基于形态学特征的对虾完整性识别方法构建

目的 针对对虾加工过程中缺损对虾混入完整对虾从而降低对虾产品外观品质的问题, 构建基于形态学特征的对虾完整性识别方法。方法 首先, 使用灰度差异法处理对虾图像, 经过连通域、中值滤波等形态学操作后, 得到较为完整的感兴趣区域图像, 再对其采取二值化、轮廓化等操作; 然后, 对轮廓提取骨架线, 并求轮廓内最大内切圆直径以得到长宽比特征, 并求其圆度特征; 最后, 将以上2个特征作为判别对虾完整性的核心指标, 构建融合特征判别算法。结果 本研究所提算法应用于1063幅生鲜虾测试集图像中识别准确率达到99.25%, 相比于传统曲率法, 识别准确率提升了6.48%, 识别时间降低了1598.6 ms。结论 该方法具有较大优势和应用前景, 为开发大规模南美白对虾在线品质的无损检测装备提供关键技术。     

基于高光谱图像信息的李果实成熟度判别

本文以李果实作为研究对象,基于高光谱图像技术对不同成熟度的李果实(未熟、半熟、成熟和过熟)样本的图像信息进行采集,对采集样本的图像进行中值滤波去噪处理。运用Matlab软件编程对各种成熟度样本的图像进行颜色特征值提取,分别获得RGB和HSV彩色图像模型不同分量的平均值(μ)和标准差(σ)作为颜色特征值,并建立RGB、HSV颜色特征值以及RGB-HSV特征值相融合的样本成熟度PLS判别模型,并对所建立的判别模型进行预测。结果表明,基于RGB-HSV相融合颜色特征值的判别模型准确率优于RGB与HSV,其对未熟、半熟、成熟、过熟的判别准确率达到了98.4%、90.0%、85.6%及90.9%。该方法建立的判别模型不仅简化,而且增强了模型的判别能力,为实现李果实成熟度的无损检测和判别提供理论依据。     

基于机器视觉的淡水鱼去鳞损伤无损检测识别方法

为了研究淡水鱼去鳞损伤无损检识别方法,以鲤鱼为研究对象,搭建视觉采集系统,实现图像采集与处理。通过采集鲤鱼去鳞后有去鳞损伤的图像,将样本图像划分为鱼腹、鱼背、鱼尾、损伤、背景五部分,提取感兴趣区域(ROI),比较其颜色差异,发现正常鱼体的表面区域与损伤区域颜色差异较大,以不同区域对应的红色通道值(R)、绿色通道值(G)、蓝色通道值(B)对应像素的平均值作为输入,建立基于广义神经网络(GRNN)和径向基函数神经网络(RBF)的鱼体损伤区域检测识别模型,经测试,识别准确率分别能达到98%和80%。通过计算预测损伤区域与实际损伤区域的相关面积大小,验证识别模型的准确度,经试验验证,基于GRNN和RBF网络识别模型对去鳞损伤预测的准确率分别达到了90%和83%。研究结果表明,机器视觉可应用于淡水鱼去鳞损伤的无损检测识别。     

常压油炸与空气油炸对凡纳滨对虾中虾青素含量及抗氧化活性的影响

目的：对比研究常压油炸与空气油炸对凡纳滨对虾虾青素含量以及抗氧化活性的影响。方法：利用有机溶剂提取法提取虾青素，高效液相色谱法测定虾青素含量，以1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl，DPPH）自由基、2,2’-联氮-双-(3-乙基苯并噻唑啉-6-磺酸)（2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)，ABTS）阳离子自由基和羟自由基清除率为指标分析常压油炸与空气油炸虾青素提取物的体外抗氧化活性。结果：两种加热方法对凡纳滨对虾的影响不同，加热后对虾的颜色变化与虾青素含量有关，在空气油炸过程中，凡纳滨对虾虾肉的虾青素含量呈先增大后减小的趋势，抗氧化活性呈逐渐上升至平稳的趋势。200 ℃空气油炸240 s时对虾的虾青素含量以及抗氧化活性增加最明显，常压油炸加热使虾青素含量以及抗氧化活性损失严重，随着加热时间的延长不断下降。结论：空气油炸对虾青素含量及体外抗氧化活性的影响比常压油炸小。     

