abstract
About the cause of crystallization
Influencing factors of crystallization
Crystallization characteristics
abstract
About the cause of crystallization
Influencing factors of crystallization
Crystallization characteristics
Expand and edit this paragraph overview.
Honey crystallization is a common problem in the process of eating honey. With the extension of time and the change of temperature, especially in winter, honey often changes from liquid to crystalline, and its color changes from dark to light. Most honey seeds are milky white or white, delicate or rough translucent crystals after crystallization. This change in honey often causes some people to misunderstand that it is caused by honey mixed with sugar. In fact, this is the natural physical change of honey, not the result of mixing sugar. Honey crystallization is a physical change phenomenon, and its chemical composition and nutritional value have not changed like water freezing, which will not affect the quality of honey. The crystallized crystal is glucose, not honey mixed with sugar. In fact, honey mixed with white sugar is not easy to crystallize, and honey that is easy to crystallize is pure honey. Therefore, China's honey quality standards stipulate that the normal state of honey is "transparent and viscous liquid or crystal". Honey crystallization is that glucose forms particles around the crystal nucleus, and the particles are wrapped with a film of fructose, sucrose or dextrin, which gradually coalesces and expands, so that part or all of the honey in the whole container forms a loose solid state, that is, honey crystallization. Therefore, honey crystallization is a normal phenomenon, which has no influence on its nutritional components and application value, and does not affect eating. The natural properties of honey crystals are of great significance for sensory identification of authenticity and naturalness, but if we want to identify different varieties of honey, we need to rely on its unique fragrance to make a judgment. The fragrance of honey includes smell and taste. The smell of honey is the smell of different kinds of honey, which is consistent with the smell of flowers of this honey source plant. This smell comes from the aromatic gland secretion of flowers, and its main components include alcohols, alcohol oxides, esters, aldehydes, ketones and other compounds and amino acids. The richness and complexity of these substances lead to the qualitative differences of honey smells of different flower species, which are different from each other and have their own characteristics, and become irreplaceable important sensory indicators to distinguish honey varieties. The national standard "Honey" divides the smell of honey into faint fragrance, slight fragrance, faint fragrance and strong fragrance. This only reflects the strength of honey smell, ignoring the difference of honey smell quality. The same fragrance, the elegant fragrance of Chinese milk vetch honey is different from the grass fragrance of Chinese milk vetch honey; The fragrance is also rich, and the unique mint fragrance in linden honey is different from the refreshing fragrance in citrus honey; The same medicinal fragrance, the strangeness of wild agastaches, the peace of Astragalus and the freshness of Lycium barbarum. What distinguishes this kind of honey from that kind of honey lies in what kind of fragrance this kind of honey should have and what kind of fragrance that kind of honey should have. The strength of honey fragrance only plays an auxiliary role in distinguishing the single degree of honey varieties and the quality difference caused by production methods. For example, honey, which should be rich in fragrance, is actually not rich. It may be that the purity of this honey is not enough, it may be artificially processed, or it may be mixed with honey. Generally speaking, the smell of honey is consistent with the fragrance that this honey source emits into the air when it blooms, that is, the fragrance type and shade degree of honey are consistent with the fragrance type and shade degree that this honey source emits into the air when it blooms. But there are some special cases of asynchronization. For example, when Robinia pseudoacacia blooms, the fragrance all over the mountains is rich and charming, while the nectar of Robinia pseudoacacia is only faint and straight into the heart and spleen; On the contrary, the smell of buckwheat honey is much weirder and stronger than that of buckwheat flowers, which is related to the position of aromatic glands and the secretion time of flowers. The opening of the aromatic gland of Sophora japonica is far from the opening of nectar, and the secretion of the aromatic gland ends before the nectar flows out, so the fragrance of Sophora japonica honey is far less rich than that of Sophora japonica, and the fragrance type is also different. The opening of fragrant gland of buckwheat is very close to the opening of nectar, and the secretion of fragrant gland is often covered by nectar, so the smell of buckwheat honey is much bigger than that of flowers. The taste of honey is the taste feeling of honey in the mouth. Just like the smell of honey, different kinds of honey have different tastes and are in harmony with the fragrance of flowers. Although they are all sweet, each has its own sweetness. Litchi honey is sweet with litchi flower fragrance, jujube honey is sweet with jujube flower fragrance, and gallnut honey is rich in gallnut anther sweetness, which is completely different and easy to distinguish. But as an exception, there are some kinds of honey whose taste and smell are different, such as sweet pepper honey and goldenrod honey, which have a strange smell, almost smelly, but more palatable to eat. We can often see some brands of honey, all kinds of names and varieties in the market, but their smells and tastes are the same, or they are not honey at all. Some are Gui Li honey, which is a multi-angle play of honey, or it is not honey at all. Although some tastes and smells are different, the actual tastes and smells are not those indicated on the label. This is another form of impersonation or forgery. As long as consumers seriously understand these basic characteristics of honey, they will not be unable to buy real honey!
Edit this paragraph about crystallization.
