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Fried pepper oil (FPO) is a widely used flavoring oil in China, but it suffers from complex chemical reactions that give an unpleasant odor. The aim of this paper is to study the main causes of off-flavor in FPO, as well as identify key off-flavor compounds in FPO. Fifty-eight volatiles were identified using HS-SPME–GC–MS (headspace solid-phase microextraction–gas chromatography–mass spectrometry) during storage. Fifteen off-flavor compounds were initially targeted by odor activity values (OAVs) calculations and partial least squares regression (PLSR) analysis. Eventually, five key off-flavor compounds were identified by recombination experiments and omission test, which were hexanal, (E) - 2-octenal, terpinyl acetate, α -terpineol, and hexanoic acid. The off-flavors could derive from the oxidative degradation of long-chain fatty acids and the acid-catalyzed rearrangement of terpenes. The results of the study provide a theoretical basis for the regulation of off-flavor in FPO and a practical guide for the industrial production of FPO. [Display omitted] • Five odorants with off-flavor have been identified as markers of flavor damage. • Off-flavor of FPO was most related to aldehydes and alcohols. • Oxidative cleavage of long-chain fatty acids could be a main source of off-flavor. • Terpene degradation could be lead to flavor attenuation. [ABSTRACT FROM AUTHOR]

Sea cucumber Apostichopus japonicus Selenka, as a traditional tonic, has great edible value and a large-scale aquaculture variety in China. As its spawn has similar nutrients as body wall, residents in many countries often use spawn to make various delicious food, especially Japanese ferment it to make sauce. In this study, four new triterpene glycosides (1 - 4) together with a known holotoxin B (5) were obtained from it. New compounds were holotoxin S 1 -S 3 (1 - 3) with rare 18(16)-lactone ring as well as holotoxin S 4 (4) with an 18(20)-lactone group belonging to holostane type. Holotoxin B was firstly isolated from spawn of A. japonicus. The structures of four new molecules were elucidated based on extensive spectroscopic analysis and chemical tools. • Four new compounds were obtained in this paper. • Rare lactone ring produced by sea cucumber spawn. • Saponins differ in body wall and spawn. • First report on chemical constituents in sea cucumber spawn. [ABSTRACT FROM AUTHOR]

• PTA quantified after extraction from P. aquilinum in nearly anhydrous medium. • 2. First comparative study on PTA content in P. aquilinum from different places in China. Ptaquiloside (PTA) is a carcinogenic norsesquiterpene glucoside existing in Pteridium aquilinum, the young fronds of which are widely used as a wild vegetable in China. To ensure food safety, it is extremely important to establish a fast and accurate method for the quantification of PTA in P. aquilinum. This paper aimed to establish a qualification and quantification method for PTA in P. aquilinum based on a solid-phase extraction (SPE) pre-concentrating technique followed by TOF-MS/MS and HPLC-DAD analysis. The results showed that the developed method can qualify and quantify the PTA in P. aquilinum with an average recovery of 87.0% for PTA. The method is repeatable extra- and inter- days, with RSD values lower than 5%. A total of 18 P. aquilinum samples from different places of China were analyzed by the established method. The contents of PTA in the investigating samples varied from 5.61 ± 0.50–4250 mg kg−1 in dry weight, which was mostly lower than those of cases reported abroad. This study presents the characterization and quantitative assay of PTA in P. aquilinum from different places of China using direct TOF-MS/MS and HPLC-DAD quantification combined with solid-phase extraction (SPE) pre-concentrating technique, which can be employed for the safety evaluation of the food derived from P. aquilinum. [ABSTRACT FROM AUTHOR]