Just-in-Time Learning-Integrated Partial Least-Squares Strategy for Accurately Predicting 71 Chemical Constituents in Chinese Tobacco by Near-Infrared Spectroscopy.

Near-infrared spectroscopy has been widely used to characterize the chemical composition of tobacco because it is fast, economical, and nondestructive. However, few predictive models perform ideally when applied to large spectral libraries of tobacco and its various chemical indicators. In this study, the just-in-time learning-integrated partial least-squares (JIT-PLS) modeling strategy was applied for the first time to quantitatively analyze 71 chemical components in Chinese tobacco. Approximately 18000 tobacco samples from China were analyzed to find appropriately similar measurements and propose suitable and flexible similar subsets from the calibration for each test sample. In total, 879 representative aged tobacco leaf samples and 816 cigarette samples were used as external instances to evaluate the practical predicting ability of the proposed method. The most suitable similar subsets for each test sample could be selected by limiting the Euclidean distance and number of similar subsets to 0-3.0 × 10-9 and 10-300, respectively. The majority of the JIT-PLS models performed significantly better than traditional PLS models. Specifically, using JIT-PLS instead of traditional PLS models increased the R 2 values from 0.347-0.984 to 0.763-0.996, and from 0.179-0.981 to 0.506-0.989 for the prediction of 67 and 71 components in aged tobacco leaf and cigarette samples, respectively. Good prediction ability was demonstrated for routine chemical components, polyphenolic compounds, organic acids, and other compounds, with the mean ratios of prediction to deviation (RPDmean) being 7.74, 4.39, 4.05, and 5.48, respectively). The proposed methodology could simultaneously determine 67 major components in large and complicated tobacco spectral libraries with high precision and accuracy, which will assist tobacco and cigarette quality control in collecting as well as processing stages.

Plant exine capsules based encapsulation strategy: A high loading and long-term effective delivery system for nobiletin.

The properties of high loading capacity and long-term absorption are of great significance in the field of nutraceuticals or drugs delivery. Herein, we developed an innovative method to achieve these expected effects using plant exine capsules, a kind of natural pollen grains, which could provide large internal cavities for loading and robust exine against harsh conditions. In our work, we firstly made a soluble mixture of glycerol monostearate (GM) and nobiletin (NOB) inside the cavities of plant exine capsules by ultrasound with high temperature to obtain a supersaturated state of NOB, which could be characterized by XRD, DSC and FTIR. After that, the loaded capsules were cooled to room temperature. Alginate hydrogels were then selected for encapsulating and further controlling NOB release in simulated gastric and intestinal conditions. As a result, it demonstrated that our approach was able to reach an extremely high NOB loading capacity of 770 ±â€¯40 mg/g using sunflower pollen grains (SPGs). Meanwhile, the existence of GM, SPGs and alginate hydrogels all retarded the release of the NOB synergistically, thus taking a slow release effect in the stomach while a long-term effective absorption in the intestine. Taken together, our processing method of encapsulating hydrophobic nutraceuticals provides an important insight for broadening the applications of nutraceutical or drug encapsulation and delivery.

Leveraging plant exine capsules as pH-responsive delivery vehicles for hydrophobic nutraceutical encapsulation.

Plant exine capsules are natural microscale capsules that are highly physically robust and chemically resilient. They are extracted from pollen grains and plant spores, and can be used as renewable and safe microcapsules for encapsulation applications. Herein, we report the successful evacuation of natural sunflower pollen grains (SPGs) and Lycopodiastrum casuarinoides spore exine capsules (SECs) and investigated the effects of different loading methods on the encapsulation and release of nobiletin, a model hydrophobic nutraceutical. The compositional and morphological characterizations of SPGs and SECs obtained by the developed extraction protocol confirmed that the inside contents had been removed and hollow pollen cavities were obtained successfully. In addition, coumarin-6, a hydrophobic fluorescent probe, was encapsulated into SPGs and SECs, which proved the possibility of using them to encapsulate hydrophobic nutraceuticals. Furthermore, controlled release in simulated digestive fluids (SDF) was achieved by coating calcium alginate onto the outside of the SPGs and SECs. Looking forward, this may provide an effective and potential delivery model to protect loads from degradation in the stomach and achieve pH-responsive delivery of hydrophobic nutraceuticals after oral administration.