Function And Application Of Konjac And Glucomannan Powder in The Biotechnolog...

Konjac, also known as devil's tongue, voodoo lily, snake palm, and elephant yam, is a perennial herbaceous plant belonging to the Amorphophallus genus in the Araceae family. It contains Konjac glucomannan powder(KGM), protein, starch, dietary fiber, various amino acids, and other substances. It has been used as a traditional food and medicinal resource in China. Due to its unique physicochemical properties, konjac has found extensive applications in numerous fields, including medicine, petroleum, chemical engineering, geology, automotive, printing and dyeing, construction materials, agriculture, environmental protection, aerospace, and aviation.

Classification of Bulk Glucomannan Powder

Konjac glucomannan powder is classified into six types: ordinary konjac powder, ordinary refined konjac powder, ordinary microfine konjac powder, purified konjac powder, purified refined konjac powder, and purified microfine konjac powder.

●Ordinary Konjac Powder: Granules with a particle size of ≤0.425mm (40 mesh) obtained from dried konjac (slices, strips, angles) through physical drying or rapid dehydration of fresh konjac followed by alcohol wet processing to remove starch and other impurities, with over 90% of particles in the specified size.

●Ordinary Refined Konjac Powder: Granules with a particle size between 0.125mm and 0.425mm (120 mesh - 40 mesh) obtained from dried konjac (slices, strips, angles) through physical drying or rapid dehydration of fresh konjac followed by alcohol wet processing to remove starch and other impurities, with over 90% of particles in the specified size.

●Ordinary Microfine Konjac Powder: Granules with a particle size of ≤0.125mm (120 mesh) obtained from dried konjac (slices, strips, angles) through physical drying or rapid dehydration of fresh konjac followed by alcohol wet processing to remove starch and other impurities, with over 90% of particles in the specified size.

●Purified Konjac Powder: Granules with a particle size of ≤0.425mm (40 mesh) and glucomannan content of over 70%, obtained from fresh Konjac through alcohol wet processing or from konjac refined powder through alcohol purification.

●Purified Refined Konjac Powder: Granules with a particle size between 0.125mm and 0.425mm (120 mesh - 40 mesh) and glucomannan content of over 70%, obtained from fresh konjac through alcohol wet processing or from konjac refined powder through alcohol purification.

●Purified Microfine Konjac Powder: Granules with a particle size of ≤0.125mm (120 mesh) and glucomannan content of over 70%, obtained from fresh konjac through alcohol wet processing or from konjac refined powder through alcohol purification.

Main Chemical Components of Konjac Corms
●Carbohydrates: Glucomannan is a major component unique to konjac corms, comprising a polysaccharide formed by d-glucose and d-mannose in a 1:1.6 molar ratio linked by β-1,4-glycosidic bonds. Its content ranges from approximately 44% to 64%. Other carbohydrates include starch and other polysaccharides.

●Protein and Amino Acids: Konjac corms contain 5%-10% crude protein and approximately 6.8%-8.0% total amino acids (including 7 essential amino acids).

●Minerals: Konjac is rich in various minerals, including high levels of K, Ca, Mg, Fe, Mn, Cu, and Co.

●Other Components: Alkaloid content is around 1%-2% and is toxic. Konjac also contains significant amounts of calcium oxalate crystals, requiring proper processing before consumption. Additionally, konjac processing can yield substances like ferulic acid, β-sitosterol, squalene, and xylose, as well as carotene, thiamine, riboflavin, and ascorbic acid.

Applications of Konjac

Konjac has a long history of use as a food ingredient, but the variety of products made in China is limited to konjac dried slices, konjac glucomannan powder, and konjac tofu. In recent years, with advancements in food processing technology and deeper research into the unique properties and functions of konjac, there has been a growing trend of developing processed foods using konjac as a main or auxiliary ingredient. The applications of konjac in the food industry have become increasingly diverse, including uses as a thickener, emulsifier, quality improver, and suspension agent in various products.

Leveraging the strong swelling, viscosity, and gelling properties of konjac glucomannan, products such as konjac tofu, konjac noodles, konjac vermicelli, konjac crystal cake, jams, salads, and fish roe substitutes can be produced.

The addition of konjac refined powder to food not only provides health benefits but also improves processing performance, extends the shelf life of products, and contributes to color, aroma, and flavor enhancement.

