混菌发酵对无盐酸菜品质特性的影响

目的:利用乳酸菌发酵无盐酸菜。方法:通过考量菌株的发酵特性和抑菌能力,筛选具有高产酸能力和抑菌能力的乳酸菌制成混合发酵剂,并对其发酵工艺进行优化。结果:植物乳杆菌和嗜酸乳杆菌的生长活性、产酸能力及抑菌能力较强,选二者为发酵菌株;最佳发酵工艺条件为m_{植物乳杆菌}∶m_{嗜酸乳杆菌}为2∶1,250 g白菜中乳酸菌接种量为450μL,玉米汁添加量为7.5 g,发酵温度30℃,此条件下制备的酸菜颜色和气味较好,感官品质最佳。结论:在无盐条件下,接种乳酸菌发酵酸菜是控制发酵过程、优化产品质量的有效手段,可以确保发酵稳定进行并获得高品质酸菜。     

响应面法优化金银花枸杞风味酸奶的发酵工艺

以金银花、枸杞、全脂奶粉为原料,采用单因素试验研究了金银花汁添加量、枸杞汁添加量、白砂糖添加量、发酵温度、发酵时间、发酵剂接种量对金银花枸杞风味酸奶发酵的影响。以感官评分为响应值,采用响应面法对金银花枸杞风味酸奶的发酵工艺条件进行优化。结果表明,金银花枸杞风味酸奶的最佳发酵工艺条件为金银花汁添加量5%、枸杞汁添加量6%、白砂糖添加量8%,发酵剂接种量10%,发酵温度43 ℃,发酵时间5.1 h。在此优化工艺条件下,发酵的金银花枸杞风味酸奶组织细腻,酸甜可口,具有独特的中药香,感官评分为91分。     

花生芽鹰嘴豆复合酸奶的发酵工艺优化

以奶粉、花生芽和鹰嘴豆为主要原料,安琪12菌型酸奶发酵剂为发酵菌种,制备花生芽鹰嘴豆复合酸奶。以酸度、黏度、乳酸菌数、感官评分为评价指标,研究糖添加量、接种量、发酵温度和发酵时间对花生芽鹰嘴豆复合酸奶发酵的影响,并采用正交试验优化其发酵条件。结果表明,各因素对酸奶感官评分的影响顺序依次为接种量＞糖添加量＞发酵温度＞发酵时间;各因素对乳酸菌数的影响依次为接种量、发酵时间、发酵温度、糖添加量。花生芽鹰嘴豆复合酸奶最佳发酵工艺条件为接种量5 g/L,白砂糖添加量8%,发酵温度39 ℃,发酵时间24 h。此优化条件下获得的酸奶风味良好,乳酸菌数为8.11×108 CFU/mL,感官评分为92分,酸度为78.31 °T。     

添加白酒对人工接种东北酸菜挥发性风味成分及感官特性的影响

该实验研究了添加白酒对人工接种乳酸菌发酵东北酸菜理化、挥发性风味成分及感官特性的影响。首先通过乙醇胁迫及产酸能力测定筛选混菌发酵剂,采用顶空固相微萃取（HS-SPME）结合气相色谱-质谱联用（GC-MS）分析酸菜的挥发性风味成分,并结合感官评分与电子舌鉴定白酒对酸菜感官特性的影响。结果表明,植物乳杆菌（Lactobacillus plantarum）、干酪乳杆菌（Lactobacillus casei）和柠檬明串珠菌（Leuconostoc citreum）3株乳酸菌对乙醇具有一定耐受性且产酸能力较强。添加2%白酒结合3株乳酸菌混菌发酵酸菜的可滴定酸含量较未添加白酒的混菌发酵酸菜降低了4.02%。此外,添加白酒接种发酵酸菜形成了以酯类、酮类、含硫化合物和氨基酸为主的风味结构,并且提高了鲜味,降低了苦涩味,在颜色、味道和口感上均具有显著优势。为实现人工接种东北酸菜的品质提升提供理论基础。     

