food preservatives

Food Preservatives[FOOD PRESERVATIVES] April 12, 2012

[Type text]

Food Preservatives

Presented By:

Rahul Pancholi (09001012)

Shalinee Kavadiya (09001011)

[FOOD PRESERVATIVES] April 12, 2012

pg. 2

Table of Content

Introduction……………………………………………………………………………………………….….….…3 History of food preservatives………………………………………………………………………………3 Indian scenario of food processing…………………………………………………………………..…….3

Classification of Food Preservatives…………………………………………………………….……...4

Harmful effects of food preservatives………………………………………………………….………5

Sodium Benzoate…………………………………………………………………………………………….....…5

Sodium Nitrite………………………………………………………………………………………………..…….7

Citric Acid…………………………………………………………………………………………….……....………9

References…………………………………………………………………………………………………..………12

List of Figures

Figure 1: Production Flow Sheet of Sodium Benzoate………………...………….6

Figure 2: Production Flow Sheet of Sodium Nitrite……………………………….9

Figure 3: Production Flow Sheet of Citric Acid…………………………..………11

List of Tables

Table 1. Classification of Preservatives……………………………………………4

Table 2. Classification of Artificial Preservatives………………………………....4

Table 3. Free Benzoic Acid vs. pH……………………………….……………..…..5

Table 4. Permitted quantity of Sodium Nitrite and quality…………………..8

Appendix:

Table 6. Permitted Quantity of commonly used preservative……………………13


pg. 3

Introduction:

Other than shelter and clothing, food is the basic requirement of human beings to be alive.

Food is very necessary to keep our body working, to satisfy hunger and to get energy to do all

the activities.

Food is made and kept in specific conditions and climate by adding many chemicals to it. We

see that some fruits, vegetables come in specific season, like mango comes in summer

whereas custard apple comes in winter. If they are not kept in proper conditions chances of

getting spoiled increases. For example, if we keep bread out of refrigerator, after few days,

we see that it turns brownish black and smells very bad. When we keep any cooked vegetable

outside refrigerator for long time, it gets spoiled.

What are the reasons for all these?

This is mainly due to presence of bacteria, microorganism, insect, and enzymes etc, which get

environment (food, oxygen, moisture and suitable pH) to grow rapidly when food is not kept

under the specified required condition. Other reactions also may occur which cause food

spoiling. It accounts to the cost of food and health problem.

As population is growing very fast, demand of food is rising. We want food to be of good

quality and stay for long time. So to decrease the growth of microorganism, increase the shelf

life of food, making it available anytime anywhere with the same texture, color, smell, food

are preserve either by processing called food preservation or by adding chemical called food

preservatives.

Many food preservation processes are there to preserve food and increase shelf life, these are:

dehydration, salting, pickling, fermentation, drying, freezing, refrigeration, vacuum packing,

jellying etc.

History of food preservatives:

Before chemical preservatives came into picture, foods was kept in the container having water

so that the food remain cool and this work as refrigeration. Some food was placed in clay jars

to keep them away from air and moisture and hence prevent from spoiling. Salt was also a

famous preservative that time as it has desiccating effect, which draws water out of the food.

Modern method involves many other processes and man-made chemical for preservation of

food for long time. All these methods decrease the cost of the food and increase their shelf

life to a great extent.

Indian Scenario of Food Processing:

India is the world’s second largest producer of food next to China. Indian Food Processing

industry is ranked fifth in terms of production, consumption, export and expected growth. The

processed food market accounts for 32% of the total food market. According to the India

Food Report 2008 prepared by leading markets data provider Research and Markets, the

Indian food industry was estimated at over $182 billion, accounting for about two-thirds of

the country's total retail sector.

The turnover of the total food market is approximately Rs.250,000 crores out of which value-

added food products comprise Rs.80,000 crores. The Indian food processing industry is

primarily export orient. India's geographical situation gives it the unique advantage of

connectivity to Europe, the Middle East, Japan, Singapore, Thailand, Malaysia and Korea.


pg. 4

As the population is growing, food industry in India is rising and the investment in the food

industry is getting more and projected to grow by US$ 100 billion to US$ 300 billion by

2015. Another reason for preservation is long gap between production and actual

consumption of food products.

