Mustard Leaf Kimchi Research Articles

Draft genome sequence of Lactiplantibacillus plantarum KCKM 0106, isolated from mustard leaf kimchi.

Lactiplantibacillus plantarum KCKM 0106, isolated from mustard leaf kimchi, demonstrates probiotic properties, such as acid tolerance and adhesion to intestinal epithelial cells. We present the draft genome sequence of L. plantarum KCKM 0106, comprising 3,328,662 bp and 44.4% GC content.

Effect of high hydrostatic pressure (HHP) and supercooling storage in leaf mustard (Brassica juncea L.) kimchi: Modelling of microbial activity and preservation of physicochemical properties

Kimchi products have a short shelf life due to continuous bacterial growth and fermentation. Herein, the microbiological and physicochemical properties of leaf mustard (Brassica juncea L.) kimchi were evaluated after high hydrostatic pressure (HHP) treatment (400 and 600 MPa for 5 min) and storage under supercooling (˗4.5 °C) or refrigeration (4 and 8 °C) conditions. Moreover, predictive models describing the growth kinetics of total lactic acid bacteria (TLAB) in leaf mustard kimchi were constructed. Treatment with 600 MPa reduced the total LAB and coliform counts in the samples before storage to 1.30 and > 1 log CFU/g, respectively. Supercooling storage prevented microbial growth for 30 days and allowed the maintenance of the titratable acidity, reducing sugar content, instrumental colour, total phenolic content, and antioxidant capacity of the samples. The Logistic and Gompertz models were relatively more acceptable to predict the growth behaviour of TLAB in leaf mustard kimchi treated/non-treated with 400 MPa during supercooled or refrigerated storage. Altogether, these findings suggest that HHP treatment combined with supercooling storage conditions that delay O2 and CO2 concentration changes in packaged kimchi's headspace could help maintain the initial microbiological and physicochemical qualities of leaf mustard kimchi.

피브린 Zymographic Gel에서 Bacillus amyloliquefaciens G-13으로부터 혈전용해효소의 생성에 영향을 미치는 물리화학적 요인들의 비교

Our previous research demonstrated the characteristics and fibrinolytic activities of NaCl- and capsaicin-resistant bacterium Bacillus amyloliquefaciens G-13, isolated from mustard leaf kimchi [1]. In this study, we extended the work to the comparison of various physicochemical factors (e.g., temperature, pH, NaCl, capsaicin, metal ions, and inhibitors) influencing the production of fibrinolytic enzyme by strain G-13. Initially, a time course of the fibrinolytic activity of strain G-13 was measured by the fibrin plate assay, and after 84 hours of incubation, the maximum fibrinolytic activity was about 3.42 times that of plasmin used as the standard. Through a fibrin zymographic assay, four bands (23, 34, 45, and 67 kDa) of fibrinolytic enzyme from strain G-13 were compared in fibrin zymographic gels. The strain could grow and produce the fibrinolytic enzyme in the presence of NaCl (1-10%) or capsaicin (0-300 ㎍/mL), respectively. The optimum pH and temperature for the enzymatic activity were 8 and 35℃. In the study of the effects of metal ions on fibrinolytic activity, K⁺, CaSUP2+/SUP, and MgSUP2+/SUP ions increased the activity and maintained it overall, but FeSUP3+/SUP, ZnSUP2+/SUP, BaSUP2+/SUP, and HgSUP2+/SUP ions rapidly decreased the activity of the fibrinolytic enzyme. The enzyme was completely inhibited by phenylmethanesulfonyl fluroide (PMSF), suggesting that it was a serine protease. These results provide important clues for understanding the characteristics of fibrinolytic bacteria by confirming the effects of B. amyloliquefaciens G-13 on various physicochemical factors influencing the production of fibrinolytic enzymes through fibrin zymography.

Enhancement of the Anti-Inflammatory Effect of Mustard Kimchi on RAW 264.7 Macrophages by the Lactobacillus plantarum Fermentation-Mediated Generation of Phenolic Compound Derivatives.

