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Garlic - Processing, properties and toxicity


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1 Introduction Garlic (Allium sativum L.) is the second most widely cultivated Allium after onion. According to FAO estimates for the year 1999, the world area cultivated is 889,000 ha and production is 8,776,000 mt. China, Korea, India, USA, Spain, Argentina and Egypt are the major garlic growing countries. China ranks first in area (424,000 ha) and production (5,690,000 mt) followed by India in area (113,000 ha) and Korea in production (484,000 mt) (Table 1). In productivity, Egypt tops the list (25,366 kg/ha) followed by USA (16,250 kg/ha), China (13,421 kg/ha) and Korea Republic (11,916 kg/ ha). Korea Republic has the highest per capita availability, i.e. 10.50 kg per year followed by Argentina (5.01 kg) and China (4.53 kg). The world garlic area, production and productivity trends during the past decade show that since 1986 they have improved by about 115.78%, 245.92% and 60.41%, respectively (Table 2). Garlic is in demand almost all the year round all over the world both in fresh form and also in dehydrated form. Today, garlic is used for its flavour, aroma and taste being prepared domestically or forming a raw material for a variety of food manufacturing processes (dehydration and pickling).

Fresh garlic is widely used in cooking. In India and other Asian and Middle East countries, it is used in pickles, curry powder, curried vegetables, meat preparation, tomato ketchup. In the Philippines, Central Eastern Asia and in parts of the tropics, the green tops as well as bulbs of garlic are used. Dehydrated garlic in powdered or granulated form has replaced the use of fresh bulbs for industrial and home use in many countries. Dehydrated products of garlic are common as a condiment and in the food industry. It is reported that in America about 50% of the total production of garlic is dehydrated and sent to food processors.

Garlic is a frost-hardy bulbous perennial erect herb of 30100 cm in height with narrow flat leaves and bears small white flowers and bulbils (Janick, 1979). It is a herbaceous annual for bulb and a biennial for seed production. The shape of garlic is smooth, round and solid for its entire length unlike onion which is hollow. Many cloves of garlic do not produce flowerstalks. The inflorescence may be partially or not at all

Table 1 Area, production, productivity and per capita availability of garlic in different countries during 1999

Country Area Production Productivity Per capita

(000 ha) (000 mt) (kg/ha) availability


Africa 17 178 10311

Algeria 8 30 3750 1.00

Egypt 5 114 25366 1.73

Morocco 2 7 3829 0.26

N.C. America 25 301 12218

Mexico 9 65 7647 0.68

USA 14 224 16250 0.82

South America

Argentina 15 181 11727 5.01

Brazil 11 63 5563 0.38

Peru 5 30 5883 1.21

Asia 682 7280 10667

China 424 5690 13421 4.53

India 113 452 3996 0.46

Indonesia 11 38 3599 0.18

Korea Rep. 41 484 11916 10.50

Turkey 14 106 7571 1.64

Myanmar 14 53 3782 1.19

Bangladesh 13 40 3022 0.32

Thailand 21 131 6235 2.17

Europe 125 699 5594

Italy 4 34 8550 0.59

France 6 45 7759 0.77

Yugoslavia 12 44 3631 4.14

Russian Fed. 25 161 6381 1.09

Romania 12 58 4833 2.58

Spain 25 170 6827 4.29

Ukraine 21 79 3762 1.55

Oceania 1 7143

New Zealand 1 7143 0.26

World 889 8776 9875 1.49

Source: FAO Quarterly Bulletin of Statistics (3/4) 1999.

exerted, its bulbils forming a swelling somewhere within the false stem a few cm above the bulbs. The bulb consists of 635 smaller bulblets called cloves and is surrounded by a thin white or pinkish papery sheath (Bose and Som, 1986).

Alliums have been cultivated for thousands of years for therapeutic and prophylactic properties, religious significance, and flavour and taste. The Chinese,

Table 2 Trend of area, production and productivity of garlic in the world


1986 1999 Increase (%)

Area (million ha) 0.41 0.89 115.78

Production (million ton) 2.54 8.78 245.92

Productivity (ton/ha) 6.16 9.88 60.41

Sources: FAO Quarterly Bulletin of Statistics (3/4) 1999 and FAO Production Year Book 1988.

