不同腌制条件下大叶麻竹笋质构特性及色泽变化规律的研究

以大叶麻竹笋为原料,研究了大叶麻竹笋腌制前后质构和色泽的变化与食盐浓度、温度的关系。研究结果表明:大叶麻竹笋经腌制后,反映其质构特性的硬度、内聚性和咀嚼性三个质地参数的数值都会降低,且腌制食盐浓度越低、温度越高,三个质地参数的数值降低的越多。同时,大叶麻竹笋经腌制后,会失去原有的色泽,腌制食盐浓度和温度越高,大叶麻竹笋失色越严重。      

腌制条件对大叶麻竹笋硬度的影响

研究大叶麻竹笋腌制过程中硬度与食盐浓度、温度、氯化钙和焦亚硫酸钠添加量、样品厚度的关系。研究结果表明:各腌制条件对样品硬度的变化都有较大影响,具体表现为:食盐浓度越高、环境温度越低、氯化钙和焦亚硫酸钠添加量越大、样品厚度越厚,腌制大叶麻竹笋的硬度降低的越少。     

腌制加工对麻竹笋氨基酸含量的影响

为了评价腌制加工对麻竹笋氨基酸含量的影响,以大叶麻竹笋为实验原料,研究了麻竹笋氨基酸含量在腌制加工前后的变化,并比较了不同腌制盐浓度之间的差异。结果表明:与鲜样相比,腌制加工以后麻竹笋中的总氨基酸含量明显下降,在3%、11%和19%盐浓度的腌制样品中总氨基酸含量分别降低了58.1%、54.8%和53.1%,同时,腌制加工后麻竹笋中呈味氨基酸的含量和组成比例发生了变化。此外,麻竹笋鲜样中7种必需氨基酸的含量占氨基酸总量的36.8%,而3种腌制样品中这一比例分别为42.7%、41.8%和42.7%。所得研究结果将为麻竹笋腌制加工过程中食用品质的评价提供理论依据。      

大叶麻竹笋腌制过程中主要营养成分的变化

以大叶麻竹笋为原料,研究其在4种不同腌制方式过程中蛋白质、可溶性糖、粗纤维、VC和矿物质等营养成分含量的变化。结果表明:大叶麻竹笋在腌制过程中蛋白质、可溶性糖、粗纤维、VC和矿物质等营养成分的含量发生了明显变化。腌制90d后,发酵性腌制和非发酵性腌制蛋白质含量分别降低了87.01%和77.36%,可溶性糖的含量分别下降了98.17%和86.63%,VC的含量分别下降了71.29%和90.87%,粗纤维的含量分别下降了39.27%和45.01%。腌制样品中Ca和K的含量比鲜样品分别增加了26.00%和3.15%;P、Fe和Zn的含量分别降低了94.31%、62.53%和29.17%。     

腌制加工对麻竹笋质构和微观结构及色泽的影响

为了评价腌制加工对麻竹笋食用品质的影响,以大叶麻竹笋为实验原料,研究麻竹笋的质构、微观结构和色泽等在腌制加工前后的变化,并比较不同腌制食盐质量浓度之间的差异。结果表明：腌制加工以后麻竹笋的硬度、凝聚性、咀嚼性等质构特性显著下降,不同腌制食盐质量浓度对硬度有显著影响,而对凝聚性和咀嚼性的影响不显著。通过扫描电镜观察发现,麻竹笋在腌制加工以后,细胞壁呈现出明显的皱缩,细胞间隙增大,部分薄壁组织细胞出现破损。与鲜样相比,腌制加工后麻竹笋的亮度L*降低,黄色度b*升高,总色差ΔE＞2,说明腌制加工前后麻竹笋的色泽变化差异较大,可以从视觉上比较容易分辨。     

Monitoring of the bacterial communities of bamboo shoots (Dendrocalamus latiflorus) during pickling process

The diversity and dynamics of the dominant bacterial communities arising during the pickling process of bamboo shoots (Dendrocalamus latiflorus) were investigated by nested polymerase chain reaction denaturing gradient gel electrophoresis combined with quantitative real‐time polymerase chain reaction. Results showed only several kinds of halophilic bacteria during early sampling time (0?3 days). After pickling for 7 days, Lactococcus lactis significantly increased (P < 0.05, quantities were 6.39 × 10⁵ copies μL^?1) and became the first dominant bacterium. After pickling for 14 days, Weissella sp. bands appeared and quickly became dominant on the 21st day (4.07 × 10⁶ copies μL^?1). As maturation progressed, Lc. lactis decreased in intensity whereas Weissella sp. increased in intensity. Finally, the quantities of Weissella sp. (2.50 × 10⁷ copies μL^?1) became higher than those of Lc. lactis (1.43 × 10⁷ copies μL^?1) after pickling for 56 days. The pickling process was initiated by Lc. lactis, followed by Lc. lactis and Weissella sp., and was finally succeeded by Weissella sp.     

