Study On The Preparation Of Siraitia Grosvenorii Fermented Drink And The Flavor Of Mogrosides

Siraitia grosvenorii possess nutritional and medicinal values,its fruit and its functional ingredient mogroside are widely used in foods and medicines.Fermented Siraitia grosvenorii wine presents unique flavors.The present fermentation process of Siraitia grosvenorii is time cosuming,and applies the germicide SO₂that may yield poor taste and health problems.Moreover,the mogrosides mixture used as sweetener present delayed initial sweetness,continuous sweet aftertaste and slight bitterness,which limits their application;while the mogrosides are still lack of the knowledge of their flavor for each mogroside due to the low content and difficulty in separation.In this paper,the preparation process of the wine was studied;the feasibility of replacing SO₂with the natural germicide lysozyme and the practicality of lysozyme in the preparation of wine were explored.The formulation of sweeteners was investigated to improve the taste of mogrosides.Subsequently,Discovery Studio was used to study the interaction between human taste receptors and mogrosides to predict the flavor of a single component mogroside.The main contents are as follows:1.The brewing process and flavor of fermented Siraitia grosvenorii wine were studied.The effects of initial sugar content of fruit pulp,species and inoculation amount of Saccharomyces cerevisiae,main fermentation temperature and time,post fermentation temperature and time on the physicochemical properties of Siraitia grosvenorii wine were investigated.The orthogonal test based on the single factor experiments was employed to optimize the fermentation process.The results indicate that the yeast addition,initial sugar content and main fermentation time are the main factors that influence the wine quality.The optimum main fermentation process with red and white yeasts was:the initial sugar content of fruit pulp was 13°Bx and 14°Bx,the inoculation amount of yeast was 0.7%and 0.5%,and the main fermentation temperature was 25? for 4 d and 5 d,respectively.The optimal post-fermentation process was 4? for 7 d.GC-MS analysis indicated that the flavor compounds in the fruit wine fermented by red wine yeast included L-ethyl lactate,isobutyl acetate,and 2-heptanone etc,which respectively imparted fruity,floral,and medicinal aromas to the wine.The flavor compounds produced by white wine yeasts were mainly isoamyl acetate and ethyl decanoate,which made the wine have a strong fruit flavor.2.The feasibility of replacing SO₂ with lysozyme in the preparation of Siraitia grosvenorii wine was explored,and the process conditions for lysozyme to degrade cellulose in fruit pulp were optimized.Using lysozyme to replace SO₂ was conducive to the increase of alcohol production in fermented fruit wine;the sensory evaluation showed that the taste of fruit wine with lysozyme as germicide was better than that with SO₂.In addition,the lysozyme did not inhibit the yeast activity,and exhibited an antibacterial effect similar to that of SO₂,which ensured the smooth progress of fruit wine fermentation.Lysozyme also degraded the cellulose in Siraitia grosvenorii pulp into glucose that is needed for fermentation.Through single factor experiment and response test,the optimal degradation conditions were:adding 0.04%lysozyme and reacting for 6 d at 56?.3.The flavor of mogrosides was optimized and adjusted.After preliminary screening,the mogroside with content of 50%mogroside V was used as the research object,and the taste was optimized through formulation.When the mogroside was formulated with stevioside,sucralose and aspartame,the best sweetener was mogroside(70%)+aspartame(23%)+sucralose(7%).Using acid and salty taste modifiers to further optimize the taste of the compound sweetener,and it was found that when 0.025%Na Cl was added to the sweetener aqueous solution,the taste of the compound sweetener was the best.Compared with mogrosides,the formulated sweetener provided a better taste when applied to black tea beverages.4.Discovery Studio was employed to molecularly dock the mogrosides and receptor protein.It was found that the total interaction energies between the mogrosides and the receptors present a significant correlation with the sweetness and bitterness of mogroside.There was a good positive correlation with the strength of sweetness.Therefore,a predictable sweetness model of mogrosides was established.Furthermore,analysis of the ligand-receptor docking conformation and interaction mode revealed that changes in the number of glycosylgroups at C-24 and C-3 positions would affect the flavor of mogroside,which was mainly due to the steric hindrance effect of the taste receptors.