eChapters

Materials Required

Sensory scoring card, products, pen/pencil for coding, plain water.

Procedure

    1.    Take the given two samples
    2.    Make them three by duplicating/repeating either one of the two
    3.    Assign codes to the samples eg. AAB, ABA, ABB,  BAB etc.
    4.    Ask the evaluators to evaluate the samples for any differences between the 3 on the given Specimen Evaluation Card.
    5.    Find out how many of the evaluators have chosen the odd sample correctly (say it is 16 out of 20 evaluators).
    6.    Now find out the degree of difference in the samples indicated by the evaluators who correctly found the odd sample (Say it is much as per 3, moderate as per 8 and slight as per 5 out of the 16 correct evaluators.).
    7.    Find out how many of the correct evaluators preferred A sample and how many the B sample (say 11 preferred A sample and 5 B sample).
    8.    After going through Annexure II you may conclude that the two samples differed significantly from each other as 16 out of 20 evaluators found the odd sample correct. But, the preference was not significant as it should have been at least 13 out of 16 judges indicating same preference so as to make it significant. So, it may be concluded that the two samples differ significantly but both are acceptable.

Materials Required

Sensory scoring card, products, pen/ pencil for coding, plain water

Procedure

    1.    Assign codes to the samples i.e. a, b, c, …… or 1, 2, 3, ….. etc.
    2.    Keep the coded samples randomly (eg. c, f, a, b, d, e) in a row for evaluation
    3.    Start the evaluation of samples for various sensory attributes one by one. 
    4.    Evaluator should rinse his/ her mouth after each sample so as to avoid overlapping of taste, flavour etc.
    5.    Assign marks from 1-9 based on pleasurable and un pleasurable experiences.
    6.    Compute the means for a particular attribute on the basis of the evaluation of different evaluators (replications).
    7.    Find out the best sample on the basis of highest average scores obtained.

Materials Required

Soxhlet apparatus, petroleum ether, water bath, sample, grinder, weighing balance, filter paper, threads.

Procedure

    1.    Take the given sample and weigh it (A)
    2.    Dry the samples in an oven till there is no more weight loss and weight it (B)
    3.    Grind the sample into powder.
    4.    Place a weighed quantity of sample in filter paper, wrap the paper and tie it tightly with a thread so that no powder comes out of the paper during extraction. 
    5.    Pour approximately 100 ml of anhydrous ether into the bottom flask. Turn the heaters on. Set the temperature at about 40ºC.  
    6.    The ether will evaporate and circulate through the sample and again will come back to the flask. 
    7.    Repeat the process for about 16 – 18 hrs for complete extraction. 
    8.    Remove the sample and evaporate most of the ether from the mixture of crude fat and ether obtained during extraction.
    9.    Evaporate excess of ether from the crude fat sample by evaporation on a water bath. Evaporate till it is free from the fumes of ether. Record the weight (C).

Materials Required

Sample, Liebig condenser, digestion flasks (700-750 ml cap), conical flasks, filtering cloth (thick linen cloth for clear filtration) reagents, muffle furnace, crucibles.

Reagents

    1.    0.255 N Sulphuric acid solution : Dilute 2.5 g (1.36 ml) of concentrated H₂SO₄ to 200 ml. Ensure correct concentration by titration.
    2.    0.313 N Sodium hydroxide solution: 2.504 g NaOH / 200 ml water nearly free from sodium carbonate. Ensure correct concentration by titration.
    3.    Asbestos Chips: gooch grade, medium fibre, acid wash and ignited
    4.    10% Potassium sulphate (K₂SO₄) solution: Dissolve 10 g of Potassium Sulphate (AR) in water and make up to 100 ml.

Materials Required

Spectrophotometer, ethyl alcohol, beakers, pestle and mortar etc. 

Procedure

    1.     Preparation of sample extracts
        a.    Liquids : Centrifuge the juice at 5000 rpm for 4-5 min., and collect the supernatant. For liquid samples prepare a 40 % solution in ethyl alcohol. To 30 ml of the sample add 45 ml of ethyl alcohol and mix thoroughly. Filter through Watman 
No. 1 paper.

        b.    Semi-solid samples: To 15 g of blended sample add 15 ml of distilled water and 45 ml of ethyl alcohol. Mix thoroughly and filter through Watman No. 1 paper.
        c.    Dried products: Extract known quantity of sample (4-6 g) with 100 ml of 60% ethyl alcohol for 12 hrs and filter through Watman No. 1 filter paper.
    2.     Measure the absorbance of the samples at 440 nm for non-enzymatic browning and 400 or 420 nm for measurement of colour.
    3.     Prepare 60% ethyl alcohol solution as blank. Add 30 ml of distilled water to 45 ml of absolute alcohol and use as blank.

Materials Required

Ostwald viscometer, stop watch, sample, distilled water, thermometer.

Procedure

    a.    Take sample and distilled water. Record their temperatures (they should be same for correct estimation). If the temperatures are not same bring both to a specific temperature say 20ºC or the room temperature.
    b.    Clean and dry the Ostwald viscometer properly before use
    c.    Fill the ostwald viscometer with distilled water and record the time taken (T₁) for the a known volume of water to flow through the orifice.
    d.    Empty the viscometer and dry it
    e.    Fill the ostwald viscometer with sample juice or liquid and record the time taken (T₂) for the a known volume of sample to flow through the orifice of the same viscometer.
    f.    Calculate the relative viscosity using the following formula

Materials Required

Specific gravity bottles, weighing balance, sample, pipettes, thermometer, distilled water 

Procedure

    1.    Take the sample and distilled water record their temperatures (they should be same for correct estimation). If the temperatures are not same bring both to 20ºC or the room temperature.
    2.    Clean and dry the specific gravity bottles properly before use.
    3.    Record the tare weight of the specific gravity bottle (T) alongwith the stopper.
    4.    Carefully fill the specific gravity bottle with distilled water up to the brim and then place the stopper tightly so as to exclude extra water. 
    5.    Dry the exteriors of the bottle with a tissue paper
    6.    Record the weight of (bottle + water) say A
    7.    Similarly, fill the same specific gravity bottle with test sample and record the weight (bottle + sample) say B
    8.    Calculate the specific gravity of solution using the following formula

Materials Required

Sample, reagents, beakers, conical flasks, pestle and mortar, funnels, volumetric flasks, pipettes, weighing balance, spectrophotometer/colorimeter.

