4种嗜盐古菌发酵的龙头鱼鱼露特性比较

以去除内脏的龙头鱼为原料,利用自行筛选的4种嗜盐古菌做发酵剂生产鱼露。通过测定发酵4.5个月后氨基酸态氮(AAN)、亚硝酸盐、总胺、总酸、挥发性盐基氮(TVB-N)、可溶性总氮(TSN)、组胺、游离氨基酸组成、挥发性风味物质含量变化,从4种嗜盐菌中挑选出更加适宜发酵鱼露的菌种。接种TBN4的鱼露在4种嗜盐古菌发酵的鱼露中氨基酸态氮、可溶性总氮含量、挥发性风味物质总量最高,游离氨基酸含量丰富,且组胺含量最低。而接种9738的鱼露氨基酸态氮含量最高,接种RO2-11的鱼露挥发性风味物质总量较高,组胺含量较低。     

发酵牛肉干加工中理化特性与风味品质分析

为探究发酵牛肉干不同加工阶段理化性质和风味品质的变化,以牛臀肉为原料,接种木糖葡萄球菌和清酒乳杆菌制作发酵牛肉干,并对牛肉干在发酵前后及成品的营养成分、质构、色泽等理化特性及游离氨基酸、脂肪酸组成和挥发性风味物质对比分析。结果表明,与发酵前相比,接种复合发酵剂的牛肉干pH值、水分活度、亚硝酸盐残留量、硬度、咀嚼性均显著降低（P＜0.05）;红度值和游离氨基酸含量显著增加,且鲜味氨基酸占比最高;游离脂肪酸以棕榈酸、硬脂酸、油酸、亚油酸为主,其中油酸占比最大;发酵后牛肉检出47 种挥发性化合物,高于发酵前42 种,提高了牛肉干中醛、醇、酚、酯、酸、含氮及其他化合物的种类和相对含量。发酵牛肉干质构及色泽明显改善,游离氨基酸和脂肪酸含量增加,产品营养价值、风味品质及质量安全显著提高。     

一种涂抹型核桃奶酪的研制

本研究以去皮核桃仁为原料,研究奶酪制作工艺,开发一种发酵涂抹型核桃奶酪。以感官评分、游离氨基酸为参考指标,筛选最适的酶解工艺条件;单因素试验结合响应面优化,研究发酵时间和奶油、乳清蛋白、蔗糖添加量对奶酪凝乳的影响,确定核桃奶酪工艺。结果表明:添加脂肪酶Palatase 20000 L、风味蛋白酶(添加比列为1:2,添加量为0.2%)复合酶解核桃乳时酶解效果最好,感官评分最高,游离氨基酸质量分数为(764±44)mg/100g;响应面优化结果显示乳清蛋白、奶油、蔗糖的添加量分别为1.56%、0.81%、6.37%,发酵时间24 h时,核桃奶酪感官评分达到最高(90.5分)。比较核桃发酵前后部分风味物质的含量差异,发现核桃奶酪中的游离氨基酸和游离脂肪酸含量均显著提高,其中游离氨基酸总量由发酵前的279.97 mg/kg增加到1262.02 mg/kg,对产品独特风味的形成贡献率较高。此工艺制备的核桃奶酪风味十足,营养价值高,具有较佳的感官品质,可为核桃产业的综合开发提供参考。     

乳酸菌培养物的生长特性及其对豆奶质构和风味的影响

研究了Lactobacillus casei (LC), Lactobacillus helveticus (LH) and Lactobacillus rahmnosus (Lactobacillus casei subsp. rahmnosus 6013) (LR)生长特性及其对大豆奶酪风味的影响.研究表明,经过6 h的发酵,LC、LH和LR的菌落数分别增长至8.74、7.69和8.69 log (CFU/mL);37 ℃时,分别接种LC、LH、LR和添加有Glucono-δ-内酯(GDL)的大豆牛奶都明显出现可滴定酸度增加、pH减少的现象.这三种乳酸菌都能够利用大豆糖源.经质构分析发现,菌种可引起大豆牛奶质构发生变化,其凝乳的能力可与GDL媲美.菌种通过产酶、产酸而水解大豆蛋白,从而导致质构变化形成凝乳.这些菌种可释放18种游离氨基酸(FAA),其中包括可作为奶酪风味物质前体化合物的天门冬氨酸、异亮氨酸、亮氨酸、蛋氨酸、苯丙氨酸和缬氨酸.这些菌种均能利用大豆脂肪酸(FA),而在大豆凝乳中出现某些FA消失的现象表明所选的菌种还能分别完全消耗特定的FA.可见,这三种乳酸菌在大豆牛奶中可引起质感及风味前体物的变化,正是生产大豆奶酪所必需的效果,故选择它们作为制备大豆奶酪的适用菌种.     