适于南瓜汁原料益生酵母菌的分离鉴定及发酵工艺优化

本实验以密本南瓜(Cucurbita moschata Duch.)为发酵原料,以山西代县传统发酵酱菜中筛选所得菌株为发酵菌株。采用平皿培养及感官评价相结合的方法筛选出一株能发酵南瓜汁的酵母菌,并对其进行18S rDNA鉴定,采用邻接法(NJ)构建系统发育树,鉴定该酵母为汉逊德巴利酵母(Debaryomyces hansenii)。通过模拟人工胃肠液条件测定菌株耐受性,发现该菌株耐受性较好,菌株存活率可达78.48%。通过单因素及Box-Behnken试验相结合的方法优化发酵工艺,发现接菌量、南瓜浓度、加糖量和发酵时间对工艺优化影响较大;最优工艺为接菌量15.0%,加糖量7.7%,发酵时间58 h,南瓜浓度39.0%,发酵温度32℃,110℃灭菌20 min,验证结果感官评分为91.68,与预测值相差0.37%。酵母菌株的筛选及发酵工艺的优化为发酵南瓜汁的研发应用提供理论依据。     

传统东北酸菜中优良发酵性能乳酸菌的筛选及应用

以传统东北酸菜为研究对象,从中分离筛选高产酸乳酸菌,通过探究乳酸菌的低温生长性能、耐盐特性及抑菌能力,从中获得优良发酵性能的乳酸菌,其经分子生物学鉴定后应用于发酵酸菜。结果表明,从传统东北酸菜分离筛选获得192株乳酸菌,其中5株为高产酸乳酸菌,均被鉴定为植物乳杆菌（Lactobacillus plantarum）;5株高产酸乳酸菌中植物乳杆菌DBC3和DBC33兼有多种优良性能,且在15 ℃条件下,接种量为3%的植物乳杆菌DBC33发酵得到的酸菜感官评分最高,显著缩短了发酵周期（P＜0.05）,为东北酸菜的标准化生产和酸菜发酵剂的制备提供了参考依据。     

发酵工艺对杂粮红枣发酵饼干品质的影响

以燕麦、荞麦、玉米、小米、红枣颗粒为原料,以乳酸菌和酵母菌为发酵剂,制作了杂粮红枣发酵饼干,研究了发酵工艺对饼干品质的影响。通过pH、感官评分和质构指标,分别确立了乳酸菌前发酵阶段最佳发酵工艺为:发酵时间12 h,发酵温度35℃,乳酸菌添加量1.2%;混合发酵阶段最佳发酵工艺为:酵母菌添加量2.5%、混合发酵温度32℃、混合发酵时间2.5 h、酸面团添加量25%、红枣颗粒添加量25%。在此发酵工艺下制得的饼干口感细腻、酸甜适口、质地松软、发酵风味突出、枣香味浓郁,具有良好的感官品质。     

紫薯及玫瑰花复合酸菜发酵工艺研究

采用青菜为主要原料,紫薯、酒精、玫瑰花及辣椒等为辅料,开发出一种新型功能性复合酸菜。以感官评分为评价指标,通过单因素试验和4因素3水平正交试验,确定了食盐、紫薯、酒精、玫瑰花及辣椒的最优添加量分别为4.1%、1.0%、2.0%、0.4%及1.5%(w/w)。使用感官评分为评价指标,通过单因素优化试验分析确定了酸菜发酵的最优工艺条件为:起始p H5.5,乳酸菌接种量2.0%(乳酸菌活菌数6.8×108 cfu/m L),发酵温度35℃,发酵时间17 d。在最优配比和发酵工艺条件下,此酸菜口感最佳。     

基于辅助发酵剂制备传统奶豆腐的风味特性研究

以奶豆腐中分离的乳酸菌为研究对象,筛选出产酸能力强、风味良好、发酵时间短的乳酸菌,并对其发酵酸度、发酵终点时间和质构特性进行测定,确定传统奶豆腐辅助发酵剂菌株的配比组合。再通过辅助发酵剂的单因素和正交试验,确定传统奶豆腐的最优生产工艺,分析成品风味特性的研究。研究筛选出产酸能力强、风味良好、发酵时间短的乳酸菌4株,菌株D655、686、NDF9-3和MN1-7。经16S rDNA序列检测分析,上述菌株分别被鉴定为泡菜乳球菌(Lactococcus kimchii)、植物乳杆菌(Lactiplantibacillus plantarum)、乳酸片球菌(Pediococcus acidilactici)和粪肠球菌(Enterococcus faecium)。2种最优组合的3株菌配比发酵试验结果表明,最佳组合为D655∶686∶NDF9-3=5∶2∶3。将该组合作为辅助发酵剂,并以产品弹性、酸度与感官评分为指标进行工艺优化,最佳辅助发酵剂的添加量3%、发酵温度25℃、排乳清温度65℃,此时的奶豆腐弹性(0.92±0.05) g、酸度(70±1.2)°T、感官评分为(83±0.2)分。试验组的...     

