Plant Yielding Sugars, Starches, and Cellulose Product

What is Sugar?

• Sugars are an essential product of green plants, synthesized through photosynthesis and found in all plant tissues in varying quantities. However, most of the sugar produced by plants is immediately used in their metabolic processes, leaving only small amounts for storage. Storage sugars are commonly accumulated in different parts of plants, including roots, stems, flowers, bulbs, and fruits. Examples of plants with stored sugars include beets, carrots, and parsnips (roots), sugar cane, maize, and sorghum (stems), the palm tree (flowers), onions (bulbs), and many fruit varieties.
• There are several types of sugar, each serving specific roles in plants. The most notable forms are sucrose, glucose, and fructose. Sucrose, also known as cane sugar, is a common storage sugar, while glucose (grape sugar) and fructose (fruit sugar) are key sources of energy. These sugars not only support the plant’s growth and function but also act as a reserve food supply, enabling the plant to thrive in varying environmental conditions.
• For humans, sugar is not merely a luxury food item used for flavoring; it is an essential energy source. Its ability to be easily absorbed by the body makes it highly efficient for energy production, particularly after periods of physical exertion. While sugar is primarily consumed as a food, its extraction, purification, and refinement have led to the establishment of a vast global industry, elevating sugar beyond its biological importance into a major economic commodity.
• In terms of global significance, sugar ranks as one of the most valuable plant-based products, only surpassed by staples like wheat, corn, rice, and potatoes. Annually, over 30 million tons of sugar are produced worldwide, with an estimated value of $1.5 billion. Despite its significance, the number of plants used to commercially extract sugar is relatively limited. Key sources include sugar cane, sugar beet, sugar maple, maize, sorghum, and a few varieties of palm trees, all of which store sucrose as the primary type of sugar.
• The role of sugar, both in plant biology and human nutrition, underscores its importance as a vital energy resource and a crucial industrial product.

Sugars Yielding Plants

Sugars Yielding Plants

The study of plants that yield sugars highlights key species cultivated for their sugar content, spanning tropical and temperate regions. These plants, which vary in terms of geography and method of cultivation, form the foundation of sugar production across the globe. Here is a detailed look at the primary sources of sugar:

1. Sugar Cane (Saccharum officinarum)
   • Origin and Distribution: Sugar cane is a tall grass originating from Southeastern Asia or the East Indies. It spread to Egypt by 641 A.D. and Spain by 755 A.D., reaching the Americas through the Spanish and Portuguese in the early 1500s. The plant thrives in tropical and subtropical regions with high rainfall and temperatures above 80°F.
   • Cultivation: Sugar cane is propagated using cuttings, which sprout after two weeks in warm, moist conditions. The plant is harvested between 10 to 20 months after planting, just as its flowers begin to fade. The lower portion of the cane is richest in sugar, and knives are typically used for cutting.
   • Processing: The cane is transported to mills, where it is crushed, and the juice is extracted and purified through filtration, coagulation, and clarification. The resulting product is boiled into a syrup, which crystallizes into raw sugar. By-products include molasses, used in food and alcohol production, and bagasse, used as fuel or for paper and wallboard production.
   • Global Production: Countries like Cuba, Brazil, and India lead in sugar cane production. The United States grows a smaller amount, primarily in Louisiana.
2. Sugar Beet (Beta vulgaris)
   • Origin and Spread: The sugar beet, a variety of the common beet, originated from the wild Beta maritima of Europe. Its potential as a sugar source was first realized in the late 16th century, and its commercial use began around 1800, with Napoleon promoting it during the British embargo.
   • Cultivation: Sugar beets grow in cooler climates with summer temperatures around 70°F. They require deep cultivation and thinning for optimal growth. The crop is harvested in the fall when the sugar content in the roots peaks.
   • Processing: The juice is extracted through a diffusion process, in which beet slices are heated in water. The juice is clarified by a process called carbonation, where lime and carbon dioxide remove impurities. It is then concentrated and crystallized in a manner similar to sugar cane processing.
   • Global Production: Germany leads the world in beet sugar production, with significant contributions from Russia, France, and the United States.
3. Sugar Maple (Acer saccharum)
   • Geographic Location: Sugar maple trees, native to northeastern North America, are tapped for their sap, which flows during early spring when temperatures fluctuate between freezing and mild during the day.
   • Traditional and Modern Methods: Indigenous peoples first discovered maple sap, and early settlers adopted the practice. Sap is collected through incisions made in the tree’s bark, and it is boiled down into syrup or sugar. Modern methods involve advanced evaporators, and larger operations may tap thousands of trees to produce syrup.
   • Decline and Resurgence: The maple sugar industry saw its peak in the 19th century but has declined due to competition from cane sugar. However, the demand for pure maple syrup is rising once again, with Vermont leading production.
4. Palm Sugar
   • Primary Species: Various palm species, including the wild date (Phoenix sylvestris), palmyra palm (Borassus flabellifer), and coconut palm (Cocos nucifera), are tapped for their sweet sap in tropical regions.
   • Extraction: Sap is collected from the trees’ stems or inflorescences and boiled into jaggery, a crude sugar. Palm sugar production is an ancient industry, especially prominent in India.
   • By-products: Toddy, a sweet sap from palms, is fermented to produce arrack, an alcoholic beverage.
5. Sorghum Syrup (Sorghum vulgare var. saccharatum)
   • Origin: Sorghum, native to tropical and subtropical regions, is widely cultivated for its juice, which is used to make syrup.
   • Processing: The stems are crushed, and the juice is evaporated into a nutritious syrup. In contrast to molasses, syrup retains all its original sugar content. Though sorghum juice is not a major source of sugar, the syrup it produces remains popular in the United States, particularly for cooking.

