ECODA project number: AIP activity 3
Principal investigators: Jim McCullagh
ECODA’s major soybean industry partner, Sevita International, exports a wide range of soybean varieties to Japan for use by Japanese processors to make soymilk and tofu. Each Japanese customer has a different formulation, process and style of product and, therefore, different soybean varieties work better for some customers than others. To understand the relationship of a soybean variety and the end product, the Guelph Food Technology Centre (GFTC) performed soymilk and tofu sensory evaluations. Japanese processing clients of Sevita International visited the GFTC to consult on sensory evaluation techniques and provide their feedback on varieties being tested.
The GFTC panelists participated in the evaluation of Japanese imported soymilks (two varieties) and GFTC-produced soymilk (five varieties using beans provided by Sevita International). Sensory evaluation results of the Japanese imported soymilks indicated a significant difference in the attributes of (a) raw green, (b) cooked bean, (c) sweet and (d) bitter between the samples, however, no differences in (e) astringency were observed. (The lexicon for these attributes was developed in Activity 1). Based on the colour measurements, a perceptual difference may exist between the two imported Japanese soymilk samples. Sensory evaluation of the GFTC-produced soymilks indicated significant differences among the five varieties for sweetness. OAC Champion was significantly less sweet than Kinusayaka and S03W4. No differences in intensity were observed for the attributes of raw green, cooked bean, bitter and astringent. Based on the colour measurements, a perceptual difference may exist between the soymilk samples with the exception of the OAC Champion/S03W4 and the Kinusayaka/DH530 samples.
The GFTC panelists also participated in the evaluation of six varieties of tofu produced at GFTC using beans provided by Sevita International. Sensory evaluation of the GFTC-produced tofu indicated a significant difference between OAC Champion and DH410SCN for the attribute of beaniness. Based on the colour measurements, a perceptual difference may exist between the tofu samples with the exception of Stargazer-DH420, DH410SCN-S03W4 and DH410SCN-DH420 samples. Although not significant, the different tofu samples exhibited three rough groups of firmness. Samples DH530 and DH420 were consistently the two firmest samples, followed by the mid-range firmness of samples DH410SCN and S03W4. Samples OAC Champion and Stargazer were consistently less firm than any of the other samples that were tested. The responses from the trained panelists were quantified and this data, along with samples of each end product, were sent to the University of Ottawa for analysis in their ultra-high performance liquid chromatography with time-of-flight mass spectrometry (UPLC MS QTOF) analytical facility. Putative identification of specific taste and odour components was achieved by performing discriminant analysis based on human panel data to differentiate variety. A number of biomarkers were identified by discriminate analysis in raw beans and processed tofu or soymilk. Biomarkers that differentiate varieties with significant human panel differences were found. In conclusion, the project has met the objectives of identifying the soy metabolome and employing statistical methods to identify phytochemical biomarkers for variety comparisons and taste preference. The project was able to successfully match preferred commercial varieties with unique Sevita International varieties using metabolomic data. To ensure that the variety recommendations obtained from the University of Ottawa would meet tofu production requirements, Sevita International sent samples of the recommended varieties to a Japanese tofu testing laboratory for analysis.