SOP: Determination of Setting Time and Temperature of High Methoxyl Pectin
GIFSQ — Global Institute for Food Safety & Quality Principle Setting time is the interval of time which elapses between the instant at which all the constituents of a jelly batch (sugar, pectin and acid) are filled into cans or bottles after cooking and the instant at which jellification or gelation of the whole into […]
SOP: Grading of Low-Methoxyl Pectin
GIFSQ — Global Institute for Food Safety & Quality Principle The jelly strength of low-methoxyl pectin is influenced not only by its pectin content and pH, but also by the calcium-to-pectin ratio, which depends on the manner of preparation of the low-methoxyl pectin and on its methoxyl content. Grading is carried out in gels with […]
SOP: Measurement of Jelly Strength by the Cox–Higby Sag Method
GIFSQ — Global Institute for Food Safety & Quality Principle The method measures the percentage sag or slump occurring when a test jelly is removed from its supporting container and inverted upon a glass plate. The apparatus is based on the ridgelimeter principle developed by Lockwood and Hayes for determining the strength of gelatine and […]
SOP: Measurement of Jelly Strength with the Lüers–Lochmüller Pektinometer
GIFSQ — Global Institute for Food Safety & Quality Principle The jelly is allowed to set in a special container with corrugated sides, and the force required to pull a disc embedded in the jelly upward is measured. The disc is suspended from one arm of a balance; a moving load on the other arm […]
SOP: Measurement of Jelly Strength by Sucharipa’s Jelly Disc Method
GIFSQ — Global Institute for Food Safety & Quality Principle The method measures the breaking strength of jellies at the point where they rupture after exceeding their elastic limit. Air pressure is built up against a set jelly disc until the jelly breaks; the breaking pressure is a measure of jelly strength. A second simultaneous […]
SOP: Determination of Jelly Grade with the Jelmeter
GIFSQ — Global Institute for Food Safety & Quality Principle Although sugars, proteins and starches influence the viscosity of fruit juices and extracts to a slight extent, the main influence on the viscosity is due to pectin. The viscosity of the extract is an indication of the quality and the quantity of pectin present and […]
SOP: Grading of Pectin by the Test Jelly Method
GIFSQ — Global Institute for Food Safety & Quality Principle The “grade” of pectin means the weight of sugar with which one part by weight of pectin will, under suitable conditions, form a satisfactory jelly. This jelly, subjected to the usual finger testing, should have the proper texture, resilience and consistency. For determining the grade […]
SOP: Determination of Pectin by the Optical Rotation Method
GIFSQ — Global Institute for Food Safety & Quality Principle The rotation of polarized light by pectin solutions is a characteristic property which can be used to determine pectin when the specific rotation is known. Apparatus required Polarimeter or saccharimeter (Bates-Jackson scale) 2-dm tube 1-dm tube Reagents a. Copper sulphate solution: dissolve 9.4 g of […]
SOP: Colorimetric Estimation of Pectic Substances
GIFSQ — Global Institute for Food Safety & Quality Principle Galacturonic acid, the basic structural unit of the pectin molecule, reacts with carbazole in the presence of H₂SO₄ to give a colour that is measured at 525 nm. Depending on the standard used, results may be expressed as anhydrogalacturonic acid (AuA), pectic acid, or in […]
SOP: Estimation of Pectin as Calcium Pectate
GIFSQ — Global Institute for Food Safety & Quality Principle Pectin extracted from plant material is saponified with alkali and then precipitated as calcium pectate from an acid solution by adding calcium chloride. The calcium pectate precipitate is washed until free from chloride, dried and weighed. Apparatus required 1000-ml beakers 500-ml volumetric flasks 500-ml conical […]
SOP: Determination of Molecular Weight of Pectin
GIFSQ — Global Institute for Food Safety & Quality Principle The molecular weight of pectin is determined viscometrically by the Smit and Bryant method. The relative viscosity of a pectin solution in 1% sodium hexametaphosphate is measured against the solvent in an Ostwald-Cannon-Fenske viscometer, and the molecular weight is calculated from the relative viscosity, the […]
SOP: Determination of Number Average Molecular Weight of Pectin
GIFSQ — Global Institute for Food Safety & Quality Principle The number average molecular weight is an important factor controlling jellying with pectin. Direct measurement of osmotic pressure is preferred over converting the pectin into the nitrate, because direct measurement reduces the chance of degradation and of fractionation. The method uses the Bull osmometer, slightly […]
SOP: Determination of Intrinsic Viscosity of Pectin
GIFSQ — Global Institute for Food Safety & Quality Principle The contribution that pectin makes to the viscosity of food products, to the firmness of texture, and to jelly formation is due in part to its molecular weight. The simplest measure of viscosity average molecular weight is the intrinsic viscosity: the limiting value for the […]
SOP: Determination of Acetyl Value of Pectin
