Character impact odorants of high-heat skim milk powder isolated by simultaneous distillation-extraction.
To identify the character impact odorant of high-heat skim milk powder (HHSMP), a comparative study using ultrahigh-temperature (UHT) milk was performed. Aroma concentrate was prepared by column adsorption combined with simultaneous distillation-extraction. Aroma extract dilution analysis (AEDA) revealed 58 aroma peaks with flavor dilution (FD) factors ranging from 10 to 3000; from these, 41 compounds were identified and 7 compounds were tentatively identified (FD factor > or = 300). Among these HHSMP and UHT milk components, methyl 2-methyl-3-furyl disulfide and bis(2-methyl-3-furyl) disulfide, which appeared to be generated during the processing of each product, were identified. When the results of the AEDA of both samples were compared, it was considered that the characteristic aroma of HHSMP was not explained by a single compound but instead formed from a mixture of several types of compounds contained in common with the UHT milk. The contribution of these compounds to the aroma of HHSMP was confirmed by an aroma simulation experiment.
Model Studies on the Oxidative Stability of Odor-Active Thiols Occurring in Food Flavors
Dilute ethereal solutions of mercaptoacetone (MA), 2-mercapto-3-butanone (MB), 3-mercapto-2-pentanone (MP), 2-methyl-3-furanthiol (MFT), and 2-furfurylthiol (FFT), either alone or in pairs, were stored at 6 °C. During a period of 10 days the oxidation of the thiols to the corresponding disulfides or mixed disulfides was followed by high-resolution gas chromatography/mass spectrometry. In diethyl ether MFT showed the highest oxidation rate, which decreased in the order MFT ≫ MA > MB = MP = FFT. After 1 day, mixed disulfides (e.g. MFT−FFT, FFT−MB) were detectable when pairs of the five thiols dissolved in diethyl ether were stored at 6 °C. MFT oxidized more slowly in dichloromethane than in diethyl ether, and it was stable in pentane. However, a heat treatment increased the oxidation rate of MFT dissolved in dichloromethane or pentane. Keywords: 2-Methyl-3-furanthiol; 2-furfurylthiol; disulfide formation
Determining flavor and flavor variability in commercially produced liquid cheddar whey.
Dried whey and whey protein are important food ingredients. Functionality of whey products has been studied extensively. Flavor inconsistency and flavors which may carry through to the finished product can limit whey ingredient applications in dairy and nondairy foods. The goal of this research was to determine the flavor and flavor variability of commercially produced liquid Cheddar cheese whey. Liquid Cheddar cheese whey from five culture blends from two different stirred-curd Cheddar cheese manufacturing facilities was collected. Whey flavor was characterized using instrumental and sensory methods. Wide variation in whey headspace volatiles was observed between different manufacturing facilities (P < 0.05). Hexanal and diacetyl were two key volatiles that varied widely (P < 0.05). FFA profiles determined by solid-phase microextraction and degree of proteolysis of the whey samples were also different (P < 0.05). Differences in whey flavor profiles were also confirmed by descriptive sensory analysis (P < 0.05). Differences in liquid whey flavor were attributed to differences in milk source, processing and handling and starter culture blend. The flavor of liquid Cheddar cheese whey is variable and impacted by milk source and starter culture rotation. Results from this study will aid future studies that address the impact of liquid whey flavor variability on flavor of dried whey ingredients.