Direct and indirect benefits of biodiversity

 Environmental economics (or ecological economics) assigns economic values to species, communities and ecosystem. There can be Direct and indirect economic benefits of biodiversity

Direct benefits

Direct economic benefits or commodity values, are assigned to the products harvested by people.

Direct economic benefits of biodiversity 

A) Food supply Biodiversity provides high variety of food : crops , livestock , forestry, and fish are important food source of human species. However the number of species have been domesticated and cultivated are small if comparing with the number of species existing. 

According to the Food and Agricultural Organization of the United Nations, humans currently cultivate only 150 plant species, and just a few provide over half of the food we eat. Just 15 animal species make up over 90% of our livestock. 

Monocultures (large-scale cultivation of single varieties of single species) are extremely vulnerable to disease. A water mold caused the Irish potato famine where potatoes had been bred from a single Incan variety. 

Potential for hybridization requires a diverse “bank” of wild, native species. Contemporary breeders increase genetic diversity by hybridizing crop species with wild species adapted to local climate and disease.

The control/wild species can be used to protect the crop against pest and weeds . The economic loss due to the loss of crops/ food can be reduced with the use of the control species. 

 B) Clothing, shelter and other products As around 40,000 species of plants, animals, and fungi provides us with clothes, shelter, and other products like timber, skins and furs, fibers, fragrances , papers, silks, dyes, poisons, adhesives, rubber, resins and more. 

C) Medicine and medical models . According to American Museum of Natural History Centre for Biodiversity Conservation ; 57% of most important drugs come from nature, yet only a fraction of species with medicinal potential have been studied.  

The Rosy Periwinkle (A) is the source of two chemotherapy drugs effective against leukemias. The mold Penicillium (B) produces the antibiotic penicillin to inhibit competing microorganisms. Aspirin originates in the bark of the White Willow (C) several species of tropical frogs in the genus Phyllobates (D) produce poisons used by South American tribes for hunting with darts.

Unique features of certain species have opened windows into how life work. For example, the Atlantic squids giant axon revealed the basics of neurophysiology and the horseshoe crab's optic nerve and photoreceptors taught us how vision works. Animals also serves as disease models. For example, Armadillos suffer from leprosy and sea squirts from kidney stones. 

D) Biomimicry, also known as biomimetics or bionics, uses organisms for engineering inspiration and human innovation. Rattlesnake heat-sensing pits, for example, suggested infrared sensors. Zimbabwe’s Eastgate Centre  incorporates air-conditioning principles from termite mounds. The 2006 Mercedes-Benz Bionic employs the body shape of the yellow box fish to combine high internal volume and efficient aerodynamics. Only 10% of current technology employs the highly efficient biological designs crafted by evolution and natural selection. Loss of biodiversity is the loss of millions of years of evolutionary wisdom.

E) Energy We use animals for energy and transportation. And the biomass for heat and other fuels. Pack animal, domesticated animal that is used to carry freight , goods , or supplies. For example, donkey is the oldest known pack animal having been in use possibly as early as 3500 BC. Camel that are used in deserts , horses and mules that are used in mountainous terrain are also examples. Solid biomass such as wood and garbage can be burn directly to produce heat. Biomass can also be converted into a gas called biogas or into liquid biofuels. Hydroelectric power depends on ecosystem structure

F) Warnings to toxins and other ecosystem disruptions Certain species warn us of toxin in the environment . 'Ecosystem canaries’ can provide early warning signals of large , potentially catastrophic  changes or tippping points in ecosystem . Ecosystem canaries’ are species that are often the first to disappear from a stressed environment . Their vanishing can be linked to changes in the functioning of ecosystem , which can serve as a warning that a tipping point is approaching . For example, when the peregrine falcon nearly went extinction , it warned us of the  dangers of the pesticide DDT and food chain concentration of toxins.