不同菌种大豆干酪后熟过程的研究

研究了3种不同大豆干酪后熟过程的变化情况。结果表明,L.rhamnosus+S.carnosus大豆干酪具有最低的pH和最高的酸度,同时具有最高的氨基氮含量和最高的活菌数。游离氨基酸分析表明,L.rhamnosus+S.carnosus大豆干酪中的游离氨基酸总量最高;L.rhamnosus大豆干酪降解产生的游离氨基酸以谷氨酸和精氨酸为主,S.carnosus大豆干酪和L.rhamnosus+S.carnosus大豆干酪降解产生的游离氨基酸则以色氨酸为主。脂肪酸分析表明,L.rhamnosus+S.carnosus大豆干酪C20以上的长链脂肪酸得到更加充分的降解。     

植物乳杆菌基因yesN对中式发酵香肠风味的影响

目的:研究植物乳杆菌基因yesN缺失对中式发酵香肠挥发性风味、总酸、总游离氨基酸的影响。方法:采用植物乳杆菌基因yesN缺失菌株SNB制备中式发酵香肠,检测发酵香肠挥发性风味物质成分、酸度、总游离氨基酸等指标,并与自然发酵制备香肠和以野生植物乳杆菌为发酵剂制备的香肠进行对比,确定蔗糖利用缺陷植物乳杆菌菌株对中式发酵香肠风味的影响。结果显示:突变菌株在支链氨基酸降解形成的风味物质,总游离氨基酸、总可滴定酸等指标均更接近于自然发酵香肠。结论:突变菌株具有作为模型菌株应用于中式发酵香肠发酵剂筛选的潜力。     

植物乳杆菌和棒状乳杆菌对发酵萝卜干风味品质的影响

以白萝卜为原料,经初步脱水制成半干萝卜干,分别接种植物乳杆菌L1和棒状乳杆菌L3以及混合菌种发酵萝卜干。以自然腌制发酵为对照,测定萝卜干发酵过程中的pH值和总酸的变化,并对发酵后萝卜干的质构、色差、氨基酸成分和挥发性风味物质进行分析,探讨2种乳酸菌对萝卜干发酵风味品质的影响。结果表明,接种乳酸菌发酵能加快pH值的下降和总酸的上升。混菌发酵的萝卜干总酸和游离氨基酸含量最高,分别达到0.729 g/100 g和16.01 mg/g。接种棒状乳杆菌L3的萝卜干色泽与未发酵萝卜干最为接近。接种植物乳杆菌L1的萝卜干质地、口感都最好。从4组萝卜干中共检测出挥发性风味成分61种,混菌发酵的风味物质种类虽不是最多但风味评价最好,某些特有的香气较突出。综合品质指标数据和感官评价结果,最后选用混合菌种作为发酵剂,所得产品的色泽、质地和风味俱佳,品质高于自然发酵和单一菌种发酵的萝卜干。     

乳酸菌发酵制备大豆奶酪豆坯的工艺研究(英文)

采用3种乳酸茵干酪乳杆菌（LC）、瑞士乳杆菌（LH）和干酪乳杆菌鼠李糖亚种6013（LR）和葡萄糖酸内酯（GDL）凝固豆乳制备豆坯,并对其质构和风味进一步改善。在6h的凝乳发酵中可以发现LC＋LH样品中发酵剂生长良好,豆孔pH下降比LC＋LH＋LR样品要多。GDL的添加可以促进发酵剂生长,降低豆乳pH,但是它对豆坯的质构的改善并不明显。在GDL＋LH＋LC＋LR制备的豆坯样品中,检测到7种提供风味的和另外11种不同种类不同含量的游离氨基酸（FAA）,同时,该样品的脂肪酸（FA）情况也发生显著变化（C18：3．C20：0,C20：1和C22：0除外）。除了10种常规大豆脂肪酸外,C22：1和C24：0也被检测到。后熟过程中这些游离氨基酸和脂肪酸的变化将会导致大豆奶酪质构和风味的改善和提高。从质构和风味上讲,LC＋LH制备的豆坯是最好的,其次是LC＋LH＋GDL制备的豆坯。     

新疆特色酸凝奶酪成熟过程中产生的非挥发性风味物质研究

非挥发性风味物质对奶酪的口味有重要影响,文中对酸凝奶酪成熟过程中非挥发性风味物质含量的变化进行了研究,结果表明:随着奶酪成熟时间的延长有机酸总量和各种有机酸含量变化差异极显著(P<0.01),主要有机酸乳酸含量最高达到10.75 mg/g;各种游离氨基酸含量处于动态变化过程,总游离氨基酸含量变化显著(P<0.05),缬氨酸和亮氨酸是优势氨基酸,最大含量为35.19 mg/100 g和27.06 mg/100 g;游离脂肪酸总量变化差异极显著(P<0.01)。随着成熟时间的延长,奶酪的营养价值更高,口味更浓郁。     

