Nowadays, even buying eggs seems to be complicated. In addition to the common firewood eggs on the market, special eggs such as low-cholesterol eggs, high-iodine eggs, and calcium-added eggs are also everywhere. Recently, the rumors about "fake eggs" have aroused people's attention. This year's "rubber eggs" can achieve "the egg yolk falls to the ground and can bouncing 20 cm high." However, the reporter learned after the interview that the "rubber egg" is not a fake egg, but it may be because the chicken feed is used as a cockroach, which contains too much gossypol as a source of protein. It is a substandard product, although it cannot be proved that the content can be To the point of being harmful to the human body, but as a risk that can be circumvented, there is no need to entangle the true and false eggs and throw them away. And what kind of egg has the highest nutritional value, how to pick fresh eggs? "Artificial Eggs" is theoretically feasible, but the cost of fraud is high. "We have done experiments on synthetic raw materials for chemical raw materials a long time ago. In theory, artificial eggs are possible." Dong Jinshi, the executive vice president and secretary general of the International Food Packaging Association, said that "artificial eggs can be used in chemical industry." It is made of materials and food additives. The eggshell is made of calcium carbonate, paraffin and gypsum powder. The egg white and egg yolk are made with sodium alginate and alum, gelatin and pigment. The main component of artificial egg is sodium alginate. After gelatinization, there will be certain elasticity and viscosity. The market price of sodium alginate is about 4,000 yuan/ton. The raw material cost of each artificial egg is about 1 cent, but the cost of real eggs is very cheap. From an economic point of view, there is no need for fraud." Dong Jinshi said that so far, no factory that really made "artificial eggs" has been found, and sodium alginate is difficult to solidify under heating conditions. "The theory is feasible, but for the cost-effective egg fraud, it requires a certain amount of technology, profit margins are limited, and the danger is also great." Fan Zhihong, associate professor of the Department of Nutrition and Food Safety, College of Food Science, China Agricultural University, said. "It is more difficult to prove that it is more difficult than falsification. If there is such a "dedication" of counterfeiters, not only "falsing" the eggshell, but also making the protein and egg yolk so vivid, and achieving the overall cost lower than the real egg, it needs to be very High technology, "fake spirit" is too "dedication"," said nutritionist Gu Zhongyi. "Fake eggs" are all under the chicken, just unqualified eggs In fact, the "producer" of the egg, the feeding environment of the chicken, the health of the chicken itself, the composition of the feed and the variety are the reasons for the color, hardness, egg yolk and protein color of the egg. “The hen is a reactor that converts the feed into meat and eggs. If the reactor is not or the raw materials are unqualified, it may produce unqualified products. It is not unexpected that the real eggs under the hens are unqualified.†A member of the Scientific Squirrel Society, Dr. Yun, a doctor of food engineering at Purdue University, stressed on Weibo that although many people are accustomed to not believing that “the relevant departments†say that these eggs are not fake eggs, they are just unqualified eggs. But so far, the conclusion that the tested "fake eggs" are chickens is credible. Because it is easy to judge by protein that its composition is about 12% aqueous solution of protein, or sodium alginate. Focus on "rubber eggs" The high content of gossypol in the feed is the main cause of What is the abnormality of the egg yolk of the rubber egg? “The most common cause is the high content of gossypol in the feed. It comes from chicken feed cottonseed cake, which is the residue after cottonseed oil extraction. It is an oily feed, and puffed soybean, bean cake, peanut meal, sesame meal, sunflower. Seed meal, zein and so on are rich in protein and are often used as a source of protein in chicken feed. Cottonseed contains a pigment called "gossypol", which is combined with lysine in proteins to prevent it. It is absorbed and utilized. In addition, gossypol also inhibits protease activity in the gastrointestinal tract, which affects the growth of chickens and affects the yield and quality of laying eggs." Yun said. If it is only a low content of gossypol, it has no adverse effect on the growth of chickens, and its low price and protein content can be very