采用顶空固相微萃取结合气质联用(headspace-solid phase microextraction coupled with gas chromatography-mass spectrometry,SPME-GC/MS)技术,对常温贮存下羊奶粉中挥发性成分进行提取与分析。在常温贮存1年的羊奶粉中,共检出41种...采用顶空固相微萃取结合气质联用(headspace-solid phase microextraction coupled with gas chromatography-mass spectrometry,SPME-GC/MS)技术,对常温贮存下羊奶粉中挥发性成分进行提取与分析。在常温贮存1年的羊奶粉中,共检出41种挥发性成分。其中酸类成分最多,共13种,其次是酯类、烃类、醇类和醛酮类,分别为6、4、4和3种。羊奶粉的主体挥发性成分组成是丁酸、己酸、庚酸、辛酸、4-甲基辛酸、癸酸、月桂酸、邻苯二甲酸二甲酯、辛酸乙酯、十五烷、苯甲醛、甘菊环、己内酰胺,己酸、辛酸、4-甲基辛酸和癸酸在贮存6个月之后含量有明显增加趋势。在整个贮存期间,对羊奶粉膻味有较大影响的酸类物质有己酸、辛酸、4-甲基辛酸和癸酸,尤其是4-甲基辛酸,由于其较低阈值,成为最主要的羊膳物质,并且随着贮存时间的增加,酸类、酯类含量逐渐增加。展开更多
Aroma is an important component for characteristic of wine. β-glucosidase is an enzyme for enhancing wine aroma during fermentation and aging. The aim of this study was to evaluate β-glucosidase activities from 17 y...Aroma is an important component for characteristic of wine. β-glucosidase is an enzyme for enhancing wine aroma during fermentation and aging. The aim of this study was to evaluate β-glucosidase activities from 17 yeast strains. It was found that strain 71 B-1122 exhibited highest activity of β-glucosidase. The purified enzyme of this strain was characterized. The purified enzyme was added in Muscat must before wine making process. The must and wine were determined for volatile compounds by headspace-SPME/GC-MS and found that the hexyl acetate, linalool, phenethyl, nerol and geraniol compounds were significantly increased after treated with the enzyme. Sensory evaluation of the combined alcoholic fermentation and flavour enrichment of Muscat juice by adding of purified β-glucosidase enzyme showed well oenological properties especially aroma. Therefore, in producing wine, yeast strain selection and addition of β-glucosidase enzyme should be considered because they were important factors affecting wine aroma.展开更多
46 Streptococcus thermophilus strains,isolated from commercial starters cultures,were studied.The aroma of the fermented milk by these strains was evaluated by quantitative descriptive analysis(QDA).According to its m...46 Streptococcus thermophilus strains,isolated from commercial starters cultures,were studied.The aroma of the fermented milk by these strains was evaluated by quantitative descriptive analysis(QDA).According to its major sensory attribute,the fermented milks were classified into milky-type,creamy-type,cheesy-type,fermented-type and miscellaneous-type groups.One representative sample of each group was analyzed by headspace-gas chromatography-ion mobility spectrometry(HS-GC-IMS)and headspace-solid phase microextraction-gas chromatography-time-of-flight mass spectrometry(HS-SPME-GC-TOF/MS)to describe their volatile compositions.48 and 72 volatile compounds were identified,respectively.The fingerprint analysis showed that each aroma type had specific volatile compounds.Six important differential volatile compounds including 2,3-butanedione,2,3-pentanedione,2-undecanone,octanoic acid,hexanoic acid and 2-hydroxy-3-pentanone were selected as key compounds by principal component analysis(PCA)and orthogonal partial least squares discriminant analysis(OPLS-DA),which allowed to discriminate the specific aroma types.These key compounds could be used as indicators to develop fermented milks with specific aroma and flavor features.展开更多
文摘采用顶空固相微萃取结合气质联用(headspace-solid phase microextraction coupled with gas chromatography-mass spectrometry,SPME-GC/MS)技术,对常温贮存下羊奶粉中挥发性成分进行提取与分析。在常温贮存1年的羊奶粉中,共检出41种挥发性成分。其中酸类成分最多,共13种,其次是酯类、烃类、醇类和醛酮类,分别为6、4、4和3种。羊奶粉的主体挥发性成分组成是丁酸、己酸、庚酸、辛酸、4-甲基辛酸、癸酸、月桂酸、邻苯二甲酸二甲酯、辛酸乙酯、十五烷、苯甲醛、甘菊环、己内酰胺,己酸、辛酸、4-甲基辛酸和癸酸在贮存6个月之后含量有明显增加趋势。在整个贮存期间,对羊奶粉膻味有较大影响的酸类物质有己酸、辛酸、4-甲基辛酸和癸酸,尤其是4-甲基辛酸,由于其较低阈值,成为最主要的羊膳物质,并且随着贮存时间的增加,酸类、酯类含量逐渐增加。
文摘Aroma is an important component for characteristic of wine. β-glucosidase is an enzyme for enhancing wine aroma during fermentation and aging. The aim of this study was to evaluate β-glucosidase activities from 17 yeast strains. It was found that strain 71 B-1122 exhibited highest activity of β-glucosidase. The purified enzyme of this strain was characterized. The purified enzyme was added in Muscat must before wine making process. The must and wine were determined for volatile compounds by headspace-SPME/GC-MS and found that the hexyl acetate, linalool, phenethyl, nerol and geraniol compounds were significantly increased after treated with the enzyme. Sensory evaluation of the combined alcoholic fermentation and flavour enrichment of Muscat juice by adding of purified β-glucosidase enzyme showed well oenological properties especially aroma. Therefore, in producing wine, yeast strain selection and addition of β-glucosidase enzyme should be considered because they were important factors affecting wine aroma.
基金supported by National Natural Science Foundation of China(31972051,31771987)Key Program of Natural Science Foundation of Shandong Province in China(No.ZR2020KC009).
文摘46 Streptococcus thermophilus strains,isolated from commercial starters cultures,were studied.The aroma of the fermented milk by these strains was evaluated by quantitative descriptive analysis(QDA).According to its major sensory attribute,the fermented milks were classified into milky-type,creamy-type,cheesy-type,fermented-type and miscellaneous-type groups.One representative sample of each group was analyzed by headspace-gas chromatography-ion mobility spectrometry(HS-GC-IMS)and headspace-solid phase microextraction-gas chromatography-time-of-flight mass spectrometry(HS-SPME-GC-TOF/MS)to describe their volatile compositions.48 and 72 volatile compounds were identified,respectively.The fingerprint analysis showed that each aroma type had specific volatile compounds.Six important differential volatile compounds including 2,3-butanedione,2,3-pentanedione,2-undecanone,octanoic acid,hexanoic acid and 2-hydroxy-3-pentanone were selected as key compounds by principal component analysis(PCA)and orthogonal partial least squares discriminant analysis(OPLS-DA),which allowed to discriminate the specific aroma types.These key compounds could be used as indicators to develop fermented milks with specific aroma and flavor features.
