Monitoring sausage fermentation using an electronic nose

In this study a sensor array and pattern recognition routines (an electronic nose) were used to monitor a sausage fermentation in order to follow the changes in emitted volatile compounds during the fermentation process and to compare the electronic nose results with a sensory analysis. From the sensor array responses the fermentation time could be predicted using different methods, where principal component regression and an artificial neural network based on all sensors in the electronic nose performed best. A sensory panel evaluated the final product and these results were compared with the electronic nose measurements in the early stage of the process and on the final sausages. A principal component analysis showed that one of the sausage batches clearly deviated from the other using both the sensory panel data and the electronic nose responses. The deviating batch was different already after 4 h and the difference was consistent during the process. © 1998 SCI.     

基于电子鼻技术研究保鲜方法对鲜切菠萝贮藏品质的影响

采用三种保鲜方式对鲜切菠萝进行处理（有机酸处理、漂烫处理、酸+漂烫综合处理）,通过电子鼻技术结合感官分析对鲜切菠萝的贮藏品质变化进行研究。感官评价结果表明:不同保鲜处理的效果从菠萝贮藏中期（3⁵d）开始出现差异性（p<0.05）,酸结合漂烫处理在贮藏中后期（3⁷d）分值较高,即酸结合漂烫处理能够更好的保持鲜切菠萝的贮藏品质;香气损失的线性判别分析（LDA）分析表明,酸结合漂烫处理能够有效延缓菠萝香气的损失;传感器贡献率分析（LA）表明,酸结合漂烫处理与对照组菠萝香气主要成分最为接近。总体来看,电子鼻分析结果与感官分析的结果基本一致,即电子鼻可用于快速评价菠萝贮藏品质;酸结合漂烫处理能够较好的保持菠萝原有特征香气及贮藏品质。      

基于电子鼻分析夏橙汁在贮藏过程中香气的变化

目的:研究了夏橙汁在不同贮藏温度和不同贮藏时间情况下橙汁的香气的变化情况。方法:电子鼻采集到夏橙汁的香气成分,并得到电子鼻传感器的响应值。利用PCA与DFA分析方法鉴别出夏橙汁在贮藏过程中香气的变化,以及在不同贮藏温度香气变化。结果:DFA的区分效果优于PCA的区分效果;在-18℃与4℃的低温贮藏条件下,橙汁的香气变化幅度较小,25℃贮藏的条件下香气成分的损失较多,并且三种贮藏温度下,第一、二周香气的响应值变化显著,第三、四周香气的响应值变化小,响应值接近。      

Effects of cold storage on aroma compounds of white- and yellow-fleshed peaches

The stir bar sorptive extraction (SBSE) technique was used to determine volatile constituents in two peach cultivars, one yellow-fleshed (cv. Spring Lady) and one white-fleshed (cv. Regina Bianca). For both cultivars four distinct experimental samples were considered, each formed by fruits obtained with four different cultivation practices. In order to investigate the effects of cold storage on the volatile profile, on all peach experimental samples changes in aroma compounds after 1 and 2 weeks of storage at 1°C, plus 1 day at ambient temperature, were monitored; moreover, only on the four experimental samples from cv. Regina Bianca, the effect of a prestorage hot water treatment (46°C for 25 min) was also evaluated. On the isolate obtained by SBSE, 24 compounds were identified and quantified by GC-MS: saturated and unsaturated lactones, aldehydes, C₁₃ norisoprenoids, monoterpenes, alcohols and esters. The profile of the white-fleshed cultivar was characterised by a higher level of C₁₃ norisoprenoids, and, in particular, of 8,9-dehydrotheaspirone. In all experimental samples after 1 week of storage, plus 1 day at ambient temperature, a marked increase (on average by 89%) in total lactones was observed. This increase was due to a noticeable accumulation of saturated lactones with longer side chains (γ- and δ-decalactone) and unsaturated lactones ((Z)-dec-7-en-5-olide and γ-jasmolactone). Peaches analysed after 2 weeks of storage showed total lactone levels close to those detected in the samples at harvest, suggesting that increasing storage times reduced fruit ability to accumulate these character impact compounds of peach aroma. A similar effect of cold storage, although less marked, was also observed on C₁₃ norisoprenoid fraction, but only on cv. Regina Bianca. On the other hand, we did not find univocal effects of cold storage on C₆ aldehydes, whereas linalool, detected only in samples of cv. Spring Lady at harvest, disappeared quickly during the first days of storage. In samples of cv. Regina Bianca peaches subjected to hot water treatment, after 1 week of storage, lactone level was significantly reduced in comparison with untreated fruits, denoting a possible inhibition effect on lactone accumulation and on aroma development.     