基于机器视觉的番茄成熟度颜色判别

提出一种颜色分析方法用于新鲜番茄分类,以GB 8852—88标准为参考,定义番茄成熟度的分类标准(在研究中将其分成四类:完熟、成熟、半熟、绿熟),将采集到的番茄RGB图像,去除背景后,滤波去噪,转换成HIS颜色模型和HSV颜色模型。通过Matlab编程获取R、G、B、H、S、V、I各颜色分量的均值,运用SPSS软件进行判别筛选组合特征分量,运用Matlab进行判别分析。分析结果显示,绿熟番茄在3种不同判别函数下训练集与验证集判别率均达到了100.00%;半熟番茄训练集判别率最高为94.74%,同时验证集判别率最高达到100%;成熟番茄训练集与验证集判别率最低,分别为76.67%和70.00%;完熟番茄训练集与验证集最高均为90.00%。总体上实现了不同成熟度番茄的判别分类。     

基于电子鼻技术判别南美白对虾鲜度模型的建立

以南美白对虾为研究对象,结合感官评定和挥发性盐基氮测定,对5℃贮藏条件下的虾样品进行电子鼻测定,建立基于电子鼻技术的虾鲜度判别模型。结果显示:通过模型判别的正确率确定了数据归一化方法。通过主成分分析,提取了使得累计方差贡献率达到86.974%的前3个主成分,利用所得主成分进行fisher线性判别。得到的判别模型对建模样本数据和模型验证样本数据的判别正确率分别为98.3%和91.7%。说明运用主成分分析-fisher线性判别模型可以对虾鲜度进行判别,所建模型的判别正确率高,模型稳定。     

对虾虾头中磷脂提取工艺的研究

为充分利用对虾加工副产物资源,采用溶剂提取法,探讨以对虾虾头为原料提取磷脂的最佳工艺和影响因素。以磷脂纯度为指标,通过单因素实验与正交实验,考察料液比、乙醇体积分数、提取时间及提取次数对磷脂提取的影响,制定出虾头磷脂的最佳提取工艺。结果表明,虾头磷脂的最佳提取工艺条件为:料液比1∶6,采用90%乙醇溶液作为提取液提取虾头2次,每次提取6 h。在最佳提取工艺条件下,虾头提取物中磷脂纯度为45.81%。该提取工艺简单、污染少、提取效率高,为低附加值海产品加工副产物的高值化利用提供有效途径。     

基于计算机视觉的核桃外观缺陷检测

为快速准确识别核桃外观缺陷(黑斑、破裂),自行搭建图像采集系统采集样本图像。预处理后采用形态学和逻辑运算去除背景,基于样本图像提取18个颜色特征参数和20个纹理特征参数。采用形态学和逻辑运算提取缺陷部分和样本投影像素面积的比值t以及样本图像阈值分割后二值图像的欧拉数。分别采用回归系数法(Regression Coefficient,RC)和连续投影法(Successive Projections Algorithm,SPA)优选特征参数并建立偏最小二乘法(PLS)模型。结果表明,基于SPA法优选特征参数建立的模型性能最优。将SPA法提取的5个优选特征参数作为输入建立最小二乘支持向量机(LS-SVM)模型,并对预测集样本进行预测。结果表明,对正常核桃、黑斑核桃、破裂核桃的判别准确率分别为88.9%、83.3%、94.6%,总判别率为88.9%。本研究建立的方法能够很好的对核桃外观缺陷进行检测,为今后核桃的在线检测分选提供了技术支持。     

