Development And Industrial Production Of Pitaya Vinegar

In this dissertation,fermented pitaya vinegar and pitaya vinegar beverage were developed and researched industrial production using pitaya from Guizhou Guanling.The study has primarily researched the questions including the criteria of raw materials purchasing,pretreatment process,selection of acetic bacteria,optimizing of acetic acid fermentation process,the optimum formula of pitaya vinegar beverage,selection of equipment for industrial production,control indicators of production.The main work and conclusions are as follows:Through a small number of trials in laboratory,the criteria of raw materials purchasing was determined as follows choosing pitaya unscathed with 90% maturity,fruit diameter greater than or equal to 7 cm and the content of soluble solids 10-15°BX;using the knife type juicing,adjusting the concentration of pitaya juice to soluble solids to be 9°BX,the optimal conditions of the pectinase hydrolysis: adding 0.5% pectinase(enzyme activity: 30 000U/g)and hydrolyzing for 3 h at 55?.the optimal conditions of juice sterilization: sterilizing for 15 min at 85?;initial sugar content 23°BX,inoculating amount of Angel yeast BV 818 0.04%,fementing for 7 days at 22?.Under the fermentation conditions,the alcoholicity of pitaya original wine was 13 %(V/V).The LB1 acetic bacteria was chose as the strain of pitaya vinegar acetic fermentation.The best technological conditions of acetic fermentation were as follows 8%(V/V)initial alcohol degree,initial pH 3.5,10% inoculums amount,180 r/min,30? 5 d,and under the fermentation conditions,the titratable acid content of original pitaya vinegar was 5.30 g/100 mL with high sensory quality;The titratable acid content of original pitaya vinegar was 6.34 g/100 mL in an enlarged test(30 L)of fruit vinegar starter,and the production process conditions and parameters of pitaya vinegar beverage industrial production was determinated preliminarily.The major factors recipe of adjusted by fermented original pitaya vinegar was determined that: 8% pitaya original vinegar,4% sugar,2% xylitol.Based on the major factors recipe,adding other secondary factors gradually with smaller quantities,the eventually recipe of pitaya vinegar beverage with good mouthfeel was determined combining with sensory evaluation.Based on the technological process of pitaya wine and vinegar fermentation determined by small test results,according to the selection principle of equipment,combining with theoretical calculation about expected annual production of pitaya vinegar,the main equipment of industrial production was chose after market research.The main key control points which had been identified through debugging(2 t)and pilot(5 t)production were as follows choosing pitaya with 80% maturity,the conditions of the pectinase hydrolysis: adding 0.5% pectinase and hydrolyzing for 2±0.5 h at 50±1?,initial sugar content 23°BX,inoculating amount of Angel yeast BV 818 0.04%,fementing for 7 days at 22?.Under the fermentation conditions,the alcoholicity of pitaya original wine was 13%(V/V);adjusting initial alcoholicity content 8%(v/v),initial pH 3.5,10% inoculums amount of LB1 acetic bacteria were activated at the first time in vinegar fermented grains slot for 6-7 d,then pitaya vinegar was fermented on the way of the self-priming semicontinuous fermentation through discharging half of fermented liquid form acetate grains and feeding half of 8%(v/v)pitaya wine in 5t acetic fermentor;The scope of the control parameter during acetic fermentation were as follows temperature of fermentation 28-31?,the flow rate of oxygen 12±1 m3/h,the fermentation period 26-32 h.The original pitaya vinegar having the titratable acid 7.02 g/100 mL was produced.Transition rate of the acetic acid is 86.2%.Finally the quality of pitaya vinegar was analysised and the key control technical indicators which suited the small and medium production enterprise of pitaya vinegar were determined.The study could provide a reference for pitaya product development and lay a foundation for the production of fermented pitaya vinegar.