Sumerians, Indians and Ancient Egyptians are all known to have consumed garlic over

4000 years ago. Among others, Hippocrates (430 BC) and Theophras Tuso (322 BC)

have described the consumption of garlic in the Greek and Roman period

(Rabinowitch and Brewster, 1990). Garlic is thought to have originally come from Central Asia and Southern Europe, especially the Mediterranean region (Thompson and Kelly, 1957). Some authorities consider that Allium longicuspis Regel, which is endemic to Central Asia, is the wild ancestor and spread in ancient times to the Mediterranean region.

Garlic presents an interesting problem of classification and quality given the wide range of cultivars, differing in maturity, bulb size, clove size and number, scale colour, bolting, number and size of inflorescence bulbils and presence or absence of flowers

(Bose and Som, 1986). Taxonomists have recognised at least four botanical varieties within Allium sativum L., namely A. sativum L., Var sativum, A.sativum L. Var., Ophioscorodon (Link) Doll, A. sativum L. Var Pekinense (Prokh) Maekawa and A. sativum L. Var nipponicum Kitamura. Jones and Mann (1963) could not satisfactorily classify many garlic cultivars into clearly defined botanical varieties, because many show combinations of characteristics from two or more varietal groups. It appears, then, that the above botanical classification has little advantage. Following criteria may be of practical use for distinguishing different garlic cultivars (Rabinowitch and Brewster,


Morphological characteristics such as: Bolting type, number and size of cloves, number of leaf axils, forming cloves, number of secondary cloves formed in a lateral bud, bulb weight, colour of the outer protective leaf of the cloves, number of protective leaves, width and length of foliage, plant height and tenderness of the green leaves.

Physiological and ecological characteristics: Time of bulbing and maturity, low temperature and long day requirements for bulb formation, winter hardiness and bulb dormancy.

2 Chemical structure

Garlic or any other Allium is characterised by the remarkable sulphur-containing compound present in it which gives distinctive smell and pungency. Uninjured bulb of garlic contains a colourless, odourless water soluble amino acid Alliin which includes the presence of the volatile flavour compounds. These precursors are of the general name S-alk(en)yl cysteine sulphoxide. The general structure of the flavour precursor is:




The group to the right of R moiety is the L-cysteine sulphoxide group. The group R can be:

1. CH3 -called (+)-S-methyl

2. CH3CH2CH2 -called (+)-S-propyl

3. CH3CH=CH -called trans (+)-S-(1-propenyl)

4. CH2=CHCH -called (+)-S-(2-propenyl)

When the fresh tissue is damaged, the flavour precursors react under the control of the enzyme alliinase (S-alk(en)yl-L-cysteine sulphoxide Lyase) to release the highly reactive sulphenic acids plus ammonia and pyruvate. Alliin, or S-allyl cysteine sulphoxide, was the first sulphur compound isolated from Allium sativum (garlic). The enzyme alliinase is confined to the cell vacuole, whereas the flavour precursors are confined to the cycloplasm probably within small vesicles associated with their presence in the cell. Hence the enzyme has access to the precursors only when cells are disrupted. In garlic, alliinase catalyses the formation of allicin, which gives fresh garlic its characteristic smell

(Brewster, 1994).

Alliinase (E.C., S-alk(en)yl-L-cysteine sulphoxide cyase is the enzyme ultimately responsible for the development of the flavour compounds. The reaction catalysed by the enzyme is a beta elimination of the S-alk(en)yl sulphoxide group from the substrate:




| || NH2 NH

Both products of the reaction are chemically unstable; the Ketimore product spontaneously hydrolyses to pyruvate and ammonia while the reactive sulphur species will combine with any of a number of co-reactants, most often another of the same species, to give a range of flavour components. Thus the reaction is commonly described as:


|| || ||


| NH2

Rabinowitch and Brewster (1990) have elaborated the details about the alliinase solubility and stability, purification, physical, chemical and catalytic properties. They report that alliinase from Alliums is less soluble. It is difficult to maintain this enzyme in aqueous solution. A cosolvent is required to maintain the enzyme activity. It is further reported that alliinase enzyme has a tendency to aggregate and precipitate and gets totally inactivated by freezing.