刺梨凝固型酸奶的发酵工艺研究

研究了刺梨及蜂蜜制备的凝固型酸奶的发酵工艺,考察刺梨汁添加量、发酵温度、蜂蜜添加量、乳酸菌接种量及发酵时间对刺梨酸奶感官品质的影响。在单因素试验的基础上采用正交试验优化刺梨凝固型酸奶的发酵工艺。结果表明,刺梨凝固型酸奶最佳发酵条件为：刺梨汁添加量30%、蜂蜜添加量10%、乳酸菌接种量0.15%、发酵温度42 ℃和发酵时间9 h。在此条件下,所得刺梨凝固型酸奶感官评分为92.5分,质地均匀、凝结状态良好、口感细腻,且有浓郁的乳香味和刺梨风味。     

腌腊肉制品中乳酸菌的筛选鉴定及其在腊肠中的应用

为筛选适合传统腌腊肉制品的优良乳酸菌菌株,从多种农家自制传统腌腊肉制品中分离纯化出9株优势乳酸菌。通过发酵特性筛选,得到一株性状优良菌株10M-7,并制备该菌株的干粉发酵剂,以未接种发酵剂腊肠为对照,分析此发酵剂对腊肠感官品质和微生物变化的影响。结果表明,10M-7菌株具有良好的产酸特性和抑菌性能。根据形态学、生理生化特征和16S rRNA序列分析,鉴定其为植物乳杆菌,采用冷冻干燥法制备纯种发酵剂,并制作人工发酵腊肠。发酵剂组pH值在初期便迅速下降,且始终低于对照组;发酵剂组乳酸菌迅速生长繁殖,且葡萄球菌和大肠杆菌数量与对照组相比明显降低。感官评价表明,当添加量为10~4CFU/g原料肉时,能够很好地保持和改善产品风味,使产品整体感觉更好。     

复合发酵剂对鲜食里脊火腿品质特性的影响

以植物乳杆菌（Lactobacillus plantarum）和木糖葡萄球菌（Staphylococcus xylosus）为复合发酵剂,以产品的色差、pH值、质构和感官指标为依据研究菌种接种量、菌种配比和发酵温度对发酵里脊火腿品质的影响。结果表明：根据单因素试验结果,采用Box-Behnken试验设计建立响应面分析模型,确定发酵里脊火腿的最佳工艺参数为添加植物乳杆菌和木糖葡萄球菌为复合发酵剂,菌种接种量为107 CFU/g、菌种配比为1.50∶1、发酵温度为30 ℃,此条件下制得的发酵里脊火腿的感官评分为82.55 分,与模型理论值接近。在此条件下加工所得的发酵里脊火腿口感较佳、滋味鲜美、综合品质良好。     

浅渍法发酵豇豆的工艺优化

以具有降解亚硝酸盐功能的植物乳杆菌（Lactobacillus plantarum）SD-7和具有优良抗氧化能力的植物乳杆菌（Lactobacillus plantarum）FM-LP-9为复合发酵剂（1∶1），采用浅渍法发酵豇豆。以硬度和感官评分为考察指标，通过单因素试验及响应面试验研究复合发酵剂接种量、发酵温度和发酵时间对浅渍法发酵豇豆品质的影响。结果表明，最佳发酵工艺条件为发酵温度25 ℃，接种量5%，发酵时间125 h，在此优化条件下，得到的浅渍法发酵豇豆硬度为47.31 N，感官评分为90.98分，香气浓郁、口感脆嫩。     