Reagents

    1.    2% Metaphosphoric Acid Solution: Weigh 20 g of HPO₃ and dilute to 1 litre in water or 4% oxalic acid.
    2.    Dye Solution: Dissolve 100 mg of 2, 6 Dichlorophenol-indophenol dye (Phenolindo-2,6- dichlorophenol sodium salt, AR, C₁₂H₆Cl₂NNaO₂ 2-3H₂O) and 84 mg of sodium bicarbonate (sodium hydrogen carbonate AR, NaHCO₃) in hot (85-95ºC) distilled water. Cool and make up the vol 100 ml. Filter and dilute 25 ml of the dye to 500 ml with distilled water. 
    3.    Standard Ascorbic Acid: Weigh 50 mg of ascorbic acid (AR) and make up to 50 ml with 2% metaphosphoric acid or 4% Oxalic acid solution (1000 ppm i.e. 1000 µg/ml). Dilute 4 ml of this solution to 100 ml with 2% HPO₃ or 4% oxalic acid. (1ml = 40 µg ascorbic acid).

Materials Required

Sample, reagents, beakers, conical flasks, pestle and mortar, funnels, volumetric flasks, pipettes, hot plate, weighing balance, spectrophotometer/colorimeter.

Reagents

    1.    0.1 N NaOH: Dissolve 4 g NaOH (AR) crystals in sufficient water to make up the final volume 1 Litre.
    2.    1 % Phenolphthalein: Dissolve 1 g in 100 ml water. Readymade indicator solutions are more commonly used.
    3.    Alkaline copper Tartarate
        a.    Dissolve 12.5 g anhydrous sodium carbonate, 10 g sodium bicarbonate, 12.5 g potassium sodium tartarate and 100 g anhydrous sodium sulphate in about 400 ml of distilled water and make up the final volume to 500 ml.
        b.    Dissolve 15 g copper sulphate in distilled water. Add one drop of sulphuric acid and make up to 100 ml in distilled water.
    4.    Always prepare fresh Alkaline Copper Tartarate reagent by mixing 96 ml of sol. a. and 4 ml of sol. b. and before use.
    5.     Arsenomolybdate Reagent: Dissolve 5.0 g ammonium molybdate (AR) in 90 ml of distilled water. Add about 5.0 ml of concentrated sulphuric acid and mix well. Add 600 mg of disodium hydrogen arsenate dissolved in 50 ml water. Mix well and incubate the prepared reagent at 37ºC for 24-48 hr or 55ºC for 30  min. with constant stirring.

Materials Required

Sample, 0.1 N NaOH solution, 1% phenolphthalein indicator solution, beakers, conical flasks, pestle and mortar, funnels, volumetric flasks, pipettes, pH meter, shaker.

Reagents

    1.    0.1 N NaOH: Dissolve 4 g NaOH (AR) crystals in sufficient water to make up the final vol. 1 litre.

    2.    1 % Phenolphthalein: Dissolve 1 g in 100 ml water. Readymade indicator solutions are more commonly used.  

Procedure

Preparation of sample: For fresh fruits and vegetables, prepare a well blended, uniform pulp in a pestle and mortar and for processed products, take out a representative sample and blend it well so that it becomes uniformly soluble when added to water. Filter through a fine muslin cloth or coarse filter paper if felt necessary. The liquid samples can be taken directly for estimation.
    1.    Take out a known weight / vol. (say 20 g) of sample in a beaker (in 3 replicates).
    2.    Make it to a known vol. (say 100 ml) with added distilled water.
    3.    Take 10 ml of this aliquot in a conical flask.
    4.    Add 1-2 drops of phenolphthalein indicator into the aliquot.
    5.    Titrate against 0.1 N solution of NaOH till light pink coloured end point is obtained.
    6.    For coloured products, i.e. tomato products where judgment of light pink colour is difficult, titration may be done over a shaker, and digital pH meter may be used for continuously measuring pH of aliquot which would show a steady increase with more and more addition of 0.1 N NaOH. Titre value may be recorded when pH of 8.3 is obtained.
    7.    Record the titre value and calculate the acidity of the sample as per the given formula.

Materials Required

Fruit/ sample, refractometers, thermometers, standard solutions of known TSS, temperature correction Tables.

Procedure

    1.    Calibrate refractometers of all ranges to be used.
    2.    The TSS of the juices/pulps/fresh fruits can be measured with the one having lowest range i.e. 0-32º Brix while, for measuring the TSS of concentrates, syrups, squashes, jams, jellies etc. refractometers of the higher ranges are made use of.
    3.    Put a drop of material on to the glass surface of refrectrometer’s prism, cover gently with the lid and observe the TSS against light.
    4.    Measure the temperature of the liquid which is being evaluated and apply temperature corrections (Annexure III).
    5.    Record the corrected value as the TSS of the sample.

Materials Required

Sample, hot air oven, weighing balance, crucibles, muffle furnace, lead pencil / marker etc.

Procedure

    1.    After following the procedure for the determination of moisture (in silica crucibles as given in previous chapter) the same sample can be used for the determination of ash. 
    2.    Heat the dried sample in the silica crucibles over a heater/hot plate/burner to burn the carbon.
    3.    When it becomes completely black and no more smoke comes out of the sample, shift them to muffle furnace.
    4.    After heating the samples in muffle furnace, all the marks of pen / pencil/ marker are lost, so one would not be able to identify the samples and error of weights may occur. Therefore, it is advised to place the samples in the furnace in one or two rows and draw the diagram on a piece of paper for identification purpose.

Materials Required

Fruit, vegetable or product sample, hot air oven, weighing balance, crucibles, petri plates, lead pencil / marker etc.

Procedure

    1.    Take crucibles  or petri plates and record the tare weight of crucibles / petri plates (C) and mark them
    2.    Cut the sample into small and thin pieces (if solid)
    3.    Put the sample into the crucibles / petri plates in three replications
    4.    Record the weight of crucibles + sample (C + S)
    5.    Put in hot air oven for drying at 70 + 2ºC.
    6.    Record the loss in weight after every 1-2 hrs till it becomes constant
    7.    Calculate the moisture and total solids. 

Materials Required

Cut flowers, 1000 ml conical flasks, scissor, tape, distilled water, chemicals, weighing balance, volumetric flasks, labels, thermometer (max. & min. type) and hygrometer. 

