Accelerated chemotaxonomic discrimination of marine fish surimi based on Tri-step FT-IR spectroscopy and electronic sensory

Research advances in detection of food adulteration and application of MALDI-TOF MS: A review

Food adulteration and illegal supplementations have always been one of the major problems in the world. The threat of food adulteration to the health of consumers cannot be ignored. Food of questionable origin causes economic losses to consumers, but the potential health risks cannot be ignored. However, the traditional detection methods are time-consuming and complex. This review mainly discusses the types of adulteration and technologies used to detect adulteration. Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) is also emphasized in the detection of adulteration and authenticity of origin analysis of various types of food (milk, meat, edible oil, etc.), and the future application direction and feasibility of this technology are analyzed. On this basis, MALDI-TOF MS was compared with other detection methods, highlighting the advantages of this technology in the detection of food adulteration. The future development prospect and direction of this technology are also emphasized.

Gelatinous quality and quantitative proteomic analyses of snakehead (Channa argus) surimi treated by atmospheric cold plasma

In this study, the comprehensive quality characteristics and proteome changes of snakehead (Channa argus) surimi gel under different atmospheric cold plasma (ACP) treatment times were systematically analyzed and compared. The results showed that the ubiquitin-associated proteins and heat shock proteins were activated after ACP treatment for 90 s (ACP90), thus inducing rearrangement of surimi structural proteins. Meanwhile, the increased hydrophobic interactions and disulfide bonds might strengthen the interactions among the myofibrillar protein, keratin, and type-I collagen, which led to the formation of a dense gel network. Moreover, the high nodality between actin and myosin promoted the regulation of muscle contraction by changing the spatial obstruction of their binding sites. These beneficial effects obviously contributed to the superior water-holding capacity (76.13%), gel strength (285.6 g·cm) and viscoelasticity of snakehead surimi in the ACP90 group. These results would provide some useful information for the in-depth and efficient processing of surimi products.

Interpreting the variation in particle size of ground spice by high-resolution visual and spectral imaging: A ginger case study

High-resolution (HR) visual imaging and spectral imaging are common computer vision-based techniques used for food quality analysis and/or authentication based on the interaction of light and material surface and/or composition. The particle size of ground spices is an important morphological feature that affects the physico-chemical properties of food products containing such particles. This study aimed to interpret the impact of particle size of ground spice on its HR visual profile and spectral imaging profile using ginger powder as a representative spice powder model. The results revealed an increase in the light reflection with the decrease of particle size of ginger powder, which was manifested by the lighter colour (higher percentage of the colour code with lighter yellow colour) of the HR visual image and stronger reflection with spectral imaging. The study also revealed that, in spectral imaging, the influence of the particle size of ginger powder increased with rising wavelengths. Finally, the results indicated a relationship between spectral wavelengths, ginger particle size, and other natural variables of the products which might be generated from cultivation to processing. Ultimately, the impact of natural variables arising during the food production process on the physico-chemical properties of the product should be fully considered or even additionally evaluated prior to the application of specific food quality and/or authentication analytical techniques.

Effects of temperature fluctuations on non-volatile taste compounds in tilapia fillets (Oreochromis niloticus)

In this study, the effect of temperature fluctuations on the taste quality of tilapia fillets during frozen storage was investigated. Major temperature-responsive factors included free amino acids (FAAs) and flavor nucleotides in fish fillets, which were identified using multidimensional infrared spectroscopy (MM-IR). The main FAA in tilapia fillets is a sweet amino acid (glycine). Compared with the control group, the umami FAAs and sweetness FAAs were significantly increased, and the total FAAs content increased to 1.30 times after the ninth fluctuation, reaching the highest level (611.16 ± 73.60 mg/100 g). Considering the equivalent umami intensity values, adenosine monophosphate and inosine monophosphate were retained during the first and second temperature fluctuations. In addition, the content of Na⁺, K⁺, and Ca²⁺ decreased (P < 0.05). Therefore, MM-IR is an effective method to identify taste components. With regard to taste quality, temperature fluctuations in the twofold range have an umami-enhancing effect.

Characteristics of germinated corn flour and influence of germination on cookie properties

The aim of this study was to investigate the effect of germination on the physicochemical, structure, pasting, and morphological properties of corn. Germination improved total phenolic content (TPC) and antioxidant capacity (AC). Scanning electron micrographs (SEM) of flour showed that some starch granule was destroyed with germination. In the same way, pasting values decreased due to changes in the starch granule. FT-IR (Fourier Transform Infrared) spectra confirmed that germination leads to changes in the chemical structure. The XRD (X-ray diffractometer) analysis showed that patterns did not change with germination. In addition, raw and germinated corn flour were used in gluten-free cookie preparation. The cookie dough was evaluated for stickiness. The physical, textural, colour, TPC, and AC of cookie samples were determined. Gluten-free cookies prepared with germinated flour exhibited significantly higher AC due to increase in TPC. Germination could be used to enhance functional properties of corn.