 Indirect Benefits of Biodiversity 

Indirect benefits are provided by biodiversity that do not involve harvesting or destroying the natural resource. Such benefits include ecological benefits such as soil formation, nutrient cycling, waste disposal, air and water purification, education, recreation, future options for human beings, etc. 

Indirect Benefits can be further sub-divided as:

A) Increasing ecosystem productivity : Ecologist David Tilman compared grassland plots to show that increasing species diversity increased overall productivity (yield). Different plants utilize different resources, so a variety of plants may more completely use resources within an area. As noted above, diversity also reduces system vulnerability to pests and disease. 

B) Increasing ecosystem stability Tilman observed his grassland plots through several cycles of drought and documented a similar relationship between biodiversity and stability. Plots which were more diverse were more resistant to drought and later recovered more completely. Reducing ecosystem vulnerability to pests and disease may also be a factor in the relationship between diversity and stability. 

C) Maintaining the atmosphere Plants and algae produce the oxygen which makes up 20% of the atmosphere essential to aerobic organism, and remove carbon dioxide produced by respiration and burning fossil fuels. Oxygen is also critical to life because it helps to maintain the ozone shield , protecting life from dangerous Ultra- violet radiation. 

D) Maintaining soils Soil microorganisms maintain nutrients in complex but critical chemical pathways. Vegetation and litter prevent erosion of soils which require thousands of years to form. Estimates suggest that erosion destroys as many as 3 million hectares of cropland annually, and that as much as onefifth of the world’s cropland is “desertified” through salination, acidification, or compacting.Plants helps to prevent soil erosion. They also improve soil quality when they decompose. Microorganism purifies water in rivers and lakes. They also return nutrients to the soil. 

E) Maintaining water quality Water treatment plants rely in large part on microorganisms for water purification, and natural systems do the same. In nature, wetland, waterway, and watershed root systems combine with soil adsorption and filtration to accomplish water purification. When New York City decided to restore the Catskill watershed, their $1-1.5 billion investment in “natural capital” contrasted favorably with the $6-8 billion initial cost and $300 million annual operating cost of a new treatment plant. 

F) Fixing nitrogen One of the most amazing aspects of biological systems on earth is their absolute need for nitrogen – to build the proteins and nucleic acids upon which life depends – and their nearly universal dependence on microorganisms to “fix” atmospheric N2 gas and recycle the nitrogen of waste and death. Only after the bacterial “service” of processing nitrogen is it available in usable chemical form to plants, and through them, to animals. 

G) Nutrient recycling and waste disposal: Bacteria and nitrogen are not the only contributors to the waste management services of ecosystems. Fungi, protists, and scavengers help to decompose waste and dead organisms so that new life can reuse the available nutrients. 

H) Pest and disease control : According to the AMNH-CBC, farmers spend $25 billion annually on pesticides, while predators in natural ecosystems contribute 5 to 10 times that value in pest control. Costs associated with the use of chemical pesticides (such as water pollution) add to the value of natural pest control. Natural enemies are adapted to local environments and local pests, and do not threaten each other’s survival  as do broadspectrum chemical pesticides. Preservation of natural enemies is associated with preservation of plant diversity, as well. Disrupted ecosystems can lead to increasing problems with disease. In Africa, deforestation has led to erosion and flooding, with consequent increases in mosquitoes and malaria.

Monosodium glutamate (MSG)

 

Monosodium glutamate (MSG), a white crystalline substance is an important ingredient in the cuisines of China and Japan. MSG was first identified as a flavour enhancer in 1908 by Japanese chemist Ikeda Kikunae, who isolated it from seaweed kelp. In 1909 Saburosuke Suzuki, an entrepreneur, and Ikeda began the industrial production of monosodium L-glutamate (MSG) by extraction method in which vegetable proteins were treated with hydrochloric acid to disrupt peptide bonds.

Glutamate is a common amino acid that occurs naturally in a large range of foods including tomatoes, parmesan cheese, dried mushrooms, soy sauce, a host of fruits and vegetables, and human breast milk.  Monosodium glutamate (MSG)/monosodium L-glutamate or sodium glutamate, is the sodium salt of the amino acid glutamic acid.

