Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

Spectroscopic methods deliver a valuable non-destructive analytical tool that provides simultaneous qualitative and quantitative characterization of various samples. Apples belong to the world’s most consumed crops and with the current challenges of climate change and human impacts on the environment, maintaining high-quality apple production has become critical. This review comprehensively analyzes the application of spectroscopy in near-infrared (NIR) and visible (Vis) regions, which not only show particular potential in evaluating the quality parameters of apples but also in optimizing their production and supply routines. This includes the assessment of the external and internal characteristics such as color, size, shape, surface defects, soluble solids content (SSC), total titratable acidity (TA), firmness, starch pattern index (SPI), total dry matter concentration (DM), and nutritional value. The review also summarizes various techniques and approaches used in Vis/NIR studies of apples, such as authenticity, origin, identification, adulteration, and quality control. Optical sensors and associated methods offer a wide suite of solutions readily addressing the main needs of the industry in practical routines as well, e.g., efficient sorting and grading of apples based on sweetness and other quality parameters, facilitating quality control throughout the production and supply chain. This review also evaluates ongoing development trends in the application of handheld and portable instruments operating in the Vis/NIR and NIR spectral regions for apple quality control. The use of these technologies can enhance apple crop quality, maintain competitiveness, and meet the demands of consumers, making them a crucial topic in the apple industry. The focal point of this review is placed on the literature published in the last five years, with the exceptions of seminal works that have played a critical role in shaping the field or representative studies that highlight the progress made in specific areas.

DOI： 10.3390/foods12101946

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Authorship：Lead author   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Abstract

Raman spectra of water and supercooled water were measured in the temperature range of −6 to 18°C with every 2°C step. The obtained spectra were analyzed for the 3750–2850 and 400–100 cm⁻¹ regions by two‐dimensional correlation (2D‐COS) Raman spectroscopy. As previously reported, there are three bands at around 3620, 3420, and 3200 cm⁻¹ in the OH‐stretching region. These bands were assigned to the OH‐stretching modes of dangling (Dang) bonds of water, destructured, and structured water species, respectively. A pair of clear peaks appear in asynchronous 2D‐COS maps in the 3750–2850 cm⁻¹ region of Raman spectra of water developed using the spectra measured in the temperature ranges of −6 to 2°C, 0 to 8°C, and 8 to 18°C, and they are similar to each other, suggesting nonlinear (convex) temperature‐dependent increase and decrease of the two kinds of water species. A power spectrum calculated along the diagonal line in the synchronous spectrum in the −6 to 18°C range has a peak at 3171 cm⁻¹ with a broad shoulder at around 3400 cm⁻¹. These peaks at 3171 and 3400 cm⁻¹ may be assigned to the collective mode and its local mode of structured water, respectively. In the 400–100 cm⁻¹ region, there is a broad feature centered at 185 cm⁻¹ assigned to the intermolecular stretching mode of water molecule. Close inspection of the low‐frequency region by the baseline corrected spectra and the second derivative spectra shows that the broad feature consists of a major band at around 185 cm⁻¹ and a weak shoulder at around 150 cm⁻¹. We have assigned these two peaks at 185 and 150 cm⁻¹ to the structured and destructured water, respectively, based on the results of 2D‐COS and the comparison with the results of multivariate curve resolution‐alternative least squares reported by Hamaguchi et al. A hetero 2D correlation synchronous map between the 3750–3000 and 400–100 cm⁻¹ regions reveals that there is a cross peak between the structured water band at around 3200 cm⁻¹ and the 185 cm⁻¹ band, confirming that the 185 cm⁻¹ band comes from the structured water.

DOI： 10.1002/jrs.6444

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Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/jrs.6444

Authorship：Lead author   Publisher：AIP Publishing  

DOI： 10.1063/5.0071893

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Other Link： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-21K05013/

Publisher：Wiley  

DOI： 10.1002/9783527830312.ch6

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Authorship：Lead author   Language：English   Publisher：The Japan Society for Analytical Chemistry  

Attenuated total reflectance–far ultraviolet (ATR-FUV) spectra of Li⁺ and polyether ligands, such as glymes and poly (ethylene glycol) (PEG), in solution give information about changes in the electronic states of the ligands. From the ATR-FUV spectra, the coordination numbers between Li⁺ and monoglyme, diglyme, triglyme, and PEG400 were determined to be 4, 5, 6, and 5, respectively. Our results indicate that Li⁺ is coordinated only by the ligands rather than its counter-ions.

DOI： 10.2116/analsci.19c011

DOI： 10.1039/d0cp03865b_references_DOI_Fow4PRZmf8rygqweelJLkFZIpO6

PubMed

CiNii Article

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Other Link： https://link.springer.com/article/10.2116/analsci.19C011/fulltext.html

Authorship：Lead author   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acs.jpca.9b09274

DOI： 10.3175/molsci.14.a0114_references_DOI_JD6ZusM7OHffgvMiPGH0tTpY9ZB

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Publisher：AIP Publishing  

DOI： 10.1063/1.5111288

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Other Link： https://kaken.nii.ac.jp/grant/KAKENHI-PLANNED-17H06445/

Publishing type：Research paper (scientific journal)  

© 2019 Institute for Low Temperature Physics and Engineering. All rights reserved. The A-X transition of diatomic bismuth, Bi2, was revisited by laser induced fluorescence in solid Ne at 3 K. Molecular constants, i.e., vibrational frequencies of 137 cm-1 and 174 cm-1, were reproduced for the upper and lower electronic states as reported by Bondybey et al. [Chem. Phys. Lett. 76, 30 (1980)]. Two-dimensional mapping of emission spectra confirmed satellite bands in higher and lower excitation/emission energies for each of the major bands in the vibrational progression of v′-v″ (v′ = 0.5, v″ = 5-12). Based on the molecular orbital cal-culations, presence of clusters, Bi2Nen (n = 1-6), is proposed for possible carriers of the observed satellites. For the relatively large matrix shift of ∼ 67 cm-1 in solid Ne for the term energy of the A state, the diatomic bismuthis supposed to exist as a linearly coordinated cluster of Bi2Ne in the matrix.

Scopus

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Publisher：Elsevier BV  

DOI： 10.1016/j.saa.2018.01.042

DOI： 10.2116/analsci.19c011_references_DOI_SuFwlR3NHc6q8DPhQBwzRCY6rmQ

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