The structure of isoflavone moiety in soybean could be altered by thermal treatment. Thus, this study analyzed the isoflavone profiles of raw soybean extract (RSe, no pretreatment), blanched soybean extract (BSe, at 85oC for 3 min), and cooked soybean extract (CSe, at 95oC for 30 min) and measured their α-glucosidase inhibitory activities. The content of malonylglucosides in RSe decreased considerably during their transformation into BSe and CSe. The total content of isoflavones in RSe and BSe was fairly similar, although there was a significant difference in the respective values for RSe and CSe. It was concluded that the cooking treatment significantly impacted soybean isoflavone content and, eventually, one-quarter of isoflavones were lost in CSe. According to authentic isoflavone tests, the inhibition of α-glucosidase by isoflavone aglycones was more effective than that of the corresponding isoflavone glucosides. The α-glucosidase inhibitions were observed in the order of BSe (70.0%), CSe (53.3%), and RSe (32.3%). However, it was challenging to identify which isoflavone derivative had contributed to the phenomenon mentioned above. Hence, the blanching of soybean seemed to be more appropriate than cooking for preparing soybean extract to inhibit α-glucosidase due to the higher loss of isoflavone during cooking.

This study investigated the effect of bactocease, as a natural preservative, on the microbial growth and quality of fried fish paste during storage. To select the optimal concentration of bactocease, the inhibition effect of its different treatment concentrations (0.2, 0.4, and 0.8%) on total aerobic bacteria in fish paste dough during 5 days of storage was examined. The sample treated with 0.4% bactocease showed a 1.21 log reduction in microorganisms compared with that of the control. This result was higher than that with 0.2% bactocease and potassium sorbate and similar to that with 0.8% bactocease. Consequently, 0.4% bactocease was chosen as the best concentration for preparing the fried fish paste. Microbial growth on fried samples treated with preservatives was more inhibited by adding preservatives regardless of their type than that of the control after 15 days of storage. In addition, there were no significant differences in the quality between the samples treated with 0.4% bactocease and 0.2% potassium sorbate, such as volatile basic nitrogen contents, TBARS values, pH, and acidity. Therefore, these results indicate that food preservatives should be added into fried fish paste for controlling microbial growth, and bactocease can have a high potential to replace potassium sorbate in processed marine foods, including fried fish paste.

The salinity of the brining solution for preparing kimchi imparts saltiness to kimchi, and affects its overall taste. In this study, the changes in the overall taste and quality of kimchi depending on the salinity of the brining solution (6% and 12%) were investigated. The salinity of kimchi brined in 6% NaCl solution was approximately 1.3%, and its umami (2.22±0.22) was lower than that (2.96±0.16) of the conventional kimchi, brined in 12% NaCl solution. In contrast, its bitterness (-3.77±0.05) was higher than that of the conventional kimchi (-4.48±0.12). The sensory evaluation results showed that the overall taste score of the low-salinity kimchi (2.8±0.4) was significantly lower than that of the conventional kimchi (4.5±1.1). To overcome the deterioration in the overall taste, a taste enhancer with a sea tangle extract and anchovy extract was added to the low-salinity kimchi. The overall taste score (4.4±1.2) of the seasoned kimchi, which is the low-salinity kimchi supplemented with the taste enhancer, was comparable to that (4.5±1.1) of the conventional kimchi, while maintaining a salinity of 1.7%. This study demonstrated the benefits of proper taste enhancer for improving the taste of low-salinity kimchi.

