近红外漫反射光谱法快速测定秸秆青贮饲料成分含量

采用傅里叶近红外漫反射光谱技术,结合偏最小二乘回归法,以158个不同种类的秸秆青贮饲料样品建立了常规化学成分和发酵成分含量的近红外定量分析校正模型。其中常规化学成分中, 粗蛋白、中性洗涤纤维、酸性洗涤纤维、半纤维素、干物质、粗灰分和酸性洗涤木质素含量的校正模型决定系数R2分别为0.95,0.90,0.86,0.91,0.86,0.95和0.90;发酵成分的pH、乳酸、乙酸、丙酸、丁酸和氨态氮含量的校正模型决定系数R2分别为0.98,0.83,0.85,0.3,0.90和0.92。研究发现除乙酸、丙酸和丁酸之外,其他成分含量的相对分析误差RPD(SD/SECV)均大于2.5;除乳酸、乙酸、丙酸和丁酸之外,所建近红外定量分析模型对独立检验集样品其他成分含量的预测值与化学值的相关决定系数R2均大于0.08。该研究结果对青贮饲料品质的快速检测具有重要的实际意义。     

鸡粪工厂化堆肥主要营养成分含量近红外光谱分析研究

目前,堆肥化是解决畜禽粪便污染环境和造成社会经济问题、实现其无害化和资源化利用的简便易行的重要途径。鸡粪中含有大量的氮磷钾等营养成分。文章以鸡粪和菊花渣工厂化高温堆肥发酵过程氮、磷和钾主要营养成分为研究对象,探讨利用近红外光谱法进行无损速测分析的可行性。在鸡粪工厂化堆肥不同发酵阶段进行多点取样,利用美国Nicolet公司生产的傅里叶变换型近红外光谱仪采集在10 000～4 000 cm-1范围内原始样品光谱,并结合多种光谱数据处理方法和偏最小二乘回归法建立了总氮、总磷和总钾的近红外模型并进行了验证分析。根据环境类样品近红外模型评价标准,近红外光谱法测定鸡粪堆肥过程主要营养成分含量具有较好的可行性。其中,所建总氮含量模型验证决定系数(R2)大于0.80,验证相对分析误差(RPD)大于2.0; 所建总磷和总钾模型的R2和RPD值分别大于0.90和3.0。     

盐酸左西替利嗪片的近红外漫反射光谱定量分析

利用近红外光谱结合偏最小二乘法实现对不同品牌盐酸左西替利嗪片剂有效成分的定量分析。经内部交叉验证,确定最佳波数范围和光谱预处理方法,以及最佳主成分数,建立最优PLS校正模型。对验证集样品浓度进行预测,得到均方根误差RMSECV、决定系数R2分别为0.276和0.974。该方法能够用于不同厂家盐酸左西替利嗪片的快速定量分析,是一种有效的药品快速检验技术。     

一种测量动脉血氧饱和度的新方法

在传统的血氧饱和度测量方法中,首先计算对数光电容积脉搏波交、真流成分的比值(R值),然后通过实验建立血氧饱和度值与R值的线性回归模型,旨在消除光程的影响,将个体差异的影响降至最小化,是一种基于Lambert-Beer定律的降维处理。当考虑散射时,这种以交、直流成分的比值作为自变量的降维处理方式损失了信息量,引入了系统误差,限制了测量的精度。为了减小这种影响,从透射光电脉搏波所含信息量的角度,提出了使用双波长对数光电容积脉搏波的峰值和谷值作为自变量与血氧饱和度值建立线性回归模型的新方法。从23名健康志愿者中获得133例光电脉搏波及血氧饱和度参考值样本,从中随机抽取90例作为建模集,另外43例作为预测集,对比了新方法和R值法的建模和预测结果。随机抽取建模集并预测10次,新方法和R值法的平均预测相关系数分别为0.890 6和0.846 8,平均预测均方根误差分别为0.889 6%和1.037 3%,结果表明新方法的预测效果优于传统R值法,使用四个特征量建立血氧饱和度预测模型,能够提高测量的稳定性和精度,对基于有限波长光谱数据建模测量人体血液生理参数有指导意义。     

