MEALINESS DETECTION IN APPLES USING TIME RESOLVED REFLECTANCE SPECTROSCOPY

Mealiness is a textural attribute related to internal fruit disorder that is characterized by the combination of abnormal softness of the fruit and absence of free juiciness in the mouth when eaten by the consumer. Time‐resolved laser reflectance spectroscopy was used as a tool to determine mealiness. This new technique in agrofood research may provide physical and chemical information independently and simultaneously, which is relevant to characterize mealiness. Using visible and near infrared lasers as light sources, time‐resolved laser reflectance spectroscopy was applied to Golden Delicious and Cox apples (n = 90), to characterize batches of untreated samples and samples that were stored under conditions that promote the development of mealiness (20C & 95% RH). The collected database was clustered into different groups according to their instrumental test values. The optical coefficients were used as explanatory variables to build discriminant functions for mealiness. The performance of the classification models created ranged from 47 to 100% of correctly identified mealy versus nonmealy apples.     

Recent Applications of Spectroscopic and Hyperspectral Imaging Techniques with Chemometric Analysis for Rapid Inspection of Microbial Spoilage in Muscle Foods

Muscle food is one of the most perishable food products because of its vulnerability to microbial spoilage, which can result in critical food safety problems. Traditional techniques for detection and evaluation of microbial spoilage in muscle foods are tedious, laborious, destructive, and time‐consuming. In recent years, spectroscopic and imaging technologies have shown great potentials for the assessment of food quality and safety due to their nondestructive, noninvasive, cost‐effective, and rapid responsive nature. This review focuses on the applications of several valuable spectroscopic techniques including visible and near‐infrared spectroscopy, Fourier transform infrared spectroscopy, fluorescence spectroscopy, Raman spectroscopy, and hyperspectral imaging for the rapid and nondestructive detection of microbial spoilage in common muscle foods such as meat, poultry, fish, and related products. Combined with chemometric analysis, such as spectral preprocessing and modeling methods, these potential technologies have been successfully developed for the determination of total viable count, aerobic plate count, Enterobacteriaceae, Pseudomonas, Escherichia coli, and lactic acid bacteria loads in muscle foods. Moreover, the advantages and disadvantages of these techniques are discussed and some perspectives about future trends are also presented.     

Principles of Hyperspectral Microscope Imaging Techniques and Their Applications in Food Quality and Safety Detection: A Review

Hyperspectral imaging (HSI) techniques play an important role in the food industry for providing rapid, nondestructive, and chemical‐free detection method, whereas a microscope can provide detailed information about the microstructure of a food item. As an emerging imaging spectroscopy technique, hyperspectral microscope imaging (HMI) technique combines the advantages of HSI with microscopic imaging and has been gradually applied in the food industry. This review introduces the principles of different kinds of HMI techniques, such as fluorescence HMI, visible/near‐infrared HMI, Raman HMI, and infrared HMI. Moreover, detailed applications of HMI techniques are summarized, including evaluation of structures of nutrients, and detection of microorganisms and residues. On the other hand, some challenges and future trends in the applications of these techniques are also discussed. It is concluded that by integrating HSI with microscopy, HMI can not only provide both spectral and spatial information about food substances but also provide their chemical information at the molecular or cellular level. Therefore, HMI techniques have great potentials in nondestructive evaluation of structures of nutrients, and detection of microorganisms and residues for the food industry.     

Emerging techniques for determining the quality and safety of tea products: A review

Spectroscopic techniques, electrochemical methods, nanozymes, computer vision, and modified chromatographic techniques are the emerging techniques for determining the quality and safety parameters (e.g., physical, chemical, microbiological, and classified parameters, as well as inorganic and organic contaminants) of tea products (such as fresh tea leaves, commercial tea, tea beverage, tea powder, and tea bakery products) effectively. By simplifying the sample preparation, speeding up the detection process, reducing the interference of other substances contained in the sample, and improving the sensitivity and accuracy of the current standard techniques, the abovementioned emerging techniques achieve rapid, cost‐effective, and nondestructive or slightly destructive determination of tea products, with some of them providing real‐time detection results. Applying these emerging techniques in the whole industry of tea product processing, right from the picking of fresh tea leaves, fermentation of tea leaves, to the sensory evaluation of commercial tea, as well as developing portable devices for real‐time and on‐site determination of classified and safety parameters (e.g., the geographical origin, grade, and content of contaminants) will not only eliminate the strong dependence on professionals but also help mechanize the production of tea products, which deserves further research. Conducting a review on the application of spectroscopic techniques, electrochemical methods, nanozymes, computer vision, and modifications of chromatographic techniques for quality and safety determination of tea products may serve as guide for other types of foods and beverages, offering potential techniques for their detection and evaluation, which would promote the development of the food industry.     

