Optimization of Acetic Acid Fermentation Process of Apple Cider Vinegar

This paper studied the fermentation rules of apple cider vinegar from fruit juice,to provide a theoretical guidance for the production of apple cider vinegar.Using Fuji apples as raw materials,the process parameters(fermentation temperature,fermentation time,stirring speed,and inoculation amount)of apple cider vinegar fermentation were optimized through single-factor experiments and response surface analysis.The results indicated that the fermentation temperature had no significant effect on the total acid content of apple cider vinegar fermentation,the fermentation time had an extremely significant effect on the total acid content of apple cider vinegar fermentation,and the stirring speed and inoculation amount had a significant effect on the total acid content of apple cider vinegar fermentation.Through process optimization,the optimal process parameters for apple cider vinegar fermentation are fermentation temperature of 33℃,fermentation time of 39 h,stirring speed of 1500 r/min,and acetic acid bacteria inoculation amount of 7%.Under such conditions,the total acid content of fermented apple cider vinegar is 62.22 g/L,very close to the predicted value of the model,indicating that the process parameters of acetic acid fermentation obtained by response surface methodology(RSM)optimization are reliable and can be used for actual production prediction.

Isolation of Acetic Acid Bacteria and Preparation of Starter Culture for Apple Cider Vinegar Fermentation

Vinegars are commonly used as food condiments and preservatives. Apple cider vinegar (ACV) is also used in the Ayurvedic pharmaceutical industry because of its medicinal properties. Since specifically selected starter cultures for commercial vinegar production are not readily available, apple juice supplemented with sugar is commonly inoculated with a microbiologically undefined culture obtained from the previous batch of ACV. The present work focuses on the isolation of yeasts and acetic acid bacteria from ACV and the preparation of a starter culture. ACV was produced in a bench scale bioreactor using a traditional fermentation process wherein an acetic acid concentration of 3.8% was obtained after three weeks. Several acetic acid bacteria (AAB) were isolated from ACV using selective media. Microscopy revealed the cultures to be gram negative to gram variable short rods. The growth pattern of the isolates on differential media and biochemical tests suggested the presence of Acetobacter and Gluconobacter species. Ten potent isolates were selected for starter culture preparation. Two consortia were formulated with five AAB isolates in each along with a yeast isolate and used for ACV production, wherein an acetic acid concentration of 4.2% - 4.9% was obtained in 10 - 12 days. Thus, these two starter cultures with locally isolated AAB can be used for the commercial production of apple cider vinegar.

Lipid Peroxidation and Some Antioxidant Enzymes Evaluation in Apple Cider Vinegar (ACV) Treated Male and Female Wistar Rats Exposed to Chronic Restraint Stress

This study was designed to assess the effect to apple cider vinegar (ACV) on oxidative stress biomarkers in male and female Wistar rats exposed to chronic restraint stress. Severe and persistent stress elevates reactive oxygen species (ROS) production by metabolic and physiological processes;causing cellular damage. Thirty (30) Adult Wistar rats of both sexes weighing about 150 - 200 g were divided into 3 groups each consisting of a male and female subgroup and given the following treatments once a day for 21 days: Normal control group received 0.5 ml distilled water orally, the restraint stress (RS) group was exposed to chronic restraint stress 6 hours daily while the Apple cider vinegar (ACV)-treated group received 4 ml/kg of apple cider vinegar orally in addition to chronic restraint stress 6 hours daily. The rats were sacrificed after the experimental period and blood was collected via cardiac puncture for assessing oxidative stress biomarkers. ACV (4 ml/kg) treatment decreased lipid peroxidation (MDA) and serum catalase (CAT) activity while upregulating endogenous superoxide dismutase (SOD) activity. The findings of this study show that the female Wistar rats are more predisposed to the antioxidant effect of ACV than the males.