GIFSQ — Global Institute for Food Safety & Quality Principle Sugar-beet pectin carries an acetyl group, and other pectins may carry it too. When the acetyl group is present in pectin, it inhibits jelly formation. Analysis of this functional group by simple alkaline saponification followed by back titration does not give satisfactory results, so the […]
SOP: Estimation of Anhydrouronic Acid in Pectin
GIFSQ — Global Institute for Food Safety & Quality Principle Pectin is a partly esterified polygalacturonide; it contains 10% or more of organic material composed of arabinose, galactose and perhaps other sugars. The anhydrouronic acid content is calculated from the equivalent weight, the methoxyl content and the alkalinity-of-ash data. Its estimation is essential for determining […]
SOP: Determination of Methoxyl Content of Pectin
GIFSQ — Global Institute for Food Safety & Quality Principle The methoxyl content, which expresses the degree of esterification, is found by saponifying the pectin and titrating the liberated carboxyl groups. It is an important factor in controlling the setting time of pectins, their sensitivity to polyvalent cations, and their usefulness in the preparation of […]
SOP: Determination of Equivalent Weight of Pectin
GIFSQ — Global Institute for Food Safety & Quality Principle The equivalent weight is used for calculating the anhydrouronic acid content and the degree of esterification. It is found by titrating the free carboxyl groups of the pectin with standard sodium hydroxide solution to pH 7.5, using either phenol red or Hinton’s indicator. Apparatus required […]
SOP: Determination of Ash in Pectin
GIFSQ — Global Institute for Food Safety & Quality Principle The pectic substance is ignited slowly and then heated at 600°C to obtain the ash gravimetrically. The alkalinity of the ash is found by dissolving it in standard hydrochloric acid and titrating with standard sodium hydroxide; the carbonate-free ash is then obtained by subtracting the […]
SOP: Determination of Moisture in Pectin
GIFSQ — Global Institute for Food Safety & Quality Principle The pectin sample is dried in vacuo at 100°C; the loss in weight gives the moisture content. Because drying at 100°C degrades the pectin, samples intended for further measurements are dried under milder conditions instead. Apparatus required Tared metal dish (5 cm in diameter, with […]
SOP: Extraction and Purification of Pectin
GIFSQ — Global Institute for Food Safety & Quality Principle Pectin is extracted from the prepared plant tissue by heating with water containing sodium hexametaphosphate at pH 4.5. After filtration, the extract is concentrated in vacuo if the pectin level is low, and the pectin is precipitated with acidified alcohol or acetone. The precipitate is […]
SOP: Determination of Starch by the Enzymic Method
GIFSQ — Global Institute for Food Safety & Quality Principle The method is suitable for products containing natural starch. Sugars are removed by leaching with alcohol. If much fat and proteinaceous material is present, the sample is treated with hot ethanolic-KOH and washed with 80% ethanol. The starch in the residue is gelatinized and incubated […]
SOP: Determination of Starch by the Colorimetric (Anthrone) Method
GIFSQ — Global Institute for Food Safety & Quality Principle After the free sugars are extracted with hot alcohol, the starch is solubilized with 52% perchloric acid and determined colorimetrically with anthrone reagent at 630 nm against a dextrose standard curve. Apparatus required 50-ml centrifuge cups and centrifuge Ice water bath 100-ml volumetric flasks Boiling […]
SOP: Determination of Starch by the Acid Hydrolysis Method
GIFSQ — Global Institute for Food Safety & Quality Principle After the sugars present in the sample are leached out with alcohol, the starch is hydrolysed with acid and estimated as invert (reducing) sugars. Apparatus required Centrifuge 500-ml conical flask Boiling water bath Test tubes (for the sugar test) Centrifuge — GIFSQ illustration Reagents a. […]
SOP: Determination of Crude Fibre
GIFSQ — Global Institute for Food Safety & Quality Principle Crude fibre is the organic residue which remains after the food sample has been treated under standardized conditions with petroleum spirit, boiling dilute sulphuric acid, boiling dilute sodium hydroxide solution and alcohol. The crude fibre consists largely of cellulose together with a little lignin. As […]
SOP: Determination of Nitrogen by the Macro-Kjeldahl Method
GIFSQ — Global Institute for Food Safety & Quality Principle As in the micro-Kjeldahl method: the nitrogenous compounds of the sample are converted into ammonium sulphate by boiling with concentrated sulphuric acid; the ammonium sulphate is decomposed with alkali, and the liberated ammonia is distilled into boric acid solution and titrated with standard acid. Apparatus […]
SOP: Determination of Nitrogen by the Micro-Kjeldahl Method
GIFSQ — Global Institute for Food Safety & Quality Principle The nitrogen content is estimated by the Kjeldahl method, which is based on the determination of the amount of reduced nitrogen (NH₃ and NH₄) present in the sample. The various nitrogenous compounds are converted into ammonium sulphate by boiling with conc. H₂SO₄. The ammonium sulphate […]
SOP: Determination of Total Reducing Sugars and Fructose by the Rapid Colorimetric Method
GIFSQ — Global Institute for Food Safety & Quality Principle Ferricyanide is used in a carbonate-phosphate buffer as the oxidizing agent for sugars. The ferrocyanide produced is measured colorimetrically using the blue solution formed after the addition of Nelson’s arsenomolybdate reagent. When heated at 100°C for 10 min, glucose and fructose are oxidized in equal […]