Textural and Rheological Properties of Cooked Potatoes

Cooked potato samples of different cultivars and specific gravities were analyzed for textural and rheological properties by sensory evaluation, texture profile analysis (TPA) and stress relaxation tests. Mealiness was correlated with the product of cohesiveness and adhesiveness, but not with other TPA parameters. Stress relaxation tests of cooked potatoes yielded a Maxwell model consisting of two viscous and three elastic elements. One of the elastic moduli was correlated with mealiness. Hardness by sensory evaluation correlated well with hardness and fracturability by TPA, and with the three elastic moduli in the relaxation model.     

Research advancements in optical imaging and spectroscopic techniques for nondestructive detection of mold infection and mycotoxins in cereal grains and nuts

Cereal grains and nuts are represented as the economic backbone of many developed and developing countries. Kernels of cereal grains and nuts are prone to mold infection under high relative humidity and suitable temperature conditions in the field as well as storage conditions. Health risks caused by molds and their molecular metabolite mycotoxins are, therefore, important topics to investigate. Strict regulations have been developed by international trade regulatory bodies for the detection of mold growth and mycotoxin contamination across the food chain starting from the harvest to storage and consumption. Molds and aflatoxins are not evenly distributed over the bulk of grains, thus appropriate sampling for detection and quantification is crucial. Existing reference methods for mold and mycotoxin detection are destructive in nature as well as involve skilled labor and hazardous chemicals. Also, these methods cannot be used for inline sorting of the infected kernels. Thus, analytical methods have been extensively researched to develop the one that is more practical to be used in commercial detection and sorting processes. Among various analytical techniques, optical imaging and spectroscopic techniques are attracting growers’ attention for their potential of nondestructive and rapid inline identification and quantification of molds and mycotoxins in various food products. This review summarizes the recent application of rapid and nondestructive optical imaging and spectroscopic techniques, including digital color imaging, X-ray imaging, near-infrared spectroscopy, fluorescent, multispectral, and hyperspectral imaging. Advance chemometric techniques to identify very low-level mold growth and mycotoxin contamination are also discussed. Benefits, limitations, and challenges of deploying these techniques in practice are also presented in this paper.     

Comparative review and the recent progress in detection technologies of meat product adulteration

Meat adulteration, mainly for the purpose of economic pursuit, is widespread and leads to serious public health risks, religious violations, and moral loss. Rapid, effective, accurate, and reliable detection technologies are keys to effectively supervising meat adulteration. Considering the importance and rapid advances in meat adulteration detection technologies, a comprehensive review to summarize the recent progress in this area and to suggest directions for future progress is beneficial. In this review, destructive meat adulteration technologies based on DNA, protein, and metabolite analyses and nondestructive technologies based on spectroscopy were comparatively analyzed. The advantages and disadvantages, application situations of these technologies were discussed. In the future, determining suitable indicators or markers is particularly important for destructive methods. To improve sensitivity and save time, new interdisciplinary technologies, such as biochips and biosensors, are promising for application in the future. For nondestructive techniques, convenient and effective chemometric models are crucial, and the development of portable devices based on these technologies for onsite monitoring is a future trend. Moreover, omics technologies, especially proteomics, are important methods in laboratory detection because they enable multispecies detection and unknown target screening by using mass spectrometry databases.     

Emerging Spectroscopic and Spectral Imaging Techniques for the Rapid Detection of Microorganisms: An Overview

Microorganism contamination and foodborne disease outbreaks are of public concern worldwide. As such, the food industry requires rapid and nondestructive methods to detect microorganisms and to control food quality. However, conventional methods such as culture and colony counting, polymerase chain reaction, and immunoassay approaches are laborious, time‐consuming and require trained personnel. Therefore, the emergence of rapid analytical methods is essential. This review introduces 6 spectroscopic and spectral imaging techniques that apply infrared spectroscopy, surface‐enhanced Raman spectroscopy, terahertz time‐domain spectroscopy, laser‐induced breakdown spectroscopy, hyperspectral imaging, and multispectral imaging for microorganism detection. Recent advances of these technologies from 2011 to 2017 are outlined. Challenges in the application of these technologies for microorganism detection in food matrices are addressed. These emerging spectroscopic and spectral imaging techniques have the potential to provide rapid and nondestructive detection of microorganisms. They should also provide complementary information to enhance the performance of conventional methods to prevent disease outbreaks and food safety problems.     