发酵型酸汤味牛肉干的发酵工艺研究及品质分析

以感官评分为评价指标,研究不同复合发酵剂添加量、发酵温度、发酵时间对发酵型酸汤味牛肉干品质的影响。结果表明,最佳发酵工艺条件为复合发酵剂（乳酸菌∶酵母菌=3∶1）添加量为2.2%,酸汤添加量为8%,蜂蜜添加量为10%,食盐添加量为1%;30 ℃发酵21 h。在此优化条件下,发酵型酸汤味牛肉干出品率42.22%,亚硝酸盐含量0.02 mg/kg,水分含量35.30 g/100 g,脂肪含量19.88 g/100 g,蛋白质含量36.31 g/100 g,pH值为5.21,总糖含量8.07 g/100 g。发酵型酸汤味牛肉干的质量指标符合牛肉干相关标准要求,比自然发酵酸汤味牛肉干的品质好。     

Effects of indigenous starter cultures on the microbial and physicochemical characteristics of Urutan, a Balinese fermented sausage

Urutan is a Balinese traditional dry fermented sausage prepared from lean pork and various kinds of spice. Urutan is different from the European sausages, because it is fermented under warm condition with fluctuating temperatures of approximately 25 degrees C at night to 50 degrees C during sun drying. In this study, two of the 71 strains of lactic acid bacteria (LAB) isolated from natural urutan fermentation were used as starter cultures: Lactobacillus plantarum U201, the dominant LAB, and Pediococcus acidilactici U318, a bacteriocin producer. A soft urutan with yellowish brown color was produced using these strains as multiple starters. The starter cultures grew in characteristic succession which reconstructed the natural fermentation process. Lactobacilli were dominant until 48 h fermentation and pediococci dominated at the later stage of fermentation. Proliferation of starter cultures produced lactic acid which resulted in the decrease in pH and coagulation of soluble protein in urutan. Both strains could eliminate the Enterobacteriaceae in urutan after 24 h fermentation, and could suppress and eliminate the occurrence of micrococci at 120 h fermentation. By using a single starter culture, no succession was observed to occur in urutan and the time of elimination of Enterobacteriaceae was delayed. Thus, the strains of L. plantarum U201 and P. acidilactici U318 have great potential for use as multiple starter cultures in urutan fermentation.     

葛根糯米混合甜酒酿发酵工艺研究

以荆门地区葛根、糯米为原料,接种甜酒曲进行混合甜酒酿发酵。选取葛根与糯米的比例、酒曲接种量、发酵温度、发酵时间为条件,采用单因素试验和正交试验对混合甜酒酿的发酵工艺进行优化。结果表明,最佳发酵工艺为葛根与糯米质量比为1.0∶1.5、酒曲接种量为2.0%、发酵温度为30 ℃,发酵时间为3 d,在此条件下,制得的甜酒酿感官评分为85分,总糖含量为35.4%,酒精度为3.3%vol,黄酮含量为4.2 mg/100 mL,总酸含量为82.3 mg/100 mL（以柠檬酸计）。     

Inoculum size of co-fermentative culture affects the sensory quality and volatile metabolome of fermented milk over storage

Lacticaseibacillus paracasei PC-01 is a probiotic candidate isolated from naturally fermented yak milk in Lhasa, Tibet, and it has been shown to possess excellent milk fermentation properties. This study used Lacticaseibacillus paracasei PC-01 as a co-fermentation strain to investigate the effect of inoculum size with a commercial starter in milk fermentation on the product flavor and profile of volatile metabolites over 28 d of cold storage. Lacticaseibacillus paracasei PC-01 was allowed to ferment in pasteurized milk with or without the commercial starter (YF-L904) at 42°C until the pH decreased to 4.5. The finished fermented milks were stored at 10°C for 28 d. Milk samples were taken at hour 0 (before fermentation) and then at d 1, 14, and 28 of cold storage. Different inoculum sizes of Lacticaseibacillus paracasei PC-01 had no significant effect on pH or titratable acidity during storage of fermented milk. Viable counts of strain PC-01 continued to increase during cold storage of the fermented milk. Generally, as storage of fermented milk proceeded, the overall sensory quality score decreased in all groups. However, the overall sensory scores of PC-01-M were generally higher than those of other groups, suggesting that a medium dose of Lacticaseibacillus paracasei PC-01 had the most obvious effect of slowing the decline in sensory quality of fermented milk during storage. Changes in sensory scores and consumer preferences were accompanied by increases in both the quantity and variety of key volatile metabolites in fermented milk during fermentation, post-ripening (d 1), and storage. Major differentially abundant metabolites, including acetaldehyde, methyl ketones, medium-chain and short-chain fatty acids, 2,3-butanedione, and acetoin, were enriched in fermented milks rated highly in the sensory evaluation. Our data confirmed that the inoculum size of co-fermentative culture affected the sensory quality and volatile metabolome of fermented milk over storage, and an optimal range of co-fermentative culture was titrated in this work.     