Mustard leaf kimchi contains numerous functional compounds that have various health benefits. However, the underlying mechanisms of their anti-inflammatory effects are unclear. In this study, changes in the mustard leaf kimchi phenolics profile after fermentation with or without Lactobacillus plantarum were determined using liquid chromatography–mass spectrometry/mass spectrometry (LC–MS/MS). To correlate changes in phenolic profiles with anti-inflammatory activities of the fermentation extracts, lipopolysaccharides (LPS)-stimulated RAW 264.7 cells were treated with the extracts. We identified 12 phenolic acids in mustard leaf kimchi fermented with L. plantarum. Caffeic acid, chlorogenic acid, epicatechin, and catechin substituted the metabolite abundance. Extracts of mustard leaf kimchi fermented by L. plantarum (MLKL) markedly inhibited nitric oxide production by decreasing interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS), and cyclooxygenase 2 (COX2) expression levels in LPS-treated RAW 264.7 cells. Thus, fermentation with L. plantarum potentially improves the anti-inflammatory activities of mustard leaf and mustard leaf fermented with this microorganism may serve as a proper diet for the treatment of inflammation.

갓김치에서 분리한 NaCl 및 캡사이신 내성 세균인 Bacillus amyloliquefaciens G-13의 혈전용해활성

갓김치에서 분리한 NaCl 및 캡사이신 내성 세균인 Bacillus amyloliquefaciens G-13의 혈전용해활성

Investigation of glucosinolates, and the antioxidant activity of Dolsan leaf mustard kimchi extract using HPLC and LC-PDA-MS/MS

Leaf mustard (Brassica juncea), the main ingredient of leaf mustard kimchi, has a variety of biologically active secondary metabolites such as glucosinolates (GSLs), flavonoids, and polyphenols. In this study, the changes in GSL content and antioxidant properties during the storage of Dolsan leaf mustard kimchi (DLMK) for 35 days were examined by separation and purification of DLMK extracts using high-performance liquid chromatography (HPLC) and preparative octadecylsilane-HPLC. The total GSL content and antioxidant activity of the DLMK extracts had significantly lower values on day 21 of storage (p <.05). GSLs were detected in a single extract of DLMK using liquid chromatography-tandem mass spectrometry. The GSLs detected throughout most of the storage period (sinigrin, gluconapin, and glucotropaeplin) were different from those detected on day 21 of storage (glucobrassicin and progoitrin), when the antioxidant activity was low. Thus, GSLs may contribute to the antioxidant activity of DLMK. Practical applications Dolsan leaf mustard kimchi (DLMK) is expected to have biological effects owing to the properties of its various ingredients, but the effects of fermentation and the overall composition of DLMK on physiological activity have not been determined. On the basis of this study, DLMK has high value as a natural antioxidant, but the antioxidant activity varies with fermentation time, which is lowest on day 21. Thus, these results can be used to establish appropriate preparation conditions for DLMK as a functional food.

Changes in the phenolic compounds and antioxidant activities of mustard leaf (Brassica juncea) kimchi extracts during different fermentation periods.

This study was conducted to investigate the changes in the total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activities of 80% methanol and water extracts from mustard leaf kimchi during different fermentation periods. The methanol extract exhibited higher TPC and TFC than the water extract. Both extracts from kimchi fermented for two months showed the highest antioxidant effects against the scavenging activities of 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radicals and 2,2-azino-bis diammonium salt (ABTS) radicals. Moreover, the methanol extract from kimchi fermented for two months showed the highest nitrite scavenging activity. The highest metal (Fe2+) chelating effect of the methanol extract and water extract was observed after three months and one month, respectively. Caffeic acid showed the highest increase with fermentation. These findings suggest that the antioxidant activities of kimchi depend on the fermentation period. Accordingly, this study provides basic data for improving the antioxidant activity of mustard leaf kimchi through the establishment of their fermentation period.

갓김치(Brassica juncea) 숙성 중 영양성분 및 이화학적 특성 변화

Nutritional composition and physicochemical properties changes in mustard leaf kimchi were investigated during fermentation of up to 3 months. The pH decreased, and the titratable acidity gradually increased according to increase of fermentation periods. Fructose and glucose were the major free sugars in mustard leaf kimchi, and their amounts were significantly decreased with fermentation periods (p<0.05). Lactic acid content showed a significant increase with maximum increase at 3 months. All types of kimchi contained 20 amino acids, but the content of most amino acid fluctuated during fermentation. Except for K and Zn, the content of other ingredients including Ca, Fe, Mg, Na, Se were the highest in kimchi fermented for 2 months. The unsaturated fatty acid of mustard leaf kimchi was higher than that of saturated fatty acid, and total fatty acid of kimchi significantly decreased after 2 months (p<0.05). Most vitamin contents showed a tendency to decrease with fermentation, in particular, vitamin B complex except for <TEX>$B_2$</TEX> significantly decreased after 3 months (p<0.05). The results provide fundamental data for determining the appropriate fermentation period to improve the quality of kimchi.

