This study aimed to evaluate the potential use of Thai rice for the production of prebiotic isomalto-oligosaccharides through fungal fermentation. Solid-state fermentations of two rice varieties, waxy rice RD6 and non...This study aimed to evaluate the potential use of Thai rice for the production of prebiotic isomalto-oligosaccharides through fungal fermentation. Solid-state fermentations of two rice varieties, waxy rice RD6 and non-waxy rice KDM 105 with Aspergillus oryzae TISTR 3108 were compared. The effects of the main parameters such as incubation time, temperature, pH, fungal spore inoculum size and moisture content were also studied individually to maximise the isomalto-oligosaccharides yield. Results showed that the maximum values of amylolytic activity and total reducing sugar were observed when using rice in SSF with initial moisture content of 70% and inoculated with the inoculum size of 107 spores/g. The optimal conditions of SSF were performed at initial pH 6 and 30 ~C for 5 d. SSF of waxy rice RD6 with Aspergillus oryzae produced highest concentrations of isomalto-oligosaccharides which consisted of isomaltose, panose and isomaltotriose. After fermentation, mashing was used to further hydrolyse the remaining starch in rice slurry. The subsequent rice syrup contained high amounts of isomaltose, panose and isomaltotriose with the values of 44, 10 and 7 g/L respectively.展开更多
Nitrogen is one of the most important nutrients in rice production but its uptake dynamics remained relatively unexplored. The present investigation evaluated uptake dynamics over the growing season at different level...Nitrogen is one of the most important nutrients in rice production but its uptake dynamics remained relatively unexplored. The present investigation evaluated uptake dynamics over the growing season at different levels of nitrogen fertilizer application. The experiment was conducted during Boro season （November-April） at Bangladesh Rice Research Institute experimental farm, Gazipur, Bangladesh. The experiment involved two modem rice varieties-BRRl dhan28 and BRRI dhan29 and six N rates： 0, 50, 100, 150, 200 and 250 kg·ha^-1. The N uptake pattern was determined at every 15 days from transplanting to maturity. At 150 kg·N·ha^-1, initially N uptake was 0.1 kg.hal.day1 which increased to 0.2 in BRRI dhan28 and 0.4 in BRRI dhan29, respectively. During 30 to 45 DAT, per day N uptake was 2.0 kg-ha1 in BRRI dhan28 and 2.2 in BRRI dhan29 which increased to the peak at 2.4 and 2.8 kg·ha^-1·day^-1 in BRRI dhan28 and BRRI dhan29, respectively, during 45 to 60 DAT. The grain yield showed a stronger correlation with N uptake during 45 to 60 DAT in both the varieties. The highest N uptake contributed to the highest dry matter production in both the varieties.展开更多
文摘This study aimed to evaluate the potential use of Thai rice for the production of prebiotic isomalto-oligosaccharides through fungal fermentation. Solid-state fermentations of two rice varieties, waxy rice RD6 and non-waxy rice KDM 105 with Aspergillus oryzae TISTR 3108 were compared. The effects of the main parameters such as incubation time, temperature, pH, fungal spore inoculum size and moisture content were also studied individually to maximise the isomalto-oligosaccharides yield. Results showed that the maximum values of amylolytic activity and total reducing sugar were observed when using rice in SSF with initial moisture content of 70% and inoculated with the inoculum size of 107 spores/g. The optimal conditions of SSF were performed at initial pH 6 and 30 ~C for 5 d. SSF of waxy rice RD6 with Aspergillus oryzae produced highest concentrations of isomalto-oligosaccharides which consisted of isomaltose, panose and isomaltotriose. After fermentation, mashing was used to further hydrolyse the remaining starch in rice slurry. The subsequent rice syrup contained high amounts of isomaltose, panose and isomaltotriose with the values of 44, 10 and 7 g/L respectively.
文摘Nitrogen is one of the most important nutrients in rice production but its uptake dynamics remained relatively unexplored. The present investigation evaluated uptake dynamics over the growing season at different levels of nitrogen fertilizer application. The experiment was conducted during Boro season （November-April） at Bangladesh Rice Research Institute experimental farm, Gazipur, Bangladesh. The experiment involved two modem rice varieties-BRRl dhan28 and BRRI dhan29 and six N rates： 0, 50, 100, 150, 200 and 250 kg·ha^-1. The N uptake pattern was determined at every 15 days from transplanting to maturity. At 150 kg·N·ha^-1, initially N uptake was 0.1 kg.hal.day1 which increased to 0.2 in BRRI dhan28 and 0.4 in BRRI dhan29, respectively. During 30 to 45 DAT, per day N uptake was 2.0 kg-ha1 in BRRI dhan28 and 2.2 in BRRI dhan29 which increased to the peak at 2.4 and 2.8 kg·ha^-1·day^-1 in BRRI dhan28 and BRRI dhan29, respectively, during 45 to 60 DAT. The grain yield showed a stronger correlation with N uptake during 45 to 60 DAT in both the varieties. The highest N uptake contributed to the highest dry matter production in both the varieties.