近红外漫反射光谱法测定玉米秸秆体外干物质消化率

以不同生态环境、不同年份,不同品种和自交系类型、不同生长发育时期以及不同部位的600个样品中选出161份玉米秸秆为材料,应用傅里叶变换近红外光谱技术,采用偏最小二乘回归法(PLS),通过比较不同光谱范围和光谱预处理方法,在6 101.7～5 773.8 cm-1和4 601.3～4 246.5 cm-1谱区内,建立了适合不同品种类型、不同生长发育时期和不同部位且适配范围广的近红外漫反射光谱(NIRS)测定玉米秸秆体外干物质消化率(in vitro dry matter digestion,IVDMD)的稳定校正模型。其交叉验证和外部验证决定系数(R2_cv,R2_val)分别为0.907 3和0.906 6,预测标准偏差为2.08%, 预测值与化学值间的相关系数(r)达0.956。结果表明, 近红外光谱技术可以用于快速、准确测定玉米秸秆IVDMD,该结果对青贮玉米育种过程中的秸秆材料快速鉴定和筛选具有重要的意义。     

基于SVM算法的近红外光谱技术在鱼糜水分和蛋白质检测中的应用

采用支持向量机(support vector machine,SVM)建立了鱼糜样品中水分和蛋白质含量的近红外光谱校正模型,并采用独立样本集进行了预测。光谱数据经间隔两点一阶导数(DB1G2)、标准正态变换(SNV)、多元散射校正(MSC)相结合的方法预处理后,用偏最小二乘(PLS)降维处理,取前15个投影变量为自变量。获得水分模型的校正相关系数R_c、预测相关系数R_v、定标标准差SEE、预测标准差SEP; 蛋白质模型的校正相关系数R_c、预测相关系数R_v、定标标准差SEE、预测标准差SEP,有较好的预测准确性。基于SVM算法的近红外光谱技术可用于鱼糜水分和蛋白质含量的快速检测。     

基于OSC-PLS算法对大麦蛋白质含量进行定量分析的研究

用色散扫描型仪器采集大麦样品的近红外光谱,扫描出的光谱携带了大量样品化学值信息,采用正交信号校正(OSC)预处理方法对这些原始光谱进行处理,剔除噪声等不相关因子以后建立偏最小二乘(PLS)近红外光谱分析模型(OSC-PLS),预测大麦蛋白质的含量,并与传统PLS建模方法进行对比。基于OSC-PLS算法的蛋白质含量近红外光谱分析模型的测定系数R2为0.901,检验集的化学值与模型预测值的相关系数r达到0.971 7,分析模型的预测标准偏差SD为0.545 0,相对标准偏差RSD为4.2%。结果表明,OSC-PLS回归方法能在较大程度上消除无关因素的影响,在简化模型的同时提高了模型的可解释性,能够建立准确的大麦蛋白质含量近红外预测模型,可代替经典分析方法,满足农产品快速分析的需要。     

鱼粉中掺杂豆粕的可见和近红外反射光谱分析研究

探讨了基于可见和近红外反射光谱分析技术检测鱼粉中是否掺有植物饼粕的可行性。收集了我国常用的鱼粉和豆粕,将豆粕按不同浓度掺杂到鱼粉中制备试验样本,分别进行了定性和定量分析研究。定性分析用206个样本作为校正集,103个样本作为检验集,选择合适的光谱预处理方法和光谱范围建立了定性判别分析模型,模型对外部检验集的正确判断率为96.12％。定量分析用掺杂有豆粕的130个鱼粉样本作为校正集,65个鱼粉样本作为检验集,采用偏最小二乘法(PLS)建立了定量分析模型。以变量标准化处理(SNV)与二阶导数(2, 4, 4, 1)相结合处理效果最佳,其预测值和测量值的决定系数R2和标准差SEC分别为0.989 0和1.539 0;检验集进行外部验证的决定系数R2和标准差SEP分别为0.988 8和1.786 0,RPD为8.61。结果表明,利用近红外光谱分析技术可以成功检测鱼粉中豆粕的存在和含量。     

