Odor detection thresholds of hexanal, 2-heptenal, 2-pentanone, and 2,4-nonadienal were determined in spring water, high temperature short time (HTST) 2% fat milk, and extended shelf life soymilk. The efficacy of odor scavenger's beta-cyclodextrin, D-sorbitol, and nylon 6 in removing these odors was also determined. The odor thresholds of the different odor and media combinations were as follows: hexanal in spring water, milk, and soymilk were 585, 339, and 536 ppb respectively; 2-heptenal in spring water, milk, and soymilk were 2,092, 2,322, and 3,184 ppb respectively; 2-pentanone in spring water, milk and soymilk were 24,925, 29,255 and 33,271 ppb respectively; and 2,4-nonadienal in spring water, milk, and soymilk were 164, 326, and 243 ppb respectively. These amounts reference the initial spiked concentration that was added directly to the media. Both hexanal and 2,4-nonadienal had lower thresholds than 2-heptenal and 2-pentanone in all of the media. The odor detection thresholds of 2-heptenal, 2-pentanone, and 2,4-nonadienal did show a significant difference between soymilk and water, but not for milk. The efficacy of the odor scavengers were determined by use of solid phase micro-extraction gas chromatography (SPME-GC) and sensory evaluation. Hexanal, 2-heptenal, 2-pentanone, and 2,4-nonadienal were spiked at 1,000, 3,000, 30,000, and 300 ppb respectively in all three media. Beta-cyclodextrin, D-sorbitol, and nylon 6 were added at a level of 0.1% w/v and 1.0% w/v. In all of the media, beta-cyclodextrin was found to significantly reduce hexanal, 2-pentanone, 2-heptenal, and 2,4-nonadienal at both 0.1% w/v and 1.0% w/v. Nylon 6 was not found beneficial. / Master of Science

Master of Science / Department of Agricultural Economics / Xianghong Li / Hikaru H. Peterson / The organic food market in the United States expanded rapidly at annual rates between 12% and 21% from 1997 to 2008, yet the adoption rate of organic farming remained stagnant. Industry sources suggest that the degree of outsourcing organic inputs has been increasing during the most recent years. Organic foods are available at traditional supermarkets and mass merchandisers. Many retailers now offer organic food products in their private labels. This study focuses on organic soymilk, which illustrates these recent trends. China, a major low income country which supplies organic agricultural ingredients to the U.S. , has raised food safety concerns fueled by recent incidents. Organic foods have been marketed in China as eco-products in an effort to promote safer foods to meet domestic needs. While organic soybean is one of China’s primary organic exports, China has been the leading importer of conventional soybeans with U.S. as its largest source, but most U.S. production is transgenic. China has a labeling policy on GM (genetically modified) products, which has been more tightly enforced in recent years. This thesis examines U.S. and Chinese consumers’ valuations of attributes of processed organic products, with an emphasis on eliciting their preferences of organic ingredients from different origins, in the case of soymilk. A survey was designed for each country. The U.S. survey was administered online nationwide. An enumerated survey was administered at three types of food retail channels in Beijing, Shanghai and Guangzhou in China. Respectively, 316 and 300 responses were collected from the U.S. and China. Choice experiment was used to elicit consumer values for various attributes of soymilk in both markets. The results show that consumers in both countries are willing to pay premiums for processed foods such as soymilk with organic and non-GMO ingredients. The premium for organic soybeans is significantly higher than that for non-GMO beans. The results also indicate that U.S. consumers hold strong preferences for organic soymilk produced with domestically produced soybeans. In terms of brand preferences, U.S. respondents are willing to pay more for national brands relative to store brands, with taste as a major differentiating factor. In contrast, Chinese consumers’ valuations depend greatly on nationalities of certifying agencies. U.S. certified organic product was perceived higher than EU or Chinese certified organic products, but Chinese-certified non-GMO products were preferred over those certified by U.S. agencies. Chinese consumers’ values varied by cities and retail types where respondents were surveyed.