돌산갓 김치와 돌산갓 피클의 Glucosinolates의 LC-PDA/MS/MS분석

Changes in the concentrations of glucosinolates and related compounds in different extracts of Dolsan leaf mustard kimchi (DLMK) and Dolsan leaf mustard pickles (DLMP) were during storage investigated. Samples were kept at 0℃ for 35 days and collected at 7 day intervals. The leaves and stems of DLMK and DLMP were refluxed for 24 h with 50% acetonitrile, and the extracts were analyzed by LC-PDA/MS/MS. The main glucosinolates detected in DLMK were sinigrin, gluconapoleiferin, glucobrassicanapin, and gluconapin, whereas those in DLMP were sinigrin, gluconapoleiferin, glucobrassicanapin, glucobrassicin, and glucoerucin. Sinigrin concentrations were quantified by UV absorption at 228 nm. Sinigrin concentrations in the leaves and stems of DLMK on the day of preparation were 2.14 mg/g and 2.25 mg/g, respectively, and those on day 35 after preparation were 1.25 mg/g and 1.00 mg/g, respectively. DLMP showed a similar trend: the concentrations in the leaves and stems on the day of preparation were 2.04 mg/g and 0.29 mg/g, respectively, whereas those on day 35 after preparation were 0.59 mg/g and 0.41 mg/g, respectively. Thus, sinigrin concentrations decreased during storage.

Factors Affecting Adhesion of Lactic Acid Bacteria to Caco-2 Cells and Inhibitory Effect on Infection of Salmonella Typhimurium

In this study, seven strains isolated from mustard leaf kimchi were screened for their tolerance to simulated gastric and bile juices, the adhesive properties to Caco-2 cells, and the inhibition ability of Salmonella Typhimurium ATCC 29631 adhesion. Lactobacillus acidophilus GK20, Lactobacillus paracasei GK74, and Lactobacillus plantarum GK81, which were resistant to bile as well as gastric juices, possessed high bile-salt hydrolase (BSH) activity towards both sodium glycocholate and sodium taurocholate. The strongest in vitro adherence of 53.96 +/- 4.49% was exhibited by L. plantarum GK81 followed by L. acidophilus GK20 with adhesion levels of 40.72 +/- 9.46%. The adhesion of these strains was significantly (p < 0.05) reduced after exposure to pepsin and heating for 30 min at 80 degrees C. Addition of Ca2+ led to a significant (p < 0.05) increase of the adhesion of L. acidophilus GK20, but the adhesion ability of L. plantarum GK81 was not different from the control by the addition of calcium. In the competition and exclusion experiment, the adhesion inhibition of S. Typhimurium by L. plantarum GK81 strain was much higher than the other strains. Moreover, the exclusion inhibition of S. Typhimurium by L. acidophilus GK20 was considerably high, although the inhibition activity of this strain was lower than L. plantarum GK81.

Synbiotic Potential of Yoghurt Manufactured with Probiotic Lactic Acid Bacteria Isolated from Mustard Leaf Kimchi and Prebiotic Fructooligosaccharide

In the present work, the influence of prebiotic fructooligosaccharide (FOS) on adhesion to Caco-2 cells, viability, acid and bile tolerance, antibacterial, antioxidant, enzymatic, and metabolic activities of the probiotic starters Lactobacillus acidophilus GK20 and Lactobacillus paracasei GK74, has been explored. Experiments were conducted with fermented yoghurt over a period of 7 days at . When compared to control fermentations without prebiotic, the addition of FOS was seen to significantly (p unit) and -galactosidase activities ( unit). However, FOS did not affect acid and bile tolerance, adhesion to Caco-2 cells or the antioxidant activity of the probiotics, although both L. acidophilus GK20 and L. paracasei GK74 had functionality as probiotic strains. Hence, a significant synbiotic effect was observed in fermented yoghurt after 7 days of storage at , and as a result, such synbiotic yoghurt can be said to possess synergistic actions which improve the gastrointestinal environment and promote of health.

