Binding characteristics of cyclodextrins in model systems and their effectiveness on entrapping beany flavor compounds in soymilk

This study focused on investigating the effectiveness of fat replacers and cyclodextrins on binding and/or entrapping various volatile compounds that are responsible for characteristic odors and flavors in food systems. The volatile compounds in model food systems were determined utilizing gas chromatography and identified by gas chromatography-mass spectrometry. A new solid phase microextraction (SPME) technique was developed using a polydimethylsiloxane fiber to extract effectively the volatile compounds from soymilk.; Results showed that fat replacers were not generally effective for binding the volatile compounds, whereas cyclodextrins were effective for entrapping these compounds. α-Cyclodextrin was the most effective for lowering headspace concentrations of volatile compounds in model systems, particularly for alkyl aldehydes. As concentrations of the cyclodextrins increased, volatile concentrations in the headspace decreased significantly. A combination of α-, β- and γ-cyclodextrins was as effective as soybean oil.; The SPME fiber method was effective for extracting the volatile compounds in soymilk that are associated with beany flavor. The SPME was capable of extracting volatile compounds present at parts per billion levels. The compounds identified from commercial soymilk included 11 aldehydes, 2 ketones, 2 alcohols, and 1 furan derivative.; At higher levels of cyclodextrins in model systems, the headspace concentrations of volatile compounds rapidly reached their equilibration. Most volatile compounds were entrapped by 80% or more at a 3% level of α-cyclodextrin. The entrapment was more effective for the compounds having longer chains. A response surface model of each volatile compound showed moderate decreases in GC peak areas with an increase of the concentration of α-cyclodextrin and a decrease of concentrations of volatile compounds. The molar ratio of the volatile compound to α-cyclodextrin was more than 1:1500 for 50% entrapment. α-Cyclodextrin-volatile complexes were stable during 16 days at 4°C.; Human salivary α-amylase was slow in hydrolyzing α-cyclodextrin at 37°C, whereas they were relatively fast for γ-cyclodextrin. The hydrolysis of γ-cyclodextrin increased significantly the headspace concentrations of an added standard compound, 1-octen-3-ol, suggesting that the compound was released when its cyclic structure was broken by the hydrolysis.