不同压力处理大米制得米饭冷藏期间风味变化的电子鼻分析

采用电子鼻测定了不同压力处理大米制得米饭冷藏期间的挥发性成分,探讨电子鼻用于检测米饭风味成分、区分不同冷藏时间米饭的可行性及超高压处理对米饭冷藏期间风味变化情况的影响。大米在温度40℃、米水比(w/w)为1∶2的条件下浸泡40min,并在15℃下分别经200、400、600MPa处理10min,以未经超高压处理的大米作为对照组,将其蒸煮15min制成米饭,保鲜膜密封后置于4℃下贮藏,冷藏期间每天采用PEN3电子鼻对米饭进行测定。采用主成分分析法(PCA)、传感器贡献率分析法(LA)、线性判别式分析法(LDA)分析了米饭冷藏期间的挥发性成分,并建立了特征雷达图。结果表明:压力对米饭冷藏期间甲烷、硫化物、乙醇、芳香类及有机硫化物的产生有较大影响,贮藏期间200MPa米饭甲烷、硫化物、乙醇的产生量最高,600MPa米饭硫化物、芳香类及有机硫化物的产生量最低;W5S、W1W是识别米饭挥发性成分的主要传感器;电子鼻对米饭的挥发性物质反应比较灵敏,可用于米饭挥发性物质的无损检测;PCA分析可区分不同贮藏天数的对照或600MPa米饭,LDA分析可区分不同贮藏天数的400MPa或600MPa米饭。      

1-MCP处理对甜柿贮藏品质的影响和电子鼻分析

在常温货架期、低温贮藏期和贮后货架期,研究不同处理对甜柿贮藏品质的影响,并利用电子鼻对不同处理甜柿挥发性成分进行判别分析。结果表明,LDA方法有效区分不同常温货架期和贮后货架期的甜柿,对低温贮藏期间的甜柿区分效果稍差。1-MCP处理可以延缓果皮L*和b*、果实质地（果皮强度、果皮脆性和果肉平均硬度）的下降,在贮后货架期间作用效果更为明显。在常温货架期和低温贮藏期,1-MCP处理组和对照组甜柿挥发性成分差异较小,在贮后货架期间差异较大,电子鼻可以有效区分贮后货架期间1-MCP处理组和对照组。      

基于电子鼻评价不同贮藏期蜜桔鲜榨汁品质的研究

为建立一种快速无损检测蜜桔鲜榨汁品质的方法,将宫川蜜桔(satsuma mandarins)置于20℃、相对湿度85%条件下贮藏,每3 d随机选取10个果实制成汁,利用PEN3电子鼻检测其香气,同时测定其主要品质指标并进行相关性分析。通过主成分分析(Principal Component Analysis,PCA)、线性判别分析(Linear Discriminant Analysis,LDA)对不同贮藏时间的蜜桔进行区分。结果显示:电子鼻传感器响应值与蜜桔鲜榨汁可溶性固形物含量和VC含量显著相关;线性判别分析能较好地区分出不同贮藏时间的蜜桔;负荷加载分析(Loading analysis)结果显示,传感器W1S(主要对甲烷灵敏)、W2S(对乙醇灵敏,也对部分芳香型化合物灵敏)和W2W(对芳香成分和有机硫化物灵敏)在蜜桔鲜榨汁品质评价中起主要作用。结果表明利用电子鼻技术有望实现对蜜桔鲜榨汁品质的快速无损检测。      

鲜切芋艿冷藏期间生理及品质变化

以山东威海产芋艿为材料,以整芋为对照,研究了4℃冷藏条件下鲜切芋艿的色差(L*、a*、b*)值、还原糖和抗坏血酸含量、呼吸率、丙二醛、淀粉等指标的变化。结果表明:冷藏期间鲜切芋艿色泽的变化明显,可通过L*、a*、b*值来反映,L*在冷藏期明显下降,a*和b*呈上升势态;同时,切分后的芋艿呼吸强度和丙二醛含量增加;抗坏血酸、还原糖和淀粉等较整芋艿损失多。     

Use of electronic nose and trained sensory panel in the evaluation of tomato quality

In this paper the performances of an electronic nose based on metalloporphyrin‐coated quartz microbalance sensors and of an experienced panel of seven human assessors in the evaluation of gases derived from degradation reactions in tomatoes are presented and discussed. The performances are measured in terms of the capability of both systems to distinguish between samples of different quality coming from conventional and organic production systems. The study deals with the application of pattern recognition techniques based on either multivariate statistical methods (PCA, GPA) or artificial neural networks using a self‐organising map (SOM). The response pattern of the sensor array and the sensory data are analysed and compared using these methods. Similarities in the classification of the data by electronic nose and human sensory profiling are found. © 2000 Society of Chemical Industry     