Inhibitory effects of antagonistic compounds produced from Lactobacillus brevis MLK27 on adhesion of Listeria monocytogenes KCTC3569 to HT-29 cells

Among lactic acid bacteria (LAB) isolated from mustard leaf kimchi, MLK27 was the most efficient strain in terms of adhesion to HT-29 cells. Competitive, exclusive, and displaceable inhibition of Listeria monocytogenes KCTC 3569 adhesion by LAB was strain-dependent. MLK27 strain displayed the highest adhesion inhibition against L. monocytogenes and produced organic acids, hydrogen peroxide, and bacteriocin. Cell-free culture supernatants (100 μL/mL) and bacteriocin (1,280 AU/mL) of MLK27 strain strongly inhibited viable cell counts of L. monocytogenes adhered to HT-29 cells. However, there was no inhibitory effect of pathogen adhesion by bacteriocin treated with protease and inhibition activity of pathogen adhesion was partially decreased by heat-treated bacteriocin. According to biochemical and phylogenetic analysis, MLK27 strain was identified as Lactobacillus brevis MLK27. In conclusion, our results have shown that L. brevis MLK27 has ability to establish in human gastrointestinal tract and to prevent pathogenic L. monocytogenes infections, which is able to be considered as probiotic strains.

Synergy effects by combination with lactic acid bacteria and frutooligosaccharides on the cell growth and antimicrobial activity

The aim of this study was to identify probiotic possibility of lactic acid bacteria (LAB) from mustard leaf kimchi and investigate synergy effects of combination with LAB and fructooligosaccharide (FOS) on antimicrobial activity. Lactobacillus acidophilus GK20, L. paracasei GK74, and L. plantarum GK81 have high survival ratio under gastric and intestinal fluids and were resistant to ampicillin, streptomycin, or tetracycline. The pH of LAB gradually decreased but the titratable acidity increased owing to organic acids production. Especially, L. acidophilus GK20 and L. paracasei GK74 produced hydrogen peroxide and bacteriocin. When LAB was co-cultured with Listeria monocytogenes or Staphylococcus aureus in broth without FOS, the inhibition ratio of L. monocytogenes and S. aureus by L. acidophilus GK20 was 36 and 57%, but L. paracasei GK74 showed higher inhibitory effect against L. monocytogenes than S. aureus. Meanwhile, the cell growth, culture pH, titratable acidity, and bacteriocin activity of L. acidophilus GK20 and L. paracasei GK74 were significantly (p<0.05) increased in MRS with FOS than without prebiotic. In conclusion, L. acidophilus GK20 and L. paracasei GK74 could be potentially used as novel probiotic strains, moreover, the combination between L. acidophilus GK20 or L. paracasei GK74 and FOS has great potential as a synbiotic.

절임조건에 따른 돌산갓의 이화학적 특성 변화

돌산갓의 최적 절임조건을 조사하기 위하여 다양한 절임시간, 수세방법, 저장온도에 따른 돌산갓의 물리화학적 특성을 비교하였다. 또한, 최적조건에서 절임된 돌산갓을 50일 동안 저장하는 동안 유산균의 균수변화를 측정하였다. 절임돌산갓의 관능평가와 아삭거림의 결과로부터 장기간 보존을 위한 최적조건은 8시간 절임 후 염농도를 단계적으로 수세한 방법으로 나타났다. 절임돌산갓은 <TEX>$4^{\circ}C$</TEX>에서 저장되는 동안 유산균의 증가에 의해 pH가 감소하였다. 저장기간 동안 절단력은 천천히 증가하였으나, 염농도를 단계적으로 수세하였을 때는 절단력이 초기값과 비슷하게 유지되었다. 40일 저장된 절임돌산갓의 색변화는 관찰되지 않았으나 50일이 지나면서 갈변현상이 나타나 김치제조는 불가능 할 것으로 판단된다. 이들 결과들은 김치제조를 위한 절임돌산갓의 최적 절임조건과 저장기간으로 응용될 수 있을 것이다. To investigate the optimal salting conditions, the physicochemical properties of Dolsan leaf mustard were compared under various salting times and using various washing methods and storage temperatures at 10% saline. On the other hand, the cell number of lactic-acid bacteria in Dolsan leaf mustard salted under the optimal conditions was also examined during the 50-day storage. The results of the sensory evaluation of the crispness value of the Dolsan leaf mustard treated with stepwise washing after 8h salting showed the optimal conditions for long-term preservation. The pH of the salted Dolsan leaf mustard decreased with the increase in the lactic-acid bacteria during the storage at <TEX>$4^{\circ}C$</TEX>. The cutting energy slowly increased during the storage, but the cutting energy of the salted Dolsan leaf mustard treated with stepwise washing remained at the initial values. The color of the salted Dolsan leaf mustard did not change during 40-day storage, but the mustard turned brown after 50-day storage, for which reason it could not be made into Dolsan leaf mustard kimchi. These results could be recommended as the optimal salting conditions and storage time of salted Dolsan leaf mustard for making kimchi.

