生香酵母发酵桑葚低糖复合果酱工艺优化及风味、抗氧化活性变化分析

Optimization of fermentation conditions and analysis of volatile components and antioxidant activity of low-sugar complex mulberry jam fermented by Wickerhamomyces anomalus Z133

为改善低糖桑葚复合果酱风味,以异常威克汉姆酵母为发酵菌株,在单因素试验基础上,以模糊数学感官综合得分结合苯乙醇含量指标,采用正交试验优化复合果浆发酵条件,采用顶空固相微萃取-气相色谱-质谱联用法结合ROAV法分析发酵果酱加工过程中挥发性风味成分变化,并比较发酵果酱与非发酵果酱基本指标、有机酸、抗氧化成分及体外抗氧化活性。结果表明:生香酵母发酵复合果浆最佳条件为:接种量1×10~5CFU/ml、发酵温度28℃、发酵时间20 h、蔗糖添加量4%,所制备的发酵果酱糖度36.02%,可溶性固形物40.15%,p H3.32,感官综合评分86.82,苯乙醇含量为2.83μg/g。挥发性物质分析结果表明,真空浓缩导致风味物质成分损失,通过生香酵母发酵使复合果浆原料增加了苯乙烯、芳樟醇、苯乙醇和辛酸乙酯等香气化合物,最终发酵果酱保留了萜品烯、苯乙醇和辛酸乙酯等7种酯类香气成分,赋予果酱更加浓郁的果香和花香气味。生香酵母发酵提高了乳酸、甲酸、乙酸含量,增加了酸度,口感较非发酵果酱更加醇厚协调,改善了复合果酱风味。生香酵母发酵对样品总酚、总黄酮和VC等抗氧化成分含量及DPPH·清除能力和总还原力均无显著影响,能够保留更多花青素,并提高了果酱·OH自由基清除率。

In order to improve the flavor quality of the low-sugar mulberry jam mixed with tomato and carrot,orthogonal experiments based on single-factor test combined with fuzzy mathematics sensory evaluation were applied to optimize the fermentation conditions of complex purple by aroma-producing yeast strain Wickerhamomyces anomalus Z133. Headspace solid-phase micro-extraction coupled with gas chromatography-mass spectrometry（ HP-SPME-GC-MS） and relative odor activity value（ ROAV） method were used to detect and analyze the changes of volatile compounds of fermented jam at different processing stage. The basic quality,organic acid,antioxidant substances and antioxidant activity in vitro were also compared between fermented jam and unfermented jam. The results showed that the optimal fermentation conditions were inoculation amount 1 × 10~5 CFU/ml, fermentation temperature 28 ℃,fermentation time 20 h,sugar added with 4%. The sugar content in fermented jam product was 36. 02%,total soluble solid 40. 15%,pH3. 32,sensory score 86. 82,phenylethanol content 2. 83 μg/g. Although sous vide process decreased the volatile flavor component,the fermentation by W. anomalus Z133 produced more aroma compounds for complex purple such as ethenyl benzene,linalool,phenylethanol,octanoic acid ethyl ester. Terpinene in mulberry,phenylethanol,octanoic acid ethyl ester and other seven esters compounds produced from fermentation were detected in jam. These aroma compounds newly produced by W. anomalus Z133 enriched the fruity and flower odour of jam.The contents of lactic acid,formic acid and acetic acid were increased after the fermentation,but there were no significant changes in the contents of total phenolics,total flavonoids and VC,the DPPH· scavenging activity and total reducing power. In addition,the anthocyanin was better maintained and ·OH scavenging activity was enhanced in fermented jam.