Shelf-life extension of aquatic products is of significant economical importance. To determine the potential effect of chitosan on the shelf-life of filleted tilapia, this study analyzed the bacterial community divers...Shelf-life extension of aquatic products is of significant economical importance. To determine the potential effect of chitosan on the shelf-life of filleted tilapia, this study analyzed the bacterial community diversity in fresh and spoiled tilapia fillets stored at (4 ± 1)℃ and examined the antimicrobial activity of chitosan against relevant bacteria isolates. Results showed that Pseudomonas (20%) and Aeromonas (16%) were abundant in fresh tilapia fillets, whereas Pseudomonas (52%), Aeromonas (32%) and Staphylococcus (12%) were dominant in the spoiled samples. Chitosan showed wide-spectrum antibacterial activity against bacteria isolated from tilapia and 5.0 g L-1 chitosan was selected for application in preservation. We further determined the shelf-life of chitosan-treated, filleted tilapia stored at (4 ± 1)℃ based on microbiological, biochemical and sensory analyses. Results showed that the shelf-life of chitosan-treated, filleted tilapia was extended to 12 d, whereas that of untreated, control samples was 6 d. These indicate that chitosan, as a natural preservative, has great application potential in the shelf-life extension of tilapia fillets.展开更多
Uni-modal rainfall pattern has long dry spell wherein sweetpotato is scarce, expensive but cheap at harvest. The crop is mostly consumed, processed or sold. Extending shelf-life of roots is crucial for Malawi and Nort...Uni-modal rainfall pattern has long dry spell wherein sweetpotato is scarce, expensive but cheap at harvest. The crop is mostly consumed, processed or sold. Extending shelf-life of roots is crucial for Malawi and Northern Ghana as the crop has high value. Trials were conducted in the countries at the community level. In the dry season, temperature is cool in Malawi while warm in Ghana, but thru harmattan, the night is cool with low relative humidity. In Malawi, orange-fleshed sweetpotato Zondeni var., white and yellow types were assessed in three types of storage, Afghan ventilated pit store, storage in dry sand of pit-steps, and of a granary In Ghana, local moistened heap and sandbox were compared. In Malawi, weight losses were calculated relative to the quantity stored at start, it was not cumulative. At 1.5 months no significant difference was among treatments. By 3.5 months the pit-steps method emerged to be superior and continued to 6.5 months. Losses in granary were due to shriveling, in the pit-stepsdue to termites and rats, and in ventilated pit due to termites, rats and Java black rot. Sprouting was high in pit-steps, but it was simply removed and roots returned to storage. At 6.5 months, the beta-carotene of Zondeni roots was traceable. Farmers gained high price when selling them as roots were scarce. Women favored the pit-steps because it was manageable. In Ghana, the sandbox was superior to local moistened heap. Methods designed were suitable for home consumption, but will require modification for commercialization.展开更多
Cereal-based foods play an important role as a source of dietary energy and nutrients in human nutrition. The use of microorganisms by humans has a long tradition. Bread making is one of the oldest arts known to man. ...Cereal-based foods play an important role as a source of dietary energy and nutrients in human nutrition. The use of microorganisms by humans has a long tradition. Bread making is one of the oldest arts known to man. Today we know that lactic acid bacteria （LAB） and yeasts are prevailing organisms in carbohydrate-rich environments. They break down carbohydrates to mainly lactic acid, ethanol and CO2. The present study is to determine the effect of Lactobacillus bulgaricus alone and as a combination with yeast （Saccharomyces cerevisiae） using yeast as a control. In this work, different percentage of Lactobacillus bulgaricus were used to investigate how sourdough affect on the bread sensory characteristics such as volume, specific loaf volume, crust, grain, color crumb, aroma, taste, texture, pH of bread and extended shelf life of bread. Also different storage times were used to know it is affected on the shelf life and sensory characteristics of bread. The results suggest that use of sourdough in bread production is useful in improving sensory properties, decreasing fungal spoilage.展开更多