Procedure

    1.    Collect fresh spikes of flowers
    2.    Cut at the base keeping about 25-60 cm of the cut flowers stick (uniformly for each flower).
    3.    Prepare Pulsing/ Vase solutions.
    4.    Put the prepared flower spikes in labeled conical flasks containing different Pulsing/ Vase solutions (for a known period of time).
    5.    Record the weight of the spikes and other observations daily.
    6.    Record the temperature and relative humidity of the storage chamber daily.
    7.    Analyse the recorded data and draw conclusion about the best vase solutions for the selected cut flower.

Materials Required

Apple (or any local fruit), fruit mill, hydraulic press, weighing balance, Refractometer/sugar pectinol, diammonium hydrogen phosphate, Saccharomyces cerevisiae culture, Potassium metabisulphite (KMS) etc.

Procedure

    1.    Take a known quantity of apple (or any other fruit) say 20 Kg
    2.    Extract the juice as discussed in earlier exercises.
    3.    Add about 200 ppm of kms.
    4.    Add sugar syrup to increase the TSS to about 20 – 24ºBrix.
    5.    To about 10 Kg of juice diammonium hydrogen phosphate (10 g) and pectinol (20-25 g are added).
    6.    Take about 500 ml of this mixture in a conical flask and add pure Saccharomyces cerevisiae culture @ 1 % and plug the neck with cotton. Keep at 22-24ºC to complete the fermentation within one day and yeast culture is ready.
    7.    Add this culture to about 10 Kg of must for further fermentation (i.e. culture is added @ 5% therefore 500 g is added to 10 Kg must).
    8.    Record the TSS of the must before fermentation.
    9.    Keep must for fermentation in big jars (narrow mouth) filled to about 75 % of their volume. Close the mouth of jars or bottles with cotton plug.
    10.    Allow fermentation to take place at 22-24ºC for about 10–15 days.
    11.    When no more bubbles are coming out of the jars, fermentation is complete. At this stage the TSS reaches about 7º Brix.
    12.    Siphon the wine. Add filter aids if wine is not clear.
    13.    Blend the wine with sweetening agents if required.
    14.    Fill in beer bottles by keeping a head space of about 2.5 cm followed by crown corking them.
    15.    Pasteurize the bottles by keeping at 62.5ºC for 20 min.

Materials Required

Dehydrator, balance, thermometer, sulphur dioxide, blanching pan, fruits / vegetables, polythene or aluminium bags.

Procedure

    1.    Select sound fruits or vegetables 
    2.    Record their initial weight and wash them properly in plain water to remove any dirt or extraneous matter. 
    3.    Peel with stainless steel knife (as the case may be) and cut into thin uniform pieces or slices of  0.2-0.5 mm thickness
    4.    Blanch the slices in boiling water for 1-2 min. to inactivate the enzymes followed by immediate cooling.
    5.    Treat the slices with sulphur (sulphuring or sulphiting) in order to prevent darkening of the product during drying. 
    6.    Dry the slices in a mechanical air dehydrator at about 55 + 5oC temperature.
    7.    Record the weight of the product after every 2 hr till it becomes (almost) constant i.e. when there no more (significant) loss of moisture from the product.
    8.    Pack the product in ploythene or aluminium laminated pouches and seal them air tight. 
    9.    If it is to be converted into powder, the dried product can be ground in a grinder before packing.
    10.    Label the packages and store them in a cool dry place.
    11.    Plot the drying rate curve of the product on a graph paper and analyse it.
    12.    Record the initial and final moisture content of the product (as discussed in Exercise No. 19). 

Materials Required

Canned product, weighing balance, can cutter, vacuum/pressure guage, seam checking guage, Refractometer / Salometer etc. 

Procedure

    1.    Take a canned product say canned peach.
    2.    Record the weight of the can (A)
    3.    Record the information marked on the label i.e net  weight, date of packing, etc
    4.    Observe the can externally for the concavity of the lid.
    5.    Record the vacuum of the can by using a vacuum guage
    6.    Cut the lid of the can with a can cutter
    7.    Record the head space
    8.    Put all the contents over a sieve and let the liquid drain
    9.    Record the weight of empty can (B) to calculate net contents
    10.    Record the drained weight of the pieces.
    11.    Record whether the liquid is syrup or brine
    12.    Record the TSS of the salometer reading of the liquid (as the case may be)

Materials Required

Fruits or vegetables, stainless steel knife, steel pans, Can Body Reformer, Flanger, Double seamer, weighing balance, Refractometer / Salometer, sugar or salt etc. 

Procedure

    1.    Wash the selected fruit or vegetable (as the case may be) 
    2.    Cut into pieces or slices (the size and shape may depend on the fruit/ vegetable but it should not be too large or too small)
    3.    Blanch the material in boiling water for 1-2 min for effective inactivation of enzymes. 
    4.    Prepare the sugar syrup of strength 40o Brix or brine of 1-3 % strength.
    5.    Prepare the can body using a can body reformer and flange the ends in a flanger.
    6.    Seal the base plate using first and second roller operations of the double seamer. 
    7.    Transfer the prepared fruits / vegetables into the cans. 
    8.    Pour in hot syrup or brine into the cans.
    9.    Place the lid over the top of filled can. (follow the first roller operation of the double seamer, if the cans are OTS cans)
    10.    Exhaust the cans in boiling water for about 10 min. to exclude any dissolved air out of the tissues or syrup/brine.
    11.    When the temperature of the centre of can reaches 79-80 ºC for fruits or 82ºC for vegetables, remove the cans from the exhaust box and seal them properly (follow the second roller operation of the double seamer, if the cans are OTS can).
    12.    Process the sealed cans at 100ºC and 115-121ºC for fruits and vegetables respectively for 15-30 min in case of fruits and 25-45 min. in case of vegetables.
    13.    Cool the cans immediately in cold water and air dry them at room temperature.
    14.    Label and store in a cool dry place.

Materials Required

Tomato fruits, pulper, steel pans, weighing balance, refractometer, sugar, salt, spices, acetic acid, citric acid, muslin cloth etc.

