Study On The Effect Of Postharvest Treatments On Quality And Wine Fermentation Of Maca

Maca(Lepidium meyenii Walp.)was a rare medicinal and edible economic plant,it had abundant nutritional value and health care efficacy,which made it had very high value for development and broad application prospects,because the effect of the unique characteristics of maca.Domestic and foreign researchers had done a lot of research work on the maca chemical composition,pharmacological activity,health food development and effectiveness of the composition detection,with the exception of maca post-harvest processing and quality control of raw materials.The glucosinolates content in commercialization of maca powder was very low,there may be the process of drying and milling processing leads to glucosinolate decomposition by myrosinase,so the enzyme need for inactivation immediately after postharvest.The effect of different storage and drying methods on the quality of maca was unclear.There was high content of starch in maca,whether the individual health wine into nutrient-rich could fermented do not add sugar,these were very interesting research work.In order to fill gaps in research in this area,the myrosinase passivation of maca,fresh tuber storage,fresh tuber drying and maca powder alone made health wine fermentation were carried out in the following research.(1)Enzymes inactivation of maca tuber : The maca tuber were treated by microwave radiation and high temperature short time steam blanching(HTSTSB),and then the myrosinase activity and nutrient quality index of maca were detected,the results show that the passivation of microwave radiation and HTSTSB can be used to the myrosinase passivation of maca tuber.The optimum conditions of microwave were as followed: the microwave intensity treatment at 14W/g and a material-to-liquid ratio of 2:1 for 60 s,the myrosinase in maca would thoroughly inactivate.The optimum conditions of HTSTSB were obtained as follows: steam pressure was 0.35 MPa,steam processing time was 50 s,and the material capacity was 240 g.Under the optimal conditions,the myrosinase activity of maca was lowered to 1.96%,and the retained content of glucosinolates could reach to 0.98%.Nutrients were retained more by HTSTSB compared to hot water blanching and microwave blanching.The myrosinase activity of maca could be effectively passivated by HTSTSB,and sensory quality was better maintained after treatment.Compared with conventional blanching,HTSTSB had a clear advantage.(2)Maca tuber storage: Two ways of refrigeration and freezing for the maca tuber storage.During storage,physiological,nutritional quality and texture change trend properties were determined respectively.The results show that temperature was one of main factors affecting the quality of maca root after mining,from extending the maca tuber storage life and maintain product quality point of view,the maca tuber should circulation at low temperature storage as far as possible,in order to obtain good quality.The results showed that: When maca tuber short-time refrigerated,low temperature storage(4?)can maintain the quality of its appearance,texture characteristics and reduce the loss of nutrients.A good quality could still maintain for 14 d storage,the content of soluble protein,soluble solids and glucosinolates were maintained more.Furthermore,myrosinase activity and the brown rate could be effectively inhibit at lower temperature storage.The texture profile analysis(TPA)was applied for the determination of texture characteristic of maca tubers under 4?and 20?were measured by Texture Analyzer.Results indicated the texture changes of maca tubers stored at 4?significantly slow speed at 20?,and low temperature storage should be used to ensure the quality of maca tubers.When maca tuber long-term frozen storage,the tuber frozen for 12 months at-5?,-10? and-20?,to find the three frozen samples appearance quality was still fresh and the textural properties well,this shows that the three temperature freezing were able to make the preservation period of maca tuber for over 1 years,and with the decreasing temperature frozen,the slower rate of decline in quality.Maca tuber frozen at-5?,the loss of nutrients was significantly higher than-10?and-20?,at the same time lower the temperature,the better to maintain the texture characteristics.(3)Maca tuber drying: In this study,the fluidized bed drying method of maca tuber was adopted.Through single factor test,the influence of three main factors including air inlet temperature,air flow and material particle size on the glucosinolate content and the saturation value of the maca tuber were investigated.Setting the glucosinolate content as the response value,the response surface methodology(RSM)and optimization were performed,to establish the regression model for the influence of fluidized bed drying of maca tuber on its glucosinolate content.The results showed that,when the air inlet temperature was 65 ?,air flow was 150 m3/h and material particle size was 3 mm,the highest glucosinolate content of maca with good sensory quality was achieved.(4)Maca fermented wine: Maca wine fermentation process(solid to liquid ratio,temperature,adding amount of yeast)were optimized by response surface methodology.The best wine fermentation conditions were as follows: fermentation temperature 25?,solid-liquid ratio 1:8,0.95% of the amount of yeast inoculation,the conditions resulting the maca wine alcohol production 41.16mL/100 g,glucosinolates leaching rate of 57.53%,the alkaloids leaching rate of 42.71%.The process had been fermented a maca wine displayed brownish red color,it had a slightly mellow,special smell of maca and harmonious body.This product was a low-alcohol nutritional wine that was in accordance with modern people's health concept.Through the study postharvest processing technology and Wine Fermentation of maca,in order to maximize the retained its biological activity,improve the healthy food quality of maca,so as to create the best economic benefit.