Imidazole dipeptides have been elucidated to have a variety of functionalities and are now being put to practical use. Recently, it was discovered that the muscle of a fish called Lampris guttatus (mandai) contains a high concentration of "balenine" a type of imidazole dipeptide. This fish species belongs to the order Lampriformes in terms of classification, and the closely related species is the oarfish. It is caught together with tuna in pelagic longline fisheries, but its trade price is lower than that of tuna and it is underutilized. The extract powder extracted from the meat of L. guttatus contained 30% or more of balenine, and it was possible to obtain high purity balenine of more than 95% by treatment such as ion-exchange resin column and recrystallization. Balenine purified from L. guttatus had an antioxidant capacity equal to or higher than that of carnosine and anserine. When orally administered to mice, it was absorbed from the intestinal tract and detected in blood. The blood levels of balenine were higher than that of carnosine given in the same dose and was maintained for a long time.

Whip stingray (Dasyatis akajei) is unused resource in fisheries of Tokyo bay. Cartilaginous fish including stingray contain chondroitin sulfate (CS) in cartilage. CS has functionality as suppression of joint pain, stiff shoulder and dry eye and so on. We have investigated CS content of cartilage in edible part of stingray caught in Tokyo bay. Average CS contents of whip stingray's cartilages were 8.83 mg/g to be equal to double amount of blue shark's spine used as major material of CS for pharmaceuticals. High content of CS of stingray's cartilage can be used as appeal element for utilization as healthy food. So Japan Fisheries Research and Education Agency, Fisheries research center of Chiba prefecture and Algamarina Co. Ltd. have collaborated and developed new product containing CS made from whip stingray. In tasting test of the new product, it was asked by a lot of people that how amount of intake of the new product was need for maintain health caused by CS. So it was necessary to elucidate functional mechanism of CS taken by new food product.

In 2010, an interesting paper on Japanese-dish lovers and seaweed lovers was reported by Hehemann, et al., entitled “Transfer of carbohydrate-active enzymes from marine bacteria to Japanese gut microbiota,” and was published in Nature. This report showed that red algae polysaccharide-degradation enzyme (agarase and porphyranase) genes of some marine bacteria were transferred to Bacteroides prebeius, which has been detected in Japanese volunteers, but not in North Americans. This result is regarded compelling because it shows the first evidence of horizontal gene transfer in the gut, amidst the high concentration of various bacteria, as mentioned above. However, some Japanese media used phrases such as "Seaweed can only be used by Japanese gut." Is this correct? In traditional Japanese cuisine, various materials consisting of three types of macroalgae (brown, red, and green algae) have been used. The colours are caused by their important photosynthetic pigments, and brown and red algae also contain unique polysaccharides. For example, laminaran, alginate, and fucoidan are present in brown algal water-soluble polysaccharides. Two water soluble polysaccharides in brown algae alginates and laminaran can be fermented by gut microorganisms of human (not only Japanes) and laboratory animals. Alginate and laminaran increased the murine caecal B. acidifaciens and B. intestinalis, respectively. The isolated B. acidifaciens and B. intestinalis could ferment each polysaccharide and produced mainly succinate and lactate, respectively. The combination of algae and algal polysaccharide intake and its susceptible gut indigenous bacteria (SIB) cells and their metabolites is thought to contribute to host health.

The number of patients exhibiting allergies in developed countries like Japan is increasing; allergies have become a societal issue. While diverse remedies and strategies are employed in the medical and pharmaceutical fields, anti-allergic compounds have also been investigated for the prevention and alleviation of allergies. Phenolic compounds from terrestrial food materials are well-known as typical anti-allergic components including flavonoids and tea catechins. Phenolic compounds are also present in seaweeds, such as species in the brown alga genera Ecklonia and Eisenia, and these are collectively known as phlorotannins. The anti-allergic effects of phlorotannins were have been repeatedly demonstrated. Here, we have reviewed the general properties and bioactivities of phlorotannins and provided a detailed description of the anti-allergic effects of the brown alga Eisenia nipponica and phlorotannins isolated from it. We have also reviewed the anti-allergic effects of the brown alga Ecklonia cava subsp. stolonifera as well as its phlorotannins and discussed the potential use of these algae in functional foods.

