PUTIH vs KUNING???

Sebenarnya warna asal tepung gandum ialah berwarna kuning. Bukan warna putih melepak seperti yang kita lihat dalam bungkusan tepung gandum yang jual kat kedai tu. Kebanyakan atau hampir kesemua kilang di Malaysia telah menggunakan sejenis peluntur atau bahan kimia yang sangat berbahaya untuk melunturkan warna kuning tepung tersebut dan supaya tepung tersebut nampak lebih putih, cantik dan menyelerakan.

Apakah bahan kimia yang terdapat di dalam tepung gandum? BENZOYL PEROXIDE! Apakah kegunaan sebenar bahan kimia ini? Ianya merupakan salah satu bahan peluntur yang sangat kuat. Ia berkemampuan melunturkan warna baju, warna hitam rambut dan tidak hairan la warna kekuningan tepung gandum yang masih belum diproses dapat dilunturkan. DAN, bayangkan pula jika bahan kimia ini masuk ke dalam perut anda? Tak dapat dibayangkan kesannya. Sesetengah jenama tepung gandum menyatakan bahawa tepung gandum mereka mengandungi bahan ini dengan kuantiti yang dibenarkan.. namun sanggupkah anda menanggung risikonya?? Tepuk dada tanya selera, mungkin selepas ini kita perlu berhati2 dalam memilih bahan makanan...

Apakah Benzoyl Peroxide, menurut beberapa laman web bahan ini adalah sejenis bahan toksik yang:

· Bahan penggalak tumor
· Boleh menyebabkan alahan pada kulit
· Bahan mutagen iaitu bahan yang boleh menyebabkan mutasi pada sel badan.
· Bahan peluntur kuat yang mampu melunturkan iaitu menukarkan ke warna putih pakaian dan juga rambut yang berwarna.

Proses pemutihan tepung gandum dilakukan adalah dengan cara mencampurkan tepung gandum dengan bahan kimia BP ini. Dalam tempuh yang singkat, iaitu tidak sampai pun 1 jam, semua tepung gandum ini akan bertukar ke putih. Selain menukar (meluntur) kepada warna putih, BP juga bertindak balas dengan tepung gandum ini lalu menukarkan protin gluten yang terdapat dalam tepung gandum ini. Ia juga mengakibatkan sebahagian nutrisi didalam tepung gandum yang asal merosot. Ini mengakibatkan serangga kurang menggemari tepung putih berbanding tepung gandum yang asal (sila baca artikel berbahasa Inggeris di bawah). BP ini akan terus berada di dalam tepung putih ini apabila dipasarkan.

Kenapa ia (BP) merbahaya?

Petikan dari sebuah laman WEB -  Benzoyl Peroxide is a highly potent chemical often used in low concentrations as an acne treatment.  Benzoyl Peroxide basically works as a peeling agent, stripping dead skin cells and killing bacteria within pores.  Pure benzoyl peroxide is highly flammable, explosive, toxic, and is suspected of being a possible tumor promoter.  Although Benzoyl Peroxide is generally considered safe at low concentrations, since it breaks down in contact with skin, it is known for causing nasty side effects such as hives, swelling of the face, itching, and dry and peeling skin.  It is also a powerful bleaching agent and will cause discoloration when it comes in contact with clothing and hair.

Dari laman WEB yang lain pula – Classified as: TOXIC, FLAMMABLE and EXPLOSIVE Toxicology Possible tumor promoter. May act as a mutagen. Toxic by inhalation. May be harmful if swallowed and in contact with skin. Eye, skin and respiratory irritant.  Typical TLV 5 mg/m3.

Satu lagi laman WEB - Benzoyl peroxide presents a number of hazards. Firstly, it is potentially explosive when mixed with organic material.  Friction or grinding may also be sufficient to make it explode. The compound is very flammable. Benzoyl peroxide is toxic if you breathe it in, and may be harmful if you swallow it or get it on the skin. In addition, benzoyl peroxide may act as a tumor promoter.
 