SOP: Determination of Sugars by the Shaffer-Somogyi Micro Method
GIFSQ — Global Institute for Food Safety & Quality Principle Reducing sugars in pure solutions — or in plant materials after suitable pre-treatment to remove interfering substances — are estimated with a copper reagent of the type that uses iodometric titration of the cuprous oxide formed. This method can be used to determine the sugar […]
SOP: Determination of Sugars by the Lane and Eynon Method
GIFSQ — Global Institute for Food Safety & Quality Principle Invert sugar reduces the copper in Fehling’s solution to red, insoluble cuprous oxide. The sugar content of a food sample is estimated by determining the volume of the unknown sugar solution required to completely reduce a measured volume of Fehling’s solution. Apparatus required 250-ml conical […]
SOP: Determination of Crude Fat (Ether Extractives) by the Soxhlet Method
GIFSQ — Global Institute for Food Safety & Quality Principle The ether-soluble material is extracted from an oven-dried sample in a Soxhlet extraction apparatus; the ether is then evaporated and the residue weighed. Besides the true fat (triglycerides), the crude fat includes phospholipids, sterols, essential oils, fat-soluble pigments and other materials extractable with ether. Water-soluble […]
SOP: Determination of Titrable Acidity
GIFSQ — Global Institute for Food Safety & Quality Principle The acidity of the prepared sample solution is determined by titrating an aliquot with standard sodium hydroxide solution, using phenolphthalein as indicator. The result is calculated as per cent anhydrous citric acid (or as per cent of the other acid reported). Apparatus required Blender or […]
SOP: Determination of Sulphated Ash
GIFSQ — Global Institute for Food Safety & Quality Principle In samples where complete combustion is difficult to achieve, or where constituents may be lost by volatilization on ignition, the ash is moistened with concentrated sulphuric acid and ignited gently to constant weight. The residue obtained is the sulphated ash. Apparatus required Silica dish containing […]
SOP: Determination of Alkalinity of Ash
GIFSQ — Global Institute for Food Safety & Quality Principle The ash is treated with a measured excess of standard acid, and the excess acid is back-titrated with standard alkali using methyl orange indicator. The alkalinity, expressed as potassium carbonate, is calculated from the acid consumed. The same titration is applied to the ash as […]
SOP: Determination of Acid-Insoluble Ash
GIFSQ — Global Institute for Food Safety & Quality Principle The ash of the sample is boiled with dilute hydrochloric acid. The material that remains insoluble — mainly sand and other siliceous matter — is filtered off, washed free of acid, ignited, and weighed. The acid-insoluble ash is a measure of the sand and siliceous […]
SOP: Determination of Water-Soluble and Water-Insoluble Ash
GIFSQ — Global Institute for Food Safety & Quality Principle The total ash is separated into a water-soluble and a water-insoluble fraction by boiling the ash with water. The residue retained on the filter after washing with hot water, ignited in the original dish, is the water-insoluble ash; the water-soluble ash is obtained by subtracting […]
SOP: Determination of Total Ash
GIFSQ — Global Institute for Food Safety & Quality Principle Ash is the inorganic residue remaining after the destruction of organic matter by ignition. It may not be exactly equivalent to the mineral matter of the food, because some constituents may be lost by volatilization or may interact during ignition. A high ash content, or […]
SOP: Determination of Moisture by Rapid Physical and Chemical Methods (Overview)
GIFSQ — Global Institute for Food Safety & Quality Principle Besides oven drying and immiscible solvent distillation, moisture may be determined by rapid physical methods, which measure a physical property of the water in the food, and by rapid chemical methods, which measure water through a chemical reaction. This procedure summarizes the rapid methods described […]
SOP: Determination of Moisture by Immiscible Solvent Distillation (Bidwell-Sterling)
GIFSQ — Global Institute for Food Safety & Quality Principle Moisture is determined by reflux distillation of the food with an immiscible solvent that has a higher boiling point and a lower specific gravity than water (for example toluene, heptane or xylene). The distilled water settles in the graduated collecting tube while the solvent floats, […]
SOP: Determination of Moisture by Drying in a Vacuum Oven
GIFSQ — Global Institute for Food Safety & Quality Principle Moisture is determined gravimetrically by drying the sample in a vacuum oven at 70°C under reduced pressure. The reduced pressure lowers the effective drying temperature and is preferred where decomposition is likely, as in fruit products containing an appreciable proportion of sugars. Dry air is […]
SOP: Determination of Moisture by Oven Drying
GIFSQ — Global Institute for Food Safety & Quality Principle Moisture is determined gravimetrically by measuring the weight lost by the food on evaporation of water in a hot-air oven at atmospheric pressure. The loss in weight may not be a true measure of the water content of the sample, because some volatile constituents may […]