Alliinase from garlic was first prepared by Stoll and Seebeck in 1947; however, the preparation was relatively crude. A common feature of the preparation is the use of a polyalcohol cosolvent, 10% glycerol in the case of garlic enzyme. The purification of garlic enzyme also required the presence of 10 M pyridoxal phosphate in the buffers. The garlic enzyme has been described as having a molecular weight of 130,000 with two subunits of 65,000. Spectral studies on alliinase from garlic revealed an absorption peak at 420 nm characteristic of pyridoxal phosphate. Garlic alliinase has been reported to contain no carbohydrate. However, the presence of a subunit band giving a periodic acid schiff base stain on SDS gels of the purified enzyme indicates that the enzyme is a glycoprotein.

The general catalytic properties of alliinase were well described long before the enzyme was purified to homogeneity. A broad pH optimum of 58 was described by Stoll and Seebeck (1947) for the garlic enzyme with a temperature optimum under the

condition of assay of 37C. They also made observations on the specification of the reaction: the substrate must be a derivative of (-)L-cysteine, the sulphur atom must be linked to an aliphatic group, the amino group of cysteine must not be substituted and the sulphur atom must be in the sulphoxide form with the + and configurations both being substrate.

3 Processing Raw garlic no doubt has the ideal flavour and provides desirable textural and water retaining properties when incorporated into food products, bulk of raw garlic is water and lacks flavour and aroma. Also handling and storage costs are more when garlic is used in raw form. Dehydration or flavour extraction reduces the quantity which ultimately lowers the transportation and storage costs. Processing, however, may introduce undesirable changes in appearance. It may also modify the natural balanced aroma and flavour.

Many modern automated food processing plants are not able to handle the raw form of garlic as such a range of garlic products are available to meet the particular needs of the market. Garlic flakes, garlic powder, garlic oil and garlic juice are some of the processed forms of garlic which are widely used by the food industry. Garlic capsules and tablets are also prepared and these products have a ready market in view of their high medicinal values.

3.1 Garlic dehydration A schematic representation of the process for garlic dehydration is shown in Fig. 1. The garlic bulb is broken into individual cloves by passing between rubber covered rolls which exert throughpressure to crack the bulb without crushing the cloves. The loose paper shell is removed by screening and aspirating. The cloves are then washed in a flood washer. At this stage the root stubs are floated off. Slicing is then done on a specially designed high-speed cutter. The sliced garlic cloves are then spread on drying trays which in turn are stacked on transfer cans. Tunnel type dehydrators are used for dehydration. The cans are placed in these tunnels and hot air is blown across the trays. The sliced garlic cloves are dried down to about 10% moisture in this operation which takes about

1015 hours at 6065sC. It is, however, preferable to keep the temperature below 57sC

while drying (Pandey, 1997).

Part of the remaining moisture is usually removed in a finishing operation for which garlic cloves are placed in large bins. Warm air is forced upward through the bins. This bin drying and conditioning operation may take about 30 hours. In these drying operations temperature must be controlled so that browning or scorching do not occur. After the slices are dried, they may be screened for removal of large partially dried slabs and fines. The fines may account for one third of the total dehydrated product. Usually fines are ground into powder. The slabs may be broken up and redried. The slices are prepared in the form of flakes. Grinding and packaging of powder is done in low humidity surroundings to avoid gumming and caking. Garlic is commercially dried to

6.5% moisture.

It is reported that dehydrated garlic is available in six forms: powdered, minced, coarse, granulated, chopped and diced. It is generally considered that about 5 kg fresh garlic bulbs from the field make 1 kg of dried product. On the basis of chemical, microbial and sensory studies, it is also reported that 60sC is the maximum temperature

Fig. 1 A schematic representation of the process for garlic dehydration. (From Van Arsdel et al., 1973).

for dehydration of garlic. Hot air drying technique is considered to be the most economical. Storage of garlic powder was best achieved in cans, the use of sealed polyethylene bags being considered unsatisfactory. Odourless garlic powders as health supplements may be produced by inactivating alliinase by contacting garlic with fumaric acid/fumarate or by physically separating garlic powder and alliinase. Freeze drying of the garlic/cyclodextrin (70:30) mixture has also been claimed to produce an odourless product. Dehydrated garlic is prone to discoloration. Darkening is associated with non-

enzymic Maillard reactions and may be prevented by reducing temperature. A green discoloration associated with the maceration of garlic tissue may be minimised if dormant tissue is processed (Rabinowitch and Brewster, 1990).

