關華豆膠

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關華豆膠
识别
CAS号 9000-30-0
ChemSpider NA
ATC代码 A10BX01
性质
pKa 5-7
危险性
MSDS MSDS
若非注明,所有数据均出自一般条件(25 ℃,100 kPa)下。

關華豆膠(Guar gum),也叫做 瓜爾膠(guaran),是一種半乳甘露聚醣( galactomannan)。CAS登録號碼是9000-30-0。它主要是瓜爾豆的胚乳。瓜爾豆種子去殼,碾磨和篩選取得瓜爾豆膠。[1] 它通常是一種可自由流動的灰白色粉末。

特性[编辑]

  • 分子量在20~30萬的時候,有血糖値上昇抑制作用、以及降低膽固醇、使排便更順暢等等的生理效果。
  • 可被認可的食品添加物,廣泛用於增稠劑、安定劑。下列產品,幾乎都有使用,例如:冰淇淋、和菓子、海鮮煉製品、沙拉醬等等。還有,利用瓜爾豆酵素處理的豆酵素分解物中有水溶性食物繊維。

生產與交易[编辑]

瓜爾豆(關華豆)主要生長在印度和澳大利亞,在美國,中國和非洲的小作物。在印度古吉拉特邦(Gujarat)、拉賈斯坦邦(Rajasthan)、和哈里亞納邦(Haryana)是主要種植區,而主要交易市場是在 Rajasthan 的三個轄區,轄區如下:JodhpurSri GangaNagarHanumangarh

印度每年生產10.0-12.5萬盧比噸(1 - 125萬噸)瓜爾,使印度成為最大的生產國,約佔世界總產量的80%。而在巴基斯坦,旁遮普邦是其瓜爾豆主產區。

瓜爾膠及其衍生物是世界總產量的約7萬盧比噸(700,000噸)。工業用瓜爾豆膠約佔總需求量的45%左右。它是用來作為在鑽油井中的控制劑,以方便的鑽井和防止流體損失。

在2012年,瓜爾豆價格增長了9倍至10倍。主要原因是,由於拉賈斯坦邦持續乾旱,瓜爾豆膠的短缺陷入恐懼之中,導致哈里伯頓公司之前建立的庫存產生大規模的價格上漲。

屬性[编辑]

化學式[编辑]

Guaran.svg

在化學上,關華豆膠是糖半乳糖和甘露糖組成的多醣。其基質是由一個 半乳糖和β 1,4-連結的兩個甘露醣基團相互連接的線性鏈,形成短邊分支機構。

溶解度和粘度[编辑]

關華豆膠相較於刺槐豆膠有更好的水溶性,由於關華豆膠有較多的半乳糖支鍊,同時也是較好的安定劑。和刺槐豆膠不同,關華豆膠並不會自己形成凝膠。[2] 然而使用硼砂或者可以使關華豆膠產生交聯 (Cross-linking)使其形成凝膠。在水中關華豆膠是非離子性的水狀膠體,並不會因為離子強度pH值的改變造成結構或者性質產生變化。一般而言,在pH值介於5到7時關華豆膠結構仍然能保持穩定。但在極端的酸性或者溫度下 (如pH = 3且溫度為50 °C時)[2]關華豆膠可能會被降解。強酸會導致其水解並且使其黏度下降,而在高濃度強鹼下年度也會降低。另外,關華豆膠無法溶於大部分的有機溶劑。

Guar gum shows high low-shear viscosity but is strongly shear-thinning. It is very thixotropic above 1% concentration, but below 0.3%, the thixotropy is slight. It has much greater low-shear viscosity than that of locust bean gum, and also generally greater than that of other hydrocolloids. Guar gum shows viscosity synergy with xanthan gum. Guar gum and micellar casein mixtures can be slightly thixotropic if a biphase system forms.[2][3]

增稠[编辑]

關華豆膠的增稠效果比玉米澱粉高出接近八倍,經濟效益更為突出。添加少量即可產生足夠的黏度。因此也在很多較多相的配方中扮演重要角色:關華豆膠可以當作乳化劑使用,可以防止油滴聚集;也可以做為安定劑來防止顆粒物質沉澱。

Ice crystal growth[编辑]

Guar gum retards ice crystal growth nonspecifically by slowing mass transfer across the solid/liquid interface. It shows good stability during freeze-thaw cycles.[2]

分級[编辑]

關華豆膠分析如下:

Test Test Method Test Test method
Colour TP/09 Acid-insoluble residue TP/115
Viscosity TP/10/04 Fat content TP/18
Granulation (mesh) TP/21 Ash content TP/12
Moisture, pH TP/1 and TP/29 Gum content TP/03
Protein TP/05 Heavy metals TP/13
Insolubles Ash TP/11 Filterability TP/20A

Guar gum powder standards are:

  • HS-Code- 130 232 30
  • CAS No.- 9000-30-0
  • EEC No.- E 412
  • BT No.- 1302 3290
  • EINECS No. - 232-536-8
  • Imco Code- Harmless

製造過程[编辑]

根據最終產品的要求後,使用各種處理技術。瓜爾豆膠的商業化生產,通常採用焙燒、差分減員、過篩、和拋光。

Food-grade guar gum is manufactured in stages. Guar split selection is important in this process. The split is screened to clean it and then soaked to prehydrate it in a double-cone mixer. The prehydrating stage is very important because it determines the rate of hydration of the final product.

