Application of advanced molecular spectroscopy and modern evaluation techniques in canola molecular structure and nutrition property research

Effect of Anaerobic Calcium Oxide Alkalization on the Carbohydrate Molecular Structures, Chemical Profiles, and Ruminal Degradability of Rape Straw

To improve the utilization efficiency of rape straw, anaerobic calcium oxide (CaO) alkalization was conducted, and advanced molecular spectroscopy was applied, to detect the internal molecular structural changes. Rape straw was treated with different combinations of CaO (3%, 5%, and 7%) and moisture levels (50% and 60%) and stored under anaerobic conditions. We investigated the carbohydrate chemical constituents, the ruminal neutral detergent fiber (aNDF) and acid detergent fiber (ADF) degradation kinetics, and the carbohydrate molecular structural features. CaO-treated groups were higher (p < 0.05) for ash, Ca, non-fiber carbohydrate, soluble fiber, and the ruminal degradability of aNDF and ADF. In contrast, they were lower (p < 0.05) for the contents of aNDF, ADF, and indigestible fiber. With CaO levels rising from 3% to 7%, the content of aNDF and ADF linearly decreased (p < 0.05). CaO treatment and anaerobic storage changed the molecular characteristics, including structural parameters related to total carbohydrates (TC), cellulosic compounds (CEC), and structural carbohydrates (STC). Alterations in cellulosic compounds' spectral regions were highly correlated with the differences in carbohydrate chemical constituents and the ruminal digestibility of rape straw. In summary, CaO treatment and anaerobic storage altered the molecular structural parameters of carbohydrates, leading to an enhancement in the effective degradability (ED) of aNDF and ADF in rape straw. From the perspective of processing cost and effectiveness, 5% CaO + 60% moisture could be suggested as a recommended treatment combination.

Quantitative analysis of urea in serum by synchronous modulation and demodulation fluorescence spectroscopy

High-precision spectral data is a necessary prerequisite for quantitative analysis of complex solution components. In order to improve the accuracy of spectral data, this paper proposes a method of synchronous modulation and demodulation. This article also combines the "M + N" theory, cleverly uses the excitation fluorescence of the components in the serum and its self-absorption phenomenon, collects the fluorescence spectrum of the serum sample, and then uses the partial least squares (PLS) method and the cubic optimization model method to establish a model to analyze the urea concentration of serum. At the same time, in order to verify the effectiveness of synchronous modulation and demodulation method, the unmodulated fluorescence spectrum is used to establish the regression model of urea concentration. Compared with the unmodulated fluorescence spectrum modeling results, the fluorescence spectrum modeling results after modulation and demodulation have been significantly improved. In the modeling results of fluorescence spectrum after synchronous modulation and demodulation, the Rc is 0.916753, the RMSEC is 2.05848 mmol/L, the Rp is 0.79663, and the RMSEP is 3.16812 mmol/L, the Rp-all is 0.88879, and the RMSEP-all is 2.32114 mmol/L. The results show that the method of synchronous modulation and demodulation proposed in this paper not only reduces the influence of dark current, ambient light and background noise on the signal-to-noise ratio of the spectral data, but also effectively avoids the error caused by the non-synchronization of the chopper and the spectrometer. Therefore, the method used in this paper not only improves the signal-to-noise ratio and accuracy of spectral data, but also improves the accuracy of spectral quantitative analysis of complex solutions.

Effects of maize straw treated with various levels of CaO and moisture on composition, structure, and digestion by in vitro gas production

OBJECTIVE

The objective of this study was to explore the effects of maize straw treated with calcium oxide (CaO) and various moisture, on the composition and molecular structure of the fiber, and gas production by fermentation in an in vitro rumen environment.

METHODS

The experiment used 4×3 Factorial treatment. Maize straws were treated with 4 concentrations of CaO (0%, 3%, 5%, and 7% of dry straw weight) and 3 moisture contents (40%, 50%, and 60%). Scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray fluorescence spectroscopy were employed to measure the surface texture, secondary molecular structure of carbohydrate, and calcium (Ca) content of the maize straw, respectively. The correlation of secondary molecular structures and fiber components of maize straw were analyzed by CORR procedure of SAS 9.2. In vitro rumen fermentation was performed for 6, 12, 24, 48, and 72 h to measure gas production.

RESULTS

Overall, the moisture factor had no obvious effect on the experimental results. Neutral detergent fiber (NDF), acid detergent fiber, acid detergent lignin, hemicellulose and cellulose contents decreased (p<0.05) with increasing concentrations of CaO treatment. Surface and secondary molecular structure of maize straw were affected by various CaO and moisture treatments. NDF had positive correlation (p<0.01) with Cell-H (H, height), Cell-A (A, area), CHO-2-H. Hemicellulose had positive correlation (p<0.01) with Lignin-H, Lignin-A, Cell-H, Cell-A. Ca content of maize straw increased as the concentration of CaO was increased (p<0.01). Gas production was highest in the group treated with 7% CaO.

CONCLUSION

CaO can adhere to the surface of the maize straw, and then improve the digestibility of the maize straw in ruminants by modifying the structure of lignocellulose and facilitating the maize straw for microbial degradation.