Procedure
I. Puree

    1.    Extract fruit pulp by Hot process as told by the teacher.
    2.    Record the TSS of the pulp.
    3.    Concentrate the pulp by heating to 12º Brix (heavy puree)
    4.    Hot fill the boiling puree into pre-sterilized glass bottles (200 ml cap.)
    5.    Seal the bottles by crown corking
    6.    Heat process in boiling water in a big aluminium pan for 15-20 min. 
    7.    Cool the bottles to room temperature as quickly as possible.
    8.    Label and store at a dry place.

Materials Required

Fruits or fruit pulp, steel pans, weighing balance, refractometer, sugar, salt, spices, acetic acid, citric acid etc. 

Procedure

    1.    Extract fruit pulp as told in earlier exercises. 
    2.    Take a known quantity of freshly extracted or preserved pulp.
    3.    Weigh sugar (about half the weigh of pulp).
    4.    Heat pulp and sugar over a gas flame.
    5.    Add spices, chillies, salt, citric acid (if required) etc. and cook
    6.    Record the TSS to judge the end point. It should be more than 50o Brix.
    7.    Add measured quantities of acetic acid and sodium benzoate at the end.
    8.    Cool and pack in pre-washed and sterilized glass jars
    9.    Label and store.

Materials Required

Lime fruits, green chillies, ginger salt (common), stainless steel pans, kinives, weighing balance, spices etc. 

Procedure

    1.    Select sound and mature fruits of lime, mature but green chillies having good size and ginger rhizomes.
    2.    Wash the lime fruits, ginger and chillies properly in running cold water.
    3.    Cut the lime fruits into pieces / halves. 
    4.    Remove the stalks of the chillies and cut into longitudinal slices. Peel ginger and cut into long thin slices.
    5.    Put the lime pieces, chilli and ginger slices in a wide mouthed pre-sterilized glass jar 
    6.    Add common salt @ 250g / Kg of material.
    7.    Squeeze some of the juice over the slices
    8.    Stir the mass well mixing thoroughly
    9.    In case the juice does not cover the material completely, add pre-boiled and cooled 5% solution of citric acid.
    10.    Keep the jar in Sun for about a week with occasional shaking of the material.
    11.    When the lime pieces start turning light brown, the pickle is ready for consumption.

Materials Required

Fruit extract, cane sugar, potable water, essence, citric acid, colours, preservatives, weighing balance, glass jars (500 ml capacity), jar closures, hand refractometer, steel pan, ladle etc.

Procedure for Jelly

    1.    Select sound and fresh fruits, free from any blemishes. Generally a mixture of ripe and unripe fruits shouldbe taken as the ripe fruits impart good flavour and the unripe fruits are rich in pectin, required for a good set.
    2.    Wash the fruits thoroughly. Cut into 4-8 pieces depending upon the fruit and size
    3.    Boil the fruit pieces in water (about ½ to an equal weight of fruits for fruits like apple and 2-3 times the weight of sliced fruits in case of citrus fruits) for about 30 min. with occasional stirring. Strain the boiled mixture through coarse muslin cloth to get a clear pectin extract
    4.    A second extract may also be taken by boiling the same mass again and straining.
    5.    Add sugar (usually 3/4th to one part of the extract or in 45:55 ratio) to the pectin extract and boil in a stainless steel pan. Add required quantities of acid towards the end of boiling.
    6.    Remove the scum rising on the top of boiling mass occasionally.
    7.    To avoid charring, occasional stirring is also done.
    8.    To avoid destruction of pectin the cooking should be completed fast
    9.    Determine the end point of jelly as detailed ahead.
    10.    Fill in hot dry glass jars and cool rapidly
    11.    Pour a thin layer of hot molten paraffin wax seal to avoid moulding.   
    12.    Label and store in a cool place.

Materials Required

Fruit pulp, cane sugar, potable water, essence, citric acid, colours, preservatives, weighing balance, glass jars (500 ml capacity), jar closures, hand refractometer, steel pan, ladle etc.

Procedure

    1.    Select sound and fresh fruits, free from any blemishes. Generally a mixture of ripe and unripe fruits should be taken as the ripe fruits impart good flavour and the unripe fruits are rich in pectin, required for a good set.

    2.    Wash the fruits thoroughly. Cut into 4-8 pieces depending upon the fruit and size
    3.    Boil the fruit pieces for about 20-25 min in boiling water and pass through pulper to get a good pulp.
    4.    Weigh known quantity of fresh or preserved pulp and add about equal quantity of sugar (preferably in 45:55 ratio)
    5.    Cook the mixture on gas flame by occasional stirring. 
    6.    When the mixture becomes thick, perform sheet test.
    7.    Citric acid is added generally towards the end of cooking. Addition of all the acid in the beginning may result in stickiness and poor set. 
    8.    Remove from the flame when the mixture gives a clear sheet
    9.    Flavours, colours etc may also be added towards the end of boiling. 
    10.    Fill the jam in glass jars (preferably pre-warmed in hot air).
    11.    Close the jars with lug caps and allow to cool overnight.
    12.    Label and store in a cool place.

Materials Required

Fruits juice, enzymes (pectinase, cellulase, pectinase CCM etc.), filter press, buchner filter apparatus, water bath, filter paper pulp, buchhi type rotary vacuum evaporator, freeze concentrator, membrane concentrator (whichever available), vacuum grease.

Procedure

    1.    Extract the juice as discussed in earlier exercises. Take a known quantity of juice in a conical flask.
    2.    Add enzymes i.e. pectinase @ 0.2% to the juice and keep in a water bath at temperature of 40-50ºC for 2 hrs.
    3.    Shake the flasks occasionally for uniform mixing of enzyme all throughout the flask during the enzymatic treatment.
    4.    Leave the flasks undisturbed for 10-12 hrs for allowing the insoluble solids to settle at the bottom of the flask.
    5.    Siphon the clear juice from the top of the flask.
    6.    Pass this siphoned juice through filter press or through a 0.4-0.5 cm thick bed of filter paper pulp in a Buchner filter apparatus or filter press.
    7.    Record the volume of the clarified juice obtained. Calculate the wastage.
    8.    Concentrate the juice in rotary vacuum evaporator at 50+2ºC temperature and at 28-30” Hg vacuum to a TSS of about 50 to 70º Brix. Record the exact TSS.
    9.    Record the volume of condensate obtained in the round bottom flask of the buchhi apparatus.
    10.    Calculate the folds of concentration

Materials Required

Fruit juice/ pulp, cane sugar, potable water, essence, citric acid, colours, preservatives, weighing balance, bottling and sealing facilities, hand refractometer, homogenizer etc.  