连续小波变换高光谱数据的土壤有机质含量反演模型构建

土壤有机质含量是反映土壤肥力的重要指标,对其进行动态监测是实施精准农业的重要措施。近年来,众多学者尝试采用土壤近地传感(proximal soil sensing),尤其是近地高光谱技术,在田间和实验室获取不同形态土壤的高光谱数据,不断引入新方法建立适用于不同地域和不同土壤类型的有机质含量的反演模型。该研究在实验室内利用ASD FS3采集了土壤高光谱数据,采用“重铬酸钾-外加热法”测得了土壤有机质含量;分析了土壤原始光谱反射率(R)与有机质含量的相关性,选取R2>0.15的敏感波段的反射率;利用CWT对土壤原始光谱反射率(R)、光谱反射率的连续统去除(CR)进行不同尺度的分解,分析小波系数与土壤有机质含量的相关性,选取R2>0.3的敏感波段的小波系数;利用R选取的波段信息和R-CWT,CR-CWT的选取的小波系数,分别建立偏最小二乘回归(PLSR)、BP神经网络(BPNN)、支持向量机回归(SVMR)三种不同的土壤有机质含量反演模型。结果表明：相比R与土壤有机质含量的决定系数R2,R-CWT,CR-CWT变换后得到的小波系数与土壤有机质含量的决定系数R2分别提高了0.15和0.2左右;CR-CWT-SVMR的模型效果最为显著,预测集的R2和RMSE分别为0.83,4.02,RPD值为2.48,具有较高的估测精度,能够全面稳定地估算土壤有机质含量;CR-CWT-PLSR的模型精度与CR-CWT-BPNN,CR-CWT-SVMR相比虽有一定差距,但是其计算量要明显小于非线性的BPNN和SVMR方法,具有模型简单、运算速度快等特点,对开发与设计田间传感器具有较大的应用价值。     

基于高光谱的牛奶中真蛋白质含量反演

牛奶蛋白质的分析和监测是奶制品行业中不可或缺的环节利用可见光/近红外反射光谱(350～2 500 nm)进行纯牛奶中真蛋白质含量的快速定量反演。分别通过ASD地物光谱仪和CEM真蛋白质测定仪采集牛奶样本的反射光谱数据以及蛋白质含量数据,对比分析不同的光谱预处理方法和波段筛选方法,得到特征波段,最后利用主成分回归(PCR)和最小二乘支持向量机(LS-SVM)模型建立牛奶反射光谱和蛋白质含量之间的定量校正模型,并对其预测能力进行比较,从而确定最优的牛奶中真蛋白质含量反演模型。实验结果证明：(1)比较不同光谱预处理方法,发现多元散射校正与二阶微分联合使用效果较好;(2)相对于全光谱建模,适当的特征变量优选有助于提高建模精度,缩短建模时间;(3)PCR的验证集决定系数R2_P为0.952 2,验证集均方根误差RMSEP为0.048 7,而LS-SVM的R2_P为0.958 0,RMSEP为0.048 2,其预测精度要优于PCR。研究表明,可见光/近红外高光谱反射率数据可以为牛奶真蛋白质含量的检测提供一种快速、无损的新方法。     

Acoustical experiment of yogurt fermentation process

One of the important factors through food manufacturing is hygienic management. Thus, food manufactures prove their hygienic activities by taking certifications like a Hazard Analysis and Critical Control Point (HACCP). This concept also applies to food monitoring. Acoustical measurements have advantage for other measurement in food monitoring because they make it possible to measure with noncontact and nondestructive. We tried to monitor lactic fermentation of yogurt by a probing sensor using a pair of acoustic transducers. Temperature of the solution changes by the reaction heat of fermentation. Consequently the sound velocity propagated through the solution also changes depending on the temperature. At the same time, the solution change its phase from liquid to gel. The transducers usage in the solution indicates the change of the temperature as the change of the phase difference between two transducers. The acoustic method has advantages of nondestructive measurement that reduces contamination of food product by measuring instrument. The sensor was inserted into milk with lactic acid bacterial stain of 19 degrees C and monitored phase retardation of propagated acoustic wave and its temperature with thermocouples in the mild. The monitoring result of fermentation from milk to Caspian Sea yogurt by the acoustic transducers with the frequency of 3.7 MHz started to show gradient change in temperature caused by reaction heat of fermentation but stop the gradient change at the end although the temperature still change. The gradient change stopped its change because of phase change from liquid to gel. The present method will be able to measure indirectly by setting transducers outside of the measuring object. This noncontact sensing method will have great advantage of reduces risk of food contamination from measuring instrument because the measurement probes are set out of fermentation reactor or food containers. Our proposed method will contribute to the hygienization for the food manufacture industry.     

Recent advances in the application of ultrasound in dairy products: Effect on functional,physical, chemical,microbiological and sensory properties

Alternative methods for improving traditional food processing have increased in the last decades. Additionally, the development of novel dairy products is gaining importance due to an increased consumer demand for palatable, healthy, and minimally processed products. Ultrasonic processing or sonication is a promising alternative technology in the food industry as it has potential to improve the technological and functional properties of milk and dairy products. This review presents a detailed summary of the latest research on the impact of high-intensity ultrasound techniques in dairy processing. It explores the ways in which ultrasound has been employed to enhance milk properties and processes of interest to the dairy industry, such as homogenization, emulsification, yogurt and fermented beverages production, and food safety. Special emphasis has been given to ultrasonic effects on milk components; fermentation and spoilage by microorganisms; and the technological, functional, and sensory properties of dairy foods. Several current and potential applications of ultrasound as a processing technique in milk applications are also discussed in this review.     