Itulah sebabnya BP digunakan untuk menukarkan warna tepung gandum kepada warna putih kerana BP adalah satu bahan peluntur yang amat kuat hinggakan rambut hitam boleh bertukar putih bila disentuhkan BP ini.  Proses pemutihan tepung dilakukan dengan mencampurkan tepung gandum dengan bahan kimia ini. Dalam tempoh yang singkat, iaitu tidak sampai 1 jam, semua tepung gandum ini akan bertukar menjadi putih. Selain menukar (meluntur) kepada warna putih, BP juga bertindak balas dengan tepung gandum dengan menukarkan protin gluten yang terdapat dalam tepung. Ia juga mengakibatkan sebahagian nutrisi di dalam tepung merosot. Itulah sebabnyaserangga kurang menggemari tepung putih berbanding tepung gandum yang asal.

Persoalannya…kenapa Benzoyl Peroxide terus berada di dalam tepung putih yang dipasarkan sedangkan pihak berwajib arif tentang kandungan bahan toksik yang boleh mendatangkan kesan sampingan?

Isi emel seterusnya…”Saya sebagai seorang yang pernah mengalami “acute gout” sudah masak benar dengan kesan negatif tepung putih ini ke atas pesakit gout. Kepada penghidap penyakit gout, sila buat eksperimen ini.

Sebagai permulaan, kawallah pemakanan sehingga gout anda berkurangan dan hampir tidak ada. Setelah itu, makanlah makanan yang dibuat dari tepung putih seperti mee kuning atau roti canai dalam kuantiti yang banyak dan tunggulah kesannya.

Insya-Allah dalam tempuh 24 jam, pesakit gout akan mengalami simptom gout yang serius.  Itulah kesan dan akibat dari memakan tepung putih yang mengandungi bahan kimia Benzoyl Peroxide.

Sebagai eksperimen kawalan (control experiment), lakukan pula eksperimen yang sama seperti di atas tetapi menggunakan spageti atau makaroni atau capati. Kesemua makanan ini berasal dari gandum juga namun tepung ini tidak dicampurkan dengan Benzoyl Peroxide.  Insya-Allah eksperimen ini tidak akan menyebabkan symptom gout.

Kedua-dua eksperimen ini menunjukkan dengan jelas bahawa bukan gandum yang membahayakan pesakit gout tapi kandungan Benzoyl Peroxide di dalam tepung. Mee kuning pula, selain BP, kandungan Asid Borik sebagai pengawet menambah lagi derita penghidap gout. Kepada penghidap penyakit gout, diabetes dan arthritis, elakkan makanan yang mengandungi tepung gandum putih (yang telah dilunturkan oleh BP) seperti mee kuning, roti canai, roti putih serta kuih muih yang diperbuat dari bahan ini.  

Percayalah, kesan negatif dari BP tidak ketara dalam tempoh singkat.  Namun setelah mengambil produk berasaskan tepung putih untuk tempoh yang panjang, lambat laun kesannya akan terasa jua.  

Tidakkah mencegah lebih baik dari merawat?”

IKHSAN: UTUHPALOI.COM

ALL ABOUT BENZOYL PEROXIDE

1 Summary

Benzoyl peroxide (BP) has been used for over 50 years as a bleaching agent in flour, whey processing and  milk for Italian cheese making. It was used for bleaching flour and cheese at concentrations of up to 40 mg/kg, while bleaching of Cheddar cheese whey has been done successfully using 20 mg/kg BP and holding for an hour at 60-63 °C. As benzoyl peroxide is almost totally converted (> 91%) to benzoic acid during cheese making and any remaining traces would further be reduced by processing of whey.

 Therefore the  intake assessment should be made on the additional benzoic acid incorporated in the diet from the use of  benzoyl peroxide to bleach whey.    JECFA has evaluated the use of BP as a bleaching agent in flour and concluded that treatment at  concentrations up to 40 mg/kg was acceptable (WHO, 1964). Moreover, at the 59th meeting JECFA  concluded that benzoyl peroxide was of "no safety concern" when used as a flavouring agent (based on  current levels of intake) (WHO, 2002).

Concentration of benzoyl peroxide commercially used is much lower than 100 mg/kg. Only 15% of the  world's cheese production is coloured and hence is subject to use BP.  Besides, not all of the coloured whey  undergoes bleaching process before drying.

