Compounds Contributing to the Odor of Aqueous Slurries of Soy Protein Concentrate

Abstract

Gas chromatography olfactometry/mass spectrometry (GCO/MS) studies on static and concentrated headspace of the aqueous slurries from soy protein concentrate (SPC) revealed acetaldehyde, methanethiol, hexanal, dimethyl trisulfide (DMTS), and 2-pentyl furan as the most odorous volatiles. Further aroma extract dilution analysis (AEDA) of the volatile extracts identified the following as the odorous substances: hexanal, 2-heptanone, octanal, 2-octanone, 1-octen-3-one, DMTS, 3-octen-2-one, 2-decanone, benzaldehyde, 2-pentyl pyridine and trans, trans-2,4-nonadienal, along with several unidentified odorants. Methanethiol and acetaldehyde, which have low boiling points, were not detected by AEDA, however. This is the first time that acetaldehyde, methanethiol, and dimethyl trisulfide have been identified as primary odorants in SPC.

Changes in aroma characteristics of simulated beef flavour by soy protein isolate assessed by descriptive sensory analysis and gas chromatography

“…Flavour related problems including ''beany'' odour (Boatright & Lei, 1999;Lei & Boatright, 2001;Wolf, 1975) and off-flavour (Inouye, Shiihara, Uno, & Takita, 2002;Maheshwari, Ooi, & Nikolov, 1995;McDaniel & Chan, 1988) have created technical obstacles to be overcome for the increased usage of soy proteins in human foods (Maheshwari et al, 1995). Aside from these undesirable yet hard-to-remove soy aromas, the interactions of soy proteins with desirable aroma components of added flavour formulations have presented a different challenge for soy based products.…”

Factors Influencing the Occurrence of Methanethiol in Aqueous Slurries of Soy Protein Concentrates

“…No further investigations about the occurrence of methanethiol in other soy products or the importance of this highly volatile compound (with a boiling point of 6 °C under atmospheric pressure) to the characteristic odor of soy products were performed. Therefore, our previous results (Boatright and Lei 2000;Lei and Boatright 2001a), for the first time, revealed the importance of methanethiol to the characteristic odor of SPC and SPI.…”

“…During our previous studies on potent volatile compounds responsible for the typical off-flavor associated with soy protein products, we determined that methanethiol was one of the key aroma-impact volatiles for both soy protein concentrate (SPC) and soy protein isolates (SPI) (Boatright and Lei 2000;Lei and Boatright 2001a). The occurrence of methanethiol in soy products was first reported by Qvist and von Sydow (1974) from heated SPI (140 °C for 37 to 41 min); however, it was not found in the unheated samples.…”

“…Also in our previous studies, dimethyl trisulfide (DMTS), another sulfur-containing volatile compound, was identified as one of the major odorants from both SPI and SPC (Boatright and Lei 1999;Boatright and Lei 2000;Lei and Boatright 2001a). Chin and Lindsay (1994) demonstrated that DMTS could be generated from methanethiol in disrupted tissues of cabbage in the presence of transition metals and ascorbate.…”

Flavor profiles of soymilk processed with four different processing technologies and 26 soybean cultivars grown in China

“…The lipoxygenase activities change with the different soybean varieties. [11,12] In fact, the different growing locations, temperature, sun light, and other reasons may lead to the different lipoxygenase activity change in soybean cultivars [13] and significantly affect the contents of odor compounds in soymilk. [14] Similarly, different processing technologies of soymilk have an influence on the odor compounds.…”