Classification of food preservatives:

Class-I preservatives (Natural

Preservatives)

Class-II preservatives (Artificial

Preservatives)

Naturally occurring substances, generally used

in kitchen Man-made chemical substance

No restriction or limitation on use as naturally

occurring Used in limited quantity

No need to be cautious in using them, so better

to choose product containing these type of

preservatives Risk in use as they are chemicals

Salt, Sugar, Vinegar, Alcohol Benzoic acid, sulfite, sorbate

Table 1. Classification of Preservatives

Preservatives Antimicrobial agents Antioxidant Chelating agent

Definition

Preserve food by preventing

the growth of microorganism

such as fungi, bacteria,

molds, yeasts

Preserve food by inhibiting

atmospheric oxidation and

prevent it from breakdown and

becoming rancid. Mainly used

with the products that contains

unsaturated fatty acids, oils and

lipids

Prevents the natural ripening

process & oxidative

deterioration of food by

inhibiting the bacteria;

parasite, fungi etc. prevent

food from becoming brown.

Mechanism

Reduces moisture content

and increases acidity which

creates the bad environment

for the growth of

microorganism. They retain

the quality of food like color,

smell, texture, nutrients etc.

In mechanism, free radical

initiates peroxide formation at

double bonds of fatty acid. The

chain reaction propagates to

other double bonds, and

aldehyde, ketone, and acid-

termination products thus create

the rancid off-flavors.

Same as antioxidants. They

are mixed with anti oxidants

to improve their

functionality by complexing

the metal ions that often

initiate free radical

formation and prevent metal

from oxidation

Examples

Banzoate (soft drinks, fruit

juices, beverages, baked

food), Sorbate (dairy

product, fermented

vegetables, confection,

smoked meat and fish,

beverages), Propionate

(cheese and baked food),

Nitrites (meat product)

Butylated hydroxyanisole,

BHA (butter, lard, meats, beer,

baked goods, snacks, potato

chips, nut products, dry mix for

beverages), butylated

hydroxytoluene, BHT (fats,

oils), Sulfites (beer, wines, dried

foods), Vitamin E (fruits and

vegetables).

Citric acid (foods,

beverages, dairy products,

pharmaceuticals), EDTA

(food processing),

Polyphosphates (fresh-

peeled fruits and vegetables)

Table 2. Classification of Artificial Preservatives

Choice of preservatives depends on many factor, like food product that has to be preserved,

climate and conditions, types of spoilage organism endemic to it, period of shelf life, ease of

applications, time lag between production and consumption of food product, cost etc.


pg. 5

No single preservatives satisfy all the conditions, so combination of many preservatives is

used.

Harmful effects of food preservatives:

Taking large quantity of preservative is also harmful leading to health problem.

People who are sensitive to small amount of particular preservative should not the

same.

Research published in the "Journal of the Egyptian Public Health Association" in

2001 discovered that intake of foods preserved with sodium benzoate and sodium

nitrite among pregnant rats is associated with a higher death rate in offspring. The

results suggest that pregnant women should need caution or avoid the consumption of

foods containing these preservatives.

Preservatives such as EDTA and Nitrites increase the risk of cancer.

Sulfite preservatives may cause asthma symptoms. Nowadays FDA prohibited the

use of sulfites preservatives as it causes respiratory diseases.

According to a 2007 study published in the journal "Lancet." Use of sodium benzoate

causes hyperactivity in children’s.

A number of food preservatives are banned because of severe health problems

associated with them.

Alzheimer's disease, an irreversible neurological disease that causes cognitive

deterioration and metabolic diseases is caused due to excess consumption of

preservatives.

