Impaired Sensitivity to Thyroid Hormones is Associated with Mild Cognitive Impairment in Euthyroid Patients with Type 2 Diabetes.

Purpose: The prevalence of mild cognitive impairment (MCI) in patients with type 2 diabetes (T2D) is rapidly increasing. Thyroid hormones are key regulators of cognitive function in adults. The purpose of this study was to investigate the relationship between thyroid hormone sensitivity and MCI in euthyroid T2D patients. Patients and Methods: A total of 400 euthyroid T2D patients were enrolled in this cross-sectional study, including 218 patients with normal cognition and 182 MCI patients. The Montreal Cognitive Assessment (MoCA) was used to evaluate cognitive function. The free triiodothyronine to free thyroxine (FT3/FT4) ratio was calculated as a measure of peripheral sensitivity to thyroid hormones; the thyroid-stimulating hormone index (TSHI), thyrotrophic thyroxine resistance index (TT4RI) and thyroid feedback quantile-based index (TFQI) were calculated as measures of central sensitivity to thyroid hormones. Linear regression analysis and logistic regression analysis were performed to explore the relationships between these indices of thyroid hormone sensitivity and the MoCA score and MCI, respectively. Results: Compared with the normal cognitive function group, patients in the MCI group had higher TSHI, TT4RI and TFQI but a lower FT3/FT4 ratio (P<0.05). The MoCA score was positively correlated with the FT3/FT4 ratio but negatively correlated with TSHI, TT4RI and TFQI (P< 0.05). Multivariate logistic regression analysis showed that a low FT3/FT4 ratio and high TSHI, TT4RI and TFQI were independently associated with MCI (P<0.05). After adjustment for confounding factors, the odds ratio (OR) for the association between MCI and the highest tertile of the FT3/FT4 was 0.455 (95% CI: 0.264-0.785), for the highest tertile of TSHI, the OR was 2.380 (95% CI: 1.376-4.119), for the highest tertile of TT4RI, the OR was 2.342 (95% CI:1.353-4.054), and for the highest tertile of TFQI, the OR was 2.536 (95% CI: 1.466-4.387) (P< 0.05). Conclusion: Impaired sensitivity to thyroid hormones is associated with MCI in euthyroid T2D patients.

Direct Identification and Quantitation of Protein Peptide Powders Based on Multi-Molecular Infrared Spectroscopy and Multivariate Data Fusion.

Given that protein peptide powders (PPPs) from different biological sources were inherited with diverse healthcare functions, which aroused adulteration of PPPs. A high-throughput and rapid methodology, united multi-molecular infrared (MM-IR) spectroscopy with data fusion, could determine the types and component content of PPPs from seven sources as examples. The chemical fingerprints of PPPs were thoroughly interpreted by tri-step infrared (IR) spectroscopy, and the defined spectral fingerprint region of protein peptide, total sugar, and fat was 3600-950 cm-1, which constituted MIR finger-print region. Moreover, the mid-level data fusion model was of great applicability in qualitative analysis, in which the F1-score reached 1 and the total accuracy was 100%, and a robust quantitative model was established with excellent predictive capacity (Rp: 0.9935, RMSEP: 1.288, and RPD: 7.97). MM-IR coordinated data fusion strategies to achieve high-throughput, multi-dimensional analysis of PPPs with better accuracy and robustness which meant a significant potential for the comprehensive analysis of other powders in food as well.

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), rp 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.

Taste compounds generation and variation of broth in pork meat braised processing by chemical analysis and an electronic tongue system.

The aim was to unveil the generation and variation rule of the main taste components in braised broth for 10 quantitative repeated braising cycles. The major taste compounds of three groups (MS, broth cooked with meat and spices; M, broth cooked with meat; and S, broth cooked with spices) were systematically analyzed by the state-of-art chromatography and electronic sensory technology. As braising cycles progressed, contents of free 5'-nucleotides and amino acids were increased in MS and M, while those nucleotides were not detected in S. A significant discrimination of taste in MS and M was revealed by electronic tongue evaluation during the process. As the formation rates (FR) of taste compounds and the transformation rates (TR) of taste compounds to volatile compounds were mainly accounting for the generation and variation of flavor in broth, a hypothesis was proposed to illustrate the whole variation of taste compounds in the process integrally that the ratio of FR/TR dividing the process into three stages, Degradation, Balance, and Accumulation. PRACTICAL APPLICATIONS: The traditional braising process and formula are empirical and extensive, which impede the increase in meat products output. Nowadays, the industry of braising products is facing a problem of standardization and quality control, and needs to carry out scientific and quantitative process improvement efficiently. Therefore, the developed comprehensive approach demonstrates great potential for braised meat broth flavor monitoring and quality control in an objective and holistic manner. It provides data support and new ideas of technology development for quality control in the process of meat braising.