2 Description

Benzoyl peroxide is colourless, crystalline solid having a faint odour of benzaldehyde. It is insoluble in  water, slightly soluble in alcohol, and soluble in chloroform and ether. One g dissolves in 40 ml of carbon  disulfide. It melts between 103 °C and 106 °C with decomposition.  Benzoyl peroxide, especially in the dry  form, is a dangerous, highly reactive, oxidizing material and has been known to explode spontaneously.

3 Manufacturing.

Benzoyl peroxide is synthesized commercially by the reaction of benzoyl chloride, sodium hydroxide, and hydrogen peroxide. Traces of benzoic acid remain after usual purification procedures. 

4 Chemical Characteristics

4.1 Nomenclature and physical properties.

The chemical names are benzoyl peroxide or dibenzoyl peroxide. Its Chemical Abstract Service (CAS)  number is 94-36-0 and International Numbering System (INS) is 928, its chemical formula is C14H10O4, and its molecular weight is 242.23. The chemical structure is shown in figure 1.The physical properties of benzoyl peroxide reported in (FNP5) indicates that it is insoluble in water, slightly soluble in ethanol, soluble in ether and chloroform.  It has a melting range of 103 - 106°C with decomposition.

 4.2 Analytical Methods

Method of assay  Dissolve about 250 mg of the sample, accurately weighed, in 15 ml of acetone in a 100-ml glass-stoppered bottle. Add 3 ml of 50% (w/v) potassium iodide solution and swirl for 1 min. Titrate immediately with 0.1 N sodium thiosulfate (without addition of starch as an indicator). Each ml of 0.1 N sodium thiosulfate is equivalent to 12.11 mg of C14H10O4. 

Methods of determination of benzoyl peroxide (as benzoic acid) in foods

Determination of benzoyl peroxide in flour

The method 13.049 described in AOAC is used to determine benzoyl peroxide in flour (AOAC, 1998).  Determination of benzoyl peroxide in this method depends on its ether extraction.  Another method have been developed by Feigl et al. (1961) to detection of benzoyl peroxide through the pyro-oxidation of hexamine (limit of detection is 10 µg benzoyl peroxide). In this method, a drop of the sample or its solution in benzene is placed in a micro test tube.  Three drops of 5% solution of hexamine in benzene are added and the mouth of the test tube covered with a disc of filter paper moistened with Nessler's reagent. The tube is then immersed to 3/4 of its length in a 100°C glycerol bath that may be heated to 130°C without danger of explosion.  The development of a grey or black stain on the reagent paper indicates a positive response. 

Also, Saiz (2001) developed a method to analyze benzoyl peroxide in flour using HPLC. Fifty grams of flour previously treated with the benzoyl peroxide bleaching  agent is mixed with 100 ml  of diethyl ether.  After settling, an aliquot of the clear ether was removed and a portion of this injected into the HPLC.  The separation took place on a 250 x 4.6 mm Alltech Econosphere CIS (l0 µm) column in a mobile phase of methanol/water (80:20). Analysis was carried out by a UV-vis detector.

Determination of benzoyl peroxide in cheese 

A method developed by Karasz et al. (1974) to determine benzoyl peroxide added to cheese.  The principal of this method is to estimate benzoic acid, as a reduction end product,  by gas chromatographic.  Fifty grams of comminuted cheese is blended with 75 ml 1% H3PO4 , 50 ml ethanol, and 100 ml ethyl ether.  The resulting precipitate and remaining solids are extracted twice with two washings of 100 ml ethyl ether and 100 ml petroleum ether.  One gram cuprous chloride, Ig electrolytic copper powder and 2.5 ml HC1 are added to reduce the residual bleach.  Solvent partitioning and treatment with KMNO4 are used for purification.  The benzoic acid is then transferred to chloroform using lauric acid as an internal standard and determined by flame ionization gas chromatography, with a column containing 5% FFAP + 0.5% H3PO4 on Chromosorb W.

Determination of un-reacted benzoyl peroxide in whey .

The following method has been used by Chang et. al. (1977) to determine un-reacted benzoyl peroxide in whey.  A 500 ml aliquot of whey is treated with 6 mg peroxide.  This mixture is subsequently extracted three times with ether which had been freshly distilled over sodium.  The ether extracts is dried with sodium sulfate and evaporated.  The resulting residue was tested for peroxide by the method of Hamm et al.(1965).

