苹果酵素天然发酵过程中代谢产物的变化规律

Changes in Metabolites during Natural Fermentation of Apple into Enzyme Drink

为研究苹果酵素天然发酵过程中物质代谢变化,对天然发酵过程中pH值、总酸、有机酸(乳酸、醋酸、苹果酸)、糖类(蔗糖、葡萄糖、果糖)、乙醇、总酚含量、1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除率的变化进行分析。结果表明,发酵过程中pH值从5.05降至3.88,总酸、乳酸含量呈不断上升趋势,乙酸质量分数由0.018%升至0.23%,苹果酸质量浓度在发酵前14?d由初值0.67?g/L上升至2.45?g/L后略微下降;葡萄糖、果糖质量浓度呈先升后降趋势,且二者均在发酵第21天达到最大值130.6、177.2?g/L,蔗糖质量浓度不断下降趋于0?g/L;乙醇在发酵14~21?d过程中产生,发酵4周后乙醇体积分数可达6.6%;总酚质量浓度与DPPH自由基清除率呈先升后降趋势,均在发酵第21天达到最大值为259.4?mg/L、90.9%。

The objective of this work was to analyze the changes in metabolites during the natural fermentation of apple into an enzyme drink. The pH value,total titrable acid,organic acids（lactic acid,acetic acid,and malic acid）,sugars（sucrose,glucose,and fructose）,alcohol,total phenolic content and 1,1-diphenyl-2-picryl-hydrazyl（DPPH） radical scavenging ability were investigated. Results showed that pH value decreased from 5.05 to 3.88 while total titratable acidity and lactic acid increased gradually during the fermentation process. Acetic acid was accumulated from 0.018% to 0.23% during the process; malic acid increased from 0.67 g/L to 2.45 g/L during the first 14 days and then decreased slightly. Glucose and fructose increased until reaching their maximum of 130.6 and 177.2 g/L on the 21^th day and then decreased,while sucrose kept decreasing to almost 0 g/L during the whole fermentation process. Alcohol was produced from the 14th to 21^th day,reaching 6.6% on the 28^ th day. Both total phenolic content and DPPH radical scavenging ability increased continuously to their maximum values（259.4 mg/L,90.9 %） on the 21^st day followed by a decrease.