Comprehensive utilization of orange peel

1 Introduction The cultivation of oranges in more than 80 countries around the world ranks first among all fruits, reaching more than 300 million tons. From 1999 to 2000, the total volume of citrus production in the world was about 90,868,800 tons. China is one of the major citrus producers in the world. In 1997, the citrus planting area in China was 19.62 million mu, and the output reached 10.102 million tons. In 1999, it was 10.5871 million tons. The planting area ranked the first in the world, and the output ranked third in the world. The number of orange peels of fresh oranges and processed leftovers accounts for about 20% of citrus output. In addition to water, cellulose, and lignin, it also contains rich essential oils, pigments, pectin, and orange peel. This kind of renewable biological resources has been abandoned in most of China's unutilized areas, resulting in great waste and environmental pollution problems. If this resource is used comprehensively, it will turn waste into treasure and greatly increase the economic benefits of the citrus industry. 2 Comprehensive Utilization of Citrus Peel 2.1 Extraction of orange peel orange peel There are many ways to use it, the most important of which is to extract orange peel oil, which is also the most important natural source of alkenes. Orange peel oil is extracted by cold pressing, distillation, extraction, etc. The most commonly used method is steam distillation. Principle of Steam Distillation: Orange oil is a volatile aromatic oil that is present in the skin cells. When steam distillation is used, the oil-containing cells burst due to increased temperature and water intrusion. The oil is distilled out with steam and condensed. And oil and water separation, so as to get orange oil. Fresh orange peel oil yield is 1% to 2.4%, dry skin is 3% to 4%. The aroma of orange oil extracted by cold pressing method is closer to fresh fruit aroma. Regardless of the method used, the extracted fruit residue can be used for other purposes, for example, as feed, non-staple food, or to extract pectin, hesperidin. Orange oil is one of the important bulk commodities in aromatic oils. It has a wide range of uses and is widely used as a food, daily chemicals, flavors and fragrances cosmetics industry, and some of them are used medicinally. 2.2 Extraction of orange peel pigment As a food additive, the pigment is widely used in food production. In the past decade, the development of natural food coloring instead of synthetic pigments has become the development trend of the food coloring industry. The natural colorants extracted from fruits and vegetables that people have eaten for a long time are safe to eat, so countries around the world are making great efforts to develop and use natural colorants. Extracting pigments from orange peels can not only change waste into treasures and increase the added value of citrus, but also can add substances with good health-care functions such as Î²-carotene and carotenoids, which are the main components of pigments, to foods. The nutritional value of food. Extraction process: Dry orange peel â†’ Solvent extraction â†’ Filtration â†’ Filtrate â†’ Refinement â†’ Concentration â†’ Vacuum drying â†’ Orange peel yellow filter â†’ Filter residue â†’ Concentrate â†’ Solvent recovery The extract is 95% (volume fraction, the same below) of ethanol. When leaching, the ratio of dry skin and extracts is 1:4 by mass. Different concentrations of ethanol soak can also be used. There are many kinds of oranges, skin color from red to yellow, different shades, so different orange peel pigments have different properties. Red orange peel pigment is a carotenoid mixture mainly composed of T-carotene, which is insoluble in water and easily soluble in oil; and yellow orange peel pigment is easily soluble in water, and may be methoxyflavonoids and carotene. A mixture of lutein and the like. 2.3 Extraction of pectin Pectin is a polysaccharide polymer compound that is ubiquitous in plants and acts as a softening and viscose to tissues. Dried orange peel contains up to 20% pectin. As far as the extraction method is concerned, there are mainly two kinds of alcohol precipitation method and salt precipitation method, and the alcohol precipitation method has better color. Ethanol precipitation is commonly used for ethanol precipitation, and isopropyl alcohol is also used. One of the extraction processes is as follows: 0.5% HClâ†’Insulation Extraction 0.5% NaOHâ†’adjust pH value isopropanolâ†’alcohol analysis 70% Isopropanol â†’ Alcohol wash dried orange peel â†’ Insulation extraction â†’ Filtration â†’ Filtrate â†’ Decolorization â†’ Adjust pH â†’ Alcohol analysis â†’ Filtration