5 Functional uses

It is used as a bleaching agent for certain foods, an oxidizing agent, a polymerizing initiator in the manufacture of plastics, a curing agent for silicone rubber, a constituent of ointments for skin disorders, and an ingredient in various industrial processes.

Benzoyl peroxide has a long history of use in the food industry as a bleaching agent added for flour, whey, and milk for cheese making.  A premix of 32% benzoyl peroxide  and 68% cornstarch is used in bleaching flour. The maximum amount used as a flour bleaching agent is 50 mg/kg.  Benzoyl peroxide has been evaluated in the 7^th JECFA meeting to an unconditional acceptance zone at 0 – 40 mg/kg and conditional acceptance level of 40 – 75 mg/kg for treatment of flour to be consumed by man (WHO, 1964).

It has been reported that benzoyl peroxide is typically used in the cheese manufacture at a level of 20 mg/kg to bleach milk used for the production of white Italian cheeses (Asiago fresh, Asiago soft cheese, Asiago medium cheese, Asiago old cheese, Blue cheese, Caciocavallo siciliano cheese, Gorgonzola cheese, Parmesan and Reggiano cheese, Provolone cheese, Romano cheese, Swiss and Emmental cheese) (U.S. FDA, 2003b). The FDA has affirmed benzoyl peroxide to be GRAS when used as a bleaching agent, following current GMP conditions of use, for the above-mentioned foods (U.S. FDA, 2003a).

Benzoyl peroxide is also used as a bleaching agent  in annatto-coloured whey processing.  Annatto and carotenoid pigments are used as colouring agents in making of numerous cheese products. Approximately 15% of the annatto added to the cheese milk remains in the whey. The colour may be highly objectionable in subsequent dried whey applications when the desired final product is white.  Therefore, a method to decolourize whey is required in order to maximize the usage possibilities for whey product.    Such that the final bleached product conforms to the descriptions and specifications for whey, concentrated whey, or dried whey (Barnicoat, 1937, Carrie, 1938).

McDonough et al. (1968) reported that  the effectiveness of bleaching depends on the concentration of benzoyl peroxide applied, the method of application, the holding time, and the temperature at which the treatment is given.   The rate and extent of de-colourization of whey by benzoyl peroxide were increased as the temperature was raised from  3.2°C to 63°C. However, there was no additional increase at 74°C and protein denaturation was evident. It was recommended the use of 20 mg/kg of benzoyl peroxide for one hour at 60-63 °C. After the bleaching treatment the whey is ready for concentration and drying without additional treatment. The oxidized flavor present after treatment will disappear during drying of the whey.  The dairy industry recommended treatment conditions for bleaching whey with benzoyl peroxide is 20 mg/kg of benzoyl peroxide at 60°C for 15 minutes at pH 6 to 7. In general, the lower the temperature, the longer the contact time and the higher dose needed to get the same degree of bleaching (Oxylite, 2001).

Reactions and Fate in Foods

Benzoyl peroxide in foods might possibly result of three secondary deleterious effects which include:1) the formation of harmful degradation products of benzoyl peroxide; 2) the destruction of essential nutrients; and 3) the production of toxic substances from the food components (Life Science Research Office, LSRO, 1980).

6.1 Degradation products of benzoyl peroxide

Benzoyl peroxide in food is almost completely (>  91%) converted to benzoic acid during processing. The benzoic acid content of the treated food would increase roughly equal to the benzoyl peroxide employed. The direct addition of benzoic acid and sodium benzoate to food is approximately two to three times this amount (Subcommittee on Review of the GRAS List, Subcommittee on GRAS, 1972). Furthermore, benzoic acid is naturally found in fruits, spices, milk products, meats, and beverages (Van Straten, 1977).

