Evaluation of nutritional and health benefits of oyster mushroom.

Abstract

“Evaluation of nutritional quality and health benefits of oyster mushroom” (Pleurotus florida) was a comprehensive study undertaken to determine the nutritional quality, nutrient losses during processing and also to investigate the impact of mushroom supplement on the blood profile of the subjects with specific disease condition.

The energy value of oyster mushroom was 453.0 kcal/100 gm on dry weight basis and that of carbohydrate, protein and fat content were 4.7 g, 5.6 g and 0.8 per cent respectively in fresh weight basis. As reported by earlier researchers oyster mushrooms are low in calories, with low carbohydrate and fat content.

Oyster mushroom contains all the essential amino acids, and the content of phenyl alanine was exceptionally high when compared to the reference protein. Similarly leucine, lysine and threonine content were also found to be higher than the reference protein. Among the other amino acids present, glutamic acid was remarkably high (17.2) followed by aspartic acid and tyrosine.

Amino acid content and amino acid score (AAS) clearly confirmed that oyster mushroom is superior in protein quality with respect to amino acid composition and essential amino acid content when compared to P.citrinopeleatus and P.sajor caju. Essential amino acid (EAA) index of oyster mushroom determined was found to be 119 while the nutritional index based on protein quality was estimated as 6.42.

Oyster mushroom contains, B complex vitamins viz thiamine, riboflavin and niacin as 5.43 mg, 8.7 mg and 55.9 mg per 100 g respectively which is fairly very high when compared to other plant foods. However vitamin C content of oyster mushroom was found to be comparatively low(12.4 mg/100 gm).

Investigation clearly revealed that oyster mushrooms are rich source of various minerals. Calcium content was recorded as 12.46 mg/100 gm. While sodium, potassium and phosphorus were found to be 125mg, 623 mg and 477 mg per 100 gm respectively. Oyster mushroom also contains fairly good amount of iron(7.63 mg/100 gm). Trace elements analyzed viz copper and zinc was estimated as 1.9mg and 1.47 mg/100 gm of oyster mushroom.

Oyster mushroom contain 90.3 percent moisture which promote its susceptibility to deterioration. As observed in other mushrooms fiber content of oyster mushroom was 3.2 g/ 100 gm. Tannin and polyphenol which are considered as antioxidants were determined as 1.4mg and 4.3 mg /100 gm respectively.

Vitamin C and zinc are considered as IF positives present in oyster mushroom. Anti oxidants such as polyphenols, tannins and fibre were also present in oyster mushroom studied which account for their medicinal value.

On assessing the loss of nutrients in oyster mushroom when subjected to various methods of processing it was revealed that as expected all the macro nutrients decreased during processing such as boiling, blanching and steaming while dried mushroom depicted enhanced values. It was noticed that the dried mushroom (T4) was superior to all the other processing treatments, with respect to various nutrients. As the moisture is lost from the mushroom, nutrient concentration increases and hence dried mushroom recorded higher values for nutrients per100 grams. Boiling method recorded the maximum nutrient loss while steaming, the lowest.

Health benefits of oyster mushroom was ascertained through supplementation study on human volunteers with specific disease condition. Dried mushroom powder formulated was distributed to the subjects under case study on the basis of 5gm/person/day for a period of three months. Incorporation of mushroom supplement was accomplished without any difficulty in the subjects. The result of the blood profile of those subjects showed a significant decrease in the blood glucose and blood cholesterol levels in the subjects over a period of three months. Impact of the supplement on the blood pressure was not very much apparent with a short spell of supplementation.

To conclude, oyster mushroom is superior in nutritional quality and highly suitable and beneficial for promoting and maintaining health. The study also recommend that cultivation and consumption of oyster mushroom should be popularized and promoted with the motto “mushroom for nutrition health and income”.