There are reports that there is adverse effect of processing on quality and intensity of flavour. Dehydration has been associated with loss of more than 90% of the flavour intensity (Pruthi, 1980). This represents both a potential environmental problem and a significant economic loss. The origins of such losses has been examined and it has been concluded that they occur prior to the realisation of a critical moisture content, wherefrom the flavour may be envisaged as being sealed within the product (Mazza and Le Maguer, 1979).

3.2 Garlic oils Volatile oils comprise 0.1 to 0.25% of the fresh weight of garlic. Garlic oil is recovered by steam distillation of freshly ground cloves. It is a reddish brown overpowering liquid. One gram of oil is equivalent in flavouring terms to 900 g fresh garlic or 200 g dehydrated garlic powder. The high pungency of garlic oil makes it difficult to use directly. The oil is commonly diluted in vegetable oil. It is being used in ice-cream, ices, confectionery, baked goods, chewing gum and condiments. The rates of 6 ppm in baked products, 0.010.3 ppm in beverages, 16 ppm in condiments, 12 ppm in chewing gums,

12.9 ppm in confectionery and 40 ppm in ice-cream are being used.

3.3 Other products Garlic is also processed in the form of garlic juice and garlic salt. Garlic oleoresin is a dark viscous liquid, having 12 times the flavour of dehydrated garlic or 50 times that of fresh garlic cloves. Garlic paste is formulated from suitable flavours and viscous edible base.

Garlic salt is comprised of a free flowing, uniformly blended dry mixture of non- iodised salt, the approximate composition of which is shown in Table 3. Garlic salt should not contain more than 2.5% moisture, more than 81% salt and should have moisture-free white garlic powder between 1819%, and 12% calcium stearate. Garlic

Table 3 Approximate composition (100 g) of garlic salt

Garlic salt Water 1.4 g Energy 63 kcal Protein 3.2 g

Fat 0.1 g Carbohydrate 13.8 g Fibre 0.4 g Ash 81.5 g Ca 220 mg Fe 1 mg Mg 11 mg

P 79 mg

K 212 mg Na 31.4 g Zn 1 mg Vitamins

salt has much wider culinary potential than powder and one tablespoon is equivalent to a clove of fresh garlic.

4 Uses Garlic is used practically all over the world for flavouring various dishes. In America about 50% of the entire output of fresh garlic is dehydrated and sold to food processors for use in mayonnaise products, salad dressings, tomato products and in several meat preparations. Raw garlic is used in preparation of garlic powder, garlic salt, garlic vinegar, garlic cheese croutons, potato chips, garlic bread, garlicked meat tit-bits and garlicked bacon, etc., which have been boosted in the American market. Spray-dried garlic products including garlic preparations are also available in the market. In Italy, Europe and Latin America, the spectacular popularity of garlic is shown by the methods by which it is boosted by the garlic growers. In India and other Asian and Middle East countries, garlic is already being used in several food preparations notably in pickles, curry powders, curried vegetables, meat preparations and tomato ketchup, etc. There has been increasing demand for garlic by the food industries for garlic powder as a condiment. Oil of garlic has now been appreciated as a valuable flavouring agent, for use in all kinds of meat preparations, soups, canned foods and sauces (Pruthi, 1987).

5 Functional properties and toxicity Garlic has been considered as a rich source of carbohydrate, proteins and phosphorus. Ascorbic acid content was reported to be very high in green garlic (Prodan et al., 1977). The nutritive composition of fresh and peeled garlic cloves and dehydrated garlic powder as reported by Pruthi (1987) is given in Table 4.

