Abstract This study aims to compare the quality of fat extracted from different priced dry pet food for adult cats through classical and instrumental methods: pressure differential scanning calorimetry (PDSC), Fourier transform infrared spectroscopy (FT-IR) or gas chromatography (GC). Fat extracted from pet food was examined for induction time (IT), fatty acid composition, free fatty acid (FFA) content and peroxide value with the use of PDSC, GC, acid–base and iodometric titration, respectively. FT-IR data from the selected spectral regions correlate with the value of oxidation IT or the content of FFA. This resulted in construction of a reference model for IT with the following statistical features: R calibration = 0.917 (RMSEC = 28.0) and R validation = 0.841 (RMSEP = 34.6). For fatty acid content, model statistics were as follows: R calibration = 0.912 (RMSEC = 0.61) and R validation = 0.856 (RMSEP = 0.75). Discriminant model that uses spectral data alone, calculated with performance index 83.7 allowed distinguishing the studied pet food samples due to the price. Studies conducted proved PDSC and IR as reliable analytical techniques to control and monitor the quality of dry pet food for cats. Considering quality of the studied samples, it was proved that low-priced pet foods can be stored longer than premium-priced ones, while former is nutritionally more beneficial for adult cats.

中文翻译：

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联合使用 GC、PDSC 和 FT-IR 技术来表征从成年猫商业全干宠物食品中提取的脂肪

摘要 本研究旨在通过经典和仪器方法：压力差示扫描量热法 (PDSC)、傅里叶变换红外光谱 (FT-IR) 或气相色谱法 (GC)，比较从不同价格的成年猫干宠物食品中提取的脂肪质量。分别使用 PDSC、GC、酸碱和碘滴定法检测从宠物食品中提取的脂肪的诱导时间 (IT)、脂肪酸组成、游离脂肪酸 (FFA) 含量和过氧化值。来自选定光谱区域的 FT-IR 数据与氧化 IT 值或 FFA 含量相关。这导致构建了具有以下统计特征的 IT 参考模型：R 校准 = 0.917 (RMSEC = 28.0) 和 R 验证 = 0.841 (RMSEP = 34.6)。对于脂肪酸含量，模型统计如下：R 校准 = 0.912 (RMSEC = 0.61) 和 R 验证 = 0.856 (RMSEP = 0.75)。单独使用光谱数据的判别模型，使用性能指数 83.7 计算，允许根据价格区分研究的宠物食品样品。进行的研究证明 PDSC 和 IR 是控制和监测猫干宠物食品质量的可靠分析技术。考虑到研究样本的质量，证明低价宠物食品比高价宠物食品可以储存更长时间，而前者在营养上对成年猫更有益。进行的研究证明 PDSC 和 IR 是控制和监测猫干宠物食品质量的可靠分析技术。考虑到研究样本的质量，证明低价宠物食品比高价宠物食品可以储存更长时间，而前者在营养上对成年猫更有益。进行的研究证明 PDSC 和 IR 是控制和监测猫干宠物食品质量的可靠分析技术。考虑到研究样本的质量，证明低价宠物食品比高价宠物食品可以储存更长时间，而前者在营养上对成年猫更有益。