Korea Food Research Institute

autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field.

Four different types of chitosan-based nanocomposite films were prepared using a solvent-casting method by incorporation with four types of nanoparticles, that is, an unmodified montmorillonite (Na-MMT), an organically modified montmorillonite (Cloisite 30B), a Nano-silver, and a Ag-zeolite (Ag-Ion). X-ray diffraction patterns of the nanocomposite films indicated that a certain degree of intercalation was formed in the nanocomposite films, with the highest intercalation in the Na-MMT-incorporated films followed by films with Cloisite 30B and Ag-Ion. Scanning electron micrographs showed that in all of the nanocomposite films, except the Nano-silver-incorporated one, nanoparticles were dispersed homogeneously throughout the chitosan polymer matrix. Consequently, mechanical and barrier properties of chitosan films were affected through intercalation of nanoparticles, that is, tensile strength increased by 7-16%, whereas water vapor permeability decreased by 25-30% depending on the nanoparticle material tested. In addition, chitosan-based nanocomposite films, especially silver-containing ones, showed a promising range of antimicrobial activity.

Fermented foods have unique functional properties imparting some health benefits to consumers due to presence of functional microorganisms, which possess probiotics properties, antimicrobial, antioxidant, peptide production, etc. Health benefits of some global fermented foods are synthesis of nutrients, prevention of cardiovascular disease, prevention of cancer, gastrointestinal disorders, allergic reactions, diabetes, among others. The present paper is aimed to review the information on some functional properties of the microorganisms associated with fermented foods and beverages, and their health-promoting benefits to consumers.

High fat diet-induced changes in gut microbiota have been linked to intestinal permeability and metabolic endotoxemia, which is related to metabolic disorders. However, the influence of a high-glucose (HGD) or high-fructose (HFrD) diet on gut microbiota is largely unknown. We performed changes of gut microbiota in HGD- or HFrD-fed C57BL/6J mice by 16S rRNA analysis. Gut microbiota-derived endotoxin-induced metabolic disorders were evaluated by glucose and insulin tolerance test, gut permeability, Western blot and histological analysis. We found that the HGD and HFrD groups had comparatively higher blood glucose and endotoxin levels, fat mass, dyslipidemia, and glucose intolerance without changes in bodyweight. The HGD- and HFrD-fed mice lost gut microbial diversity, characterized by a lower proportion of Bacteroidetes and a markedly increased proportion of Proteobacteria. Moreover, the HGD and HFrD groups had increased gut permeability due to alterations to the tight junction proteins caused by gut inflammation. Hepatic inflammation and lipid accumulation were also markedly increased in the HGD and HFrD groups. High levels of glucose or fructose in the diet regulate the gut microbiota and increase intestinal permeability, which precedes the development of metabolic endotoxemia, inflammation, and lipid accumulation, ultimately leading to hepatic steatosis and normal-weight obesity.

This review summarizes the current trends related to insect as food resources among consumers, industry, and academia. In Western societies, edible insects have a greater potential as animal feed than as human food because of cultural biases associated with harmful insects, although the abundant characteristics of edible insects should benefit human health. Nevertheless, many countries in Asia, Oceania, Africa, and Latin America utilize insects as a major protein source. Using insects can potentially solve problems related to the conventional food-supply chain, including global water, land, and energy deficits. Academic, industry, and government-led efforts have attempted to reduce negative perceptions of insects through developing palatable processing methods, as well as providing descriptions of health benefits and explaining the necessity of reducing reliance on other food sources. Our overview reveals that entomophagy is experiencing a steady increase worldwide, despite its unfamiliarity to the consumers influenced by Western eating habits.

