Atma Jaya Catholic University of IndonesiaMushrooms consist of several types, but only a few types that can be consumed by humans.In general, colorful mushrooms are mushrooms that cannot be consumed by humans.Several types of mushrooms that can be consumed include edible mushrooms (Volvaria volvacea), shitake mushrooms (Lentinus edodes), oyster mushrooms (Pleurotus ostreatus), lingzhi needles (Gonoderma lucidum), and ear mushrooms (Auricularia auricula) (Widyastuti & Tjokrokusumo 2021) .The mushroom that will be discussed in this article is the oyster mushroom with the Latin name, namely Pleurotus ostreatus.Oyster mushrooms consist of about 40 species and are included in the type of wood fungus because this fungus grows in media or sawdust.Therefore, oyster mushrooms are often found in places of wood.This mushroom has a delicious taste, has a fairly cheap price, is easy to find in the market, and has a high nutritional content.In addition to having a high nutritional content, this mushroom also has medicinal properties and can improve health.Oyster mushrooms, which belong to the genus Pleurotus, have long been cultivated by humans and used as medicinal mushrooms.This is because this fungus has several nutraceutical compounds or compounds that have pharmacological properties (Widyastuti & Tjokrokusumo 2021).The nutritional content, nutraceutical components, and health benefits of consuming oyster mushrooms will be discussed further in this article.Figure 2 Nutrient content of oyster mushrooms.The nutritional content of oyster mushrooms can be said to be quite complete and high.Oyster mushrooms contain as much as 73.7-92.2% water content, 50.7-81.8% carbohydrates, 10.5-44% total protein, 7.5-12.4% fiber, 6.1-9, 8% ash, 1.1-2.4% protein, and 245-367 Kcal calories.In addition, oyster mushrooms also contain several vitamins, such as niacin as much as 109 mg/100 g, vitamin C as much as 30-144 mg/100 g, vitamin B complex as much as 1.7-4.8 mg/g, vitamin D, vitamins K, folic acid, riboflavin, and thiamine.Mineral content in oyster mushrooms, including zinc (Zn), magnesium (Mg), copper/ cuprum (Cu), manganese/ manganese (Mn), potassium (K), iron (Fe), selenium (Se), phosphorus ( P), and calcium (Ca).Oyster mushrooms also have a lot of amino acids, 100 grams of oyster mushrooms contain 0.3 g of isoleucine, 6.8 g of threonine, 6.3 g of valine, 2.1 g of methionine, 0 tryptophan. ,3 g, 2.61 g tyrosine, 4.1 g phenylalanine, 17 g glutamic acid, 9.3 g aspartic acid, 6.3 g serine, 5.4 g proline, 6.3 g lysine g, 12.6 g of leucine, 2.4 g of histidine, 5.9 g of glycine, 0.6 g of cystine, 6.3 g of arginine, and 7 g of alanine.The higher and more amino acid content, the higher the nutritional content in oyster mushrooms.Therefore, oyster mushrooms are often used as traditional medicine.In addition to high nutritional content, oyster mushrooms also have many bioactive metabolites that can be used in making medicinal or pharmaceutical products (Widyastuti 2013).The health benefits obtained when consuming oyster mushrooms, among others, can stimulate the immune system so that it is less susceptible to various diseases, can treat diabetes, cancer, and various microbial infections.In addition, oyster mushrooms are also proven to prevent and treat diseases of red blood cell deficiency or anemia.This is because oyster mushrooms also contain nutraceuticals or pharmacological compounds, including lectins with immunomodulatory activity, polysaccharides for anti-cancer and immunoenhancing, phenolic compounds as antioxidant activity.Antioxidants are substances that can prevent and slow down the oxidation process.Antioxidants are compounds that can protect cells from free radicals both from outside and inside the body.Its ability to prevent free radicals will protect the body from various diseases related to free radicals such as cancer.Another nutraceutical component in oyster mushrooms is beta glucan as an immunomodulator to increase the immune response so that it can function as anti-tumor and anti-cancer that can prevent tumors and cancer (Widyastuti & Tjokrokusumo 2021).So in this