Background Deodorizer distillate (DD oil) is an important by-product obtained during the refining and deodorization process of vegetable oil (The processing procedure of vegetable oil is shown in Fig.1). Its main components not only include free fatty acids and glycerides, but also are rich in phytosterols, tocopherols (vitamin E), squalene and other high-value ingredients. However, risk factors such as polycyclic aromatic hydrocarbons (PAHs) and pesticides that may be contained in DD oil can pose a potential threat to the safety of the food chain and human health.
Analysis/Progress In this paper, the types and sources of risk factors in DD oil were systematically reviewed, with a focus on PAHs and pesticides. To date, over 400 types of PAHs have been identified, and the International Agency for Research on Cancer (IARC) has established a comprehensive carcinogenicity assessment and classification system for 16 PAHs detected in food matrices, as summarized in Tab. 1. Market oil sample testing revealed detection rates of 17%, 21%, and 42% for pyrethroids, organochlorine, and organophosphorus pesticides, respectively. Subsequently, the research advancements and applications of modern detection technologies were discussed, including gas chromatography/liquid chromatography-mass spectrometry (GC/LC-MS), QuEChERS sample preprocessing technique, and emerging biomimetic enzyme electrochemical sensors (Fig. 2). GC/LC-MS not only enables efficient separation of risk factors but also provides molecular structural information through mass spectrometry, significantly enhancing the sensitivity and selectivity of risk factor analysis. The QuEChERS sample pretreatment technique is particularly suitable for the rapid extraction and efficient purification of multiple contaminants in complex matrices like DD oil. Its combination with GC/LC-MS can markedly improve the efficiency of risk factor analysis. Emerging detection technologies, such as biomimetic enzyme electrochemical sensing, are gaining attention as research hotspots in contaminant detection and are expected to achieve rapid and stable analysis due to their advantages of high selectivity, ease preparation and low cost. Finally, the relevant research progress of risk factor removal technologies (Fig. 3) was reviewed. The advantages and disadvantages of the existing methods, such as distillation, membrane separation technology, adsorption and purification, and microbial degradation, were summarized and compared in terms of three indicators, namely, removal efficiency, process cost, and environmental friendliness. Distillation, due to its advantages of large processing capacity and relatively low energy consumption, is more suitable for the large-scale industrial removal of primary pollutants. However, it may damage heat-sensitive active components. Membrane separation technology can purify and concentrate natural extracts under room temperature conditions, effectively avoiding the negative effects of traditional high-temperature processes on active ingredients. However, it exhibits limitations including high energy demand and susceptibility to membrane fouling, consequently elevating operation and maintenance costs. Adsorption method can efficiently remove pollutants with low energy consumption, but the limited capacity of adsorbent materials and potential secondary pollution remain challenges. Microbial degradation method causes minimal damage to soil and water bodies and consumes little energy, but it has strict requirements for environmental conditions.
Conclusion/Prospect In the field of oil processing, the risk management and resource utilization of DD oil require a systematic solution integrating fundamental research and technological innovation. For the detection and analysis of risk factors, future efforts could combine nanomaterial enrichment and in-situ ionization mass spectrometry to develop rapid and non-destructive real-time detection systems, thereby advancing the standardization process. Regarding the identified risk factors, individual removal method has inherent limitations. Future work should explore the strategic integration of multiple technologies and investigate novel high-efficient and energy-saving approaches such as directed enzymatic hydrolysis and low-temperature plasma degradation. Ultimately, it is necessary to optimize the deodorization process, establish an integrated system of "detection-removal-monitoring", and improve relevant standards and regulations to ensure the safety of edible oils.
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