Sodium Benzoate – Antimicrobial Agent

Properties- White powder, transparent in color in conformity with

ragulations

Purity standard- ≥99.0 and ≤100.5%, halogenide % FeCl3 ≤ 0.02, Heavy Metal

Pb % ≤ 0.001, loss on drying (%)≤ 2.0

Solubility in water- Highly soluble (61.2 gm. dissolve in 100 gm. at 25 °C)

Permitted Quantity- 0.1 % by weight (FDA standard)

Method of Production:

Sodium benzoate is produced by the neutralization of benzoic acid with caustic soda. The

resulting solution then treated to remove trace impurities as well as color bodies and then

dried in steam heated double drum dryers. The product removed from dryers is light and

fluffy and in order to reduce shipping and storage space the sodium benzoate is normally

compacted. It is then milled and classified into two product forms

1. Dense granular

2. Dense powder

It is also available in extruded form. This form is totally dust free. It dissolves more quickly

than the dense granular form in both water and antifreeze.


pg. 6

Process Flow Sheet:

Raw materials - Toluene and air

Figure 1: Production Flow Sheet of Sodium Benzoate

Conditions of reaction- Reactor Pressure- 200- 700 kPa

Reactor Temperature- 136-160 °C

Cobalt catalyst concentration- 25- 1000 ppm

Reactor benzoic acid concentration- 10- 60 wt %

Major Reaction:

C6H5COOH + NaOH NaC6H5CO2 + H2O

Used as preservatives in – Sauces, Pickles, cider, fruit juices, wine coolers, syrups and

concentrates, mincemeat and other acidic pie fillings, margarine, egg powder, fish, bottled

carbonated beverages, fruits preservation, jams, and jellies.

Sodium benzoate sensitivity- Persons who have experienced hypersensitivity reactions

(atopic allergy), respiratory tract symptoms including asthma, or skin reactions such as hives

and eczema, may be particularly vulnerable to benzoate sensitivity. This chemical can

damage mitochondria in cells, which leads to neuro-degenerative diseases

The following symptoms have been linked to ingesting foods with sodium benzoate:

Asthma, Urticarial (hives) and angioedema (tissue swelling), Rhinitis (nasal congestion due to

hay fever), Atopic and contact dermatitis, cutaneous vasculitis, Anaphylaxis


pg. 7

Note- Benzoate ion has essentially no antimicrobial properties; it is due to undissociated

benzoic acid that provides the antimicrobial action.

pH Free Benzoic acid (%) pH

Free Benzoic acid (%)

2.5 98 4.5 32.9

3 93.9 5 13.4

3.5 83 5.5 4.7

4 60.8 6 1.5

4.19 50 6.5 0.15

Table 3. Free Benzoic Acid vs. pH

Consumption in emerging market-

Price - US $ 1,340 - 1,355 / Ton

Sodium Benzoate pricing is driven by pricing of its core components: sodium hydroxide and

benzoic acid. The recent flurry of domestic and global natural disasters has had a significant

impact on supply and demand for sodium hydroxide, driving prices to higher than average

levels. During 2006-2009, world capacity for benzoic acid grew very high. In 2009,

beverages and food accounted for nearly 43% of the world consumption of benzoic

acid in the form of sodium and potassium benzoate, this is mainly due to it’s use in

preservation of food products. This compustions is froeast to grow at an average

annual rate of about 3% during 2009-2014.

Storage of sodium benzoate- Slightly hygroscopic and should be stored in sealed containers.

Exposure to conditions of high humidity and elevated

temperatures should be avoided.

Effective - Sodium benzoate is most effective below pH 4.5. Lower

pH level is required.

Sodium Nitrite (NaNO2) Antimicrobial Agent

Properties- stable, odorless, pale yellow or straw-colored compound, toxic,

Hygroscopic

Functions- Oxidizing agent hence acts as corrosion inhibitor but becomes

reducing agent to more powerful oxidizer such as KMnO4, K2Cr2O7, on acidification

produces nitrous acid which is unstable

Price- US $ 500 - 530 / Metric Ton

Specifications- 98.5% purity, powder, white fine crystal

Solubility- Soluble in water but has limited solubility in organic solvent

Relative Density- 2.168

Storage- Ventilated and dry place against rain heated and isolated under

sunlight.


pg. 8

Packing- Dry product- packed into 22.7 kg or 45.4 kg paper bags, which contain

polyethylene moisture barrier.

Liquid product- 40-42 % NaNO2 and packed in tank cars and tank

trucks

Incompatibility- Incompatible with ammonium salts, thiocyanates, thiosulfates and

strong reducing agents, should be kept away from them.