 

6.2 Destruction of essential nutrients

Bleaching of cheese milk during summer months with benzoyl peroxide effectively destroys the high level carotenoid pigments of this milk and affords a means of controlling the colour of cheese. To make-up for the reduced vitamin A activity of the bleached milk, it requires in some countries that sufficient vitamin A should be added to the curd to compensate for the vitamin A or its precursors destroyed in the bleaching process. (U.S. FDA, 2003b). Vitamin A itself seems little affected by the normal bleaching process. Sharratt et al. (l964) observed an increased incidence of testicular atrophy  among rats receiving flour treated with high levels of benzoyl peroxide. They attributed these changes to a destruction of α-tocopherol, although no chemical-specific analyses were performed. Thus, conventional bleaching of flour and milk may destroy some  α-tocopherol.

However, the α-tocopherol content of both foods is relatively small (Lampert, 1975; Ockerman, 1978), so that its destruction would seem to have little nutritional significance. The oxidation of essential fatty acids represents another possible deleterious effect of benzoyl peroxide. Witten and Holman (1952) speculated that a pro-oxidant (benzoyl peroxide) might interfere with the normal metabolic conversion of linoleic and linolenic acids.  The amounts of unsaturated fatty acids in flour were not reduced by treatment with benzoyl peroxide and no difference from  untreated flour of unsaturated fatty acids could be detected. (Fisher et al., 1958).  No data are available on the fate of other essential nutrients, i.e. ascorbic acid, thiamin, riboflavin, and pyridoxine and methionine, in foods bleached with benzoyl peroxide. 

6.3 Further reactions with food components

Benzoyl peroxide can possible react with various constituents in food to produce potentially some of oxidation products. Such products have not been detected or identified in foods treated with benzoyl peroxide, so their existence and significance are entirely speculative at this time (LSRO, 1980). The unsaturated fatty acids and sterols would likely to undergo oxidation when treated with benzoyl peroxide. It was found that the addition of 333 mg/kg of benzoyl peroxide caused no perceptible diminution in the concentrations of linoleic, linolenic, or arachidonic acids present in flour (Fisher et al., 1958).  No data are available on the nature or likelihood of sterol oxidation products resulting  from food treatment with benzoyl peroxide. The production of significant amounts with current or anticipated uses of benzoyl peroxide as a bleaching agent in food seems unlikely. Smith and Kulig (1976) obtained a yield of 0.2% cholesterol (a) oxide upon treatment of cholesterol (1 mg/ml) for 6 hours at 50°C with 0.015% hydrogen peroxide. Milk used in the production of certain cheeses is treated with 20 mg/kg benzoyl peroxide.  If this benzoyl peroxide solution were as effective as the stronger hydrogen peroxide preparation, about 0.2 mg cholesterol (a) oxide per liter of milk would be produced by this treatment.

7 Food Categories and use levels 

When benzoyl peroxide is used as a bleaching agent, it reacts with the oxidizable substance present, such as annatto and carotenoid pigments, and is itself converted to benzoic acid in the process. The rate of conversion increases with temperature. The final whey powder product should contain no measurable amounts of benzoyl peroxide, all of it having been converted to benzoic acid. The rate of decomposition of benzoyl peroxide in whey followed first-order kinetics where the speed depended on the size of the benzoyl peroxide particles and the agitation velocity. The pH of whey had little effect on the decomposition rate of benzoyl peroxide (Chang et al., 1977). Also, they found that, after reaction with whey, 91.7% of the radioactive labeled [14C] benzoyl peroxide was recovered as benzoic acid. Minor amounts of hydroxyl benzoic acids, phenyl benzoate, phenol, and benzoyl peroxide were also found. In addition, about 6.84% of the radioactive label was tightly bound to non dialyzable whey components and about 0.6% was bound to dialyzable neutral components of whey. The entire bound-label was recovered as benzoic acid after extraction.

Similarly, it has been shown that the greater part of benzoyl peroxide added to flour decomposes into benzoic acid within a few days of treatment (Saiz, 2001). In its 7th report JECFA recognized the transformation of benzoyl peroxide to benzoic acid in flour bleaching treatment and baking (WHO, 1964). The committee considered the acceptability of small amount of benzoic acid in bread and the possible effects of the oxidative treatment on the flour.

