No abstract

Effect of the fatty acid composition of monoglycerides and shear on the polymorphic behavior in a water-in-oil (W/O) emulsion semi-solid fats blend was investigated. The bulk fat blend and the W/O emulsion fat blend with added either unsaturated or saturated monoglycerides were prepared using a rapid cooling heat exchanger, and the polymorphic transitions from b 0 to b-form during storage were compared by X-ray diffraction. The peak intensity of the b-polymorph of the samples with added saturated monoglycerides was stronger than that of unsaturated monoglycerides, and the peak intensity of the b-polymorph of the W/O fat blend emulsions was stronger than that of the bulk fat blends. The polymorphic transition to the b-form during storage of the W/O emulsion fat blend was promoted by the applied shear. In contrast, that of the bulk fat blend was retarded by shear. These results suggested that fatty acids, which combined to monoglycerides on the surface of water droplets, influenced the polymorph transformation of the fat crystal network in a continuous semi-solid fat phase because of the acyl-acyl interactions between the fatty acid residues of the monoglycerides and triacylglycerols in the fat crystal network.

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.

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.

Changes in the peroxide value (PV) in instant noodles stored under various conditions were carefully analyzed to examine the oxidation of fat and oils in instant noodles and to evaluate the importance of the maximal 30 mequiv/kg PV standard value in the Food Sanitation Law in Japan from a food safety point of view. The changes in PV in instant noodles stored at 40 to 60C gradually increased and then rapidly increased after exceeding approximately 30 mequiv/kg, regardless of the oxidation temperature. This finding indicates that the PV standard value is meaningful for suppressing the oxidation-induced formation of toxic compounds. The relationships among PV, acid value (AV, amount of free fatty acid) and p-anisidine value (AnV, amount of secondary oxidized products in the oil) in oxidized instant noodles were investigated. There was no significant relationship between PV and AV, and AV and AnV. In contrast, there was a significant relationship between PV and AnV. These results indicate that PV measurements are useful for predicting the formation of toxic compounds, particularly the secondary oxidized products of the oil, and measurements of both PV and AV are very important to accurately determine food deterioration level.3 Corresponding