乳酸菌发酵牛肉的工艺条件优化

通过单因素试验和响应面方法优化乳酸菌发酵牛肉的工艺,采用乳酸菌(内含保加利亚乳杆菌、嗜热链球菌)对新鲜牛肉进行发酵,对所得牛肉的pH值进行测定.结果表明:乳酸菌发酵牛肉的最佳发酵条件为葡萄糖添加量2.5％、食盐添加量0.3％、乳酸菌添加量2.5％,在酸性环境下进行乳酸菌发酵牛肉,能够有效的抑制微生物生长繁殖,能延长新鲜牛肉的保质期.     

Kefir粒发酵过程中牛乳体系的品质变化

为明确开菲尔粒(Kefir grains)在发酵过程中对牛乳体系品质变化的影响。本文将Kefir粒作为发酵剂应用于牛乳体系中,研究接种量、发酵时间和发酵温度对牛乳酸度、主要风味成分和流变性质的影响。结果表明,接种量、发酵温度、发酵时间对Kefir粒发酵作用的影响复杂。分析酸度变化的规律可知,相同条件下,接种量越大,酸度越高;电子鼻测定发酵乳中主要风味物质的变化发现,发酵温度越高,Kefir粒中的乳酸菌和酵母生长越快,产生风味物质的时间越短,但是菌种过快生长会导致发酵乳风味变差;流变仪测定发酵乳黏弹性、流动常数的变化可知,Kefir发酵乳的复合黏度随角频率增大而减小,储能模量G'和损耗模量G″随温度上升而增大,G'始终大于G″,tanδ始终小于1,体系呈现弹性特征。综合考虑实验结果和成本,选用在30℃条件下,接种量为0.40%的Kefir粒发酵48 h得到的酸度为86 °T,最终产品性质较为稳定,感官品质较为优良,这对Kefir发酵乳的工业化生产具有一定的指导意义。     

Safety improvement and preservation of typical sensory qualities of traditional dry fermented sausages using autochthonous starter cultures

Traditional dry fermented sausages are manufactured without addition of starter cultures in small-scale processing units, their fermentation relying on indigenous microflora. Characterisation and control of these specific bacteria are essential for the sensory quality and the safety of the sausages. The aim of this study was to develop an autochthonous starter culture that improves safety while preserving the typical sensory characteristics of traditional sausages. An autochthonous starter composed of Lactobacillus sakei, Staphylococcus equorum and Staphylococcus succinus isolated from a traditional fermented sausage was developed. These strains were tested for their susceptibility to antibiotics and their production of biogenic amines. This starter was evaluated in situ at the French traditional processing unit where the strains had been isolated. Effects of the autochthonous starter were assessed by analysing the microbial, physico-chemical, biochemical and sensory characteristics of the sausages. Inoculation with the chosen species was confirmed using known species-specific PCR assays for L. sakei and S. equorum and a species-specific PCR assay developed in this study for S. succinus. Strains were monitored by pulse-field gel electrophoresis typing. Addition of autochthonous microbial starter cultures improved safety compared with the traditional natural fermentation of sausages, by inhibiting the pathogen Listeria monocytogenes, decreasing the level of biogenic amines and by limiting fatty acid and cholesterol oxidation. Moreover, autochthonous starter did not affect the typical sensory quality of the traditional sausages. This is the first time to our knowledge that selection, development and validation in situ of autochthonous starter cultures have been carried out, and also the first time that S. equorum together with S. succinus have been used as starter cultures for meat fermentation. Use of autochthonous starter cultures is an effective tool for limiting the formation of unsafe compounds in traditional sausage while preserving their original and specific sensory quality.