No abstract

FD&C Yellow No. 6 and five subsidiary dyes commonly found in commercial samples of this colorant were examined to determine their thermal stability in various model systems. Differences in thermal stabilities were noted for the various subsidiary dyes. Variations in stability for samples processed in neutral and acidic solutions were noted. Samples were also processed in the presence of a reducing sugar. Possible breakdown products are discussed. Studies have shown significant differences in the stability of the major and subsidiary dyes which could have potential significance.

Four varieties of green beans, Phaseolus vulgaris L. (Lake Shasta, Lake Geneva, Slimgreen, and Cascade), grown under the same conditions were analyzed for organic acid content and pH. Each variety was comminuted and processed in TDT tubes with an FO value of 4.9 at temperatures of 240 and 280 F. All analyses were conducted in duplicate using an Automatic Organic Acid Analyzer (Waters Associates, Milford, Mass.). Differences in the organic acid content were determined statistically at the 95% significance level for each acid. The organic acid profiles for the beans showed qualitative variations which appeared to be somewhat variety dependent and changes in the acid profile to a particuler variety on processing appeared to be dependent on the variety. The effects of processing on the pH of the samples appeared to be quite similar. All varieties contained acetic, fumaric, lactic, succinic, α-ketoglutaric, malic, and citric acids both initially and after processing.

The aim of this investigation was to examine changes in organic acid concentration in carrot puree during processing at temperatures ranging from 240–300 F, with 20 F increments and an F0 equal to 4.9. Two varieties of carrots from two different geographical regions were packed in Thermal Death Time (TDT) tubes, flushed with nitrogen, sealed, and processed. Following this, analyses were conducted to determine changes in organic acid content and pH. Significant increases in pyrrolidone carboxylic acid (PCA), citric acid, fumaric acid, acetic acid, and malic acid were noted between the fresh product and product processed at 240 F. The PCA concentration was significantly affected by changes in processing temperature, while pyruvic and fumaric acids exhibited possible variations. The greatest change in pH from the fresh (unheated) product occurred with the 240 F processed product in both Texas and California samples. As the processing temperature increased, with a constant F0 value, the pH decreased. The pH readings for the carrot samples from the two different locations were similar.

The aim of this investigation was the development of a simple quality test whereby knowing the amount of glutamine present in a fresh sample of carrots and the processing temperature, the amount of PCA and perhaps the acceptability of the final product might be determined. Two different varieties of carrots from two different geographical locations were packed in TDT tubes, flushed with nitrogen and sealed. A process of Fo= 4.9 was given to each series of tubes at temperatures ranging from 240‐300°F with 20°F increments. Following this, analyses were conducted for glutamine, pyrrolidone‐carboxylic acid (PCA) and pH to determine the effect of initial concentration of glutamine and process temperature upon the formation of PCA. Taste thresholds for PCA were also determined both in model systems and in processed carrot puree. PCA formation was found to exhibit an inverse linear semilogarithmic plot with process temperature such that amounts could be predicted from initial glutamine contents for a given batch. Sensory studies indicated that the levels of PCA found in samples at the lower temperatures were near the taste thresholds established for this compound. With such results it is possible to predict the best process time and temperature for carrot puree based on the initial concentration of glutamine in order to minimize off‐flavors due to PCA formation.