Recent observations on the occurrence of fishy flavour in bacon

An examination of reject bacon samples supplied directly from a factory showed that some samples described by a sensory panel as oily and fishy contained significantly higher levels of long chain polyunsaturated fatty acids (PUFA) in their fat than normal samples. When bacon samples obtained from retail outlets were similarly analysed and then subjected to sensory assessment, those found to contain long chain PUFA were given significantly higher scores for oily and fishy flavour. Observations on the fatty acid composition of fishy bacon samples as compared to non-fishy ones and further investigation into the diets of pigs producing suspect carcasses led to the conclusion that too high a content of fish products in the diet was the main cause of the problem. Contrary to what had been believed, fresh non-fishy bacon samples did not develop fishy flavour after storage at ?20°C for 15 weeks. Perceived fishiness was not related to total copper content as determined by atomic absorption spectroscopy.     

镇巴腊肉生产过程中微生物组成及多样性变化

基于高通量测序技术,对镇巴腊肉加工过程不同阶段的微生物种群组成进行鉴定和分析,同时对细菌表型及相关功能进行预测。结果表明：镇巴腊肉生产加工过程中,真菌丰度大于细菌丰度,并随着发酵时间及加工工艺变化,微生物群落存在明显的演替;镇巴腊肉中丰度最高的细菌为厚壁菌门（Firmcutes）和变形菌门（Proteobacteria）,优势细菌属随着加工步骤推进由原料肉样品中的大肠-志贺氏菌属演替为腌制时期和熏制时期的葡萄球菌属（Staphylococcus）、嗜冷杆菌属（Psychrobacter）和乳杆菌属（Latilactobacillus）;丰度最高的真菌门为子囊菌门（Ascomycota）和担子菌门（Basidiomycota）,优势真菌属由镰刀菌属（Fusarium）和被孢霉属演替为镰刀菌属（Mortierella）和德巴利氏酵母属（Debaryomyces）;基于菌落演替变化及细菌表型和功能预测,发现镇巴腊肉在加工过程中有害微生物不断减少,利于发酵的微生物逐渐增加,促进镇巴腊肉风味物质形成。     

低温贮藏对川式腊肉中蛋白质降解的影响

新鲜腊肉采用直接真空包装（A处理）和添加抗坏血酸后真空包装（B处理）后,分别在5℃和-18℃下贮藏,探讨蛋白质的降解和氨基酸组成变化。结果表明,各处理水分含量随贮藏时间的延长逐渐下降,氨基酸组成分析显示．各处理中必需氨基酸相对含量均呈增加趋势。冷藏120d时A、B处理E／N比从初始值0．65分别升至结束时的0．75和0．73．AAS从13．06分别升至44．57和51．23;冻藏处理E/N比和AAS呈先升后降趋势,冻藏120d时A、B处理E／N比从初始值0．65分别升至0．71和0．90,而AAS从13．06分别升至31．16和31．86。各处理挥发性盐基氮随贮藏时间延长不断增加,但符合SB/T10294—1998中规定二级品≤45mg／100g,超出分割冻猪肉国标、鲜、冻四分体带骨牛肉国标15mg／100g。表明短期低温贮藏和添加抗坏血酸可改善腊肉氨基酸组成,不影响腊肉食用品质。     

Investigating quality attributes and consumer acceptance of uncured, no-nitrate/nitrite-added commercial hams, bacons, and frankfurters

