Quality characteristics of two hybrids of the cultivated mushrooms (Agaricus bisporus) and the improvement of their shelf life using stipe trimming and gamma irradiation
Ajlouni, Said Omar.
Ph.D., The Pennsylvania State University, 1991, 156 pages.
1991
บทคัดย่อ
Various postharvest quality characteristics of two hybrids of the cultivated mushroom (Agaricus bisporus) including color, cap opening, stipe elongation, fresh weight losses, soluble sugar content, respiration rate, ethylene production, and bacterial population were evaluated during storage at 12circC for a period of ten days.
It was determined that the percentage fresh weight content in the upper stipe and the gill of U-3 hybrid was significantly greater than that of U-1 throughout the storage period. However, all other characteristics related to quality and shelf life indicated that both hybrids were equivalent.
Based on those results, one hybrid (U-1 and/or U-3) was used later in two individual studies, which examined the effect of trimming the mushroom stipe (stem) at harvest, and the application of low-dose gamma irradiation immediately after harvest on the quality and the shelf life of mushrooms.
Trimming the stipe of mushroom strains to 5 mm from the cap immediately after harvest improved mushroom shelf life as indicated by a reduced rate of browning and slower rate of maturation compared with mushrooms left with longer stipes (approx35 mm). Bacterial growth on mushrooms was not affected by trimming the stipe to 5 mm immediately after harvest, but the respiration rate was higher in short stipe mushrooms. Trimming the stipe to 5 mm reduced the yield of mushrooms by about 10%. This apparent loss could be economically acceptable considering the better quality of short stipe mushrooms, and the possibility that the removed stipes might be utilized in the canning industry.
Low dose gamma irradiation (100 krad) preserved mushroom quality and extended the storage life at 12circC. Irradiated mushroom showed lower rate of maturation and whiter color when compared with non-irradiated mushrooms. Irradiated mushrooms revealed no significant changes in the rate of moisture loss, concentration of soluble sugars, or fresh weight content of the various tissues of sporophores. Respiration rate of irradiated mushrooms was high 24 hr after irradiation and then declined markedly toward the end of the storage period.