The soaked splits, which have reasonably high moisture content, are passed through a flaker. The flaked guar split is ground and then dried. The powder is screened through rotary screens to deliver the required particle size. Oversize particles are either recycled to main ultra fine or reground in a separate regrind plant, according to the viscosity requirement.

This stage helps to reduce the load at the grinder. The soaked splits are difficult to grind. Direct grinding of those generates more heat in the grinder, which is not desired in the process, as it reduces the hydration of the product. Through the heating, grinding, and polishing process, the husk is separated from the endosperm halves and the refined guar split is obtained. Through the further grinding process, the refined guar split is then treated and converted into powder.

The split manufacturing process yields husk and germ called “guar meal”, widely sold in the international market as cattle feed. It is high in protein and contains oil and albuminoids, about 50% in germ and about 25% in husks. The quality of the food-grade guar gum powder is defined from its particle size, rate of hydration, and microbial content. E412 guar gum is an important natural food supplement with high nutritional value.[來源請求]

Manufacturers define different grades and qualities of guar gum by the particle size, the viscosity generated with a given concentration, and the rate at which that viscosity develops. Coarse-mesh guar gums will typically, but not always, develop viscosity more slowly. They may achieve a reasonably high viscosity, but will take longer to achieve. On the other hand, they will disperse better than fine-mesh, all conditions being equal. A finer mesh, such as a 200 mesh, requires more effort to dissolve.[4]

Modified forms of guar gum are available commercially, including enzyme-modified, cationic and hydropropyl guar.[5]


工業用途[编辑]

  • 紡織工業(sizing, finishing and printing)
  • 造紙工業([improved sheet formation, folding and denser surface for printing)
  • 製藥生技工業([as binder or as disintegrator in tablets; main ingredient in some bulk-forming laxatives)
  • 化桩品化學工業([thickener in toothpastes, conditioner in shampoos (usually in a chemically modified version))
  • 火藥工業(Explosives industry –as waterproofing agent mixed with ammonium nitrate, nitroglycerin, etc.)
  • 油田、天然氣田
  • 採礦工業(Mining)
  • Hydraulic fracturing Shale oil and gas extraction industries consumes about 90% of guar gum produced from India and Pakistan. [6]
  • Hydroseeding – formation of seed-bearing "guar tack"[7]
  • Medical institutions, especially nursing homes - used to thicken liquids and foods for patients with dysphagia
  • Fire retardant industry - as a thickener in Phos-Chek
  • Nanoparticles industry - to produce silver or gold nanoparticles, or develop innovative medicine delivery mechanisms for drugs in pharmaceutical industry.

食品中的應用[编辑]

瓜爾豆膠的最大市場是在食品工業。在美國,各種食品中的應用,設置為不同百分比的其允許濃度。[8] 在歐洲,瓜爾豆膠的歐盟食品添加物號碼是E412。Xanthan gum and guar gum are the most frequently used gums in gluten-free recipes and gluten-free products.

應用領域包括:

  • 在焙烤食品, it increases dough yield, gives greater resiliency, and improves texture and shelf life; in pastry fillings, it prevents "weeping" (syneresis) of the water in the filling, keeping the pastry crust crisp. It is primarily used in hypoallergenic recipes that use different types of whole-grain flours. Because the consistency of these flours allows the escape of gas released by leavening, guar gum is needed to improve the thickness of these flours, allowing them to rise as a normal flour would. [9]
  • 奶製品,it thickens milk, yogurt, kefir, and liquid cheese products, and helps maintain homogeneity and texture of ice creams and sherbets. It is used for similar purposes in plant milks.
  • 至於肉類,它的功能作為粘合劑。
  • In condiments, it improves the stability and appearance of salad dressings, barbecue sauces, relishes, ketchups and others.
  • 罐頭湯,它是用來作為增稠劑穩定劑
  • It is also used in dry soups, instant oatmeal, sweet desserts, canned fish in sauce, frozen food items, and animal feed.

營養與藥用功效[编辑]

關華豆膠(瓜爾豆膠), 是一種可溶於水的可溶性纖維,acts as a bulk-forming laxative, so is claimed to be effective in promoting regular bowel movements and relieving constipation and chronic related functional bowel ailments, such as diverticulosis, Crohn's disease, colitis and irritable bowel syndrome.

