Metagenomic analysis revealing the metabolic role of microbial communities in the free amino acid biosynthesis of Monascus rice vinegar during fermentation

Free amino acid(FAA)is the important component of vinegar that infl uences quality perception and consumer acceptance.FAA is one of the major metabolites produced by microorganisms;however,the microbial metabolic network on FAA biosynthesis remains unclear.Through metagenomic analysis,this work aimed to elucidate the roles of microbes in FAA biosynthesis during Monascus rice vinegar fermentation.Taxonomic profiles from functional analyses showed 14 dominant genera with high contributions to the metabolism pathways.The metabolic network for FAA biosynthesis was then constructed,and the microbial distribution in different metabolic pathways was illuminated.The results revealed that 5 functional genera were closely involved in FAA biosynthesis.This study illuminated the metabolic roles of microorganisms in FAA biosynthesis and provided crucial insights into the functional attributes of microbiota in vinegar fermentation.

Microbial metabolic interaction in fermentation ecosystem and cooperation in flavor compounds formation of Chinese cereal vinegar

Shanxi aged vinegar(SAV)is a famous cereal vinegar in China,which is produced through a solid-state fermentation where diverse microbes spontaneously and complex interactions occur.Here,combined with the metatranscriptomics,the microbial co-occurrence network was constructed,indicating that Lactobacillus,Acetobacter and Pediococcus are the most critical genera to maintain the fermentation stability.Based on an extensive collection of 264 relevant literatures,a transport network containing 2271 reactions between microorganisms and compounds was constructed,showing that glucose(84%of all species),fructose(67%)and maltose(67%)are the most frequently utilized substrates while lactic acid(64%),acetic acid(45%)are the most frequently occurring metabolites.Specifically,the metabolic influence of species pairs was calculated using a mathematical calculation model and the metabolic influence network was constructed.The topology properties analysis found that Lactobacillus was the key role with robust metabolic control of vinegar fermentation ecosystem and acetic acid and lactic acid were the main metabolites with feedback regulation in microbial metabolism of SAV.Furthermore,systematic coordination of positive and negative impacts was proved to be inevitable to form flavor compounds and maintain a natural microbial ecosystem.This study provides a new perspective for understanding microbial interactions in fermented food.

Effect of vinegar supplementation on patients with esophageal lesions lightly stained with Lugol’s iodine solution:Prospective single-centre trial

BACKGROUND Esophageal chromoendoscopy with iodine solution is important for detecting early esophageal cancer.The effect of routine treatment for lesions lightly stained with Lugol’s iodine solution is limited,and the addition of natural substances to a regular diet is becoming increasingly common.Vinegar has antitumor effects as reported in previous studies.AIM To evaluate whether vinegar supplementation could improve the prognosis of patients with lightly stained esophageal lesions.METHODSThis prospective single-centre trial included consecutive patients with lightly stained lesions between June 2020 and April 2022.Patients in the experimental group received increased amounts of vinegar for 6 months.The primary outcome of the study was the clinical therapeutic effect.Complications related to vinegar ingestion and adverse events were also recorded in detail.RESULTS A total of 166 patients were included in the final analysis.There was no significant difference in the baseline data between the two groups.Intention-to-treat(ITT)analysis demonstrated that the rates at which endoscopic characteristics improved were 33.72%in the experimental group and 20.00%in the conventional group(P=0.007);and the rates at which biopsy pathology improved were 19.77%and 8.75%,respectively(P=0.011).Additional vinegar consumption had a statistically protective effect on the rate at which endoscopic characteristics improved[hazard ratio(HR)_(ITT)=2.183,95%CI:1.183-4.028;HR_(per-protocol(PP))=2.307,95%CI:1.202-4.426]and biopsy pathology improved(HR_(ITT)=2.931,95%CI:1.212-7.089;HR_(PP)=3.320,95%CI:1.295-8.507).No statistically significant effect of increased vinegar consumption on preventing high-grade intraepithelial neoplasia or early cancer was observed(HR_(ITT)=0.382,95%CI:0.079-1.846;HRPP=0.382,95%CI:0.079-1.846).The subgroup analyses indicated that the overall therapeutic improvement of endoscopic characteristics and biopsy pathology seemed more obvious in older(age>60)male patients with small lesions(lesion size≤0.5 cm).Three patients in the experimental group reported acid regurgitation and heartburn.No adverse event during gastroscopy were recorded during follow-up.CONCLUSION A moderately increased ingestion of vinegar could not directly reduce the risk of esophageal cancer in the mucosa dysplasia population,but it improved the endoscopic characteristics and ameliorated the biopsy pathology to a certain extent.Further research is needed to verify the effect of nutritional intervention on precancerous esophageal lesions.

