• Korean Journal of Food Science and Technology
• /
• v.17 no.5
• /
• pp.406-408
• /
• 1985

n-Hexanal in headspace over the cooked brown rice stored at $5^{\circ}C$ and $35^{\circ}C$ for 0. 4, 8 and 12 months was determined by a modified direct vapor injection gas chromatographic method. The retention time of n-hexanal was 3.5 min and n-hexanal could be rapidly separated from other compounds at the operational conditions of gas chromatography. n-Hexanal contents of cooked brown rice also showed a standard deviation of less than 10% of the average.

• Korean Journal of Food Science and Technology
• /
• v.29 no.6
• /
• pp.1319-1321
• /
• 1997

The effect of cooking peanut kernels before grinding on the hexanal content of peanut milk was investigated. Hexanal which is thought to be one of the major compounds contributing to the beany flavor of peanut milk, was quantified using a simplified headspace gas chromatographic method. Four cooking times (0, 10, 20 and 30 min) were evaluated. The concentration of hexanal in peanut milk was one-third by cooking peanut kernels for 10 min or longer. Protein content of peanut milk gradually decreased by heat treatments.

• Korean Journal of Food Science and Technology
• /
• v.39 no.1
• /
• pp.1-6
• /
• 2007

The effectiveness of cyclodextrin(CD) on binding and/or entrapping hexanal in model solution was investigated. The types and concentration of CDs for entrapping hexanal were studied using electronic nose, which composed of metal oxide sensor or was based on GC with surface acoustic wave sensor. ${\alpha}-CD$ was the most effective for lowering headspace concentration of hexanal in model solution. As concentration of CD increased, hexanal concentration in the headspace decreased significantly. Addition of 5% ${\beta}-CD$ to hexanal in model system resulted in 86% reduction of hexanal in the headspace. There was no difference between control and treatment at the initial stage of binding CD with hexanal while reduction of hexanal in the headspace was found during storage time. This could be estimated by electronic nose.

• Korean Journal of Food Science and Technology
• /
• v.13 no.1
• /
• pp.53-56
• /
• 1981

Several tests were conducted to study lipoxygenase activity and off-flavor developement in frozen sweet corn. Fresh corn contained about 60% of total lipoxygenase activity in the germ section. When non-blanched frozen sweet corn was stored at $-10^{\circ}F$, it developed off-flavor and most significant changes in the flavor profile of off-flavored sweet corn was $4{\sim}5$ times higher hexanal peaks. The high hexanal peaks observed in the sterilized sweet corn with added lipoxygenase, alone and in combination with other enzymes, suggested the fact that high hexanal peaks in off-flavored sweet corn could be due to an oxidative reaction of lionleic acid (and other unsaturated fatty acids) catalyzed by lipoxygenase. Based on lipoxygenase activity and linoleic acid content in sweet corn, this reaction occur most heavily in the germ section of sweet corn. There was a significant relationship between flavor score of frozen stored corn-on-the-cob and hexanal peak in the germ section of corn-on-the-cob. This result indicated that hexanal peak could be used as an objective index of off-flavor development in frozen sweet corn.

• The Korean Journal of Food And Nutrition
• /
• v.26 no.1
• /
• pp.146-149
• /
• 2013

This study was performed to identify the effect of lactic-fermentation of peanut milk on n-hexanal content. Changes in viable cell populations, pH and titratable acidity indicated that there was a synergistic interaction between Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus during fermentation. The analysis of headspace volatiles revealed that n-hexanal nearly disappeared due to fermentation. S. salivarius subsp. thermophilus was more effective than L. delbrueckii subsp. bulgaricus in reducing the n-hexanal content.

• Preventive Nutrition and Food Science
• /
• v.6 no.3
• /
• pp.197-199
• /
• 2001

The effects of cooking peanut kernels before grinding on the n-hexanal content of peanut milk was investigated. Analysis of headspace volatiles revealed that n-hexanal was greatly reduced by cooking peanut kernels before grinding. Total solids and protein content tended to decrease as cooking time was increased. The most satisfactory condition of cooking peanut kernels for preparing peanut milk was 10 min.