This mini review focuses on foodborne illnesses and outbreaks caused by food-producing animals because statistical information of the foodborne illnesses is important in human health and food industry. Contaminated food results in 600 million cases of foodborne diseases and 420,000 deaths worldwide every year. The world population is currently 7.8 billion, and 56 million people die every year; of these, every year, 7.69% of people experience foodborne diseases, and 7.5% of annual deaths (56 million deaths) was died by foodborne illness in the world. A majority of such patients are affected by norovirus and Campylobacter. Listeria monocytogenes is the most fatal. In the United States, except for those caused by Campylobacter, the number of foodborne diseases did not decrease between 1997 and 2017, and cases caused by Toxoplasma gondii are still being reported (9 cases in 2017). The percentage of foodborne illnesses caused by food-producing animals was 10.4%–14.1% between 1999 and 2017 in the United States. In Europe, foodborne illnesses affect 23 million people every year and cause approximately 5,000 deaths. Europe has more Campylobacter- and Salmonella-related cases than in other countries. In Australia, the highest number of cases are due to Campylobacter, followed by Salmonella. In Korea, Escherichia coli followed by norovirus. Campylobacter- and Clostridium perfringens-related cases have been reported in Japan as well. This review suggests that Campylobacter, Salmonella, L. monocytogenes, and E. coli, which are usually isolated from animal-source food products are associated with a high risk of foodborne illnesses.

Liver and serum metabolites of obese and lean mice fed on high fat or normal diets were analyzed using ultraperformance liquid chromatography-quadrupole-time-of-flight mass spectrometry, gas chromatography-mass spectrometry, and partial least-squares-discriminant analysis (PLS-DA). Obese and lean groups were clearly discriminated from each other on PLS-DA score plot and major metabolites contributing to the discrimination were assigned as lipid metabolites (fatty acids, phosphatidylcholines (PCs), and lysophosphatidylcholines (lysoPCs)), lipid metabolism intermediates (betaine, carnitine, and acylcarnitines), amino acids, acidic compounds, monosaccharides, and serotonin. A high-fat diet increased lipid metabolites but decreased lipid metabolism intermediates and the NAD/NADH ratio, indicating that abnormal lipid and energy metabolism induced by a high-fat diet resulted in fat accumulation via decreased β-oxidation. In addition, this study revealed that the levels of many metabolites, including serotonin, betaine, pipecolic acid, and uric acid, were positively or negatively related to obesity-associated diseases. On the basis of these metabolites, we proposed a metabolic pathway related to high-fat diet-induced obesity. These metabolites can be used to better understand obesity and related diseases induced by a hyperlipidic diet. Furthermore, the level changes of these metabolites can be used to assess the risk of obesity and the therapeutic effect of obesity management.

Epidemiological studies suggest that a high consumption of fruits can reduce the risk of some cancers and cardiovascular disease, and this may be attributable to the antioxidant activity of vitamins and phenolic compounds. The present study investigated the variations in vitamin C, total phenolic, hesperidin, and naringin contents, and total antioxidant activity of yuzu (Citrus junos Sieb ex Tanaka)-which is a popular citrus fruit in Korea and Japan-between cultivars and during maturity. The amounts of phenolics and vitamin C and the antioxidant activity in all tested yuzu cultivars were higher in peel than in flesh. Ripening increased the total antioxidant activity and vitamin C content in both peel and flesh of yuzu. However, the amounts of all total phenolics, hesperidin, and naringin in peel increased with ripening, whereas they decreased slightly in flesh. There was a highly linear relationship between the vitamin C content and the total antioxidant activity in both peel (r(2) = 1.000) and flesh (r(2) =0.998), suggesting that vitamin C plays a key role in the antioxidant activity of yuzu. In addition, the contribution of each antioxidant to the total antioxidant activity of yuzu was determined using a 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging assay and is expressed here in terms of the vitamin C equivalent antioxidant capacity (VCEAC). The means of vitamin C, naringin, and hesperidin in yuzu were 90.4, 63.8, and 65.7 mg/100 g fresh yuzu, respectively. The relative VCEAC values of these compounds were in the following order: vitamin C (1.00) > naringin (0.195) > hesperidin (0.162). Therefore, the estimated contribution of each antioxidant to the total antioxidant capacity of 100 g of fresh yuzus is as follows (in mg of VCEAC): vitamin C (90.36 mg) > naringin (12.44 mg) > hesperidin (10.64 mg). Our results indicate that mature yuzu contains higher amounts of vitamin C and phenolics than other citrus fruits and could therefore be used as a significant dietary source of antioxidants.