Prevalence and Disinfection of Bacteria Associated with Various Types of Wristbands

The potential role of personal items in the transmission of pathogens is poorly understood. In this study, we cultured bacteria of public health importance found on wristbands, determined whether there is a correlation between wristband material and prevalence, and tested three household disinfectants for efficacy in reducing bacteria on wristbands made of plastic, rubber, metal, and cloth, using standard microbiological assays. Total cultivable bacteria, Staphylococci, Enterobacteria (Escherichia coli), and Pseudomonas on 20 smartwatch wristbands were cultured from randomly recruited subjects. Nearly all wristbands (95%) were contaminated, with the highest average numbers of 3.46E+4 cfu/cm2 and 1.52E+4 cfu/cm2 on rubber and plastic bands respectively. Metallic gold and silver wristbands had zero to 18 cfu/cm2. While the high prevalence of Staphylococcus spp (85% of wristbands)—skin microbiota;was not unexpected, the occurrence of Pseudomonas spp (30%), and enteric bacteria (60%), even at relatively low numbers is of public health significance. Bacterial load on individual subjects varied remarkably with males and females harboring average total bacteria of 4.045 and 3.42 log10cfu/cm2 of wristband, respectively. The most important predictor of wristband bacteria load was the texture of wristband material and activity (hygiene) of the subject at sampling time. Potential pathogens—Staphylococcus aureus (8143 cfu/cm2) and Pseudomonas spp. (1126 cfu/cm2) were most abundant on cloth and rubber wristbands, respectively, while the presence of the E. coli group was associated with animal handling activity by a veterinarian. Lysol Disinfectant Spray and 70% Ethanol were highly effective regardless of wristband material with >99.99% kill rate and a log cfu/cm2 reduction of 3 - 4.0 and 3 - 4.5 respectively within 30 seconds. Apple Cider Vinegar (ACV) was not as potent. Only 2 - 3.5 log cfu/cm2 drop was obtained after 120 seconds of exposure. Further susceptibility assays with standard reference bacteria showed that Lysol and 70% alcohol effectively killed > 99.99% (>8 log CFU drop) of Escherichia coli strain 7001, Staphylococcus aureus strain 6538, and Pseudomonas aeruginosa strain 10662 within 30 seconds of contact. Vinegar had a similar efficacy on the gram negatives but little or no effect on Staph aureus (only a 2-log CFU/ml reduction in 5 minutes!) The high prevalence of potential pathogens, some of which could be reservoirs of antibiotic resistance reveals a weak link in infection control and underscores the need for regular cleaning of personal and hand-held accessories with adequate considerations of their texture.

不同来源的苹果醋理化指标、抗氧化活性和风味特性分析

为了比较不同来源的苹果醋产品的差异,该研究对国内外的19个苹果醋产品的理化指标、抗氧化活性和风味特性进行测定与对比分析。结果显示,在参试苹果醋样品中,国外样品总酸含量(6.3 g/100 mL)较高、氨基酸含量(83.8 mg/L)较低,国内样品还原糖含量(5.3 g/L)和氨基酸(160.2 mg/L)含量较高;国外样品的FRAP抗氧化活性(0.8 mmol Trolox/L)较高,国内样品ABTS自由基清除率(56%)较高,DPPH自由基清除率差异不显著;浊汁样品的ABTS、DPPH自由基清除率和FRAP值皆极显著高于清汁样品(P<0.01),但氨基酸总含量(30.3 mg/L)显著低于清汁样品(182.6 mg/L)(P<0.05);国内外及清浊汁样品的有机酸总含量(20~40 g/L)及组成差异不大,且挥发性物质总含量基本相似,其中乙酸、异戊酸、乙酸乙酯、乙酸异戊酯和苯乙醇等挥发性物质是苹果醋重要的风味物质;由相关性分析结果可知,总多酚和总黄酮含量与苹果醋的抗氧化活性呈正相关。综上,参试的不同来源苹果醋样品主要在理化、抗氧化活性指标上存在较显著的差异。

