鱼肉鲜度测定方法研究进展

综述了用于鱼肉鲜度测定的几类不同方法 ,包括感官评价方法、微生物学方法、物理和化学方法和生物传感器方法等 ,并比较了不同测定方法的特点 ,阐明了鱼肉鲜度测定方法的未来发展趋势。     

Texture and Structure Measurements and Analyses for Evaluation of Fish and Fillet Freshness Quality: A Review

Recently, food safety and quality have become critical issues of great concern throughout the world. Fish is one of the most vulnerable and perishable aquatic products. The evaluation of fish and fillet freshness is therefore very significant in research and development for providing premium and supreme quality for human health and acceptance by consumers, as well as for international trade. The texture and structure of fish muscle are important freshness quality attributes that depend on several parameters such as hardness, cohesiveness, springiness, chewiness, resilience, and adhesiveness, as well as the internal cross‐linking of connective tissue and the detachment of fibers. This review aims to present recent advances of texture and structure measurements and analyses, including sensory evaluation and instrumental methods, for indicating and evaluating fish freshness quality. Factors affecting these measurements are detailed and correlations between texture and structure are discussed. Moreover, the limitations and challenges of fish texture and structure measurements are described and some viewpoints about current work and future trends are also presented.     

Sensory and Chemical Evaluation of the Keeping Quality of the Brazilian Freshwater Fish Prochilodus scrofa in Ice Storage

The keeping quality of the freshwater fish Prochilodus scrofa in ice storage was investigated in two runs. Sensory evaluation of the raw fish reflected the progressive deterioration during storage. Sensory evaluation of the baked fish was less indicative of the state of freshness. None of the chemical analyses utilized (TVN, TBA, FFA, PV, qualitative tests) could be a reliable index of freshness. The keeping time was about 18 days in the first run and 12 days in the second run. Evisceration under commercial conditions did not extend the storage life.     

Microbial Sensors for the Detection of Fish Freshness

A microbial sensor system consisting of immobilized living spoilage-causing bacterium, Alteromonas putrefaciens, and an oxygen electrode was prepared and applied to the continuous determination of fish freshness. Fish freshness was expressed as a ratio of A/B, where A is the current decrease of the microbial sensor obtained by the application of l0–50 μL fish extract and B is the current decrease by the equivalent volume of culture medium. Freshness of bluefin tuna and yellowtail meats stored in ice for up to 2 weeks was determined by both the proposed and the conventional K value enzyme sensor method. Good comparative results were obtained. One assay could be completed within 13 min.     

Amperometric Determination of Fish Freshness by a Hypoxanthine Biosensor

The traditional determination of fish freshness is to detect total volatile basic nitrogen, microbial load or hypoxanthine. These methods are complex and expensive. A hypoxanthine biosensor was constructed by using immobilised xanthine oxidase and a platinum electrode. The enzyme was immobilised on a silk membrane. The electrode detected the hydrogen peroxide released during the enzymatic reaction. A linear range from 0·05 to 100×10⁻⁶ M of hypoxanthine was observed. When the method was applied to fish samples, the results obtained agreed well with those obtained by the conventional total volatile basic nitrogen and microbial load. This biosensor provides a reliable, simple, rapid and economical method for the measurement of fish freshness.     

Prolonging Shelf-Life of Carp by Combined Ionising Radiation and Refrigeration

Experiments were performed using ionisating radiation in order to prolong the shelf-life of two groups of refrigerated fish ( Cyprinus carpio ). After irradiation fish were kept at 0–2°C. Non-irradiated fish reached the non-acceptability point in 16 days and irradiated fish reached that point in 31 days. No difference was found between shelf-life of whole or eviscerated fish. If fish were immediately cooled to 0°C after death, their shelf-life was prolonged considerably. From this study it is clear that chemical tests of freshness such as TVB-N and K value determination are not appropriate for the study of irradiated fish. Organoleptic estimations and a new determination using an odour concentration meter seem to fit best the objective determination of freshness.     

Freshness monitoring of sea bream (Sparus aurata) with a potentiometric sensor

Freshness in one of the main quality attributes for fish commercialization and consumption. The traditional method for fish freshness evaluation is sensory analysis. However, instrumental methods such as electrical, texture and colour measurements, image analysis, VIS spectroscopy and electronic noses have been widely studied as objective alternatives. Each of these methods has advantages and disadvantages, but none of them can be universally proposed for defining and measuring fish freshness.     