MSG elicits a unique taste, known as umami, that is different from the other basic tastes (bitter, salty, sour, sweet). It enhances the complex flavours of meat, poultry, seafood, and vegetables. 

MSG-based condiment, Ajinomoto (‘essence of taste’) is now universally popular. MSG comes in many processed foods and snacks.  MSG does not occur naturally in whole foods. Manufacturers are required to state if MSG is included in products on their food content label. It might fall under different titles, including monopotassium glutamate and vegetable protein extract etc.

MSG ingested in large amounts may produce such physical reactions as burning sensations, facial tightness or pressure, and a tingling sensation in some individuals. These hypersensitive reactions, are known as MSG symptom complex—or, more informally, “Chinese restaurant syndrome”. Studies have shown no conclusive link between the syndrome and the consumption of normal levels of MSG, however.

Amino acids are usually produced by protein hydrolysis, chemical synthesis or microbiological (biotechnological) methods. The chemical synthesis of MSG can be carried out on a very large scale but it typically gives a racemic mixture of Land D-forms of amino acids. Extraction of amino acids from protein hydrolysate as a method of obtaining L-amino acids is not suitable for large-scale production of amino acids. Biotechnology methods (fermentation and enzymatic methods) have economic and ecological advantages. The enzymatic method has an advantage of producing optically pure amino acids in higher concentrations with less byproducts. In the industrial production of L-amino acids, the enzymatic method is not as popular as the fermentation method.

FERMENTATION METHOD

Fermentative production of amino acids was first reported by Kinoshita in 1957 where Corynebacterium glutamicum produced considerable amounts of L-glutamine from sugar and ammonia. It is now produced using a bacterial fermentation process with starch or molasses as carbon sources and ammonium salts as nitrogen sources.

The fermentation method is a production process in which a specific amino acid is synthesized in large amounts by a specially selected microorganism in culture. The selected microorganism is cultured with carbohydrates and ammonia and releases the L-form of the amino acid into the culture medium. The cell produces glutamate from 2-oxo-glutarate (2-oxo-pentanedioic acid) by reductive ammonia fixation that uses the enzyme glutamate dehydrogenase, a normal cellular constituent. Purification is by crystallisation and recrystallization of L-glutamic acid crystals  and subsequent conversion to MSG. The mother liquor of the crystallization process is then concentrated and used as a liquid fertilizer (after pH adjustment with ammonia).

The L-glutamate-producing bacterium was reported in 1957. Since then, many bacteria useful in glutamate production have been isolated, including Corynebacterium glutamicum, Brevibacterium lactofermentum, & Brevibacterium flavum. These glutamate-producing bacteria are all Coryneform bacteria, which are gram positive, nonspore-forming, and nonmotile and require biotin for growth.

Glutamate accumulation in the medium occurs only under biotin-limiting conditions. The requirement for biotin limitation prevented the use of standard raw materials such as sugar molasses because they contained biotin. The addition of a surfactant or of penicillin or the use of microorganisms auxotrophic for glycerol or oleate allowed the bacteria to produce large amounts of glutamate without biotin limitation.

The mechanism of excessive glutamate production by such microorganisms is still not understood. Under conditions in which glutamate accumulates in the medium there exists an active transport mechanism in glutamate producing cells that exports the amino acid into the medium. Identification of a glutamate export protein and its gene, yggB supports this mechanism.

 

                   

 

The fermentation method is applied for the industrial production of most L-amino acids, except for a few kinds of amino acids for which high production yields have not been achieved by fermentation. The economy of this method depends mainly on the cost of the carbon source, fermentation yield, purification yield, and productivity in the overall process.

Some problems in the fermentation processes can occur such as contamination of the culture with other microorganisms, bad fermentation reproducibility due to differences in the raw materials, back mutation or loss of genetic material in the production strain, infection of the culture etc.