Microbiomics and metabolomics insights into the microbial regulation on the formation of flavor components in the traditional fermentation process of Chinese Hongqu aged vinegar

This study aimed to investigate microbial succession and metabolic dynamics during the traditional fermentation of Hongqu aged vinegar,and explore the core functional microbes closely related to the formation of flavor components.Microbiome analysis demonstrated that Lactobacillus,Acetobacter,Bacillus,Enterobacter,Lactococcus,Leuconostoc and Weissella were the predominant bacterial genera,while Aspergillus piperis,Aspergillus oryzae,Monascus purpureus,Candida athensensis,C.xylopsoci,Penicillium ochrosalmoneum and Simplicillium aogashimaense were the predominant fungal species.Correlation analysis revealed that Acetobacter was positively correlated with the production of tetramethylpyrazine,acetoin and acetic acid,Lactococcus showed positive correlation with the production of 2-nonanone,2-heptanone,ethyl caprylate,ethyl caprate,1-hexanol,1-octanol and 1-octen-3-ol,C.xylopsoci and C.rugosa were positively associated with the production of diethyl malonate,2,3-butanediyl diacetate,acetoin,benzaldehyde and tetramethylpyrazine.Correspondingly,non-volatile metabolites were also detected through ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry.A variety of amino acids and functional dipeptides were identified during the traditional brewing of Hongqu aged vinegar.Correlation analysis revealed that Lactobacillus was significantly associated with DL-lactate,indolelactic acid,D-(+)-3-phenyllactic acid,pimelic acid,pregabalin and 3-aminobutanoic acid.This study is useful for understanding flavor formation mechanism and developing effective strategies for the suitable strains selection to improve the flavor quality of Hongqu aged vinegar.

Inhibition of Propionibacterium acnes by refined bamboo vinegar and preparation of the slow-release system with bamboo charcoal as the carrier

Background:Acne vulgaris is one of the most common skin diseases that can significantly impact a considerable proportion of individuals over their lifetime.Objective:This study focuses on the exploration of the application potential of bamboo vinegar in cosmetics.Materials and Methods:The stock solution of bamboo vinegar is subjected to reduced-pressure distillation at different temperatures to obtain refined bamboo vinegar.Then,inhibition of Propionibacterium acnes(P.acnes)by refined bamboo vinegar is observed.Moreover,the refined bamboo vinegar is adsorbed and released with activated bamboo charcoal as the carrier.In all,this study aims to probe into the mechanism of the controlledrelease system of bamboo vinegar.Results:The results shows that the harmful substances(tar)in bamboo vinegar distilled at 70℃decreased by 94.44%,which is a more notable decrease compared with that in the stock solution.The total organic acid content in bamboo vinegar after reduced-pressure distillation is 11.840%,reaching the national standard for refined bamboo vinegar(GB/T 31734–2015).Additionally,the minimum inhibitory concentration of refined bamboo vinegar against P.acnes using the punch method is 7.90 mg/mL.This indicates that refined bamboo vinegar has the potential as a prospective raw material for formulations in anti-acne cosmetic products.Furthermore,the release rate of bamboo charcoal/bamboo vinegar in water for 15 min reaches 70.57%,which then slows down to a plateau.The slow-release behavior is agreed with the Ritger-Peppas model and is beneficial to relieve the irritation of bamboo vinegar to the skin and lengthen its bacteriostatic duration.Conclusion:The foregoing conclusions can serve as the theoretical foundation for the application of bamboo vinegar in anti-acne cosmetics.