ULK1 (unc-51 like autophagy activating kinase 1), the key mediator of MTORC1 signaling to autophagy, regulates early stages of autophagosome formation in response to starvation or MTORC1 inhibition. How ULK1 regulates the autophagy induction process remains elusive. Here, we identify that ATG13, a binding partner of ULK1, mediates interaction of ULK1 with the ATG14-containing PIK3C3/VPS34 complex, the key machinery for initiation of autophagosome formation. The interaction enables ULK1 to phosphorylate ATG14 in a manner dependent upon autophagy inducing conditions, such as nutrient starvation or MTORC1 inhibition. The ATG14 phosphorylation mimics nutrient deprivation through stimulating the kinase activity of the class III phosphatidylinositol 3-kinase (PtdIns3K) complex and facilitates phagophore and autophagosome formation. By monitoring the ATG14 phosphorylation, we determined that the ULK1 activity requires BECN1/Beclin 1 but not the phosphatidylethanolamine (PE)-conjugation machinery and the PIK3C3 kinase activity. Monitoring the phosphorylation also allowed us to identify that ATG9A is required to suppress the ULK1 activity under nutrient-enriched conditions. Furthermore, we determined that ATG14 phosphorylation depends on ULK1 and dietary conditions in vivo. These results define a key molecular event for the starvation-induced activation of the ATG14-containing PtdIns3K complex by ULK1, and demonstrate hierarchical relations between the ULK1 activation and other autophagy proteins involved in phagophore formation.

Abstract This review provides current information on the analytical methods used to identify food adulteration in the six most adulterated food categories: animal origin and seafood, oils and fats, beverages, spices and sweet foods (e.g. honey), grain‐based food, and others (organic food and dietary supplements). The analytical techniques (both conventional and emerging) used to identify adulteration in these six food categories involve sensory, physicochemical, DNA ‐based, chromatographic and spectroscopic methods, and have been combined with chemometrics, making these techniques more convenient and effective for the analysis of a broad variety of food products. Despite recent advances, the need remains for suitably sensitive and widely applicable methodologies that encompass all the various aspects of food adulteration. © 2017 Society of Chemical Industry

Plant-based meat analogues, edible insects, and cultured meat are promising major meat alternatives that can be used as protein sources in the future. It is also believed that the importance of meat alternatives will continue to increase because of concerns on limited sustainability of the traditional meat production system. The meat alternatives are expected to have different roles based on their different benefits and limitations. Plant-based meat analogues and edible insects can replace traditional meat as a good protein source from the perspective of nutritional value. Furthermore, plant-based meat can be made available to a wide range of consumers (e.g., as vegetarian or halal food products). However, despite ongoing technical developments, their palatability, including appearance, flavor, and texture, is still different from the consumers' standard established from livestock-based traditional meat. Meanwhile, cultured meat is the only method to produce actual animal muscle-based meat; therefore, the final product is more meat-like compared to other meat analogues. However, technical difficulties, especially in mass production and cost, remain before it can be commercialized. Nevertheless, these meat alternatives can be a part of our future protein sources while maintaining a complementary relationship with traditional meat.