attractive to chicken breeders. “If you can control the total amount of gossypol, the chicken farmers will want to add cottonseed cake as much as possible. The gossypol content in cottonseed cake is closely related to the cotton variety and processing technology. The low per kilogram may only contain one or two hundred milligrams. The high can reach more than 5,000 mg. If the content of gossypol in the cottonseed cake is not accurate, there may be the consequences of "add too much"." Free-range chicken, firewood eggs are also likely to recruit The cloud has no intention to say that there is a large amount of data that found that the high content of gossypol will lead to rubber eggs. In addition, cottonseed cakes and many plants also contain a class of substances called "cyclopropene-like", which can also lead to the appearance of rubber eggs. Even a free-range chicken, even if it is a firewood egg, may be tricked. “In the United States, there is a kind of weed called “castor†that often thrives in corn fields. Under the mechanized planting and harvesting methods in the United States, their seeds are easily mixed into corn. Corn. In addition to this weed, its close relatives can have similar consequences." Gu Zhongyi also confirmed that “the high content of gossypol may cause the egg yolk to harden†has been documented. "Recently, some media have reported that some edible oils are reported to be "toxic oils" made from cotton oil and soybean oil. Among them, free gossypol exceeding the standard is toxic, gossypol can be used for birth control, and eating raw cotton oil can cause infertility." But it may also be because the eggshell is caused by tiny cracks that are not noticed by the naked eye. Fan Zhihong said, "I have seen the eggshell of organic eggs has a slight crack, not broken, so that the inside of the eggshell is no longer a relatively closed space. If there is water leaking out, it will harden after being put out in the refrigerator for a long time, or Put the eggs into the bowl and watch them every few days. The egg whites and egg yolks are hardened." It may be caused by improper transportation, etc., resulting in "rubber eggs". "If only a few eggs, egg yolks are hardened in a batch of eggs, At most, the transportation is improperly preserved; if one of the eggs is a rubber egg, it is a catastrophe caused by gossypol." [Reminder] "Although even if the rubber egg is caused by gossypol, the content may not reach harmful levels, but even if the risk is small, it can be completely evaded. Therefore, it is good to be discreet and throw it away." The cloud has no heart to say. Experts remind Freshness is the main criterion for judging the value of nutrition. ◠Fan Zhihong, Associate Professor, Department of Nutrition and Food Safety, College of Food Science, China Agricultural University Judging the nutritional value of an egg, its shape, size, color, etc. does not hinder it as a normal egg, the most important criterion is its freshness, but in fact the fresh egg is relatively heavy, because in the egg The water does not evaporate and the air chamber is relatively small. Slightly shake it, there is no movement for fresh eggs. In another detail, the color of the eggshell has nothing to do with the nutrition of the egg, but the darker the eggshell is, the stronger it is. The smaller the air chamber is, the less easily the water is evaporated, the thin eggshell is easy to break, and the relative freshness is poor. . Eggs should generally be stored in the freezer of the refrigerator at zero degrees. Some people like to eat frozen eggs. They like this taste and have no problem. When picking eggs, it is recommended to buy small-packed eggs, try to buy the most recent packaging date, instead of paying attention to advertising gimmicks, do not eat cracked eggs. If the egg is not fresh, the protein will be partially decomposed. If it is egg tart, it will not be easy to coagulate. The taste is older. If the cake is made, the foam is not delicate enough. Therefore, considering the dual factors of nutrition and taste, buying fresh eggs is the most important thing. of. Taking the "appearance" to take the eggs is basically applicable to The evaluation of whether an egg is a "good egg" can be "appearing". "Indices that affect egg quality are: egg weight, egg specific gravity, eggshell thickness, eggshell strength, eggshell color, protein height, egg yolk membrane strength, egg yolk color, chemical composition, blood spots and spots, taste and odor. Gu Zhongyi explained, that is, if the egg is too small or too large, it grows into a cone or a sphere, or the eggshell is particularly hard, or there is no eggshell, or