Application of FT‐NIR spectroscopy in assessment of used frying fats and oils*
Application of FT‐NIR spectroscopy in assessment of used frying fats and oils*
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DOI：
10.1002/ejlt.201300270
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发表时间：
2014-06
影响因子：
2.7
通讯作者：
C. Gertz;D. Behmer
中科院分区：
文献类型：
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作者：
C. Gertz;D. Behmer
利用近红外光谱（NIRS）技术建立了一种快速、经济的评价煎炸油品质的方法。使用标准DGF方法分析了快餐店、餐馆、渔业、面包店和其他油炸行业中使用的大量新鲜、使用过和丢弃的油的热氧化脂肪降解的相关参数，例如总极性化合物（TPC）、二和聚合三酰基甘油（DPTG）、茴香胺值（AnV）和酸值（AV）。此外，脂肪酸组成，包括反式脂肪酸，碘值（IV）和单体氧化三酰基甘油（MonoxTG）的含量测定来描述油炸食品的营养价值。MonoxTG是不同分子量的氧化甘油三酯的混合物，形成在GPC中分离的两个基团。建议称它们为总氧化产物（TOP），因为与AnV相比，这两组单体氧化TAG客观且可靠地表征了用过的煎炸油中的整个氧化产物谱。这组氧化单体三酰基甘油（TOP）在煎炸油中的典型浓度为3至15%。所有NIRS测定均获得了较高的校准准确度。所有方法均使用测试集验证进行验证。采用偏最小二乘回归（PLS）将光谱数据与TPC、TOP、DPTG、AV和AnV相关联。采用近红外光谱法对煎炸油进行分析，获得了较高的校正精度。对于TPC，在2.0 - 50.3%范围内，决定系数R2为97.6，RMSEP为1.56%。此外，成功预测DPTG，R2 = 99.4，RMSEP = 0.47%（0-31.3%）。在0.1至173的宽范围内测量AnV，R2 = 95.7，RMSEP = 6.8。对于表示为AV的酸度，涵盖0至5.7的宽范围，R2值为97.4%，RMSEP为0.17%。一个新的参数，以监测氧化程度（TOP）已示出的R2 = 96.8和RMSEP = 0.57%实际应用：近红外光谱是一个有用的工具，用于监测油炸过程中使用的油炸脂肪和油的热氧化变化。这有助于优化油炸过程并提高待油炸食物的质量。从本研究中获得的结果可以推断，TPC的测定是不充分的。所有氧化单体甘油三酯TOP的测定提供了更好的信息，这些化合物被讨论对人体健康有不利影响。
NIR spectroscopy (NIRS) was used to develop a fast and cost-effective method to assess the quality of deep-frying oil. A large number of fresh, used and discarded oils, used in fast food units, restaurants, fisheries, bakeries, and other frying industries, were analyzed for relevant parameters of thermo-oxidative fat degradation such as total polar compounds (TPC), di- and polymerized tri-acylglycerols (DPTG), anisidine value (AnV) and acid value (AV) using the standard DGF methods. Additionally, the fatty acid composition, including trans fatty acids, iodine value (IV) and the contents of monomeric oxidized tri-acylglycerols (MonoxTG) were determined to describe the nutritional value of fried food. MonoxTG is a mixture of oxidized triglycerides of different molecular weight forming two groups separated in GPC. It is suggested to call them total oxidized products (TOP) as both groups of monomeric oxidized TAGs characterize, objectively and reliably, the whole spectrum of oxidized products in a used frying oil in contrast to AnV. Typical concentrations of this group of oxidized monomeric tri-acylglycerols (TOP) in frying oils are 3 up to 15%. High calibration accuracy was obtained for all NIRS determinations. All methods were validated using test set validations. Partial least squares regression (PLS) was used to correlate spectral data with TPC, TOP, DPTG, AV, and AnV. High calibration accuracy was obtained for the NIR determination of all parameters analyzing used frying oils. For the TPC, the coefficient of determination R2 was 97.6 with an RMSEP of 1.56% over a range from 2.0 to 50.3%. Also DPTG was predicted successfully with R2 = 99.4 and RMSEP = 0.47% (0–31.3%). The AnV was measured over a broad range of 0.1 to 173 with R2 = 95.7 and RMSEP = 6.8. For acidity expressed as AV covering a wide range from 0 to 5.7 the R2 value was 97.4% with an RMSEP of 0.17%. A new parameter to monitor the degree of oxidation (TOP) has shown an R2 = 96.8 and RMSEP = 0.57% Practical applications: NIRS is a useful tool for monitoring the thermo-oxidative changes in used frying fats and oils during the frying process. This helps to optimize the frying process and to improve the quality of the food to be fried. From the results obtained in this study, it can be deduced that the determination of the TPC is not sufficient. The determination of all oxidized monomeric triglycerides TOP provide better information of those compounds which are discussed to have a detrimental effect to human health.