Sensory and Chemical/Physical Quality Criteria of Frozen Peas Studied by Multivariate Data Analysis

Ninety-six batches of peas (Pisum sativum L. var.meduflare Alef.) chosen to represent many different types of quality variations, were analysed for 11 sensory and 11 chemical/physical variables. Mealiness, hardness, fruity and sweet flavor were found to be relevant sensory quality criteria by Principal Component Analysis and Analysis of Variance. These internal quality criteria seemed to describe a type of variation different from external quality variables such as color, appearance and size. About 60% of the total variation in the sensory variables could be predicted by the chemical/physical measurements as modelled by a two-block Partial Least Squares Regression method. Alcohol insoluble solids contributed the most, especially to describe the “water” variation represented by mealiness and juiciness. The sensory and chemical/physical quality criteria were interpreted in terms of quality variations in the material as mainly due to maturation and growing seasons.     

Recent Advances in Nondestructive Analytical Techniques for Determining the Total Soluble Solids in Fruits: A Review

The total soluble solids play an important role in the fruit maturity process and determine the acceptance of rich nutrients as well as economic benefits in the fruit trade. Thus, development of rapid and nondestructive techniques for evaluating soluble solids content in fruits is important. This review focuses on recent advances in nondestructive techniques for soluble solids contents of fruits including hyperspectral imaging, laser light backscattering imaging, magnetic resonance imaging, X‐ray computed tomography, near‐infrared spectroscopy, and Raman spectroscopy. The advantages and disadvantages of these techniques are compared and discussed, and some viewpoints about future trends are also presented.     

Recent advances in rapid and nondestructive determination of fat content and fatty acids composition of muscle foods

Conventional methods for determining fat content and fatty acids (FAs) composition are generally based on the solvent extraction and gas chromatography techniques, respectively, which are time consuming, laborious, destructive to samples and require use of hazard solvents. These disadvantages make them impossible for large-scale detection or being applied to the production line of meat factories. In this context, the great necessity of developing rapid and nondestructive techniques for fat and FAs analyses has been highlighted. Measurement techniques based on near-infrared spectroscopy, Raman spectroscopy, nuclear magnetic resonance and hyperspectral imaging have provided interesting and promising results for fat and FAs prediction in varieties of foods. Thus, the goal of this article is to give an overview of the current research progress in application of the four important techniques for fat and FAs analyses of muscle foods, which consist of pork, beef, lamb, chicken meat, fish and fish oil. The measurement techniques are described in terms of their working principles, features, and application advantages. Research advances for these techniques for specific food are summarized in detail and the factors influencing their modeling results are discussed. Perspectives on the current situation, future trends and challenges associated with the measurement techniques are also discussed.     

Monitoring post-harvest quality of Granny Smith apple under simulated shelf-life conditions: destructive, non-destructive and analytical measurements

The purpose of this research was to use destructive and non-destructive measurement methods to evaluate Granny Smith apple quality changes under room storage conditions (20°C, 65% relative humidity) and to relate it to internal structure changes as observed using light microscopy. The Granny Smith apple Firmness was non-destructively measured with forced vibration and acoustic impulse techniques. At the determined time intervals, compression and tensile tests were carried out to determine apple Flesh mechanical properties. The cell-wall rupture was examined with light microscopy. The pH value, internal air space (IAS), soluble solids concentration (SSC), colour changes and weight losses of the apples were also monitored during storage. Apple Firmness measured with forced vibration correlated well with the impulse test. The acoustic impulse measurement had less deviation compared with the vibration test. The pH value and IAS increased during storage at room temperature. The Granny Smith apple has a long storage life and the criteria for the mealiness are suggested from compression and tensile tests.     

