With the aim of to valorise red grape pomace and to reduce its environmental impact, the production of enzymatic preparations appear as an interesting choice. Statistical experimental Plackett-Burman designs were appl...With the aim of to valorise red grape pomace and to reduce its environmental impact, the production of enzymatic preparations appear as an interesting choice. Statistical experimental Plackett-Burman designs were applied for the selection of relevant medium components and culture conditions for cellulase, xylanase, polygalacturonase and tannase production by Aspergillus awamori, in solid-state fermentation on red grape pomace. Ten variables were tested： initial moisture content （IMC）, particle size （PS）, temperature, initial pH, time of cultivation, mixing （Mx）, and additions of： fructose, tannic acid, sodium phosphate, and ammonium sulphate （ASA）. Results indicate that the production of each enzyme was affected in a distinct way by the different variables. Also, for each of the enzyme activities considered, IMC must be carefully controlled, and optimized above 65%; PS and Mx, must not be taken into account and ASA must be discarded. The other variables studied, must be selected according to the enzyme activity that will be favored.展开更多
The aim was to research fresh-keeping effects of natamycin on cold-pre- served grape. Red globe grapes were processed with compound coating liquid of chitosan with mass fraction at 1% and natamycin with mass fractions...The aim was to research fresh-keeping effects of natamycin on cold-pre- served grape. Red globe grapes were processed with compound coating liquid of chitosan with mass fraction at 1% and natamycin with mass fractions at 0.20% （T1）, 0.40% （T2） and 0.60% （T3）, respectively. Grapes processed with water （CK3） and 1% chitosan （CK2） were taken as control groups. Rotten rate, seed shattering rate, mass loss rate, respiratory intensity and related physiological quality in test and control groups were compared. The results indicated that respiratory intensity, mass loss rate, rotten rate and seed shattering rate in CK1 were all higher than those in CK2. In addition, T1, T2 and T3 were lower in the indices than CK1 and CK2, but still kept at a high level in fruit hardness. Furthermore, mass fractions of Vc and titratable acid declined more slowly in T1, T2 and T3, compared with CK1 and CK2. Natamycin better preserved grapes and prolonged storage period. In general, natamycin with mass fraction at 0.4% proved best in fresh-keeping.展开更多
The equations for predicting the electrical conductivities of red grape juice at different concentrations have been evaluated in this study.Three samples of red grape juice having concentrations of 10.5,12.5 and 14.5&...The equations for predicting the electrical conductivities of red grape juice at different concentrations have been evaluated in this study.Three samples of red grape juice having concentrations of 10.5,12.5 and 14.5°Brix were ohmically heated by applying three different voltage gradients(10,12 and 15 V/cm)in the temperature range of 25-80℃.The mathematical models using multiple linear regression analysis indicated that electrical conductivity depended on temperature and concentration.The predictions of electrical conductivities using the mathematical models was found to be highly accurate with R2 value of 0.9975 when compared with the experimental data of red grape juice with concentration of 11.5°Brix.The reducing chi-square(χ^(2))and the root mean square error(RMSE)from the mathematical models were calculated and compared with the experimental data.As the results,multiple linear regressions on the coefficients of the mathematical model of electrical conductivity prediction have given highest values of the R2 and lowestχ^(2)and RMSE so the established model was confirmed as highly accurate when estimating electrical conductivities of red grape juice.展开更多
Packaging material has an important role in extending the shelf-life of fruits.This study investigated the effectiveness of cellulose nanocrystals(CNCs)derived from Kudzu(Pueraria montana)vine to reinforce to starch-b...Packaging material has an important role in extending the shelf-life of fruits.This study investigated the effectiveness of cellulose nanocrystals(CNCs)derived from Kudzu(Pueraria montana)vine to reinforce to starch-based films.In addition,the essential oil was incorporated into these nanocomposite films to evaluate further improvement in film properties and applications.Different packaging materials,including the pearl millet starch(PMS),PMS reinforced with Kudzu CNCs,and PMS reinforced with Kudzu CNCs stabilized pickering emulsion containing clove bud oil(CBO),was used to develop biodegradable nanocomposite films.The films were investigated for their thermal,morphological,mechanical,and barrier properties.In addition,the films were used as packaging material to improve the shelf life of the grapes for 15 days at 5℃.PMS films reinforced with Kudzu CNCs stabilized pickering emulsion of CBO were most effective in extending the shelf life of red grapes up to 15 days at 5℃ by maintaining the weight,firmness,and soluble solids in grapes for a longer duration during storage.The study suggests that PMS+Kudzu CNCs+EO films have the potential for commercial packaging of fruits during short storage periods without adversely affecting their quality and sensory attributes.展开更多
文摘With the aim of to valorise red grape pomace and to reduce its environmental impact, the production of enzymatic preparations appear as an interesting choice. Statistical experimental Plackett-Burman designs were applied for the selection of relevant medium components and culture conditions for cellulase, xylanase, polygalacturonase and tannase production by Aspergillus awamori, in solid-state fermentation on red grape pomace. Ten variables were tested： initial moisture content （IMC）, particle size （PS）, temperature, initial pH, time of cultivation, mixing （Mx）, and additions of： fructose, tannic acid, sodium phosphate, and ammonium sulphate （ASA）. Results indicate that the production of each enzyme was affected in a distinct way by the different variables. Also, for each of the enzyme activities considered, IMC must be carefully controlled, and optimized above 65%; PS and Mx, must not be taken into account and ASA must be discarded. The other variables studied, must be selected according to the enzyme activity that will be favored.