Chemical application after harvest is an important method to preserve strawberry fruit quality and extend shelf life. The strawberry fruits harvested at red stage were treated with three different sources of calcium, ...Chemical application after harvest is an important method to preserve strawberry fruit quality and extend shelf life. The strawberry fruits harvested at red stage were treated with three different sources of calcium, i.e., calcium nitrate, calcium gluconate and calcium chloride at calcium concentration of 0% （distilled water）, 0.5%, 1.0% and 1.5%. The strawberry fruits were dipped for 30 s. The calcium sources, calcium concentration and the interaction of calcium sources and calcium concentration significantly affected the storage performance of strawberry fruits. All the three sources and concentrations were effective in decreasing the storage associated changes, i.e., weight loss, decline in marketable fruits, loss of organoleptic quality, increase in total soluble solids （TSS）, decline in reducing sugars, total sugars, acidity and increase in sugar/acid ratio in strawberry fruit, thus extending the shelf life. Calcium gluconate at 1.5% calcium concentration was more effective. Treatment of strawberry fruit with 1.5% calcium from calcium gluconate source resulted in the highest number of marketable fruit （100%）, extended shelf life （10 d）, and total soluble solid （7.80%） with the minimum weight loss （5.45%）. Calcium dips result in higher calcium concentration in strawberry fruits, which delays ripening in fruits by maintaining the structure and function of cell walls and membranes. It can be concluded that calcium gluconate at 1.5% concentration is an effective calcium treatment to retain the quality and extend the shelf life of strawberry fruit.展开更多
[Objective] The aim was to study on effect of maltose concentration by ultrafiltration.[Method] 40% and 15% maltose syrups were concentrated using ultrafiltration membranes at molecular weight of 6 000 Da in order to ...[Objective] The aim was to study on effect of maltose concentration by ultrafiltration.[Method] 40% and 15% maltose syrups were concentrated using ultrafiltration membranes at molecular weight of 6 000 Da in order to study on concentration effect of maltose and restoration effect of membranes property through backflushing.[Result] When 40% maltose was concentrated with the membrane,membrane flux weakened rapidly and pores blocked.In contrast,when 15% maltose was concentrated with the same membrane,the membrane flux was high and weakened very slowly.Dextrose equivalent(DE) and luminousness changed from 43% and 91%T before filtration to 50% and 98%T after filtration,respectively.[Conclusion] The research provides a practical method to improve transparency of maltose products and extend quality guarantee period.展开更多
基金supported by the Special Funds for the Basic Research and Development Program in the Central Non-profit Research Institutes of China (No.20603022011005)
文摘Shelf-life extension of aquatic products is of significant economical importance. To determine the potential effect of chitosan on the shelf-life of filleted tilapia, this study analyzed the bacterial community diversity in fresh and spoiled tilapia fillets stored at (4 ± 1)℃ and examined the antimicrobial activity of chitosan against relevant bacteria isolates. Results showed that Pseudomonas (20%) and Aeromonas (16%) were abundant in fresh tilapia fillets, whereas Pseudomonas (52%), Aeromonas (32%) and Staphylococcus (12%) were dominant in the spoiled samples. Chitosan showed wide-spectrum antibacterial activity against bacteria isolated from tilapia and 5.0 g L-1 chitosan was selected for application in preservation. We further determined the shelf-life of chitosan-treated, filleted tilapia stored at (4 ± 1)℃ based on microbiological, biochemical and sensory analyses. Results showed that the shelf-life of chitosan-treated, filleted tilapia was extended to 12 d, whereas that of untreated, control samples was 6 d. These indicate that chitosan, as a natural preservative, has great application potential in the shelf-life extension of tilapia fillets.