They approved the use of benzoyl peroxide in flour and gave an unconditional acceptance level of 0 - 40 mg/kg. During the 55th JECFA meeting (2000), benzoyl peroxide was re-evaluated as a bleaching agent in flour and JECFA concluded that treatment of flour at concentrations of 40 mg/kg was acceptable (WHO, 2001). As regard to the current  regulatory approvals for benzoyl peroxide in some countries, BP is currently approved by the U.S. FDA as a Generally-Recognized-As-Safe (GRAS) substance in USA. This ingredient maybe used at GMP levels in flour, milk used to make Italian cheeses and annatto-coloured whey, concentrated whey and dried whey. In Australia and New Zealand, the Food Standards for Australia and New Zealand has approved BP as a bleaching agent in all foods at the maximum level of 40 mg/kg (measured as benzoic acid). In Canada, the Canadian Food and Drug Regulations permit BP in liquid whey destined for the manufacture of dried whey products other than those for use in infant formula to decolourize whey at the maximum use level of 100 mg/kg (Canadian Department of Health, CDH, 2003)

ikhsan : http://www.fao.org/fileadmin/templates/agns/pdf/jecfa/cta/63/Benzoylperoxide.pdf

SERBA SERBI TENTANG GANDUM

Pokok Gandum (bahasa Inggeris: wheat) tergolong dalam famili rumput dan merupakan tanaman bijian yang kedua terbesar selepas jagung; ketiganya adalah padi. Nama botaninya Triticum spp. Bijiran gandum merupakan makanan ruji yang digunakan bagi menghasilkan tepung. Sekamnya boleh dipisahkan dan dihancurkan menjadi bran. Gandum juga ditanam khusus untuk tanaman ragut bagi ternakan dan untuk menghasilkan jerami.

Gandum yang ditanam bermula di [Asia Barat Daya]] di kawasan yang kini dikenali sebagai "Sabit Subur" (bahasa Inggeris: Fertile_crescent). Bukti cari gali tertua bagi penanaman gandum datangnya dari Syria, Jordan, Turki, Armenia, dan Iraq. Sekitar 9,000 tahun dahulu, Gandum Einkorn ("einkorn" dalam bahasa Jerman membawa maksud harfiah "satu butir") liar dituai dan ditanam dalam apa yang telah dikatakan bukti arkeologi pertama pertanian di Sabit Subur. Sekitar 8,000 tahun dahulu, melalui mutasi berlaku dalam Gandum Emmer yang menghasilkan tumbuhan dengan benih yang lebih besar, tetapi tidak mampu disebar oleh angin (sila lihat Pertanian). Walaupun tumbuhan ini tidak mampu hidup meliar, Gandum Emmer telah menghasilkan lebih banyak makanan bagi manusia, berbanding gandum yang lain. Dalam ladang yang ditanam, pokok Gandum Emmer telah mengatasi tumbuhan lain yang mempunyai biji benih lebih kecil yang mampu bercambah sendiri, dan menjadi leluhur bagi jenis gandum moden. Leluhur liar Triticum turgidum dicoccoides (Körn.), salah satu bentuk Gandum Emmer (Triticum turgidum dicoccum (Schrank.)) tanaman yang terawal, telah dijumpai di kawasan Palestin oleh Aaron Aaronsohn pada tahun 1906. Penanaman gandum mulai tersebar ke Eropah pada permulaan Zaman Neolitik.

Genetik dan penanaman gandum.

Genetik gandum adalah lebih rumit berbanding genetik haiwan ternakan. Sebilangan spesies gandum merupakan poliploidi yang stabil, dan mempunyai lebih daripada dua set kromosom diploid. Banyak jenis gandum tidak berbeza hanya dari segi genom tetapi juga dalam bilangan genom yang dipunyai. Empat daripada lima jenis gandum yang paling biasa adalah hasil pengacukan. Gandum Einkorn adalah baka diploid (2x kromosom) yang boleh dianggap sebagai "leluhur" gandum. Gandum Einkorn menghibridkan dengan rumput diploid liar (Triticum speltoides, Triticum tripsacoides, atau Triticum searsii) untuk membentuk baka tetraploid (4x kromosom), iaitu Gandum Emmer dan Gandum Durum. Gandum Emmer dan Gandum Durum pula menghibridkan dengan lagi sejenis rumput diploid liar (Triticum tauschii) untuk menghasilkan baka heksaploid (6x kromosom), iaitu Gandum Spelta (Triticum spelta) dan Gandum Biasa (gandum yang digunakan untuk membuat roti). Adakah Gandum Emmer dihibridkan secara semula jadi ataupun dengan senjaga merupakan satu persoalan yang dapat dipertikaikan. Pengacukan kedua-dua leluhur Gandum Emmer memerlukan mutasi penduaan kromosom yang merupakan satu mutasi yang tidak boleh kekal secara semula jadi melebihi beberapa generasi. Kesemua kejuruteraan genetik (pengacukan) ini dilakukan beribu-ribu tahun dahulu oleh petani kuno yang tidak sedar akan genetik moden atau kesulitan untuk menghibridkan tumbuhan-tumbuhan poliploidi.