文摘The aim was to research fresh-keeping effects of natamycin on cold-pre- served grape. Red globe grapes were processed with compound coating liquid of chitosan with mass fraction at 1% and natamycin with mass fractions at 0.20% （T1）, 0.40% （T2） and 0.60% （T3）, respectively. Grapes processed with water （CK3） and 1% chitosan （CK2） were taken as control groups. Rotten rate, seed shattering rate, mass loss rate, respiratory intensity and related physiological quality in test and control groups were compared. The results indicated that respiratory intensity, mass loss rate, rotten rate and seed shattering rate in CK1 were all higher than those in CK2. In addition, T1, T2 and T3 were lower in the indices than CK1 and CK2, but still kept at a high level in fruit hardness. Furthermore, mass fractions of Vc and titratable acid declined more slowly in T1, T2 and T3, compared with CK1 and CK2. Natamycin better preserved grapes and prolonged storage period. In general, natamycin with mass fraction at 0.4% proved best in fresh-keeping.
文摘The equations for predicting the electrical conductivities of red grape juice at different concentrations have been evaluated in this study.Three samples of red grape juice having concentrations of 10.5,12.5 and 14.5°Brix were ohmically heated by applying three different voltage gradients(10,12 and 15 V/cm)in the temperature range of 25-80℃.The mathematical models using multiple linear regression analysis indicated that electrical conductivity depended on temperature and concentration.The predictions of electrical conductivities using the mathematical models was found to be highly accurate with R2 value of 0.9975 when compared with the experimental data of red grape juice with concentration of 11.5°Brix.The reducing chi-square(χ^(2))and the root mean square error(RMSE)from the mathematical models were calculated and compared with the experimental data.As the results,multiple linear regressions on the coefficients of the mathematical model of electrical conductivity prediction have given highest values of the R2 and lowestχ^(2)and RMSE so the established model was confirmed as highly accurate when estimating electrical conductivities of red grape juice.
基金supported by the Dr.Whiteside Laboratory in the Department of Food,Nutrition,and Packaging Science,Clemson University.
文摘Packaging material has an important role in extending the shelf-life of fruits.This study investigated the effectiveness of cellulose nanocrystals(CNCs)derived from Kudzu(Pueraria montana)vine to reinforce to starch-based films.In addition,the essential oil was incorporated into these nanocomposite films to evaluate further improvement in film properties and applications.Different packaging materials,including the pearl millet starch(PMS),PMS reinforced with Kudzu CNCs,and PMS reinforced with Kudzu CNCs stabilized pickering emulsion containing clove bud oil(CBO),was used to develop biodegradable nanocomposite films.The films were investigated for their thermal,morphological,mechanical,and barrier properties.In addition,the films were used as packaging material to improve the shelf life of the grapes for 15 days at 5℃.PMS films reinforced with Kudzu CNCs stabilized pickering emulsion of CBO were most effective in extending the shelf life of red grapes up to 15 days at 5℃ by maintaining the weight,firmness,and soluble solids in grapes for a longer duration during storage.The study suggests that PMS+Kudzu CNCs+EO films have the potential for commercial packaging of fruits during short storage periods without adversely affecting their quality and sensory attributes.