低温等离子体对蓝圆鲹在冷藏过程中的品质影响

目的 研究低温等离子体(atmospheric cold plasma, ACP)对蓝圆鲹在冷藏过程中品质变化的影响。方法 以蓝圆鲹为研究对象,采用介质阻挡放电低温等离子体设备对其进行处理(处理组),新鲜蓝圆鲹为对照组,4℃±1℃的条件下分别贮藏0、2、4、6、8、10 d,通过样品pH、持水力(water holding capacity, WHC)、菌落总数、挥发性盐基氮(total volatile basic nitrogen, TVB-N)、硫代巴比妥酸(thiobarbituric acid, TBARS)值、组胺含量、感官评价等指标来分析蓝圆鲹在冷藏期间的品质变化。结果 随着贮藏时间的延长,两组样品pH呈先下降后上升的趋势;菌落总数由初始值2.97 lg(CFU/g)和3.00 lg(CFU/g)分别上升到6.10 lg(CFU/g)和6.72 lg(CFU/g),处理组菌落总数上升速度较缓;TVB-N值和组胺含量均呈上升的趋势,且随着贮藏时间的延长,对照组比处理组上升速度更为明显;持水力和感官评分随着贮藏时间的延长而明显下降;TBARS值随着贮藏时间的延长而增加,且处理组的TBARS值始终高于对照组。结论 低温等离子体处理能够有效地保持蓝圆鲹的鲜度,尤其是在抑制微生物的增殖方面有较大优势,能够延长蓝圆鲹的货架期至少2 d。本研究为延长蓝圆鲹的货架期提供了一定的理论基础。     

相变蓄冷材料及其在冷库中应用的研究进展

采用文献综述及实际案例相结合的方法,分析了相变材料的特点、蓄冷冷库制冷的原理,以及在实际应用中如何充分发挥各自的优点以达到理想的效果.     

超高压处理白切鸡在冷藏过程中微生物和品质的变化

超高压(487 MPa,17 min,26 ℃)处理后,白切鸡在4 ℃保藏过程中的微生物和品质变化结果显示,在保藏60 d时,白切鸡中的微生物总量达国家卫生标准规定值,70 d时完全腐败,其中假单孢菌为优势腐败菌属,其次为肠杆菌属和乳酸菌属.高压处理后白切鸡在保质期内的感官品质较好,保藏过程中的TBA值和TVB-N值呈显著增大的趋势,硬度和pH在保藏前期的变化不显著,后期显著下降,色泽L*值、a*值和弹性等变化均不显著.相关性分析结果表明,样品细菌总数项与硬度显著负相关,与TVB-N值显著正相关;感官评分与TVB-N值显著负相关.     

Relationship between the physicochemical parameters and the ethylene emission during cold storage of kiwifruits

Kiwifruit production is a dynamic agricultural activity in Corsica and represents 10% of the French total. Because of its composition, sensory characteristics and resistance during preservation, the kiwifruit has great potential for industrial exploitation. The kiwifruit (Actinidia deliciosa cv. Hayward) produces ethylene because it is a climacteric fruit. The concentration of ethylene increases during cold storage at 0 °C. This increase is slow in the first 2 months of storage and then accelerates quickly to reach the climacteric peak. The timing of this climacteric peak varies in function of the year of harvest, occurring after between 100 and 140 days of storage. In parallel with this ethylene production, there is an increase in reducing sugar concentration, Brix, acidity and Botrytis cinerea contamination and conversely a reduction in the firmness and mass of the fruits. This study used statistical analysis to summarise these changes and show the influence of ethylene on the ripening and storage time of the kiwifruits.     

两种贮藏温度对鲤鱼肉感官品质影响的差异性分析

以淡水鲤鱼为研究对象,研究两种贮藏温度对鲤鱼肉感官品质的影响。采用色差、电子鼻与质构并结合感官评定分析,探讨鲤鱼肉在冰温贮藏（-2℃）与冷藏（4℃）的两种贮藏温度条件下感官品质变化的差异。结果表明:-2℃下鲤鱼的感官分值明显优于4℃,前者在贮藏12 d时感官评分仍保持在18分以上,新鲜度良好,后者则在第8 d后迅速降至13分,失去其食用与商业价值;两组贮藏温度下的鱼肉颜色与贮藏时间显著相关,其中-2℃的鱼肉样品颜色变化更为缓慢;电子鼻分析结果得出,Linear Discriminant Analysis（LDA）分析较Principal Component Analysis（PCA）分析能更好反映冰温和冷藏条件下鲤鱼肉挥发性物质的变化情况;冰温和冷藏条件下样品的弹性指标与贮藏天数均显著相关（p<0.05）,说明贮藏时间对鱼肉的弹性影响较大。综合来看,-2℃贮藏的鱼肉在感官品质,色泽与挥发性成分的变化上优于4℃,在鱼肉硬度与弹性变化上,-2℃的样品变化更为平缓;在粘聚性,胶着度与咀嚼度方面,-2℃与4℃的差别较小。      