ABSTRACT:  Increasing demands for natural, organic, and/or preservative-free foods have resulted in the consumer availability of uncured, no-nitrate/nitrite-added processed meat and poultry products. A comprehensive understanding about the quality and sensory attributes of commercially available uncured products is unclear. The objective of this study was to determine if quality and sensory differences exist between uncured and cured meat products. Five different commercial brands (Brands A to E; 4 uncured, no-nitrate/nitrite-added, and 1 nitrite-added) of 3 product types (hams, frankfurters, and bacons) were obtained from retail supermarkets. The samples were evaluated for color, pigment content, pH, lipid oxidation, residual nitrate and nitrite content, and consumer acceptance. All brands from all product types evaluated, except for 1 bacon (Brand B), had cured color, aroma, and flavor attributes similar to the nitrite-added control (Brand E). All product types and brands contained residual nitrate and residual nitrite except for Brands B and D bacons (< 1 ppm nitrite). Lipid oxidation as measured by 2-thiobarbituric acid reactive substances revealed a large variation in the occurrence of lipid oxidation both between and within product types, with frankfurters reporting the highest levels. Color measurements indicated the majority of the brands within each product type were similar to the control. Consumer sensory ratings for surface/lean color, aroma, flavor, texture, and overall acceptance determined that variation existed. Brand E (nitrite-added control) and 1 uncured, no-nitrate/nitrite-added brand for each product type were not different ( P > 0.05) for overall acceptance and received higher scores ( P < 0.05) than all other brands within each product type.     

重组培根加工过程中N-亚硝胺及其前体物质含量的动态变化

为了明确重组培根加工过程中N-亚硝胺含量的动态变化及其影响因素,监测原料肉、腌制、蒸煮、烟熏加工环节中pH值及亚硝酸盐、生物胺、N-亚硝胺含量的动态变化,同时考察重组培根的感官品质。结果表明：随着加工的进行,重组培根pH值和亚硝酸盐残留量均呈现先上升后下降的趋势;在监测的8 种生物胺中,原料肉中仅检出精胺,随着重组培根加工的进行,生物胺的种类不断丰富,含量逐渐升高,烟熏显著加速了生物胺的生成;原料肉中仅检测出N-二甲基亚硝胺（N-nitrosodimethylamine,NDMA）和N-亚硝基吡咯烷（N-nitrosopyrrolidin,NPYR）;腌制后可检出N-甲基乙基亚硝胺（N-nitrosomethylethylamine,NMEA）、N-二丙基亚硝胺（N-nitrosodipropylamine,NDPA）、N-二丁基亚硝胺（N-nitrosodibutylamide,NDBA）和N-亚硝基哌啶（N-nitrosopiperidine,NPIP）,NDMA含量超过了国标限量; 蒸煮后新增N - 二乙基亚硝胺（ N - n i t r o s o d i e t h y l a m i n e ,NDEA）和N-亚硝基吗啉（N- n i trosomorpholine,NMOR）,且NDMA、NDPA、NDBA、NPIP含量显著升高（P＜0.05）;烟熏过程中N-亚硝胺总量显著增加（P＜0.05）,烟熏6～9 h增幅最大;重组培根的感官评分随着烟熏时间的延长显著提高（P＜0.05）。综合食用安全性和感官评分,建议制作重组培根时选择腌制16 h,热熏法（55±2） ℃烟熏6h。     

迷迭香提取物及其包结物在中式培根中的应用

研究了迷迭香提取物(RE)的化学成分、抗氧化活性及RE与其环糊精钾金属有机骨架包结物(RE-K-CD-MOF)在中式培根中的应用。结果表明:RE的主要成分为迷迭香酸等12种物质;RE具有良好的抗氧化效果,在0.5~1.5 mg/mL浓度范围内,清除DPPH自由基的能力大于BHT小于V_C,在1~5 μg/mL浓度范围内,清除OH自由基的能力大于V_C小于BHT。应用于中式培根腌制过程中脂质氧化实验表明,与对照组相比添加RE及RE-K-CD-MOF各组均具有较低的过氧化值和丙二醛含量;与添加RE各组相比,添加RE-K-CD-MOF各组表现出更好的稳定性和抑制脂质氧化效果。与添加0.3% RE相比,添加0.3% RE-K-CD-MOF时,加工结束时中式培根的过氧化值降低了17.8%,丙二醛含量降低了17.2%。     