Procedure

    1.    Extract the juice as discussed in previous exercise.
    2.    Filter the fresh or preserved juice through muslin cloth.
    3.    Calculate the quantities of juice, sugar, water, acid (if required), preservatives, colour, essence etc. required for preparation of a known quantity of                      squash as per FPO specifications.
    4.    Prepare the beverage as directed by instructor
    5.    Pack the beverage in bottles 
    6.    Seal the bottles and label them
    7.    Take out one of the bottles and measure its TSS and titratable acidity.

Materials Required

Fruit, pulper, fruit mill, hydraulic press, screw type juice extractor, stainless steel pans, chemical preservatives, glass bottles, closures, crown corks, crown corking machine, plastic barrels.

Procedure

    1.    Select and weigh sound fruits/vegetables for extraction of juice/pulp.    
    2.    Wash and peel the fruits as required.
    3.    Extract the juice by hot or cold process.
    4.    Pasteurize the juice/pulp to inactivate the enzymes and partially kill microorganisms.
    5.    Preserve the juice/pulp by heat processing after hot filling and hermetic sealing or by addition of permissible quantities of suitable preservatives.
    6.    Label the bottles properly and keep them for storage

Materials Required

Fruits/ vegetables, weighing balance, plastic crates, CFB boxes or other packaging material fruit pressure tester, hand refractometer, markers etc.

Procedure

    1.    Harvest the fruits
    2.    Subject them to various pre-treatments (as discussed in previous exercise).
    3.    Record their initial parameters i.e. weight, firmness, surface colour, TSS, rotting etc. 
    4.    Place properly packed commodity in storage alongwith a check under ambient conditions
    5.    Record the observations regarding changes in quality during storage
 

Materials Required

Fruits/ vegetables, washing tanks/ containers, size grader, fruit waxes, packaging material, neem based fungicides etc. 

Procedure

    1.    Take available fruits or vegetables 
    2.    Wash them in plain water or chemical solution as told by the teacher
    3.    Shade dry the fruits / vegetables
    4.    Prepare suitable wax solution
    5.    Apply wax on to the fruits as told
    6.    Record the fruit weight before packing
    7.    Pack the fruits properly in the trays / boxes depending upon the type and purpose
    8.    Do curing if required 
    9.    Do pre-packaging, if desired
    10.    Label the package for desired information
    11.    Keep the fruits for storage
    12.    Record the observations pertaining to weight loss and rotting periodically depending upon the commodity and its shelf life.

Materials Required

Fruits/vegetables, thermometer, refractometers, NaOH, Phenolphthalein, glassware, weighing balance, plastic crates for storage of commodity, water cooling facility.

Procedure

    1.    Harvest the fruit / vegetable
    2.    Count No. of unmarketable fruits in every 100 fruits harvested
    3.    Record the internal fruit temperature in about 5-10 randomly selected fruits with the help of a thermometer
    4.    Pre-cool the commodity in cold water (<5ºC), air or refrigerator till the temperature reaches near its optimum storage temperature
    5.    Record the internal fruit temperature
    6.    Record the time required to pre-cool the commodity
    7.    Keep the product for storage at ambient conditions alongwith control
    8.    Record the difference in the shelf life and quality during storage

Materials Required 

Fruits/vegetables, hand refractometers, fruit pressure tester, weighing balance, scale, chemicals and glassware required for analysis.

Procedure

    1.    Go to the orchard or vegetable field and collect samples of fruits and vegetables
    2.    Apply the specific maturity indices to the samples

Materials Required

Equipments and machinery used in Postharvest Technology laboratory for processing, packaging and quality analysis.

Procedure

    1.    Identify the equipments and machinery, note down the typical features about its shape, size, colour etc.

The word ‘chlamydia’ comes from the Greek word ‘chlamys’ which means, “cloak draped around the shoulder”. This describes how the intracytoplasmic inclusions caused by the bacterium are “draped” around the infected cell’s nucleus. Chlamydia was first discovered by a Czech zoologist and parasitologist, Stanislaus von Prowazek in 1907 in Berlin, but scientists believe it was actively infecting people for centuries before its discovery. Because the symptoms of Chlamydia are similar to some other infections it was not identified as a sexually transmitted disease. Originally, because of its structure it was thought to be a virus. In 1963 it was recognized as bacteria rather than a virus.

Properties of genus

           They are poorly stained by Gram’s stain. Chlamydiae are readily stained by Castaneda (blue in appearance), Giemnez and Macchiavello (red in appearance) methods. However, Giemsa staining is preferable to stain the inclusions (Chlamydial micro colony) in the cell culture. Inclusion bodies of the Chlamydiae are basophilic in nature. Again, the staining of the inclusion bodies may differ depending on the species. In C. trachomatis, the inclusion bodies contain glycogen matrix and can be easily stained with iodine solution.

History of Rickettsial infections went back to 16^th century and it has long been associated with famine and war. Thus Rickettsial infections played a significant role in the history of Western civilization. Epidemic typhus had major impact to decide over the outcome of several wars. This epidemic alone killed or caused great suffering to over 100,000 people in the two World Wars.  However, the causative agent was not determined until the early part of the 20^th century. Rocky Mountain Spotted Fever (RMSF) was the first detected Rickettsial infection as early as in 1896 in Idaho Valley, USA.  It was originally known as ‘Black Measles’ because of its clinical appearance in the form of characteristic spotted rash appearance throughout the body of the patients. Howard Taylor Ricketts, an American pathologist for the first time described the causative agent of Rocky Mountain spotted fever and was able to isolate it in the laboratory animals during 1902-1909. He was a dedicated scientist and, on several occasions, injected himself with a pathogen for experiment. The causative pathogen of Rocky Mountain spotted fever, Rickettsia rickettsii was named after him. Later, the family Rickettsiaceae as well as the order Rickettsiales was named after him. Ernest William Goodpasture, an American pathologist and physician, invented the methods of isolation and culturing the rickettsial pathogens in chicken embryos and fertilized chicken eggs.

