Protein, polysaccharide and oil are the three major material bases of life and essential nutrients to maintain life. Dietary fiber is indispensable for healthy diet. Fiber plays an important role in maintaining the health of the digestive system. At the same time, taking enough fiber can also prevent cardiovascular disease, cancer, diabetes and other diseases. According to the National Standards of the People’s Republic of China and relevant literature, the crude protein, carbohydrates, oils, pigments, ash, crude fiber and other components in Chlorella vulgaris were determined.

The measurement results showed that the polysaccharide content in Chlorella vulgaris was the highest (34.28%), followed by oil, accounting for about 22%. Studies have reported that Chlorella vulgaris has an oil content of up to 50%, indicating its potential as an oil producing microalgae. The content of crude protein and crude fiber is similar, about 20%. The protein content is relatively low in Chlorella vulgaris, which may be related to the cultivation conditions; The ash content accounts for about 12% of the dry weight of microalgae, and the ash content and composition in microalgae are related to factors such as natural conditions and maturity. The pigment content in Chlorella vulgaris is about 4.5%. Chlorophyll and carotenoids are important pigments in cells, among which chlorophyll-a is a direct raw material for human and animal hemoglobin, known as “green blood”. Carotenoids are highly unsaturated compounds with antioxidant and immune enhancing effects.

Quantitative and qualitative analysis of fatty acid composition in Chlorella vulgaris using gas chromatography and gas chromatography-mass spectrometry. As a result, 13 types of fatty acids were determined, among which unsaturated fatty acids accounted for 72% of the total fatty acids, and the chain lengths were concentrated in C16~C18. Among them, the content of cis-9,12-decadienoic acid (linoleic acid) and cis-9,12,15-octadecadienoic acid (linolenic acid) were 22.73% and 14.87%, respectively. Linoleic acid and linolenic acid are essential fatty acids for life metabolism and are precursors for the synthesis of highly unsaturated fatty acids (EPA, DHA, etc.) in the human body.

Data shows that essential fatty acids can not only attract moisture and moisturize skin cells, but also prevent water loss, improve hypertension, prevent myocardial infarction, and prevent cholesterol induced gallstones and arteriosclerosis. In this study, Chlorella vulgaris is rich in linoleic acid and linolenic acid, which can serve as a source of polyunsaturated fatty acids for the human body.

Studies have shown that a lack of amino acids can lead to malnutrition in the human body and result in various adverse reactions. Especially for elderly people, a lack of protein can easily lead to a decrease in globulin and plasma protein, resulting in anemia in the elderly.

A total of 17 amino acids were detected in the amino acid samples by high-performance liquid chromatography, including 7 essential amino acids for the human body. In addition, tryptophan was measured by spectrophotometry.

The amino acid determination results showed that the amino acid content of Chlorella vulgaris was 17.50%, of which essential amino acids were 6.17%, accounting for 35.26% of the total amino acids.

Comparing the essential amino acids of Chlorella vulgaris with several common food essential amino acids, it can be seen that the essential amino acids of Chlorella vulgaris are higher than those of corn and wheat, and lower than those of soybean cake, flaxseed cake, sesame cake, fish meal, pork, and shrimp. Compared with common foods, the EAAI value of Chlorella vulgaris exceeds 1. When n=6>12, EAAI>0.95 is a high-quality protein source, indicating that Chlorella vulgaris is an excellent plant protein source.

The results of vitamin determination in Chlorella vulgaris showed that Chlorella powder contains multiple vitamins, among which water-soluble vitamin B1, vitamin B3, vitamin C, and fat soluble vitamin E have higher contents, which are 33.81, 15.29, 27.50, and 8.84mg/100g, respectively. The comparison of vitamin content between Chlorella vulgaris and other foods shows that the content of vitamin B1 and vitamin B3 in Chlorella vulgaris is much higher than that in conventional foods. The content of vitamin B1 and vitamin B3 is 3.75 and 2.43 times that of starch and lean beef, respectively; The content of vitamin C is abundant, comparable to chives and oranges; The content of vitamin A and vitamin E in algae powder is relatively high, which is 1.35 times and 1.75 times that of egg yolk, respectively; The content of vitamin B6 in Chlorella powder is 2.52mg/100g, which is higher than that in common foods; The content of vitamin B12 is lower than that of animal foods and soybeans, but higher than other plant-based foods, because plant-based foods often do not contain vitamin B12. Watanabe’s research found that edible algae are rich in vitamin B12, such as seaweed which contains biologically active vitamin B12 with a content ranging from 32 μ g/100g to 78 μ g/100g dry weight.

Chlorella vulgaris, as a natural and high-quality source of vitamins, is of great significance in improving the physical health of people with vitamin deficiencies when processed into food or health supplements.

Chlorella contains abundant mineral elements, among which potassium, magnesium, calcium, iron, and zinc have the highest content, at 12305.67, 2064.28, 879.0, 280.92mg/kg, and 78.36mg/kg, respectively. The content of heavy metals lead, mercury, arsenic, and cadmium is relatively low and far below the national food hygiene standards (GB2762-2012 “National Food Safety Standard – Limits of Pollutants in Food”), proving that this algal powder is safe and non-toxic.

Chlorella contains various essential trace elements for the human body, such as copper, iron, zinc, selenium, molybdenum, chromium, cobalt, and nickel. Although these trace elements have extremely low levels in the human body, they are essential for maintaining some of the decisive metabolism in the body. Iron is one of the main components that make up hemoglobin, and iron deficiency can cause iron deficiency anemia; Selenium deficiency can cause the occurrence of Kashin Beck disease, mainly in adolescents, seriously affecting bone development and future work and life abilities. There have been reports abroad that a decrease in the total amount of iron, copper, and zinc in the body can reduce immune function and promote bacterial infections. Chlorella is rich in various mineral elements, indicating its potential as an important source of essential trace elements for the human body.