Kultivar

Terdapat banyak sistem pengelasan taksonomi yang telah digunakan untuk spesies gandum, dan nama yang digunakan bagi setiap spesies gandum dalam sesuatu sumber maklumat mungkin berbeza dengan nama yang digunakan oleh sumber maklumat yang lain. [1] Kultivar gandum dikelaskan mengikut:

musim bertumbuh, umpamanya gandum musim sejuk lawan gandum musim bunga; dan

kandungan gluten, umpamanya gandum keras (kandungan gluten yang tinggi) atau gandum lembut (kandungan kanji yang tinggi).

Statistik penghasilan dan penggunaan Guni gandum

Pengeluaran gandum sejagat berjumlah 624 juta tan pada tahun 2004, dengan pengeluar gandum terbesar merupakan:

China: 91.3 juta tan

India: 72 juta tan

Amerika Syarikat: 58.8 juta tan

Persekutan Rusia: 42.2 juta tan

Perancis: 39 juta tan

Jerman: 25.3 juta tan

Australia: 22.5 juta tan

Pada tahun 1997, penggunaan gandum per kapita di seluruh dunia ialah 101 kilogram, didahului oleh Denmark dengan 623 kilogram.


Untuk tujuan pasaran komoditi, bijirin gandum yang dituai dikelaskan mengikut ciri-ciri bijirin. Pembeli gandum menggunakan ciri-ciri ini untuk memutuskan jenis gandum yang dibeli kerana setiap kelas mempunyai kegunaan khusus. Penghasil gandum pula menggunakan sistem ini untuk menentukan kelas gandum yang lebih menguntungkan untuk ditanam. Gandum banyak ditanam sebagai tanaman kontan disebabkan hasil yang baik dari segi keluaran setiap ekar. Tambahan pula, pokok gandum tumbuh dengan mudah dalam cuaca serdahana walaupun musim tumbuh pendek sahaja, dan menghasilkan tepung yang bermutu tinggi untuk kegunaan-kegunaan yang meluas. Kebanyakan roti dihasilkan menggunakan tepung gandum, dengan banyak roti dinamakan sempena bijiran lain yang terdapat dalamnya, termasuk roti rai dan oat. Banyak makanan popular yang lain juga diperbuat daripada tepung gandum, dan menyebabkan permintaan bijiran gandum yang besar, termasuk ekonomi yang mempunyai lebihan makanan. 

Gandum boleh dikelaskan kepada dua pembahagian utama, walaupun setiapnya merangkumi beberapa subbahagian. Yang pertama merangkumi kesemua kepelbagaian gandum merah. Pembahagian kedua merangkumi kesemua kepelbagaian gandum putih yang boleh dipecahkan lagi kepada bersekam tebal dan bersekam nipis. Gandum jenis bersekam tebal ditanam secara meluas sebelum 1799, kerana jenis ini menghasilkan tepung terbaik dan pada musim kering, jenis ini menghasilkan sama banyak dengan jenis berkulit nipis. Bagaimanapun, jenis bersekam tebal lebih mudah dijangkiti kulapuk, sementara jenis bersekam nipis lebih lasak, dan secara umumnya lebih tahan kulapuk. Dengan itu, akibat serangan kulapuk yang meluas pada 1799 memulakan peralihan perlahan-lahan kepada penanaman gandum jenis bersekam tebal.

ikhsan wiki...