The name Mycoplasma is originated from the Greek word mykes (fungus) and plasma (formed). It was first used by Albert Bernhard Frank, a German Biologist in 1889. He thought it was a fungus. An older name for Mycoplasma was Pleuropneumonia-Like Organisms (PPLO), referring to organisms similar to the causative agent of contagious bovine pleuropneumonia (CBPP). It was later found that the fungus-like growth pattern of M. mycoides is unique to that species. It was first isolated in 1898 by Edmond Nocard and E. Roux from bovine lungs. Whereas, Mycoplasma pneumoniae was considered as a virus previously. Eaton and his co-workers cultured the causative agent of human primary atypical pneumonia (PAP) or "walking pneumonia." It was known as "Eaton's agent." In the early 1960s, Leonard Hayflick, in Philadelphia, was first to isolate and cultivate the causative agent of primary atypical pneumonia and identified the agent as a Mycoplasma and named it Mycoplasma pneumoniae.

Properties

1. Bacteroides, Dichelobacter and Fusobacterium are major gram negative anaerobes isolated from human and animals. Other gram negative anaerobes are listed below (Table-1).

       2.   They are tolerant to oxygen in comparison to strict anaerobes. They do not die after oxygen exposure

       3.         They naturally inhabit the intestine and mucosal surfaces of human and animals. Majority of them are opportunistic pathogens. Often they cause mixed bacterial infection along with aerobes. Aerobes remove oxygen and create an anaerobic condition favourable for their growth. Aerobes may also supply other growth requirements. For e.g. Porphyromonas asaccharolytica requires vitamin K for its growth, supplied by another bacterium, not the host.

Leptospira 

Antony Van Leeuwenhoek (1681) first observed the Spirochaetes under the microscope and described them. In 1833, Ehrenberg used the name Spirochaeta for free living spiral shaped organisms. Obermeir (1873) first described a Spirochaete of pathogenic significance isolated from human patients of relapsing fever. Inada et al. (1916) first isolated Leptospira icterohaemorrhagiae from human patients of Weil’s disease. In 1980, Nogochi proposed the name Leptospira.

      In India, Taylor and Goyale (1931) first reported Leptospira from human patients suffering from jaundice in Andaman Islands (Srivastava, 2006). Ayyar (1932) first reported Leptospira from dogs in Chennai city. 

Properties of genus

1. Morphology : Leptospira are gram negative, spiral shaped organisms with hooked ends. Length varies from 6-20 µm with 0.1-0.2 μm diameter (Fig.1). They have a typical double membrane covering. The cytoplasmic membrane and peptidoglycan cell wall are closely associated and are surrounded by an outer membrane. Two periplasmic flagella (endoflagella) are found within the cell and are responsible for the motility. No flagella are present as extracellular appendages. One end of the flagella is attached with the pole of the bacterial cell by insertion disc. Other end extends towards the centre of the cell and may overlap the flagella coming from the opposite end. The endoflagella consists of a solid inner core surrounded by tubular sheaths. The FlaA and FlaB proteins constitute these flagellar sheath and core, respectively.

Dermatophilus congolensis was first described from clinical case of exudative dermatitis in cattle in Congo by Van Saceghem (Van Saceghem, 1915). It is primarily known as an animal pathogen causing acute, sub acute or chronic skin disease. The first cases of human infection with D. congolensis were reported in 1961 in four people who developed skin infection after handling an infected deer in a wildlife reserve in USA (Dean et al., 1961).

Properties of genus

1.   Morphology

Dermatophilus is a gram positive, non-acid fast, unusual bacterium having branched filaments. It follows a life cycle with different morphological features. It can be found in smears prepared from clinical samples in any form of its life cycle. Young filaments are 0.5 to 1.5 μm in diameter.  They enlarge within epidermis as they produce layers of transverse and longitudinal septations and reach 5 to 8 μm in diameter, surrounded by a mucoid capsule. The septations result in the formation of a sporangia (a kind of fungal fruiting body, sac like structure with spores) containing up to eight cocci cells. In the presence of liquid, the cocci are released and converted into flagellated motile zoospores, the infective form of the organism. It can infect the new site in the same animal or new host. These zoospores become visible in smear as parallel lines forming a ‘railway-track’ or ‘trum-track’ appearance (Fig.1). Under favourable conditions, the zoospores form germ tubes that develop into branching filaments. These filaments are the invasive form of the organism and the cycle is repeated.

Edmond Nocard (French Veterinarian) first isolated filamentous aerobic bacteria from clinical cases of ‘bovine farcy’ in 1888. In 1889, the genus Nocardia was formed by Trevisan, and the organism described by Nocard was named as Nocardia farcinica. In 1891 another similar organism (Nocardia asteroides) was isolated by Eppinger from a human brain abscess. Initially it was thought that they are the same organisms. Latter on the basis of the molecular studies their separate entity is established.

            However, 80 years later, re-examination of Nocard’s original isolate revealed two different filamentous organisms, one of which was Mycobacterium and the other was Nocardia. The cause of ‘bovine farcy’ has been subsequently attributed to Mycobacterium. Latter, it is proved that Mycobacterium farcinogenes is the actual causative agent of ‘bovine farcy’.

Corynebacterium diptheriae was first observed by Klebs in 1883 and described in details by Loeffler in 1884. So it is also known as ‘Klebs-Loeffler bacillus’. In 1888, Nocard isolated a similar type of bacteria from cases of bovine farcy. In 1894, Preisz described it completely and revealed its similarities with the diphtheria bacilli. Latter it was named as Corynebacterium pseudotuberculosis (Preisz-Nocard bacillus). Bollinger (1890) first reported C. renale from the cases of pyelonephritis in cows. Magnusson (1923) first described C. equi (Rhodococcus equi) form suppurative pneumonia of a foal.

Properties of genus

1.   Morphology

Corynebacterium are gram positive, pleomorphic bacteria ranging from coccoid to filamentous rods. The size varies from 0.5-0.6 µm by 1.0- 3.0 µm. Some of the species appear as packets of parallel cells (palisade arrangement) or show ‘V’ shaped form (Chinese letter arrangement) in the microscopic field (Fig.1and Fig.2). The cell wall peptidoglycan contains meso-diaminopimelic acid (meso-DAP). The arabinose and galactose are major cell wall sugars. Short-chain mycolic acids (corynomycolic acids, 22–36 carbon atoms) are present. This kind of cell wall structure is impermeable to the hydrophilic compounds. However, the ‘porin’ present in the cell wall sometimes helps in import of the hydrophilic substances. Mycolic acid containing cell wall helps in intracellular survival within the macrophages. Corynebacterium is non acid fast, non-sporulating, non-capsulated and non-motile bacteria (except C. aquaticum)
.