Production of Vinegar Mango Using Acetobacter tropicalis CRSBAN-BVA1 and CRSBAN-BVK2 Isolated from Burkina Faso

Production and quality of vinegar from mango juice was evaluated using a two steps production procedure. The first step of fermentation was done using Saccharomyces cerevisae KVL013 for 7 days. The second step, an acetic fermentation was realized using two acetic acid bacteria: A. tropicalis CRSBAN-BVA1 and A. tropicalis CRSBAN-BVK2 for 21 days. Several parameters of the vinegar produced such as physico-chemical and sensory properties were determined. Microbial density during each step was monitored. Results showed that pH, alcoholic and acetic acid contents of vinegar were respectively 2.97%, 7% and 4.54% g/ml respectively by using A. tropicalis CRSBAN-BVA1 and 3.02%, 7% and 4.32% g/ml with A. tropicalis CRSBAN-BVK2. Sensory evaluation revealed that the vinegar was acceptable to the panellists. Results of microbial density showed that the maximum concentration of cell biomass produced was 4.32 × 108 and 4.25 × 108 CFU/ml respectively for CRSBAN-BVA1 and CRSBAN-BVK2.

Response Surface Methodology as an Approach for Optimization of Vinegar Fermentation Conditions Using Three Different Thermotolerant Acetic Acid Bacteria

This study aimed to investigate optimal fermentation conditions of biological acetic acid fermentation for vinegar production. Optimization was performed on 3 acetic acid bacteria strains namely VMA1, VMA7 and VMAO using Response Surface Methodology (RSM). A Box-Behnken-Design (BBD) was achieved with three different independent process parameters involving: fermentation temperature, original alcohol concentration and original acetic acid concentration and one dependent variable (acetic acid yield). The results showed that the mathematical models describe correctly the relationship between responses and factors (F values of the models (p R2 (coefficient of correlation) respectively 0.96, 0.94, 0.98, and adjusted R2 0.95, 0.92, 0.98). The maximum acidity was obtained respectively at fermentation temperatures, original alcohol concentrations and original acetic acid concentrations ranging from [37.5°C - 45°C], [16% - 20% (v/v)], [1.5% - 2% (w/v)] for VMA1, [40°C - 45°C], [14.5% - 20% (v/v)], [1.7% - 2% (w/v)] for VMA7 and [42°C - 45°C], [17% - 20% (v/v)], [1.5% - 2% (w/v)] for VMAO. The use of these acetic strains in the production of vinegar may seriously lead to a decrease or even an ablation of the costs related to the cooling of bioreactors especially in warm and hot countries, in the context of global warming.

Impacts of dietary supplementation of bamboo vinegar and charcoal powder on growth performance,intestinal morphology,and gut microflora of large-scale loach Paramisgurnus dabryanus

Although accumulating data demonstrate that dietary supplementation of bamboo vinegar and charcoal powder(BVC)can significantly strengthen the immunity and boost the growth of domestic animals,its application potency still awaits verification in commercial fish species such as the large-scale loach Paramisgurnus dabryanus.The impacts of 90-day dietary supplementation of 1%and 2%BVC on survival and growth performance of the loach,and on the intestinal morphological characteristics and gut microflora were analyzed.Our data show that the large-scale loach supplied with BVC at the experimental doses had significant higher survival rates and better growth performance(indicated by greater weight gain(1.13–1.14 times),higher specific growth rate(1.04 times),and lower feed conversion ratio(0.88–0.89 times))compared to that of the control(P<0.05).Histological examination revealed significant longer villus(3.22–5.54 times),deeper crypt(1.77–1.87 times),and thicker muscle(1.59–3.17 times)in the intestines of large-scale loach fed with BVC(P<0.05).Furthermore,we found that the gut microflora consisted of significantly fewer proportions of potential pathogenic bacterial species(Aeromonas veronii and Escherichia coli),but significantly greater proportions of beneficial microbes(Lactococus raffinolactis and Faecalibacterium prausnitzii).Therefore,dietary intake of BVC can promote intestinal tract development and optimize gut microflora,by which the survival and growth of large-scale loach may be improved.

