Swiss Cheese Flavor Variability Based on Correlations of Volatile Flavor Compounds, Descriptive Sensory Attributes, and Consumer Preference.

Minimizing flavor variation in cheeses without perceived flavor defects in order to produce a consistent product is a challenge in the Swiss cheese industry. This study evaluated flavor variability based on correlations of volatile flavor compounds and sensory attributes. The headspace concentrations of volatile compounds were analyzed using selected ion flow tube-mass spectrometry (SIFT-MS), while the sensory attributes were evaluated using descriptive sensory analysis and consumer testing. The important discriminating volatile compounds were classified into five functional groups: sulfur-containing compounds (methyl mercaptan, hydrogen sulfide, dimethyl disulfide, dimethyl trisulfide, and methional), organic acids (propanoic acid, acetic acid, 3-methylbutanoic acid), aldehydes (3-methylbutanal, butanal, and 2-methylpropanal), a ketone (2,3-butanedione), and an ester (ethyl hexanoate). Correlations were identified among volatile compounds and between volatile compounds and sensory attributes. Only a small number of volatile compounds strongly correlated positively or negatively to a specific sensory attribute. Nutty malty, milkfat lactone, salty, umami, and sweet positively correlated to overall liking and nutty flavor liking of Swiss cheese. Evaluation of cheese flavor using correlations between volatile compounds and sensory attributes provided further understanding of the complexity of flavor and flavor variability among Swiss cheeses manufactured from different factories that can be used to improve flavor consistency of Swiss cheeses.

The Effect of pH and Temperature on Cabbage Volatiles During Storage.

During storage of shredded cabbage, characteristic sulfurous volatile compounds are formed affecting cabbage aroma both negatively and positively. Selected ion flow tube-mass spectrometry (SIFT-MS) was used to measure the concentration of cabbage volatiles during storage. The volatile levels of cabbage samples were measured at pH 3.3 to 7.4 at 4 °C for 14 d, and pH 3.3 at 25 °C for 5 d in order to determine the effect of pH and temperature. Aroma intensity, best aroma, freshness, and off odor were evaluated in a sensory test of the samples at 4 °C. The desirable volatile allyl isothiocyanate was lower in high pH samples (pH 7.4 and 6.4), whereas higher concentrations were detected in low pH samples (pH 3.3 and 4.6). Lipoxygenase volatiles, which produce a fresh green and leafy aroma in cabbage, were generated in very low amounts at any pH value. High pH samples generated significantly higher concentrations of off odors such as dimethyl sulfide, dimethyl disulfide, dimethyl trisulfide, and methanethiol. Sensory tests showed that higher pH samples had significantly stronger off odor and lower desirable cabbage aroma than lower pH samples. Thus, sensory results matched the volatile results in that samples at higher pH levels formed the highest amount of undesirable volatiles and the least amount of desirable volatiles. Storage at 25 °C produced similar concentrations of allyl isothiocyanate, but significantly higher levels of off odors, than at 4 °C. Shredded cabbage products should be stored in low pH dressings to minimize formation of off odors and maximize formation of characteristic, desirable cabbage odor.

Volatile profile of cashews (Anacardium occidentale L.) from different geographical origins during roasting.

UNLABELLED: Volatile compounds were quantified in the headspace of Indian, Vietnamese, and Brazilian cashews, both raw and during roasting by selected ion flow tube-mass spectrometry. The optimum roasting times based on color measurements were also determined. Raw cashews were oil roasted for 3 to 9 min at 143 °C and color and volatiles measured. An excellent correlation, following a pseudo 1st-order reaction, was found between L* value and roasting time; darkness increases as roasting time increases. The optimum roasting time was 6, 8, and 9 min for Vietnamese, Indian, and Brazilian cashews, respectively. Raw cashews had lower concentrations of volatiles than roasted cashews. Most volatiles significantly increased in concentration during roasting of Brazilian, Indian, and Vietnamese cashews. Only a few volatiles significantly decreased during roasting. Ethanol and 1-heptene significantly decreased during roasting in Brazilian cashews and toluene decreased in Vietnamese cashews. Brazilian cashews had significantly higher levels of most volatiles than Indian and Vietnamese cashews. Most volatile levels in Indian and Vietnamese cashews were not significantly different. Of the volatiles, Strecker aldehydes, including methylbutanal, 2-methylpropanal, and acetaldehyde, were at the highest concentration in roasted cashews. The Maillard reaction contributed to the formation of most of the volatiles in cashews from the 3 countries. There was also degradation of sugars to form furan-type compounds and oxidation of lipids to form alkanals such as hexanal. PRACTICAL APPLICATION: The volatile profile during roasting of cashews can be used to determine the best roasting time for each type of cashew. The rate of color development and the production of volatiles differ for the cashews from the 3 geographical locations.