The antioxidative properties of mustard leaf (Brassica juncea) kimchi extracts on refrigerated raw ground pork meat against lipid oxidation

The efficacy of varying concentration of mustard leaf kimchi ethanolic extracts (MK) in retarding oxidative rancidity was tested with raw ground pork. Freshly ground pork meat was assigned to one of the following five treatments: control (no antioxidants); AC-0.02 (0.02% ascorbic acid); MK-0.05, 0.1, and 0.2 (0.05%, 0.1% and 0.2% MK, respectively). The pH of the samples decreased and the TBARS values and free fatty acids (%) increased considerably (P<0.05) during storage. The total bacterial count was lower in MK-0.1 and MK-0.2 than the control during storage. The internal L* value and a* value decreased (P<0.05) with the addition of MK. The internal b* value of MK treatments were higher (P<0.05) than that for the control and increased incrementally with MK concentration. The TBARS values and free fatty acids (%) of MK-0.02 was lowest among the treatments. The peroxide value of the control increased until 7 days and reached the maximum value at a certain storage time and decreased thereafter. In the other treatments it increased. All treatments had lower concentration of conjugated dienes (P<0.05) compared to the control sample, after the first day. Mustard leaf kimchi ethanolic extracts exhibited a protective effect against lipid oxidation in raw ground pork.

Cytotoxicity of extracts from Dolsan leaf mustard Kimchi treated with lactic acid bacteria on lung and gastric cancer cells

The cytotoxicity of extracts from Dolsan leaf mustard Kimchi (DLMK) treated with lactic acid bacteria on A 549 human lung cancer cells and SNU-601 human gastric cancer cells were investigated. Leuconostoc mesenteroides, Leu. Gelidum, and Weissella kimchii previously isolated from properly ripened DLMK were inoculated to DLMK as a starter (1 × 108 CFU/mL). The DLMK was then fractionated by various extracting solvents. The cytotoxicity of MeOH extracts from DLMK on A 549 and SNU-601 cancer cells was found to occur in a dose-dependent manner. Although the cytotoxicity of the MeOH extracts was found to be approximately 20 to 30% at concentrations of 250 μg/mL by MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide) assay, cytotoxicity of chloroform soluble fraction of DLMK treated with W. kimchii showed about 80 to 90%. Consequently, the growth of cancer cells was inhibited significantly in medium containing DLMK extracts. In addition, significant morphological changes such as cell condensation, cell fragmentation, and alterations in the size and shape of the cells were observed in cells grown in medium that contained the DLMK extracts. Taken together, these results suggest that inhibition of the proliferation of cancer cells by apoptosis was induced by DLMK extracts.

Antimutagenic and Anticancer Effects of Leaf Mustard and Leaf Mustard Kimchi

In this study, we investigated antimutagenic and anticancer activities of leaf mustard (LM, Brassica juncea) and leaf mustard kimchi (LMK) during their fermentation period. Methanol extracts were prepared from raw mustard, brined leaf mustard in 10% Gueun salt solution for 2 hrs, leaf mustard fermented at 15℃ for 5 days after brined in 10% Guenun salt solution for 2 hrs (Fr-LM), fresh leaf mustard kimchi (Fresh-LMK) and optimally ripened leaf mustard kimchi fermented at 5℃ for 30 days (OR-LMK). OR-LMK showed the strongest inhibitory activities against the mutagenicities induced by aflatoxin B1 in Salmonella Typhimurium TA100. LMs and LMKs inhibited the survival or growth of AGS human gastric adenocarcinoma cells and HT-29 human colon carcinoma cells in MTT assay and growth inhibition test. Among the extracts, OR-LMK and FR-LM exhibited strong antiproliferative effect against cancer cells, especially HT-29 cells. DAPI staining assay showed that OR-LMK induced apoptosis cell death of HT-29 cells in a dose-dependent manner. These results suggest that leaf mustards and leaf mustard kimchi have chemopreventive activities.