Emerging nondestructive approaches for meat quality and safety evaluation—A review

Meat is one of the most consumed agro-products because it contains proteins, minerals, and essential vitamins, all of which play critical roles in the human diet and health. Meat is a perishable food product because of its high moisture content, and as such there are concerns about its quality, stability, and safety. There are two widely used methods for monitoring meat quality attributes: subjective sensory evaluation and chemical/instrumentation tests. However, these methods are labor-intensive, time-consuming, and destructive. To overcome the shortfalls of these conventional approaches, several researchers have developed fast and nondestructive techniques. Recently, electronic nose (e-nose), computer vision (CV), spectroscopy, hyperspectral imaging (HSI), and multispectral imaging (MSI) technologies have been explored as nondestructive methods in meat quality and safety evaluation. However, most of the studies on the application of these novel technologies are still in the preliminary stages and are carried out in isolation, often without comprehensive information on the most suitable approach. This lack of cohesive information on the strength and shortcomings of each technique could impact their application and commercialization for the detection of important meat attributes such as pH, marbling, or microbial spoilage. Here, we provide a comprehensive review of recent nondestructive technologies (e-nose, CV, spectroscopy, HSI, and MSI), as well as their applications and limitations in the detection and evaluation of meat quality and safety issues, such as contamination, adulteration, and quality classification. A discussion is also included on the challenges and future outlooks of the respective technologies and their various applications.     

Nondestructive quality evaluation of agro-products using acoustic vibration methods—A review

ABSTRACT

Quality evaluation of agro-products is quite important because it is the basis for growers, distributers, and consumers. Various novel and emerging nondestructive methods were proposed for quality evaluation of agro-products. The acoustic vibration method is one of the major nondestructive methods for agro-products in pre- and postharvest research and industrial practice. Acoustic vibration characteristics of agro-products can be used for texture evaluation, prediction of optimum eating and harvest ripeness, ripeness classification and defect detection. Generally, there are three parts in the process of acoustic vibration method, including the excitation module, signal acquisition module, and signal-processing module. The impact method and forced method are two excitation methods in the excitation module, and there are contact and noncontact sensors for vibration measurement in the signal acquisition module. Noncontact measurement can meet the requirement of rapid and nondestructive measurement, especially for the on-line detection. However, increasing demand for accurate and cost-effective measurement remains a challenge in the agro-products industry. Comparison of acoustic vibration methods and traditional destructive methods was also discussed, which helps to give a more comprehensive assessment for the acoustic vibration method.     

Emerging Biorecognition and Transduction Schemes for Rapid Detection of Pathogenic Bacteria in Food

The presence of unsafe levels of microorganisms in food constitutes a growing economic and public health problem that necessitates new technology for their rapid detection along the food continuum from production to consumption. While traditional techniques are reliable, there is a need for more sensitive, selective, rapid, and cost‐effective approaches for food safety evaluation. Methods such as microbiological counts are sufficiently accurate and inexpensive, and are capable of determining presence and viability for most pathogens. However, these techniques are time consuming, involve destructive sampling, and require trained personnel and biosafety‐certified facilities for analysis. Molecular techniques such as the polymerase chain reaction have greatly improved analytical capability over the last decade, achieving shorter analysis time with quantitative data and strain specificity, and in some cases the ability to discriminate cell viability. The emerging field of nanosensors/biosensors has demonstrated a variety of devices that hold promise to bridge the gap between traditional plate counting and molecular techniques. Many nanosensors/biosensors are rapid, portable, accurate devices that can be used as an additional screening tool for identifying unsafe levels of microorganisms in food products with no need for pre‐enrichment. In this review, we provide a brief overview of available biorecognition–transduction techniques for detecting bacteria in food. We then discuss the advantages and disadvantages of each technique, and describe some recent biosensor or nanosensor technologies that are under development. We conclude by summarizing the opportunities and challenges in the field of pathogen monitoring in food systems and we focus the discussion on the strengths/weaknesses of the most popular biorecognition agents and transducer nanomaterials for biosensing.     

肉品品质的无损检测方法(英文)

At present, some foreign researchers of meat industry developed countries are studying and applying nondestructive testing techniques to detect meat quality.In our country, these techniques are seldom used besides some techniques using electromagnetic properties.This paper introduces some modern nondestructive testing techniques for quality detection of meat, such as Supersonic wave, electronic Nose, electromagnetic method, near infrared, Raman Spectroscopy and computer vision technology.These techniques can meet the requirements of high speed and high accuracy on line detection of meat.Besides, further research and possible applications are also discussed.     

