The objective was to study the sensory attributes of organic leafy greens treated with plant antimicrobials and identify treatments most accepted by panelists. Organic leafy greens were washed with antimicrobials and ...The objective was to study the sensory attributes of organic leafy greens treated with plant antimicrobials and identify treatments most accepted by panelists. Organic leafy greens were washed with antimicrobials and stored at 4°C for 24 h prior to serving panelists. Antimicrobials evaluated include: 0.1% clove bud, lemongrass, oregano, or cinnamon essential oils;0.1% carvacrol or citral;3% grapeseed, apple, or 10%/7% olive extract;combination of essential oils with extracts;3% hydrogen peroxide;and untreated control. A randomized block design with an affective test was used and 60 panelists were asked to evaluate samples for preference liking based on a 9-point hedonic scale and for sensory attributes based on a 5-point hedonic scale. Changes in texture and color of leafy greens were measured using a Texture analyzer and a Chroma Meter, respectively. On the basis of preference liking, overall acceptability of spinach and lettuce treated with 0.1% cinnamon oil was ranked the highest (7.5 ± 1.4 and 7.1 ± 1.7, moderately liked), respectively. For texture analysis, washing iceberg lettuce with 0.1% oregano oil + 10% olive extract and spinach with 0.1% lemongrass oil + 1% apple extract yielded the highest firmness values of F = 783.1 ± 53.8 Newtons and 939.30 ± 35.2 Newtons, respectively. Based on the International Commission on Illumination CIE LAB color schemes, treatment with 0.1% oregano oil + 10% olive extract had the greatest impact on color of iceberg lettuce with the lowest L value* (44.5 ± 6.2) indicating the darkest color. These results will help identify plant antimicrobials that have the least impact on sensory properties of organic leafy greens and are preferred by consumers.展开更多
Bioconversion of lignocellulosic biomass to ethanol is significantly hindered by the structural and chemical complexity of biomass,which makes these materials a challenge to be used as feedstocks for cellulosic ethano...Bioconversion of lignocellulosic biomass to ethanol is significantly hindered by the structural and chemical complexity of biomass,which makes these materials a challenge to be used as feedstocks for cellulosic ethanol production.Cellulose and hemicellulose,when hydrolyzed into their component sugars,can be converted into ethanol through well established fermentation technologies.However,sugars necessary for fermentation are trapped inside the crosslinking structure of the lignocellulose.Hence,pretreatment of biomass is always necessary to remove and/or modify the surrounding matrix of lignin and hemicellulose prior to the enzymatic hydrolysis of the polysaccharides(cellulose and hemicellulose)in the biomass.Pretreatment refers to a process that converts lignocellulosic biomass from its native form,in which it is recalcitrant to cellulase enzyme systems,into a form for which cellulose hydrolysis is much more effective.In general,pretreatment methods can be classified into three categories,including physical,chemical,and biological pretreatment.The subject of this paper emphasizes the biomass pretreatment in preparation for enzymatic hydrolysis and microbial fermentation for cellulosic ethanol production.It primarily covers the impact of biomass structural and compositional features on the pretreatment,the characteristics of different pretreatment methods,the pretreatment study status,challenges,and future research targets.展开更多
文摘The objective was to study the sensory attributes of organic leafy greens treated with plant antimicrobials and identify treatments most accepted by panelists. Organic leafy greens were washed with antimicrobials and stored at 4°C for 24 h prior to serving panelists. Antimicrobials evaluated include: 0.1% clove bud, lemongrass, oregano, or cinnamon essential oils;0.1% carvacrol or citral;3% grapeseed, apple, or 10%/7% olive extract;combination of essential oils with extracts;3% hydrogen peroxide;and untreated control. A randomized block design with an affective test was used and 60 panelists were asked to evaluate samples for preference liking based on a 9-point hedonic scale and for sensory attributes based on a 5-point hedonic scale. Changes in texture and color of leafy greens were measured using a Texture analyzer and a Chroma Meter, respectively. On the basis of preference liking, overall acceptability of spinach and lettuce treated with 0.1% cinnamon oil was ranked the highest (7.5 ± 1.4 and 7.1 ± 1.7, moderately liked), respectively. For texture analysis, washing iceberg lettuce with 0.1% oregano oil + 10% olive extract and spinach with 0.1% lemongrass oil + 1% apple extract yielded the highest firmness values of F = 783.1 ± 53.8 Newtons and 939.30 ± 35.2 Newtons, respectively. Based on the International Commission on Illumination CIE LAB color schemes, treatment with 0.1% oregano oil + 10% olive extract had the greatest impact on color of iceberg lettuce with the lowest L value* (44.5 ± 6.2) indicating the darkest color. These results will help identify plant antimicrobials that have the least impact on sensory properties of organic leafy greens and are preferred by consumers.
文摘Bioconversion of lignocellulosic biomass to ethanol is significantly hindered by the structural and chemical complexity of biomass,which makes these materials a challenge to be used as feedstocks for cellulosic ethanol production.Cellulose and hemicellulose,when hydrolyzed into their component sugars,can be converted into ethanol through well established fermentation technologies.However,sugars necessary for fermentation are trapped inside the crosslinking structure of the lignocellulose.Hence,pretreatment of biomass is always necessary to remove and/or modify the surrounding matrix of lignin and hemicellulose prior to the enzymatic hydrolysis of the polysaccharides(cellulose and hemicellulose)in the biomass.Pretreatment refers to a process that converts lignocellulosic biomass from its native form,in which it is recalcitrant to cellulase enzyme systems,into a form for which cellulose hydrolysis is much more effective.In general,pretreatment methods can be classified into three categories,including physical,chemical,and biological pretreatment.The subject of this paper emphasizes the biomass pretreatment in preparation for enzymatic hydrolysis and microbial fermentation for cellulosic ethanol production.It primarily covers the impact of biomass structural and compositional features on the pretreatment,the characteristics of different pretreatment methods,the pretreatment study status,challenges,and future research targets.
