The aim of the current study was to identify quality indicators of fat (14.50 ± 0.75%) and low-fat (4.79 ± 0.63%) raw ground beef by monitoring changes in physicochemical and microbiological parameters during aerobic refrigerated storage, such as water-holding capacity, pH, thiols, carbonyl compounds, thiobarbituric acid reactive substances (TBARS), metmyoglobin, deoxymyoglobin, oxymyoglobin color indices, pseudomonads, Brochothrix thermosphacta, and total viable counts. Meat packaged in air-permeable polyethylene plastic film was stored under controlled isothermal conditions (0, 5, 10, and 15 °C). A population level of pseudomonads equal to 7.0 ± 0.5 log10 colony forming units (CFU)/g was considered as the potential spoilage level. Using principal component analysis, samples were distinguished on the basis of their microbial load. A significant positive correlation between microbial population and carbonyls, metmyoglobin, TBARS, water-holding capacity, and a negative correlation with thiols and color parameters (L* , chroma) were observed. Two different approaches were followed to estimate the quality status of samples: (i) the partial least square (PLS) regression with R2 of 0.93 and root mean square error prediction of 0.44 for pseudomonads, using the above physicochemical characteristics as the dominant input variables, which allowed prediction of the microbiological status of ground beef regardless of time-temperature storage profile and fat content, and (ii) a square-root-type model (adjusted R2 of 0.952) that satisfactorily predicted the growth of spoilage pseudomonads under isothermal and dynamic conditions, regardless of the above physicochemical changes. The above results suggest that depending on the available input data, the two modeling approaches can accurately (and complementarily) assess quality of aerobically stored ground beef. PRACTICAL APPLICATION: Changes in appearance and quality of fat and low-fat raw ground beef are associated with physicochemical alteration and/or microbial growth. The study provides two different modeling approaches that can be integrated in an intelligent interface of the refrigerator having specific colorimetric and/or temperature sensors, to evaluate in a convenience way the quality of stored meat thus reducing domestic waste: the partial least square model was based on physicochemical parameters (particularly chroma, metmyoglobin, and thiobarbituric acid reactive substances), while the square root model was based on the time-temperature conditions during storage.

中文翻译：

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用于预测冷藏有氧储存期间脂肪和低脂肪生碎牛肉质量的微生物和理化参数

本研究的目的是通过监测有氧冷藏过程中物理化学和微生物参数的变化，如持水量，确定脂肪 (14.50 ± 0.75%) 和低脂 (4.79 ± 0.63%) 生碎牛肉的质量指标。容量、pH、硫醇、羰基化合物、硫代巴比妥酸反应性物质 (TBARS)、高铁肌红蛋白、脱氧肌红蛋白、氧合肌红蛋白颜色指数、假单胞菌、热链丝菌和总活菌数。包装在透气聚乙烯塑料薄膜中的肉类在受控等温条件下（0、5、10 和 15 °C）储存。假单胞菌种群水平等于 7.0 ± 0.5 log10 菌落形成单位 (CFU)/g 被认为是潜在的腐败水平。使用主成分分析，根据微生物负荷区分样品。观察到微生物种群与羰基、高铁肌红蛋白、TBARS、持水能力之间显着正相关，而与硫醇和颜色参数（L*、色度）呈负相关。采用两种不同的方法来估计样品的质量状态：(i) 偏最小二乘 (PLS) 回归，R2 为 0.93，均方根误差预测为 0.44，使用上述物理化学特征作为主要输入变量，它允许预测碎牛肉的微生物状态，而不管时间-温度存储曲线和脂肪含量，以及 (ii) 平方根型模型（调整后的 R2 为 0.952），令人满意地预测了等温和动态下腐败假单胞菌的生长条件，不考虑上述物理化学变化。上述结果表明，根据可用的输入数据，这两种建模方法可以准确地（并且互补地）评估有氧储存的碎牛肉的质量。实际应用：脂肪和低脂肪生碎牛肉的外观和质量变化与理化改变和/或微生物生长有关。该研究提供了两种不同的建模方法，可以将它们集成到具有特定色度和/或温度传感器的冰箱的智能界面中，以方便的方式评估存储肉类的质量，从而减少生活垃圾：偏最小二乘模型基于关于理化参数（特别是色度、高铁肌红蛋白和硫代巴比妥酸反应物质），