SOP: Determination of Acid Insoluble Ash — Spices
GIFSQ — Global Institute for Food Safety & Quality 1. Principle The acid insoluble ash is a measure of sand and other siliceous matter present in the sample. When ash is dissolved in dilute acid, inorganic compounds dissolved in acid, leaving silica and sand as acid insoluble ash. 2. Application This method is applicable to […]
SOP: Water Soluble Matter Other than Sodium Chloride (in Salt)
GIFSQ — Global Institute for Food Safety & Quality Principle Determination of water-soluble matter other than sodium chloride is done after determination of the parameters sodium chloride percentage and water insoluble matter percentage on the dry basis. Calculation % water soluble matter other than sodium chloride = 100 − (NaCl % + % water insoluble […]
SOP: Determination of Salt Content in Spices
GIFSQ — Global Institute for Food Safety & Quality Introduction PFA Act 1954 and PFA Rule 1955 define salt as NaCl and nothing else, which is determined volumetrically by titrating the salt containing extract with silver nitrate, employing potassium chromate as indicator. Spice commodities generally contain 0.61% salt in terms of NaCl. Estimation of salt […]
SOP: Detection of Mineral Oil in Black Pepper
GIFSQ — Global Institute for Food Safety & Quality Procedure Take about 10 g sample in a 100 mL glass stoppered conical flask and add 25 mL petroleum ether ↓ Shake well for 30 seconds and immediately filter in a 50 mL beaker ↓ Evaporate the solvent in the beaker on a water bath. Dissolve […]
SOP: Determination of Total Ash Content — Tea and Coffee
GIFSQ — Global Institute for Food Safety & Quality The ash of a foodstuff is the inorganic residue remaining after complete burning away of the food, usually at a temperature not exceeding red heat. Ash can often serve as a measure for adulteration of a food. The higher the ash content of the sample, the […]
SOP: Determination of Water Insoluble Impurities in Salt
GIFSQ — Global Institute for Food Safety & Quality 1. Principle The water insoluble fraction is separated by dissolving sample in distilled water followed by filtration. Thus obtained residue is expressed in percentage as a water insoluble impurity. 2. Application This method is applicable to spices and other food products. 3. Apparatus Filter paper, Petri […]
SOP: Determination of Iodine Content in Iodized Salt
GIFSQ — Global Institute for Food Safety & Quality Salt is iodized by using compound potassium iodate (KIO₃), so that iodine in a salt corresponds to the iodine in a potassium iodate. 1. Application This method is applicable for determination of iodine content in powdered salt as well as Dhikke (large crystallized) salt. 2. Apparatus […]
SOP: Determination of Sodium Chloride Content in Salt
GIFSQ — Global Institute for Food Safety & Quality 1. Principle Chloride is estimated in a sample solution by titrating with standard silver nitrate solution, using potassium chromate as indicator, and is expressed as sodium chloride. 2. Application This method is applicable to estimate the sodium chloride percentage where chloride is present as sodium chloride. […]
SOP: Determination of Moisture in Salt
GIFSQ — Global Institute for Food Safety & Quality 1. Principle The sample is dried to a constant weight at 250 ± 5°C and loss in weight is reported as moisture content. 2. Application This method is applicable for determining moisture in sample having mineral origin, i.e. stable towards temperature. 3. Apparatus Erlenmeyer flask, small […]
SOP: Determination of MSG in Foods by HPLC-UV
GIFSQ — Global Institute for Food Safety & Quality (The manual numbers both the salt method and this method 2.3.17.) 1. Scope The method is applied to all types of noodles and MSG containing foods including seasonings. 2. Definition This method determines the concentration of Monosodium Glutamate (MSG). The result is usually expressed in percentage. […]
SOP: Determination of Starch Content — Spices
GIFSQ — Global Institute for Food Safety & Quality Reagents Ethyl ether Ethyl alcohol 10% (v/v) Dilute hydrochloric acid — 2.5%, prepared by mixing 20 mL of conc. HCl (sp. gr. 1.12) with 200 mL water Sodium carbonate solution — 20% (w/v) Procedure Extract about 3 g of the ground sample, accurately weighed, with five […]
SOP: Determination of Cold Water Soluble Extract — Spices
GIFSQ — Global Institute for Food Safety & Quality Procedure Weigh to the nearest 0.001 g about 2 g sample, transfer to a 100 mL volumetric flask, add distilled water and make up to mark ↓ Stopper the flask and shake at approximately 30 minutes interval for 8 hours, and allow to stand for 16 […]
SOP: Determination of Crude Fiber — Spices
GIFSQ — Global Institute for Food Safety & Quality 1. Principle When defatted spices are treated with boiling dilute sulphuric acid and boiling dilute sodium hydroxide, the remaining organic residue is determined as crude fiber. 2. Application This method is applicable to all type of food and food products. 3. Reagents Dilute sulphuric acid — […]
SOP: Determination of Steam Volatile Oil (Essential Oil) — Lee and Ogg Method
GIFSQ — Global Institute for Food Safety & Quality 1. Principle Test portion is boiled in H₂O or NaCl solution. Released volatile oil (vapor form) is condensed and collected in trap, and then measured through trap calibration. 2. Application This method is applicable to determine the amount of volatile oil of spices. 3. Apparatus Flask, […]
