Study On Sterilization Effect And Quality Of Edible Areca Nut By⁶⁰Co γ Ray Irradiation

Edible areca nut is the areca nut processed by infusing, cutting, spicing, drying, etc. Due to its unique flavor and good chewiness, edible areca nut is very popular with consumers. Microorganism contamination and massive addition of antiseptic during processing of areca nut had generated a considerable concern in the public. This study focused on microorganism contamination of present edible areca nut, disinfectant dosage of60Co y ray and effect of60Co y ray on quality of edible areca nut. The results were as follows:(1) Edible areca nut sold in Changsha, Hunan was random sampled for studying the microbial pollution situation, and32kinds of bacteria and14kinds of fungi were separated and purificated. Identification was proceeded by morphological characteristic and physiological and biochemical reaction, and16S rDNA and ITS sequence analysis, found that most of bacteria and fungi were identified as bacilli and mould, respectively. And two kinds of microorganisms Rhodococcus corynebacterioid.es and Aspergillus flavus were accurately identified.(2) The disinfectant effect of60Coγ ray on edible areca nut was significant. When the absorbed dose was3.65kGy, the initial total bacterial count reduced from5.8×105CFU/g to1.1×103CFU/g, and the count of mould and coliform bacteria was less than10CFU/g and10MPN/g, respectively. D10value of the irradiation for sterilization of edible areca nut was1.53kGy. The shelf life of edible areca nut irradiated with60Coγ ray increased obviously. Consequently, the lowest effective dose of the irradiation for sterilization of edible areca nut was determined as3.65kGy.(3)60Coγ ray had no significant influence on the content of water, ash, protein and fat, but had significant influence on the content of total sugar and total phenol and pH value. The irradiation would not affect appearance, fragrance, flavor, taste and acceptability of edible areca nut when the absorbed dose was lower than9.77kGy. Consequently, the maximum tolerance dose of the irradiation for sterilization of edible areca nut was determined as9.77kGy.(4)60Coγ ray had apparent effect on particle size distribution and microstructure of areca nut fibre. The60Coy ray irradiation decreased the particle size of areca nut fibre with the increase of irradiation dose. Both water and pretreatment with NaOH aggravated the damage effect of irradiation on areca nut fibre.