三种食醋中酚类物质及抗氧化能力的比较研究

通过光谱和高效液相色谱技术对苹果醋、山西老陈醋及恒顺香醋中酚类物质以及抗氧化能力进行分析研究,评价三种醋的营养价值。结果表明:三种醋都具有较高的总酚,且粮食醋大于苹果醋。同时总酚与抗氧化能力呈显著正相关。在色谱条件下,以没食子酸等十六种单体酚作为标准品,苹果醋中能被定量的单体酚有8种,其中绿原酸(6.56mg/L)、咖啡酸(3.03mg/L)和根皮苷(1.76mg/L)含量最为丰富,是苹果醋相对粮食醋的特征单体酚;粮食醋(山西老陈醋和镇江香醋)中能被定量的单体酚有5种,其中没食子酸含量最高(在山西老陈醋中含量为60.56mg/L,恒顺香醋中为241.96mg/L),山西老陈醋和恒顺香醋中多酚物质结构比例差距较大。

苹果醋的开发与研究综述

回顾了苹果醋的历史和现状,对苹果醋的功能、发酵机理、风味、酿造工艺、种类和研究现状进行总结,对苹果醋的发展意义和趋势进行了讨论,并展望了苹果醋的发展前景。充分利用苹果资源进行果醋产品的开发与生产,可为苹果的深加工及综合利用创造有效途径。

虫草多糖苹果果醋的保健功能评价

目的:虫草多糖与果醋均具有对人体有益的功效,该实验将两者结合,并通过小鼠连续灌胃体内实验,考察虫草多糖果醋抗疲劳、增加免疫力、降血脂和降血糖等方面的功效。方法:首先从蛹虫草子实体中提取虫草多糖。然后以苹果为原料经过酒精发酵和醋酸发酵制备苹果果醋原液,经调配制备苹果果醋。按实验设计添加不同剂量的虫草多糖制备虫草多糖果醋。对成年小鼠进行不同剂量的虫草多糖果醋灌胃后,通过小鼠的负重游泳时间、肝糖原含量和游泳后血乳酸含量测定等判定虫草多糖果醋提高小鼠抗疲劳能力的效果。通过抑制迟发型变态反应和增强碳廓清能力测定判定虫草多糖果醋提高小鼠免疫能力的效果。对成年小鼠在饲喂高脂饲料的同时进行不同剂量的虫草多糖果醋灌胃后,通过血清总胆固醇和甘油三酯水平测定判定虫草多糖果醋对高血脂的预防效果。对成年小鼠高血糖模型进行不同剂量的虫草多糖果醋灌胃后,通过测定血糖值判定虫草多糖果醋的降血糖效果。结果:通过抗疲劳实验研究发现,虫草多糖果醋组与空白对照组相比小鼠的负重游泳时间显著提高,肝糖原含量显著升高,游泳后血乳酸含量显著降低。通过增强免疫力实验研究发现,虫草多糖果醋组与空白对照组相比,耳肿胀度明显下降,廓清指数和吞噬指数显著提高。通过辅助降血脂实验发现,虫草多糖果醋组与饲喂高脂饲料的空白对照组相比,血清总胆固醇和甘油三酯水平显著降低,小鼠体质量显著低于空白对照。通过辅助降血糖实验发现,虫草多糖果醋组与空白对照组相比,血糖水平显著降低。并且各种生物活性实验结果均与虫草多糖果醋中虫草多糖的剂量成正比。虫草多糖果醋的功效要好于虫草多糖和果醋单独使用的功效。结论:虫草多糖果醋具有缓解体力疲劳、增强免疫力、辅助降血脂和辅助降血糖的保健功能。

近红外光谱技术结合遗传算法用于苹果醋总酸定量分析

利用近红外光谱法对苹果醋中的总酸含量进行定量分析,通过PLS法建立苹果醋总酸定量分析模型,同时采用间隔偏最小二乘法(i PLS)、后向间隔偏最小二乘法(Bi PLS)和组合间隔偏最小二乘法(Si PLS)以及遗传偏最小二乘法(GA-PLS)对整个谱区进行光谱特征波段筛选。用决定系数(R2)、校正标准偏差(RMSEC)、预测标准偏差(RMSEP)以及最佳主因子数对模型进行评价,确定最佳建模方法。结果表明:进行特征波段筛选能够对模型起到优化作用,并提高模型运算速度,其中GA-Bi PLS及GA-Si PLS优化效果最为明显,在极大减少苹果醋总酸建模变量的同时,模型的R2分别达到0.989和0.986,RMSEP分别为0.042和0.044,有效地提高了模型的稳定性与准确度,表明了遗传算法在果醋品质分析方面的巨大潜力。