Effects of Biochar and Wood Vinegar on Labile Phosphorus Pool in Soda Saline-Alkaline Soil

A pot experiment was conducted to research the effect of biochar and wood vinegar on labile phosphorus fractions in saline-alkali soil.There were eight treatments,including CK(0 kg•hm-2 biochar+0 kg•hm-2 wood vinegar),C1(0.6 t•hm-2 biochar),C2(0.6 t•hm-2 wood vinegar),C3(1.2 t•hm-2 wood vinegar),C4(1.8 t•hm-2 wood vinegar),C5(0.6 t•hm-2 biochar+0.6 t•hm-2 wood vinegar),C6(0.6 t•hm-2 biochar+1.2 t•hm-2 wood vinegar),and C7(0.6 t•hm-2 biochar+1.8 t•hm-2 wood vinegar).The results showed that biochar without wood vinegar and the co-application of biochar and wood vinegar significantly increased soil total phosphorus content.Meanwhile,compared with CK,all of treatments increased resin phosphorus and sodium bicarbonate-extracted inorganic phosphorus(NaHCO3-Pi)contents in saline-alkali soil.Especially,the contents of resin phosphorus and NaHCO3-Pi under C5,C6,and C7 treatments were higher than those of C2,C3,and C4 treatments,respectively,indicating that the increases of labile phosphorus contents under the co-application of biochar and wood vinegar were better than those of the alone application of biochar and wood vinegar.Each treatment increased the proportion of labile phosphorus pool in saline-alkali soil and the proportion of labile phosphorus pool increased with the increase of the amount of wood vinegar.In addition,the application of biochar and wood vinegar increased the 100-grain weight of rice,and C6 treatment had the best effect,increasing the 100-grain weight by 134.35%.Therefore,the application of biochar and wood vinegar in saline-alkali soil could improve the soil phosphorus availability,increase the weight of rice grains,thereby realizing the resource utilization of agricultural waste and the sustainable development of agriculture.

Effect of Mongolian Vinegar Soaked Licorice on Liver Fibrosis Induced by Carbon Tetrachloride Combined with High-fat Diet in Rats

[Objectives]To determine the improvement effect of vinegar soaked licorice on liver fibrosis induced by carbon tetrachloride(CCl_(4))combined with high-fat diet in rats.[Methods]Subcutaneous injection of 40%-60%CCl_(4)olive oil solution(0.3 mL/100 g)combined with a high-fat diet was used for 5 weeks to establish the rat model with liver fibrosis.After the modeling,the rats were divided into a low dose(0.8 g/kg),a medium dose(2.5 g/kg),a high dose(5 g/kg)group,a colchicine(1.5 mg/kg)positive group,and a vinegar group(2 mL/kg).The serum alanine aminotransferase(ALT)and aspartate aminotransferase(AST)levels in the rats were measured automatically.The serum hyaluronic acid(HA)was detected by radioimmunoassay,and the serum laminin(LN)and procollagen type III peptide(PIIIP)levels were measured by enzyme-linked immunoassay.Liver histopathological morphological changes were observed by HE and Masson staining,and expressions of cytochrome CYP2E1 and transcription factor Nrf2 were detected by immunohistochemistry.[Results]The rat liver fibrosis model was established successfully at the 6~(th)week.Compared with the model group,the levels of ALT,AST,HA,LA,PIIIP,CYP2E1 and Nrf2 of all the examined indexes in the dosing group were decreased(P<0.05).As shown in the pictures of liver pathological tissue sections,the liver fibrosis was significantly alleviated in the positive group and the 3 administration groups.[Conclusions]Vinegar soaked licorice can significantly improve the liver fibrosis induced by carbon tetrachloride combined with high-fat diet in rats,and the effect of the high-dose group was similar to that of the positive group.