基于高压结合酶法制备的低敏虾制品体内体外致敏性检测的差异性分析

采用高压结合酶法处理凡纳滨对虾的虾蛋白、虾仁泥（虾肉）和虾仁,获得3 种低敏虾制品;采用酶联免疫吸附法检测3 种虾制品的过敏原性,采用全身性过敏反应（过敏性休克模型）及致敏离体回肠平滑肌收缩实验（Schultz-Dale反应）检测3 种低敏虾制品的致敏性,以分析体内与体外方法检测虾制品致敏性的差异性。结果显示：处理前的3 种原料过敏原性极高。经高压结合酶法处理的虾蛋白、虾肉和虾仁的过敏原性分别消减97.0%、94.1%和94.5%。而在动物实验中（以磷酸缓冲盐溶液为阴性对照,未处理虾蛋白为阳性对照,以豚鼠为受试对象）,未处理虾蛋白组的过敏反应发生率与死亡率均为100%,3 种低敏虾制品的过敏反应发生率也为100%,死亡率分别为16.7%（虾蛋白产物）、50%（虾肉产物）和83.3%（虾仁产物）。致敏的离体回肠受到3 种低敏虾制品攻击后,收缩力也明显增强,分别达到376.9%、766.2%和1 004.4%。上述结果表明,对高压结合酶法制备的低敏虾制品过敏原性的检测,体外检测与体内检测存在一定的差异性。     

基于图像处理和神经网络的小麦不完善粒识别方法研究

为了实现图像处理技术对小麦不完善粒的准确快速识别,研究了一种基于小麦不完善粒图像特征和BP神经网络的不完善粒识别方法。采集小麦不完善粒图像,对图像进行中值滤波、形态学运算、图像分割等处理后,针对每个小麦籽粒,提取其形态、颜色和纹理共3大类54个特征参数,采用主成分分析法提取8个主成分得分向量作为模式识别的输入,建立BP神经网络模型,实现对小麦不完善粒的检测识别。结果表明,该模型对完善粒、破损粒、病斑粒、生芽粒和虫蚀粒的判别正确率分别为93%、98%、100%、90%和85%,平均判别正确率达到93%,可有效对小麦不完善粒进行检测识别。     

盐藻多糖对熟制南美白对虾冻藏期间品质变化的影响

研究了0.06%盐藻多糖处理对冻藏南美白对虾品质的影响。以菌落总数、TVB-N值、TBA值、色差(L~*、a~*和b~*)、质构(硬度和弹性)和水分含量作为评价指标,分析盐藻多糖处理对冻藏对虾新鲜度和品质的影响。结果表明,熟制南美白对虾冻藏期间新鲜度没有超标,但虾体水分含量降低幅度较大,硬度迅速增加,弹性降低,L~*、a~*和b~*值降低,对虾整体品质随着贮藏时间的增加而下降。盐藻多糖处理提高了对虾的新鲜度,且保持了虾体水分,改善了对虾的硬度和弹性,抑制了对虾褪色,起到了一定的保水和护色作用。     

南美白对虾冰温气调保鲜效果评价

将鲜南美白对虾进行空气包装(AP)、真空包装(VP)、气调包装(MAP,75% CO2/25% N2),分别冰温(－2.3～0℃)贮藏和冰藏,通过研究样品贮藏过程中多酚氧化酶(PPO)活力、总挥发性盐基氮(TVB-N)、菌落总数(TPC)、汁液流失率(DL)的变化,结合感官指标评价冰温气调保鲜的效果。结果表明：南美白对虾的PPO活力变化与腐败变质同步;冰温结合MAP能有效防止褐变,货架期可达10d,比冰藏结合AP延长了约3倍,此时样品色泽良好,TPC、TVB-N、DL分别为5.4(lg(CFU/g))、25.6mg/100g、3.13%,而其他包装样品已腐败。VP也能较好的保持色泽,但贮藏后期汁液流失相对严重,影响外观。     

Microbial quality of shrimp products of export trade produced from aquacultured shrimp