Use of statistical software to analyze the results

Use of statistical software to analyze the results- SPSS

 “Statistics” is a “collection of numerical facts or data”. It is also a “body of methods and techniques for analyzing numerical data”. Statistical techniques have many purposes, which include methods and procedures for summarising, simplifying, reducing and presenting raw data. It then makes predictions, tests hypotheses and infers characteristics of a population from the characteristics of a sample.

Statistics is generally thought of as serving two functions. One is to describe sets of data; the other is to help in drawing inferences. Most research studies result in a large volume of raw data which must be suitably reduced so that the same can be read easily and can be used for further analysis. Classification and tabulation, achieve this objective to some extent, but we have to go a step further and develop certain indices or measures to summarise the collected/classified data. Only after this we can adopt the process of generalisation from small groups (i.e., samples) to population.

Thus the role of statistics in research is to function as a tool in designing research, analysing its data and drawing conclusions therefrom.

Statistical Softwares/packages

A statistical package is the software for the collection, organisation, interpretation, and presentation of numerical information. The need for a statistical package has arisen because of the complexity of calculations involved in making inferences from the data. The advances in computing technologies have made statistics a yet more powerful field.

The most widely used piece of statistical packages/ software for statistics is Excel. SPSS, SAS and Minitab.

SPSS (Statistical Package for the Social Sciences)

 SPSS is a versatile and responsive program designed to undertake a range of statistical procedures such as manipulating, analyzing, and presenting data; the package is widely used in the social and behavioral sciences. 

SPSS, (Statistical Package for the Social Sciences) is perhaps the most widely used statistics software package within human behavior research. It is widely used in Market research, Surveys, Competitor Analysis etc in the Field of Social Sciences. 

SPSS can easily compile data and perform analysis, or carry out more advanced statistical processing. It has a good range of statistics from descriptive methods (means, medians, frequencies etc.) to common tests (t-tests, regression, ANOVA) and some more advanced statistical measures (e.g. Factor analysis) It is user friendly.

Functionalities of SPSS

Some of the functionalities of SPSS includes the following

• Data Transformations
• Data Examination
• Descriptive statistics
• Correlation
• T-tests
• ANOVA
• MANOVA
• Regressions
• Factor analysis
• Cluster analysis and so on 

The SPSS Consists of 2 Sheets – One Is the Data View and the Variable View

 Features of SPSS

• It is easy for you to learn and use
• SPSS includes a lot of data management system and editing tools
• It offers in-depth statistical capabilities
• It offers an excellent plotting, reporting and presentation features

Benefits of SPSS

SPSS is considered the best tool to use since it makes possible

1. Effective data management- SPSS in data analysis easier and quicker - it reduces the manual work of the user to a great extent
2. Gives a wide range of options- SPSS offers a wide range of methods, graphs and charts . It also comes with better handling of the information as  a preparation for further analysis.

Aromatic Hydrocarbons

Aerobic Degradation

        Aromatic Hydrocarbons like Benzene, are acted upon by dioxygenases to labile cis cis-dihydrodiol that spontaneously convert to catechols. The dihydroxylated aromatic ring is opened by oxidative ortho cleavage resulting in “cis cis-muconic acid”. This is further converted to β-ketoadipic acid, which is oxidatively cleaved to the common tricarboxylic acid cycle intermediates, succinic acid and acetyl Co A. The catechols may also be opened by meta cleavage adjacent to hydroxyl groups yielding 2-hydroxy cis, cis muconic semialdehyde, which is further metabolized to formic acid, pyruvic acid and acetaldehyde.

                        

                        Bacteria oxidise aromatic hydrocarbons to cis diols whereas fungi and algae produce trans diols, which are carcinogenic

Condensed aromatic structures like naphthalene, if degradable, are attacked by dihydroxylation and opening of one of the rings. Opened ring is degraded to pyruvic acid and carbon dioxide. The second ring is attacked in the same manner.