Fish Quality Index Method: Principles,weaknesses, validation,and alternatives—A review

Fish is a high nutritional value matrix of which production and consumption have been increasing in the last years. Advancements in the efficient evaluation of freshness are essential to optimize the quality assessment, to improve consumer safety, and to reduce raw material losses. Therefore, it is necessary to use rapid, nondestructive, and objective methodologies to evaluate the quality of this matrix. Quality Index Method (QIM) is a tool applied to indicate fish freshness through a sensory evaluation performed by a group of assessors. However, the use of QIM as an official method for quality assessment is limited by the protocol, sampling size, specificities of the species, storage conditions, and assessor's experience, which make this method subjective. Also, QIM may present divergences regarding the development of microorganisms and chemical analysis. In this way, novel quality evaluation methods such as electronic noses, electronic tongues, machine vision system, and colorimetric sensors have been proposed, and novel technologies such as proteomics and mitochondrial analysis have been developed. In this review, the weaknesses of QIM were exposed, and novel methodologies for quality evaluation were presented. The consolidation of these novel methodologies and their use as methods of quality assessment are an alternative to sensory methods, and their understanding enables a more effective fish quality control.     

An Advanced Colour Calibration Method for Fish Freshness Assessment: a Comparison Between Standard and Passive Refrigeration Modalities

Freshness represents a pivotal aspect in fish product for both security and quality. Its evaluation still represents the key factor driving the consumer’ choices. Fish appearance is affected by many different factors that demand the contribution of different disciplines to be understood: from the physical and optical properties to the slaughtering and post-slaughtering conditions. An innovative preservation system is represented by the Passive Refrigeration PRS? developed for the preservation and transport of perishable food products. Scientific methods for product freshness evaluation may be conveniently divided into two categories: sensorial and instrumental. In this study, an instrumental method of colour calibration and discrimination is proposed at pilot scale for automatic evaluation of gilthead seabream (Sparus aurata) freshness. We propose a non-destructive method based on the colorimetric imaging of the whole external body of seabreams to evaluate through multivariate partial least squares which approach the differences in the freshness preservation under four refrigeration modalities. The matrix of the independent variables is represented by RGB values for each pixel belonging to an extracted region of interest (129,633 values). The dependent variable is composed by two dummy variable corresponding to fresh (T₀) or non-fresh (T₂) individuals. T₁ individuals were used as external test. The results quantified significant colorimetric differences between fresh and non-fresh fish. All fish used to create the model (T₀ and T₂) were correctly classified as fresh or non-fresh, while external test individuals (T₁) were all classified as fresh. The proposed imaging method merges different image analysis techniques: (a) colorimetric calibration, (b) morphometric superimposition and (c) partial least square discriminant analysis modelling. This innovative and non-destructive approach allows the automatic assessment of fish freshness.     

Physical,chemical and sensory analysis of sardine (Sardina pilchardus) stored in ice

The shelf-life of iced sardine (Sardina pilchardus) was studied. The main changes which take place in raw fish were investigated by means of organoleptic assessments, chemical analyses (total volatile nitrogen (TVB-N), trimethylamine (TMA-N), trimethylamine oxide (OTMA-N) and hypoxanthine) and physical measurements (GR Torrymeter readings and pH). The influence of both seasonal changes and fat deterioration were also considered. The results obtained indicate that TVB-N and TMA-N parameters are not good freshness indicators for this species, but Torrymeter readings and hypoxanthine values can be used as indicators of freshness. However, they must always be confirmed by a sensory evaluation. From the different combinations tried, the most highly significant degree of correlation was obtained between sensory evaluation and Torrymeter readings.     

Rapid Assessment of Fish Freshness and Quality by <Superscript>1</Superscript>H HR-MAS NMR Spectroscopy

A new analytical method that allows the rapid assessment of fish freshness and quality is presented. The method is based on ¹H high-resolution magic angle spinning (HR-MAS) NMR spectroscopy and allows the rapid determination of two well-established indicators of fish freshness and quality: the K value and the trimethylamine nitrogen (TMA-N) content. The method is demonstrated on four different species of fish (sea bream, sea bass, trout, and red mullet) stored on ice at 0 °C. The results obtained are in agreement with more cumbersome methods classically used to determine the K value and the TMA-N concentration. The main advantage of the ¹H HR-MAS NMR approach is to allow a direct measurement of these two parameters directly on unprocessed fish sample without using any preliminary extraction. The total analysis time, including sample preparation, is of the order of 40 min per sample.     

