The aim of the present study was to investigate the potential use of Fourier transform infrared (FTIR) spectroscopy to quantify biochemical changes occurring in ham slices packed with probiotic supplemented edible films and treated with High Pressure Processing (HPP), in monitoring spoilage. Details regarding the data collection and experimental procedure were presented by Pavli et al. (2017). A series of Partial Least Squares (PLS) models were developed to correlate spectral data from FTIR analysis with ham spoilage during storage under vacuum at different storage temperatures (4, 8 and 12 °C). FTIR spectra were collected from the surface of the ham samples in parallel with microbiological analysis of total viable counts (TVC) and lactic acid bacteria (LAB). Qualitative interpretation of spectral data was based on a sensory evaluation, using a hedonic scale, classifying the samples in three quality classes, fresh, semi-fresh and spoiled. The scope of the modeling approach was to discriminate the ham slices in their respective quality class and additionally to predict the microbial population directly from spectral data. The results obtained demonstrated that the processing of the samples affected the performance of classification in the sensory classes, with better results observed in the case of control samples without HPP and for ham slices packed with probiotic supplemented (PS) edible films. The performance of PLS regression models on providing quantitative estimations of microbial counts were based on specific figures of merit (bias factor, accuracy factor, root mean square error, percentage of prediction error). Bias and accuracy factors were close to unity for both microbial groups tested for samples without HPP, whereas for HPP treated samples the values of these indices ranged from 0.963 to 1.332, depending on the case and indice. The results of this study demonstrated for the first time that although FTIR can be used reliably for the rapid assessment of sliced ham, additional processes such as HPP can affect its performance.

本研究的目的是研究傅立叶变换红外（FTIR）光谱技术在定量监测掺有益生菌的可食用薄膜包装并经高压加工（HPP）处理的火腿切片中发生的生化变化的潜力。有关数据收集和实验程序的详细信息由Pavli等人提供。（2017）。开发了一系列偏最小二乘（PLS）模型，以将来自FTIR分析的光谱数据与不同存储温度（4、8和12°C）的真空存储期间的火腿腐败相关联。从火腿样品表面收集FTIR光谱，同时进行总活菌数（TVC）和乳酸菌（LAB）的微生物学分析。光谱数据的定性解释基于感官评估，使用享乐秤，将样品分为三个质量等级，新鲜，半新鲜和变质。建模方法的范围是区分火腿片的质量等级，并直接从光谱数据中预测微生物的数量。获得的结果表明，样品的处理影响了感官类别的分类性能，在没有HPP的对照样品以及装有益生菌补充（PS）食用薄膜的火腿切片的情况下，观察到了更好的结果。PLS回归模型在提供微生物数量定量估计上的性能基于特定的优值（偏倚因子，准确性因子，均方根误差，预测误差百分比）。对于不使用HPP的样品进行测试的两个微生物组，其偏差和准确度因子均接近于1，而对于使用HPP处理的样品，根据情况和指标，这些指数的范围从0.963到1.332。这项研究的结果首次证明，尽管FTIR可以可靠地用于切片火腿的快速评估，但是诸如HPP之类的其他过程可能会影响其性能。