Toxicity- Toxic in high amounts for animals and humans. To prevent toxicity,

sodium nitrite is sold as a food additive is dyed bright pink to avoid

mistaking it for plain salt or sugar.

Level of sodium nitrite in vegetables is generally in range of 1.1 to 57 mg/kg.

Permitted quantity- Human body (0.07 mg of nitrite / kg of body weight per day),

Cauliflower (3.49 mg/kg), Fresh meat (0.4-0.5 mg/kg)

Uses- Formation of dye, rubber chemicals. Most of the uses are because of

oxidizing properties. It is used in metal finishing, meat curing. It is used

as corrosion inhibitor.

Disease caused - Cancer -nitrites can cause some forms of cancer. When proteins break

down, they form a chemical known as amines. When amines and

nitrites come into contact with each other, they form nitrosamines.

These chemicals are linked to an increased risk for colorectal cancer.

Those people who eat a lot of lettuce and those who have a high rate of conversion of nitrate

to nitrite are potentially most at risk to health damage from nitrate

Permitted Quantity of Sodium Nitrite:

Table 4. Permitted quantity of Sodium Nitrite and quality


pg. 9

Method of production:

1. Reduction of sodium Nitrate

2. Absorption of Nitrogen oxide into aqueous solution of caustic soda or soda ash

(industrial process)

Raw Materials: Ammonia, Air, Caustic soda or soda ash.

Reaction Involving:

4NH3 + 5O2 4NO + 6H2O

NO + Na2CO3 Na2NO2 +CO2

Process Description:

Liquid ammonia is oxidized by catalytic air oxidation at a high temperature in catalytic bed,

which forms nitrogen oxides (NOx).

The stream is sent to the absorption tower and gets contacted with alkaline solution (soda ash

or caustic soda). Low temperature and high pressure are required for the absorption to convert

NOx completely into Sodium nitrite and thereby minimizing the formation of sodium nitrate.

If caustic soda is used, the liquid from the absorption tower is sufficiently concentrated and

pure that can be sold directly but if soda ash is used, liquid is highly diluted, thereby water

should be removed before selling.

Then the slurry is sent to evaporator where it is concentrated and sent to crystallizer. Sodium

nitrite crystals form there and sent centrifuged to get pure crystal. Mother liquor is recycled

back to the stream going into the evaporator.

Since sodium nitrite is corrosion inhibitor, so equipments can be of mild steel. Crystals from

centrifuge are treated with anticracking agent to make them free flowing.

Uses: formation of dye, rubber chemicals. Most of the uses are because of oxidizing

properties. It is used in metal finishing, meat curing. It is used as corrosion inhibitor.

Process Flow sheet of sodium nitrite production-

Figure 2: Production Flow Sheet of Sodium Nitrite


pg. 10

Citric Acid -Flavor ingredient (chelating agent), pesticide and fungicide

Price - US $ 900 - 980 / Metric Ton

Specifications of citric acid - Purity 99.5% minimum, white crystal, 8-100mesh

Functions- oxidizing agent, chelating agent or added to antioxidants

to improve their functionality.

Solubility- water-soluble organic solid (576–771 g/l at 20 °C)

Relative Density- 1.665 at 20 °C

Storage of citric acid - Kept in lightproof. Well-closed, dry and cool place

Production- 879,000 MT in 1998 (worldwide)

CAS Registry Number- [77-92-9] – Anhydrous

Toxicity for rats- 1200 mg/kg/d. (experiment was performed on rats)

Disease caused- Irritation in eyes, in the respiratory pathways and on skin

World demand- Soft drinks and beverages account for more than half of the

world demand for citric acid.

Uses- citric acid is used mainly in food industry as preservatives, in jam, jellies and

candy to suppress the inversion of sucrose and adjust the pH, In salads and meat to prevent

enzymatic browning, in frozen food, fats and oils as chelating agent to inhibit metal-catalyzed

oxidation, in confections and desserts to enhance flavor and optimize gel-setting

characteristic, in dairy products to decrease the viscosity of the mix to make it easy to whip.

Citric acid forms complex with many multivalent ions to form chelate as it has ligancy more

than one. So, it control metal contamination and prevent metal to undergo any reactions. It

does not affect color, stability, and texture of food product.