SOP: Determination of Total Ash — Spices
GIFSQ — Global Institute for Food Safety & Quality The ash of a foodstuff is the inorganic residue remaining after complete burning away of the food, usually at a temperature not exceeding red heat. Ash can often serve as a measure for adulteration of a food. The higher the ash content of the sample, the […]
SOP: Determination of Moisture in Spices — Dean and Stark Toluene Distillation Method
GIFSQ — Global Institute for Food Safety & Quality 1. Principle Moisture in spices is determined by the Dean and Stark entrainment method (toluene distillation method). Toluene is added to the sample in a flask and heated to boiling. The water and toluene boil off as an azeotropic mixture. Upon cooling, water and toluene separate […]
SOP: Lead Chromate Test — Turmeric and Spices
GIFSQ — Global Institute for Food Safety & Quality Because of similarities of the lead chromate with turmeric powder in color and solubility in water, it may be employed as adulterant to uplift faded color of rhizomes and also to patch up black moldy patches on them. Turmeric used as an ingredient in the manufacture […]
SOP: Detection of Argemone Seeds in Mustard
GIFSQ — Global Institute for Food Safety & Quality Procedure Weigh 50 g of powdered sample sufficient to yield 5–10 g nonvolatile ether extract ↓ Extract with 125 mL ethyl ether in a closed Erlenmeyer flask for 24 hrs with occasional shaking ↓ Filter the contents through Whatman filter paper No. 1 and wash the […]
SOP: Determination of Curcumin in Turmeric (Spices)
GIFSQ — Global Institute for Food Safety & Quality 1. Principle Curcumin is extracted by refluxing the sample with the alcohol for about 3 hours. After dilution, concentration of curcumin is measured by spectrophotometer at 425 nm against the alcohol blank. 2. Application This method is applicable to determine curcumin in spices. 3. Apparatus Flask, […]
SOP: Determination of Alcohol Soluble Extract — Spices
GIFSQ — Global Institute for Food Safety & Quality 1. Principle Sample is extracted with ethanol and evaporated to dryness. It is heated in the oven at 103 ± 2°C; the remaining residue is alcohol soluble matter. 2. Application This method is applicable to determine the amount of alcohol soluble material in spices under specified […]
SOP: Analysis of Soluble Instant Coffee
GIFSQ — Global Institute for Food Safety & Quality Methods by reference Moisture — see the determination of moisture content in tea and coffee Total Ash — see the determination of total ash in tea and coffee Caffeine — see the determination of caffeine in tea and coffee 1.6.4 Solubility in boiling water Weigh 2.5 […]
SOP: Analysis of Roasted and Ground Coffee — Sample Preparation and Method References
GIFSQ — Global Institute for Food Safety & Quality 1.5.1 Preparation of sample for ground coffee Grind the sample in a grinder to pass through No. 30 mesh sieve. Mix well to get homogeneous sample. Store sample in a tightly stoppered bottle. Withdraw portion for analytical determinations. Reference: AOAC, 920.91 (sample preparation of coffee). Methods […]
SOP: Determination of Non-Volatile Ether Extract (Fixed Oil) — Spices
GIFSQ — Global Institute for Food Safety & Quality 1. Principle The spice sample is extracted with petroleum ether, the ether is distilled off and the non-volatile residue is weighed as non-volatile ether extract. 2. Application This method is applicable to estimate fixed oil in spices having low volatile oil percentage, as well as in […]
SOP: Determination of Crude Fibre — Tea and Coffee
GIFSQ — Global Institute for Food Safety & Quality 1. Principle Crude fibre is defined as the sum of all those organic components of the plant cell membrane and supporting structures that remain after the removal of protein, fat, starch and water soluble components. Thus, crude fiber is composed of cellulose, hemicellulose, lignin and pectic […]
SOP: Determination of Caffeine in Tea and Coffee by HPLC
GIFSQ — Global Institute for Food Safety & Quality 1. Principle Caffeine is determined in a clear, filtered, extracted solution of tea/coffee (extracted in hot water) by using reverse phase HPLC equipped with UV detector. The signal of sample is compared with those from standard caffeine solutions for identification, confirmation and quantification. 2. Application The […]
SOP: Determination of Water Extract — Tea and Coffee
GIFSQ — Global Institute for Food Safety & Quality 1. Principle Water soluble substance in tea can be conveniently determined by extracting the dry sample with distilled water. Tea sample is refluxed for one hour, where the water soluble fraction is extracted quantitatively. 2. Application This method is applicable for all types of tea and […]
SOP: Determination of Alkalinity of Ash (Water Soluble Ash) — Tea
GIFSQ — Global Institute for Food Safety & Quality 1. Principle The total filtrate obtained in the course of the water soluble ash determination process is titrated against 0.1 N HCl using methyl orange as an indicator. The alkalinity of soluble ash is calculated as K₂O on the basis of the reaction given below: K₂O […]
SOP: Determination of Water Soluble Ash — Tea and Coffee
GIFSQ — Global Institute for Food Safety & Quality 1. Principle The total ash obtained is boiled with distilled water and filtered hot through an ashless filter paper (No. 42 or equivalent). The residue is washed with hot water until it is free from alkali. The filter paper along with residue is ignited in the […]
