Effect of the Consolidation Level on Organic Volatile Compound Emissions from Maize during Storage

Abstract

The aim of this study was to determine the emission of organic volatile compounds from maize grain as a function of granularity and packing density of bulk material in conditions imitating processes occurring in silos. The study was carried out with the use of a gas chromatograph and an electronic nose, which was designed and constructed at the Institute of Agrophysics of PAS and has a matrix of eight MOS (metal oxide semiconductor) sensors. A 20-L volume of maize grain was consolidated in the INSTRON testing machine with pressures of 40 and 80 kPa. The control samples were not compacted, and the maize bed had bulk density. The analyses were carried out at a moisture content of 14% and 17% (w.b.—wet basis). The measurement system facilitated quantitative and qualitative analyses of volatile organic compounds and the intensity of their emission during 30-day storage. The study determined the profile of volatile compounds as a function of storage time and the grain bed consolidation level. The research results indicated the degree of grain degradation induced by the storage time. The highest emission of volatile compounds was recorded on the first four days, which indicated a dynamic nature of maize quality degradation. This was confirmed by the measurements performed with electrochemical sensors. In turn, the intensity of the volatile compound emission decreased in the next stage of the experiments, which showed a decline in the quality degradation dynamics. The sensor responses to the emission intensity decreased significantly at this stage. The electronic nose data on the emission of VOCs (volatile organic compounds) as well as grain moisture and bulk volume can be helpful for the determination of the quality of stored material and its suitability for consumption.

Application of MOX Sensors to Determine the Emission of Volatile Compounds in Corn Groats as a Function of Vertical Pressure in the Silo and Moisture Content of the Bed

“…In Figure 2, the PC1 and PC2 describe the degree of quality degradation of the corn groats progressing over 9 days of storage at 46.75% and 13.27%, respectively. Similar results were reported in studies on rapeseed and corn grains [23,26], but the quality degradation was described only by PC1. The research results presented in Figure 2 are similar to those obtained by Wang et al (2013) [27].…”

“…The compounds were identified using the Wiley library. Compounds with a 75% identity level were selected [23].…”

Non-destructive test to detect adulteration of rice using gas sensors coupled with chemometrics methods

“…In addition, various techniques are used to detect volatile organic compounds (VOC), including: a) non-separative mass spectrometry (Casas-Ferreira et al, 2019;Żytek et al, 2023), b) chromatographic separation (Frigerio et al, 2019), c) micro gas chromatograph (Wang et al, 2019), d) solid-phase microextraction (Kong et al, 2020;Rusinek et al, 2022).…”