Jujube extract is commonly used as a food additive and flavoring. The unique jujube aroma and the mild sweet aroma of the extract are critical factors that determine product quality and affect consumer acceptability. The aroma changes with changes in the extraction condition, which is typically dependent on the characteristics of volatile oils in the extract. Despite their importance, the volatile oils of jujube extract have received less attention compared with the soluble components. So, an appropriate qualitative and quantitative method for determination of the volatile oils is vitally important for quality control of the product. A method coupling steam distillation/drop-by-drop extraction with gas chromatography–mass spectrometry (S3DE/GC–MS) was developed to determine the volatile components of jujube extract. Steam distillation was coupled with solvent extraction; the resulting condensate containing volatile components from jujube extract was drop-by-drop extracted using 2 mL of methyl tertiary butyl ether. The solvent served two purposes. First, the solvent extracted the volatile components from the condensate. Second, the volatile components were pre-concentrated by drop-by-drop accumulation in the solvent. As a result, the extraction, separation, and concentration of analytes in the sample were simultaneously completed in one step. The main parameters affecting the S3DE procedure, such as the water steam bubbling rate, extraction solvent volume, sample weight and S3DE time, were optimized. The standard addition approach was essential to obtain accurate measurements by minimizing matrix effects. Good linearity (R2 ≥ 0.9887) and good repeatability (RSDs ≤ 10.35%, n = 5) for 16 analytes in spiked standard analyte samples were achieved. With the S3DE/GC–MS method, seventy-six volatile compounds from jujube extract were identified and the content of 16 compounds was measured. The results were similar to those from simultaneous distillation extraction. The developed method was simple, fast, effective, sensitive, and provided an overall profile of the volatile components in jujube extract. Thus, this method can be used to determine the volatile components of extracts. Graphical abstract The diagram of steam distillation/drop-by-drop extraction device.

The melanoidins produced by the Maillard reaction give foods a golden, brown or black color and release aromatic compounds. Investigating the molecular structure and pyrolysis characteristics of melanoidins provides insight into improving food quality. Seven hydrosoluble colored fractions were isolated from three melanoidins (glycine/glucose (Gly–Glc), proline/glucose (Pro–Glc), and phenylalanine/glucose (Phe–Glc)) using size exclusion and C18 chromatography. Fractions with lower molecular weights (Mw: 5958– 20,106 Da) exhibited deeper colors (browning index: 0.783–3.044). For melanoidins derived from polar amino acids (glycine), low-polarity fractions contributed more to color, while for those from non-polar amino acids (proline), high-polarity fractions were more significant. Mass spectrometry revealed consistent polymerization patterns involving glyoxylic acid and glyoxal across fractions (mass-to-charge differences of 74 m/z and 58 m/z). NMR analysis indicated that Pro–Glc fractions contained more glucose skeletons, whereas Phe–Glc fractions exhibited benzene-ring features. After pyrolysis, furans, pyrroles, and cyclopentenones were major volatiles in Gly–Glc fractions, with pyrroles and DDMP dominating Pro–Glc fractions, and phenyl-containing compounds prevalent in Phe–Glc fractions. These findings suggest amino acids influence both melanoidin structure and glucose-derived skeletons, providing a foundation for controlling color and aroma formation during processing such as baked foods, roasted meats, coffee, dairy products and fermented foods.

An asterisk after the author name Fengyu Bao has been omitted by mistake. The correct version is as follows: Fengyu Bao*aZhikai LiubHaixin BaiaHaiyan ZhangaPengfei Liu*bQidong ZhangcGuobi Chai*ca College of Science, Henan Agricultural University, Zhengzhou 450002, P. R. of China baofengyu@henau.edu.cnb College of Tobacco, Henan Agricultural University, Zhengzhou 450002, P. R. of China liupengfei523@126.comc Zhengzhou Tobacco Research Institute, Zhengzhou 450001, P. R. of China chaigb@ztri.com.cn Synlett 2020, 31, 1501. Publication Date: 09 October 2020 (online) © 2020. Thieme. All rights reserved Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany

Dedicated to Ms. Gailian Xiao A novel and efficient catalyst system was developed for homocoupling reactions of aryl halides. The catalyst system consists of Pd(OAc)₂ and the peppery sensory component of tobacco leaves. This is the first time that a sensory component has been used in an organic reaction. Experiments using the catalyst system showed that the reactions proceeded smoothly under air in the absence of both an additional ligand and a reductant. Furthermore, the catalyst system can be applied to the coupling reactions of hetaryl iodides. Many functional groups (including a hydroxy group) are tolerated.