acids are also produced in small amount by
lactic acid bacteria which have same effect as lactic acid.

9. Acetic acid
• Naturally occurring (produced during fermentation) and relatively
inexpensive organic acid, which has been traditionally used as a
food preservative .
• Advantage - low cost, GRAS (generally recognized as safe) status
and low toxicity.
• Major disadvantage its acidic taste and strong sourness intensity.
• When acetic acid dissolves in solution, it releases free proton which
decreases pH. (increase number of protons on outer surface of
microorganisms - disrupt the membrane of microorganisms by
denaturing enzymes)

10. Applications of Acetic acid-
1. Decontamination of meat
2. Decontamination of poultry
3. Decontamination of sea food
4. Also imparts flavour so used in mayonnaise, salad dressing,
ketchups, sauces, pickles etc.

11. Citric acid
• Citric acid was initially produced from citrus fruits, but due
to increasing demand, Aspergillus niger is used for its
production.
• It possess antimicrobial activity by chelating metal ions.
• Citric acid was more inhibitory to thermophilic bacteria than
lactic acid and acetic acid.
• Citric acid also acts as buffering agent to maintain the pH
4.5 – 5.5.

12. 3. LACTO-BIOPRESERVATIVES
• Milk components such as lactoferrin, lactoperoxidase,
lactoglobulins and lactolipids are used as biopreservative.
LACTOFERRIN :
• LF is present in external secretions such as saliva, tears and
mucous secretions.
• LF elicits a variety of inhibitory effects against microorganisms
comprising stasis (growth inhibition), cidal (direct destruction),
adhesion, cationic and opsonic effect mechanisms.

14. 4. Bacto-biopreservatives
• bacterias are used as preservatives. bacteria are capable of
preventing the adherence, establishment, replication and
pathogenic action of specific enteropathogens.
• Bacto-biopreservatives actes by:
(a) decreasing the pH
(b) Rendering specific nutrients unavailable to pathogens
© decreasing the redox potential of environment
(d) Producing hydrogen peroxide
(e) Producing specific inhibitory substances such as bacteriocins.

15. BACTERIOCIN
• Proteinaceous or peptidic toxins produced my bacteria which
inhibit growth of similar or closely related strains
• Similar to yeast and paramesium killing factors
• Not much useful as food preservative – expensive, broken down in
food products, harm some proteins in food
• Active against E. coli, Salmonella
• Use of bacteriocin in food – generally regarded as safe by FDA
• Only two bacteriocins considered safe for use :
Nisin
Pediocin

16. NISIN:
• Nisin is the only bacteriocin, approved for use as an antimicrobial in
food by the Joint FAO/WHO Expert Committee on Food Additives
• Used in over 50 countries
• heat stable polypeptide produced by dairy organism Lactococcus lactics
• Effective in a number of food systems
• Wide range of inhibition spectrum
• The level of nisin used depends on:
 Food composition
 Required shelf life
 Temperatures likely to be encountered during storage

17. • Action of nisin against spores is sporicidal rather than
sporostatic and spores are more sensitive than cells.
• The flexible nature and amphiphilic properties of nisin
molecule are important for this character.
• Nisin inhibits NAG synthesis in Bacillus subtilis and DNA, RNA
and protein synthesis in M. luteus.

18. Pediocin
POTENTIAL BACTERIOCINS AS BIOPRESERVATIVES
• Most pediocins are:
• Thermostable proteins
• Active over a wide range of pH
• Produced by Pediococcus strains such as P. acedilactici
• Pediocin AcH:
• Active against both spoilage and pathogenic organisms
• L. monocytogenes, Enterococcus faecalis, Staphylococcus aureus and
Clostridium perfringens

19. MECHANISM OF ACTION
1. Antibacterial : against Gram positive bacteria, causes cell
death due to impairment of the cytoplasmic membrane of
sensitive bacteria resulting in the leakage of cellular ions
and small molecules and UV absorbing material.
 Spores are resistant to pediocin, however after the spores
germinate, they are killed by pediocin.
2. Bactericidal : treatment of Listeria strains with pediocin
caused rapid collapse of the membrane potential, resulting in
the death of cell.

20. 3. Lysis of sensitive cells: in some strains, activation of
autolytic enzymes causes the cells to lyse.
4. Immunity and resistance against pediocin: some species are
not sensitive to pediocin .
• Producer strain is not sensitive to its own pediocin.
• Lipopolysaccharide molecule of Gram negative bacteria are
resistant to pediocin.
APPLICATIONS:
Prevent food spoilage in ground beef, sausage mix, milk and ice
cream and extend the shelf life of macaroni salad and potato
salad.

21. 5. PHYTO-ANTIMICROBIAL
• The edible plants as well as their phytochemicals are used in food
preservation eg Spices and herbs
• The various phytochemicals which are used in biopreservation and
act as antimicrobials, are
i. Phytophenols
ii. Saponins
iii. Flavonoids
iv. Thiosulphinates
v. Catechins and agar.

22. i) PHYTOPHENOLS
• Mainly the phenolic compounds possess antimicrobial activity
such as cinnamon, allspice and clove buds.
• Oregano, savory and thyme demonstrated antifungal activity.
• The mode of action of phenolic compounds is generally
thought to involve interference with functions of the
cytoplasmic membrane including proton motive force and
active transport.
• This also changes the permeability of the membrane resulting
in possible leakage and affected the proton motive force.

23. iii) FLAVONOIDS
 Flavonoids are group of C15 aromatic compounds synthesized by a
confluence of the acetate/malonate and shikimate pathways.
 A single plant may contain different types of flavonoids such as
chalcones, dihydroflavones, flavones, anthocyanins and
proanthocyadin tannin.
 These flavonoids display antimicrobial property to penetrate
biological membranes.
 Isoflavonoids as potent fungal growth inhibitors could be extremely
useful in controlling plant diseases.

24. APPLICATION
 in PROCESSING of
 cheese
 Dairy dessert
 Milk
 Canned foods
 Cured meat
 Alcoholic beverages

25. References
• www.google.com