Crystallization reason
Why does honey crystallize? First of all, we must understand the basic ingredients of honey. Honey contains a variety of nutrients, and sugar accounts for about 80% of the total substances, among which fructose and glucose supersaturated solution account for 85-95% of the total sugar, and sucrose accounts for about 5%. Because glucose is easy to crystallize, the separated honey will gradually crystallize if it is left at low temperature (0- 14 degrees) for a period of time, so the crystallization of honey is actually caused by glucose in honey, which mainly depends on the ratio between glucose and fructose (not easy to crystallize), that is, the percentage of glucose in reducing sugar. Generally speaking, when the contents of glucose and fructose are equal, the crystallization is slow; When the ratio is 1: 2, crystallization generally does not occur; When the ratio is 1: 0.9, that is, when the glucose content is higher than the fructose content, crystallization will occur soon when the temperature is appropriate. For example, the ratio of glucose to fructose in Sophora japonica honey is about 2: 3, so it is not easy to crystallize; Rapeseed honey is about 18: 17, but the crystallization speed is very fast.
Influencing factors of crystallization
The speed of honey crystallization is related to its glucose crystal nucleus, temperature, moisture and honey source. The crystal nucleus of glucose in honey is small, and there are pollen grains in honey. Under certain conditions, the glucose in honey grows and crystallizes around these tiny crystal nuclei. The more crystal nuclei contained in honey, the faster the crystallization rate. The crystallization speed of honey is also affected by temperature, and 13- 14℃ is the easiest to crystallize. If it is lower than this temperature, honey crystallization will be delayed because of its viscosity increase. If it is higher than this temperature, the solubility of sugar will increase, thus reducing the supersaturation of solution and slowing down crystallization. In addition, all crystallized honey is generally immature honey with low water content and high water content, which will slow down the crystallization speed or make the crystallization incomplete due to the decrease of supersaturation of the solution. Different kinds of honey have different crystallization, such as milk vetch honey, locust honey, jujube honey, dangshen honey, etc., which are not easy to crystallize; Rapeseed honey, wild croton honey and cotton honey are easy to crystallize. False honey does not crystallize. Honey is a supersaturated solution of sugar, and most of it will crystallize out during storage, resulting in stratification or solids, which will affect the sensory characteristics of honey and the shelf performance of goods. Merchants do what consumers like and process honey (crystal nucleus crushing process). Usually, a large number of honey crystal nuclei are filtered by a screen with a mesh of more than 200 meshes, and heated at a temperature of more than 77 degrees to melt and remove them, so that they do not crystallize or crystallize less. There are also bad manufacturers who directly mix malt syrup into honey, so that honey will never crystallize! In addition, China's beekeeping farms mainly stay in the price range of producing immature honey (low-grade honey, honey with water content above 23% or below 40 degrees). Although this low-grade immature honey has low price and high yield, manufacturers are willing to buy this low-priced honey, but it ferments quickly and can only concentrate water through mechanical processing. At present, the dehydration processing of honey is mainly based on heating evaporation process, and heating has a great influence on the original nutrition and taste of honey. Include removing crystal nucleus, and is not easy to crystallize. This kind of honey has a bad taste, mushy taste, high consistency, no fragrance, almost the same color and deep color, and there is little difference in the flavor of honey varieties from various flower sources. However, the color, fragrance and taste of natural and mature honey are completely different from those of single nectar from various flower sources, and the unique flavor will not be the same. Moreover, most kinds of honey will crystallize in winter, and its nutritional value is incomparable to that of processed concentrated honey. This is the difference between naturally mature honey and processed concentrated honey. Honey needs crystallization, and crystallization is an inherent property of honey. This extremely simple and common phenomenon should be presented to consumers, but in the market, it is a completely different scene: most honey has not crystallized (occasionally crystallized, abnormal), and a large number of amorphous "honey" has played an objective suggestion role, so that many consumers can't tell the difference between true and false, which is deeply confusing.