article, we will focus on the content of beta glucan which acts as an immunomodulator and functions as an anti-tumor and anti-cancer.Beta glucan is a secondary metabolite compound and is a glucose homopolymer whose binding is via beta-(1,3) and beta-(1,6)-glucoside bonds.This compound is often found in the cell walls of fungi, one of which is oyster mushrooms.Oyster mushrooms are referred to as a source of biologically active glycans which are often used as supplements because they have immunosuoresan activity that can suppress the work of the immune system.Based on the Food and Drug Administration (FDA), beta glucan is a compound that is safe for consumption, has no poison, and has no side effects so that it can be consumed freely.The beta-glucan compound found in oyster mushrooms is pleuran (beta-1,6 and beta-1,3-glucan).Beta glucan can act as an immunomodulator that can increase the immune response so that it has functions as anti-tumor, anti-cancer, anti-cholesterol, antioxidant, and anti-aging.This beta glucan compound consists of several types and is found in other types of mushrooms as well.Several beta-glucan compounds, including lentinan (beta-1,6 and beta-1,3-glucan) found in shiitake mushrooms (Lentinus edodes), cellulose (beta-1,4-glucan), and pleuran (beta-1 ,6 and beta-1,3-glucan) contained in oyster mushroom (Pleurotus ostreatus) and edible mushroom (Volvaria volvacea) (Widyastuti 2013).So, what is the mechanism so that beta glucan acts as an immunomodulator and functions as an anti-tumor and anti-cancer?The benefits of beta glucan as an immunomodulator have a mechanism by stimulating the body's defense system, namely by activating macrophages which aim to capture and destroy foreign objects that enter the body, such as bacteria, fungi, parasites, and viruses.Thus the body can fight these foreign objects so that the immune response and the immune system will increase due to the presence of macrophages that can help fight.In addition, by increasing the immune system, it can act as anti-cancer and anti-tumor as well.The mechanism of beta glucan as anti-cancer and anti-tumor is also by activating macrophages, NK cells, and T lymphocyte cells that aim to secrete or secrete cytokines, such as IFN-gamma, TNF-alpha, and IL-1beta.These cytokines have properties that can inhibit the proliferation of tumor cells, can induce apoptosis, and can differentiate tumor cells (Widyastuti 2013).Thus, oyster mushrooms which have nutraceuticals in the form of oyster mushrooms can be useful for increasing the immune system, preventing cancer, and preventing tumors.If so, do you have to eat oyster mushrooms raw in the form of oyster mushrooms?Or are there processed food products?The answer is that many oyster mushrooms have also been processed into processed food.This is because in addition to having a delicious taste, this mushroom also has a high nutritional content so that it has many health benefits as described above.Nowadays, most people are already concerned about their health, so when choosing food, it is not only about good taste, or easy to eat, or easy to prepare, but they also look for foods that are high in nutritional content and have health benefits.Therefore, there are many processed foods that use oyster mushrooms as their basic ingredients so that they can increase the selling value of oyster mushrooms.Examples of processed foods with basic ingredients in the form of oyster mushrooms include crispy mushrooms, burgers, peppers, meatballs, mushroom steaks, peppers, nuggets, sausages, dumplings, shredded, crackers, chips, health drinks, and flavorings.Oyster mushrooms contain glutamic acid so that they can be made into natural flavorings that are safe for health (Widyastuti 2013).One of the commercial products that can be found in e-commerce such as Tokopedia and using the basic ingredients of oyster mushrooms is Mushome Chips Oyster Mushroom Chips Vegan & Vegetarian Friendly Barbeque.This product is processed in the form of chips such as chiki so that it can be consumed as a snack as well.Images of these commercial products can be seen in the image below.