大叶麻竹笋腌制过程中质地的变化

应用质构仪质地多面分析(TPA)试验方法,研究了大叶麻竹笋在不同食盐浓度腌制条件下及腌制过程中的质地变化。研究结果表明:大叶麻竹笋腌制过程中的硬度、咀嚼性、内聚性、弹性与回复性呈下降趋势,腌制食盐浓度越低,上述5个质地参数的数值降低的越多;黏着性呈上升趋势,腌制食盐浓度越低,其数值增加的越多。大叶麻竹笋TPA测试各质地参数间的相关性分析表明,硬度、咀嚼性、内聚性、弹性和回复性可用于更好地评价腌制大叶麻竹笋质地的变化。     

麻竹笋罐头贮藏过程中质构、果胶和色泽的变化

以麻竹笋为实验原料,研究麻竹笋罐头在常温（25 ℃）和低温（4 ℃）贮藏过程中质构、果胶和色泽的变化,并探讨麻竹笋罐头的硬度与果胶变化的相关性。结果表明：麻竹笋罐头在贮藏过程中硬度、原果胶和水溶性果胶含量逐渐下降,贮藏120 d后,常温贮藏和低温贮藏条件下麻竹笋的硬度分别下降39.5%和27.1%,原果胶含量分别下降66.4%和62.8%,水溶性果胶含量分别下降68.1%和75.7%。各果胶组分与硬度之间呈现较好的相关性,而原果胶与硬度之间的相关性高于水溶性果胶与硬度之间的相关性。麻竹笋罐头贮藏过程中亮度值L*和红绿值a*逐渐减小,黄蓝值b*逐渐增加;常温和低温分别贮藏30 d和70 d时,总色差ΔE＞2。     

大叶麻竹笋腌制过程中质地变软原因探究

以大叶麻竹笋为原料,研究其腌制过程中总酸、水分含量、NaCl含量、乙醇不溶物含量、原果胶含量、纤维素含量和木质素含量与硬度的关系。同时,对样品腌制过程中的微观结构进行观察。结果表明：大叶麻竹笋腌制过程中硬度的变化与总酸含量、NaCl含量、乙醇不溶物含量、原果胶含量和纤维素含量密切相关。同时,大叶麻竹笋腌制过程中组织微观结构发生明显的变化。     

食盐质量浓度对大叶麻竹笋腌制过程中品质特性的影响

以大叶麻竹笋为原料,研究不同食盐质量浓度对大叶麻竹笋腌制过程中pH值、总酸、水分、NaCl、乙醇不溶物(AIS)、Ca2+、Mg2+、硬度和组织微观结构等的影响。结果表明:随着食盐质量浓度的增加,腌制后大叶麻竹笋的pH值,与硬度密切相关的AIS、Ca2+和Mg2+含量、硬度,细胞结构中的中胶层厚度等均增加,但其总酸和水分含量却降低。说明高食盐质量浓度腌制大叶麻竹笋,有助于保持其硬度,减缓其质地的变软。     

乳酸菌在水煮笋罐头漂洗工序中的应用

从水煮笋漂洗液中分离乳酸菌种,经过培养筛选,应用于水煮笋漂洗工序,可使漂洗时间由常规的3～5d缩短至26h左右,可为企业降低生产成本,提高产品质量和产量.     

实时荧光定量PCR技术监测腌制麻竹笋中乳酸乳球菌动态变化

采用实时荧光定量聚合酶链式反应（quantitative real-time polymerase chain reaction,qRT-PCR）技术定量监测6 g/100 mL盐质量浓度腌制麻竹笋中乳酸乳球菌（Lactococcus lactis）的动态变化。经乳酸乳球菌标准菌株基因组DNA提取、标准阳性质粒制备、标准曲线绘制、各时期竹笋腌制发酵液中细菌基因组DNA提取和乳酸乳球菌qRTPCR特异性扩增,对腌制液中乳酸乳球菌进行定量检测。结果表明,在腌制过程中（0～63 d）,随着腌制时间的延长,乳酸乳球菌含量逐渐升高,在腌制14 d时达到最大值（4.63×108 copies/μL）,与0 d（2.41×102 copies/μL）相比增加了6 个数量级,而后浓度缓慢降低,在腌制63 d时浓度为5.02×106 copies/μL。qRT-PCR技术为定量监测腌制麻竹笋中微生物的动态变化提供了一条可靠、快速的有效途径。     

