Headspace Solid-Phase Microextraction GC–MS for Rapid Rice Aroma Analysis Using Optimization Tools

Electronic nose technology for the detection of ergot alkaloid in soft wheat and identification of the relevant volatile compounds by solid phase microextraction/gas chromatography-high resolution Orbitrap-mass spectrometry coupled to chemometrics

Ergot alkaloids (EA) are mycotoxins produced by Claviceps purpurea which commonly infects various cereal species, compromising food safety. This study evaluates the potential of the electronic nose to reliably predict EA contamination in wheat, demonstrating as a proof-of-concept the ability of this technology combined with supervised techniques to distinguish samples contaminated at levels of interest from compliant samples. In particular, the average value of samples correctly classified using PLS-DA was 95.5 %. Furthermore, a volatilomics approach based on HS-SPME/GC-Orbitrap HRMS and chemometrics was successfully applied for the first time to characterize the volatile compound pattern of wheat samples based on the level of EA contamination paying attention to the secondary volatile metabolites. Overall, a high confidence in compound identification was achieved with sub-1 ppm mass accuracy. Unsupervised PCA was used for discrimination purposes, revealing 19 differential compounds (markers), some of which are released during the growth of Claviceps Purpurea fungi.

Evaluating modified atmosphere with variable CO₂-O₂ concentrations for Tribolium castaneum management and quality preservation in Rice storage

This study explored the efficacy of CO₂-MA with variable CO₂-O₂ concentrations (TA: 2 % O₂ + 35 % CO₂, TB: 14 % O₂ + 35 % CO₂, TC: 21 % O₂ + 35 % CO₂, TD: 21 % O₂ + 60 % CO₂) in controlling Tribolium castaneum and preserving rice quality. TD exhibited the highest efficacy, achieving rapid and complete pest mortality within 48 h, particularly in the resilient pupal stage, and nearly 100 % mortality under grain-embedded conditions within 10 days. Quality assessments revealed that TD effectively mitigated lipid oxidation by reducing aldehydes and alcohols, major contributors to rice aging and off-flavors while maintaining acceptable enzymatic activities and VOC profiles. Principal component analysis confirmed that TD minimized oxidative stress and preserved desirable sensory attributes more effectively than hypoxic treatments. These findings presented an advancement in sustainable grain storage, with tailored CO₂-O₂ ratios to achieve desirable outcomes as a sustainable strategy for long-term rice storage.

Research advances in detection of food adulteration and application of MALDI-TOF MS: A review

Food adulteration and illegal supplementations have always been one of the major problems in the world. The threat of food adulteration to the health of consumers cannot be ignored. Food of questionable origin causes economic losses to consumers, but the potential health risks cannot be ignored. However, the traditional detection methods are time-consuming and complex. This review mainly discusses the types of adulteration and technologies used to detect adulteration. Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) is also emphasized in the detection of adulteration and authenticity of origin analysis of various types of food (milk, meat, edible oil, etc.), and the future application direction and feasibility of this technology are analyzed. On this basis, MALDI-TOF MS was compared with other detection methods, highlighting the advantages of this technology in the detection of food adulteration. The future development prospect and direction of this technology are also emphasized.

Analysis of rice characteristic volatiles and their influence on rice aroma

Rice aroma, one of the most important qualities of rice, was the comprehensive result of volatiles in rice and human sense. In this study, the main volatile compounds in rice were analyzed by using gas chromatography-mass spectrometry and gas chromatography-olfactometry, and their correlations with sensory score were investigated. A total of eighty-five volatiles were found in rice samples. By combining odor activity value and correlation analysis, nine volatiles were considered as potential characteristic volatiles in rice aroma, namely hexanal, 2-pentylfuran, octanal, 2-acetyl-1-pyrroline (2-AP), 1-octen-3-ol, trans-2-octenal, decanal, trans-2-nonenal and trans, trans-2,4-decadienal. It was found that the volatiles negatively correlated with sensory scores were positively correlated with hexanal. It indicated that hexanal might be a representative of the negative volatiles of rice aroma. The effects of the nine potential characteristic volatiles on rice aroma were investigated by using sensory analysis. The results showed that the odor intensity and preference level of 2-AP, hexanal, and 1-octen-3-ol were significantly affected by the content. Furthermore, the aroma of cooked rice was significantly different after adding 2-AP, hexanal or trans, trans-2,4-decadienal. Rice aroma was increased by adding 2-AP and deteriorated by adding hexanal or trans, trans-2,4-decadienal, indicating that 2-AP contributed positively to rice aroma while hexanal and trans, trans-2,4-decadienal contributed negatively to rice aroma. Hexanal, 2-AP, and trans, trans-2,4-decadienal were suggested to be the key characteristic volatiles for future aroma evaluation.