• Applied Biological Chemistry
• /
• v.34 no.2
• /
• pp.149-153
• /
• 1991

Several commercial soybean oils were stored at $20^{\circ}C,\;40^{\circ}C$ and $60^{\circ}C$ with daily exposure of fluorescent light for 12 hours and evaluated their rancidity by headspace gas chromatographic analysis of pentanal and hexanal. The data of gas chromatographic analysis was compared with organoleptic flavor evaluation. For headspace gas chromatographic analysis, the volatile compounds were recovered by porous polymer trap and flushed into a fused silica capillary column at $250^{\circ}C$, The pentanal and hexanal separated were identified by gas chromatography and gas chromatography-mass spectrometric method. The results showed that the contents of pentanal and hexanal were linearly increased during storage for 100 days. A very simple linear relationship was found between organoleptic flavor scores and amounts of two volatile compounds with very high correlation coefficient. A similar linear relationship was also obtained for acid and peroxide value with sensory data. This results suggested the possible implication of pentanal and hexanal as an quality index for rancidity evaluation of soybean oil.

• The Plant Pathology Journal
• /
• v.36 no.2
• /
• pp.133-147
• /
• 2020

Hexanal, a C-6 aldehyde has been implicated to have antimicrobial properties. Hence, this study was conducted to determine the antifungal activities of hexanal vapor against major postharvest pathogens of banana viz., Colletotrichum gloeosporioides and Lasiodiplodia theobromae. The pathogens were cultured in vitro and exposed to hexanal vapor at 600, 800, 1,000 and 1,200 ppm. Mycelial growth of both fungal pathogens were inhibited completely at 800 ppm and the incidence of anthracnose and stem-end rot diseases reduced by 75.2% and 80.2%, respectively. The activities of peroxidase, polyphenol oxidase, phenylalanine ammonia-lyase and glucanase had transiently increased in hexanal vapor treated banana by 5 to 7 days and declined thereafter. Postharvest treatment of banana with hexanal vapor resulted in phospholipase D inhibition and also resulted in cell wall thickening of the treated fruit, which impeded the penetration of the pathogenic spores. This was further confirmed by scanning electron micrographs. The defense-related protein intermediaries had increased in hexanal vapor treated banana fruit, which suggests induced resistance against C. gloeosporioides and L. theobromae, via., the phenylpropanoid pathway which plays a significant role in hindering the pathogen quiescence. Delayed ripening due to inhibition of phospholipase D enzyme, inhibition of mycelial growth and induced systemic resistance by defense enzymes collectively contributed to the postharvest disease reduction and extended shelf life of fruit.

• Korean Journal of Food Science and Technology
• /
• v.26 no.3
• /
• pp.331-335
• /
• 1994

The shelf-life of instant noodle stored at $35{\sim}65^{\circ}C$ under dark condition was estimated from the change of hexanal content, which was linearly increased as the storage time increased. The rate constants of hexanal production at various storage temperatures followed Arrhenius relationship. The activation energy and $Q_{10}$ calculated were 12.7 kcal/mole and 1.92, respectively. The rancid flavor was organoleptically detected after 6 days at $65^{\circ}C$ and 13 days $50^{\circ}C$, at which the content of hexanal was 3.5 ppm. The shelf-life of instant noddle at $21^{\circ}C$ based on $Q_{10}$ value of hexanal production was about 110 days. The changes of acid value and peroxide value of instant noodle during storage followed similar pattern to those of hexanal. The activation energy and $Q_{10}$ for both acid value and peroxide value were 16.0 kcal/mole and 2.55, respectively. The hexanal content showed a high positive correlation with acid value as well as peroxide value at all storage temperatures.

• The Korean Journal of Food And Nutrition
• /
• v.14 no.3
• /
• pp.199-203
• /
• 2001

땅콩유 제조시 땅콩의 침지시에 NaHCO$_3$를 첨가하는것과 분쇄전에 땅콩을 열처리하는 것이 n-hexanal 함량에 미치는 영향을 조사하기 위하여 headspace gas chromatgraphy 방법을 이용하여 조사하였다. 분쇄전에 땅콩을 열처리한 경우에는 n-hexanal함량이 현저하게 감소됨을 알 수 있었으며 열처리 시간이 증가함에 따라 n-hexanal 함량도 감소하지만 땅콩유중의 충고형분과 단백질함량도 함께 감소하였다. 이상의 결과로볼 때 콩비린내의 원인물질 중의 하나인 hexanal 함량의 감소를 위해서는 두유의 경우처럼 분쇄전에 땅콩을 열처리하는 것은 필수적이지만 지나친 열처리는 땅콩유는 단백질함량을 감소시켜 영양가가 저하시키므로 땅콩을 10분간 가열하는 것이 가장 바람직한 가공조건이라고 판단된다.