Effects of Different Sterilization Conditions on Active Components and Flavor of Apple Vinegar

[Objectives]To explore the effects of different sterilization conditions on nutrition and flavor of apple vinegar.[Methods]Five kinds of high temperature short time(HTST)sterilization conditions were selected to treat apple vinegar,and the volatile aroma components and the content of active components in apple vinegar before and after sterilization were analyzed.[Results]Compared with the control,the contents of total acid and malic acid in the samples after sterilization changed little,but the contents of citric acid increased significantly(P<0.01),and the contents of total phenols,ascorbic acid and total flavonoids decreased.Ethyl acetate,isopentyl acetate,ethyl caprylate,phenethyl acetate,1-pentanol,phenylethyl alcohol,acetic acid,and sec-butyl ether were the characteristic aroma components which contributed to the flavor of apple vinegar.As sterilization temperature increased,the content of esters decreased,while the content of acids,alcohols and aldehydes increased.The contents of nutrition,active components and volatile aroma components in apple vinegar under 100℃and 30 s sterilization conditions had little change compared with other sterilization conditions,so 100℃and 30 s were the optimal sterilization conditions.[Conclusions]Under different sterilization conditions,the content of flavor components in apple vinegar will change greatly,which will affect the quality of apple vinegar.

食用醋粉的制备工艺、营养成分及保健作用研究进展

综述了食用醋粉的制备工艺、营养成分和保健作用,并对其未来发展进行了展望,以期为食用醋粉的综合利用提供参考。

醋醅源非酿酒酵母的鉴定及其对葡萄酒品质的影响

为改善传统商业酿酒酵母酿造葡萄酒的风味与口感,以醋醅中分离的菌株JM为研究对象,对其进行形态学观察、分子生物学鉴定和耐受性分析;以菌株JM、商业酿酒酵母(SC)和安琪活性生香干酵母(ADY)单菌及混菌发酵酿造葡萄酒,并对其品质进行分析。结果表明,经鉴定,菌株JM被鉴定为扁平云假丝酵母(Candida humilis),在发酵液中总酯产量为2.64 g/L,其可耐受3.0%柠檬酸、温度35℃、体积分数6%的乙醇及4%NaCl。在不同组别葡萄酒样品中,JM+SC混菌制备的葡萄酒品质最佳,其酒体颜色为紫红色,L*值、a*值、b*值分别为53.93、20.38、4.85;糖度为7°Bx,总酸含量为3.38 g/L,还原糖含量为22.00 g/L,pH为3.58,花色苷含量为205.52 mg/L,酒精度为12.60%vol,总酯含量为1.47 g/L;1,1-二苯基-2-三硝基苯肼(DPPH)、2,2'-联氮-双(3-乙基苯并噻唑啉-6-磺酸)(ABTS)自由基清除率分别为42.21%、32.86%;酒样富含丙酸乙酯和乙酸戊酯,果香浓郁,清爽可口,具备酿造高品质葡萄酒的潜力。

甘草柑橘皮果醋发酵工艺研究

以柑橘皮为主料,甘草为辅料,采用液态发酵法制备甘草柑橘皮果醋。先以总黄酮含量为指标,在单因素试验的基础上通过响应面法优化酒精液制备工艺;再在最佳酒精液制备条件下,以总酸含量和感官评分为指标,通过响应面法优化果醋制备工艺,并对其理化及微生物指标进行分析。结果表明:酒精液最佳工艺参数为酵母菌接种量0.5%(以原料液体积为基准)、原料液糖度16%、发酵时间9 d,在此条件下果醋总黄酮含量为5.37%。最佳果醋制备参数为醋酸菌接种量2.0%(以酒精液体积为基准)、发酵温度35℃、初始乙醇体积分数8.5%、发酵时间9 d,在此条件下果醋总酸含量为5.61 g/100 mL,感官评分为8.74,微生物指标符合相关标准要求。

