Flavoring Preparation From Pleurotus Geesteranus Hydrolysates Through Maillard Reaction

There are many condiment products made from edible mushroom on the market due to its delicious taste.They are mainly dominated by edible mushroom extracts with monosodium glutamate,salt and other ingredients added.Although they possess some mushroom flavor,the characteristic aroma is not strong enough and the kokumi is insufficient.The output of Pleurotus geesteranus is high and the taste of it is delicious.The protein content of Pleurotus geesteranus is higher than general mushroom and it contains various amino acids,especially delicious amino acids such as glutamic acid and aspartic acid.In addition,hydrolysates of animal and vegetable protein source have become a focus for condiment development.In this paper,dried Pleurotus geesteranus was used as raw materials.Biological enzymatic hydrolysis technology and Maillard reaction technology were employed to develop a basic seasoning material which not only has mushroom characteristic flavor and meat flavor,but also can enhance the umami and kokumi taste of consomme.The main research contents are listed as follows:Based on the content of reducing suger and volatile compounds,the optimum hydrolyzation conditions of cellulase were determined as follows: the ratio of Pleurotus geesteranus to deionized water was 1:8.0.4%(w/w)cellulase was added and hydrolyzed for 2 h under pH 4.0 at 50oC.With degree of hydrolysis(DH)and sensory evaluation selected as indicators,the optimum conditions for neutral protease were determined as follows: neutral protease concentration was 0.5%(w/w)and hydrolysis time was 2 h.Under above optimum conditions,the DH of Pleurotus geesteranus enzymatic hydrolysates was 13.75%.After Maillard reaction,the mushroom flavor and umami of products were strong and the kokumi taste had been greatly improved.Using the optimum enzymatic hydrolysates as raw material,basic seasoning material with mushroom flavor was prepared from enzymolysis liquid-xylose-cysteine system through Maillard reaction.With sensory evaluation used as index to optimize the condition of Maillard reaction,the optimum Maillard reaction system was determined as follows: 6% cysteine and 10% xylose which were added according to the solid content of enzymatic hydrolysates,reacted at 115oC for 100 min under pH 7.4.The basic seasoning material prepared under above conditions showed prominent mushroom and meat flavor,with significant kokumi and umami taste.The smell was natural and gentle.The amino acid,nucleotide and volatile compounds of Pleurotus geesteranus enzymatic hydrolysates and basic seasoning material were compared.The amino acid and nucleotide analysis results showed that Maillard reaction improved the kokumi and kept the mushroom flavor and umami at the same time.And the GC-MS analysis results suggested that the flavoring had abundant characteristic volatile compounds through Maillard reaction.It proved that Maillard reaction can improve the meat flavor and can make the aroma of the flavoring pure and abundant.Correlation analysis between the sensory indexes and volatile compounds by partial least squares regression(PLSR)showed that the critical volatile compounds of the mushroom flavoring were thiazole,3-methyl-2-thiophenealdehyde,2-octenal,2,3-octanedione,nonenal,6-hydroxyhexan-2-one,pentanal,hexanol,2-octanone,2-butylpyridine,2-methyl-3-furanthiol,benzaldehyde,2-acetyl thiazole,furfural.The antioxidant activity of enzymatic hydrolysates and the basic seasoning material was also measured.The results showed that the reducing power and DPPH radical scavenging activity of the basic seasoning material were strengthened after Maillard reaction while its Ferrous chelating activity was reduced.