Antioxidant activity toward fish oil triacylglycerols exerted by sphingoid bases isolated from butter serum with α-tocopherol.

A mixture of sphingoid bases (SPGs) was prepared from butter serum, a by-product of anhydrous milk fat production. The mixture comprised seven types of SPGs with C16 to C19 alkyl chains. These milk SPGs inhibited the oxidation of fish oil triacylglycerol (TAG) more effectively than did a standard SPG (d18:1) with α-tocopherol. Reaction products were prepared from the combination of d18:0 or d18:1 with acrolein and propanal. Both sets of reaction products showed antioxidant activity toward fish oil TAG. Antioxidant activity of reaction products from d18:0 was stronger than that of reaction products from d18:1, suggesting that the molecule d18:0 may be a significant focus of the difference in antioxidant activity between milk SPGs and d18:1. To use SPGs as food additives in the future, an appropriate source of SPGs will be needed, and butter serum appears to have promise as a source of functional SPGs with strong antioxidant activity.

Metabolomics analyses of the combined effects of lactic acid bacteria and Penicillium camemberti on the generation of volatile compounds in model mold-surface-ripened cheeses.

The flavor of white mold cheese is attributed to the formation of aroma compounds associated with complex effects of bacteria and fungi, resulting in difficulties in flavor design for new cheeses. This study aimed to identify the microbial basis of flavor by identifying the combined effects of LD type lactic acid bacteria (LAB) starters and Penicillium camemberti on the generation of metabolites during the ripening process. Metabolomics analyses were performed on three model cheeses: normal cheese, no-mold cheese with only LAB, and no-LAB cheese with only white mold. Aroma compounds and their potential precursors were analyzed using headspace solid-phase microextraction-gas chromatography/mass spectrometry (GC/MS) and solvent extraction-GC/MS, respectively. Measurements during ripening and multivariate analyses on the data revealed the relationship between the microorganisms and metabolic activities, which were classified into four groups: metabolites generated by LAB and degraded by P. camemberti; metabolites generated by P. camemberti and degraded or inhibited by LAB; metabolites generated by P. camemberti and enhanced by LAB; and metabolites exhibiting no interaction between P. camemberti and LAB. The characteristic compounds in LAB and white mold cheeses were mainly products of sugar and protein metabolism, respectively. The involvement of fatty acids, methyl ketones, and secondary alcohol metabolic pathways in the late-ripening stage was confirmed, and the profiles of volatile metabolites contributing to the characteristic aroma of the white mold cheese in the fermentation process were also confirmed.

Effects of Flavor and Texture on the Sensory Perception of Gouda-Type Cheese Varieties during Ripening Using Multivariate Analysis.

The impact of flavor composition, texture, and other factors on desirability of different commercial sources of Gouda-type cheese using multivariate analyses on the basis of sensory and instrumental analyses were investigated. Volatile aroma compounds were measured using headspace solid-phase microextraction gas chromatography/mass spectrometry (GC/MS) and steam distillation extraction (SDE)-GC/MS, and fatty acid composition, low-molecular-weight compounds, including amino acids, and organic acids, as well pH, texture, and color were measured to determine their relationship with sensory perception. Orthogonal partial least squares-discriminant analysis (OPLS-DA) was performed to discriminate between 2 different ripening periods in 7 sample sets, revealing that ethanol, ethyl acetate, hexanoic acid, and octanoic acid increased with increasing sensory attribute scores for sweetness, fruity, and sulfurous. A partial least squares (PLS) regression model was constructed to predict the desirability of cheese using these parameters. We showed that texture and buttery flavors are important factors affecting the desirability of Gouda-type cheeses for Japanese consumers using these multivariate analyses.

Model studies on volatile release from different semisolid fat blends correlated with changes in sensory perception.

The effect of dispersed aqueous droplets in water-in-oil (W/O)-emulsion semisolid fats on aroma release and sensory perception was investigated on margarine models where model aroma substances were added. Aroma release from W/O-emulsion fat blends and bulk fat blends with added monoglycerides combining different fatty acids of various short-chain free fatty acids, methylketones, esters, and lactones were measured using headspace solid phase microextraction-gas chromatography/mass spectrometry (SPME-GC/MS), and their perception profiles were evaluated by sensory analysis. The presence of aqueous phase in a fat blend significantly reduced the headspace concentrations of butanoic acid and hexanoic acid, and also decreased the perceived intensity of total aroma and cheesy aroma. The aroma release of methylketones, esters, and lactones from the W/O-emulsion fat blends increased with increasing carbon chain length of the volatile molecules. The intensity of aroma perception in a W/O-emulsion fat blend depended on the melting point of the fatty acids (oleic, palmitic, stearic, and behenic) of the monoglyceride used as an emulsifier. Thus, aroma release from a W/O-emulsion semisolid fat blend was influenced by interactions between aroma volatiles and the dispersed aqueous droplets and by their viscoelastic properties.