Wheat allergy has become a serious health threat worldwide and its prevalence has increased alarmingly in the past few years.Factors such as food matrix and food processing may alter the structure of wheat proteins,an...Wheat allergy has become a serious health threat worldwide and its prevalence has increased alarmingly in the past few years.Factors such as food matrix and food processing may alter the structure of wheat proteins,and hence affect its allergenic properties.However,few reports have focused on the influence of Chinese traditional starter fermentation on wheat allergy.In this study,5 starters from different regions of China were used for fermentation,and protein characteristics were monitored by sodium dodecyl sulfate polyacrylamide gel electropheresis,and immunoreactivity analyzed by immunoassay with allergenic serum was obtained from New Zealand white rabbits.The allergenicity of steamed and baked matrices was also evaluated.The results showed that the allergenicity of wheat dough was basically increased at the beginning and then decreased during fermentation,but specific trends depend on different starters.With the progress of fermentation,especially as pH value decreased to 3.0-4.0,the allergenicity decreased significantly.Baking and steaming can reduce the allergenicity of wheat matrix,but fermentation is not a key factor affecting the allergenic activity of proteins.Our results can provide a theoretical basis for controlling wheat allergenicity in food proces sing or producing hypoallergenic food.展开更多
This study was conducted to determine the effect of different starter diets and different amounts of milk on growth performance and gastrointestinal tract development in unweaned calves. 16 calves were assigned to 4 g...This study was conducted to determine the effect of different starter diets and different amounts of milk on growth performance and gastrointestinal tract development in unweaned calves. 16 calves were assigned to 4 groups, 4 calves in each group. These four groups received the following treatments respectively: 1) high milk (6 L) + low starch (21%), high NDF (28%), high molasses (10%) starter (HMLS group);2) high milk (6L) + high starch (40%), low NDF (14%), low molasses (5%) starter (HMHS group);3) low milk (3 L) + low starch (21%), high NDF (28%), high molasses (10%) starter (LMLS group);4) low milk (3 L) + high starch (40%), low NDF (14%), low molasses (5%) starter (LMHS group). The trial was of 2 × 2 factorial design. All calves had free access to hay and water. Results showed that the low milk allowance increased calf concentrate dry matter intake (DMI) and total DMI, reduced body height at 4 weeks of age, reduced heart girth at 6 weeks of age (P < 0.05). The low milk allowance increased complex stomach full weight, reticulorumen full weight, and the percentages of stomach full weight and reticulorumen full weight over body weight (P < 0.05). The low starch, high fiber, high molasses starters reduced the complex stomach full weight, the proportion of the complex stomach empty weight over body weight, reticulorumen empty weight, abomasum full weight, the proportion of abomasum empty weight over body weight and reticulorumen volume (P < 0.05). The low milk allowance increased calf intestine length, small intestine full weight, the proportion of small intestine full weight over body weight, but reduced the jejunum villus width (P < 0.05), increased ruminal pH (P < 0.05). The low milk allowance reduced papilla length in rumen anterior ventral blind sac, but increased papilla length in the posterior ventral sac展开更多
Natural starters have been extensively used for many centuries to make many different fermented food products from different raw materials: Milk, meat, roots, vegetables, etc. The industrialisation of food production ...Natural starters have been extensively used for many centuries to make many different fermented food products from different raw materials: Milk, meat, roots, vegetables, etc. The industrialisation of food production at the end of the 19th century necessitated the use of regular selected starters to standardize the organoleptic characteristics of the final product. As a consequence, during the 20th century, there was a decline in the use of natural starters in Western countries except in the production of local cheeses or sourdough breads. The beginning of this new millennium has witnessed a deep change in consumer demand, in pursuit of quality, safety and pleasure. In this context, natural starters could, in the future, play an important role in the development of fermented products. However, food producers and researchers have first to cope with fundamental problems in the understanding of these complex ecosystems. The dynamic evolution of the microbial population inside the natural starter (its resilience, its genetic and physiological aptitudes) and the consequences on the product are still partially unknown. This document reviews a broad range of articles concerning the use of natural starters with a specific focus on cheeses and breads, and discusses the major stakes for local food production and the consumption of typical products.展开更多
