Introduction on Dietary Fiber

The traditional definition of Dietary Fiber is a substance that can be found in plant cell wall and cells but cannot be dissolved by our digestive enzymes. Though containing the same carbohydrate composition as amylum, dietary fiber can not be digested and absorbed by our body because of its different linking, and will eventually be egested. In consequence, it was regarded previously as useless substance. Fibers in food, in general, can be divided into two groups: Insoluble Dietary Fiber (IDF) and Soluble Dietary Fiber (SDF); and the combination of these two is commonly known as Total Dietary Fiber (TDF). IDF, known as Crude Fiber in Traditional Nutrients Table, includes: 1, Cellulose: a glucose polymer, hydrophile but insoluble in water and common dissolvents; rich in raw gluten, whole wheat flour, beans, rootstalks, cabbage, cucumber, broccoli, and brussels sprout. 2. Hemicelluloses: complex polysaccharides with polyuronic acid, often found in algae, whole grain, gluten grain, and vegetables like mustard and brussels sprout. 3. Lignin: Often seen in woods, bamboos, straws, and old rootstalks. Hard to swallow, and is no longer referred to dietary fiber but plant fiber instead. Gums: a substance that will become tremellose and sticky when dissolved in water. Rich in –Glucan in oatmeal, barley, dried beans, plantain seeds and jelly fig. Pectin: a tremellose polysaccharide with a great water-holding capacity; rich in apples, citrus, persimmons, pears, bananas, strawberries, dried beans, broccoli, carrots, cabbage, pumpkin, and potatoes. Mucilage: a extremely sticky and water-holding polysaccharide, such as Alginic Acid in kelps, which can be found in algae and seeds and easily gets tremellose with water. The biggest difference between IDF and SDF lies in the water-holding capacity. SDF possesses a better capacity to hold water for the formation of normal excrements to be easily egested; therefore, SDF is more helpful for constipation improvement. In fact, recent nutrition studies reveal that, dietary fiber performs various functionalities in keeping our physical functions well and in disease control. Those functionalities include: In the mouth, it advances chewing movements and salvia secretion to stimulate facial muscles and gums for our oral health, especially for patients with periodontosis. In the stomach, dietary fiber (especially SDF) extends the time food remains in the stomach for a slower evacuation. Also, it helps us keep fit by providing us a sense of full and requiring more calories for the digestion when it swelled. In the duodenum, it helps us expel bile acid and cholate by combining itself with them, and to keep the consistency, the oxidation of cholesterols will happen in the liver to generate bile acid. That is, high-fiber diet can indirectly decrease cholesterol in the blood. Also, fat is dissolved and absorbed with bile by our body here while dietary fiber can prevent cholesterol from the absorption. Besides, food rich in fibers often contains less fat, and thus can not only help control blood fat but prevent modern chronic diseases, such as cardiovascular diseases, cerebrovascular accidents and high blood pressure. In the large intestine, with its water-holding capacity, dietary fiber can dilute cancerogenic toxicity generated from the intestine, advance the intestinal peristalsis and collect feces inside the body as excrements to be egested appropriately. Thus, it lowers the rate of constipation and colorectal cancer, along with the help to prevent hemorrhoid and appendicitis. Besides, it is also helpful for maintaining intestinal bacteria balance, preventing malignant bacteria. Researches indicate that, dietary fiber provides a vigorous growth of intestinal lactobacillus.The increase of probiotics with the decrease of malignant bacteria will definitely keep our body healthy. It can be therefore regarded as one prebiotics. Promoting the secretion of intestinal mucus that protects parietal cells from the invasion of harmful obstacles, it delays the absorption of polysaccharides, ease up the rise of blood sugar, reduce the secretion of insulin, and helps controlling and preventing diabetes. To sum up, the advantages of dietary fiber are: advances chewing movements to make food and salvia well mixed; extends evacuation time for stomach and small intestines for a sense of full; advances gastrointestinal