The preparation of commercial, low-salinity kimchi needs to be carefully monitored to maintain the taste of kimchi. To address this, the taste profiles of three brands of commercial kimchi were examined using a taste sensing system, as well as a sensory evaluation. The average sensory score (4.3/9.0) in the overall taste of low-salinity kimchi (A', B', and C') was significantly lower than that (5.1/9.0) of conventional kimchi (A, B, and C). The explanation for the result of A' seemed to be its decrease in saltiness (3.51) and increase in bitterness (8.55) compared to those (6.55 and 7.65, respectively) of A. In B', the saltiness (4.25) and the overall taste (3.7) were significantly decreased compared to B (6.23 and 4.8, respectively). Interestingly, no significant difference was observed in the overall taste (5.1) and saltiness (6.70) of C' when compared to C (5.3 and 6.46, respectively), confirming that salinity is a crucial factor in determining overall taste. Consistent with this finding, the overall taste of low-salinity kimchi correlated positively with its saltiness (>0.98) and umami (>0.82). These results advocate the careful determination of salinity required to maintain the taste of conventional kimchi in preparing low-salinity kimchi, while also pointing towards the need to develop effective taste enhancers for supplementing overall taste.

Mulberry leaves have been used in oriental medicine for their anti-pyretic and anti-inflammatory benefits. However, their bitter taste and characteristic odor limit their use in food. Thus, mulberry leaves were fermented using three species of lactic acid bacteria prevalent in kimchi. MLp, MLm, and MLs were obtained by means of fermenting mulberry leaves, using Lactobacillus plantarum, Leuconostoc mesenteroides, and Lactobacilllus sakei. Their palatability and biochemical properties were measured to determine the feasibility of using each as a food ingredient. Overall acceptability of yoghurt supplemented with fermented mulberry leaves (MLp, MLm, or MLs) was greater than that for yoghurt supplemented with dried mulberry leaves, while fermentation produced no negative effect on yoghurt palatability. In addition, the total polyphenol levels and radical scavenging effects of mulberry leaf extracts increased with fermentation, but total flavonoid content was not significantly changed. One potentially detrimental effect of fermentation is that α- glucosidase inhibitory potency was slightly decreased, proportional to the decrease in the active component 1-deoxynojirimycin. Despite this minor loss, the improved flavor of fermented mulberry leaves, together with its other beneficial health effects, is expected to render them useful as a food ingredient without lowering the sensory appeal of their target foods.

Recently, polycosanol products have been actively introduced into the domestic market based on their potential biological activity. The analytical procedures of polycosanol, which determine the TMS derivatives of each polycosanol with GC-FID, were presented for inspection of standards. However, the conventional procedures are not readily applicable to polycosanol emulsion which is prepared by mixing polycosanol and water together with emulsifiers because of their interferences. Therefore, the quantitative analytical procedure of polycosanol emulsion with GC-MS at selected ion monitoring mode was proposed and its validity was inspected for standardization. The analysis of polycosanol standards according to the proposed procedure showed the following values: 90.5% for reproducibility; 0.48-5.83% for the RSD; 0.000479-0.001314 μg/μL for the LOD; 0.001452-0.003983 μg/μL for the LOQ; 80.38-108.98% for accuracy; and 0.01-4.88% for the coefficients of variation. The average reproducibilities of polycosanol emulsions according to the current procedure were 87.43±4.48% and 88±2.2%, respectively, which were within the 80-120% range of the designated amounts. Therefore, it was found that the proposed analytical procedure with GC-MS at SIM mode in this study would be promising for the accurate quantitative analysis of polycosanol emulsion.

Quality changes of retort pouched curry sauces were studied under various sterilization and storage conditions. The retort pouched curry sauces sterilized at 110oC for 30 min and stored at 37oC showed the lowest sensory qualities among the tested samples. Meanwhile, when the sample was sterilized at 101oC for 60 min and stored at 4oC, the quality changes of the sauces were not significant during 30 days of storage. The taste sensing results of curry sauces showed that there were not a lot of changes in flavor when stored at 4oC while the sauces stored at 37oC showed increases in bitterness and sourness which eventually caused degradation of total quality. Sensory evaluation results of the samples stored at 4oC (4.3 points) and at 37oC (3.5 points) also coincided with the taste sensing results. Conclusively, it is desirable to sterilize the retort pouched curry sauce at 101oC for 60 min and to store at 4oC until consumption (if possible, within 30 days). Further, the acid value (1.01) and pH (3.88) of curry sauces were found to be used as quality change indices for references.