In order to find fermentation starters that can promote rapid and effective composting of chicken manure,shorten the fermentation period,and improve the compost quality,fermentation starters with different microbial c...In order to find fermentation starters that can promote rapid and effective composting of chicken manure,shorten the fermentation period,and improve the compost quality,fermentation starters with different microbial combination ratios(C1,C2,C3,C4 and C5) were designed and fermentation experiment was carried out on these five fermentation starters,commercially available organic fertilizer starter(SS),and chicken manure without inoculating fermentation starter. In the process of the fermentation,the changes in the fermentation temperature,water content and pH value were monitored; the effects of organic manure on the germination rate and growth of rapeseed seeds were measured;viable count,water content,and pH value of prepared fermentation starters were measured; main indicators( organic matter,nitrogen,phosphorus,and potassium) of organic fertilizer generated from fermentation were measured. From the indicators,the formula C3 and C4 were better,in the beginning of fermentation,the temperature rose rapidly,and it reached 40 ℃ in the second day; the water content dropped to below 35% in the 18 th day; the pH value underwent the process of declining-rising-stable,and the overall value showed slight rise,but the change was not great( 0-0. 5). C3 and C4 fermentation products had better effects on the germination and growth of rapeseeds. The germination rate of the rapeseed seeds was 100% and 97. 5% and the bud length was 15. 94 mm and 14. 57 mm,respectively,and the root length was45. 97 mm and 39. 44 mm,respectively. The content of organic matter in fermented organic manure was 86. 62% and 85. 17% respectively,and the total content of nitrogen,phosphorus and potassium was 8. 85% and 8. 22% respectively,and the pH was 7. 5 and 8. 0 respectively.All of these complied with the industry standard NY525-2012( organic matter ≥ 45%,and nitrogen,phosphorus,and potassium ≥ 5%,pH 5. 5-8. 5). The fermentation of fresh chicken manure was completed within 20 days,conforming to the requirements of large-scale organic fertilizer production factory for composting chicken manure into organic fertilizer.展开更多
Background and objectives:Extensive research studies worldwide have discussed and analyzed the sourdough nutritional,chemical,and biotechnological aspects of western types of bread.However,the literature on sourdough ...Background and objectives:Extensive research studies worldwide have discussed and analyzed the sourdough nutritional,chemical,and biotechnological aspects of western types of bread.However,the literature on sourdough usage in Arabic bread processing is very limited.The present study aimed to come up with a new fermentation technique at the bakery level.The new technique is hoped to reveal the traditional nostalgic characteristic flavor of Arabic bread produced using natural sourdough instead of the traditional yeasted dough and study its effect on the resulting bread.Three types of flour(straight grade,whole wheat,and rye)that are ordinarily used in Jordan were used to prepare three natural sour starters using the backslopping technique.Findings:Dominant yeast species isolated from the traditional sour starter of the local Jordanian whole wheat were Saccharomyces cerevisiae,Candida glabrata,and Zygosaccharomyces spp.,while rye and straight-grade starters showed different domination patterns.The dominant species of lactic acid bacteria(LAB)isolated from the traditional sour starter of the local Jordanian whole wheat(Horani cultivar)were Lactiplantibacillus plantarum2,Lactobacillus delbrueckii ssp bulgaricus,and the Lacticaseibacillus paracasei ssp paracasei3,while mixed strains of LAB isolates were obtained for the rye and straight-grade flour starters on day 7 of preparation.The pH results showed no significant differences(P>0.05)between the three types of sour starters,while the total titratable acidity(TTA)results showed a significant increase(P≤0.05)in whole wheat sour starters with a TTA value of 11.17±0.11 ml 0.1 N NaOH/10g dough.The 20%and 30%straight-grade sour bread samples and the control exhibited the highest scores in terms of acceptability and total quality scores.Conclusions:The incorporation of sourdough in Arabic flatbread processing showed remarkable results in extending the shelf life by using natural ingredients,improving the quality,and providing tastier and more convenient bread.展开更多