           

Many condensed aromatic compounds are degraded with difficulty or not degraded. Cometabolism can help in degrading them. In presence of lower molecular weight aromatic compounds, in the environment, enzymes are induced which hydrolyse them and also polynuclear aromatic hydrocarbons, by cometabolism.

3 or 5 or more ring containing polyaromatic hydrocarbons eg., fluoranthene and pyrene, are degraded by cometabolism by bacteria such as Beijenrinckia and white rot fungi, Phanerochaete chrysosporium. One of the major problems in their degradation is their extremely low water solubility.

Anaerobic Degradation

Simple aromatics without hydroxyl, carbonyl or carboxyl substituents were thought not to be degraded under anaerobic conditions. However, Benzene, toluene etc are also degraded in anaerobic methanogenic conditions, as in composts, aquifers and sediments. Xylenes, ethyl benzenes also are degraded under similar conditions. For ring hydroxylation, oxygen is provided by water in these conditions

Acetic Acid- Vinegar-

 vinaigre (F) = sour wine

•         Acetic acid product-minimum of 4% of acetic acid

•         produced   by the process of double fermentation, alcoholic and acetous fermentation, from a suitable raw material of agricultural origin, containing starch, sugars or starch and sugars,

•         sugary/starch materials undergo alcoholic fermentation by yeasts followed by an acetuous one (oxidation of alcohol to acetic acid) by acetic acid bacteria

•         Commonly used in food preparations - pickling, salad dressings, sauces and mayonnaise

•         Variety of industrial, medical, horticultural and domestic uses

•         medicinal, laboratory, and cleaning purposes, cooking, baking, meat preservation, and pickling

Kinds of VINEGAR    

•         Raw material - Low cost raw material which supports the growth and metabolism of acetic acid bacteria

•         different starting materials - fruits, starchy vegetables, malted cereals,, sugars, spirits/alcohol etc

Product named as per the raw material used

•         Malt vinegar (alegar) - grains like barley

•         Wine vinegar - red or white wine

•         Sherry vinegar - Sherry wines

•         Cider vinegar - apple

•         Fruit vinegars - fruit wines, no additional flavoring - apple, raspberry, tomato etc

•         Balsamic vinegar from the concentrated juice, or must, of white grapes - an aromatic, aged type of vinegar - Italy –

•         Rice vinegar - East and Southeast Asia

•         Coconut vinegar, from fermented coconut water - Southeast Asia

•         Palm vinegar, from the fermented sap from flower clusters of palm - Philippines

•         Cane vinegar, from sugarcane juice - Philippines

•         Raisin, date, beer, flavored vinegars –fruits n herbs

•         Kombucha vinegar from kombucha, a symbiotic culture of yeast and bacteria - flavored by adding strawberries, blackberries, mint, or blueberries at the beginning of fermentation.

•         Distilled vinegar - Any type of vinegar may be distilled to produce a colorless solution of about 5% to 8% acetic acid in water -distilled spirit or "virgin" vinegar or white vinegar

•         Spirit vinegar - stronger variety (5% to 20% acetic acid) - made from sugar cane or from chemically produced acetic acid

 Microbial Fermentation Process 

 Two-stage fermentation

Ø  fermentable sugars are converted into ethanol by the action of yeasts (Alcoholic fermentation)

Ø  ethyl alcohol oxidized to acetic acid; by Acetobacter and Gluconobacter (Acetic acid fermentation)

Ø  Acetobacter/Glucunobacter - natural micro flora of plant products

Ø  Vinegar production are less susceptible to microbial contamination

Ø  pH of vinegar - 3 or below

Ø  Possible to carry it out in simple vessels such as open vats of wood or concrete

Ø  Acetic acid and Ethanol required for optimal growth of Acetobacter

Ø  Ethanol not less than 0.2% and not more than 5% (v/v)

Ø  The maximum concentration of acetic acid that can be produced by fermentation is usually around 10-15%

 Alcoholic fermentation

Ø  Sugar conc: 8-20%

Ø  Potassium and ammonium phosphates added if required (eg. With honey) – not needed in case of wine/apple juice.

