Can you summarize the following document?
        
  卡拉膠是一種無臭、無味的大型(分子量在10萬道爾頓以上)的高度彈性分子,相互捲曲在一起形成雙螺旋結構。卡拉膠具有親水性、粘性、穩定性,溶於80攝氏度熱水形成粘性透明液體,並能在室溫下形成不同形式的凝膠。這使食品工業及其他產業亦廣泛使用卡拉膠作增稠劑及穩定劑。  All carrageenans are high-molecular-weight polysaccharides made up of repeating galactose units and 3,6 anhydrogalactose (3,6-AG), both sulfated and nonsulfated. The units are joined by alternating α-1,3 and β-1,4 糖苷鍵。

  商業應用的卡拉膠以下列三個型別為主:  影響到這三個型別卡拉膠在其特質上的主要差異在於其硫酸酯在重複性半乳糖單位的位置與數量。

  

  下面是卡拉膠應用的一些例子:

  In the U.S., carrageenan is allowed under FDA regulations as a direct food additive and is considered 公認安全 when used in the amount necessary as an emulsifier, stabilizer, or thickener in foods, except those standardized foods that do not provide for such use. FDA also reviewed carrageenan safety for infant formula. The European Food Safety Authority concluded "there is no evidence of any adverse effects in humans from exposure to food-grade carrageenan, or that exposure to degraded carrageenan from use of food-grade carrageenan is occurring", Furthermore, the Joint FAO/WHO expert committee on food additives stated in a July 2014 review of carrageenan "that the use of carrageenan in infant formula or formula for special medical purposes at concentrations up to 1000 mg/L is not of concern".  Although the National Organic Program (NOP) had added carrageenan to its National List of additives allowed to be included in organic foods in 2003, and reviewed and reauthorized it in 2008, noting it as "critical to organic production and handling operations", on November 18, 2016 the NOP's National Organic Standards Board (NOSB) voted to recommend carrageenan be removed from the National List of additives allowed in organic food production.  On April 4, 2018 the Agricultural Marketing Service (AMS) (美國農業部) published a document to announce the renewal of carrageenan on the National List, allowing its continued use in food products. The document states, “The NOSB recommended removing carrageenan because they determined that alternative materials, such as gellan gum, guar gum, or xanthan gum, are available for use in organic products” continuing, “AMS found sufficient evidence in public comments to the NOSB that carrageenan continues to be necessary for handling agricultural products because of the unavailability of wholly natural substitutes (§ 6517(c)(1)(ii)). Carrageenan has specific uses in an array of agricultural products, and public comments reported that potential substitutes do not adequately replicate the functions of carrageenan across the broad scope of use. Therefore, carrageenan continues to meet the OFPA criteria for inclusion on the National List.” The rule went into effect May 29, 2018.  In the most recent review by an independent panel, the Joint Expert Committee of the 聯合國糧食及農業組織 of the 聯合國 and 世界衛生組織 on Food Additives released a technical report in 2015 on the use of carrageenan in 配方奶粉 and found that the additive was ‘not of concern’ in infant formula as food for special medical purposes at concentrations up to 1000 千克s per 升. The use of carrageenan in infant formula, organic or otherwise, is prohibited in the EU for precautionary reasons, but is permitted in other food items.  In the UK, the Food Standards Agency issued a product recall for sweets containing carrageenan, stating that carrageenan “is not permitted as an ingredient in jelly confectionery products as it presents a choking hazard”.

  Degraded carrageenan (poligeenan) has been found to cause inflammation of the gut, altering microbiota, and was found to be a triggering factor of inflammatory bowel diseases such as ulcerative colitis and Crohn Disease.  Food-grade carrageenan has been confused with poligeenan, although they are completely different products, creating a controversy over the food-additive's safety. Food-grade carrageenan's safety has been proven through various studies.
卡拉膠(英語:Carrageenans 或 英語:carrageenins;,CAS 9000-07-1),又稱鹿角菜膠、角叉菜膠、愛爾蘭苔菜膠,是一組從海洋可食用紅藻(包括角叉菜屬、麒麟菜屬、杉藻屬及沙菜屬等)中提取的線性硫酸化多糖的統稱。這些多糖體由於能夠與食物中的蛋白質穩定結合,所以被廣泛應用於食品產業,例如:作為凝固劑、增稠劑或穩定劑,用於奶類及肉類產品。