恩施土家烟熏腊肉挥发性成分提取

以恩施土家烟熏腊肉为研究对象，分别采用索氏提取法、水蒸气蒸馏法、同时蒸馏萃取法和顶空固相微萃取法提取其挥发性物质，结合GC-MS技术对挥发性物质进行了定性定量分析与检测，并对比了各提取方法对挥发性物质分布与含量的影响。结果表明：在4种提取方法中烟熏腊肉挥发性物质种类分别为83种、53种、79种和62种，其中相同的挥发性物质有22种。这些挥发性物质分别为烃类、醇类、酚类、醛类、酸类、酯类、醚类及其他含硫含氮杂环化合物；各挥发性物质含量较大的为经顶空固相微萃取法提取得到的苯酚，为42016.73 ng/g。通过各挥发性物质的香气活度值(OAV)分析发现，对烟熏腊肉风味有贡献的主要风味物质59种，其中香气活度值较突出的为经顶空固相微萃取法提取得到的愈创木酚，高达10934。对比各提取方法结果发现，虽然不同提取方法各有优缺点，可以相互补充；但是通过顶空固相微萃取法得到的大部分挥发性物质相对含量比其他方法要高。同时对挥发物质进行了风味总结和嗅闻分析。     

腊肉产业存在的问题及应对措施

腊肉作为中国饮食文化中的瑰宝, 在肉制品的组成中占有重要的地位。近年来学者们对腊肉的研究大多集中于如何提高其发色效果、抑菌能力、风味增强和氧化稳定性以及各种腌制、熏制等新式工艺设备的研发, 目的在于更好地推进腊肉的工业化和现代化, 提高品质, 促进腊肉经济的发展。发现并解决腊肉存在的问题是提高其品质的必然途径。深入探究腊肉存在的主要问题并研究其应对措施, 对其高品质的形成具有重要意义。本文分析了腊肉存在的亚硝酸盐残留量高、脂肪氧化严重、生产工艺相对落后、食用麻烦以及含有苯并芘等问题, 并综述了其应对措施, 以期为腊肉的加工、贮藏及新品开发提供借鉴。     

老腊肉腌制烟熏加工过程中主体特征风味及变化规律

以重庆城口改进型老腊肉为研究对象,采用顶空固相微萃取结合气相色谱-质谱（gas chromatography-massspectrometry,GC-MS）联用技术,分析加工过程中挥发性风味物质的变化,并根据主体风味物质的变化规律确定最佳烟熏时间。分别对腌制前、腌制后、电热烘烤、烟熏5、10、15 d共6 个阶段的样品进行GC-MS分析。结果表明：6 个阶段检出的挥发性风味物质共80 种,其中醇类9 种、醛类17 种、酮类4 种、酚类10 种、酯类13 种、酸类1 种、醚类2 种、碳氢类化合物22 种、其他类2 种。通过对挥发性风味物质的定性、定量分析确定醛类、酚类、酯类和碳氢化合物为腊肉加工过程中的主体风味物质,并根据其种类和相对含量的变化规律确定了最佳的低温烟熏时间为10 d。     

黔式腊肉加工过程中理化成分与风味物质分析

以黔式腊肉为研究对象,对其加工过程中理化成分变化以及风味物质成分进行研究。结果表明：黔式腊肉加工过程中水分含量由70.75%下降到45.06%,酸价由0.84 mg KOH/g增加到2.31 mg KOH/g,过氧化值由0.48 meq/kg增加到2.00 meq/kg,pH值由6.03下降到5.80,脂肪不断水解、氧化生成小分子脂肪酸;非蛋白氮和挥发性盐基氮含量呈上升趋势;游离氨基酸总含量由441.55 mg/100 g增加到1 060.79 mg/100 g,其中,半胱氨酸增幅最大（112.17 mg/100 g）,其次是丙氨酸（94.79 mg/100 g）、亮氨酸（94.15 mg/100 g）、谷氨酸（89.67 mg/100 g）和苯丙氨酸（60.68 mg/100 g）。黔式腊肉中共鉴定出55 种挥发性风味物质,主体风味物质为酚类、羰基类、醇类、酯类和烃类。