Ø  pH 4.8-5. Temp: 28-30 degree celsius 3-7 days; in open fermentation vats

Ø  SO₂ added to inhibit the growth of contaminating microorganisms

Acetic Acid fermentation

Commercial vinegar production either by fast or slow fermentation processes.

Slow methods - traditional vinegars; fermentation proceeds slowly over the course of weeks or months-  Here, the fermenting liquid is not moved during acetification. Fruit juices or malt liquors are the starting material, usually eg., Open-vat (French/Orleans) method or home/let alone method –  culinary vinegar

Ø   The longer fermentation period allows for the accumulation of a nontoxic slime composed of acetic acid bacteria- mother of vinegar 

Fast methods - Here, the fermenting liquid is in motion- usually spirit/alcohol is the starting material for acetification. Add mother of vinegar to the fermenting liquid; provide aeration using a venturi pump system or a turbine to promote oxygenation to obtain the fastest fermentation. Vinegar produced in a period of 20 hours to three days. Eg., Trickle (Quick vinegar) method; Vinegar generator/fogging method, Bubble method; submerged (deep) fermentation

Mother of vinegar

-           A film of vinegar bacteria trapped in nontoxic slime at the top

-           Exocellulose produced by Acetobacter sp.  (aerobic; inhibited by salt)

-          Removed by filtering - Can be used as inoculum for a fresh batch of Vinegar

-          Produced only in slow methods

-           Slime production decreases as conc. of acetic acid in the finished product increases

-                

 

v  Home/Let alone method/Batch process

Ø  fermenting fresh fruit juice such as apple juice is allowed to undergo spontaneous alcoholic fermentation to produce about 11-13% alcohol., by yeasts present

Ø  Then a barrel is partially filled with fermented juice and allowed to undergo acetification, by acetic acid bacteria, naturally present, till vinegar is produced

Ø  Slow process; Low yield; inferior quality

v  Orleans Process/French method/Continuous process

•      Oldest and well known method for the production of vinegar

•      a slow, continuous process-fermentation in large (200 litre) capacity barrels

v  Wine or cider is fermented in wooden barrels or covered vats

v  A starter culture ie., Raw vinegar from a previous run added about 1/4^th or 1/5^th of the barrel–introduces active vinegar bacteria and acidifies the wine/malt liquor/cider –

v  Enough of alcoholicsolution  is added to the vinegar to fill about half of the barrel, leaving an air space above

v  The acetic acid bacteria growing on top as a film carry out oxidation of alcohol to acetic acid at about 29⁰C for weeks to months

v  Fermentation is continued until the acetification is complete

v  Part of vinegar bottled off; equal quantity of alcoholic liquor replaced in the barrel-about 3/4 of the vinegar drawn off and replaced with fresh wine or other fermentable liquid

v  The process repeated as long as quality vinegar can still be produced

v  Continuous process- Vinegar of very high quality

v  very slow (several weeks) and is usually done in small batches

v  Dropping of the film of vinegar bacteria during the process is avoided since it can interfere with the acetification process- use a floating framework which supports the film

v  Trickling (Rapid) generator(Schutzenbach) / German method

•      Orleans process is slow -Other methods to speed up the process

•      Generator method - German method

•      A simple generator is a cylindrical tank with two chambers -  larger (upper) chamber is packed with solid materials almost to the top (wood shavings, corncobs etc.) (bacteria attach to it) - separated from the lower chamber by a screen.

•      The tank is not allowed to fill as that would exclude oxygen which is necessary for the fermentation

•      The fermenting liquids –alcohol/spirit, usually, is fed through the top of the material, through a sparger/sprinkling device

•      It trickles down/ percolates through the solid material on which a slimy growth of acetic acid bacteria is developed, which oxidises alcohol to acetic acid.

•      Air enter through the bottom screen and through the solid materials & rises up

•      The resulting liquid is then pumped back to the top & recirculated until the alcohol content is reduced to ½ percent.