The genus Arcanobacterium was first described to include the bacteria originally isolated as Corynebacterium haemolyticum from American wounded soldiers (Collins et al., 1982). The bacteria had different cell wall and lipid composition in comparison to the other members of the genus Corynebacterium. So the new genus Arcanobacterium was created.

Properties of genus

1.         Morphology : Arcanobacterium pyogenes is a Gram positive, non-motile, non- spore forming, short, rod-shaped bacterium, measuring 0.5µm by 2 µm. They are non-capsulated and do not contain any metachromatic granule. Initially (during first 18 hour of growth) the bacterial cells may show characteristic ‘V’-arrangement like Corynebacterium, latter as the growth proceeds, the organisms become granular and segmented so that they resemble small and irregular cocci (whereas, A. hippocoleae and A. pluranimalium appear to be less coccoid). The cell wall is devoid of mycolic acid, arabinogalactan unlike ‘coryneform’ bacterial group (Mycobacterium, Corynebacterium, Rhodococcus, Nocardia). Cell wall peptidoglycan is composed of N-acetyl muramic acid, lysine. Being gram positive in nature, some strains exceptionally possess fimbriae.

Cohn (1875) first observed and described a branching filamentous micro-organism in the concretions (coagulated mass) taken from a lacrimal canal, latter identified as Actinomyces israelii. Bollinger first reported the yellow granules in jaw tissues of the cattle in 1877 and established the significance of the organisms as an etiological agent. In 1878, Israel described the first human case. In 1879, Hartz observed the microscopic appearance of granules of Actinomyces infection and suggested the name Actinomyces bovis. Mosselman & Lihnaux (1890) and Wolf &Israel (1891) first isolated the bacteria in artificial laboratory media from lumpy jaw cases of cattle and human Actinomycosis, respectively.

Properties of genus

1.         Morphology :  Actinomyces are gram positive filamentous organisms with branching rods. In artificial media, short bacilli or cocci forms are also observed. During infection, they can produce yellow coloured granules (sulphur granule), commonly found in the pus as ‘opaque speck’ and are visible under naked eye (1-2 mm in diameter). The granules are usually soft and easily broken under light pressure, but they may occasionally be tough or even calcified. They are composed of club shaped bodies, arranged radially with their narrow ends towards the centre. So the organisms are also known as ‘ray fungus’. In the centre of the club, filamentous masses of gram positive organisms with some bacilli or cocci form are found. Together the club like processes and bacterial masses are known as ‘rosette’ (Fig.1). This club is composed of calcium phosphate and inflammatory debris
.

Lignieres and Spitz first isolated the bacteria from the cattle with Actinomycosis like condition in Argentina in 1902. They referred them as ‘Actinobacilllus’. These findings were also confirmed by Nocard in 1902. Latter, the isolated bacterium from the cattle was named as Actinobacillus lignieresii, in memory of Lignieres. 

Properties of genus

1.   Morphology :  Actinobacillus are gram negative small rods, measuring 1.5 µm in length and 0.4 µm in width, occurring singly, in pairs or more rarely in chains. After isolation in the laboratory they may show pleomorphism varying from coccobacilli to filamentous forms. In gram stained smear they may show both bacillus and coccus form together, known as ‘morse code’ appearance (dots and dashes appearance, Fig.1). They are non-motile (both at room temperature and 37^oC), non-sporing and non-acid fast. The pili are found in A. pleuropneumoniae.

      Some of them (A. pleuropneumoniae) are capsulated. Whereas, slime layer is found in the surface of other species like A. lignieresii, A. suis, A. equuli.  This slime layer is related with stickiness of the colonies in the agar, enhanced resistance of the colonies to the chemical disinfectants, as well as, resistance of the bacterial cell to the antibiotics and desiccation.

2.         Actinobacillus are aerobic, microaerophilic or facultative anaerobic in nature. They are chemoorganothrophic having both respiratory and fermentative types of metabolism.

Listeria

Murray et al. (1926) first described about Listeria which was followed by Pirie et al. (1927). In India Listeriosis was first reported by Mahajan (1936) in sheep from Andhrapradesh. He recognized it as ‘circling disease’. Latter a number of reports are available from various parts of India.

Taylorella was first isolated by Taylor et al. (1978) as a causative agent of contagious equine metritis (CEM), a venereal disease of horses. The disease (CEM) was first reported in the mares of thoroughbred horses in UK in 1977 breeding season (Crowhurst, 1977). Initially the causative agent was assumed as Haemophilus equigenitalis. Later on the basis of numerical taxonomic characteristics, genomic G+C contents, DNA-DNA hybridisation studies, the new genus Taylorella was proposed in 1983 (Sugimoto et al., 1983). It was approved by the International Committee on Systematic Bacteriology.

Properties of genus

1.   Morphology :  Taylorella are gram negative, small rods or coccobacilli, measuring 5-6 µm by 0.8 µm. They are pleomorphic, piliated, encapsulated, non-sporing and non-motile.

2.   They are microaerophilic (require low O₂ tension for growth), non-fermentative, and non-proteolytic in nature.

3.         Classification : Taylorella belongs to β- subclass of class Proteobacteria (whereas, Haemophilus belongs to the γ- subclass of Proteobacteria). Major important species is Taylorella equigenitalis. The genus was considered as a ‘single species genus’ for a long time. Latter in   1997, National Veterinary Services Laboratories confirmed the identity of another Taylorella species, isolated from a donkey jack (Equus asinus) in California. It was named as T. asinigenitalis. The new species has minor difference in 16S rDNA sequence (97.6% similarity), DNA–DNA hybridization (23% similarity) and (G + C) composition with T. equigenitalis (Matsuda and Moore, 2003)
.

Pfeiffer first isolated and described Haemophilus influenzae as a cause of human influenza (1892). So it is also known as ‘Pfeiffer’s bacillus’. Later other workers isolated and described different species of the genus Haemophilus from animals and birds. In 1903, Friedberger, a research assistant of Pfeiffer, isolated similar kind of organism from prepuce of the dogs. In 1922, Rivers described it as Haemophilus canis. In 1925, Mitchell isolated Haemophilus ovis from the respiratory tract of sheep. In 1931, Lewis and Shope first isolated and illustrated Haemophilus suis from the infected pigs. Glasser found an association between fibrinous serositis, polyarthritis in pigs (Glasser’s disease) and a small gram negative rod as early as 1910, latter became known as Haemophilus parasuis. It was first isolated by Hjarre and Wramby in 1943.  The first recorded isolation of a hemophilic organism from the birds was in 1931 by De Blieck and he called them as Bacillus haemoglobinophilus coryzae gallinarum. He isolated them from the chickens suffering a disease, now known as ‘infectious coryza’.