微生物发酵剂对兔肉脯游离氨基酸含量的影响

将植物乳杆菌（Lactobacillus plantarum）、木糖葡萄球菌（Staphylococcus xylosus）、汉逊德巴利酵母菌（Dabaryomyces hansenii）接种于兔肉糜中,发酵及烘烤制成兔肉脯,研究不同菌种对产品中游离氨基酸含量的影响。结果表明：三菌种单独发酵处理组中,游离氨基酸总量由高到低分别为：葡萄球菌处理组＞酵母菌处理组＞乳酸菌处理组,3 个处理组游离氨基酸总量均高于空白对照组,说明添加发酵剂促进了兔肉脯中蛋白质的分解,且其在兔肉脯中分解蛋白质产生游离氨基酸的能力依次递减;三菌种单独发酵处理组中,各种游离氨基酸的含量有增有减,说明不同发酵剂对蛋白质分解游离氨基酸的影响不同;三菌种混合发酵处理组总游离氨基酸含量及各氨基酸含量均高于空白对照组和单菌处理组,说明三菌种复合发酵分解蛋白质产生游离氨基酸的效果相对最好。     

混合型大豆干酪成熟特性的研究

对混合型大豆干酪的成熟特性进行了研究。检测了混合型大豆干酪成熟过程中游离脂肪酸和氨基酸含量的变化,在扫描电镜下观察了不同成熟条件下干酪的微观结构。结果表明,成熟温度对游离脂肪酸含量影响不显著,对游离氨基酸含量影响显著;随着成熟时间的延长,饱和脂肪酸与不饱和脂肪酸含量之比下降,游离氨基酸含量变化较为显著;成熟对混合型大豆干酪的微观结构影响很大,使得干酪质地越来越致密均匀。     

大豆品种对双蛋白干酪得率和品质特性的影响

用8种不同品种大豆制作的豆乳与牛奶混合,按照切达干酪生产工艺制作双蛋白切达干酪,以同批次纯牛奶制作的干酪为对照组,对产品的得率、色泽、质构和感官特性等指标进行了分析和比较。实验结果表明,各组双蛋白干酪均比纯牛奶干酪的得率高,各组双蛋白干酪之间得率存在较大差异。质构测定结果表明,不同大豆品种生产的双蛋白干酪在硬度、弹性和粘聚性等指标方面具有较大差异。感官评价中,除添加小粒豆8号豆乳的双蛋白干酪带有较浓豆腥味外,其余组与对照组相差不大。相关性分析结果表明,大豆蛋白中球蛋白和β-伴球蛋白的比值(11S/7S)与双蛋白干酪的硬度和粘聚性显著相关,而大豆的蛋白含量、脂肪含量和植酸含量等指标与双蛋白干酪的品质指标无显著相关性。     

Production of hard cheese from caprine milk by the use of two types of probiotic cultures as adjuncts

Hard cheeses (Kefalotyri-like) were manufactured from caprine milk with yoghurt as a starter (A), and with its partial replacement with the probiotic adjuncts Lactobacillus rhamnosus LC 705 (B) and/or Lactobacillus paracasei ssp. paracasei DC 412 (C). Both adjuncts retarded the growth of enterococci, and the environment in cheese B did not favour the recovery of lactic acid bacteria (LAB) on Rogosa agar. However, better recovery of the LAB population on M17 agar from cheeses B and C made with adjuncts was recorded early in ripening, and this was accompanied by a greater decrease in pH. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of whole-cell protein demonstrated that cheese C, made with Lb. paracasei ssp. paracasei as adjunct, is a better vehicle for delivery of live probiotic cells (10 ⁷   cfu/g) to the gastrointestinal tract than cheese B, made with Lb. rhamnosus ; the latter did not belong to the predominant microflora of one out of the two B cheeses. Urea-PAGE electrophoresis results indicated that adjunct lactobacilli enhanced the degradation of both α _S -casein (α _S -CN) and β-casein (β-CN). In the fresh cheese, hydrolysis of α _S -CN was more rapid than β-CN, and the free amino acid content of B and C was higher than in A. Lipolysis products were also higher in B and C than in A as ripening progressed, and the organoleptic characteristics of these cheeses resulted in higher scores, in the order C > B > A. Thus, making Kefalotyri-like cheese from caprine milk with probiotic lactobacilli, particularly Lb. paracasei ssp. paracasei, as adjunct can be considered an effective way of producing a cheese with a large number of probiotic cells.     