The traditional natural Jiuqu for brewing hulless barley wine contains a variety of complex microorganisms and enzymes.The uncertainty of microbial composition in Jiuqu and the existence of some miscellaneous microorg...The traditional natural Jiuqu for brewing hulless barley wine contains a variety of complex microorganisms and enzymes.The uncertainty of microbial composition in Jiuqu and the existence of some miscellaneous microorganisms are not conducive to the production of high-quality hulless barley wine.In order to improve the flavor quality of hulless barley wine,the mixed starter was designed to reconstruct the fermentation microbial flora.Mold strains with high saccharification ability and yeast strains with good fermentation performance were screened from the traditional natural Jiuqu for brewing hulless barley wine and were identified.And then,mixed starters by molds and yeasts were used to ferment hulless barley wines on a laboratory scale.The physicochemical indexes,sensory evaluation,volatile flavor compounds and electronic nose(E-nose)analysis of hulless barley wine brewed by different combinations of mold and yeast were analyzed.The hulless barley wine(W4 wine)brewed by the mixed starter Q4,which combined by Rhizopus oryzae,Saccharomyces cerevisiae and Wickerhamomyces anomalus,had the best volatile flavor and sensory score.This improvement was mainly reflected in the higher content of esters(252.62±0.02 mg/L)and alcohols(72.77±2.03 mg/L),with esters accounting for 67.37%of the volatile flavor compounds.In addition,the sensory score of"bitter"was the lowest in W4 wine while the scores of"sweet","wine-aroma"and"fruit-aroma"were the highest.These results demonstrated that the mixed starter Q4 could effectively improve the flavor of hulless barley wine.展开更多
Refined rice flour and wholegrain quinoa and buckwheat flours were used to prepare gluten-free sourdoughs.Two autochthonous LAB strains were isolated,one from quinoa (Limosilactobacillus fermentum Q3) and the other fr...Refined rice flour and wholegrain quinoa and buckwheat flours were used to prepare gluten-free sourdoughs.Two autochthonous LAB strains were isolated,one from quinoa (Limosilactobacillus fermentum Q3) and the other from buckwheat (Lim.fermentum T5).Lactiplantibacillus plantarum ATCC8014 was used as a reference starter.Two fermentation processes were evaluated,a single-step process (30℃,24 h) named SD1,and a daily refreshment process (backslopping for 10 days) named SD2.Sourdoughs were freeze-dried prior to analyses.Pasting properties,pentosan and polyphenol contents,and antioxidant activity were analysed.Flour properties were significantly modified by fermentation.Polyphenol extractability increased during fermentation,which resulted in a higher antioxidant capacity,mainly through a reducing mechanism.Q3 and T5 strains produced the most remarkable modifications of flour properties.Differences were found between both fermentation processes,mainly as a result of the development of different microbiota.The single-step fermentation (SD1) showed to be a simple and appropriate method for improving flour properties.展开更多
Mold spoilage and nutrition enrichment are major concerns of Chinese steamed bread,and using functional lactic acid bacteria as starter to play the role of in-situ preservation and nutritional fortification was a prom...Mold spoilage and nutrition enrichment are major concerns of Chinese steamed bread,and using functional lactic acid bacteria as starter to play the role of in-situ preservation and nutritional fortification was a promising alternative.Hence,Lactiplantibacillus plantarum P10 capable of inhibiting spoilage microorganisms and producing γ-aminobutyric acid(GABA)(380 mg/L)was screened from Chinese pickle.Metabolomics analysis showed that P10 produced key antimicrobial metabolites mainly including ten organic acids,aldehyde,alkaloid.Besides,P10 might exhibit health beneficial effects such as degrading cholesterol,lowering blood glucose and reducing uric acid due to the production of deoxycholic acid and Ile-Pro-Ile,and the degradation of purine.Finally,the promising application potential of P10 was evidenced in steamed bread with extended shelf life,excellent anti-aging effect,and 24.5-fold enrichment of GABA.Conclusively,this investigation could provide scientific basis for the application of P10 as a functional starter in steamed bread.展开更多
Although coagulase-negative Staphylococcus(CNS),along with technological activities,plays a key role in fermented sausage flavour and nutrient production,the molecular mechanism of these activities remains elusive.In ...Although coagulase-negative Staphylococcus(CNS),along with technological activities,plays a key role in fermented sausage flavour and nutrient production,the molecular mechanism of these activities remains elusive.In this study,18 CNS strains with high proteolytic activity were isolated from Chinese Dong fermented pork(Nanx Wudl),and their technological and transcriptomic properties were investigated.After biochemical identification and genetic analysis,their technological properties,including nitrate reductase,catalase,antioxidant,and lipolytic activities and their growth