Direct authentication and composition quantitation of red wines based on Tri-step infrared spectroscopy and multivariate data fusion

A robust data fusion strategy integrating Tri-step infrared spectroscopy (IR) with electronic nose (E-nose) was established for rapid qualitative authentication and quantitative evaluation of red wines using Cabernet Sauvignon as an example. The chemical fingerprints of four types of wines were thoroughly interpreted by Tri-step IR, and the defined spectral fingerprint region of alcohol and sugar was 1200-950 cm^-1. The wine types were authenticated by IR-based principal component analysis (PCA). Furthermore, ten quantitative models by partial least squares (PLS) were built to evaluate alcohol and total sugar contents. In particular, the model based on the fusion datasets of spectral fingerprint region and E-nose was superior to the others, in which RMSEP reduced by 47.95% (alcohol) and 79.90% (total sugar), r_p increased by 11.95% and 43.47%, and RPD >3.0. The developed methodology would be applicable for mass screening and rapid multi-chemical-component quantification of wines in a more comprehensive and efficient manner.

Applications of Non-invasive and Novel Methods of Low-Field Nuclear Magnetic Resonance and Magnetic Resonance Imaging in Aquatic Products

Aquatic products, such as fish, are popular throughout the world due to their satisfying flavor characteristics as well as rich animal nutrition, and they provide high-value food therapy, but they are easily oxidized and spoiled. It is necessary to detect aquatic products through rapid and accurate technology. Low-field nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging (MRI) have been widely used in the aquatic product industry due to their sensitivity, fast analysis, non-destructive nature and low cost. The applications of LF-NMR in the measurement of aquatic product quality and nutrients (water, fat, and protein) are summarized in this paper. Applications in aquatic products have been shown to depend on deep processing, storage and authentication. This review discusses the application of MRI technology in the quality control of aquatic products. Therefore, this review will guide the application of the aquatic products industry and aims to supply the reader with both the theory of the method and practical applications of the method for use as a rapid and non-destructive technology in scientific research and the industrial industry.

A novel method based on infrared spectroscopic inception-resnet networks for the detection of the major fish allergen parvalbumin

We have developed a novel approach that involves inception-resnet network (IRN) modeling based on infrared spectroscopy (IR) for rapid and specific detection of the fish allergen parvalbumin. SDS-PAGE and ELISA were used to validate the new method. Through training and learning with parvalbumin IR spectra from 16 fish species, IRN, support vector machine (SVM), and random forest (RF) models were successfully established and compared. The IRN model extracted highly representative features from the IR spectra, leading to high accuracy in recognizing parvalbumin (up to 97.3%) in a variety of seafood matrices. The proposed infrared spectroscopic IRN (IR-IRN) method was rapid (~20 min, cf. ELISA ~4 h) and required minimal expert knowledge for application. Thus, it could be extended for large-scale field screening and identification of parvalbumin or other potential allergens in complex food matrices.

Structural and antimicrobial properties of Maillard reaction products in chicken liver protein hydrolysate after sonication

This study aimed to investigate the structural and antimicrobial properties of Maillard reaction products (MRPs) in chicken liver protein (CLP) and its hydrolysate (CLPH) after sonication (SCLPH). The MRPs of CLP (CLPM), CLPH (CLPHM) and SCLPH (SCLPHM) were analyzed by several spectrometric techniques. The molecular weights of the CLPHM and SCLPHM were primarily between 1.35 kDa and 17 kDa. Moreover, the molecular weights in the CLPHM and SCLPHM below 1.35 kDa were increased, which indicated that cross-linking and thermal degradation occurred during the Maillard reaction (MR). The SCLPHM showed an obvious network skeleton, and the surface had many small crystal-shaped particles after ultrasound treatment and MR by scanning electron microscopy. The SCLPHM had more negative charges than the CLPHM, thus effectively inhibiting the growth of S. saprophyticus and E. coli. MR and ultrasound treatment could be a promising technology to expand the application prospects of low-value meat byproducts.

Rapid discrimination of Chinese dry-cured hams based on Tri-step infrared spectroscopy and computer vision technology

The aim of this study was to establish rapid and efficient methods based on a Tri-step infrared spectroscopy (Fourier transform infrared spectroscopy (FT-IR) integrated with second derivative infrared spectroscopy (SD-IR) and two-dimensional correlation infrared spectroscopy (2DCOS-IR)) and computer vision technology to identify and evaluate the quality of three Chinese dry-cured hams (Jinhua, Xuanwei and Rugao hams). 9 dry-cured hams (3 different quality grades of each geographical origin) had similar IR spectra. Nevertheless, they could be further discriminated visually by SD-IR and 2DCOS-IR spectra. All samples can be separated by the computer vision technology incorporated with Principal Component Analysis (PCA) and Cluster analysis (CA). This study not only preliminarily verified the possibility of using Tri-step infrared spectroscopy and computer vision technology to discriminate the geographical origins and quality grades of Chinese dry-cured hams, but also provided prospects of the application of infrared spectroscopy and computer vision technology to authenticate other meat products.

