The whitening was mainly caused by the inhibitory effects of the broth on tyrosinase activity, whereas the active substances for anti-ageing and moisturising were the phenols, peptides and free amino acids.
As a micronutrient for human health, selenium has a detoxifying and antioxidant effect on the skin. It is also among the four internationally-recognised antioxidants that promote the breakdown of peroxides and protects haemoglobin in cells from damage.
On the other hand, the mung bean is an important legume that is widely planted in temperate and subtropical regions. It contains a myriad of potential bioactivities, like being antioxidant, anti-tumour and anti-bacterial.
The study titled The Whitening, Moisturizing, Anti-aging Activities, and Skincare Evaluation of Selenium-Enriched Mung Bean Fermentation Broth was published in the journal Frontiers of Nutrition.
“Since the cell walls of selenium-enriched mung beans are difficult to break (down) (the main components are cellulose and pectin), the various active substances in the cells cannot be fully utilised.
“Hence, biological fermentation can rupture the cell walls of tissues and break down macromolecular substances into small molecular substances, thereby releasing a variety of nutrients or active substances,” said the researchers.
To conduct the study, the researchers created a face mask with various ingredients and commissioned it to be produced by Shanghai Guzidi Industrial Co. Ltd. The cultures Lactobacillus helveticus and Bifidobacteria assisted the fermentation process.
The chemical composition of the broth was analysed to investigate the whitening, moisturising and anti-ageing activities of the broth. The free radical scavenging activity of mixture was assessed in vitro.
A clinical trial was conducted on 31 Chinese women aged 25 to 60 with no pigmentation disorder, illness, history of hypersensitivity and facial skincare use. The subjects used a broth masque for 15 to 20 minutes after cleaning their faces.
The results demonstrated that 13 free amino acids with small molecular weight were obtained from the broth, and the γ-aminobutyric acid (GABA), Glu, Arg, Ala, and Gly had the top five amino acid contents.
GABA was the dominant amino acid among the free amino acids in the broth, and its content was much higher than other amino acids (94.81%). Free peptides and protein hydrolysate comprise 17 amino acids, including seven essential amino acids.
The broth was rich in polyphenols, peptides, and γ-aminobutyric acid (GABA) and displayed significant free radical scavenging and tyrosinase-inhibiting activities. It also decreased the synthesis of melanin.
After four weeks of using the face mask, the subjects’ faces became fairer, with reduced wrinkles and increased moisture content.
“Selenium-enriched mung bean possessed the excellent whitening, moisturising, and antioxidant efficacy, which could lay a scientific foundation for the utilisation and development of skincare products of selenium-enriched mung bean and its related industrial cosmetics,” concluded the researchers.
Source: Frontiers in Nutrition
“The Whitening, Moisturizing, Anti-aging Activities, and Skincare Evaluation of Selenium-Enriched Mung Bean Fermentation Broth”
Authors: Kang Wei, et al.