The genus was named after Morax who first isolated the organisms from human conjunctivitis in 1896.

Properties of genus

1.   Morphology :  Moraxella are gram negative, small rods occurring in pair (diplobacilli). The aged cultures exhibit pleomorphism, occurring in pairs or chains as short, plump rods with rounded ends. Some strains may appear as cocci. The capsule is present in fresh isolates of some species (except Moraxella catarrhalis). They are non-motile and non-sporing. Moraxella bovis contains numerous type IV fimbriae on its surface.

2.   Moraxella is aerobic, fastidious and non-fermenting in nature. However, some strains prefer anaerobic condition for their growth.    

3.   Classification : The genus Moraxella belongs to the Moraxellaceae family. Previously it was known as Branhamella. Most of the species are commensal except a few, which have disease producing capabilities. Important species are M. bovis, M. ovis, M. catarrhalis, M. boevrei, M. canis, M. caprae, M. caviae, M. cuniculi, M. phenylpyruvica.

4. Resistance : Resistance to physical and chemical agents is not remarkable. They are susceptible to desiccation and do not survive long outside the host. The beta- lactam antibiotic resistance is observed among M. catarrhalis isolates from clinical cases. This resistance is associated with the production of beta-lactamase enzyme.

Lucke (1862) first described that the bluish green discolouration of surgical dressing is associated with the presence of small vibrio like organisms. Latter Gessard first isolated the organism as Pseudomonas in 1882.

Properties of Genus

1. Morphology : They are Gram negative straight or curved rod, motile by one or more polar flagella. Usually it is 1.5 µm in length and 0.5 µm in width. Longer filamentous forms are sometimes observed. The bacteria are non- acid fast, non- sporulating and uncapsulated. Pili on the bacterial surface are detected. Environmental and strains present within tissue can produce slime. The slime is composed of glycolipoprotein (GLP) and polysaccharide of LPS.
    
2. They are strict aerobe.

Classification : Pseudomonas belongs to class Gamma-Proteobacteria, order- Pseudomonadales, family- Pseudomonadaceae.  Previously Pseudomonas included two group of bacteria viz. Fluorescent group and Pseudomallei group. Recent classification system included this Pseudomallei group into a new genus known as Burkholderia. Important species of Pseudomonas are:

Pasteurella and Mannheimia species are gram negative small coccobacilli under family Pasteurellaceae. Trevisan (1887) coined the generic name Pasteurella for the first time and it was accepted worldwide. Lignieres (1900) proposed the specific name for each organism according to the species of animal host: Pasteurella aviseptica for fowls; P. suiseptica for pigs; P. boviseptica for bovines; P. oviseptica for ovines and P. leptiseptica for rabbits. Finally, Rosenbuch and Merchant (1939) proposed a single species Pasteurella multocida and it is in use till date. 

      Mannheimia haemolytica was earlier known as Pasteurella haemolytica, but because of variations in cultural, pathological and 16S rRNA sequence, it is placed in separate genus.

Properties of genus

Morphology : P. multocida is a non motile, non spore-forming short rod or coccobacillus, 0.2-0.4 by 0.6-2.5 µm in size. Repeated laboratory subcultures or cultures grown under unfavourable conditions tend to be pleomorphic and longer rods or filamentous forms appear. In tissues, exudates and recently isolated cultures, the organism shows the typical coccobacillary forms. It is a gram-negative organism and, in fresh cultures and animal tissues, gives typical bipolar staining (Fig.1), particularly with Leishman or methylene blue stain.

Clinical conditions similar to Brucellosis have been described since the time of Hippocrates (450 BC). J. A. Marston first described brucellosis as gastric remittent fever in 1861 at Malta (Marston, 1861). Sir David Bruce in 1886 first isolated little coccobacillus from an infected soldier’s spleen. However he isolated the bacteria in a pure culture in 1887 and named Micrococcus melitensis (Bruce, 1889). Later the genus was renamed as Brucella in his honour. Similarly, Bang and Stribolg first isolated Brucella abortus from abortion material of a cow (Bang, 1897). Traum in 1914 isolated the Bacillus abortus suis. Presently we know it as Brucella suis. In 1953, Brucella ovis was first isolated in New Zealand (Budlle and Boyes, 1953) from the aborted material of sheep. Carmichael and Bruner in 1968 first isolated B. canis from the aborted placenta of a dog.

            In India first report of ‘Contagious abortion’ by Brucella was found from annual report of Imperial Veterinary Research Institute (presently Indian Veterinary Research Institute), Mukteswar, Uttarakhand (Anonymous, 1918). Seroprevalence of Brucellosis is reported from various states of India afterward (Polding, 1942; Sethi et al., 1971 etc.).

In 1886, Escherich observed Campylobacter like organisms in stool samples of children with diarrhoea. In 1913, McFaydean and Stockman first confirmed them as Campylobacter in foetal tissues of aborted sheep. Confirmatory tests were also carried out by Smith in 1918 when similar organisms were isolated from aborted bovine foetuses. The organism was then known as Vibrio foetus. In 1963, due to certain differentiating characteristics, the organisms were separated from Vibrionaceae family and the new genus Campylobacter (means ‘curved rod’) under Campylobacteriaceae family was proposed. 

Properties of genus

1.   Morphology :  Campylobacter is gram negative, comma shaped rods specially in infected tissues and young cultures. The size is 1.5-4 µm by 0.5 µm. When two bacterial cells are found together in a microscopic field, it looks like ‘S’ or ‘wing of gull’ (‘flying seagull’). However in older cultures, the chains of organism appear as long spirals. They are motile by single unipolar/ bipolar unsheathed flagella. Motility is darting or corkscrew type, best observed by dark field microscopy. They are non-sporing. Some species contains S-layer (surface layer), a paracrystalline protein structure composed of S-layer proteins (SLPs). It is external to the outer membrane. It helps the bacteria in immune evasion.