Selenonein is an organic selenium-containing compound found in blood of tuna and has strong antioxidant capacity. Thus, selenoneine-containing materials for functional foods have been developing from marine processing residue containing selenoneine abundantly. Our previous studies found new functions of selenoneine such as the inhibition of angiotensin-converting-enzyme (ACE) and melanin synthesis by in vitro and in cellulo experiments. Based on the enzyme kinetics, selenoneine was suggested to exert its inhibitory activity by chelating metal ions such as zinc and copper ions existing in the active center of ACE and tyrosinase, involved in melanin synthesis. In recent years, we have succeeded in a development of a method for the separation of selenonein monomer, which was previously difficult. Currently, the metabolism of selenonein has been studying by administering stable isotope (Se-76)-labeled selenonein obtained from a selenoneine producing fission yeast strain to mice.

Products prepared from extracellular matrix proteins have been distributed as functional food materials. Some of these are in the form of protein degradation products or peptides to improve water solubility. Among these peptides, it has been reported that skin conditions and joint pains are improved after ingestion of fishderived elastin and collagen peptides. The mechanism of the beneficial effect is thought to be that the lowmolecular-weight peptides absorbed into the bloods after ingestion exert as active components. In this paper, we introduce the peptides that increase in blood after elastin peptide and collagen peptide ingestion, as well as the concentration of peptides absorbed after fish-derived gelatin ingestion, which is a higher molecular weight.

Marine products mostly come from natural resources, and many of them are unused because of their below-standard variety, size, etc. Here I introduce four cases where these resources were utilized for product development according to the regional needs.

Street food and fish-boning tool

To respond to a request from Odawara City to develop a local fish product that sightseers can enjoy while strolling, we worked on making a wholly eatable kamasu, or small-sized barracudas, and invented a straw-shaped boning device. Deep-fried kamasu boned with this tool is now marketed as “Kamasu-bo”. Odawara City registered “Hojo-ippon-nuki” as a trademark of fish products boned with this tool, and Kanagawa Prefectural Government acquired a patent of the tool.

New tuna product in Misaki, Miura City

Receiving a request from a tuna processing company to develop the world's most delicious tuna product, we examined a method combining confit, a French cooking technique, with low-temperature vacuum cooking. Studying suitable pretreatment, heating conditions, etc., we successfully made a product with rich taste and chicken-like texture from low-fat white tuna. Now it is sold as “Maguro Confit” at a high-end supermarket Seijo Ishii. Other low-priced fish are processed in this method and marketed.

Utilization of unwanted sea urchins that damage coastal seaweed

In utilizing purple sea urchins eliminated to prevent damage on seaweed, we focused on their omnivorousness. We cultivated them feeding cabbage grown in Miura instead of seaweed. The urchins showed a good appetite, and their gonad, the edible part, grew larger and sweeter having almost no bitterness and sea smell. They are named “Kyabetsu-uni”.

Noodle from seaweed utilizing its sodium egestion function

Noodles are usually high in salt. Requested to develop a noodle with reduced salt, we focused on algin acid in seaweed that helps egest sodium. Using brown seaweed stem and large brown alga as ingredients, we developed a processing method that prevent elution of algin acid even when boiled. After five-day consumption, an increase in sodium egestion and bowel movement frequency was confirmed. The new noodle is sold as “Isohana-matsumo-men”.

Chlorela, Chlorella pyrenoidosa, has a long history of usage as food supplements. It has been reported that chlorella and its hot water extract exhibit beneficial activities, such as anti-dyslipidemic activity, upon oral administration. However, little was known for the active compounds responsible for the beneficial activities. The present review introduces recent findings of active compound in chlorella. Phenethylamine, decarboxylated phenylalanine, was identified as active compound in chlorella hot water extract by life-span extending assay using superoxide dismutase (SOD)-1 gene (Sod1)-knocked out Drosophila melanogaster. An animal experiment also demonstrated that phenethylamine mitigated high fat diet (HFD)-induced liver damage. lipid peroxidation in liver, and plasma hyper low-density lipoprotein cholesterol of mice (C57BL/6J) upon oral administration (10 μg/kd body weight) without markedly decreasing lipid accumulation in liver. In addition, phenethylamine maintained glyceraldehyde-3-phosphate dehydrogenase (GAPDH) protein level in the liver, which suppressed generation of methylglyoxal from substrates of GAPDH. Suppression of toxic aldehyde generation by phenethylamine was also confirmed by maintaining hepatic cysteine, highly reactive to aldehydes. These findings provide new theory that decrease of GAPDH by HFD feeding increases generation of methylglyoxal, which triggers oxidation of accumulated lipid and consequently induces liver damage. Trace amounts of phenethylamine alleviate high fat diet-induced liver damage by regulating methylglyoxal via maintaining

Providing foods which can maintain and improve our health is an important issue for both developed and developing countries today. Fish and marine products are known as those effective foods. People have been eating fish for a long time. And its high quality protein, lower calories and improving brain function have attracted our attentions.

