บทคัดย่องานวิจัย

หมวดหมู่ : ฐานข้อมูลงานวิจัย

A Box-Behnken design for predicting the combined effects of relative humidity and temperature on antagonistic yeast population density at the surface of apples

Rachid Lahlali, Sébastien Massart, M. Najib Serrhini and M. Haïssam Jijakli

International Journal of Food Microbiology, Volume 122, Issues 1-2, 29 February 2008, Pages 100-108

2008

บทคัดย่อ

A Box-Behnken design for predicting the combined effects of relative humidity and temperature on antagonistic yeast population density at the surface of apples

The objective of this work was to develop models predicting the combined effects of relative humidity (RH, 75–98%), temperature (5–25 °C), and initial applied yeast concentration (104–108 CFU/ml) o­n the apple-surface population densities of two biocontrol agents fused against postharvest diseases; the antagonistic yeasts Pichia anomala strain K and Candida oleophila strain O. Experiments were carried out according to a Box-Behnken matrix. Multiple regression analyses showed that both models yielded a good prediction of yeast density. The effect of relative humidity appeared greater than that of temperature. The number of yeast colony-forming units per square centimeter of apple fruit surface increased with increasing relative humidity, temperature, and initial applied yeast concentration. The models predict that under optimal growth conditions (25 °C, 98%), strains O and K should reach a density of 104 CFU/cm2 when applied initially at 2 × 107 (strain O) or 107 CFU/ml (strain K). The model results suggest that rainfall was likely the principal cause of the variability of yeast efficacy reported for previous preharvest orchard trials spanning two successive years. Temperature may also contribute to this variation. The models developed here are important tools for predicting population densities of both strains o­n the apple surface within the experimental limits. The use of these results should contribute to achieving yeast densities of 104 CFU/cm2 o­n apples by controlling yeast application and environmental factors such as relative humidity and temperature. The results of this study also confirm our previous in vitro findings that water activity has a greater effect than temperature o­n yeast population density.