Formation of the oxidized flavor compounds at different heat treatment and changes in the oxidation stability of milk

Abstract

The oxidized flavor could affect the sensory acceptability of consumers. In this study, the oxidized flavor compound (OFC) in different heated milk was analyzed using the solid phase microextraction–gas chromatography–mass spectrometry (SPME–GC–MS). The concentration of OFC increased with increasing the intensity of heat treatment. The concentrations of heptanal, nonanal, 2‐heptanone, and 2‐nonanone in the heated milk samples were in the range of 1.88–5.51, 1.03–3.26, 6.89–88.04, and 1.46–12.78 μg/kg, respectively. The correlation coefficients between the OFC and the heat intensity were above 0.86. It was found that the intensity of heat treatment (below 80°C for 10 min) could not cause the significant changes in the distribution of fat globules. The contents of partial proteins in milk fat globule membrane gradually destructed with increasing the intensity of heat treatment. The DPPH˙ scavenging activity reduced by 23.15%, and the peroxide value (POV) increased by 37.23% as raw milk was heated at 90°C for 20 min. Values of thiobarbituric acid reactive substances (TBARS) had a tendency to increase as the heated time was operated for 20 min (p < 0.05). It indicated the heat treatment could change the oxidative environment of milk and influence the distribution of milk fat and the formation of oxidized flavor compounds.

Overview on Innovative Packaging Methods Aimed to Increase the Shelf-Life of Cook-Chill Foods

“…Food deriving from a cook-chill supply chain belongs to a special class of products for which a shelf-life enhancement would be desirable to reach as complicated to obtain. Freezing, heating or drying procedure procedures can result in significant changes to the organoleptic properties of foods [65,66]. In addition, the use of chemical additives is not very suitable because they may cause a sensory modification of the product and even if not, their presence could make the product less appealing considering today's most prevalent consumer sensitivity [67].…”

Influence of UV-A radiation on the Selected Nutrient Composition and Volatile Profiling of Whole Milk: Safety and Quality Evaluation

“…Additionally, decreased hexanal content (Table 2) also results in increased oxidative stability. Li et al, (2019b) reported the TBARS level of raw milk in the range 0.02-0.03 whereas TBARS value of milk that was exposed to light and protected from light was 0.92 ± 0.09 mg/kg and 0.59 ± 0.184 mg/kg, respectively (Van et al, 2005). In WM reconstituted (12%) from powder the TBARs value ranged between 0.044 to 0.221 (Li et al, 2019a).…”

Quantification of Free Short-Chain Fatty Acids in Raw Cow Milk by Gas Chromatography-Mass Spectrometry

“…Milk is not only a nutritionally rich food, with essential nutrients such as lactose, protein, fat, vitamins (vitamin A, vitamin E, vitamin C, and B vitamins) and minerals (calcium, iron, zinc, and potassium), but also has active nutrients such as lactoferrin, lactoglobulin and whey protein. Raw milk has a characteristic milky flavor [ 3 , 4 ], which makes it more attractive to consumers. Based on the literature, free fatty acids, especially free short-chain fatty acids (FSCFAs), are critical factors which affect the milk flavor [ 3 , 5 ], and increased FSCFAs are the responsible for the sourness of milk [ 6 ].…”