“MANDAI” (opah: Lampris guttatus), the fish that we handle, is mainly landed as a bycatch of tuna. The meat color, texture and taste of “MANDAI” is similar to those of tuna, so that it has been eaten by us for years. Recent research has shown that it contains high amount of balenine, a type of imidazole dipeptide. Balenine, however, compared to carnosine and anserine which are found in livestock, bonito and tuna, is still a minor nutrition. For that reason, balenine has not been studied much. In order to show that “MANDAI” is a useful source of balenin for research, we investigated some states of balenine in it.

First, we studied the distribution of balenine in its whole body and found that normal muscle is suitable for extract production. Also, we found out that it is important to check the color of the muscle, in order to obtain a stable concentration of balenine in the extract. Furthermore, we have found an effective knowledge for the production of high purity balenine. At the same time, the optical purity of the balenine from “MANDAI” was almost the same as that of the commercial standard. These results reveal that “MANDAI” is a promising material for future functional research of balenine.

Delphinidin, cyanidin and pelargonidin (anthocyanidins) are the group of aglycons of anthocyanins that are the natural compounds derived from reddish vegetables and fruits. Anthocyanidins exhibit various biological activities including anti-oxidative effects; however, their activity of anti-bone resorption was still not known. We have reported that anthocyanidins showed bone protective effects through the inhibition of osteoclast differentiation. Anthocyanidins inhibited IL (interleukin)-1 and LPS (lipopolysaccharide)-induced osteoclast differentiation and bone-resorbing activity in mouse calvarial organ cultures. In osteoblasts, anthocyanidin suppressed PG (prostaglandin) E₂ production through the downregulation of Ptges (membrane-bound prostaglandin E synthase) expression that resulted in Rankl (receptor activator of NF-κB ligand) suppression. In osteoclasts, anthocyanidins inhibited RANKL-induced osteoclast differentiation by downregulated the osteoclast functional genes such as Nfatc1 (nuclear factor of activated T cells, cytoplasmic 1), Ctsk (cathepsin K) and Acp5 (acid phosphatase 5, tartrate resistant).

We further demonstrated that delphinidin directly suppressed IKK (inhibitor of NF-κB kinase) activity in vitro assay. Besides, in silico assay indicated that delphinidin binds to the ATP binding pocket of IKK protein. These data suggest that anthocyanidins attenuate IKK-NF-κB signaling via the direct inhibition of IKK activity, resulting in inhibiting PGE2-mediated osteoclast differentiation. The effects of anthocyanidins depended on the number and the position of hydroxyl groups and methoxy groups of the B ring. This review described that the function of the anthocyanidins for the anti-bone resorptive effects. The utilization of anthocyanidins as the functional food with compounds for maintaining bone health contributes to promote human locomotive activity in current super-aged society.

Human health is maintained by daily dietary food consumption to prevent lifestyle-related diseases in the super-aged society of Japan. Citrus-derived bioactive natural compounds including xanthophylls and polyphenols possess various beneficial effects such as antioxidative effects. Recently, the physiological activities of the foods have been elucidated that applied to functional foods development for various agricultural products. The high quality of qualitative and quantitative analysis for bioactive natural compounds contained functional foods has been increased the importance in the field of agricultural research communities. Liquid chromatography-mass spectrometry (LC-MS) is generally applied to the qualitative and quantitative analysis of many agricultural products containing functional food components. On the other hand, the spatial distribution of the bioactive natural compounds in the plant tissues is needed to develop a novel index for quality control of agricultural products. Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) is an advanced technique for the analysis of the spatial distribution of components. MSI is to perform the direct mass spectrometry to the tissue surface, resulting in the visualization of target molecules showing a specific mass spectrum. In this study, we analyzed the distribution of natural compounds on the citrus tissue by MSI and further demonstrated that the evaluation of the functional evidence of the physiological activities using the mouse model. We suggest that the MSI technique is applied to the development of functional food through the spatial distribution of bioactive natural compounds on the tissues of agricultural products.