â†’ Filtrate â†’ Alcohol wash â†’ Vacuum drying â†’ Product filtration â†’ Filter residue â†’ Activated carbon or orange peel The extraction yield of glucoside pectin differs depending on the process, and the highest extraction yield can reach 21.6% (dry skin). Pectin is the main component of dietary fiber in the body's seven nutrients. It has good anti-diarrhea, anti-cancer, anti-diabetic and weight-loss effects, and pectin has good gel and emulsion stability. It is widely used in the food industry. It is also an indispensable accessory for the pharmaceutical and cosmetic industries. Pectin as a food additive, with its excellent taste and low sugar, low calorie performance, has a good market in the domestic and foreign markets, the annual growth rate of about 4% to 5%. Extracting pectin from agricultural and sideline products has great economic and social benefits. 2.4 Extract hesperidin orange peel rich in hesperidin, content of about 3%. The traditional methods for extracting hesperidin from orange peel are solvent extraction and lye soaking. Raw materials are generally directly used orange peel, can also be used after the extraction of pectin slag. A better solvent than the traditional process - alkali method is as follows: 95% Ethanol â†’ Insulation Leaching Saturated Calcium Hydroxide Solution â†’ Filtrate Dilute Hydrochloric Acid â†’ Adjust pH 95% Ethanol â†’ Alcohol wash dried orange peel â†’ Insulation extraction â†’ Cooling filtration â†’ Filtrate â†’ Static filtration â†’ Filtrate â†’ Adjust pH â†’ Let stand â†’ Centrifuge â†’ Precipitation â†’ Alcohol wash â†’ Wash â†’ Dry â†’ Product Hesperidin is a yellow Alkanone glycosides, pure white needle crystals or light yellow powder, insoluble in water, slightly bitter, melting point 258 ~ 262 Â°C. It is a component of vitamin P and has the functions of maintaining the normal osmotic pressure of blood vessels, reducing the brittleness of blood vessels, and shortening the bleeding time. It is an effective therapeutic and preventive agent for vascular diseases caused by hypertension and arteriosclerosis. In Europe, it is also used to make oral medications for the treatment of chronic vascular diseases. According to Xinhuanet.com, due to the ability of hesperidin to dilate capillaries, Shiseido Corporation of Japan is using hesperidin to develop lipsticks with a high degree of shine. In addition, hesperidin obtained from hesperidin can be made into medicinal cosmetics, nutritional cosmetics and medicines for treating skin spots such as dark spots and freckles. 2.5 Preparation of orange peel powder: Process flow: Clear waterâ†’soaked dried orange peelâ†’soakingâ†’brine boilingâ†’rinsingâ†’dryingâ†’pulverizationâ†’sievingâ†’solvent treatmentâ†’filteringâ†’filtered residue dryingâ†’pulverizationâ†’sievingâ†’finished product filtrationâ†’solvent recovery orange peel powder is orange peel comprehensive utilization One of the products is a good incremental filler that can be used as a binder for laminates, and can also be widely used in nutrition jams, ice cream, ice cream, yogurt, pies and other foods to improve the structure of food products Improving the flavor and texture of foods; adding to frozen drinks can improve the gelling ability and shape retention of such foods, making them less soluble and prolonging their preservation period. 2.6 Preparation of natural beverage clouding agents In order to make fruit juice beverages, especially fruit juice beverages with low fruit juice content, have a good appearance and improve the stability of the storage period, methods for adding clouding agents are generally used, and the use of synthetic clouding agents is strictly limited. Therefore, it is necessary to develop natural beverage turbidity agents. Orange peel is an ideal raw material for preparing natural clouding agents. Starting from the current situation in China, on the one hand, the comprehensive utilization of citrus peel resources is enhanced and the economic benefits of citrus are increased. On the other hand, citrus juice provides a A good natural clouding agent to replace the use of synthetic clouding agents. Preparation of clouding agent process flow: Dilute Hydrochloric Acid â†’ Boiling Water Cooking Pectinase â†’ Enzymolysis Fresh Orange Peel â†’ Boiling Water Cooking â†’ Fresh Water Rinse â†’ Leaching â†’ Grinding â†’ Adjusting pH â†’ Enzymolysis â†’ Press Filtration â†’ Filtrate â†’ Inactivation Enzyme â†’ Product Refinement Orange Peel: Water Mixing in a ratio of 1:2 or 1:3, ground into an orange peel slurry or further ground into a fine-grained orange peel slurry with a colloid mill, adjust the acidity to pH 5.0, and the enzymatic hydrolysis temperature is 50Â°C. The inactivation time