under varying temperatures,salt concentrations,and p H levels were evaluated.Their aroma-producing potential was also determined in a model medium resembling fermented sausages.Transcriptomic analysis was performed using the most promising isolates.Biochemical identification and 16S rDNA sequencing revealed that the 18 Staphylococcus strains belonged to Staphylococcus xylosus,Staphylococcus saprophyticus,Staphylococcus carnosus,Staphylococcus sciuri,and Staphylococcus equorum.In terms of technological properties,16 strains showed a nitrate-reducing ability,while 11 strains had a lipolytic activity.All strains exhibited superoxide dismutase(SOD)and catalase activities;four strains displayed an SOD activity of>50%.They also tolerated 10%NaCl and 150 mg/kg of nitrite.They showed significant differences in ketone and acid production.The transcriptomic analysis of S.xylosus strains Sx3 and Sx6,which were selected because of their excellent enzymatic activities and aroma-producing ability,revealed the remarkable effect of genes related to pyruvate catabolism and amino acid metabolism on aroma generation.Therefore,this study provided valuable insights into the metabolic mechanisms underlying the technological properties of CNS and identified promising candidates as starter cultures in fermented sausage manufacturing.展开更多
The basic concepts and advantages of more/all electric aircraft （M/AEA） are briefly addressed. The combined starter/generator （CS/G） system is introduced as a key technology to enable M/AEA. Some important perform...The basic concepts and advantages of more/all electric aircraft （M/AEA） are briefly addressed. The combined starter/generator （CS/G） system is introduced as a key technology to enable M/AEA. Some important performance requirements for CS/G system are obtained. Based on these requirements, a high speed switched reluctance machine （SRM） is designed to operate as a starter/generator. The entire design process is mainly divided into two stages： electromagnetic design and thermal design. In electromagnetic design stage, the electromagnetic structure and dimensions of the machine and the number of phase winding turns per pole are obtained; the topology and main technical details of the converter are briefly introduced as well. In thermal design stage, a liquid-cooling system is designed based on the thermal analysis of the machine. In the end, the performances of the designed SRM are basically verified by simulation. To get high performances, the exciting angles are optimized in two different operating modes respectively, and the optimized performances in the motoring mode are given as well.展开更多
This paper focuses on the simulation and test of the switched reluctance starter/generator systems. Through the emulational analysis of the initial starting torque, the optimal turn-on section of the power switches is...This paper focuses on the simulation and test of the switched reluctance starter/generator systems. Through the emulational analysis of the initial starting torque, the optimal turn-on section of the power switches is discovered. The fundamental theory of the generating operation is analyzed with the linearity model, and a new method is presented based on voltage pulse width modulation for the generating mode control. Through the steady-state and optimized emulation of the output power and system efficiency, the optimizational control approach for the generating mode over a wide speed range is introduced. At last, the test of the 3KW prototype system shows that the dynamic and static performance of this system is fine.展开更多
基金supported by the National Natural Science Foundation of China(31872904)。
文摘Wheat allergy has become a serious health threat worldwide and its prevalence has increased alarmingly in the past few years.Factors such as food matrix and food processing may alter the structure of wheat proteins,and hence affect its allergenic properties.However,few reports have focused on the influence of Chinese traditional starter fermentation on wheat allergy.In this study,5 starters from different regions of China were used for fermentation,and protein characteristics were monitored by sodium dodecyl sulfate polyacrylamide gel electropheresis,and immunoreactivity analyzed by immunoassay with allergenic serum was obtained from New Zealand white rabbits.The allergenicity of steamed and baked matrices was also evaluated.The results showed that the allergenicity of wheat dough was basically increased at the beginning and then decreased during fermentation,but specific trends depend on different starters.With the progress of fermentation,especially as pH value decreased to 3.0-4.0,the allergenicity decreased significantly.Baking and steaming can reduce the allergenicity of wheat matrix,but fermentation is not a key factor affecting the allergenic activity of proteins.Our results can provide a theoretical basis for controlling wheat allergenicity in food proces sing or producing hypoallergenic food.