Bacteriological quality of individually quick frozen (IQF) shrimp products produced from aquacultured tiger shrimp (Penaeus monodon) has been analysed in terms of aerobic plate count (APC), coliforms, Escherichia coli, coagulase-positive staphylococci, Salmonella, and Listeria monocytogenes. Eight hundred forty-six samples of raw, peeled, and deveined tail-on (RPTO), 928 samples of cooked, peeled, and deveined tail-on (CPTO), 295 samples of headless, undeveined shell-on (HLSO), and 141 samples of raw, peeled, and deveined tail-off (RPND) shrimps were analysed for the above bacteriological parameters. Salmonella was isolated in only one sample of raw, peeled tail-on. Serotyping of the strain revealed that it was S. typhimurium. While none of the cooked, peeled tail-on shrimp samples exceeded the aerobic plate count (APC) of 10(5) colony forming units per gram (cfu/g), 2.5% of raw, peeled, tail-on, 6.4% of raw, peeled tail-off, and 7.5% of headless shell-on shrimp samples exceeded that level. Coliforms were detected in all the products, though at a low level. Prevalence of coliforms was higher in headless shell-on (26%) shrimps followed by raw, peeled, and deveined tail-off (19%), raw, peeled tail-on (10%), and cooked, peeled tail-on (3.8%) shrimps. While none of the cooked, peeled tail-on shrimp samples were positive for coagulase-positive staphylococci and E. coli, 0.6-1.3% of the raw, peeled tail-on were positive for staphylococci and E. coli, respectively. Prevalence of staphylococci was highest in raw, peeled tail-off (5%) shrimps and the highest prevalence of E. coli (4.8%) was noticed in headless shell-on shrimps. L. monocytogenes was not detected in any of the cooked, peeled tail-on shrimps. Overall results revealed that the plant under investigation had exerted good process control in order to maintain superior bacteriological quality of their products.     

蒸烤模式对南美白对虾食用品质的影响

以南美白对虾为研究对象,以色差值、质构品质、游离氨基酸含量及感官评分为指标,通过色彩色差计、物性测试仪、氨基酸专用高效液相色谱仪以及感官评价法考察不同蒸烤模式（纯蒸、纯烤、先蒸后烤、先烤后蒸、蒸烤交替）对虾肉食用品质的影响。结果表明：先烤后蒸模式下虾皮和虾肉的L*值显著低于其他4 种模式（P＜0.05）;纯烤模式下虾的硬度和咀嚼性均显著高于其他4 种加热模式（P＜0.05）;游离氨基酸含量分析结果显示,纯蒸模式下虾的游离氨基酸总量最多,蒸烤交替模式下甜味氨基酸比例最高、苦味氨基酸比例最低。最后综合感官评定结果得出,在南美白对虾的不同蒸烤模式中,纯蒸和蒸烤交替模式优于其他3 种加热模式。     

The potential of ohmic heating as an alternative to steam for heat processing shrimps

The potential application of Ohmic Heating as an alternative to the conventional steam cooking for shrimps is examined in this study. Defrosted unpeeled shrimps (Pandalus borealis) were cooked either in a steamer or ohmically up to a 72 °C core-temperature. The head, body and tail of steam-heated shrimps cooked at different rates whereas the OH treatment was more uniform and faster. The impact of shrimp size on heating rate was also evaluated, with an overall cooking time of 38 s and 59 s for steam-cooked small and large shrimps, respectively, while only 40 s where needed for OH regardless of shrimp size and measured anatomical location. No differences were found for cook loss and texture (WBSF and Kramer methods) between cooking methods. However, shrimp size seemed to determine the effect of OH on colour differences (ΔE), with greater differences observed in large vs. small shrimps, although overall ohmically-cooked shrimps showed less colour differences compared to those cooked conventionally with steam.Industrial relevanceTraditional heating processes such as boiling or steaming are used in industrial cooking of shrimps. However, the low rate of heat penetration to the thermal centre of shrimps leads to heterogeneous treatments resulting in overcooking which may reduce yield. Ohmic heating technology offers a potential alternative over conventional heat treatments as heat is generated volumetrically inside the food. This form of heat generation results in more uniform temperature distribution which leads to shorter processing times and potentially higher yields while still maintaining the colour and nutritional value of food. This paper hence exploits the potential of Ohmic heating technology as an alternative to conventional steam processing for the cooking of shrimps.     