Crystallization characteristics
When honey is first taken out of the hive, it is usually in a viscous liquid state. But with the passage of time, honey will gradually become turbid, solidified or hardened, from liquid to semi-liquid until solid, and the color will also change from dark to light. The crystallization characteristics of honey have the following rules and characteristics: 1. Comprehensiveness means that all honey will crystallize. The normative appendix (Appendix A) of Chinese national standard Honey (GB 18796-2005) describes the crystallization of honey as crystallization, easy crystallization, easy crystallization and difficult crystallization respectively, which objectively reflects the fact that honey is fully crystallized. Among them, the key is the accurate understanding of "not easy to crystallize". We think that what we mean here is the slow speed and degree of honey crystallization, not "not crystallization". This is also the result observed by the author in the long-term beekeeping production practice. So far, no completely amorphous honey has been found. The comprehensiveness of honey crystallization is also manifested in that no matter what kind of honey, its crystallization is comprehensive and relatively uniform. The crystallization of "finally settling to the bottom of the container" is abnormal, and the local crystallization of honey only exists in immature honey, artificially concentrated honey and honey during crystallization or melting. 2. Crystallization of honey is that all kinds of sugar and non-sugar molecules in honey crystallize around the crystal nucleus according to certain rules. No matter how greasy the crystal honey is, it is also a crystal combination visible to the naked eye. Although it is difficult to see the edges and corners of the honey crystal because it is soft, it is clear at a glance that the particles in the natural section of the crystal honey are dense. The taste without particles is doubtful; Those coarse hard crystals with liquid phase are abnormal; Uniform and dense particle aggregation is a typical crystalline state. 3. Diversity The diversity of honey crystals means that the honey crystal particles are different in thickness and hardness. The national standard "Honey" has different classifications such as coarse grain, slightly coarse grain, fine grain and fine grain. What we observe in production practice is more diverse, from grains as coarse as sand to grains as fine as fat. And the same particle size, butter and loquat are similar, buckwheat and pepper are loose; The same delicacy, acacia and wild osmanthus are thin and soft, while rape and wild peas are sticky. The hardness of honey crystals is also very different. Twist by hand, some are soft and slag-free, some are thick and hard, and it is difficult to melt with sand. If you taste it with your mouth, it is dense and thin, thick and hard. But in general, honey crystals are soft, and sand is big and hard, which is only an individual phenomenon. I have to mention that there are many books, magazines and even TV programs that teach people to distinguish between true and false honey by brushing it or not. Hand twisting is often used, saying that it is hand twisting to crystallize honey, and if it is difficult to granulate, it is totally unscientific to mix (white sugar) honey. Unless the adulterer directly mixes white sugar powder into the crystal honey, this will be the result, but is this possible? Really adulterated honey or fake honey, the result should be no crystals or loose crystals with low viscosity. 4. The crystallization of temperature-limited honey is generally formed naturally at room temperature. The temperature is low in autumn, winter and spring, and all honey is easy to crystallize; The temperature is high in summer, and the newly produced honey is generally not easy to crystallize, or the crystallization is very shallow. The temperature range of honey crystallization is more than 0℃ and less than 40℃. It is generally considered that 13- 14℃ is the optimum temperature, but the requirements of different varieties of honey for crystallization are quite different. Honey that is not easy to crystallize, such as jujube flower and acacia, will slowly crystallize after the continuous low temperature in late winter, while honey that is easy to crystallize, such as rape and wild bazi, will always crystallize quickly within a few days after being taken out of the hive. Within the crystallization temperature range of honey, if the honey temperature is greater than or less than the optimum temperature, the crystallization speed will slow down accordingly, and it will not crystallize beyond this range. However, once honey is crystallized, its natural melting process will be longer and generally cannot be completely melted; Especially honey seeds that are very easy to crystallize, such as rape, will remain crystallized all year round, and only in summer will they become thinner and softer, and some melted liquid honey may appear on the surface. Crystalline honey can be completely melted only when the continuous temperature is above 40℃. Generally, the naturally melted part of crystallized honey will not crystallize again after high temperature in summer. This is because the melting part is not the dissolution of the whole crystal particle, but the free sugar molecules and water molecules around the crystal nucleus, and there is no crystal nucleus necessary for crystallization. 5. The crystallization of physical honey is a form in which its constituent molecules move regularly at low temperature, but the external morphology changes, just like water turns into ice, which is a physical phenomenon. In addition to temperature, the physical factors that affect honey crystallization are the ratio of fructose to glucose and water. The smaller the ratio of fructose to glucose, the easier it is to crystallize with less water. Crystalline honey has no inherent quality change, and it is not too inconvenient to eat. Only a few varieties taste rough directly, that's all. We should respect nature and pursue the original ecology. It is not advisable to realize the crystallization of honey at the expense of destroying its composition and original structure (even adulteration). The national standard "Honey" clearly stipulates that chemical or biochemical treatment methods should not be used to change the crystallization of honey. It seems that physical heating is allowed. In fact, the crystallized honey will be recrystallized after heating and melting, and the shape and taste of the crystal will change. Especially the heating process will inevitably destroy some active ingredients in honey, such as VC, salivary gland hormones, enzymes and so on. Appendix 1) Rapeseed honey is the largest commodity honey in China, accounting for 40% of the total annual output. The crystal is milky white, delicate and firm. Rapeseed honey with coarse particles and poor looseness and viscosity is either fully brewed by bees or mixed with fake honey. 2) Crystalline particles tend to turn round and agglomerate, or like small grains of rice, they harden and appear alternately with liquid honey, which is artificially concentrated honey or honey after high temperature treatment. Most of them can't crystallize as a whole, and often condense on the bottom or wall of the bottle, slightly like mountains or corals. There is no water to divide the interface between crystalline honey and liquid honey (the interface may be the melting state of crystalline honey or the crystallization of immature honey). 3) thick as crystal, but without the crystal structure of honey; Others crystallize like stones and need to be broken into pieces before they can be sold. These are fake honey. 4) The honey that never crystallizes is fake honey, mixed with fake honey or specially treated.