Power ultrasound in the meat industry (freezing,cooking and fermentation): Mechanisms,advances and challenges

High intensity ultrasound (HIUS) has a wide range of applications in different sectors of food processing. It is a promising and emerging technology demonstrating the potential to promote food processes without or at least damage to the quality of products. Among the processes of the meat industry, freezing, thawing, cooking and fermentation are very sensitive and important, because they have significant effects on product quality and are also very energy and time consuming. This review paper provides an interpretation of high intensity ultrasound (HIUS) applications, a summary of recent outstanding published research and an overview of the freezing/thawing, cooking/frying and fermentation processes in meat and its products assisted by HIUS. The effects, benefits and drawbacks as well as the challenges ahead in the commercialization of this technology in the meat industry are studied. The research results confirmed that the use of HIUS in the meat freezing/thawing, cooking/frying and fermentation in combination with the corresponding processing methods demonstrates a great potential to promote the process, improve the general quality of the final product and reduce the time and energy required. However, many issues remain that require further research to address these challenges. These challenges and subsequent research that is useful for developing and increasing the efficiency of this technology have been reviewed. After the literature review, it is concluded that HIUS may be a useful technology for meat processing because of its significant effects on the quality factors and related process variables that leads to the preservation of the initial nutritional and sensory properties of meat and its products. Of course, research must be continued to eliminate the disadvantages or minimize the undesirable effects of this technology on the final product and to remove barriers to commercialization and optimization of this method.     

Application of ultrasound technology in processing of ready-to-eat fresh food: A review

With the increase in food standardization and the pace of modern life, the demand for ready-to-eat foods is growing. The strong processing conditions of traditional technology often accelerate the rate of deterioration of quality, and microbes are the safety hazard of ready-to-eat foods. Ultrasound technology is an environmentally friendly technology that hardly causes thermal damage to raw materials. In this paper, the ultrasound technology is used in the disinfection, sterilization, enzyme inactivation, desensitization, dehydration, curing, tenderization and cooking process of fresh food from the perspective of microbial safety and quality of fresh food. The cavitation effect of ultrasound can improve the mass transfer rate of infiltration processes such as dehydration and curing, promote the oxidation of lipids and proteins for enrich the flavor of meat products, improve the microbiological safety and reduce the sensitization by destroying the integrity of the microbial cells and the conformation of the protein. In addition, ultrasound as an auxiliary processing technology can reduce the damage of traditional production technology to reserve the quality and nutritional value of food. Ultrasound has proved to be an efficient and green processing technology for ready-to-eat food.     

鲜牛奶变质过程的激光诱导荧光光谱研究

本文用激光诱导荧光（LIF）方法对鲜牛奶和酸牛奶变质过程进行了荧光光谱研究,介绍了所用测试系统的组成及测试方法,给出了变质过程荧光谱,并对测试结果进行了分析,研究表明,变质过程与荧光光谱之间存在密切联系。     

航空发动机尾气FTIR被动检测

航空发动机尾气排放情况可以反映发动机的燃烧状态,从而可以为发动机视情维修提供依据,同时可以为因尾气排放造成的环境污染分析提供依据,因此,对航空发动机尾气进行检测非常重要。由于传统的航空发动机尾气取样分析不方便,而且无法满足飞机爬升与空中飞行状态下的检测需要,文章将FTIR被动检测技术引入到航空发动机尾气检测中。首先详细介绍了FTIR被动检测原理和被检测气体浓度反演算法模型,接着分析了FTIR被动检测技术用于航空发动机尾气检测的可行性,给出了发动机尾气FTIR被动检测方法,最后利用布鲁克公司生产的Tensor27型FTIR对某航空发动机尾气进行了被动检测,得到了该发动机尾气中主要气体CO和NO的浓度,并与取样分析结果进行了比较,两者结果基本吻合,这表明FTIR被动检测技术满足航空发动机尾气检测要求。     

Prospects and application of ultrasound and magnetic fields in the fermentation of rare edible fungi