A nondestructive method for estimating freshness of freshwater fish

The traditional indictors of fish freshness including total aerobic count (TAC), K value, total volatile basic nitrogen (TVB-N), and sensory assessment (SA) were measured regularly to analyze the freshness changes during chill storage. Electric conduction property of whole fish was also studied by measuring their impedances under different frequencies as a fast nondestructive method. The relationship between traditional freshness indictors and electric conductivity was analyzed to determine the feasibility of evaluating fish freshness based on impedance change ratio (Q value) during storage. The results showed that traditional freshness indictors (TAC, K value, and TVB-N) values increased as storage time prolonged, while Q value and SA decreased. There were good relationships between Q value and TAC, K value, TVB-N, and SA (P < 0.01), with the correlation coefficients were 0.943, 0.996, 0.951, and 0.968, respectively. Thus, Q value can be used as a valid index for freshness evaluation and this method via measuring the electric conductivity property of whole fish is a fast nondestructive method for determining the freshness of fish during storage.     

生物传感器在鱼肉鲜度测定中的应用

综述了用于鱼肉鲜度测定的几种不同类型的生物传感器,包括K值测定传感器、微生物传感器和胺类测定传感器。阐明了生物传感器测定鱼肉鲜度的原理、特点及其发展趋势。     

Comparison of methods of differentiating between fresh and frozen–thawed fish or fillets

Freezing is an efficient way of storing fish. Objectively though, it is very hard to determine whether a fish has been previously frozen. Following an appraisal of various methods, we selected a physical determination (torrymeter), a physiological examination (eye lens) and three enzymatic assays (α‐glucosidase, β‐N‐acetylglucosaminidase and β‐hydroxyacyl‐CoA‐dehydrogenase) and applied them to three species: plaice (Pleuronectes platessa), whiting (Merlangus merlangus) and mackerel (Scomber scombrus). We also compared the results obtained following slow and rapid freezing and investigated how spoilage affects the torrymeter measurements and α‐glucosidase assay values. For whole fish the physical method using the torrymeter is a reliable indicator. For fish fillets we recommend the enzymatic method using the α‐glucosidase assay, which should be accompanied by measurement of the freshness to avoid confusing a frozen–thawed fish and a fish in an advanced stage of spoilage. The values noted for fresh and thawed whiting and plaice indicated cut‐off values of 0.15 for whiting and 0.5 for plaice, above which it can be asserted that the sample had been frozen. © 2002 Society of Chemical Industry     

Nondestructive Spectroscopic and Imaging Techniques for Quality Evaluation and Assessment of Fish and Fish Products

Nowadays, people have increasingly realized the importance of acquiring high quality and nutritional values of fish and fish products in their daily diet. Quality evaluation and assessment are always expected and conducted by using rapid and nondestructive methods in order to satisfy both producers and consumers. During the past two decades, spectroscopic and imaging techniques have been developed to nondestructively estimate and measure quality attributes of fish and fish products. Among these noninvasive methods, visible/near-infrared (VIS/NIR) spectroscopy, computer/machine vision, and hyperspectral imaging have been regarded as powerful and effective analytical tools for fish quality analysis and control. VIS/NIR spectroscopy has been widely applied to determine intrinsic quality characteristics of fish samples, such as moisture, protein, fat, and salt. Computer/machine vision on the other hand mainly focuses on the estimation of external features like color, weight, size, and surface defects. Recently, by incorporating both spectroscopy and imaging techniques in one system, hyperspectral imaging cannot only measure the contents of different quality attributes simultaneously, but also obtain the spatial distribution of such attributes when the quality of fish samples are evaluated and measured. This paper systematically reviews the research advances of these three nondestructive optical techniques in the application of fish quality evaluation and determination and discuss future trends in the developments of nondestructive technologies for further quality characterization in fish and fish products.     