To understand the molecular mechanisms underlying the influence of quercetin on the physiological effects of hyperlipidemia, we investigated its role in the prevention of high-fat diet (HFD)-induced obesity and found that it regulated hepatic gene expression related to lipid metabolism. Quercetin supplementation in mice significantly reduced the HFD-induced gains in body weight, liver weight, and white adipose tissue weight compared with the mice fed only with HFD. It also significantly reduced HFD-induced increases in serum lipids, including cholesterol, triglyceride, and thiobarbituric acid-reactive substance (TBARS). Consistent with the reduced liver weight and white adipose tissue weight, hepatic lipid accumulation and the size of lipid droplets in the epididymal fat pads were also reduced by quercetin supplementation. To further investigate how quercetin may reduce obesity, we analyzed lipid metabolism-related genes in the liver. Quercetin supplementation altered expression profiles of several lipid metabolism-related genes, including Fnta, Pon1, Pparg, Aldh1b1, Apoa4, Abcg5, Gpam, Acaca, Cd36, Fdft1, and Fasn, relative to those in HFD control mice. The expression patterns of these genes observed by quantitative reverse transcriptase-polymerase chain reaction were confirmed by immunoblot assays. Collectively, our results indicate that quercetin prevents HFD-induced obesity in C57B1/6 mice, and its anti-obesity effects may be related to the regulation of lipogenesis at the level of transcription.

Rice bran contains many phenolic acids, the most abundant of which is the antioxidant, ferulic acid (FA). We evaluated the hypoglycemic effects of a phenolic acid fraction (the ethyl acetate fraction, EAE) of rice bran and of FA in C57BL/KsJ db/db mice. Type 2 diabetic mice were allocated to a control group, an EAE group, or an FA group. Animals were fed a modified AIN-76 diet, and EAE or FA was administered orally for 17 days. There was no significant difference in body weight gain between groups. Administration of EAE and FA significantly decreased blood glucose levels and increased plasma insulin levels. EAE or FA groups had significantly elevated hepatic glycogen synthesis and glucokinase activity compared with the control group. Plasma total cholesterol and low density lipoprotein (LDL) cholesterol concentrations were significantly decreased by EAE and FA administration. These findings suggest that EAE and FA may be beneficial for treatment of type 2 diabetes because they regulate blood glucose levels by elevating glucokinase activity and production of glycogen in the liver.

SCOPE: Atherosclerosis is a major cause of cardiovascular disease caused by high cholesterol. Stains are widely prescribed to lower cholesterol levels, but natural dietary compounds may also be effective. Therefore, we studied the effect of the natural dietary compound curcumin on atherosclerosis and its underlying mechanisms based on plasma and hepatic lipid metabolism. METHODS AND RESULTS: LDLR(-/-) mice were fed a high-cholesterol diet and treated with curcumin, lovastatin or control (n=10 per group) for 18 wk. Aortic arch sections revealed curcumin ameliorated early atherosclerotic lesions, lipid infiltration, ICAM-1 and VCAM-1 localization, similar to lovastatin treatment. Furthermore, curcumin lowered plasma cholesterol, triglycerides, LDL cholesterol and Apo B levels as well as CETP activity, while curcumin increased plasma HDL cholesterol and liver Apo A-I expression, similar to lovastatin treatment. Curcumin caused transcriptional inhibition of HMG-CoA reductase, independent of ACAT1 and ACAT2 expression. Hepatic PPARα and LXRα expression was upregulated by curcumin treatment. Hepatic complement factor D (Cfd) and systemic CRP levels, markers of immune complement pathway activation, were significantly reduced by curcumin treatment. CONCLUSION: Long-term curcumin treatment lowers plasma and hepatic cholesterol and suppresses early atherosclerotic lesions comparable to the protective effects of lovastatin. The anti-atherogenic effect of curcumin is mediated via multiple mechanisms including altered lipid, cholesterol and immune gene expression.

