科研之友
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摘要
The diffusion of aroma volatiles in set-type acidified dairy matrices of different composition and structure was investigated using the concentration profile technique (CPT) in combination with headspace gas chromatography (HSGC). Multiphase confocal laser scanning microscopy and puncture testing were used to characterize the micro- and macrostructure of the matrices. Aroma volatiles under investigation included diacetyl, (Z)-3-hexenol, ethyl butanoate, ethyl-2-methylbutanoate, (Z)-3-hexenyl acetate, ethyl hexanoate and limonene, and covered a wide range of hydrophobicity. CPT in combination with HSGC was found suitable to determine apparent diffusion coefficients at equilibrium. Increased overall protein content decreased the diffusivity of hydrophobic volatiles. At 4% protein content, diffusivity remained unaffected by process-induced changes in the protein network density. Addition of milk fat substantially decreased the mobility of hydrophobic volatiles. In milk fat-containing matrices, the addition of pectin did not change the diffusion properties of the volatiles, independent of their hydrophobicity. %26lt;br%26gt;Practical ApplicationsThis study is relevant to the producers of acidified dairy products such as yoghurt, fresh cheese and quarg. The results specify within which boundaries several core parameters of manufacture, such as the addition of pectin, the intensity of milk heating, shearing and adaptations in protein and fat content, may be changed at a minimized risk of altered aroma delivery during consumption. This information amplifies the technological possibilities of the manufacturers and increases their flexibility in terms of product composition and processing. Aroma suppliers could use the outcomes of this study to modify the composition of their aromas based on dairy product specifications and the hydrophobicity of the individual aroma compounds they are using.
- 出版日期2013-12