Several studies have found significant decreases in human serum cholesterol levels following guar gum ingestion. These decreases are thought to be a function of its high soluble fiber content.[來源請求]

Guar gum has been considered of interest in regard to both weight loss and diabetic diets. It is a thermogenic substance.[10] Moreover, its low digestibility lends its use in recipes as a filler, which can help to provide satiety, or slow the digestion of a meal, thus lowering the glycemic index of that meal. In the late 1980s, guar gum was used and heavily promoted in several weight-loss products. The US Food and Drug Administration eventually recalled these due to reports of esophageal blockage from insufficient fluid intake, after one brand alone caused at least 10 users to be hospitalized, and a death.[11] For this reason, guar gum is no longer approved for use in over-the-counter weight loss aids in the United States. Moreover, a meta-analysis combining the results of 11 randomized, controlled trials found guar gum supplements were not effective in reducing body weight.[12]

Two Japanese studies using rats showed guar gum supports increased absorption of calcium occurring in the colon instead of in the small intestine. This means lesser amounts of calcium may be consumed to obtain its recommended minimum daily intake. This has obvious implications for reduced calorie diets, since some calcium-rich dairy products tend to be high in calories.[來源請求]

Guar gum, though, is also capable of reducing the absorbability of dietary minerals (other than calcium), when foods or nutritional supplements containing them are consumed concomitantly with it, but this is less of a concern with guar gum than with various insoluble dietary fibers.

Some studies have found guar gum to improve dietary glucose tolerance.[13] Research has revealed the water-soluble fiber in it may help people with diabetes by slowing the absorption of sugars by the small intestine. Although the rate of absorption is reduced, the amount of sugar absorbed is the same overall. This may help diabetic patients by moderating glucose "spikes".

Allergies[编辑]

Some studies have found an allergic sensitivity to guar gum developed in a few individuals working in an industrial environment where airborne concentrations of the substance were present. In those affected by the inhalation of the airborne particles, common adverse reactions were occupational rhinitis and asthma.[14]

Soy protein occurs as an impurity in manufactured guar gum, and can make up as much as 10%. The guar gum can therefore adversely affect those with sensitivity to soy.[15]

Dioxin contamination[编辑]

In July 2007, the European Commission issued a health warning to its member states after high levels of dioxins were detected in a food additive - guar gum - used as thickener in small quantities in meat, dairy, dessert or delicatessen products. The source was traced to guar gum from India that was contaminated with pentachlorophenol, a pesticide no longer in use.[16] PCP contains dioxins as contamination. Dioxins damage the human immune system.[17]

參考[编辑]

  1. ^ foa.org (PDF). [2011-04-18]. 
  2. ^ 2.0 2.1 2.2 2.3 Martin Chaplin "Water Structure and Behavior: Guar Gum". April 2012. London South Bank University
  3. ^ Lynn A. Kuntz. "Special Effects With Gums". December 1999. Food Product Design
  4. ^ foodproductdesign.com
  5. ^ Ashford's Dictionary of Industrial Chemicals, Third edition, 2011, page 4770
  6. ^ Ram Narayan. From Food to Fracking: Guar Gum and International Regulation. RegBlog. University of Pennsylvania Law School. August 8, 2012 [15 August 2012]. 
  7. ^ Product description: Guar Tack. S&S Seeds Inc. 2006. Ssseeds.com. [2011-04-18]. 
  8. ^ fda.gov- Food additive list
    Maximum Usage Levels Permitted- Guar gum
  9. ^ Source: NOW Foods. Guar Gum Nutrition Label. Bloomingdale, IL: n.p., n.d.
  10. ^ JC Brown & G Livesey. "Energy balance and expenditure while consuming guar gum at various fat intakes and ambient temperatures". Am J Clin Nutr. 1994. 60(6):956-64 (ISSN: 0002-9165)
  11. ^ Dietary Supplements: Making Sure Hype Doesn't Overwhelm Science (November 1993)
  12. ^ Pittler MH, "Ernst E. Guar gum for body weight reduction: meta-analysis of randomized trials". Am J Med. 2001;110(9):724-730.
  13. ^ Daumerie C, Henquin JC, "Acute effects of guar gum on glucose tolerance and intestinal absorption of nutrients in rats". Diabete Metab. 1982 Mar;8(1):1-5.
  14. ^ AllergyNet - Allergy Advisor Find. Allallergy.net. [2013-02-19]. 
  15. ^ Guar Gum And Soy Allergy. Livestrong.Com. [2013-02-19]. 
  16. ^ Commission Regulation (EU) No 258/2010. 2010-03-25 [2012-07-14]. 
  17. ^ Dioxins and their effects on human health. 2010-05-01 [2012-02-08].