Curcumin, a polyphenol found in the rhizomes of Curcuma longa, improves obesity-associated inflammation and diabetes in obese mice. Curcumin also suppresses adipocyte differentiation, although the underlying mechanism remains unclear. Here, we used 3T3-L1 cells to investigate the details of the mechanism underlying the anti-adipogenic effects of curcumin. Curcumin inhibited mitogen-activated protein kinase (MAPK) (ERK, JNK, and p38) phosphorylation that was associated with differentiation of 3T3-L1 cells into adipocytes. During differentiation, curcumin also restored nuclear translocation of the integral Wnt signaling component beta-catenin in a dose-dependent manner. In parallel, curcumin reduced differentiation-stimulated expression of CK1alpha, GSK-3beta, and Axin, components of the destruction complex targeting beta-catenin. Accordingly, quantitative PCR analysis revealed that curcumin inhibited the mRNA expression of AP2 (mature adipocyte marker) and increased the mRNA expression of Wnt10b, Fz2 (Wnt direct receptor), and LRP5 (Wnt coreceptor). Curcumin also increased mRNA levels of c-Myc and cyclin D1, well-known Wnt targets. These results suggest that the Wnt signaling pathway participates in curcumin-induced suppression of adipogenesis in 3T3-L1 cells.

AIMS: Korean red ginseng (unskinned Panax ginseng before it is steamed or otherwise heated and subsequently dried) is one of the most widely used herbal remedies. This systematic review evaluates the current evidence for the effectiveness of red ginseng for treating erectile dysfunction. METHODS: Systematic searches were conducted on 20 electronic databases without language restrictions. Hand-searches included conference proceedings and our files. All randomized clinical studies (RCT) of red ginseng as a treatment of erectile dysfunction were considered for inclusion. Methodological quality was assessed using the Jadad score. RESULTS: Seven RCTs met all the inclusion criteria. Their methodological quality was low on average. Six of the included RCTs compared the therapeutic efficacy of red ginseng with placebo. The meta-analysis of these data showed a significant effect (n = 349, risk ratio, 2.40; 95% CI of 1.65, 3.51, p < 0.00001, heterogeneity: tau(2) = 0.05, chi(2) = 6.42, p = 0.27, I(2) = 22%). Subgroup analyses also showed beneficial effects of red ginseng in psychogenic erectile dysfunction (n = 135, risk ratio, 2.05; 95% CI of 1.33, 3.16, p = 0.001, heterogeneity: chi(2) = 0.08, p = 0.96, I(2) = 0%). CONCLUSIONS: Collectively these RCTs provide suggestive evidence for the effectiveness of red ginseng in the treatment of erectile dysfunction. However, the total number of RCTs included in the analysis, the total sample size and the methodological quality of the primary studies were too low to draw definitive conclusions. Thus more rigorous studies are necessary.

Human gut microbiota plays important roles in harvesting energy from the diet, stimulating the proliferation of the intestinal epithelium, developing the immune system, and regulating fat storage in the host. Characterization of gut microbiota, however, has been limited to western people and is not sufficiently extensive to fully describe microbial communities. In this study, we investigated the overall composition of the gut microbiota and its host specificity and temporal stability in 20 Koreans using 454-pyrosequencing with barcoded primers targeting the V1 to V3 region of the bacterial 16S rRNA gene. A total of 303,402 high quality reads covered each sample and 8,427 reads were analyzed on average. The results were compared with those of individuals from the USA, China and Japan. In general, microbial communities were dominated by five previously identified phyla: Actinobacteria, Firmicutes, Bacteroidetes, Fusobacteria, and Proteobacteria. UPGMA cluster analysis showed that the species composition of gut microbiota was host-specific and stable over the duration of the test period, but the relative abundance of each member fluctuated. 43 core Korean gut microbiota were identified by comparison of sequences from each individual, of which 15 species level phylotypes were related to previously-reported butyrate-producing bacteria. UniFrac analysis revealed that human gut microbiota differed between countries: Korea, USA, Japan and China, but tended to vary less between individual Koreans, suggesting that gut microbial composition is related to internal and external characteristics of each country member such as host genetics and diet styles.