Ultrasound has the potential to be broadly applied in the field of agricultural food processing due to advantages such as environmental friendliness, low energy costs, no need for exogenous additives and ease of operation. High-frequency ultrasound is mainly used in medical diagnosis and in the food industry for the identification of ingredients and production line quality testing, while low-frequency ultrasounds is mainly used for extraction and separation, accelerating chemical reactions, auxiliary microbial fermentation and quality enhancement in food industry. Magnetic fields have many advantages of convenient use, such as non-toxic, nonpolluting and safe. High-intensity pulsed magnetic fields are widely used as a physical non-thermal sterilization technology in food processing, while weak magnetic fields are better at activating microorganisms and promoting their growth. Ultrasound and magnetic fields, due to their positive biological effects, have a wide range of applications in the food processing industry. This paper provides an overview of the research progress and applications of ultrasound and magnetic fields in food processing from the perspectives of their biological effects and mechanisms of action. Additionally, with the development and application of physical field technology, physical fields can now be used to provide significant technical advantages for assisting fermentation. Suitable physical fields can promote the growth of microbial cells, improve mycelial production and increase metabolic activity. Furthermore, the current status of research into the use of ultrasound and magnetic field technologies for assisting the fermentation of rare edible fungi, is discussed.     

光谱关键变量筛选在农产品及食品品质无损检测中的应用进展

农产品及食品的品质与安全一直以来都是人们关注的焦点,不仅关系着人们的身体健康,而且关系着社会稳定甚至国家安全。由于农产品及食品的品质不合格引发的安全事件备受社会各界的广泛关注。对农产品及食品的品质的监管长久以来都是分析检测领域的重点和难点。我国人口众多,对农产品和食品的消费量非常大。面对如此大量农产品及食品品质的无损快速检测需求,光谱法以其快速、无损、高效、环境友好、可现场检测等诸多特点,为农产品及食品品质的无损快速分析提供了良好的解决方案。然而,传统的光谱法在检测过程中所使用的数据量十分庞大,不仅在建立校正模型过程中会消耗大量时间,而且难以完成大量农产品及食品的品质在线高通量无损快速检测。大量数据的计算成为限制光谱类分析仪器工作效率的主要瓶颈之一,并且大量数据的计算对仪器设备的硬件配置也提出了非常高的要求,从而间接地提高了光谱分析技术的应用成本。近年来,关键变量筛选技术脱颖而出,并成为光谱分析的一个新热点。通过筛选,采用少量关键变量建立校正模型即可得到和全谱数据建模准确度相差无几的分析结果,从而可以有效提高分析仪器的工作效率并间接地降低光谱分析技术的应用成本,进而为农产品及食品品质的高通量检测提供了可靠的技术支持、为满足人民日益增长的美好生活需要提供科技保障。针对光谱关键变量筛选在粮食及粮食作物、蔬菜、水果、经济作物、肉类、食品品质与安全领域的无损检测应用进行综述,对光谱关键变量筛选技术的应用从筛选方法、应用范围、应用效果等方面进行了分类总结归纳,并就光谱关键变量筛选技术在农产品及食品品质无损检测中的应用从变量筛选方法特点及趋势、所选变量的稳定性和可靠性、所选变量的实际意义等方面进行了展望。     

粮油品质安全高光谱成像检测技术的研究进展

粮油品质安全至关人类营养健康与生命安全。常规检测粮油品质安全方法,由于操作困难、破坏性强、费用高、试剂污染等缺点,不能满足快速无损,高效无污染的要求,难以与工业4.0接轨。整合光谱和图像手段的高光谱成像技术,伴随着化学计量学的发展,突破了常规检测方法局限性,是粮油品质安全检测技术的发展趋势。在大量文献的基础上,综述了高光谱成像技术原理,以及在品质方面(组分测定、发芽检测、品种分类)和安全方面(真菌检测、虫害检测)的研究进展,特别分析了高光谱成像技术检测粮油品质安全的应用光谱范围、化学计量学方法、仪器设备和模型准确性,指出了现阶段在粮油品质安全检测中存在的主要问题,并对今后的研究方向和重点进行了展望,以期推动高光谱成像技术在粮油领域的应用发展。     

Advances in application of ultrasound in food processing: A review

Food processing plays a crucial role in coping up with the challenges against food security by reducing wastage and preventing spoilage. The ultrasound technology has revolutionized the food processing industry with its wide application in various processes, serving as a sustainable and low-cost alternative. This non-destructive technology offers several advantages such as rapid processes, enhanced process efficiency, elimination of process steps, better quality product and retention of product characteristics (texture, nutrition value, organoleptic properties), improved shelf life. This review paper summarizes the various applications of ultrasound in different unit operations (filtration, freezing, thawing, brining, sterilization/pasteurization, cutting, etc.) and specific food divisions (meat, fruits and vegetables, cereals, dairy, etc.) along with, the advantages and drawbacks of the technology. The further scope of industrial implementation of ultrasound has also been discussed.