Consumption of angelica leaves (Angelica utilis) juice as a health-improving drink faces some limitation due to its bitter taste. In this study, fermented angelica leaves was prepared using some lactic acid bacteria from kimchi with their sensory properties and biological activities examined. The addition of ALm (angelica leaves fermented by Leuconostoc mesenteroides) in plain yoghurt increased umami and preference compared to the yoghurt where dried angelica leaves were added. The ALm extract showed higher DPPH radical scavenging activity than other extracts and its flavonoid content was the highest. In case of A549 (lung cancer cell line) in CCK-8 assay, ALp (angelica fermented by Lactobacillus plantarum) extract exhibited inhibiting activity at 400 ppm level. When it comes to HT29 (colorectal cancer cell line), ALm, as well as Alp, depicted inhibition effects. In the fermented angelica leaves including ALm and ALp, the characteristic bitter taste of angelica leaves decreased through fermentation process so that both of them could be used as a health drink ingredient.

Many traditional fermented foods contain diverse bacteria and many lactic acid bacteria (LAB) play important roles for the fermentation of foods such as many dairy foods and kimchi. Especially, Leuconostoc mesenteroides is one of major bacteria in those fermented foods and the development of this species would be expected to be critical for strain improvement as well as the industrialization. Up to now, a lot of plasmids were isolated from Leuconostocs species including Leu. mesenteroides and a number of vector systems has been developed. Many plasmid vector systems using Leuconostocs spp. employ RCR (rolling circle replication) producing single-stranded DNA intermediates or sometimes takes theta replication. These plasmids include the sequences for Pre protein, recombination specific sites such as RSA (recombination site A) and RSB (recombination site B), and single strain origins for RCR replication. This information might be helpful to elucidate the improvement of Leuconostocs spp. and moreover the development of diverse products using Leuconostocs spp.

The taste properties of enzyme hydrolysates of rice protein residue were investigated, and then their taste enhancingeffects were evaluated by examining the changes in total taste pattern after their addition to a yeast extract. Whileenzyme hydrolysates of rice protein residue showed different taste properties according to the enzyme that was usedfor hydrolysis, the Flavourzyme treated sample expressed the strongest umami and bitter taste among the enzymetreated samples. On the other hand, the Protamax treated sample showed considerable umami with a slight bittertaste so that it is expected to be suitable as a taste enhancing ingredient. Furthermore, by LC-MS/MS analysis, theeffective fraction isolated from the Protamax treated sample was found to contain peptide fractions such as Ile-Gly-Tyr-Pro-Thr-Tyr-Pro-Leu-Pro-Arg (Mw: 1175); therefore, it is expected that the peptide fractions contained in Prot-amax hydrolysates of rice protein residue could be applied for preparing a natural taste enhancing ingredient.

Curcuma, which is well known for its characteristic flavor, was fermented with lactic acid bacteria from kimchi, andthe taste and biological activities were examined in order to investigate its use as a health food ingredient. Althoughthe general composition of the fermented curcuma was similar regardless of lactic acid bacteria used for fermenta-tion, the overall acceptability of the curcuma fermented with Lactobacillus plantarum (CLp) was better than that ofthe other samples. Taste sensing tests showed that the higher overall acceptability of CLp stemmed from an increasein umami and sourness and a decrease in astringency with CLp. There were no statistical differences in curcumincontent, DPPH radical scavenging activities, and hydroxyl radical scavenging activities among the curcuma samples;however, CLpe, an extract of CLp, revealed dose dependent inhibition on the production of PG-E2 from RAW cells.Consequently, CLpe may be suitable for use in processed foods in order to provide health benefits without loweringtheir sensory qualities.