Hydroxyapatite From the Skull of Tuna (Thunnus obesus) Head Combined With Chitosan to Restore Locomotive Function After Spinal Cord Injury.

Hydroxyapatite is an important fish bone calcium in tuna head, which is widely used to repair of bone defect. Chitosan is a degradable basic polysaccharide with good biocompatibility and bone guiding, which can achieve targeted delivery to the injured spinal cord after spinal cord injury (SCI). This study aimed to evaluate the beneficial effects of chitosan combined hydroxyapatite (chitosan-hydroxyapatite) nanoparticles on SCI. The result revealed the chitosan-hydroxyapatite particles were successfully constructed and the stability of particles was maintained at low temperature. Moreover, we found chitosan-hydroxyapatite administration could improve SCI, while chitosan alone treatment resulted in no significant increase of the Basso Beattie Bresnahan (BBB) scores compared with the control group. In addition, chitosan-hydroxyapatite particles also significantly reduced the lesion cavity volume and improved the dispersed structure, indicating it could promote the recovery of tissue function of SCI rats. This study explored the effects of chitosan-hydroxyapatite nanoparticles on the location and function of spinal cord injury, provided experimental evidence for further research on its application in spinal cord repair, and helped improve the efficient use of tuna heads.

Direct identification and quantitation of fluorescent whitening agent in wheat flour based on multi-molecular infrared (MM-IR) spectroscopy and stereomicroscopy.

Fluorescent brighteners, illegally used to whitening wheat flour, are detrimental to people health. The aim was to establish a rapid and direct method to identify and quantify fluorescent whitening agent OB-1 (FWA OB-1) in wheat flour by using multi-molecular infrared (MM-IR) spectroscopy combined with stereomicroscopy. Characteristic peak profile of FWA OB-1 used as a judgment basis was spatially revealed by stereomicroscopy with group-peak matching of MM-IR at 1614 cm-1, 1501 cm-1 and 893 cm-1 and were further unveiled by the second derivative infrared spectroscopy (SD-IR) and its two-dimensional correlation infrared (SD-2DCOS IR) spectroscopy for higher resolution, and were validated by high-performance liquid chromatography (HPLC). Moreover, a quantitative prediction model based on IR spectra was established by partial least squares 1 (PLS1) (R2, 98.361; SEE, 5.032; SEP, 5.581). The developed method was applicable for rapid and direct analysis of FWA OB-1 (low to 10 ppm) in flour with relative standard deviation (RSD) of 5%. The capabilities of MM-IR with spectral qualitative and quantitative analysis would be applicable to direct identification and quantitation of fluorescent whitening agents or other IR-active compounds in powder objects.

Micro-nano particle formation and transformation mechanisms of broth in meat braised processing.

The formation and transformation mechanisms of micro-nano particles (MNPs) in broth during meat braising were systematically investigated through a sophisticated controlled process. Dynamic changes in the morphology, composition and spatial distribution of MNPs were comprehensively characterized, and subsequently the mechanisms were visually uncovered from microcosmic-spatial perspectives. MNPs formed as circular-shape colloidal systems with an aggrandizing tendency for particle number and size and gradually stabilize eventually. Specifically, the major MNPs gradually increased the size from <400 nm to ~1500 nm and accumulated triglycerides and glycoconjugates resulting from lipid oxidation, Maillard reaction, etc. Continuous formation of MNPs in broth progressively facilitated the spatial coalescence and self-assembly of free substances driven by intermolecular interactions, and consequently principal nutrients and flavor compounds further accumulated in the MNPs by the braising process. Hence, this work not only revealed the MNP formation and transformation mechanisms but offered a foundation for investigating MNP-dependent effect on broth flavor.

Odor characteristics of white croaker and small yellow croaker fish during refrigerated storage.

White croaker and small yellow croaker both belong to the fish family Sciaenidae, but their economic value and odor characteristics are quite different. In this study, electronic nose and gas chromatography-mass spectrometry were utilized to explore the odor characteristics of the two stored for different refrigeration periods. The results showed that their odor profiles could be clearly distinguished by principal component analysis. Compounds associated with fresh white croaker were found to be more complex than smaller yellow croaker through the load graph, while the result was opposite in later cold storage. The absolute peak areas of compounds like trimethylamine and 3-methyl-butanol were 6.42 and 1.42, respectively, in the white croaker, which were higher than in the small yellow croaker at the first day of refrigeration. And compound such as indole was first produced in white croaker during late cold storage. However, there were more compounds related to spoilage in the small yellow croaker; compounds like phenylethyl alcohol and benzeneacetaldehyde were not detected in the white croaker. PRACTICAL APPLICATIONS: White croaker and small yellow croaker are almost indistinguishable in appearance, especially after being cooked. But there are vast differences in their meat quality and odor characteristics, which affect their commercial values. As a result, a lot of white croakers are dyed and sold as small yellow croakers, although this does not change their eating or odor qualities. Principal component analysis of the odor characteristics of the two species of fish stored for different periods of refrigeration might provide some scientific basis for exploring the causes of their economic value differences.