Studies suggest that garlic, which contains more than 200 different compounds, has biological activities that can have medically important effects. Garlic has been used as an excellent carminative, a nerve tonic and an antiseptic agent in Hindu medicine for centuries (Aman, 1969). However, it has been only recently that its medical benefits have been explored in detail. The functional properties of garlic have been reviewed by Agarwal (1996), Koch and Lawson (1996) and Lawson (1998a). These properties include the following:

cholesterol lowering properties reported by numerous studies (including Reuter and Sendl, 1994; Han et al., 1995; Adler and Holub, 1997). These studies have reported an average 10% reduction in total serum cholesterol. Evidence suggests that these effects are due to allicin or allicin-derived compounds (Yeh and Yeh, 1994; Gebhardt and Beck, 1996). Some recent studies, however, have produced contradictory results

(Berthold and Sudhop, 1998), though this may be due to the composition of the garlic supplements studied (Lawson, 1998b)

garlic significantly lowers blood pressure (Silagy and Neil, 1994; Das et al., 1995a and


garlic has an influence on platelet aggregation, an important factor in cardiovascular disease (Lawson et al., 1992; Han et al., 1995; Batirel et al., 1996). It also has an effect on blood coagulation and fibrinolytic activity which are factors in the development of thrombosis (Han et al., 1995; Breithaupt-Grogler et al., 1997)

Table 4 Nutritive composition of fresh/peeled garlic cloves and garlic powder (Pruthi, 1987)

Nutrients Fresh peeled Garlic powder garlic cloves

1. Moisture (%) 62.8 5.2

2. Protein (%) 6.3 17.5

3. Fat (%) 0.1 0.6

4. Mineral matter (%) 1.0 3.2

5. Fibre (%) 0.8 1.9

6. Carbohydrates (%) 29.0 71.4

7. Calcium (%) 0.03 0.1

8. Phosphorus (%) 0.31 0.42

9. Iron (%) 0.001 0.004

10. Sodium (%) 0.01

11. Potassium (%) 1.1

12. Niacin (%) 0.7

13. Vitamin-A 0 17510/100 g

14. Vitamin-B (mg/100 g) 0 0.68

15. Vitamin-B2 (mg/100 g) 0 0.08

Vitamin-C (mg/100) 13.00 12.00

17. Nicotinic acid (mg/100 g) 0.4

18. Caloric value (food energy) 142 calories/100 g 380 calories/100 g

epidemiological studies have suggested a link between garlic consumption and a reduced risk of stomach cancer (Steinmetz et al., 1994; Han et al., 1995; Milner,

1996). Various constituents of garlic have been identified as inhibiting tumour growth, notably garlic-derived organosulphides (Srivastava et al., 1997; Pinto et al., 1997; Riggs et al., 1997; Hu and Singh, 1997; Sakamoto et al., 1997).

Garlic also has antioxidant properties which are helpful in preventing cancer and cardiovascular disease (Horie et al., 1992; Phelps and Harris, 1993; Imai et al., 1994).

garlic has antibiotic properties and has been used to treat wounds when other antibiotics were not available (Fenwick and Hanley, 1985a; Han et al., 1995). Although anticarcinogenic activity of garlic has been well documented (Lau et al.,

1990), the mechanism by which garlic compounds prevent carcinogenisis of many chemicals is not entirely clear. One possible mechanism is the ability of sulphur- containing garlic compounds to block the activation of procarcinogens to carcinogens by hepatic mixed function oxidases. It is interesting to note that diallyl sulphide has been found to inhibit hepatic mixed function oxidases at high doses (Dalvi and Salunkhe,

1993). Garlic is also effective against gastric cancer.

5.1 Toxicity of garlic

Since the consumption and level of sulphur-containing ingredients of garlic that are supposed to be toxic are so low, acute or fatal garlic poisoning in humans is very rare. A case report on wild garlic poisoning in sheep indicates that the poisoned animals showed hemolytic anemia, jaundice, very dark discoloration of the kidneys and hemoglobinuria

(Stevens, 1984). Histopathological examination of the dead animals showed a marked tubular necrosis and hemoglobin casts in the kidneys and centrilobular necrosis of the liver. These toxic effects were attributed to a high level of S-methylcystein sulphoxide, a sulphur-containing amino acid which is a precursor of hemolytic anemia factor dimethyl

disulphide found in garlic. Compounds such as di(prop-2-enyl) disulphide present in garlic have been found to cause contact dermatitis (Mitchell, 1980; Hjorth and Roed- Peterson, 1976) and may also be responsible for occupational allergy.