Geographical origin traceability of Cabernet Sauvignon wines based on Infrared fingerprint technology combined with chemometrics

Mid-infrared (MIR) and near-infrared (NIR) spectroscopy combined with chemometrics were explored to classify Cabernet Sauvignon wines from different countries (Australia, Chile and China). Commercial wines (n = 540) were scanned in transmission mode using MIR and NIR, and their characteristic fingerprint bands were extracted at 1750-1000 cm⁻¹ and 4555-4353 cm⁻¹. Through the identification system of Tri-step infrared spectroscopy, the correlation between macroscopic chemical fingerprints and geographical regions was explored more deeply. Furthermore, Principal component analysis (PCA), soft independent modelling of class analogy (SIMCA) and discriminant analysis (DA) based on MIR and NIR spectra were used to visualize or discriminate differences between samples and to realize geographical origin traceability of Cabernet Sauvignon wines. Through “external test set (n = 157)” validation, SIMCA models correctly classified 97%, 97% and 92% of Australian, Chilean and Chinese Cabernet Sauvignon wines, while the DA models correctly classified 86%, 85% and 77%, respectively. Based on unique digital fingerprints of spectroscopy (FT-MIR and FT-NIR) associated with chemometrics, geographical origin traceability was achieved in a more comprehensive, effective and rapid manner. The developed database models based on IR fingerprint spectroscopy with chemometrics could provide scientific basis and reference for geographical origin traceability of Cabernet Sauvignon wines (Australia, Chile and China).

Integrated recognition and quantitative detection of starch in surimi by infrared spectroscopy and spectroscopic imaging

Surimi products have become increasingly-consumed food with prominent characteristics of high nutrition and convenience and its supply falls short of demand. However, due to exhausted fishery resource in recent years, surimi adulteration, such as addition of plant proteins, starch and other animal origin meat, is becoming serious, so recognition of these exogenous substances has become an urgent issue. In this study, Fourier transform infrared spectroscopy (FT-IR) combined with infrared spectroscopic imaging could distinguish heterogeneity in surimi qualitatively and quantitatively and obtain integral chemical images so that spatial distribution of each component in surimi could be visually displayed, thus a rapid recognition method and a prediction model were developed. The different starch contents in surimi had been primarily identified through intensity change of infrared absorption peaks at 1045cm^-1 and 988cm^-1, specifically with peak shifts to 1041cm^-1 and to 992cm^-1, respectively. In infrared imaging analysis, principal components (PCs) were separated and one key PC was confirmed as starch by characteristic peaks comparison at 1147cm^-1, 1075cm^-1, 997cm^-1 and 930cm^-1. Meanwhile, an established statistic model could predict starch content in surimi correctly with a reliable correlation coefficient (R=0.9856) and root mean square error of prediction (RMSEP=5.64). Therefore, FT-IR combined with infrared spectroscopic imaging could be applicable to integrally recognize and quantitatively detect starch in surimi.

Enhanced chemical and spatial recognition of fish bones in surimi by Tri-step infrared spectroscopy and infrared microspectroscopic imaging

Surimi is an intermediate product with an increasing popularity worldwide. Discrimination of impurities like fish bones in surimi has become an urgent issue owing to the food safety and the improved requirements for assessment methods in identification of surimi quality and grades. A Tri-step infrared spectroscopy, including Fourier transform infrared spectroscopy (FT-IR), second derivative infrared spectroscopy (SD-IR) and two-dimensional correlation infrared spectroscopy (2DCOS-IR) has been applied to integrally discriminate different contents (1%-8%) of fish bones in surimi at macro-scale. Meanwhile, attenuated total reflection infrared spectroscopy (ATR-IR) microspectroscopic imaging has been employed to recognize and identify the location of fish bones (less than 1.0 mm in size) in micro-scale. Fishbone characteristic infrared absorption peak at 1011 cm^-1 contributes to surimi peaks at 1045 cm^-1 and 988 cm^-1 confirmed by calculation of their peak heights and ratios of peak areas in original spectra. SD-IR spectra enhance the difference in range of 1440-500 cm^-1, and specifically peak intensity at 599 cm^-1 is significantly increased in surimi with 3%-8% fish bones. Moreover, 2DCOS-IR spectra reveal that surimi containing fish bones have increased intensity of auto-peaks at 525 cm^-1, 519 cm^-1, 512 cm^-1 and 505 cm^-1 mainly contributed by hydroxyapatite and collagen. In ATR-IR microspectroscopic images, a clear fishbone shape (800 × 200 μm) corresponding to its visible image is clearly observed in principal component (PC) score image, which is confirmed as a fish bone by corresponding pixel spectra. Furthermore, the single-wavenumber image shows the spatial chemical distribution of various components for both the fish bone and surimi. Consequently, fish bones can be integrally recognized by physical and chemical imaging manners. It has been demonstrated that the developed Tri-step infrared spectroscopy and ATR-IR microspectroscopic imaging could be applicable for rapidly recognizing impurities and adulterants in surimi.