Although pelvic irradiation is effective for the treatment of various cancer types, many patients who receive radiotherapy experience serious complications. Gut microbial dysbiosis was hypothesized to be related to the occurrence of radiation-induced complications in cancer patients. Given the lack of clinical or experimental data on the impact of radiation on gut microbiota, a prospective observational study of gut microbiota was performed in gynecological cancer patients receiving pelvic radiotherapy. In the current study, the overall composition and alteration of gut microbiota in cancer patients receiving radiation were investigated by 454 pyrosequencing. Gut microbial composition showed significant differences (P < 0.001) between cancer patients and healthy individuals. The numbers of species-level taxa were severely reduced after radiotherapy (P < 0.045), and the abundance of each community largely changed. In particular, the phyla Firmicutes and Fusobacterium were significantly decreased by 10% and increased by 3% after radiation therapy, respectively. In addition, overall gut microbial composition was gradually remolded after the full treatment course of pelvic radiotherapy. In this set of cancer patients, dysbiosis of the gut microbiota was linked to health status, and the gut microbiota was influenced by pelvic radiotherapy. Although further studies are needed to elucidate the relationship between dysbiosis and complications induced by pelvic radiotherapy, the current study may offer insights into the treatment of cancer patients suffering from complications after radiation therapy.

AIMS: The aim of this study was to investigate the antiobesity effect of (-)-epigallocatechin-3-gallate (EGCG) in diet-induced obese mice. METHODS: Male C57BL/6J mice were fed on a high-fat diet for 8 weeks to induce obesity. Subsequently they were divided into 3 groups and were maintained on a high-fat control diet or high-fat diets supplemented with 0.2 or 0.5% EGCG (w/w) for a further 8 weeks. Changes in the expression of genes related to lipid metabolism and fatty acid oxidation were analyzed in white adipose tissue, together with biometric and blood parameters. RESULTS: Experimental diets supplemented with EGCG resulted in reduction of body weight and mass of various adipose tissues in a dose-dependent manner. EGCG diet also considerably lowered the levels of plasma triglyceride and liver lipid. In the epididymal white adipose tissue of EGCG diet-fed mice, the mRNA levels of adipogenic genes such as peroxisome proliferator-activated receptor-gamma (PPAR-gamma), CCAAT enhancer-binding protein-alpha (C/EBP-alpha), regulatory element-binding protein-1c (SREBP-1c), adipocyte fatty acid-binding protein (aP2), lipoprotein lipase (LPL) and fatty acid synthase (FAS) were significantly decreased. However, the mRNA levels of carnitine palmitoyl transferase-1 (CPT-1) and uncoupling protein 2 (UCP2), as well as lipolytic genes such as hormone sensitive lipase (HSL) and adipose triglyceride lipase (ATGL), were significantly increased. CONCLUSION: These results suggest that green tea EGCG effectively reduces adipose tissue mass and ameliorates plasma lipid profiles in high-fat diet-induced obese mice. These effects might be at least partially mediated via regulation of the expression of multiple genes involved in adipogenesis, lipolysis, beta-oxidation and thermogenesis in white adipose tissue.

The objective of this study was to determine the relationship between the plucking periods and the major constituents and the antioxidant activity in green tea. Green tea was prepared from leaves plucked from the end of April 2013 to the end of May 2013 at intervals of one week or longer. The contents of theanine, theobromine, caffeine, catechin (C), and gallocatechin gallate (GCg) were significantly decreased, whereas those of epicatechin (EC), epigallocatechin gallate (EGCg) and epigallocatechin (EGC) were significantly increased along with the period of tea leaf plucking. In addition, antioxidant activity of green tea and standard catechins was investigated using ABTS, FRAP and DPPH assays. The highest antioxidant activity was observed in relatively the oldest leaf, regardless of the assay methods used. Additionally, the order of antioxidant activity of standard catechins was as follows: EGCg≥GCg≥ECg>EGC≥GC≥EC≥C. Moreover, the cis-catechins contents were the key factor affecting the antioxidant activity of green tea in all assays employed (ABTS, r=0.731, p<0.01; FRAP, r=0.886, p<0.01; DPPH, r=0.778, p<0.01).