The mechanism of toxic action of sulphur-containing compounds of garlic, especially allicin, has been reported to lie in their ability to react with SH groups of enzymes and properties. Therefore, though garlic has many medicinal properties, it has serious toxic effects, if taken in large quantities for medicinal uses, which may present as anemia, stomach ulcers, severe allergic reaction and suppression of testicular functions. Further studies on safety of garlic are thus needed.

6 Quality issues

The quality of the raw material used in the processing industry determines to a large extent the quality of the finished product. Raw materials of poor quality cannot be expected to result in a final product of high quality even with the best processing methods. Therefore, gaining an understanding of the nature of the raw material and of its possible defects is an essential step in building quality into a product. Likewise thorough knowledge of the likely effects of defects, defective raw materials on both processing efficiency and quality of finished product is important. The bulb of garlic should have been harvested at proper maturity stage and tacked in windrows to cure. After about a week or when they have dried thoroughly, the bulbs are topped by cutting off leaves and roots with shears. Diseased and damaged bulbs are sorted out in the field. The bulbs of a variety should be thoroughly sorted and graded. The cloves of garlic variety should be sound and practically free from mould, disease, soil outer skins, stems, leaves and roots as per International Standard ISO-5560: 1997.

General: Dehydrated garlic shall conform to the requirement of this International

Standard and on rehydration shall regain characteristics similar to those of fresh garlic.

Colour: The colour of dehydrated garlic shall be the characteristic of the cultivar used, i.e. between white and pale cream. The product shall be practically free from scorched, toasted and baked particles.

Odour: Dehydrated garlic after rehydration by the method specified under the International Standard shall have a characteristic, pungent odour, free from foreign odour and off odour such as those coming from mouldy, rancid, fermented or burnt particles.

Flavour: The flavour of the dehydrated garlic is assessed after rehydration in accordance with the method specified under the International Standard. It shall be the characteristic of parboiled garlic and free from foreign flavour and off flavour such as those coming from mouldy, rancid, fermented or burnt particles.

Freedom from insects, moulds, etc.: Dehydrated garlic shall be free from live insects and practically free from moulds, dead insects, insect fragments and rodent contamination visible to the naked eye or with such magnification as may be necessary in any particular case. In case of dispute, the contamination of garlic in powder form shall be determined by using the method specified in ISO-1208.

Extraneous matter: The total percentage of extraneous matter, i.e. vegetable matter originating exclusively from plants, such as particles from skins and roots shall not exceed 0.5% (m/m).

Table 5 Chemical requirements of dehydrated garlic

Characteristic Requirement Test method

Moisture content, % (m/m), max. 8 ISO 939

Total ash, % (m/m), on dry basis, max. 5.5 ISO 928

Acid-insoluble ash, % (m/m) on dry basis, max. 0.5 ISO 930

Volatile organic sulphur compounds content, 0.3 ISO 5567

% (m/m) on dry basis, min.

Cold-water-soluble extract, % (m/m) on dry basis,

min., 70 ISO 941

max. 90

Dehydrated garlic may be divided into the broad categories given below:

Dehydrated garlic slices It is a product obtained by cutting garlic cloves into slices and removing broken pieces smaller than 4 mm by sieving.

Dehydrated garlic flakes or pieces These are the products passing through a sieve of aperture size from 1.25 mm to 4 mm according to the case. The particles do not have any definite shape.

Dehydrated garlic grits

It is a product passing through a sieve of aperture size 250 m to 1.25 mm.

Powdered garlic

It is a homogenous product 95% of which passes through a sieve of aperture size

250 m. Dehydrated garlic shall comply with the requirements for chemical and physical

properties specified in Table 5 when tested by the specified method. M/s. Garlico Industries, Mandsaur, Madhya Pradesh, India has also given the specifications of garlic powder as required in the United States (Table 6).

