Preparation of umami peptides from chicken breast by ultrasound-assisted gradient dilution feeding substrate and study of their formation mechanism

Gradient dilution feeding substrate (GDFS) is regarded as an effective method for the production of active peptides, as it compensates for substrate limitations and minimizes substrate contamination of the ultrafiltration membrane. This study further investigated the impact of ultrasound-assisted gradient dilution feeding substrate (UA-GDFS) on the peptide yield and the intensity of umami. The chicken breast was used as ingredients. The umami compounds in the hydrolysate were determined using an automatic amino acid analyzer and HPLC. The hydrolysate's umami intensity was determined by electronic tongue in all modes. These findings indicated that UA-GDFS enhanced the umami intensity and peptide yield. Hydrolysate from UA-GDFS with molecular weight below 1 kDa was analyzed by nano-scale liquid chromatography-tandem mass spectrometry (Nano-HPLC-MS/MS). Electronic tongue analysis showed that GPSGPVG and VDGPSGK had umami taste and could enhance the umami taste of monosodium glutamate (MSG) solution. Asn68 and His145 were important sites on T1R3 for umami peptide binding.