blood spots, or egg yolk is particularly hard, or scattered. Yellow, or eggs with the same water, or eggs that have produced ammonia and astringent taste, can be judged as "unqualified eggs." The special additive in chicken feed has a kind of coloring agent, which can make the eggshell and egg yolk color better, but the nutritional value is not much different. Our reporter Wang Yuanzheng photo Affecting egg quality factors Feed can affect egg quality and egg yolk color There are many factors that affect the quality of eggs. Even if the age of the chicken becomes larger, the color of the eggs will be different. “Man-made control of feeding environment, feed and chicken breeds, and the selection of conditions that meet the needs of human sensory needs will affect the quality of eggs. For example, feed, chicken feed is divided into energy feed, protein feed, mineral feed, special additives and green feed additives. When the feed is deficient in calcium, the chicken is prone to produce soft-shelled eggs or eggs without eggshells. If the calcium content is high, the eggshells will be hard and the egg yolk color will be different. The lutein in the feed has coloration on the yolk. Significantly, the content of lutein in corn is high. After eating the chicken, the egg yolk is darker in color. If you eat wheat feed, the content of lutein is low. When it is replaced by corn, the yolk will be lightened. The corn is mixed with corn oil and soybean oil. The same high energy feed will also affect the weight of the eggs." Gu Zhongyi said. Cottonseed feed also affects the color of the yolk. "The feed of gossypol is too high, the tannic acid content is too high, it will also lead to yolk variegated, of course, calcium deficiency, drugs, insecticides, storage time at high temperatures, etc., may also lead to yolk variegated. In the grain, some varieties of sorghum contain a large amount of tannins. Feeding chickens with such sorghum is also prone to yolk variegated. In the cottonseed cake or weeds, "cyclopropene-acid", in addition to causing rubber eggs and variegated egg yolks It may also cause redness of the protein." Yun said without heart. Although sensory quality has little to do with nutritional value, consumers still believe that the color of the egg can judge the quality and flavor of the product. For example, the golden or orange-red egg yolk is used as an important indicator of egg quality. “Special additives in chicken feed are divided into two categories, one is phytase, because chicken feed contains a lot of phytic acid, which will affect the absorption of other nutrients by chickens. Phytase can promote the absorption of nutrients; The class is a coloring agent that makes the eggshell and egg yolk color better. For example, the eggs of Sudan red are added in the past few years, or the color of the egg yolk is added to change the color of the egg yolk. Even adding some red pepper powder can make the egg yolk color deeper. "Gu Zhongyi said. However, in addition to the excessive addition of additives, there is not much difference in nutritional value. Chicken disease will also affect egg safety "Respiratory diseases can make the color of brown eggshells lighter and the intensity is abnormal. Chicken parasites can easily cause blood spots in eggs." Gu Zhongyi said. If the chicken gets sick, it will affect the quality and safety of the eggs. When the eggs are selected, the eggs that are not like eggs should be discarded if they have blood spots, cracks, soft or too thin egg shells, too hard, and abnormal color. According to foreign reports, a food company in Minnesota recently recalled more than 1 million boiled eggs sold in 34 states, as some of them were detected to be infected with Listeria. Listeria is serious or even fatal to the old and weak, and even healthy adults, after infection, will have short-term symptoms such as headache, runny nose, abdominal pain and high fever. Eggs suffering from microbial infections pose a food safety risk. “Generally, yellow eggs are contaminated by bacteria and cannot be eaten.†Safety incidents such as environmental pollution are difficult to monitor. For example, if the pollutants in the water exceed the standard, the farming industry will drink the contaminated water to the chickens, or pollute the environment and feed. The dioxin pollution causes a large amount of food such as eggs, milk and milk powder. Exceeded the standard. Even the use of contaminated barrels of industrial waste oil to load animal feed is something that regulators need to pay close attention to. A granite cutting rope saw Jiangyin Baoneng Precision New Material Co.,LTD , https://www.baonengwire.com