苹果醋清除DPPH自由基活性成分的研究

以苹果、酵母菌和醋酸菌为试验材料,采用不同的发酵工艺,对4种苹果醋样品进行抗氧化活性成分分析和DPPH自由基清除率的测定,研究其主要活性成分含量与DPPH自由基清除率之间的相关性.结果表明:苹果醋具有较高的抗氧化活性成分和较强的抗氧化能力,其中固态发酵苹果醋中总酚、总黄酮含量分别达到2.14、2.19mg/mL;当加入质量浓度200μg/mL苹果醋时,DPPH自由基清除率达92.37%,总酚、总黄酮含量和DPPH自由基清除率之间有较高的相关性,相关系数分别为0.875 8、0.872 3.

我国苹果醋产业现状、存在问题及发展趋势

介绍了国内外苹果醋企业发展、市场需求、加工技术装备、工艺水平、主要研究内容、标准体系与质量控制状况等方面的发展现状,分析了目前我国苹果醋产业发展中存在的问题,并进一步指出我国苹果醋产业发展的趋势。

苹果玫瑰复合果醋饮料配方优化及营养成分测定

为开发苹果玫瑰复合果醋饮料新产品,采用L9(34)正交实验进行配方优化,对优化配方产品进行理化指标、微生物指标及氨基酸、单体酚、矿物质等营养成分测定分析。结果显示:苹果玫瑰复合果醋饮料的最佳调配比例为:饮料用苹果醋8 mL/100 mL,玫瑰提取液20 mL/100 mL,蔗糖5 g/100 mL,浓缩苹果汁3 g/100 mL。产品理化指标、微生物指标符合国家标准要求。与单一苹果醋饮料相比,复合果醋饮料中含氨基酸16种,总量达到441.47μg/mL,必需氨基酸总量为273.35μg/mL,占总氨基酸含量的61.92%;单体酚总含量达266.97μg/mL,物质浓度提高164倍。此结论可为复合果醋的开发研究提供理论依据。

苹果酒、醋中香气物质分析

采用GC-MS法对'95-54'、'95-117'苹果酒、醋中的香气物质的种类与含量进行检测分析。95-54苹果酒中检测出48种香气物质,占总峰面积的90.36%。95-54苹果醋中检测出42种香气物质,占总峰面积的98.66%。95-117苹果酒中检测出43种香气类物质,占总峰面积的86.59%。95-117苹果醋中检测出49种香气物质,占总峰面积的99.37%。这些香气物质主要是醇类、醛类、酮类、酸类、酯类、缩醛类和萜烯类。分析得出不同品种的苹果酒和苹果醋都存在一定的共性和差异,苹果酒和醋之间的香气差异也均符合酒醋基本特征。

苹果醋中有机酸成分的GC-MS分析

文章以陈醋作对照分析,采用气相色谱-质谱联用(GC-MS)对苹果醋中的有机酸含量进行了分析测试。实验数据显示,苹果醋含有特殊的有机酸,具有较高的营养保健功效。

酶在苹果醋澄清中的应用研究

研究了用酶-明胶-硅溶胶澄清法对苹果醋进行澄清。结果显示:先用淀粉酶150 mg/L、果胶酶1000 mg/L在55℃处理150min,再在该苹果醋中加明胶6 mg/L,硅溶胶65 mg/L,澄清60min,澄清度超过93%。