不同醋酸菌对菠萝糯米果粮醋风味的影响

为探究不同醋酸菌对菠萝糯米果粮醋醋酸发酵过程和风味的影响,该研究分析了醋酸发酵过程中菌落总数、温度、总酸、不挥发酸的变化和醋液有机酸含量与挥发性成分。结果表明,与沪酿1.01相比,醋酸菌DHC23能更快适应高乙醇环境,同时能耐受更高的温度;上醅醋酸菌DHC23菌落总数峰值为1.52×10^(8)CFU/g,而沪酿1.01仅为1.95×10^(7)CFU/g;由于翻醅,醅温呈现周期性升降变化,前者峰值为42.1℃,后者仅为40.2℃。两组醋醅总酸含量均逐渐增加,不挥发酸含量均先上升后缓慢下降,而醋酸菌DHC23更有利于总酸和不挥发酸含量的提升,且使发酵时间缩短1 d。DHC23组醋液中乙酸、乳酸、柠檬酸、琥珀酸、酒石酸和焦谷氨酸含量均比沪酿1.01组含量高,且差异显著。两组醋液挥发性成分种类差异不显著,但醋酸菌DHC23有利于醛类、酸类、酯类和吡嗪类物质的生成。

基于小白鼠试验评价乳清醋增强免疫功能研究

用乳清醋饲喂小白鼠试验,分析检验其免疫学指标,评价乳清醋是否具有增强机体免疫的功能特性。试验鼠选用体质量(BW)为20 g的雄性小白鼠,共320只,从中每次随机取40只作为1个批次饲喂的试验鼠,分为4组,3个处理组和1个对照组,每组10只。实验室制备总酸为5.52 g/100 mL的乳清醋,乳清醋经稀释后的高、中、低浓度的剂量组,分别对处理组小鼠以剂量为10 mL/kg BW灌胃,对照组同步灌胃等量生理盐水,日饲1次,连续30 d为1个批次饲喂试验。研究以试验鼠的8项免疫学指标为检测目标:(a)免疫器官重量及胸腺脾脏指数,(b)迟发型超敏反应,(c)淋巴细胞转化率,(d)抗体生成细胞检测,(e)血清溶血素检测,(f)单核巨噬细胞攻击和吞噬能力,(g)碳粒廓清试验,(h)NK(Natural killer)细胞活性。每一批次饲喂试验结束后,针对其中1项免疫学指标要求对该批次的小鼠进行处置、解剖、检测。取平均数据为该批次各组鼠的该项免疫学指标数据。经8批次的饲喂试验,完成了试验鼠8项免疫学指标的检测。结果显示,处理组与对照组相比,除了(d)和(e)2项指标没有明显的统计学差异(P>0.05)外,中、高剂量组小鼠的其余6项免疫学指标均明显增强,均有统计学差异(P<0.05)。本研究发现,乳清醋饲喂白鼠后在促进和提高小鼠的免疫器官增重,细胞免疫功能,单核巨噬细胞吞噬功能和NK细胞活性等方面起了明显作用,可以判定乳清醋具有增强人体免疫力的功能。

发酵型茶醋的品质分析及抑菌性

以广西贺州生产的红茶(迎霜、月湾)、绿茶(开山白毛、茗山)为原料,分别与新鲜甘蔗汁混合发酵制备茶醋,考察其醋酸发酵过程中的色差、总酸、茶多酚、茶氨酸、总黄酮等指标变化,并通过电子鼻测定茶醋整体特征气味轮廓,同时采用牛津杯‐琼脂法分析4种茶醋对大肠埃希氏菌、金黄色葡萄球菌、白色念珠菌3种致病菌的抑菌效果。结果显示,绿茶(开山白毛、茗山)发酵体系的产酸能力较强,且茶多酚含量较高,茶醋中总黄酮成分保留较好;酸类、醇类、芳香化合物、烷类物质是茶醋的整体特征气味轮廓;以抑菌圈的大小判断4种茶醋的抑菌效果发现4种茶醋对大肠埃希氏菌、金黄色葡萄球菌、白色念珠菌都有一定的抑菌效果,抑菌圈明显,且茗山茶醋抑菌效果最佳,其对3种致病菌的抑菌作用为高敏感。不同茶叶品种发酵的茶醋品质和抑菌效果都有明显差别,但绿茶发酵的茶醋的口感比红茶发酵的茶醋丰富,且茶香、醋香味较为明显。