鱼体新鲜度快速检测技术的研究进展

鱼类及其制品因营养价值高,近年来消费量急剧上升。但是,由于鱼体中含有大量的水分,鱼类组织的脆弱性以及酶和微生物的作用,使得鱼类及其制品易于腐败,造成鱼体品质迅速下降。因此,能快速有效地检测鱼体新鲜度对现代食品工业具有重要意义。本文综述了鱼体新鲜度快速检测技术的原理和应用,包括生物传感器技术(电化学生物传感器、酶生物传感器),感官仿生技术(电子鼻、电子舌、比色传感器阵列、计算机视觉技术)和光谱技术(可见/近红外光谱、高光谱、荧光光谱),总结了其优缺点,并对今后鱼体新鲜度快速检测技术的研究重点和发展趋势做出展望。     

鱼新鲜度对其烤鱼片中晚期糖基化终末产物形成的影响

本文以马面鱼为原料,基于4℃下7 d内挥发性盐基氮的变化判断鱼肉新鲜度,测定生鱼肉及烤鱼片中与晚期糖基化终末产物(Advanced Glycation End-products,AGEs)形成有密切关系的游离氨基酸、核苷酸、乙二醛等的含量变化,探究鱼新鲜度对其烤鱼片中AGEs形成的影响。结果表明:随着鱼肉新鲜度的降低,生鱼肉及烤鱼片中游离氨基酸和核苷酸的含量升高,烤鱼片中总AGEs、羧甲基赖氨酸、荧光性AGEs和戊糖素的含量在总体上均呈上升趋势,至7 d时总AGEs与羧甲基赖氨酸的含量分别达7.24与4.01 μg/g,说明原料鱼肉新鲜度对烤鱼片中AGEs的含量有重要影响;早中期糖基化产物乙二醛的含量在生鱼肉中变化不明显,但在烤鱼片中呈上升趋势,说明烤鱼片的加工过程与糖基化反应存在直接联系。     

Instrumental Texture Parameters as Freshness Indicators in Five Farmed Brazilian Freshwater Fish Species

The aim of this study was to assess the chemical quality and instrumental texture parameters, as well as their relationships, of five Brazilian freshwater fish species stored at 4 °C for 6 days. In general, ammonia, TCA-soluble peptides, and biogenic amine values increased with storage time, attributed to the advance of the deterioration process. Ammonia and TCA-soluble peptide concentrations correlated positively with the increase of putrescine, spermine, and histamine. Putrescine production began during the first days of storage, while cadaverine was produced later. Spermine and spermidine showed variable behavior, increasing and decreasing, respectively. With regard to the instrumental texture parameters, firmness, hardness, and chewiness decreased at the beginning of the storage period, whereas an increase was observed in springiness. All instrumental texture parameters demonstrated high correlations with ammonia and TCA-soluble peptides. The increase in certain biogenic amines (putrescine, cadaverine, and spermine) seems to correlate well with decreases observed in firmness, hardness, and chewiness. In addition, a strong relationship was observed between the initial days of storage and instrumental texture parameters, while a significant correlation between the end of the storage and the chemical quality analyses was verified. Firmness, hardness, chewiness, and cohesiveness were considered parameters with high potential in the evaluation of fish freshness during the first days of storage, whereas the chemical quality analyses and springiness were considered important for later evaluation of fish quality. Therefore, instrumental texture parameters may be used as quality indicators in the evaluation of freshwater fish freshness.     

几种鱼体新鲜度快速检测方法的研究进展

鱼类不耐贮藏容易腐败变质,新鲜度是鱼体品质和质量的重要指标,现代食品工业对于鱼和鱼类制品的新鲜度要求越来越高,鱼体新鲜度的快速检测方法的建立具有重要的科学意义和实践价值。文章将从仿生技术(包括电子鼻,电子舌技术),生物技术(包括生物传感器)以及其他物理化学技术(包括生物阻抗法,近红外光谱法)三方面介绍现今的几种用于鱼体新鲜度快速检测方法及其差异研究,并对今后鱼体新鲜度快速检测方法的发展做出一定的展望。      

Enzymatic Determination of Trimethylamine and Its Relationship to Fish Quality

An enzymatic procedure was developed to determine trimethylamine (TMA) in fish muscle extracts. The method utilized TMA dehydrogenase extracted and purified from Hyphomicrobium X and gave excellent correlations with the pick acid and HPLC methods. The minimum detectable TMA level was 0.05 μmoles. The entire enzymatic procedure required 15–20 min to complete. The method may be used in the laboratory as a spectrophotometric analysis or may be used semi-quantitatively as a visual color comparison test outside the laboratory. The method greatly simplifies the procedures for TMA determination and enables the estimation of microbiological quality of fish with very little laboratory equipment.