Samples of hot break tomato paste were collected from commercially produced aseptic totes after 6-11 months of storage at ambient temperature. Serum viscosity of the hot break tomato paste samples was analyzed at each...Samples of hot break tomato paste were collected from commercially produced aseptic totes after 6-11 months of storage at ambient temperature. Serum viscosity of the hot break tomato paste samples was analyzed at each sampling time and compared to the initial serum viscosity measured at the time of tomato paste manufacturing. As storage time increased, the serum viscosity of hot break tomato paste significantly decreased. After 7 months of storage, 16%-27% reduction of serum viscosity was observed in the hot break tomato paste. To evaluate effects of a heating on the serum viscosity of hot break tomato paste, the paste samples were reconstituted with water to 10° Brix, similar level of tomato solids in typical tomato sauce products. Diluted tomato paste was heated and held at 95℃ for 3 minutes and its serum viscosity was measured. After the heating, the serum viscosity of hot break tomato paste was slightly increased up to 5% of initial value, however the recovery was not significant （p 〈 0.05）.展开更多
An attempt has been made to improve the paste stabilities both in viscosity of a hot starch paste and in phase of a starch-polyvinyl alcohol blend paste for warp sizing. The phase stability was evaluated in terms of t...An attempt has been made to improve the paste stabilities both in viscosity of a hot starch paste and in phase of a starch-polyvinyl alcohol blend paste for warp sizing. The phase stability was evaluated in terms of the initial demixing time, and the volume percentage of polyvinyl alcohol separated. It was found that starch cross-linking is harmful to the phase stability of a starch-polyvinyl alcohol blend paste no matter what a type of polyvinyl alcohol is used, although the cross-linking is an effective technique for stabilizing the viscosity of a hot starch paste. The separation rate and extent all increase with the increase in the cross-linking degree of starch. However, this defect can be eliminated through introducing quaternary ammonium groups into crosslinked starch molecules. Evident effect can be achieved when the degree of substitution is as less as 0.021. Generally, increase in the DS reduces the separation rate and extent, and thereby raising the phase stability. Moreover, the effects of both starch content and PVA type on the separation are also considered. Cationization after starch cross-linking shows improved stabilities both in viscosity and phase.展开更多
文摘Samples of hot break tomato paste were collected from commercially produced aseptic totes after 6-11 months of storage at ambient temperature. Serum viscosity of the hot break tomato paste samples was analyzed at each sampling time and compared to the initial serum viscosity measured at the time of tomato paste manufacturing. As storage time increased, the serum viscosity of hot break tomato paste significantly decreased. After 7 months of storage, 16%-27% reduction of serum viscosity was observed in the hot break tomato paste. To evaluate effects of a heating on the serum viscosity of hot break tomato paste, the paste samples were reconstituted with water to 10° Brix, similar level of tomato solids in typical tomato sauce products. Diluted tomato paste was heated and held at 95℃ for 3 minutes and its serum viscosity was measured. After the heating, the serum viscosity of hot break tomato paste was slightly increased up to 5% of initial value, however the recovery was not significant （p 〈 0.05）.
文摘An attempt has been made to improve the paste stabilities both in viscosity of a hot starch paste and in phase of a starch-polyvinyl alcohol blend paste for warp sizing. The phase stability was evaluated in terms of the initial demixing time, and the volume percentage of polyvinyl alcohol separated. It was found that starch cross-linking is harmful to the phase stability of a starch-polyvinyl alcohol blend paste no matter what a type of polyvinyl alcohol is used, although the cross-linking is an effective technique for stabilizing the viscosity of a hot starch paste. The separation rate and extent all increase with the increase in the cross-linking degree of starch. However, this defect can be eliminated through introducing quaternary ammonium groups into crosslinked starch molecules. Evident effect can be achieved when the degree of substitution is as less as 0.021. Generally, increase in the DS reduces the separation rate and extent, and thereby raising the phase stability. Moreover, the effects of both starch content and PVA type on the separation are also considered. Cationization after starch cross-linking shows improved stabilities both in viscosity and phase.