不同酸化生物炭用量对滴灌棉田盐碱土水盐运移的影响

【目的】研究不同酸化生物炭用量对滴灌棉田盐碱土水盐运移的影响,确定改良棉田盐碱土的最佳木醋液酸化生物炭用量。【方法】基于一维土柱模拟试验,分别设置1%、2%、3%、4%和5%五个不同质量木醋液酸化生物炭处理(木醋液与生物炭质量比为2∶1),以空白处理作为对照CK_(1),以添加2%未酸化生物炭处理作为对照CK_(2),分析不同处理滴灌后湿润峰垂直运移距离、土壤pH值、含盐量、土壤碱化度和脱盐率的分布特征。【结果】添加酸化生物炭处理的土壤湿润峰垂直运移距离和下渗速度均显著高于CK_(2)和CK_(1);添加酸化生物炭处理下的各层土壤pH值均显著低于CK_(2)和CK_(1),且施用量越多pH值降幅越大;随着酸化生物炭施用量的增加,各土层土壤碱化度呈先降低后升高的变化趋势,2%酸化生物炭处理下的土壤碱化度降幅最大;添加未酸化生物炭和酸化生物炭处理的0~50 cm各层土壤脱盐率均有所增加,2%酸化生物炭处理下的整体脱盐效果最好。【结论】添加酸化生物炭对盐碱土的改良效果优于添加未酸化生物炭,以2%酸化生物炭用量下的效果最优。

添加部分水解罗望子胶对酸木瓜果醋品质的影响

该研究以酸木瓜(Chaenomeles speciosa)为原料,通过部分水解罗望子胶(PHTG)对6株乳杆菌的增殖活性测定,选用鼠李糖乳杆菌(Lactobacillus rhamnosus)与酵母菌混菌进行酒精发酵,并从灵石醋醅中筛选鉴定出一株高产醋酸的巴氏醋杆菌巴士亚种(Acetobacter pasteuranus subsp. pasteuranus)LS-4用于醋酸发酵制备酸木瓜果醋。以未添加PHTG为对照,考察在酒精发酵阶段添加PHTG对酸木瓜果醋品质的影响。结果表明,添加1.0%PHTG,酒精发酵36 h后酒精度达3.3%vol,比对照组提高17.4%;醋酸发酵72 h后总酸含量达42.0 g/L,比对照组提高8.0%。香气成分分析表明,添加PHTG酸木瓜果醋共检出22种香气成分,其中醇类7种、酯类4种、酸类6种、醛酮类3种、酚类和烯烃类各1种,比对照新增了3种香气成分(正丁酸、2-戊酮和壬醛)。感官评价表明,添加PHTG有效提升酸木瓜果醋的口感和气味评分,改善酸木瓜果醋的感官品质。

唾液对山西老陈醋香气释放的影响

为研究只含粘蛋白的人工唾液和离体的人唾液对山西老陈醋香气释放的影响,采用顶空固相微萃取(HS-SPME)结合全二维气相色谱-飞行时间-质谱(GC×GC-TOF-MS)联用技术对3种山西老陈醋中挥发性香气成分进行分析。通过聚类分析(CA)比较唾液对3种山西老陈醋挥发性化合物含量的影响,并利用香气活性值(OAV)筛选出山西老陈醋的关键风味物质,通过绘制山西老陈醋的香气轮将香气化合物的含量数据转化为感官描述信息,明确唾液对山西老陈醋感官特征的影响。结果表明,从山西老陈醋中共检出105种挥发性化合物,在2种类型唾液的影响下,65种挥发性化合物的含量均显著降低(P<0.05),特别是酯类和酮类,OAV>1的27种关键香气化合物中将近一半化合物的OAV均减少了10%以上,说明唾液会影响山西老陈醋的感官特征。2种类型的唾液均会减弱山西老陈醋香气化合物的感官属性,尤其是对坚果味、奶香味和花香味。该研究明确了唾液对山西老陈醋的香气释放有影响,为提升山西老陈醋的感官体验提供了理论依据。