HPLC results from Rachel retrived 20160822

Comparative analysis of critical compounds in YE by HPLC

Samples:

Kerry YE, Angel YE, in-house YE (from yeast with different growth conditions)

--in-house YE

   The basic recipe is molasses 8%, peptone 3%, antifoam 0.1%, pH 5, air pump gear 3, temperature 30 degree. The description of YE3&YE11 is showed as below:

YE3   -- Air pump gear 6 

YE11 -- 3% Peptone replaced by 15g/L (NH4)2SO4

Autolysis conditions: 50 degrees, 200rpm, 24h

Methods: 

  -- C18 column, UV detector at 254nm

  -- Standards

   0.1% w/v in deionized water

  -- Sample treatments

   2.5% w/v in deionized water, filtered with 0.22µm nylon filter

  --Mobile phases

  A: 50 mM phosphate buffer (pH 5.8)

  B: methanol

  --Flow rate: 0.4 mL/min. 

  --Gradient program

0–5 min 0% A;

6–20 min, 0-20% A;

21-25 min, 20% A;

26–40 min, 20-0% A;

41-50 min, 0% A

Results:

Discussion;

5'GMP was found in Kerry YE. Meanwhile, there was no significant peak in the 5'IMP position.  
Two in-house YE samples 1&3 which extracted from yeasts grown in different conditions gave similar chromatography. Compared to Kerry YE, they gave a peak in 5' IMP, but none in 5' GMP. 
The chromatography of Kerry YE and Angel YE were also compared. The results showed there were several different peaks between these two products, which were marked by blue circles in the figure. These components need to be further studied and identified, which may explain the flavor difference between these two products.