文摘This study was conducted to determine the effect of different starter diets and different amounts of milk on growth performance and gastrointestinal tract development in unweaned calves. 16 calves were assigned to 4 groups, 4 calves in each group. These four groups received the following treatments respectively: 1) high milk (6 L) + low starch (21%), high NDF (28%), high molasses (10%) starter (HMLS group);2) high milk (6L) + high starch (40%), low NDF (14%), low molasses (5%) starter (HMHS group);3) low milk (3 L) + low starch (21%), high NDF (28%), high molasses (10%) starter (LMLS group);4) low milk (3 L) + high starch (40%), low NDF (14%), low molasses (5%) starter (LMHS group). The trial was of 2 × 2 factorial design. All calves had free access to hay and water. Results showed that the low milk allowance increased calf concentrate dry matter intake (DMI) and total DMI, reduced body height at 4 weeks of age, reduced heart girth at 6 weeks of age (P < 0.05). The low milk allowance increased complex stomach full weight, reticulorumen full weight, and the percentages of stomach full weight and reticulorumen full weight over body weight (P < 0.05). The low starch, high fiber, high molasses starters reduced the complex stomach full weight, the proportion of the complex stomach empty weight over body weight, reticulorumen empty weight, abomasum full weight, the proportion of abomasum empty weight over body weight and reticulorumen volume (P < 0.05). The low milk allowance increased calf intestine length, small intestine full weight, the proportion of small intestine full weight over body weight, but reduced the jejunum villus width (P < 0.05), increased ruminal pH (P < 0.05). The low milk allowance reduced papilla length in rumen anterior ventral blind sac, but increased papilla length in the posterior ventral sac
文摘Natural starters have been extensively used for many centuries to make many different fermented food products from different raw materials: Milk, meat, roots, vegetables, etc. The industrialisation of food production at the end of the 19th century necessitated the use of regular selected starters to standardize the organoleptic characteristics of the final product. As a consequence, during the 20th century, there was a decline in the use of natural starters in Western countries except in the production of local cheeses or sourdough breads. The beginning of this new millennium has witnessed a deep change in consumer demand, in pursuit of quality, safety and pleasure. In this context, natural starters could, in the future, play an important role in the development of fermented products. However, food producers and researchers have first to cope with fundamental problems in the understanding of these complex ecosystems. The dynamic evolution of the microbial population inside the natural starter (its resilience, its genetic and physiological aptitudes) and the consequences on the product are still partially unknown. This document reviews a broad range of articles concerning the use of natural starters with a specific focus on cheeses and breads, and discusses the major stakes for local food production and the consumption of typical products.
基金Supported by Scientific Research Foundation of Henan Provincial Department of Education(13A180676)
文摘In order to find fermentation starters that can promote rapid and effective composting of chicken manure,shorten the fermentation period,and improve the compost quality,fermentation starters with different microbial combination ratios(C1,C2,C3,C4 and C5) were designed and fermentation experiment was carried out on these five fermentation starters,commercially available organic fertilizer starter(SS),and chicken manure without inoculating fermentation starter. In the process of the fermentation,the changes in the fermentation temperature,water content and pH value were monitored; the effects of organic manure on the germination rate and growth of rapeseed seeds were measured;viable count,water content,and pH value of prepared fermentation starters were measured; main indicators( organic matter,nitrogen,phosphorus,and potassium) of organic fertilizer generated from fermentation were measured. From the indicators,the formula C3 and C4 were better,in the beginning of fermentation,the temperature rose rapidly,and it reached 40 ℃ in the second day; the water content dropped to below 35% in the 18 th day; the pH value underwent the process of declining-rising-stable,and the overall value showed slight rise,but the change was not great( 0-0. 5). C3 and C4 fermentation products had better effects on the germination and growth of rapeseeds. The germination rate of the rapeseed seeds was 100% and 97. 5% and the bud length was 15. 94 mm and 14. 57 mm,respectively,and the root length was45. 97 mm and 39. 44 mm,respectively. The content of organic matter in fermented organic manure was 86. 62% and 85. 17% respectively,and the total content of nitrogen,phosphorus and potassium was 8. 85% and 8. 22% respectively,and the pH was 7. 5 and 8. 0 respectively.All of these complied with the industry standard NY525-2012( organic matter ≥ 45%,and nitrogen,phosphorus,and potassium ≥ 5%,pH 5. 5-8. 5). The fermentation of fresh chicken manure was completed within 20 days,conforming to the requirements of large-scale organic fertilizer production factory for composting chicken manure into organic fertilizer.