Prevention of crop damage by plant-parasitic nematodes (PPNs) is a current important issue. Plant-derived reactive oxygen species (ROS) affect pathogens including PPNs directly and induce immune responses simultaneously. In resistant varieties of wheat and tomato, ROS production is increased at the infection site of nematodes as compared to susceptible cultivars. Intriguingly, PPNs are able counteract various oxidative stresses during parasitism. E.g., PPNs secrete peroxiredoxin to scavenge external ROS resulting in successful parasitism. Further examples are protein disulfide isomerase, glutathione peroxidase and transthyretin-like proteins with catalytic subunits that are produced by infecting nematodes. These nematode-derived enyzmes are supposed to fine tune the redox status at the pathogen-host interface. On the other hand, ROS production by respiratory burst oxidase homolog (RBOH) in the host plant was found to be essential for parasitism of cyst nematodes. Although several nematode effectors involved in ROS signaling have been identified, the complex interactions between PPNs and their hosts are far from being fully understood. Nematicides are used to control PPNs in agriculture, but due to environmental, user, and consumer safety more and more of these mostly highy toxic compounds are banned or withdrawn from the market. Therefore, there is an urgent demand for alternatives including specific agrochemicals and breeding of new crop varieties. The analysis of the role of ROS in nematode-host interactions may lead to insights facilitating the development of such approaches. In this review, we summarize current topics in this field of crop sciences.

The number of patients exhibiting allergies in developed countries like Japan is increasing; allergies have become a societal issue. While diverse remedies and strategies are employed in the medical and pharmaceutical fields, anti-allergic compounds have also been investigated for the prevention and alleviation of allergies. Phenolic compounds from terrestrial food materials are well-known as typical anti-allergic components including flavonoids and tea catechins. Phenolic compounds are also present in seaweeds, such as species in the brown alga genera Ecklonia and Eisenia, and these are collectively known as phlorotannins. The anti-allergic effects of phlorotannins were have been repeatedly demonstrated.

Here, we have reviewed the general properties and bioactivities of phlorotannins and provided a detailed description of the anti-allergic effects of the brown alga Eisenia nipponica and phlorotannins isolated from it. We have also reviewed the anti-allergic effects of the brown alga Ecklonia cava subsp. stolonifera as well as its phlorotannins and discussed the potential use of these algae in functional foods.

It is difficult to separate and recover chitosan oligosaccharides (COS) by the degree of polymerization (DP) or by the narrow range of molecular weights in an industrial large-scale. COS solution was precipitated by adding hydrochloric acid (HCl) at a final concentration of 2 M to 12 M. After the suspension was filtrated and its precipitate was dissolved by pure water, the dissolved precipitate and the filtrated solution were concentrated to dryness. They were dissolved again, adjusted at pH 4, lyophilized respectively, and then the precipitated fraction and the liquid fractions were obtained. In the precipitated fraction of 10% COS solution obtained by final concentration of HCl at 2 M to 4 M HCl included abundant COS DP8-DP10 (Weight-average molecular weight, Mw of precipitated fraction: 5,200-5,600). In the liquid fraction of 10% COS solution obtained by final concentration of HCl at 4 M to 6 M included abundant COS DP4-DP6. These results suggest that HCl precipitation of COS solution is a useful preparative method that can easily separate a large amount of COS by molecular weight.

Objective: Aurantiochytrium (Aura), a microalgae, efficiently synthesizes and accumulates n-3 unsaturated fatty acids such as DHA. It is expected to be applied to functional foods. In this study, we investigated the effect of Aura extract intake on improving spontaneous osteoarthritis (OA) mice and muscular atrophy mice.

Methods: Aura oil extract was administered to spontaneous OA mice STR/Ort mice, and the condition of the knee joint tissue was observed. Three groups were set: female mice on a non-OA control diet (non-OA), male mice on an OA control diet (OA-Cont), and OA Aura oil extract (OA-Aura O). The muscular atrophy mouse model was created by fixing the hind legs of Slc: ICR mice (8 weeks old). Non-fixed + Control diet administration group (Non-fixed Cont), Fixed + Control diet administration group (Fixed-Cont), Fixed + Aura oil extract administration group (Fixed-Aura O), Fixed+Aurantiochytrium algae administration group Four groups of (Fixed-Aura) were set. The test substance was administered for 3 weeks during the preliminary breeding period. After 2 weeks of fixation, autopsy was performed to measure body weight, muscle wet weight, and muscle fiber cross-sectional area.

Results and Discussion: In OA model, the OA status of the knee joint in the Aura O-administered group showed a tendency to improve the average score in both the OARSI method (p = 0.18) and the Mankin method (p = 0.16). Therefore, it was suggested that OA progression was suppressed by administration of Aura O. In the muscle atrophy model, administration of Aura extract was observed to restore the cross-sectional area of the soleus muscle fibers. In the Fixed-Aura O group, the expression level of Atrogin-1, an ubiquitin ligase in the gastrocnemius muscle, decreased, suggesting that suppressing proteolysis may have improved muscular atrophy.