发酵剂用量对硬质蒙古干酪蛋白质、脂类水解和微观结构的影响

该文通过添加不同发酵剂用量制作了3种硬质蒙古干酪,并对硬质蒙古干酪的理化性质、蛋白质和脂肪水解程度、微观结构等进行了研究。结果表明,随着发酵剂用量增多,除D-乳酸含量外,其他理化指标均随发酵剂用量的增大而减小;粗蛋白质和粗脂肪的含量减少;pH 4.6-可溶性氮（SN）含量和12%三氯乙酸（TCA）-SN含量均增加,表明干酪中蛋白质和脂肪的水解程度增大;游离氨基酸和游离脂肪酸的含量增加,表明干酪的风味物质增多。随着发酵剂用量的增多,干酪酸化速度加快,质地相对松散。最终确定发酵剂使用量为1.0 g/L,在此条件下,脂肪和蛋白质的水解程度适中,游离氨基酸种类丰富,能够满足干酪风味化合物生成的需求。     

酸性蛋白酶对高盐稀态酱油发酵的影响

以高盐稀态发酵酱油为研究对象,以未添加酸性蛋白酶的样品为对照组（K）,在酱油发酵初期（0 d）添加酸性蛋白酶（1‰）的样品为实验组（S）,通过分析发酵过程（1～62 d）中酸性和中性蛋白酶活力、pH、总酸含量、氨基酸态氨含量和游离氨基酸含量的变化及生酱油的呈味氨基酸含量,考察添加外源酸性蛋白酶对酱油发酵的影响。结果表明,S组的酸性蛋白酶和中性蛋白酶活力分别为K组的2.9倍和2.1倍。发酵结束时,与K组相比,S组酱油的pH下降至4.50、总酸、氨基酸态氮含量分别增加36.71%、16.49%;游离氨基酸总含量降低13.64%,生酱油呈鲜味的谷氨酸含量由11.52 g/L降至1.26 g/L。表明酸性蛋白酶虽然能够提高原料利用率,但对酱油滋味也有一定影响。     

Influence of autochthonous Argentine goat lactobacillus in ripening of slurry cheese models

Three indigenous lactobacilli isolated from autochthonous Argentinean goat cheeses were evaluated in models of ripening of semihard goat cheeses made under microbiologically controlled conditions. Batches A, B and C were manufactured with single strain of Lactobacillus plantarum ETC17, Lactobacillus rhamnosus ETC14 and Lactobacillus casei ETC19, respectively. Lactobacilli counts showed higher values on batch C until ripening on day 18. Chemical composition did not show differences between batches. Batch C showed a higher decrease in pH on day 1, higher liberation of nitrogen water-soluble cheese extracts and higher free amino acids content up to day 18. Amino acid distribution was analysed by studying the main components.     

Amino acid composition,molecular weight distribution and antioxidant activity of protein hydrolysates of soy sauce lees

The proteins of soy sauce lees (SSLP) were hydrolysed by Alcalase in the presence of ultrasound or traditional water bath to obtain hydrolysates S2–S6. The analysis of protein content indicated that enzymatic hydrolysis could significantly improve the extraction efficiency of proteins. By determination of molecular weight distribution, >10 and 5–10 KDa fractions of native SSLP (S1) decreased during hydrolysis, whilst 3–5 KDa fraction increased. Gradual increases of free, total and antioxidant amino acids were observed for S1–S4, and the differences between S4 and S6 were slight. Tyrosine was the major free amino acid of S1–S6, whilst glutamic acid had the highest amount in total amino acid composition. S2–S6 showed stronger DPPH radical scavenging activities in a dose-dependent manner than S1. All the results suggested that ultrasound treatment showed an inhibition behaviour on the enzymatic hydrolysis of SSLP.     

1984 Award to professor Y. Pomeranz for advancement of application of agricultural and food chemistry

Differences in chemical and free amino acid compositions, microstructure and sensory quality during pickling were found between Kariesh cheese made from lactose-hydrolyzed milk and a control.Sodium caseinate and essential free amino acids are considered to be the proteinaceous and free amino acids components of this type of cheese. Differences in flavour between the two cheese types are assumed to be due to differences in free amino acid contents during pickling. The microstructure of the ripened experimental cheese was more homogeneous than that of the control cheese.Protein degradation, free amino acid concentration and fusion of casein micelles in the cheese protein matrix were increased, and the organoleptic quality of Kariesh cheese was improved, when β-galactosidase was added to the cheese milk before processing.