Volatile Compounds of Dry Bean Seed {phaseolus Vulgaris L.)

Volatile compounds of uncooked dry bean {Phaseolus vulgaris L.) cultivars representing 3 market classes (black, dark red kidney and pinto) grown in 2005 were isolated with headspace solid phase microextraction (HS-SPME), and analyzed with gas chromatography mass spectrometry (GCMS). A total of 62 volatiles consisting of aromatic hydrocarbons, aldehydes, alkanes, alcohols and ketones represented on average 62, 38, 21, 12, and 9 x 10^ total area counts, respectively. Bean cultivars differed in abundance and profile of volatiles. The combination of 18 compounds comprising a common profile explained 79% of the variance among cultivars based on principal component analysis (PCA). The SPME technique proved to be a rapid and effective method for routine evaluation of dry bean volatile profile. INTRODUCTION The low Canadian per capita dry bean consumption at 2.5 kg per annum in 2005 [1], may be due to the unsophisticated taste and flavor consumers generally associate with dry bean products despite their nutritional and health benefits. Flavor, an important factor in overall acceptability, and cooking time were two main characteristics used by consumers to select a given type of bean according to a survey conducted in Mexico [2, 3]. Flavor is most often ascertained on cooked or canned bean. Presently, flavor of canned bean is judged subjectively for flat, dull, bittemess, acid, sweet and offflavor by a trained and experienced sensory evaluation team with scores ranging between 2.4 to 3.2 (2=fair, 3=good and 4=very good). Studies of flavor in dry bean [4, 5, 6] were preceded by identification of about 90 volatile components of canned whole bean [7]. SPME is a simple, sensitive, robust, rehable, low cost and very popular fast screening sampling technique based on analyte diffusion that combines the advantages of both static and dynamic head space for qualitative volatile analysis [8]. Information currently available on the volatile components of dry beans is deficient and fiiU investigations of the uncooked beans are long overdue. In the present study, HS-SPME was applied as a solvent-free sample preparation method, with GC-MS analysis, to provide the initial investigation of the volatile profile of dry bean from Manitoba. This is the first step in unraveling and elucidating bean volatiles as a prerequisite in developing new cultivars for increased economic value and novel bean ingredients for health and fiinctional food