In recent years, syrup, prepared by soaking fruit in sugar solution and subsequent yeast fermentation, has attracted attention. In syrup, improving functionality is expected because the components in fruits are altered by fermentation. We need to evaluate the functionality of each fruit as the functionality depends on the type of fruit and yeast. Many kinds of components are related to improved functionality, and it has been reported that the main component is polyphenol. In this study, we investigated the changes in antioxidant activity, α-glucosidase inhibiting activity, lipase inhibiting activity, and total polyphenol content during fermentation periods (7-21 d) in syrup and the relationship between functionality and total polyphenol content. We also investigated antioxidant activity and total polyphenol content in heated and non-heated syrup to evaluate the change of antioxidant activity and total polyphenol content by heating. As a result, the antioxidative effect increased from 33.4% after 7 d to 97.9% after 21 d. α-glucosidase inhibition activity was 65.4% after 7 d, which increased to 102% after 14 d, and 97.9% after 21 d. Lipase inhibition decreased from 6.58% in 7 d to 1.53% in 21 d. Total polyphenol increased from 7.71 mg/g in 7 d to 15.0 mg/g in 21 d. The antioxidative effect and α-glucosidase inhibiting activity increased with increasing total polyphenol content, and the correlation of antioxidative effect and total polyphenol content from 7 d to 21 d showed an R² value of 0.966. Therefore, it was found that total polyphenol greatly contributed to improved functionality. In addition, antioxidant activity and total polyphenol content in heated syrup was higher than non-heated syrup.

Quercetin is known to have high antioxidant activity. The onion peel (OP) contains high concentrations of quercetin. Therefore, it is considered that the antioxidant activity works in the body by ingesting OP. However, OP must be cooked with other foods for ingestion. It is suggested that cooking changes the OP antioxidant activity. Therefore, the purpose of this paper is to examine the effect of cooking on the antioxidant activity of OP.

Forty-eight recipes with OP powder added were considered and cooked. In addition, the recipes were cooked without the addition of OP powder. A total of 96 dishes were decomposed into sample solutions. The fat soluble and water-soluble antioxidant activity of the sample was measured by the DPPH (1,1-diphenyl-2 picrylhydrazyl) method. Furthermore, the 51 ingredients used in each recipe were calculated based on the Standard Tables of Food Composition in Japan. The relationship between the measured antioxidant activity of OP and cooking method, and contained components was determined. From this relationship, the factors affecting the antioxidant activity of OP powder were investigated.

The antioxidant activity of recipes by adding OP powder increased by 36 recipes (75%) for fat-soluble and 27 recipes (56%) for water-soluble. The average rate of increase in antioxidant activity by OP was 1.34 ± 0.48 for fat-soluble and 1.06 ± 0.29 for water-soluble. The fat-soluble antioxidant activity was significantly higher by the addition of OP (p < 0.01), and no significant difference was shown in water solubility.

In the "Stir-fried" cooking method by OP, the fat-soluble antioxidant activity showed a significantly high value (mean value: 1.66 ± 0.67) (p < 0.05). Regarding food ingredients, insoluble dietary fiber, water-soluble dietary fiber, total dietary fiber (p < 0.01), and potassium, iodine, and iron (p = 0.01, 0.01, 0.05, respectively) significantly increase fat-soluble antioxidant activity. Molybdenum (p = 0.05) significantly increase water-soluble

In the patients of acute liver injury, it is important to delay the progression and severity of hepatic damage. In this research, the antioxidant effects of the additive Profine® (PF), a product derived from Japanese sake lees, were tested in two different types of acute liver injury in rat models, as follows: a green tea extract (GTE)induced liver injury model and a carbon tetrachloride (CCl₄)-induced liver injury model. Seven-week-old male Sprague-Dawley rats received a single intraperitoneal injection of 50% CCl₄ or 200 mg/kg GTE. Serum and liver samples were collected 48hrs after the CCl₄ or GTE injection. In separate groups, 2 mL of 2, 4, or 8% PF in water was orally administered multiple times before and after CCl₄ or GTE injection. Serum biomarkers of hepatotoxicity (AST, ALT, T-BIL), histopathology, and/or immunohistochemistry of apoptosis, oxidative stress and hypoxia were examined. These marker levels were decreased in PF exposure groups compared to CCl₄- injected group. Suppression of GTE-induced hepatotoxicity was also seen with 2, 4, and 8% PF administration. Our experimental results demonstrate that PF reduced the severity of liver injury in these models by its antioxidant activity.