Starches and Starch Products

Starch, a complex carbohydrate, is a crucial reserve food source for green plants and holds significant importance in both the diet of animals and humans, as well as numerous industrial applications. It is stored in plant cells in the form of grains, which differ in size and shape depending on the source. The primary sources of commercial starch include cereal grains and underground tubers, although other plant organs like legumes and nuts may also contain appreciable amounts. Starch grains, as seen in various plant species, exhibit distinctive characteristics.

• Sources of Commercial Starch
  • Cornstarch: Derived from maize, cornstarch production involves soaking corn in water with sulfurous acid to prevent fermentation, followed by grinding, sieving, and separating. Most of the United States’ starch is made from corn, with over 400,000 tons produced annually. Cornstarch is used in both food products and industries, particularly in laundry starch and textile sizing.
  • Potato Starch: Europe is the leading producer of potato starch, with the U.S. producing around 30,000 tons annually. The production process includes washing, grating, sieving, and drying. Potato starch finds usage in textiles, glucose production, and industrial alcohol.
  • Wheat Starch: Wheat grains, one of the oldest commercial starch sources, pose challenges due to their gluten content. Wheat starch is primarily used in the textile industry.
  • Rice Starch: Extracted from broken rice grains, this starch is processed by softening with caustic soda, washing, and grinding. Its primary application is in laundry work and sizing.
  • Cassava Starch: Also known as tapioca, cassava starch is important in both food and industrial uses, particularly as a sizing material.
  • Arrowroot Starch: Sourced from various tropical plants, arrowroot starch is easily digestible and thus valuable as food for children and invalids. Its industrial use, however, is minimal.
  • Sago Starch: Extracted from the sago palm tree, this starch is processed by grinding the starchy pith and drying it into flour. Sago starch is predominantly used as a food product.
• Starch Products
  • Soluble Starch: Starch grains swell and burst in hot water, forming a thin solution known as soluble starch. This product is used widely in finishing textiles and paper production.
  • Dextrin: When starch is treated with heat, acid, or enzymes, it converts to dextrin, a tasteless, adhesive solid. Dextrin is used in postage stamp adhesives, crust formation on bread, and the steel industry, among other applications.
  • Glucose: Through further hydrolysis of starch with dilute acids, glucose is produced. Known in the U.S. as corn syrup, glucose is a valuable sugar used in food products such as candies and syrups. Over 1,000,000 pounds of glucose are produced annually in the U.S.
  • Industrial Alcohol: Starch from corn and potatoes is converted into sugar and fermented to yield industrial alcohol, primarily ethyl alcohol. It is a crucial solvent and base for manufacturing a wide range of products.
  • Nitrostarch: A chemical reaction between starch and nitric acid results in nitrostarch, used as a high explosive. During World War I, the U.S. developed cornstarch as a source of nitrostarch, producing large quantities for military purposes.

Cellulose Products

Cellulose, the most complex carbohydrate, is a primary structural component in the cell walls of plants. Its strength and versatility have made it a vital material for various industries, particularly those requiring robust plant fibers. Historically, natural plant fibers were utilized for textile and paper production. Over time, as agriculture advanced, the cultivation of these plants allowed for the production of longer, stronger, and more economical fibers. Today, advancements in cellulose chemistry have enabled the direct creation of synthetic fibers, marking a shift away from reliance solely on natural sources. These cellulose derivatives are integral to numerous aspects of daily life, highlighting the importance of cellulose in modern organic chemistry.

