Sh. Dokhani, S. Jafarian, Gh. Kabir, A. Mortazavi Beck,
Volume 11, Issue 1 (4-2007)
Abstract
To determine the preheating effect on frozen French - fries quality, four potato cultivars: Agria, Marfona, Auozonia & Auola were selected from Faridan region in Isfahan province & transferred to cold storage at
temp.=5+0.5°C and RH=85-90%. At first, some physico – chemical characteristics of potato tubers such as specific gravity and dry matter content were measured by A.O.A.C methods. Also reducing sugar contents were analyzed by “High Performance Liquid Chromatography” (HPLC). The potato strips were blanched in hot water at different condition: 70°C - 4 min, 70 °C 10 min, 95 °C - 2min and then deep - fat fried at temperature 175°C for 2 minutes. Product quality properties such as texture, color and oil absorption were determined by standard methods. The data were analyzed using a factorial experiment in a completely randomized design, and average comparisons were made by by Duncan's multiple range test (p < 0.01). The results showed that blanching at 70 °C for 10 minutes markedly improved the quality parameters. Treatment at 95 °C – 2 min did not have any significant effect on Hunter Lab color parameters compared with 70 °C – 10 min. treatment, but the texture was significantly different. The oil absorption increased in strips blanched at 95 °C for 2 minutes. The samples blanched at 70 °C – 4 min had no significant effect on the product quality. In conculsion, Agria &Auola cultivars were more suitable for manufacturing French - fries than the other two varieties.
Mrs Zahra Mehrabi, Dr Hamid Reza Eshghizadeh, Mrs Afsane Nematpour,
Volume 21, Issue 1 (6-2017)
Abstract
To determine the nitrate pollution (water, soil, and tubers) in small (< 0.5 ha), medium (0.5- 1 ha) and large (> 1 ha) size of potato fields, this study was conducted in Fereidan region of Isfahan province during growing season of 2014-2015. For this purpose, the amounts of inputs and the tuber yield were recorded in each farm. Also, average nitrate-N concentration in irrigation water, soil and tubers of different potato farms were measured before planting and after harvesting. The results showed that the average soil N-nitrate concentration in small, medium and large size farms were 16.3, 17.4 and 19.9 mg kg-1 before planting and 10.3, 13.3 and 23.3 mg kg-1 after harvesting, respectively. The average N-nitrate concentration of irrigation water in small, medium and large size farms were 36.3, 27.1 and 19.5 mg L-1 before planting and 47.6, 33.1 and 16.4 mg L-1 after harvesting, respectively. At the post-harvest time, NO3-N concentration of irrigation water were below the standard range concentration (45 mg L-1) in the all large farms while 87 % of small and 85% of medium farms had more than standard concentration. The nitrate concentrations of tubers in large-sized farms were lower than others. The tuber NO3-N concentration was affected by potato cultivar. The lowest concentration of nitrate was observed in the late-season potato cultivars (Agria). that might be associated with greater tubers yield.