Cytotoxic, antioxidative, and ACE inhibiting activities of dolsan leaf mustard juice (DLMJ) treated with lactic acid bacteria

This study was performed to know whether there is any change of physiological activity in DLMJ which is inoculated by lactic acid bacteria. Lactic acid bacteria were isolated from Dolsan leaf mustard Kimchi (DLMK) at 20°C. In the optimum ripening period, the population ofLeuconostoc andLactobacilli in the DLMK were found to be high. TheLeuconostoc, Lactobacilli andLactococci strains were identified asLeuconostoc mesenteroides., Leuconostoc gelidum, Weissella confusa, Lactobacillus plantarum, Lactobacillus raffinolactis, Lactococcus lactis andWeissella confusa using the Biolog system. The most predominant strain which was isolated from DLMK wasWeissella confusa. As the results of the phylogenetic analysis using 16s rDNA sequence, theWeissella confusa turned out to beWeissella kimchii, with 99.0% similarity. To investigated the change of physiological activity in DLMJ by lactic acid bacteria, 7 predominant strains inoculated to DLMJ (Dolsan Leaf Mustard Juice). The cytotoxicity was found to be under 19.55% all cases Also, the antioxidative activity of the DLMJ treated with lactic acid bacteria was very low, which might have been due to the reduced antioxidative phytochemicals during the preparation of the sterile, sample. The ACE inhibiting activity of DLMJ by inoculation withWeissella kimchii was shown to be the highest (94.0%). This could be that the degradation of sulfur containing materials in DLMJ byWeissella kimchii gave rise to ACE inhibiting activity.

클로로필의 광산화에 미치는 β-카로텐과 비타민 C의 영향

클로로필의 광산화에 미치는 β-카로텐과 비타민 C의 역할을 linoleic acid emulsion 모델 시스템과 피부조직 균질액을 이용하여 조사하고 이와 더불어 각각의 성분들의 조합시 일어나는 변화를 살펴보았다. Linoleic acid emulsion 모델 시스템에서 클로로필과 β-카로텐은 고농도에서 자외선 B에 의한 광산화를 촉진시키는 것으로 나타났으며 고농도의 비타민 C는 이를 억제시켰다. 갓김치에 함유되어 있는 클로로필, β-카로텐, 비타민 C 농도를 참고하여 이들을 조합하였을 때 자외선 B에 의한 광산화를 억제시켰으며 β-카로텐의 경우 단독으로 사용되었을 때에는 산화를 촉진하였으나 다른 항산화성분들과 함께 사용될 경우 항산화활성을 나타내었다. ICR mouse의 피부조직 균질액에 클로로필, β-카로텐, 비타민 C를 단독 또는 혼합하여 첨가하였을 때 클로로필 a, b 및 β-카로텐의 첨가는 광산화를 가속화시켰다. 비타민 C의 경우 50 ppm을 첨가하였을 때에는 아무런 효과를 나타내지 않았으나 500 ppm을 첨가하였을 때에는 자외선 B에 의한 광산화를 효과적으로 억제시켰다. 500 ppm의 비타민 C에 클로로필과 β-카로텐을 혼합하였을 때에도 광산화가 억제되었으며 비타민 C의 농도가 중요하게 작용하였다.

김치종류별 식이가 Hairless Mouse 피부의 형태학적 변화에 미치는 영향

피부는 외부의 물리적 화학적 자극으로부터 신체를 보호하는 중요한 역할을 하며 노화에 따른 조직의 형태학적인 변화를 쉽게 관찰할 수 있는 기관이다. 동결건조한 배추김치, 갓김치, 부추김치를 식이에 10%씩 첨가하여 hairless mouse에 16주간 섭취시켜 피부조직에 미치는 영향을 살펴보았다. 노화가 진행됨에 따라 표피의 두께는 감소하며 본 실험에서 대조군에 비해 김치섭취군에서 유의적으로 두꺼운 것으로 나타났다. 피부 각질화에 관여하는 cytokeratin은 대조군에 비해 갓, 배추, 부추김치군의 순으로 낮았는데 전자현미경적 소견으로도 대조군에서 각질층은 중간원섬유들이 치밀하게 분포된 매우 두꺼운 각질층이 보인 반면 갓김치, 배추김치, 부추김치군은 얇은 각질층으로 배열되어 있었다. 상피기저막의 type Ⅳ 콜라겐은 갓김치섭취군에서 현저하게 증가되어 갓김치 성분들이 피부의 기저막의 노화를 억제한 것으로 사료된다. 콜라겐 함량은 노화에 따라 감소하며 대조군에서 콜라겐의 합성에 관여하는 fibroblast의 RER 발달은 뚜렷하지 않았으나 갓김치군, 배추김치군에서는 RER의 발달이 현저하여 새로운 콜라겐 생성이 활발히 이루어지는 것으로 나타났다. 이러한 결과로 보아 많은 생리활성물질 및 항산화물질이 함유되어진 김치의 섭취는 피부노화를 방지할 수 있을것으로 기대되며 특히 갓김치의 효과가 우수한 것으로 나타났다.