peristalsis for regular defecation; suppresses the rise of blood sugar after diet; reduces fat in blood; absorbs organic substances and expel harmful ones; improves intestinal bacteria balance by increasing probiotics and decreasing malignant ones; absorbs bile acids and carcinogenic substances to be expelled; lowers absorbing rate of salts to lower blood pressure. Excess intake of dietary fiber, however, may result in some side effects, including: high fiber diet contains phytic acid that will interrupt the body absorption of Vitamin A & B, iron, zinc, calcium, magnesium and copper; it lowers the digestion and absorption of nutrients. (this is sometimes be thought as an advantage since most modern people are having overnutrition); Too much IDF content may cause mechanic friction to damage intestine wall, especially for infants; Too much lignin may cause constipation instead because of its overmuch absorption of water; it may cause diarrhea because that organic acids, generating from the combination of SDF and intestinal bacteria, would produce surfactant to excessively accelerate intestinal movements. American Dietetic Association (ADA) addresses the positive effects of dietary fiber on health, suggesting the public to intake enough amount dietary fiber from different vegetables and fruits. The suggested daily intake amount is 20 -35 grams for an adult and 25-40 grams for the children according to their age. The original definition of dietary fiber in the past was made only based on physical functions and analysis methods while it actually allows a much wider range for food components. And with the rapid development of modern technologies and food industry, lots of food components similar to dietary fiber, such as resistant starch, oligosaccharide and inulin, are not included in the definition of dietary fiber. The confinement in the old definition of dietary fiber is becoming clearer. Furthermore, people’s awareness of its important physical functions brings out a plenty of dietary fiber foods. Eventually, American Association of Cereal Chemists (AACC) set up a committee specific for the definition of dietary fiber in 1998. And on June 23rd, 1999, AACC and the International Life Sciences Institute (ILSI) together established an enforcing committee. What is more, a specific seminar for the definition of dietary fiber was held in the annual meeting of the Institute of Food Technologists (IFT) in Chicago on July 26th, 1999, and the same year, a discuss was made in the 84th AACC annual meeting with a final definition of dietary fiber concluded as followed: Dietary fiber is a vegetable component for diet that cannot be absorbed by small intestines in human body, but can be fermented partly or completely by large intestines. It is a combination of carbohydrate and other similar substances, including polysaccharides, oligosaccharides, Lignin, and related vegetable substances. Dietary fiber provides one and more physical functions, like constipation releasing, blood sugar control, and the decrease of blood fat. The above description explicitly defines dietary fiber as a edible vegetation composition but not organic composition. And its main components are: celluloses, hemicelluloses, pectin; soluble colloids, like gums and algae polysaccharides; lignin in plant cell wall; indigestible substances, like resistant starch, resistant dextrin, modified celluloses, mucilage, oligosaccharides; and a few related components, like waxes, cutin, and suberin. Chitin and chitosan are organic aminopolysaccharides, while some scholars insist that they should be defined as dietary fiber because of their special structures. Similar to the fiber, both are constructed with straight chain polymer, a composition of 1000 – 3000 n- Acetyl -d –Glucosamine morphons in a B-1,4 chain. Straight chain polymer is a natural and digestible polymer without toxicity, so as to be regarded as the organic polymer with most potential. In the nature, chitin is the most common aminopolysaccharide next to fiber, and can be generally found on the shell of invertebrates like insects and aquatic crustacean, and also on the cell wall of fungus. Its main functions in organics are to support body structure as skeletons and to provide protection. Chitosa is the product after the deacetylation of chitin. As a rule, a merely 70 % completion of the deacetylation on chitin can turns it into chitosa, soluble in acid.