SOP: Determination of Acid Insoluble Ash — Tea and Coffee
GIFSQ — Global Institute for Food Safety & Quality 1. Principle The ash obtained in the process of water soluble ash determination is treated with (1:2.5) HCl and water. The warm solution is filtered through ashless filter paper (No. 42 or Equivalent). The residue is washed with hot distilled water until free from acid, and […]
SOP: Determination of Moisture Content in Tea and Coffee
GIFSQ — Global Institute for Food Safety & Quality 1. Principle Moisture in tea is determined by the Hot Air Oven method. The sample is heated under carefully specified conditions and the loss of weight is taken as a measure of the moisture content of the sample. 2. Application This method is applicable for determining […]
SOP: Determination of Salt Content in Butter by Mohr’s Method
GIFSQ — Global Institute for Food Safety & Quality 1. Principle In this method, the butter sample is melted in hot water, and the chlorides present in the mixture are titrated with a solution of silver nitrate using potassium chromate as indicator. Reaction AgNO₃ + NaCl → AgCl + NaNO₃ 2AgNO₃ + K₂CrO₄ → Ag₂CrO₄ […]
SOP: Determination of Total Ash Content in Milk Powder
GIFSQ — Global Institute for Food Safety & Quality Scope This method is applicable to all dairy products. 1. Principle When milk powder is ignited at high temperature in a muffle furnace, organic matter is burnt out and mineral and other inorganic matter remains in the ash. 2. Apparatus a. Platinum or silica crucible: about […]
SOP: Milk Powder — Preparation of Sample and Determination of Moisture
GIFSQ — Global Institute for Food Safety & Quality Scope Whole milk powder, skimmed milk powder, partially skimmed milk powder, infant milk food, infant formula, milk cereal weaning food and processed cereal based weaning food fall under this category. 1. Preparation of sample of milk powder Make the sample homogeneous either by mixing or shaking, […]
SOP: Paneer — Preparation of Sample, Moisture and Fat
GIFSQ — Global Institute for Food Safety & Quality 1. Preparation of sample of paneer Grate the paneer sample quickly through a suitable grater. Mix the grated sample thoroughly. Transfer the grated sample to an air-tight container to await analysis, which should be carried as soon as possible after grinding. Keep the sample in an […]
SOP: Determination of Fat Content in Cheese (Gerber)
GIFSQ — Global Institute for Food Safety & Quality Scope This method is applicable to all varieties of cheese. 1. Principle The fat in cheese is in the form of an emulsion. This emulsion is broken with sulphuric acid and fat separation is facilitated by amyl alcohol. 2. Apparatus a. Gerber centrifuge b. Gerber cheese […]
SOP: Cheese — Preparation of Sample and Determination of Moisture
GIFSQ — Global Institute for Food Safety & Quality 1. Preparation of sample of cheese Prior to analysis, remove the rind or smear or mouldy surface layer of the cheese, in such a way as to provide a sample representative of the cheese as it is usually consumed. Grind or grate the sample by means […]
SOP: Test for the Presence of Vanaspati Ghee in Butter (Baudouin Test)
GIFSQ — Global Institute for Food Safety & Quality Scope This method is applicable for testing the presence of vanaspati ghee in butter and ghee. 1. Principle The development of a permanent pink colour in a sample of butter with furfural solution in the presence of hydrochloric acid indicates the presence of sesame oil, and […]
SOP: Qualitative Method for Colour Additives in Butter
GIFSQ — Global Institute for Food Safety & Quality 1. Principle Several dyes and colours like azo-dyes, annatto or other vegetable colour, and gallate antioxidants in butter give characteristic colour upon treatment with alkali or acid. 2. Apparatus a. Balance b. Test tubes c. Pipettes Qualitative test tubes — GIFSQ illustration 3. Chemicals a. Ethyl […]
SOP: Determination of Fat Content in Butter (Gerber)
GIFSQ — Global Institute for Food Safety & Quality 1. Principle When sulphuric acid is added to butter, the proteins will be digested, thus destroying the membrane of the fat globules. The free fat is then released. The fat remains in liquid due to heat produced, and during centrifugation the fat, being lighter, will be […]
SOP: Butter — Preparation of Sample and Determination of Moisture
GIFSQ — Global Institute for Food Safety & Quality 1. Preparation of sample of butter Warm the sample in an airtight container with the lid screwed down tightly, or with the glass stopper, in an oven or water bath maintained at 37 ± 2°C. Shake vigorously to obtain a homogeneous fluid emulsion free from un-softened […]
SOP: Ice Cream — Preparation of Sample, Protein, Fat and Colour Additives
GIFSQ — Global Institute for Food Safety & Quality 1. Preparation of sample In order to keep the sample homogeneous, it is better to allow it to melt at room temperature rather than to heat it. Mix thoroughly by stirring or by pouring bulk and further one vessel to another. If the sample contains milk […]
SOP: Determination of Protein Content in Milk Powder (Kjeldahl)
GIFSQ — Global Institute for Food Safety & Quality Scope This method is applicable to milk and milk products. 1. Principle Protein in milk and milk products is digested with concentrated sulphuric acid in the presence of a catalyst containing a mixture of sodium or potassium sulphate and copper sulphate, in a digestion chamber. During […]