文摘Background and objectives:Extensive research studies worldwide have discussed and analyzed the sourdough nutritional,chemical,and biotechnological aspects of western types of bread.However,the literature on sourdough usage in Arabic bread processing is very limited.The present study aimed to come up with a new fermentation technique at the bakery level.The new technique is hoped to reveal the traditional nostalgic characteristic flavor of Arabic bread produced using natural sourdough instead of the traditional yeasted dough and study its effect on the resulting bread.Three types of flour(straight grade,whole wheat,and rye)that are ordinarily used in Jordan were used to prepare three natural sour starters using the backslopping technique.Findings:Dominant yeast species isolated from the traditional sour starter of the local Jordanian whole wheat were Saccharomyces cerevisiae,Candida glabrata,and Zygosaccharomyces spp.,while rye and straight-grade starters showed different domination patterns.The dominant species of lactic acid bacteria(LAB)isolated from the traditional sour starter of the local Jordanian whole wheat(Horani cultivar)were Lactiplantibacillus plantarum2,Lactobacillus delbrueckii ssp bulgaricus,and the Lacticaseibacillus paracasei ssp paracasei3,while mixed strains of LAB isolates were obtained for the rye and straight-grade flour starters on day 7 of preparation.The pH results showed no significant differences(P>0.05)between the three types of sour starters,while the total titratable acidity(TTA)results showed a significant increase(P≤0.05)in whole wheat sour starters with a TTA value of 11.17±0.11 ml 0.1 N NaOH/10g dough.The 20%and 30%straight-grade sour bread samples and the control exhibited the highest scores in terms of acceptability and total quality scores.Conclusions:The incorporation of sourdough in Arabic flatbread processing showed remarkable results in extending the shelf life by using natural ingredients,improving the quality,and providing tastier and more convenient bread.
文摘The traditional natural Jiuqu for brewing hulless barley wine contains a variety of complex microorganisms and enzymes.The uncertainty of microbial composition in Jiuqu and the existence of some miscellaneous microorganisms are not conducive to the production of high-quality hulless barley wine.In order to improve the flavor quality of hulless barley wine,the mixed starter was designed to reconstruct the fermentation microbial flora.Mold strains with high saccharification ability and yeast strains with good fermentation performance were screened from the traditional natural Jiuqu for brewing hulless barley wine and were identified.And then,mixed starters by molds and yeasts were used to ferment hulless barley wines on a laboratory scale.The physicochemical indexes,sensory evaluation,volatile flavor compounds and electronic nose(E-nose)analysis of hulless barley wine brewed by different combinations of mold and yeast were analyzed.The hulless barley wine(W4 wine)brewed by the mixed starter Q4,which combined by Rhizopus oryzae,Saccharomyces cerevisiae and Wickerhamomyces anomalus,had the best volatile flavor and sensory score.This improvement was mainly reflected in the higher content of esters(252.62±0.02 mg/L)and alcohols(72.77±2.03 mg/L),with esters accounting for 67.37%of the volatile flavor compounds.In addition,the sensory score of"bitter"was the lowest in W4 wine while the scores of"sweet","wine-aroma"and"fruit-aroma"were the highest.These results demonstrated that the mixed starter Q4 could effectively improve the flavor of hulless barley wine.
基金supported by Consejo Nacional de Investigaciones Científicas y T´ecnicas and the Agencia Nacional de Promoci´on Científica y Tecnol´ogica(PICT 2015-3803)of Argentina.
文摘Refined rice flour and wholegrain quinoa and buckwheat flours were used to prepare gluten-free sourdoughs.Two autochthonous LAB strains were isolated,one from quinoa (Limosilactobacillus fermentum Q3) and the other from buckwheat (Lim.fermentum T5).Lactiplantibacillus plantarum ATCC8014 was used as a reference starter.Two fermentation processes were evaluated,a single-step process (30℃,24 h) named SD1,and a daily refreshment process (backslopping for 10 days) named SD2.Sourdoughs were freeze-dried prior to analyses.Pasting properties,pentosan and polyphenol contents,and antioxidant activity were analysed.Flour properties were significantly modified by fermentation.Polyphenol extractability increased during fermentation,which resulted in a higher antioxidant capacity,mainly through a reducing mechanism.Q3 and T5 strains produced the most remarkable modifications of flour properties.Differences were found between both fermentation processes,mainly as a result of the development of different microbiota.The single-step fermentation (SD1) showed to be a simple and appropriate method for improving flour properties.