自然发酵酸笋中乳酸菌的筛选鉴定及益生特性研究

为筛选自然发酵酸笋中的益生乳酸菌,采用MRS培养基分离,经生理生化实验及16S rDNA序列分析鉴定,通过溶血实验评价安全性以及耐酸耐胆盐实验评价耐受性,并测定乳酸菌体外抗氧化性。结果表明,共分离到69株乳酸菌,隶属于2个科3个属,分别为乳杆菌属（Lactobacillus）、片球菌属（Pediococcus）、链球菌属（Streptococcus）,均为γ-溶血的安全菌株,且均对0.3%胆盐具有良好耐受性,其中41株乳酸菌耐pH 2.0酸性条件,从中优选出的17株乳酸菌对人工胃肠液均有良好耐受性。4株短乳杆菌（Z1-02、ZR2-14、ZR2-12、ZR2-22）和2株消化乳杆菌（ZR1-02、ZR1-05）的1,1-二苯基-2-三硝基苯肼（DPPH）自由基清除率、2,2'-联氮-双-3-乙基苯并噻唑啉-6-磺酸（ABTS）自由基清除率、还原能力均分别＞62%、79%、0.393,其中乳杆菌Z1-02的综合抗氧化能力最强,这6株乳酸菌具备优良的益生性能和体外抗氧化活性。     

气相色谱法同时测定竹笋中毒死蜱、五氯硝基苯、氰戊菊酯和溴氰菊酯农药残留量

建立竹笋中毒死蜱、五氯硝基苯、氰戊菊酯和溴氰菊酯残留量同时测定的气相色谱检测技术。竹笋样品用乙腈提取,经PSA和石墨化碳黑净化,气相色谱电子捕获检测器(GC-ECD)检测,外标法定量。在0.05～0.80mg/kg的添加水平,4种农药的平均回收率在87.4%～117.8%之间,相对标准偏差在0.64%～5.52%,该方法的检出限为0.002～0.010mg/kg。该方法的灵敏度、准确度和精密度均符合农药残留测定的要求,可以对竹笋中这4种农药残留量进行有效监控。     

Isolation and characterization of lactic acid bacteria from jiang‐sun (fermented bamboo shoots), a traditional fermented food in Taiwan

BACKGROUND: In this study, lactic acid bacteria (LAB) were isolated, characterized and identified from jiang‐sun (fermented bamboo shoots; a traditional fermented food in Taiwan). Samples were collected at seven time intervals from a fixed fermenting bucket during the fermentation process of jiang‐sun and its initial ingredients, dochi (fermented soybeans) and bamboo shoots. RESULTS: A total of 57 LAB cultures were isolated; 42 cultures were isolated from jiang‐sun samples and 15 cultures were isolated from dochi and bamboo shoots. These isolates were characterized phenotypically and then divided into three groups (A–C) by restriction fragment length polymorphism analysis and sequencing of 16S ribosomal DNA. Alteration of microbial populations during the fermentation process was observed. While various LAB were found in the dochi and bamboo shoots, it was mostly replaced by Lactobacillus plantarum after 1 day of fermentation. Furthermore, the antibacterial activities of the isolates were determined, and one Enterococcus faecium strain showed inhibitory activity against all the indicator strains. CONCLUSION: Results suggest that L. plantarum is the main LAB present during the fermentation of jiang‐sun. To our knowledge, this is the first report describing the distribution and varieties of LAB that exist in the jiang‐sun fermentation process. Copyright © 2010 Society of Chemical Industry     

鱼腐乳发酵过程中游离氨基酸含量及抗氧化活性的变化

利用总状毛霉（Mucor racemosus）和红曲霉（Monascus）F1对鱼豆腐进行发酵研制鱼腐乳,对鱼腐乳发酵过程中的游离氨基酸及抗氧化活性的变化规律进行分析。结果表明：在发酵过程中,鲜味氨基酸、必需氨基酸、疏水氨基酸、总氨基酸的含量都呈逐渐升高的趋势,在后熟第28天时分别达到了138.57 mg/100 g、491.68 mg/100 g、340.06 mg/100 g、915.77 mg/100 g。在发酵过程中DPPH自由基清除率和羟自由基清除率也呈逐渐升高的趋势,在后熟第28天时分别达到70.30%和63.11%,分别比发酵开始时提高了53.09%和24.14%。     

Lipid,fatty acid,protein, amino acid and ash contents in four Brazilian red algae species

Four species of marine benthic algae (Laurencia filiformis, L. intricata, Gracilaria domingensis and G. birdiae) that belong to the phylum Rhodophyta were collected in Espírito Santo State, Brazil and investigated concerning their biochemical composition (fatty acid, total lipid, soluble proteins, amino acid and ash). The total content of lipid (% dry weight) ranged from 1.1% to 6.2%; fatty acid from 0.7% to 1.0%; soluble protein from 4.6% to 18.3%, amino acid from 6.7% to 11.3% and ash from 22.5% to 38.4%. Judging from their composition, the four species of algae appear to be potential sources of dietary proteins, amino acids, lipids and essential fatty acids for humans and animals.