• Natural Plant Fibers and Industrial Uses
  • Plant fibers, consisting of cellulose, were initially used in their natural form for making textiles and paper. As industries evolved, plant cultivation techniques improved, producing better quality fibers. This evolution represents the early reliance on nature’s raw materials for fiber production.
  • As cultivation techniques advanced, plants with more desirable fiber characteristics were selectively grown, enhancing fiber length, strength, and affordability. These natural fibers continued to be a cornerstone of textile and paper industries.
• Synthetic Cellulose Fibers
  • The development of synthetic fibers marked a significant advancement in the industrial use of cellulose. By manipulating cellulose chemically, industries can now produce fibers directly from cellulose, reducing the dependence on natural sources. This development represents a key innovation in fiber production.
  • Synthetic fibers offer various advantages, including consistency in quality, flexibility in production, and adaptability to different industrial needs. This has expanded the applications of cellulose beyond what natural fibers alone could achieve.
• Cellulose Derivatives
  • Cellulose chemistry, a vital aspect of organic chemistry, has expanded into numerous fields, producing countless derivatives with practical applications. These cellulose-based products are highly valuable and found in many aspects of everyday life.
  • The transformation of cellulose into its derivatives demonstrates the versatility of this carbohydrate. Its ability to be modified for various uses, such as in synthetic fibers, is an essential aspect of modern manufacturing and technological development.

Artificial Fibers

Artificial fibers have a long history, beginning with numerous attempts to create silk-like materials, ultimately leading to the development of synthetic fibers in the late 19th century. The first synthetic fiber was created in 1880 by Count de Chardonnet, followed by the production of the first artificial silk shortly thereafter. Initially, these products were viewed skeptically, often considered inferior imitations of natural materials. However, by the early 20th century, artificial fibers had established themselves as unique materials with valuable properties, sparking the growth of an industry that continues to thrive. By 1935, the United States alone was producing over 250 million pounds of synthetic fibers annually, a sharp increase from the 800,000 pounds manufactured in 1911.

• Manufacturing Processes
  • The production of artificial fibers is achieved through at least four different processes, with approximately 85% of all synthetic fibers being produced via the viscose process. The Federal Trade Commission requires all synthetic fibers to be marketed under the name “rayon,” although various processes exist for creating these fibers.
• Raw Materials
  • The primary raw material for rayon is cellulose, which is purified from sources like cotton linters or wood pulp. This purified cellulose is dissolved using various solvents to form a liquid solution. The solution is then forced through small perforations, known as spinnerets, creating thin streams that coagulate into fine filaments. These filaments are caught on reels and twisted into threads suitable for spinning. These threads are subsequently washed, bleached, and dried, resulting in rayon fibers.
• Viscose Rayon
  • Viscose rayon is the original process for producing rayon and remains the most widely used method. It involves treating purified cellulose from wood pulp or cotton linters with caustic soda and carbon bisulfide, resulting in cellulose xanthate. This compound forms a foamy orange-yellow mass called viscose, which, after aging, is forced through spinnerets into a regenerating solution. In this solution, the xanthate groups are removed, and the cellulose filaments coagulate to form regenerated cellulose.
• Cellulose Acetate Rayon
  • Also known as “celanese,” cellulose acetate rayon is produced by treating cotton or wood pulp with acetic anhydride, acetic acid, and a small amount of sulfuric acid as a catalyst. Once dissolved, the material precipitates out as cellulose triacetate, which is then dissolved in acetone or other solvents. This solution, with the consistency of honey, is forced through spinnerets into a warm-air chamber, where the solvents evaporate, and the cellulose acetate filaments coagulate. Although acetate rayon is second in importance to viscose rayon, it is valued for its strength in the presence of moisture and reduced water absorption.
• Cuprammonium Rayon
  • In this process, cellulose is dissolved in ammoniacal copper hydroxide, producing a viscous solution. This solution is then forced through spinnerets into an acid bath containing caustic soda or sulfuric acid, where the filaments of regenerated cellulose coagulate. Cuprammonium rayon is another type of rayon produced from cellulose.
• Nitrocellulose Rayon
  • Known as Chardonnet silk or cellulose nitrate rayon, nitrocellulose rayon is one of the oldest synthetic fibers. Cotton linters are dissolved in a mixture of nitric and sulfuric acids to form pyroxylin, which is then dissolved in ether-alcohol or another solvent. The solution is forced through perforations to coagulate in the air, forming cellulose nitrate filaments. The nitro groups are later removed to reduce flammability. Though not as widely produced today, nitrocellulose rayon represents a significant early development in artificial fiber production.
• Properties of Rayon Fibers
  • Rayon fibers share some characteristics with natural fibers, such as the sheen of silk and an ability to take dye easily. However, they are not as strong or elastic as natural fibers, and they tend to absorb moisture, weakening when wet. They regain their strength when dried. Acetate rayon, on the other hand, absorbs less water, making it stronger in moist conditions, though it does not take dyes as easily as other types of rayon.
  • Rayon is versatile and can be used alone or in combination with natural silk or other fibers. When combined with other fibers, these mixtures may be dyed in two colors. The applications of rayon are wide-ranging, including shirts, underwear, hosiery, and braids. One common use of rayon is in men’s hosiery, where the outer layer is rayon, and the inner layer is cotton. The use of rayon continues to grow, owing to its adaptability and unique properties.

