Determination of Volatile Flavor Compounds during Storage of Cereal Added Yogurt using HS-SPME

Abstract

In this study, quantitative analysis of major volatile flavor compounds from yogurt was conducted using headspace-solid phase microextraction (HS-SPME) GC-FID analysis technique, and the changes of volatile aroma compounds during the storage period were evaluated. The yogurt was prepared with the addition of 2% cereals, such as, white rice (WR), brown rice (BR), germinated brown rice (GBR) and saccharified germinated brown rice (SGBR). After fermentation, the products were stored at 5 o C for 15 d. The major volatile aroma compounds in yogurt, such as acetaldehyde, acetone, diacetyl and acetoin were able to be extracted using HS-SPME technique efficiently. The regression (r 2 ) value of standard curve prepared with various concentrations of individual flavor chemicals was analyzed over 0.9975, and reproducibility was acceptable to apply quantitative analysis. The analysis of volatile components of control sample during storage showed that the acetaldehyde on 0 d was 10.83 ppm, and that contents were increased to 15.67 ppm after 15 d of storage. However, addition of BR, GBR and SGBR decreased the acetaldehyde contents during storage periods. The acetone content of all treatments during storage was not significantly different. The diacetyl content of all treatments were increased during storage and the addition of SGBR showed the highest amount of diacetyl (0.84 ppm) among treatments on 15 d of storage. The acetoin content of yogurt added with grains was higher than that of control during storage. As a result, the content of volatile aroma compounds in yoghurt during storage period could be analyzed HS-SPME extraction technique effectively, and HS-SPME/GC analysis can be considered for quality control of fermented milk products. (Frank and Marth, 1988;Marshall, 1984;Rasic and Kurmann, 1978). 이러한 부산물은 발효유의 독특한 향기에 기 여를 하게 되며, 일부는 주요한 향기성분으로써 역할을 하 고, 나머지 수많은 화합물들은 전체적인 발효유의 향기에 기여한다 (Frank and Marth, 1988). 발효 중 젖산균에 의해 생성되는 carbonyl 화합물의 대표적인 물질은 acetaldehyde, diacetyl, acetoin, acetone 및 2-butanone 등이 있으며 (Frank and Marth, 1988;Marshall, 1984;Rasic and Kurmann, 1978), acetaldehyde와 diacetyl, 그리고 acetoin이 발효유에 서 중요한 향기성분으로 알려져 있고, 이 중 acetaldehyde 함량이 향기에 미치는 영향이 가장 크다 (Rasic and Kurmann, 1978

Antioxidant activity and flavor compounds of hickory yogurt

“…[36][37][38] When its concentration is in the range of 23-41 mg/kg, the yogurt has the best flavor. [39] The furfural contents in the two yogurts were not significantly different (p > 0.05), whereas the benzaldehyde content in HMY was significantly lower than that of CMY (p < 0.05). No butyraldehyde was identified in CMY.…”

“…[40] Some studies suggested that only when the acetaldehyde content is low, butanedione is the main flavor of yogurt. [39] Butanedione is lactic acid bacteria by the use of lactose metabolism by EMP pathway, but also by the formation of aspartate metabolism. [40] In HMY, the content of 2-nonanone increased by 1.42% compared with CMY (p < 0.05), contents of 2-heptanone, 1-hydroxy-2-propanone, and acetone were not significantly different from those in CMY (p > 0.05), and contents of 2,3-pentanedione, 2,3-butanedione and 3-hydroxy-2-butanone were significantly lower than those in CMY (p < 0.05).…”