생강은 다양한 생리활성이 확인됨에 따라 여러나라에서 전통의약재로서 폭넓게 사용되고 있다. 하지만 진저롤 및 그 유도체에서 유래되는 자극적인 향미로 인하여 식품소재로서의 사용에는 다소 어려움이 있는 실정이다. 본 연구에서는 생강을 Lactobacillus plantarum, Leuconostoc mesenteroides, Streptococcus thermophilus, 및 Lactobacillus acidophilus 등과 같은 유산균에 의한 발효를 통하여 생강의 관능특성을 증진시키려 하였다. 발효된 생강은 in vitro에서 전자공여능 및 cyclooxygenase-2 저해활성을 나타내었으며 또한 산화질소의 생성도 억제하였다. 특히 김치유래 유산균으로 발효한 생강추출물인 GLPe와 GLMe는 Raw 264.7 macrophages에서 prostaglandin-E2 의 생성을 60% 이상 저해하였으며 15-lipoxygenase에 대한 저해 활성도 나타내었다. 따라서 GLPe나 GLMe와 같은 발효생강 추출물은 섭취할 때 자극적인 향미로 인한 거부감이 적으며 염증이나 앨러지 등에 의해 야기되는 바람직하지 않은 증상을 일부 완화시킬 수 있는 건강식품소재로서 사용될 수 있음을 알 수 있었다.

마늘의 다양한 생리활성 기능은 잘 알려져 있음에도 불구하고 휘발성 황 화합물을 비롯한 마늘의 독특한 향과 맛으로 인해 가공식품 및 건강기능식품으로 활용하는데 있어 제한점이 많다. 따라서 본 연구에서는 대표적인 김치 발효균인 Lactobacillus plantarum KCTC 3104를 이용하여 마늘을 유산 발효시키고, 발효 마늘을 다시 적정 온도로 가열 처리함으로써 발효과정과 열처리가 마늘의 휘발성 황화합물과 항산화 활성에 어떠한 영향을 미치는지 평가하고자 하였다. 본 연구의 결과를 요약하자면 다음과 같다. (i)마늘에 존재하는 주요 휘발성 황 화합물인 allyl methyl sulfide 및 allyl sulfide, diallyl disulfide는 발효과정과 발효와 열처리 병행과정에서 감소하였으며 특히 열처리는 마늘의 자극적 향미성분을 감소시키는데 크게 기여하였다. (ii)무처리한 G와 발효를 한 FG, 그리고 발효와 열처리를 병행한 FG-H 간에 유의적인 peroxyl radical 소거활성은 차이는 없었다. (iii) 발효와 열처리를 병행한 FG-H는 마늘시료 G 에 비하여 hydroxyl raidcal 소거활성이 증가하였으며 이 증가된 hydroxyl radical 소거활성은 발효 및 열처리를 통해 새로이 생성된 물질에 의한 환원력 및 metal chelating 활성 증가에 기인된 것으로 추측된다. 이상의 연구결과는 발효 및 열처리를 통해 마늘의 자극적 향미를 개선할 수 있다는 가능성을 제시할 뿐만 아니라, 발효 및 열처리 마늘은 항산화 활성, 특히 hydroxyl radical 소거활성이 증가된 식품개발에 기초자료로 사용될 수 있을 것으로 생각된다.