局部块冰式两级冷冻浓缩制备高浓度苹果醋

采用自主研发50 L渐进式局部块冰冷冻浓缩中试设备浓缩可溶性固形物含量为5.0°Brix的苹果醋,通过调节搅拌速度和冷媒温度,综合能耗、时间等因素,探究两级浓缩最佳工艺条件并对其夹带进行有效回收,同时采用固相微萃取-气相色谱质谱联用技术研究苹果原醋、各级浓缩复原液、两级夹带液、夹带回收液及终极夹带的芳香物质变化。结果表明,50 kg 5.0°Brix的苹果醋在-10℃静置冻结3 h再转入-16℃,搅拌速度900 r/min,21 h可得12.5°Brix的浓缩液14.74 kg;50 kg 12.5°Brix的果醋-16℃保持4 h后转入-24℃,900 r/min,28 h可得25°Brix浓缩液15.11 kg,两级浓缩耗电量分别为72,135 kW·h。经测定,苹果醋中芳香物质有14种,含量较高的特征组分有苯甲醛、辛酸、4-乙苯酸-2-丁基酯、苯乙醇、乙酸苯乙酯等,经一级浓缩后芳香物质保留率为80.23%,二级浓缩保留率为87.73%,苹果醋最终经两级浓缩复原后芳香物质保留率可达70.39%,总损失率为2.61%。因此通过两级浓缩,同时对夹带回收循环利用,可得到浓度较高及芳香物质保留较高的苹果醋。

一种配制型块菌苹果醋的研制

以苹果和块菌为原料,采用发酵法酿制苹果醋和乙醇溶液浸提法制取块菌提取液,并通过酒精计法、斐林试剂法和酸碱滴定法分析发酵过程中酒精含量、糖度及酸度的变化,再通过正交试验优化块菌苹果醋饮料的调配比例。通过采用气相色谱对块菌中α-雄烷醇进行定量分析,对最优调配比例的块菌苹果醋中的氨基酸和挥发性风味成分进行分析。结果表明:酒精发酵阶段随发酵时间的延长,苹果汁的糖度呈不断降低的趋势,酒精含量则不断升高,但发酵至6 d后均无显著变化(p>0.05);醋酸发酵阶段随发酵时间的延长,酒精含量逐渐降低,酸度快速增加,且发酵至5天后均无显著变化(p>0.05);块菌苹果醋饮料最佳的调配比例为蔗糖7 g、块菌提取液11 mL、苹果原醋34 m L。块菌中α-雄烷醇及其同分异构体的含量分别为0.019 2μg/100 g和0.707μg/100 g;块菌苹果醋中一共检测出了12种氨基酸(含量为288.43 mg/100 mL),其中包含6种必需氨基酸(含量为32.41 mg/100 m L);此外,还检测出了24种风味物质,其中包含15种酯类。

苹果醋中多酚及黄酮含量分析

文章以半成熟苹果为原料制成苹果醋,并对苹果醋中多酚及黄酮类物质进行含量分析,多酚含量达到58.10 mg/dL,黄酮含量达到56.80 mg/dL。

5种澄清剂对半固态发酵苹果醋的澄清效果

采用5种澄清剂对苹果醋进行澄清试验,结果表明,各澄清剂对苹果醋的澄清均有一定效果,琼脂和2种复合澄清剂效果接近,但经琼脂和复合澄清剂处理过的苹果醋有少量悬浮物。硅藻土和明胶的澄清效果均较好,但明胶对苹果醋的风味有一定影响。根据对比和感官评定,确定的最佳澄清剂为硅藻土,添加质量浓度为0.4g/L,处理时间为24 h,处理后的苹果醋上清液澄清透亮,透光率达到96.62%,分界面明显,无悬浮物,口感良好、口味协调。

甜味剂对苹果醋饮料感官质量的影响

苹果醋饮料在调配过程中往往需要加入甜味剂,常见的甜味剂蔗糖、蜂蜜、果葡糖浆、阿斯巴甜等,而蔗糖、蜂蜜在酸性条件下易产生絮凝物,影响产品感官质量。在苹果醋饮料基础配方研究基础上,采用果葡糖浆部分替代蔗糖、蜂蜜,进行复合甜味剂的协同增效研究,经正交试验优化得出苹果醋饮料复合甜味剂的较优配比为:果葡糖浆15 g/kg、蔗糖20 g/kg、三氯蔗糖0.15 g/kg(限量0.25 g/kg)、阿斯巴甜0.40 g/kg(限量0.60 g/kg),质量比为0.75∶1∶0.0075∶0.02。以此配方配制的苹果醋饮料经过滤、杀菌,常温放置150 d后絮凝物含量减少了0.95 g/L,饮料透光率达98%。