Effect of sulphiting and drying methods on physico-chemical and sensorial quality of dried apricots during ambient storage

Fresh mature and ripe apricots after preparations were pre-treated with potassium meta-bisulphite (KMS) at concentrations of 2–8% for 30, 45 and 60 min followed by drying in solar tunnel dryer and in open air. After completion of drying, the samples were packed in polyethylene pouches and evaluated for various quality parameters at 0, 6 and 12 months of ambient storage. KMS pre-treatment at concentration of 6% for 60 min prior to drying helped significantly in improving and maintaining the quality of dried apricots for up to 12 months of ambient storage. Solar tunnel drying resulted in hygienic product and reduced the drying time to 3–4 days compared with 14–16 days in open air drying. Residual free sulphur dioxide of apricots pre-treated at KMS concentration of 6% for 60 min was within the prescribed limits of the Fruit Product Order (1955) specifications for dried products.     

不同涂膜保鲜剂对蒙自甜石榴冷藏品质的影响

目的探讨羧甲基纤维素钠(CMC)、海藻酸钠、魔芋和果胶4种涂膜保鲜剂对冷藏石榴品质的影响。方法以蒙自"甜绿籽"石榴为试验材料,涂膜处理后,在(5±1)℃低温冷藏,测定石榴籽粒中可溶性固形物、总糖、总酸、维生素C和腐烂率等指标随冷藏时间的变化。结果果胶涂膜处理能显著延缓贮藏期间可溶性固形物、总糖、总酸含量的下降,提高冷藏期间石榴的营养品质,效果优于其他涂膜保鲜剂;CMC涂膜处理能显著降低石榴的腐烂率,可延缓维生素C和可溶性固形物的损失;海藻酸钠涂膜处理可延缓可溶性固形物含量的降低,但是对维生素C、总糖、总酸和腐烂率无显著效果;魔芋涂膜处理能延缓总糖、总酸含量的下降,但是使腐烂率显著升高。结论果胶和CMC涂膜处理对冷藏石榴均有良好的保鲜效果。     

不同烟熏液处理对罗非鱼片冷藏品质的影响

将罗非鱼片进行浸渍(A组)和涂抹(B组)烟熏液处理,置于0℃条件下冷藏,对罗非鱼片在贮藏过程中的pH、TVB-N值、TBA值、白度值进行分析,以及进行感官评价。结果表明,经烟熏液处理的罗非鱼片具有烟熏色泽和烟熏风味,且能防止脂肪氧化,延长鱼片的保藏期。相较于B组鱼片,A组鱼片的pH、TVB-N值、TBA值、白度值变化更稳定,其中TVB-N值在第21d为19.2mg/100g,保藏期可达21d。     

骨蛋白水解物对冷藏鱼糜品质和蛋白结构特性的影响

通过测定不同贮藏时间内（0、1、3、5、7d）鲤鱼鱼糜的颜色（白度值、亮度值）、硫代巴比妥酸值、挥发盐基氮,及肌原纤维蛋白的ATPase酶活性、表面疏水性、总巯基含量等指标的变化,研究冷藏（4℃）条件下骨蛋白水解物对鲤鱼鱼糜的抗氧化效果及对蛋白的保护作用。结果表明,随着骨蛋白水解物添加量的增加,鱼糜色泽明显改善,鱼糜样品的TBRAS、TVB-N及表面疏水性呈下降趋势;而Ca2+-ATPase酶活性、总巯基含量呈上升趋势。其中添加7%骨蛋白水解物的样品效果最为明显,冷藏至第7d时,与对照组相比,样品的TVB-N及表面疏水性分别降低了1.30g/100g、1.80μg,且效果显著（p<0.05）。因此,骨蛋白水解物能够抑制淡水鱼鱼糜的蛋白和脂肪氧化变性,且浓度越高效果越明显。      

充气包装对青菜冷藏品质的影响

充气包装已成为一种有效的延长小包装蔬菜货架期的保鲜技术。目的是选择最合适的环境气调贮藏包装青菜,研究贮藏在4℃,不同的气体浓度(空气对照组、10%CO2+20%O2+70%N2、10%CO2+5%O2+85%N2、10%CO2+1%O2+89%N2、5%CO2+5%O2+90%N2、15%CO2+10%O2+85%N2)对其感官品质、叶绿素、亚硝酸盐、可溶性固形物、电导率等指标的影响。结果表明:4℃下,延长青菜货架期和保持其营养品质的最佳的气体组成为10%CO2+5%O2+85%N2。