Abstract:
The objective of this research was to study the impacts of humectant and modified atmosphere packaging (MAP) on the shelf life extension of taro pie. The optimal recipe for preparing the commercial taro pie (control sample) was determined. Butter was used as fat composition in the pie crust recipe since it gave better sensory qualities when compared to margarine. Crust and filling of the taro pie had a[subscript w] value of 0.78 and 0.91, respectively. Due to the difference of a[subscript w] values between pie crust and taro filling, moisture migration between crust and filling was observed. The effect of humectants to reduce moisture migration between crust and filling was studied using various concentrations of fructose and glycerol. The result showed that replacing sucrose in the taro filling with 15% (w/w) fructose combined with 15% (w/w) glycerol could reduce a[subscript w] of taro filling from 0.91 to 0.78, while maintaining the acceptable sensory properties. Using humectant could decrease moisture migration, lipid oxidation, microbial growth and extend the shelf life of taro pie from 7 days to14 days when packaged in a polypropylene (PP) bag at 30 ํC. The effect of MAP on the shelf life of taro pie was determined. The results showed that when packaged under different gas conditions including air, air + O[subscript 2] absorber ,20CO[subscript 2] /80 N[subscript 2] , 50CO[subscript 2] / 50N[subscript 2] and 80CO[subscript 2] /20N[subscript 2] in a polyvinylidene chloride coated with oriented-PP and polyethylene (PVDC/OPP/PE)bag and stored at 30 oC the commercial taro pie had shelf life of 7 days, 21days, 14days, 28 days and 28 days, respectively, while the reduced-a[subscript w] taro pie had shelf life of 14 days, 35days, 21days, 35 days and 35 days, respectively. All MAP conditions were found the growth of aerobic microorganisms. Samples packaged in air + O[subscript 2] absorber and 80 CO[subscript 2] /20N[subscript 2] had the longest shelf life. However anaerobe was evident in the air + O[subscript 2] absorber condition