SOP: Determination of Fat in Milk Powder by Röse-Gottlieb Method
GIFSQ — Global Institute for Food Safety & Quality 1. Principle The sample is treated with ammonia and ethyl alcohol; the former to dissolve the protein and the latter to help precipitate the proteins. Fat is extracted with diethyl ether and petroleum ether. Mixed ethers are evaporated and the residue weighed. This method is considered […]
SOP: Determination of Fat in Milk Powder by Gerber Method (Routine Method)
GIFSQ — Global Institute for Food Safety & Quality Scope This method is applicable to all types of milk powders. 1. Principle The Gerber method for determination of fat in milk and milk products depends on the liberation of the fat by the action of sulphuric acid on milk or milk products in specifically shaped, […]
SOP: Determination of Sugar Content in Condensed Milk
GIFSQ — Global Institute for Food Safety & Quality Scope This method is applied to milk and milk products. 1. Principle The principle involves clarifying the sample with the help of zinc acetate and potassium ferrocyanide, inverting a part of the sample using hydrochloric acid, and determining the reducing sugars content in both inverted and […]
SOP: Determination of Fat Content in Condensed Milk (Gerber)
GIFSQ — Global Institute for Food Safety & Quality Scope This method is applicable to all dairy products and food and food products such as sweetened condensed milk, skim condensed milk as well as other food products. 1. Principle When sulfuric acid is added to the milk, the protein will be digested, thus destroying the […]
SOP: Condensed Milk — Preparation of Sample and Determination of Total Solids
GIFSQ — Global Institute for Food Safety & Quality 1. Preparation of sample Temper the unopened can in a water bath at 30–35°C until warm ↓ Open, transfer to a beaker large enough to permit stirring thoroughly, scrape out all milk adhering to the interior of the can, and mix until the whole mass is […]
SOP: Test for Presence of Formalin in Milk (Chromotropic Acid Test)
GIFSQ — Global Institute for Food Safety & Quality 1. Reagents Chromotropic acid reagent: prepare a saturated solution of 1,8-dihydroxynaphthalene-3,6-disulfonic acid by stirring 0.5 g of the acid in 100 mL of 72% H₂SO₄. The solution is pale yellow in color. Prepare 72% H₂SO₄ by taking 150 mL of concentrated H₂SO₄ and mixing with 100 […]
SOP: Determination of Total Solids in Dahi (Sodium Hydroxide Method)
GIFSQ — Global Institute for Food Safety & Quality 1. Principle In cultured dairy products such as dahi or yoghurt, total solids are determined after neutralization of developed acidity with alkali. In this procedure, NaOH is used for neutralization of developed acidity, followed by determination of total solids by evaporation at 100 ± 2°C. 2. […]
SOP: Preparation of Dahi Sample and Determination of Fat in Dahi (Gerber)
GIFSQ — Global Institute for Food Safety & Quality 1. Preparation of sample of Dahi To get a representative sample, particularly in case of a thick-set product, it may be necessary to pour out the whole of the contents in a mortar and mix it thoroughly until the mass is homogeneous. Aliquots are weighed out […]
SOP: Determination of Acidity in Milk Powder
GIFSQ — Global Institute for Food Safety & Quality Scope This method is applicable to fluid milk, powder milk and other milk products. 1. Principle The method is based on the titration of the sample with sodium hydroxide to a phenolphthalein end point, and by comparing the colour with the colour obtained by mixing rosaniline […]
SOP: Determination of Acidity in Milk
GIFSQ — Global Institute for Food Safety & Quality 1. Principle The sample is titrated with sodium hydroxide to a phenolphthalein end point, using milk containing rosaniline as a comparison standard. 2. Apparatus a. 100 mL porcelain basin b. Burette Titration apparatus — GIFSQ illustration 3. Reagents a. 0.1 N NaOH solution b. Rosaniline acetate […]
SOP: Determination of Fat Content in Raw and Pasteurized Milk by Gerber Method
GIFSQ — Global Institute for Food Safety & Quality Scope This method prescribes the procedure for the determination of fat in whole milk, evaporated milk, and standardized milk, toned milk, double toned milk, separated milk, skimmed milk, buttermilk, condensed milk and homogenized milk by the Gerber method. Sampling and sample preparation If the sample is […]
SOP: Detection of Neutralizers in Milk (Rosalic Acid Method)
GIFSQ — Global Institute for Food Safety & Quality 1. Principle Neutralizers (NaOH, Na₂CO₃ and NaHCO₃) are added to milk to neutralize the developed acidity in milk. The rosalic acid method can be used for the detection of the presence of these neutralizers in milk. There are two variants of this method; both variants are […]
SOP: Detection of Sodium Chloride in Milk
GIFSQ — Global Institute for Food Safety & Quality 1. Principle The presence of extraneously added sodium chloride in milk can be detected by silver nitrate and potassium chromate reagent. 2. Reagents a. Silver nitrate (AgNO₃) solution: 0.1 N, aqueous b. Potassium chromate (K₂CrO₄) solution: 10% (w/v), aqueous 3. Procedure Take 5.0 mL of milk […]
SOP: Detection of Urea in Milk (Quantitative Method)
GIFSQ — Global Institute for Food Safety & Quality 1. Principle Urea is a natural constituent of milk and it forms a major part of the non-protein nitrogen of milk. Urea concentration in milk is variable within a herd. Urea content in natural milk varies from 20 mg/100 mL to 70 mg/100 mL. However, urea […]
