Amino acid composition and anti‐polyphenol oxidase of peptide fractions from sericin hydrolysate

Abstract

Sericin hydrolysate (SH), prepared from enzymatic hydrolysis of sericin, was investigated for its antipolyphenol oxidase (PPO) properties. SH decreased PPO activity from both purified mushroom PPO and extracts from apple and eggplant, and retarded browning in fresh-cut apple and eggplant. SH was a competitive inhibitor using catechol as a substrate. SH exhibited copper ion-chelating power and reducing power abilities. Fractionation of SH using size exclusion chromatography resulted in four fractions, designated as F1, F2, F3 and F4, with PPO inhibition of 35.75%, 3.89%, 24.52% and 14.75%, respectively. Ser and Asp were major amino acids found in F1. Amino acid sequences in F1, as investigated by LC-MS/MS using de novo sequencing, contained a high ratio of amino acids with chelating ability. Moreover, amino acids with reducing power ability and with antityrosinase ability were also identified in the sequences.Sericin hydrolysate peptides inhibit PPO A. Puangphet et al.977

Waste to Wealth: Exploring the Versatile Prospects of Discarded Silk Sericin

“…The polyphenol oxidase (PPO), peroxidase, and phenolic contents and browning enzymatic activity were reduced by the sericin treatment. Inhibition of PPO and browning was demonstrated by sericin hydrolysate 206 (SH), which was produced by hydrolyzing sericin using Alcalase. SH reduced PPO activity from extracts of apples by 95%, eggplant by 79%, bean sprouts by 70%, and banana flowers by 79%.…”

“…Figure shows the difference in the visual appearance of the selected fruit over 6 days. Several studies reported the capability of sericin to act against polyphenol oxidase from various sources and thereby control the browning of fresh-cut products. , Chimvareea et al examined the effect of sericin-based edible coatings on the browning of freshly cut mangoes during storage. The outcomes demonstrated that in comparison to the control, the sericin-coated fruit samples had reduced browning scores, browning indices, and enzymatic browning activity.…”

Extraction and antioxidant activity of sericin, a protein from silk

“…Similarly, biopeptides of sericin, obtained by enzymatic hydrolysis, exhibited a higher antioxidant potential compared to non-hydrolyzed sericin (Wu et al, 2008;Puangphet et al, 2015Puangphet et al, , 2018. According to Puangphet et al (2018), sericin biopeptides containing larger amounts of serine and asparagine present the most inhibitory effect (Puangphet et al, 2018). The type of protease used for the hydrolysis also influences the effect, where alcalase showed the best performance (Fan et al, 2010).…”

“…This effect is due to the presence of a high content of amino acids with hydroxyl groups, such as serine, asparagine and threonine acting as chelators (Micheal & Subramanyam, 2014). Furthermore, the hydrophobic section of these amino acids might contribute to their binding in the hydrophobic pocket near the active site of tyrosinase, causing its inhibition (Puangphet et al, 2018). These findings make the sericin an interesting candidate to retard the browning effect in foodstuff without the addition of synthetic antioxidant compounds.…”

Enzymatic valorization process of yellow cocoon waste for production of antioxidative sericin and fibroin film

“…Several studies have reported bioactive peptides from different sources such as fish, 14 buffalo, bovine casein 15 and sericin hydrolysates, 11,16,17 which exert antioxidant activity, tyrosinase and lipid peroxidation inhibition activity. However, there is little knowledge on the identification of bioactive peptides from sericin hydrolysate 17 . In this current study, a new strategy of yellow cocoon waste valorization by an enzymatic process using protease_SE5 (protease_SE5‐assisted hydrolysis) was performed and compared to the conventional methods of HTHP and 0.5% Na 2 CO 3 in terms of sericin hydrolysate production and the properties of fibroin film.…”