•      Once sufficient acetification is done, the vinegar is drawn off and fresh alcoholic solution is added. Some vinegar may be added to the fresh alcoholic solution to kick start acetification process

•      Fermentation process releases heat-so temperature maintained at 29-30⁰C-by using cooling coils, by adjusting the rate of feeding air and alcoholic liquid or by cooling the fermenting liquid that is recirculated

                      

Fring’s generator - Vinegar Generator

v  Mackin process/ fogging method

•      A fog or fine mist of a mixture of vinegar bacteria and nutrient alcohol solution is sprayed into a chamber

•      The mist is kept in circulation by filtered air and then allowed to settle at the bottom, cooled and the returned to the top.

•      The process is continued until oxidation of the alcohol (acetification) is complete.

 v  Dipping generator is a tank with a basket filled with beech wood shavings that can be raised out of or lowered into a dilute alcoholic solution in the lower part of the tank

•      While the basket is out of the liquid, aeration permits rapid acetification by vinegar bacteria attached on the shavings

•      When the basket is in the liquid, culture is added and produced vinegar is removed

 v  Submerged/deep fermentation (bubbling)

•         Stainless steel tanks, stirred from the bottom

•         Medium containing 8-12% alcohol inoculated with Acetobacter acetigenum and A. pasteurianum, maintained at 24-29 ⁰C with controlled aeration

•         Continuous stirring and agitation using propellers

•         Heat exchangers and foam eliminators used as per need

•         Production rate 10 times higher than surface fermentation and 5% higher than trickling generator process

•         Lower investment, low personnel requirement – complete automation

Acetator and Cavitator

•         Especially for vinegar production two different fermenters are designed - provide high aeration required.

•         Automatic temperature control is available.

•         Neither fermenter has shavings/packing material, therefore no clogging.

•         They are automated for charging with alcoholic solution and discharging of completed fermentation broth.

•         They are very small and highly efficient and produce acetic acid at  higher rate.

 •         Acetators operates in semibatch mode and cavitator in continuous mode. Aeration in acetator is by fast rotating ceramic disc over an air nozzle to provide finely dispersed air bubbles. Whereas in cavitator, nutrient liquid and air are sucked down a hollow tube extending from the liquid surface so that agitation and cavitation can cause air bubbles. 

Recovery

ü  Raw vinegar is normally cloudy with suspended bacteria and other particles

ü  Clarified by filtration

ü  Potassium ferricyanide used to decolourize the final product

ü  Product is either hot-filled into bottles after treatment or pasteurized in the bottle

Finishing

ü  After acetification, vinegar is usually matured in full closed vats for up to a year

ü  During this time, it develops its characteristic flavor and aroma and some settlement on unstable colloids takes place

ü   The preservative action of vinegar is due to its acetic acid content - inhibit the growth of most food poisoning and spore-forming bacteria

ü  Bacterial growth and turbidity in bottled vinegar can be prevented by a heat treatment- Gram negative acetic acid bacteria is not heat resistant, so use 60⁰C for few minutes is enough to eliminate the numbers encountered

ü  Individual vinegars - particular flavor according to the process and the raw material used

Vinegar Defects

ü   A haze or precipitate - in vinegars that have been in contact with non-acid resistant materials- due to the formation of iron and copper (metal-containing precipitates), which spoil the appearance of vinegar and make it unsuitable for use in pickling

ü  Microbial Contamination Lactobacillus or Leuconostoc species-off-flavours

Excessive sliminess caused by some vinegar bacteria such as Acetobacter xylinum which          interferes with acetification and lead to destruction of acetic acid

ü  Undesirable acid production by butyric acid bacteria, under anaerobic conditions. 

ü  Vinegar eels (Turbatrix aceti)

nematodes occurring in some forms of vinegar, if left open - occur in naturally fermenting vinegar- feed on the mother of vinegar

                   

Acetator & Cavitator