SOP: Detection of Starch in Milk (Qualitative Method)
GIFSQ — Global Institute for Food Safety & Quality 1. Principle Starch molecules form a blue colored complex with iodine. Incorporation of starch in milk can be detected by adding iodine solution to it. 2. Reagents a. Iodine solution: dissolve 2.6 g of iodine and 3 g of potassium iodide in a sufficient quantity of […]
SOP: Detection of Cane Sugar in Milk (Modified Seliwanoff’s Method)
GIFSQ — Global Institute for Food Safety & Quality 1. Principle Fructose in cane sugar (sucrose) reacts with resorcinol in HCl to give red colour. 2. Reagents a. Resorcinol solution (0.5%): weigh 0.5 g of resorcinol in about 40 mL of distilled water. Add 35 mL of concentrated HCl (12 N) to it and make […]
SOP: Peroxide Value of Extracted Fat (Noodles and Fried Snacks)
GIFSQ — Global Institute for Food Safety & Quality Definition Peroxide value is the measure of the reactive oxygen content of a fat, expressed in terms of milliequivalents of oxygen per 1000 gram of fat, or as millimols of peroxide per kilogram of fat (1 millimol = 2 milliequivalents). The peroxide value provides an estimate […]
SOP: Acidity of Extracted Fat and Acid Value (Biscuits and Flour Confectionery)
GIFSQ — Global Institute for Food Safety & Quality Introduction The acid value is a measure of the extent to which the glycerides in the fat have been decomposed by lipase action. The decomposition is accelerated by light and heat and is accompanied by free fatty acid formation. As rancidity is often accompanied by free […]
SOP: Determination of Gluten in Flour
GIFSQ — Global Institute for Food Safety & Quality 1. Principle Gluten is the cohesiveness obtained by interaction of the water-insoluble proteins of wheat in the presence of water. Gluten is estimated by washing the dough, making it free from starch, sugar, water soluble proteins and other minor components. 2. Procedure Weigh 25 g flour […]
SOP: Determination of Total Solids in Bread
GIFSQ — Global Institute for Food Safety & Quality 1. Principle The part of bread other than water and included gas is called total solid. The total solid of bread is obtained from the method of drying. 2. Procedure a. All types of bread not containing fruit Accurately weigh about 5 g of bread immediately […]
SOP: Determination of Alcoholic Acidity
GIFSQ — Global Institute for Food Safety & Quality Definition Alcoholic acidity is defined as the mg of H₂SO₄ required for 100 g of the sample to have the same alcohol soluble acids. Grains or their milled products, on storage, undergo physical as well as chemical changes. Acid phosphates, amino acids and free fatty acids […]
SOP: Determination of Crude Protein (Kjeldahl Method)
GIFSQ — Global Institute for Food Safety & Quality 1. Principle The sample is digested in H₂SO₄, using CuSO₄ as catalyst, converting the protein nitrogen to (NH₄)₂SO₄. Ammonia is liberated by alkaline steam distillation, trapped in dilute boric acid and titrated with standardized acid to a colorimetric endpoint. 2. Apparatus a. Kjeldahl digestion set b. […]
SOP: Determination of Crude Fiber
GIFSQ — Global Institute for Food Safety & Quality 1. Principle Crude fiber is the loss on ignition of the dried residue remaining after digestion of the sample with 1.25% (w/v) H₂SO₄ and 1.25% (w/v) NaOH solutions under specified conditions. The method is applicable to materials from which the fat can be and is extracted […]
SOP: Determination of Moisture Content and Total Solids in Cereals and Pulses Flour
GIFSQ — Global Institute for Food Safety & Quality 1. Principle The sample is heated at a specified temperature for a specified time in a hot air oven, and the loss in weight is taken as a measure of the moisture content of the sample. Total solids are obtained by difference from the moisture content. […]
SOP: Determination of Crude Fat or Ether Extract
GIFSQ — Global Institute for Food Safety & Quality 1. Principle The solvent dissolves fats, oils, pigments and other soluble substances, collectively termed crude fat. The finely ground sample, held in a thimble, is extracted by a continuous flow of solvent; the solvent is evaporated and recovered by condensation, and the resulting crude fat residue […]
SOP: Determination of Acid Insoluble Ash (AIA)
GIFSQ — Global Institute for Food Safety & Quality 1. Principle Acid insoluble ash is a measure of the sandy particles and other siliceous matter present in flour. When the total ash obtained is treated with dilute acid, the inorganic compounds dissolve in the acid, leaving the siliceous and sandy matter as insoluble ash. The […]
SOP: Determination of Total Ash Content
GIFSQ — Global Institute for Food Safety & Quality 1. Principle Ash is the mineral residue that remains after complete incineration of a sample. A known quantity of sample is incinerated without flaming at a specified temperature until the residue is free from carbon. The residue is cooled in a desiccator, and the total ash […]
SOP: pH Measurement in Food Products
SOP: pH Measurement in Food Products pH measurement is one of the most routine tests in a food laboratory, and one of the easiest to get wrong. A poorly calibrated meter or a rushed reading can shift a result by several tenths — enough to change a shelf-life decision, a formulation adjustment, or a safety […]