Method of production:

Raw material: Molasses, sucrose, and dextrose, calcium hydroxide, sulfuric acid

Process Description: (by fermentation of Aspergillus niger microorganism) There are two

processes:

1. Surface Fermentation

2. Submerged Fermentation.

Submerged process is preferred nowadays as it requires less space, less time, it is less labor

intensive and yield is more. This process is used for large volume industrial production.

Aspergillus Niger molds is grown under specific conditions (of pH, nutrients). Sterile air is

sparged into the fermentor where sugar is converted to citric acid. The process of

fermentation is very long and takes 7-8 days.


pg. 11

From fermentation broth, citric acid is separated using filtration and purified by lime sulfuric

extraction.

In lime sulfuric process, calcium hydroxide slurry is added to fermentation broth, which

precipitates calcium citrate.

After sufficient time, calcium slurry is filtered, filter cake is washed, reslurried and acidified

with sulfuric acid, which form citric acid and calcium sulfate.

Calcium sulfate is insoluble which then removed. Final solution of citric acid is then

deionized to remove trace of calcium, decolorized and other processes are taking place to

improve crystallization.

Aqueous solution of citric acid is then sent to evaporator followed by crystallizer. Crystals of

citric acid forms which are then washed, dried the packed for selling. As aqueous solution of

citric acid is mildly corrosive equipments are made by316 stainless steels

Another process also can be used to recover citric acid from fermentation broth is liquid

extraction. Where hydrocarbon is used as solvent for recovery.

Process Flow sheet of citric acid production-

Figure 3: Production Flow Sheet of Citric Acid

Consumption in world market-

International India

Food, beverages & confectionery 70% 40%

Pharmaceuticals 12% 55%

Industrial application 18% 5%

Table 5. Consumption of Citric Acid

There is a scope of growth in industrial sector in India since we are lagging from international

economy.


pg. 12

References-

1. Kirk-Othmer Encyclopedia of Chemical Technology, Volume-3, 6, 12, 22

2. Sodium Nitrite from China and Germany, Investigation Nos. 701-TA-453

(Final) and 731-TA-1136-1137 (Final) 3. http://www.livestrong.com/article/288335-the-most-common-food-

preservatives/

4. 03_Organic_acids_Mattanovich_1103.pdf

5. Livestrong website article number 467268

http://www.livestrong.com/article/467268-food-preservatives-disease/

6. Dsir government report on citric acid

http://www.dsir.gov.in/reports/techreps/tsr032.pdf

7. http://chemical.ihs.com/nl/Public/2010/1006/1006.html#a=

8. http://www.shreeadditives.com/htmlsite/5a.htm

9. http://www.ihs.com/products/chemical/planning/ceh/benzoic-acid.aspx

10. New Perspectives for Citric Acid Production and Application, Carlos R.

Soccol, Luciana P. S. Vandenberghe, Cristine Rodrigues, and Ashok Pandey,

Bioprocess Engineering and Biotechnology Division, Department of Chemical

Engineering, Federal University of Paraná, Curitiba-PR, Brazil, and Ashok

Pandey, Biotechnology Division, Regional Research Laboratory, CSIR,

Trivandrum 695 019, India

11. http://www.inchem.org/documents/cicads/cicads/cicad26.htm#SubSectionNumber:11.1.1


pg. 13

Appendix 1 :

Permitted Quantity of commonly used preservative:

Preservatives

Acceptable Daily intake

(mg/Kg body weight) Commonly used levels (%)

Lactic Acid No limit No limit

Citric acid No limit No limit

Acetic acid No limit No limit

Sodium Diacetate 15 0.3-0.5

Sodium benzoate 5 0.03-0.2

Sodium propionate 10 0.1-0.3

Potassium sorbate 25 0.05-0.2

Methyl paraben 10 0.05-0.1

Sodium nitrite 0.2 0.01-0.02

Sulphur dioxide 0.7 0.005-0.2

Table 6. Permitted Quantity of commonly used preservative

Source FDA, 1991

food preservatives

Documents

production flow sheet

process flow sheet

total food market

free benzoic acid

citric acid production

benzoic acid

citric acid

shelf life