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.

Identification of important odorants derived from phosphatidylethanolamine species in steamed male Eriocheir sinensis hepatopancreas in model systems.

Flavor is critical to the commercial acceptance of the highly valued Chinese mitten crab (Eriocheir sinensis). This study investigated the important odorants (IOs) in male E. sinensis hepatopancreas formed from phosphatidylethanolamine (PE) in model systems. A total of fifteen IOs were detected by gas chromatography-mass spectrometry-olfactometry (GC-MS-O). Among the IOs that were also detected as oxidation products of PE extract were hexanal, heptanal, nonanal, 2-pentylfuran and 2-octanone, and the optimized oxidation conditions of PE extract were 175 °C for 60 min. For further analysis, nine PE species were considered important precursors of IOs in E. sinensis. Odorants derived from PE (16:0/18:2), PE (18:0/18:2), PE (18:0/20:4), PE (16:0/22:6), and PE (18:0p/22:6) specie standards were detected, and their oxidative stabilities are discussed. These findings are important for understanding the comprehensive formation mechanism of IOs in E. sinensis, which may provide theoretical guidance for improving the overall flavor of aquatic products.

Effect of heat extraction on water-soluble taste substances in processing products of chilled large yellow croaker (Pseudosciaena crocea).

In this paper, we analyzed the umami amino acids composition and content in minced meat (MM), fish head meat (HM), and fish roe (R). According to different ratios of material to liquid, we extracted water-soluble taste substances from the three materials and then compared composition and content of the umami amino acids and taste nucleotides in the different water-soluble taste substances. Finally, we analyzed Taste Activity Value (TAV) and the Equivalent Umami Concentration (EUC) between umami amino acids and taste nucleotides. The results showed that umami amino acids total content in MM, HM, and R samples were, respectively, 50.63 mg/100 g, 41.95 mg/100 g, and 67.06 mg/100 g. When the water-soluble taste substances extracted from the above samples were in the "D" state (MM), the "C" state (HM), and the "C" state (R), respectively, the umami amino acid content could be comparable to the original sample. And the highest EUCs were respectively 1.37 g MSG/100 g, 0.87 g MSG/100 g, and 0.49 g MSG/100 g (MSG: Sodium Glutamate). To some extent, the results of this study indicated that the water-soluble taste substances could be equivalent to the original sample and could be further applied as a taste regulator in some respects.

A rapid analytical and quantitative evaluation of formaldehyde in squid based on Tri-step IR and partial least squares (PLS).

Formaldehyde abuse for retaining squid freshness is detrimental to public health. The aim is to establish a rapid and quantitative detection method of formaldehyde in squid for screening massive samples. A linear relationship between formaldehyde concentration in squid and formaldehyde concentration in squid soaked water was observed using HPLC. Chemical profile variances of squids were rapidly analyzed by Tri-step infrared spectroscopy. Specifically, with increasing formaldehyde concentration, peak intensities of 2927cm-1 (vas(CH2)), 1081cm-1 (glycogen), 1631cm-1 (ß-sheet proteins) decreased while 1655cm-1 (α-helix proteins) increased. Spectral curve-fitting results further disclosed that ß-sheet proteins were transformed to α-helix and ß-turn conformations. Furthermore, a quantitative prediction model based on IR spectra was established by PLS (R2, 0.9787; RMSEC, 5.51). The developed method was applicable for rapid (c.a. 5min) and quantitative analysis of formaldehyde in squids with LOD of 15mg/kg.

Comparison of Gender Differences in Nutritional Value and Key Odor Profile of Hepatopancreas of Chinese Mitten Crab (Eriocheir Sinensis).