文摘Uni-modal rainfall pattern has long dry spell wherein sweetpotato is scarce, expensive but cheap at harvest. The crop is mostly consumed, processed or sold. Extending shelf-life of roots is crucial for Malawi and Northern Ghana as the crop has high value. Trials were conducted in the countries at the community level. In the dry season, temperature is cool in Malawi while warm in Ghana, but thru harmattan, the night is cool with low relative humidity. In Malawi, orange-fleshed sweetpotato Zondeni var., white and yellow types were assessed in three types of storage, Afghan ventilated pit store, storage in dry sand of pit-steps, and of a granary In Ghana, local moistened heap and sandbox were compared. In Malawi, weight losses were calculated relative to the quantity stored at start, it was not cumulative. At 1.5 months no significant difference was among treatments. By 3.5 months the pit-steps method emerged to be superior and continued to 6.5 months. Losses in granary were due to shriveling, in the pit-stepsdue to termites and rats, and in ventilated pit due to termites, rats and Java black rot. Sprouting was high in pit-steps, but it was simply removed and roots returned to storage. At 6.5 months, the beta-carotene of Zondeni roots was traceable. Farmers gained high price when selling them as roots were scarce. Women favored the pit-steps because it was manageable. In Ghana, the sandbox was superior to local moistened heap. Methods designed were suitable for home consumption, but will require modification for commercialization.
文摘Cereal-based foods play an important role as a source of dietary energy and nutrients in human nutrition. The use of microorganisms by humans has a long tradition. Bread making is one of the oldest arts known to man. Today we know that lactic acid bacteria （LAB） and yeasts are prevailing organisms in carbohydrate-rich environments. They break down carbohydrates to mainly lactic acid, ethanol and CO2. The present study is to determine the effect of Lactobacillus bulgaricus alone and as a combination with yeast （Saccharomyces cerevisiae） using yeast as a control. In this work, different percentage of Lactobacillus bulgaricus were used to investigate how sourdough affect on the bread sensory characteristics such as volume, specific loaf volume, crust, grain, color crumb, aroma, taste, texture, pH of bread and extended shelf life of bread. Also different storage times were used to know it is affected on the shelf life and sensory characteristics of bread. The results suggest that use of sourdough in bread production is useful in improving sensory properties, decreasing fungal spoilage.
文摘Chemical application after harvest is an important method to preserve strawberry fruit quality and extend shelf life. The strawberry fruits harvested at red stage were treated with three different sources of calcium, i.e., calcium nitrate, calcium gluconate and calcium chloride at calcium concentration of 0% （distilled water）, 0.5%, 1.0% and 1.5%. The strawberry fruits were dipped for 30 s. The calcium sources, calcium concentration and the interaction of calcium sources and calcium concentration significantly affected the storage performance of strawberry fruits. All the three sources and concentrations were effective in decreasing the storage associated changes, i.e., weight loss, decline in marketable fruits, loss of organoleptic quality, increase in total soluble solids （TSS）, decline in reducing sugars, total sugars, acidity and increase in sugar/acid ratio in strawberry fruit, thus extending the shelf life. Calcium gluconate at 1.5% calcium concentration was more effective. Treatment of strawberry fruit with 1.5% calcium from calcium gluconate source resulted in the highest number of marketable fruit （100%）, extended shelf life （10 d）, and total soluble solid （7.80%） with the minimum weight loss （5.45%）. Calcium dips result in higher calcium concentration in strawberry fruits, which delays ripening in fruits by maintaining the structure and function of cell walls and membranes. It can be concluded that calcium gluconate at 1.5% concentration is an effective calcium treatment to retain the quality and extend the shelf life of strawberry fruit.
基金Supported by Demonstration Project of Ecology Restoration on PollutedWater Area in Estuary(2010BAC68B02)
文摘[Objective] The aim was to study on effect of maltose concentration by ultrafiltration.[Method] 40% and 15% maltose syrups were concentrated using ultrafiltration membranes at molecular weight of 6 000 Da in order to study on concentration effect of maltose and restoration effect of membranes property through backflushing.[Result] When 40% maltose was concentrated with the membrane,membrane flux weakened rapidly and pores blocked.In contrast,when 15% maltose was concentrated with the same membrane,the membrane flux was high and weakened very slowly.Dextrose equivalent(DE) and luminousness changed from 43% and 91%T before filtration to 50% and 98%T after filtration,respectively.[Conclusion] The research provides a practical method to improve transparency of maltose products and extend quality guarantee period.