Other Cellulose Products

The solubility of cellulose in various solvents has paved the way for the development of numerous valuable and functional cellulose derivatives. These derivatives serve a wide range of applications across various industries, illustrating the versatility and significance of cellulose beyond its traditional roles.

• Cellulose Nitrate Products
  • When cellulose undergoes treatment with concentrated nitric acid in the presence of sulfuric acid, several forms of cellulose nitrate are produced. The nature of these nitrates varies based on the concentration of nitric acid, temperature, and reaction duration.
  • Higher cellulose nitrates are referred to as guncotton, or inaccurately, nitrocellulose, and are used extensively in the production of high explosives. For example, cordite combines guncotton with nitroglycerin, while smokeless powder is a mixture of guncotton and lower nitrates. Notably, guncotton is considered one of the safer explosives to handle, particularly in its wet form.
  • Conversely, pyroxylin, or collodion cotton, results from the partial nitration of cellulose and is produced under different conditions than guncotton. Pyroxylin holds significant industrial value, especially in photography, as it forms the base for film coatings. Additionally, pyroxylin’s solubility in various solvents leads to a range of useful products, including collodion, celluloid, plastics, artificial fabrics, and varnishes.
• Collodion and Its Applications
  • Collodion is a solution of pyroxylin in a mixture of ether and alcohol. When applied to a surface and allowed to dry, it forms a tough, impenetrable film, making it an effective protective covering for wounds. The popular wound dressing known as “New Skin” is an example of collodion’s application.
• Celluloid Production
  • Celluloid, a well-known derivative of cellulose, consists of pyroxylin dissolved in camphor. Invented in 1870 by John Hyatt, celluloid was created by mixing guncotton with camphor and applying heat and pressure. Today, celluloid can be produced by nitrating thin tissue paper or other forms of nearly pure cellulose, which is then mixed with camphor and dried. This material can be molded at 100°F and dyed to imitate various materials such as ivory, coral, and mosaics. Despite its versatility, celluloid is highly flammable.
• Artificial Fabrics from Cellulose Nitrate
  • Modern artificial fabrics are now produced using modified cellulose nitrate. In the past, oilcloth and linoleum were the primary materials derived from cellulose nitrate, requiring drying oils for their production. Today, modified cellulose nitrate combined with various solvents yields durable products used in applications such as automobile curtains, cushions, and leather substitutes for shoes and bookbinding.
• Advancements in the Varnish Industry
  • The varnish industry has been transformed through the use of cellulose nitrate. To meet the rapid demands of modern automobile production, fast-drying “lacquer paints,” such as “Duco,” were developed. This process involves bleaching and purifying cotton linters, converting them into cellulose nitrate, and mixing them with gums, resins, pigments, and solvents. The resulting varnish dries significantly faster than traditional varnishes, providing a durable finish suitable for both wood and metal surfaces.
• Cellulose Acetate Products
  • Cellulose acetate has also emerged as a critical industrial product, particularly in the film industry, where it serves as a safer substitute for cellulose nitrate due to its lower flammability. Although cellulose acetate films tend to be more brittle and costly, they are widely utilized in various applications, including automobile goggles, gas masks, automotive windows, index card coverings, artificial fabrics, and varnishes for airplane wings.
• Viscose Products
  • Viscose-derived products hold considerable importance, most notably cellophane, which is widely used for packaging and wrappings. Cellophane is created by forcing crude viscose through tiny slits, resulting in a thin, transparent film approximately 0.001 inches thick. This viscose film finds applications in numerous areas, including sausage casings and even replacing cotton in Welsbach mantles.
• Miscellaneous Cellulose Derivatives
  • Additional cellulose derivatives and products are noteworthy. Mercerized cotton, created by treating cotton fibers with caustic soda, results in a high luster and silky appearance. Parchment paper, produced by dipping paper in strong sulfuric acid, gains a hard, tough, translucent, waterproof, and greaseproof quality. Furthermore, cotton pulp paper can undergo vulcanization with a zinc chloride solution, rendering it hard and suitable for various mechanical uses, such as trunks and boxes.
  • Innovations have also enabled the conversion of cellulose in sawdust into industrial alcohol, acetic acid, and sugars through various chemical and bacterial processes. This ongoing research and development underscore the boundless potential for cellulose utilization across different sectors, highlighting its critical role in modern materials science.