본 연구는 probiotics 균주 선발을 위해 동치미로부터 식중독균에 대해 높은 항균활성을 보이는 유산균을 분리동정하여 배양조건을 확립하고, 위산, 담즙산, 췌장액에 대한 저항성 실험을 비교, 분석하여 probiotics 균주로 사용 가능성을 탐색하고자 하였다. 2% CaCO3를 첨가한 MRS agar를 이용하여 김치 무리로부터 식중독균의 저해능이 우수한 8 균주를 분리하였다. 식중독균에 대해 항균활성실험 결과 J4가 B. cereus는 19.85±0.53 mm, L. monocytogenes는 18.37±0.38 mm, S. aureus는 22.49±0.37 mm, E. coli는 17.90±0.64 mm, S. enterica는 16.28±0.53 mm, V. parahaemolyticus는 24.59±0.29 mm의 생육저해환을 형성하여 가장 높은 항균력을 나타내었다. J4 균주의 16S rDNA 염기서열을 분석한 결과 L. sakei와 99% 상동성을 나타내어 L. sakei J4라 명명하였다. L. sakei J4의 최적배양조건은 pH 8.5, 30, 정치배양시 가장 활발하게 생육이 진행됨을 확인하였다. L. sakei J4는 인공위액에서의 생존율 24.3±3.0%, 담즙산에서의 생존율 25.8±0.4%, 췌장액에서의 생존율 101.2±4.5%로 다른 균주보다 상대적으로 생존율이 높았으며, 향후 alginate를 이용한 캡슐화, chitosan을 이용한 재코팅 등의 연구방법을 정립하여 인공위액에 대한 저항성을 높인다면 프로바이오틱스 균주로서 조건을 충족시킬 수 있으리라 사료된다.

쌀단백질을 이용한 고부가가치 천연 조미소재를 개발하기 위하여 쌀단백질을 프로테아제로 효소분해한 배지에서 Saccharomyces cerevisiae를 배양하여 제조한 효모 추출물(Yx)에, 효소분해 후 남은 쌀단백질 잔사를 Bacillus licheniformis 혹은 Bacillus subtilis로 발효하여 얻은 발효물(Rfl, Rfs)을 각각 첨가하였다. 쌀단백질 잔사의 발효물이 첨가된 효모추출물(YxRfl, YxRfs)의 전체적 선호도는 첨가전의 효모추출물(Yx)에 비하여 높았으며, 특히 쌀단백질 발효물의 보충에 의해서 감칠맛과 같은 풍미가 증가함을 미각센서 분석 및 관능검사에 의해서 확인할 수 있었다. 쌀단백질 잔사발효물에 의한 감칠맛의 상승은 감칠맛을 내는 아미노산 이 외에도 쌀단백질의 발효에 따라 유리된 다양한 펩타이드 분획의 영향이 있었을 것으로 예상된다. 이와 같이 감칠맛 아미노산 및 펩타이드가 함유된 쌀단백질 발효물이 보충된 효모추출물은 감칠맛과 풍미의 상승작용으로 전체적인 기호도가 높아짐에 따라 고부가가치 천연조미소재의 제조에 응용될 수 있을 것으로 기대되었다.

쌀단백질을 효소분해하여 제조한 배양액으로 천연조미소재로 사용할 효모추출물을 제조하기 위한 최적 공정조건을 조사하였다. 쌀단백질(5%, w/w)을 단백분해효소인 Delvolase®로 효소분해한 상등분획에 3%(w/w) 수준으로 포도당을 첨가한 배지 조건이 가장 적절하였으며 이 조건에서 2.3 g/L의 효모를 회수하였다. 회수한 효모에는 RNA가 188.1 mg/g수준으로 함유되어 있었으며 GMP 및 IMP는 각각 650.33±48 μg/g, 69±21 μg/g 함유되어 있었다. 이와 같은 효모추출물에 효모배양액의 제조 후 남은 쌀단백질 잔사의 효소분해물(Rrh)을 혼합하면 감칠맛이 상승하였는데 미각센서 분석기로 측정한 결과 효모추출물의 감칠맛이 4.88에서 Rrh의 첨가 후에는 9.25로 증가하였으며 관능검사에서도 감칠맛의 증가를 확인할 수 있었다. 이와 같이 효모추출물에 쌀단백질 잔사의 효소분해물이 추가되면 효소분해 과정 중 생성된 다양한 맛 성분으로 인해 감칠맛이 상승되어 전체적인 기호도가 높아지므로 천연조미소재로서의 활용이 가능함을 알 수 있었다.