| Waste beer yeast is the main by-product of main fermentation and sub-fermentation in the beer industry,which contains proteins,carbohydrates,RNA,B vitamins,glutathione,and abundant amino acids and numerous minerals.It has High economic value and utilization value.At present,most of the brewer's yeast used in feedstuffs are directly discharged.Not only are the active ingredients not used properly,but also they cause serious environmental pollution.This study is closely related to the optimization of industrial waste yeast broken-wall,glutathione separation and purification process;After yeast autolysis wall-breaking and enzymatic auxiliary treatment,glutathione extraction by hot water extraction method,response surface methodology analysis was used to determine the optimal extraction process.Besides,ion exchange chromatography was applied to separate and purify glutathione.The antioxidant activity of glutathione was evaluated and a stable,rapid and efficient method for the determination of glutathione content was established.The main findings were as follows:1.To determine the optimal extraction conditions,beer waste yeast was used as raw material,and the key factors affecting yeast autolysis,such as temperature,pH value,papain addition amount,and reaction duration,were optimized through single-factor test and orthogonal test.The results showed that the optimal conditions were: temperature 48 ?,pH value 5.8,papain addition of 1 % of yeast slurry,and the reaction duration was 26 h.Under this condition,the protein dissolution ratio was 41.72 % and the sugar content was 17.92 %.2.The extraction process of zymosan was optimized and the influence of factors such as alkali concentration,extraction temperature,and extraction duration was optimized using the Software DesignExpert and response surface methodology.The optimum conditions for alkali dissolution were: alkali extraction temperature 90.59°C,alkali extraction duration 62.46 min,alkali concentration 3.11%,feed water ratio 1:16,sugar extraction ratio 44.11%.The result is not far from the expected value,indicating that the model is more suitable.The crude polysaccharide has the ability to scavenge DPPH and hydroxyl free radicals.3.In order to determine the optimal technological conditions for the extraction of reduced glutathione from waste yeast by hot water extraction,based on the single factor test,the key to influencing the extraction of glutathione from yeast by the Central-Composit Design response surface method was used.Factors such as the amount of acetic acid,heating duration,heating temperature and material-water ratio were optimized.Through the establishment of the quadratic regression model,the optimum extraction process conditions were: 5.0 % acetic acid dosage,1:20 of feed water ratio,heating duration 6.00 min,and heating temperature 85 ?.Glutathione was extracted under this condition and repeated three times.The average extraction ratio was 0.3728 % and the deviation was 0.001 %.The results showed that the extraction of glutathione from yeast and hot water extraction method are the most efficient,time-consuming and economical,non-polluting methods.It is the first choice for the extraction of glutathione from yeast.4.The glutathione in brewer's yeast was purified by macroporous resin D001,and static and dynamic adsorption rules were studied,respectively.The results showed that the best conditions for separation and purification of GSH from waste beer yeast were as follows: the elution buffer was 0.2 M phosphate buffer and the elution flow rate was 2.0 m L/min.After purification,glutathione was white and the recovery was 75.85 %.And GSH showed good antioxidant activity.When 0.3 mg/m L GSH was added,the hydroxyl radical scavenging rate was as high as 76.2 %;when the GSH concentration was 0.6 mg/mL,the maximal clearance ratio was 66.24 %. |
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