Meat Analogue (Artificial Meat)

“ Consumer prices are rising in China….University restaurants use vegetarian meat to pass off as pork….” This is another piece of news that reminds us of China’s black-hearted food products. However, behind this, food processing products of “ artificial meat “ is indirectly being wronged for mixing with fake products. Actually, artificial meat itself exits the positive meaning in terms of food processing skills, nutrition and health.

Artificial meat is not exactly a lovely name. Consumers prefer to call it “ vegetarian meat.” In the industry, “ meat analogue “ is the term used to refer to “ imitation meat “ made from the processing skills of making textured vegetable proteins. It is called “ imitation meat “ because it very much approximates the qualities of real animal muscle fiber (appearance and taste).

By definition, meat analogue is also called meat substitute, mock meat, faux meat , imitation meat or veat. Meat analogue is mock meat that is made from non-animal protein and its appearance and smell are very much like real meat. The market for non-meat food targets primarily on vegetarians. Of course, vegan, ovo-vegetarian, lacto-vegetarian and ovo-lacto vegetarian consumers are also included. The reasons for meat-less dietary, besides the religious factor, it also has something to do with the rise of emphasizing on vegetable protein, more and more consumers choose vegetable-protein products for health reasons. In early days, the motives for the Japanese to develop veggie ham were to use cheap vegetable protein as a substitute for animal-protein products which were severely lacked of during postwar times. Surimi is another kind of processed product using fish protein ( or other animal protein such as turkey) to imitate other animal-protein products ( such as mock crab, mock shrimp or non-meat hotdog).

Humans are not unfamiliar with mock meat producing skills and products. Traditional Taiwanese gluten products including veggie chicken, veggie ducks, veggie fish are basically in the category of mock-meat products. Even products made from mushroom stems, tofu and dried beans were great mock-meat products during early times when living goods and materials were severely short of. Recently, with the progress in processing skills, soy protein is successfully transformed into textured vegetable protein (TVP) under high temperatrue and high pressure through single-screw or twin-screw extrusion forming technologies. Not to mention it also helps promote the development of vegetarian meat in the market. Of course, vegetable protein which can be used for food processing is not limited to only soy protein, traditional wheat protein, other types of soy protein and mycoprotein which is derived from mocro-organism fermentation are good materials for vegetable meat research & develoepment and relevant product applications. The very common human non-digestive dietary fiber – konjac fiber products in the market for the past few years are another mock-meat products for consumers to choose from in terms of taste and health reasons.

What is Melamine?

By the end of 2006, a sharp growth of acute renal failure problems occurred in animals was observed. In a very short period of time, there were more than 140 thousand cases reported. The investigation has found a connection between all the renal failure cases and the food. The contaminated pet food products that caused serious renal problems share one thing in common — wheat gluten imported from China. This batch of wheat gluten contains melamine. According to FDA (US), the chemical bonding of melamine (1,3,5-Triazine-2,4,6-triamine；C3H6N6, the chemical structure is shown in figure 1) and Cyanuric acid (1,3,5-triazinane-2,4,6-trione, the chemical structure is shown in figure 2) yields crystalline substances which may cause acute renal failures in animals.

Melamine is a white, odorless, crystalline N-heterocyclic organic base which is commonly used in paint, building materials, paper-making and textile industries. Melamine boards/paper and dinnerware are made from thermoplastic melamine. In some countries in Asia, it is also used to make pesticides and plant fertilizers.

Figure 1, Chemical structure of Melamine	Figure 2, Chemical structure of Cyanuric acid	Figure 3, chemical structure of the bonding of melamine and cyanuric acid

Nitrogen found in melamine creates potential misreading in Chemical analysis of proteins. Some crooked businessmen added even more nitrogen-containing melamine to confuse the chemical test reading. The FDA has discovered that the pet food manufacturers and material providers in China have added more melamine to pet food materials such as wheat glutens and rice glutens and then claimed their pet food products containing higher proteins. However, melamine, predominately from petrochemical industries, is high in nitrogen. Human body does not digest or break down melamine. If it is ingested in great amount, it may cause serious renal problems and may be lethal. It is no surprise to many that the products imported from China (PRC), in past few years, have aroused food safety concerns.

Melamine is actually a raw material for industrial use. The US has banned the use of melamine in human and animal food products. FDA claimed that there is no direct evidence to prove the connection of renal problems and ingestion of potentially contaminated chicken or pork. However, this does not put consumers at ease when it comes to the use of soybean or wheat gluten in food safety and the health concerns. The banning of melamine use in food products is still valid. FDA (US) has started the inspection of manufacturers’ production equipments and protein ingredients. I-Mei Foods Co. Ltd. follows rigorous ISO 9001 and GMP standards to manufacture soybean protein product line (i.e. imitation meat products for vegetarians). This provides consumers quality food and rid of food safety worries.

Some terms may be easily confused with melamine are melanin and melatonin. Melanin is the black pigment appears in human hair and skin. Melatonin is an endocrine produced by the pineal gland in human brain. It is also an anti-oxidant. Melatonin is able to hold the black pigments around the nucleus in human cells so the black pigment will not show through skin; hence, this makes the skin tone lighter. It is also used in sleep pattern regulations and eases the jet-lag syndromes found on some individuals.

Sumber : http://www.taiwannews.com.tw/static/admilk/news/961113/index_en.html