Preference ranking of colour in raw and cooked shrimps

The reddish colour to shrimp, which has been associated with its high quality, is one of the major factors for its acceptability by consumers. The aim of this work was to analyse consumer preference regarding colour in raw and cooked shrimps. Farmed shrimps Litopenaeus vannamei (13.8 + 1.16 g) were fed with control or supplemented food (60 ppm of carotenoids). The shrimp samples were analysed in naked eye, confirmed by colorimetry and sorted in the following categories: dark grey (L* 27.99; h 168.16), grey (L* 32.58; h 124.60), and light grey (L* 36.2; h 119.35) for raw shrimps; and intense orange (L* 61.49; h 54.69), orange (L* 65.97; h 57.79) and light orange (L* 72.65; h 70.17) for cooked shrimps. A preference ranking test was performed with 35 judges invited to rank the samples in descending order of preference. Consumers prefer lighter raw shrimp (light grey and grey) and brightly orange cooked shrimps (orange and intense orange), which indicates that supplementing shrimp food for pigmentation should be followed by improving its acceptance by consumer. These results indicate a challenge for the shrimp industry, as the lightest raw shrimps are also not so brightly orange coloured after cooking.     

海藻糖、海藻胶及寡糖对蒸煮南美白对虾的抗冻保水作用

为探索海藻糖类在冷冻熟制水产品中的应用效果,以蒸煮南美白对虾为研究对象,以焦磷酸钠为阳性对照,研究海藻糖、海藻胶及寡糖对蒸煮虾仁的抗冻、保水作用。结果表明：－18 ℃冻藏6 周后,1.0 g/100 mL海藻糖、海藻胶寡糖浸泡处理,显著降低了冷冻蒸煮虾仁解冻和蒸煮损失率（P＜0.05）,其与焦磷酸钠保水效果无显著性差异（P＞0.05）。在整个冻藏期内,0.5、1.0 g/100 mL海藻糖和海藻胶寡糖处理,虾仁肌肉a*值保持效果显著优于其他处理组（P＜0.05）,表明该2 种糖类对蒸煮虾仁色泽具有较好的保护。随着冻藏时间延长,不同处理组虾仁水分含量、水分活度和质构特性均呈逐渐下降趋势,其中以海藻糖、海藻胶寡糖处理对虾仁水分、质构特性保持效果较好,且显著优于蒸馏水和焦磷酸钠组（P＜0.05）。经组织结构观察发现,1.0 g/100 mL海藻胶寡糖处理虾仁,肌纤维排列致密、无扭曲变形,且肌肉中无较大间隙或孔洞产生,表明海藻胶寡糖具有抑制肌肉间隙冰晶生长、保护肌肉组织完整性的作用。结果可为开发一种安全、高效、适用于冷冻蒸煮虾仁的无磷保水剂提供参考。     

Effects of succinate on ground beef color and premature browning

The objective of this experiment was to determine the effects of succinate on raw and cooked ground beef color. Chubs (n=10) were divided in half and assigned to either succinate (final w/w concentration of 2.5%) or distilled water. Patties (n=14 per chub half) were assigned to initial day 0 color and each of 6 treatment combinations, created by crossing 3 packaging types (vacuum, high-oxygen/80% O(2), and PVC) with 2 storage times (days 1 and 3). After storage, patties were cooked to either 66 °C or 71 °C. Succinate increased (P<0.05) ground beef pH and metmyoglobin reducing activity but had no effect (P>0.05) on raw a* and chroma values. Moreover, succinate decreased (P<0.05) raw L* values, lipid oxidation, and premature browning for patties packaged in PVC and high-oxygen. Succinate may increase cooked patty redness via its influence on meat pH.