was 5 min and the temperature was 95Â°C. 2.7 Extraction of antioxidants Edible antioxidants are one of the most important food additives. They can slow down the rancidity of oils and fat-rich foods and extend the shelf life of foods. Due to the adverse effects of synthetic antioxidants on human health, the development of natural antioxidants since the 1970s has become a research hot spot for food scientists. The following is the extraction process of one antioxidant from orange peel: Dried Orange Peeling â†’ Crushing â†’ Diffusing Organic Solvent â†’ Filtration â†’ Filtrate â†’ Concentration under reduced pressure â†’ The product extraction solvent can be ethyl acetate, anhydrous ethanol and ether. The leaching conditions are: room temperature, sealed and stirred, and diffused for 10 h. The above leachate was filtered, and the filtrate was concentrated under a reduced pressure of 70[deg.] C. until no filtrate was distilled off for another 30 min to obtain extracts of different solvents. The extracts had excellent anti-oxidation abilities to oils and fats. 2.8 Preparation of natural anti-mold agents Modern scientific research has proven that some components of orange peel have the effect of inhibiting bacteria, killing cockroaches and flies. Japanese agricultural experts add volatile oil extracted from the orange peel to the feed to extend the shelf life of the feed. Mold is the main pollutant in feed. In order to control mildew in feed, the use of natural anti-mold agents can overcome the disadvantages of large toxic side effects and long residual period of chemical synthesis of anti-mold agents. The anti-mould agent preparation process is as follows: Organic solventâ†’Insulation extraction solvent recoveryâ†’Pressure reduction distillationâ†’Oily extract orange peel powderâ†’Insulation extractionâ†’Cooling filtrationâ†’Platesâ†’Distillation under reduced pressureâ†’Oily extractsâ†’Preparation of emulsionsâ†’Products Preparation by dry glue method The emulsion, its orange peel extract: distilled water: gum arabic, was mixed in a ratio of 4:3:1, quickly ground into colostrum, and finally diluted to a concentration of 60%, and was bottled. Among them, the organic solvent with diethyl ether has good bactericidal effect. After research, the product has inhibitory effects on Penicillium oxalicum, Aspergillus fumigatus, Fusarium falciparum, Aspergillus flavus, Aspergillus versicolor. 2.9 Preparation of citric acid from citric acid The fruit residue after the extraction of pectin or orange peel oil can be used. The process is as follows: Calcium carbonate â†’ precipitated sulfuric acid â†’ acid hydrolysis of citrus residue â†’ pressing â†’ juice â†’ concentration â†’ molasses citrus residue â†’ pressing â†’ solids â†’ drying â†’ dried tangerine molasses + dried tangerine peel â†’ mixed â†’ killed seedling â†’ inoculation â†’ fermentation â†’ sedimentation â†’ filtration â†’ filter residue â†’ Acidolysisâ†’concentrationâ†’crystalsâ†’washingâ†’dryingâ†’dryingâ†’Products The above process can produce 215 g of citric acid per 100 kg of citrus waste. Citric acid is a colorless, translucent crystalline or white powder with an acid odor of fruit. Citric acid is used as a food additive and is widely used in food, beverage manufacturing and grease processing industries as a sour agent, softener, preservative and antioxidant. 2.10 Preparation of Activated Carbon for Preparation of Activated Carbon After the extraction of pectin residue, the process is as follows: Orange peel residue â†’ drying â†’ carbonization â†’ crushing â†’ cooking â†’ washing â†’ centrifugation â†’ drying â†’ crushing â†’ sifting â†’ carbonization temperature of activated carbon product is 400Â°C, 5% hydrochloric acid is added during the cooking process, and the adsorption amount of the obtained product is 0.1494 g. Methyl blue / 1g. Activated carbon is widely used in the food industry, chemical industry, metallurgical industry, and environmental protection industry, and is one of the most important products of forestry. 3 Conclusion There are many uses for orange peel. The above only briefly describes several aspects of domestic research. As a major citrus power in China, for a long time, most of the orange peels have not been well utilized. With the development of the economy and the improvement of peopleâ€™s living standards, humanity has increasingly demanded strict food functions. Utilizing China's abundant natural resources to process a series of food additives is the direction of development. This not only promotes economic development, but also promotes the improvement of agricultural efficiency, thereby getting rid of the low efficiency and low output value of China's agriculture and forestry.