Genetic diversity of organoleptic properties in water yam (Dioscorea alata L)

Improving the food quality of yams (Dioscorea spp) is an ongoing challenge to yam breeders and researchers. Forty accessions of D alata were evaluated for the suitability of their tubers for the preparation of two dominant food forms (boiled and pounded) as part of an effort to identify potential parents for use in genetic improvement. Trained panellists were presented with randomised, replicated and coded samples of boiled yam tuber pieces and asked to rate them for mealiness, colour, wetness, softness and taste. The sensory attributes considered for pounded yam (dough from boiled and pounded tubers) were consistency, colour, sheen, smoothness, stickiness, elasticity and hardness. Ratings were based on hedonic scales. Cluster analysis revealed groupings of accessions into eight and nine similarity clusters for boiled yam and pounded yam respectively. The mean scores for general preference were regressed on individual attribute scores. Mealiness, colour and taste were important in the general preference for boiled yam. Consistency, colour and stickiness determined the general preference for pounded yam. Of the accessions, 67% were identified as being suitable for preparation as a boiled vegetable, while 55% were assessed to be good for pounded yam, based on the respective quality attributes evaluated. © 2003 Society of Chemical Industry     

桃品质的无损检测技术研究进展

桃果实营养物质丰富,是消费者青睐的水果之一。但桃在生长、采摘和贮藏过程中易受到损害而导致品质下降,严重影响桃的经济价值,因此桃品质检测技术对于保障果实商业价值具有至关重要的作用。传统的检测方法具有耗时长、成本高、对样品有破坏性等缺点,而基于声学特性、力学特性、介电特性、光学特性和电子鼻的无损检测方法,特别是基于光学特性的检测方法,因其无损、快速、准确的优势而发展迅速,目前在桃果实内外部品质检测中得到广泛的应用,然而目前对其优缺点及今后的发展方向缺乏系统总结。本文综述应用上述无损检测技术,尤其是基于光学特性和电子鼻的无损检测方法,评估桃果实外部品质（大小、形状、色泽、香气、表面缺陷）和内部品质（品种、糖度、可滴定酸含量、硬度、冷害、虫害等）的最新研究进展,总结分析了其在桃品质检测中存在的问题,并对桃品质无损检测研究方向进行展望,以期为桃品质无损检测技术的研究提供参考。     

Roadmap of cocoa quality and authenticity control in the industry: A review of conventional and alternative methods

Cocoa (Theobroma cacao L.) and its derivatives are appreciated for their aroma, color, and healthy properties, and are commodities of high economic value worldwide. Wide ranges of conventional methods have been used for years to guarantee cocoa quality. Recently, however, demand for global cocoa and the requirements of sensory, functional, and safety cocoa attributes have changed. On the one hand, society and health authorities are increasingly demanding new more accurate quality control tests, including not only the analysis of physicochemical and sensory parameters, but also determinations of functional compounds and contaminants (some of which come in trace quantities). On the other hand, increased production forces industries to seek quality control techniques based on fast, nondestructive online methods. Finally, an increase in global cocoa demand and a consequent rise in prices can lead to future cases of fraud. For this reason, new analytes, technologies, and ways to analyze data are being researched, developed, and implemented into research or quality laboratories to control cocoa quality and authenticity. The main advances made in destructive techniques focus on developing new and more sensitive methods such as chromatographic analysis to detect metabolites and contaminants in trace quantities. These methods are used to assess cocoa quality; study new functional properties; control cocoa authenticity; or detect frequent emerging frauds. Regarding nondestructive methods, spectroscopy is the most explored technique, which is conducted within the near infrared range, and also within the medium infrared range to a lesser extent. It is applied mainly in the postharvest stage of cocoa beans to analyze different biochemical parameters or to assess the authenticity of cocoa and its derivatives.     

肉品品质的无损检测方法

目前,国外肉品生产发达国家正在研究与应用无损检测手段进行肉品的品质评定。本文介绍了肉品品质的各种无损检测方法的基本原理、作用及其优缺点,包括超声波检测技术、利用电磁学方法检测(主动特性法和核磁共振波谱分析技术)、电子气味检测法(电子鼻)、光学方法(近红外光谱分析技术和激光喇曼光谱技术)和计算机视觉检测技术。