The nutritional value and key odor profile of hepatopancreas of Chinese mitten crab (Eriocheir sinensis) was evaluated, and gender differences in terms of edible yield, proximate composition, different lipid fractions, fatty acid composition, and key odor compounds were compared. Total lipids were separated into different lipid fractions using silicic acid columns. And odorants were detected by monolithic material sorptive extraction coupled with gas chromatography-mass spectrometry-olfactometry (GC-MS-O). Furthermore, detected frequency and odor intensity method of GC-O were applied to select key odor compounds in steamed E. sinensis. The results showed male crabs (34.06%) had a higher edible yield than female crabs (32.42%). Hepatopancreas was the most abundant portion in both genders, which contained high lipid content. Higher contents of triacylglycerols, sterols, free fatty acids, and phosphatidylethanolamine in female crabs resulted in a significant higher total lipid content in females (40.05%) than in males (37.94%). Meanwhile, total monounsaturated fatty acids and polyunsaturated fatty acids of female crabs had significant higher content than male crabs, and the ratio of docosahexaenoic acid to eicosapentaenoic acid of female crabs (1.26) showed higher value than male crabs (1.18), which indicated that female crabs had higher nutritional value than male crabs. For further analyses, unique odor compounds detected in female crabs showed a plant/vegetable-like odor, while sweety, corn-like odor in male crabs. These suggested that hepatopancreases of female crabs are healthier than male crabs for human consumption, however, they may be favored by different consumers individually due to their unique aroma profiles.

Rapid determination and chemical change tracking of benzoyl peroxide in wheat flour by multi-step IR macro-fingerprinting.

BPO is often added to wheat flour as flour improver, but its excessive use and edibility are receiving increasing concern. A multi-step IR macro-fingerprinting was employed to identify BPO in wheat flour and unveil its changes during storage. BPO contained in wheat flour (<3.0 mg/kg) was difficult to be identified by infrared spectra with correlation coefficients between wheat flour and wheat flour samples contained BPO all close to 0.98. By applying second derivative spectroscopy, obvious differences among wheat flour and wheat flour contained BPO before and after storage in the range of 1500-1400 cm(-1) were disclosed. The peak of 1450 cm(-1) which belonged to BPO was blue shifted to 1453 cm(-1) (1455) which belonged to benzoic acid after one week of storage, indicating that BPO changed into benzoic acid after storage. Moreover, when using two-dimensional correlation infrared spectroscopy (2DCOS-IR) to track changes of BPO in wheat flour (0.05 mg/g) within one week, intensities of auto-peaks at 1781 cm(-1) and 669 cm(-1) which belonged to BPO and benzoic acid, respectively, were changing inversely, indicating that BPO was decomposed into benzoic acid. Moreover, another autopeak at 1767 cm(-1) which does not belong to benzoic acid was also rising simultaneously. By heating perturbation treatment of BPO in wheat flour based on 2DCOS-IR and spectral subtraction analysis, it was found that BPO in wheat flour not only decomposed into benzoic acid and benzoate, but also produced other deleterious substances, e.g., benzene. This study offers a promising method with minimum pretreatment and time-saving to identify BPO in wheat flour and its chemical products during storage in a holistic manner.

[Applied Research in Grade Estimation of Surimi by Near Infrared Spectroscopy].

The feasibility of utilizing near infrared spectroscopy for estimating frozen and thawed white croaker surimi with different grades was presented in the research. First-derivative and standard normal variable transformation were used as pretreatment method, then principal component analysis was carried out on the processed datas. Establish grade estimation model on white croaker surimi with different grades by principal component analysis-mahalanobis distance pattern recognition method. Seven kinds of physicochemical indexes (moisture, protein, crude fat, salt-soluble protein, gel strength, water-holding ability and whiteness) of white croaker surimi with different grades were determinated. We came to the following conclusions. Firstly, white croaker surimi with three grade could be distinguished effectively by principal component analysis. Secondly, the model of grade estimation established by principal component analysis-mahalanobis distance pattern recognition method had better performance on frozen white croaker surimi than thawed ones, the former's comprehensive accuracy was 96. 3 % with the latter's is 83. 3%. Thirdly, the physicochemical indexes of white croaker surimi with different grades had some distinctions. The research indicated that near infrared spectroscopy could estimate the grade of white croaker surimi rapidly and nondestructively.

Rapid discrimination of three marine fish surimi by Tri-step infrared spectroscopy combined with Principle Component Regression.