Adding 10%-20% konjac gel to pork sausages can produce low-fat sausages. KGM can be hydrolyzed to produce konjac beverages, and yeast fermentation can yield alcoholic beverages. Konjac gel added to seasonings can create konjac beef jerky and konjac fruit preserves.

●Applications of Konjac Refined Powder in Food

The application of konjac refined powder in food is primarily based on its water absorption, thickening, gelling, film-forming, and health-promoting properties.

In baking products like bread and cakes, adding konjac refined powder to flour improves dough stability, increases water absorption, enhances gluten strength and elasticity, and increases bread volume while preventing aging, resulting in a soft and delicate texture.

In noodles and vermicelli, konjac refined powder improves processing, prevents sticking during cutting and drying, maintains uniformity and smoothness in texture, and prevents over-cooking and sogginess.

Adding a certain proportion of konjac refined powder (e.g., 0.1%-0.5% for rice noodles, 0.5%-1% for sweet potato noodles, 0.1%-0.5% for bean noodles) to produce noodles results in a white color, good cooking resistance, non-cloudy broth, excellent texture, and long storage life.

In tofu, adding konjac refined powder improves elasticity, water retention, and texture, resulting in tofu that is tougher, less prone to breakage, smooth, and visually appealing.

In ice cream, konjac refined powder increases the viscosity of the liquid mixture, prevents coarse sugar crystal formation, and maintains a fine and smooth texture.

In beverages, konjac refined powder's significant thickening effect, especially under acidic conditions, makes it suitable for use in beverages with fruit pulp, enhancing the viscosity of juices and pulps and stabilizing fruit pieces.

In confections, using konjac refined powder in conjunction with gelatin to produce gummy candies yields soft, smooth, highly elastic, and unique-textured products with high water content, reducing production costs. Konjac refined powder has good gel strength, high elasticity, high transparency, no granules, and easy demolding, and its gelation is minimally affected by variations in precision, making it convenient and cost-effective to prepare.

In meat products, adding konjac refined powder to egg white sausages enhances meat binding and paste viscosity, resulting in well-structured products.

In simulated meat products, konjac refined powder can be used to develop simulated beef jerky with natural color, flavor, taste, and texture, and adding it to soy protein isolate enhances the spinnability of soy protein isolate.

In fruit and vegetable preservation, treating satsuma oranges with konjac glucomannan solution and methyl thiophanate extends storage life and maintains color and nutritional content. Konjac glucomannan's preservative effect is more significant than traditional methyl thiophanate preservation methods.

In health food products, konjac refined powder's alkaline gel combined with fruit juice produces fruit juice pellet beverages with certain health benefits.

Konjac refined powder and tea can be used to create konjac red tea and konjac flower tea formulas, processing techniques, and physicochemical qualities. These beverages have unique flavors and provide convenient nutritional and health benefits.

By inoculating selected mushroom strains into fermentation media containing konjac refined powder, a liquid fiber-rich konjac beverage can be produced. The liquid fiber content can reach over 0.5%, and the product is free of konjac odor and contains higher levels of protein, calcium, iron, zinc, and beneficial components of the mushroom body, offering certain health benefits.

Development Prospects of Konjac Products

Leveraging Konjac's food science properties and improving product taste and appearance through various means to enhance its nutritional value while maintaining its unique elasticity and texture will lead to the development of various types of Konjac food products.

Utilizing the various nutritional and health-promoting effects of KGM on the human body, a series of healthy food and functional food products are likely to gain popularity.

Due to the high medicinal value of konjac, further exploration is needed to isolate and purify certain medicinal components from konjac and develop new drugs.

Konjac glucomannan powder can be used as a raw material to research and develop daily-use products such as face masks, skin toners, soaps, and cosmetics.

Leveraging the synergistic effects of konjac, konjac gel, and other colloids, green and environmentally friendly plant gels can be developed for use as preservatives, adhesives, flocculants, suspension agents, and stabilizers in food, printing and dyeing, papermaking, and pharmaceutical industries.

References:

Ma, J., & Qi, Y. (Year). Function and Application of Konjac and Konjac Powder.

Zhao, Z., Lei, M., & Lu, X. (Year). Current Processing Status and Development Prospects of Konjac Products.

Wu, Q., Sun, Y., Huang, X., & Shen, G. (Year). Research and Application Status of Konjac Refined Powder.