基金financially supported by Natural Science Foundations of Hebei Province(C2022208003)Youth Top Talent Plan in Hebei Province。
文摘Mold spoilage and nutrition enrichment are major concerns of Chinese steamed bread,and using functional lactic acid bacteria as starter to play the role of in-situ preservation and nutritional fortification was a promising alternative.Hence,Lactiplantibacillus plantarum P10 capable of inhibiting spoilage microorganisms and producing γ-aminobutyric acid(GABA)(380 mg/L)was screened from Chinese pickle.Metabolomics analysis showed that P10 produced key antimicrobial metabolites mainly including ten organic acids,aldehyde,alkaloid.Besides,P10 might exhibit health beneficial effects such as degrading cholesterol,lowering blood glucose and reducing uric acid due to the production of deoxycholic acid and Ile-Pro-Ile,and the degradation of purine.Finally,the promising application potential of P10 was evidenced in steamed bread with extended shelf life,excellent anti-aging effect,and 24.5-fold enrichment of GABA.Conclusively,this investigation could provide scientific basis for the application of P10 as a functional starter in steamed bread.
基金the financial support of the National Natural Science Foundation of China(32102016)the Taishan Industrial Experts Program。
文摘Although coagulase-negative Staphylococcus(CNS),along with technological activities,plays a key role in fermented sausage flavour and nutrient production,the molecular mechanism of these activities remains elusive.In this study,18 CNS strains with high proteolytic activity were isolated from Chinese Dong fermented pork(Nanx Wudl),and their technological and transcriptomic properties were investigated.After biochemical identification and genetic analysis,their technological properties,including nitrate reductase,catalase,antioxidant,and lipolytic activities and their growth under varying temperatures,salt concentrations,and p H levels were evaluated.Their aroma-producing potential was also determined in a model medium resembling fermented sausages.Transcriptomic analysis was performed using the most promising isolates.Biochemical identification and 16S rDNA sequencing revealed that the 18 Staphylococcus strains belonged to Staphylococcus xylosus,Staphylococcus saprophyticus,Staphylococcus carnosus,Staphylococcus sciuri,and Staphylococcus equorum.In terms of technological properties,16 strains showed a nitrate-reducing ability,while 11 strains had a lipolytic activity.All strains exhibited superoxide dismutase(SOD)and catalase activities;four strains displayed an SOD activity of>50%.They also tolerated 10%NaCl and 150 mg/kg of nitrite.They showed significant differences in ketone and acid production.The transcriptomic analysis of S.xylosus strains Sx3 and Sx6,which were selected because of their excellent enzymatic activities and aroma-producing ability,revealed the remarkable effect of genes related to pyruvate catabolism and amino acid metabolism on aroma generation.Therefore,this study provided valuable insights into the metabolic mechanisms underlying the technological properties of CNS and identified promising candidates as starter cultures in fermented sausage manufacturing.
文摘The basic concepts and advantages of more/all electric aircraft （M/AEA） are briefly addressed. The combined starter/generator （CS/G） system is introduced as a key technology to enable M/AEA. Some important performance requirements for CS/G system are obtained. Based on these requirements, a high speed switched reluctance machine （SRM） is designed to operate as a starter/generator. The entire design process is mainly divided into two stages： electromagnetic design and thermal design. In electromagnetic design stage, the electromagnetic structure and dimensions of the machine and the number of phase winding turns per pole are obtained; the topology and main technical details of the converter are briefly introduced as well. In thermal design stage, a liquid-cooling system is designed based on the thermal analysis of the machine. In the end, the performances of the designed SRM are basically verified by simulation. To get high performances, the exciting angles are optimized in two different operating modes respectively, and the optimized performances in the motoring mode are given as well.
文摘This paper focuses on the simulation and test of the switched reluctance starter/generator systems. Through the emulational analysis of the initial starting torque, the optimal turn-on section of the power switches is discovered. The fundamental theory of the generating operation is analyzed with the linearity model, and a new method is presented based on voltage pulse width modulation for the generating mode control. Through the steady-state and optimized emulation of the output power and system efficiency, the optimizational control approach for the generating mode over a wide speed range is introduced. At last, the test of the 3KW prototype system shows that the dynamic and static performance of this system is fine.