A Tri-step infrared spectroscopy (Fourier transform infrared spectroscopy (FT-IR) integrated with second derivative infrared (SD-IR) spectroscopy and two-dimensional correlation infrared spectroscopy (2DCOS-IR)) combined with Principal Component Regression (PCR) were employed to characterize and discriminate three marine fish surimi (white croaker surimi (WCS), hairtail surimi (HS) and red coat surimi (RCS)). The three surimi had similar IR macro-fingerprints (similarity>0.7) especially for the absorption bands of amide groups. Compared to the other two surimi, however, RCS had a middle strong characteristic peak of lipids at 1745 cm(-1), indicating that RCS had the highest content of lipids. SD-IR spectra of the three surimi enhanced the spectral resolution and amplified the small differences, especially at about 1682 cm(-1), 1679 cm(-1), 1656 cm(-1) and 1631 cm(-1), suggesting that the three had different profiles of proteins. Moreover, evident differences were observed in 2DCOS-IR spectra of 1500-1800 cm(-1). WCS had one strong (1620 cm(-1)) and three weak auto-peaks (1520 cm(-1), 1552 cm(-1), 1706 cm(-1)). HS had three strong (1621 cm(-1), 1648 cm(-1), 1708 cm(-1)) and two weak auto-peaks (1523 cm(-1), 1553 cm(-1)), whereas RCS had one strong (1623 cm(-1)) and three weak auto-peaks (1525 cm(-1), 1709 cm(-1), 1738 cm(-1)). Furthermore, sixty batches of surimi (twenty for each surimi) were objectively classified by PCR. It was demonstrated that the Tri-step infrared spectroscopy combined with PCR could be applicable for discrimination of precious marine fish surimi in a direct, rapid and holistic manner.

[Study on freshness evaluation of ice-stored large yellow croaker (Pseudosciaena crocea) using near infrared spectroscopy].

Near infrared spectroscopy (NIR) was used in this experiment to evaluate the freshness of ice-stored large yellow croaker (Pseudosciaena crocea) during different storage periods. And the TVB-N was used as an index to evaluate the freshness. Through comparing the correlation coefficent and standard deviations of calibration set and validation set of models established by singly and combined using of different pretreatment methods, different modeling methods and different wavelength region, the best TVB-N models of ice-stored large yellow croaker sold in the market were established to predict the freshness quickly. According to the research, the model shows that the best performance could be established by using the normalization by closure (Ncl) with 1st derivative (Dbl) and normalization to unit length (Nle) with 1st derivative as the pretreated method and partial least square (PLS) as the modeling method combined with choosing the wavelength region of 5 000-7 144, and 7 404-10 000 cm(-1). The calibration model gave the correlation coefficient of 0.992, with a standard error of calibration of 1.045 and the validation model gave the correlation coefficient of 0.999, with a standard error of prediction of 0.990. This experiment attempted to combine several pretreatment methods and choose the best wavelength region, which has got a good result. It could have a good prospective application of freshness detection and quality evaluation of large yellow croaker in the market.

[Application of near infrared spectroscopy technique based on support vector machine in the measurement of moisture and protein contents in Surimi].

Near infrared spectroscopy calibration models for moisture and protein contents of surimi were established by support vector machine (SVM), and predicted by independent sample set. The spectra processed by first derivative gap two (DB1G2), standard normal variation (SNV) and multiplicative scatter correction (MSC), then compressed by partial least squares (PLS), and the first fifteen were taken as variables. The correlation coefficient of calibration (Rc), correlation coefficient of validation (Rv), standard error of calibration (SEC) and standard error of prediction(SEP) of moisture model were 0.97, 0.95, 0.53 and 0.58, respectively. The Rc, Rv, SEC and SEP of protein model were 0.99, 0.98, 0.36 and 0.39, respectively. The two models had good recurrence. Therefore, NIR spectroscopy based on SVR can be applied to rapidly predict moisture and protein contents in surimi.

Isolation and identification of flavour peptides from Puffer fish (Takifugu obscurus) muscle using an electronic tongue and MALDI-TOF/TOF MS/MS.

To clarify the key flavour peptides that account for the cooked taste of puffer fish, this study was performed to examine flavour peptides extracted from the flesh of puffer fish (Takifugu obscurus). Peptides fractions (P1, P2, P3, P4 and P5) were purified from an aqueous extract of T. obscurus muscle by ultrafiltration and Sephadex G-15 gel filtration chromatography (GFC). P2 was further fractionated into P2a, P2b, and P2c by reverse phase high performance liquid chromatography (RP-HPLC). Fraction P2b elicited umami and sweet taste. The amino acid sequence of P2b subfraction was identified as Tyr-Gly-Gly-Thr-Pro-Pro-Phe-Val (836.4Da) by matrix-assisted laser desorption/ionisation time of flight mass spectrometry (MALDI-TOF/TOF MS/MS). Hydrophilic amino acids residues Tyr, Gly, Gly, Thr, and Phe are likely to contribute to the umami and sweet taste of this octapeptide. The results of this study suggest this peptide is one of important components of the 'mellowness' and 'tenderness' taste of the T. obscurus.