Abstract
This study was undertaken to gain a greater understanding of the effects of gamma radiation and storage at 2'C on the microbiological, sensorial and chemical quality of pico de gallo. Samples of pico de gallo were exposed to cobalt'o at a dose of I kGy. Microbiological tests showed that radiation decreased bacterial counts on TSA, APT and MRS plates. Ascorbic acid content initially decreased in response to gamma processing but minor differences were observed at the end of the study. Headspace composition was not affected by gamma radiation. In both control and radiated samples 02 concentration decreased during storage while C02 concentration increased. Sensory data for six different attributes (color, flavor, texture, odor, heat and overall acceptability) showed no difference between radiated and control samples. GC-MS results showed minor differences in flavor volatiles between radiated and control samples, and during storage. Levels of acetaldehyde and ethanol in the product were unaffected by radiation and storage. Pectin solubility was affected by radiation treatment and storage. Radiation resulted in conversion of CSP to NXP. Levels of WSP and NXP increased in both treatments during storage, while levels of CSP and OHSP decreased. Pectins were extensively demethylated, and pectin DE was unaffected by radiation and storage.
Miller, Gerald Howard (1994). Microbiological, chemical, and sensory quality changes in Pico de gallo as affected by gamma radiation. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1994 -THESIS -M6484.