Requirements for sampling are as follows:

Dehydrated garlic powder or grits: Sampling of the product is done in accordance

Table 6 Specifications of garlic powder

Parameter Standard

Description Off-white/Yellow colour powder

Allicin yield Not less than 12,500 ppm Alliin Not less than 28,000 ppm Gamma Gluamylcysteins Not less than 6,000 ppm Total Thiosulphinates Not less than 13,000 ppm Total Sulphur Not less than 6,000 ppm Moisture 6% maximum

Granulation +35 Mesh-max. 1%

+45 Mesh-max. 1%

+80 Mesh-max. 15% Total Plate Count 100,000 Cfu/g maximum Mould Content 1000 Cfu/g maximum E.Coli None Detected Salmonella None Detected

with ISO 948 using a conical sample or other suitable implement to remove aseptically or representative sample.

Dehydrated garlic slices, flakes or pieces: Certain problems arise as a result of the friability of the product and the danger of settling within the container. It may, therefore, be necessary to take the entire contents of a single container because, during transport, the garlic may settle with the larger pieces towards the top and smaller pieces towards the bottom.

Test methods: The samples of dehydrated garlic shall be tested for conformity with the requirement of this International Standard by following the methods of physical, organoleptic and chemical analysis specified above and in Table 5.

As far as packing and marking are concerned, dehydrated garlic shall be placed in clean, sound and dry containers made of a material which does not affect the product but which protects it from light and from ingress of moisture. The packaging shall also comply with any national legislation relating to environmental protection. The following particulars shall be marked directly on each package or shall be marked on a label attached to the package:

name of the product, botanical name and trade names, if any;

name and address of the producer or packer or trademark, if any;

code or batch number;

net mass;

producing country;

any other information requested by the purchaser, such as year of production and date of packing, if known;

reference to this International Standard; and

whether the product contains additives, and if so, which ones, in the case of countries where they are permitted.

Methods of rehydration and sensory evaluation of dehydrated garlic are:

Garlic slices: Vessel, of about 500 ml capacity made of a material which will not impart a foreign taste or affect the colour of the preparation, dish made of porcelain or white earthenware and stainless steel spoon are the apparatus used in rehydration. Natural, potable water as neutral as possible is used. Sample of 10 g 0.1 g is weighed and transferred to the vessel containing 500 ml of cold water. It is then boiled at 99sC, keeping the vessel covered for 10 minutes 1 min. Volume is made up to 500 ml with cold water and then poured into the dish. Immediately then sensory evaluation of appearance of the cooking water (colour and clarity), colour of the preparation, odour, tenderness and flavour is carried out.

Garlic powder, grits, flakes or pieces: Vessel of about 1000 ml capacity made of a material which will not impart a foreign taste or affect the colour of the preparation, dish made of porcelain or white earthenware, and stainless steel spoon are the apparatus used in rehydration. Flour made from durum wheat from the most recent harvest and known to be of good quality is used along with natural, potable water as neutral as possible are used as reagents. 1000 ml of cold water is transferred to the vessel and 30 g of the flour is added while stirring continuously. The mixture is then heated and stirred continuously until it reaches boiling point and then simmered for 2 minutes. Weighing is done to the nearest 0.001 g, 0.4 g of the garlic then placed in the dish. 250 ml of the medium prepared is added and allowed to stand for 5 minutes. Stirring is done from time to time. Sensory evaluation is then done for odour and flavour.

Table 7 Microbiological characteristics of dehydrated garlic

Characteristic Recommended specification Test method

M M Microorganisms at 30sC, per gram, max. 105 106 ISO 4833

Presumptive Escherichia coli, per gram, max. 10 102 ISO 7251

Yeasts and moulds at 25sC, per gram, max. 103 104 ISO 7954

Clostridium perfringens, per gram, max. 10 102 ISO 7937

Staphylococcus aureus, in 1 g Absent ISO 6888

Salmonella, in 25 g Absent ISO 6579

Tests conducted in laboratories representing the producers and the users of this product have shown that the microbiological characteristics as given in Table 7 can be considered as acceptable. These are for information only.

Packages of dehydrated garlic should be stored in covered premises, well protected from the sun, rain and excessive heat. The storeroom should be dry, free from unpleasant odours and protected against the entry of insects and other vermin. While transporting, the containers should be clearly marked with warning against careless handling which might lead to perforation of the containers. They should be dry and cool and stored well away from ships boilers and bilges.

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