Byeong-Dae Choi

Accumulation of Conjugated Linoleic Acid (CLA) in Tissues of Fish Fed Diets Containing Various Levels of CLA

Conjugated linoleic acid (CLA) is reputed to have anticancer activity and is provided by our food supply. The objective was to raise premium quality fish containing this anticancer ingredient. This study has examined the CLA accumulated in lipids extracted from tissues of fish cultured with diets mixed respectively with CLA at 1.0%, 2.5%, 5.0% and 10.0%. The CLA was made by an alkaline isomerization method applied to safflower oil. The major CLA isomers, cis-9, trans-11 and trans-10, cis-12-18:2 dominated the total lipid CLA accumulation at over 80%, with other isomers below 20%. In addition to total lipids, CLA was detected in phospholipids of tissue in fish. Fish (carp) in the group fed the 1.0% CLA diet showed growth slightly faster or similar to those in the control group, while those in test groups fed 5.0% and 10.0% CLA diets showed retarded growth. The proper amount of CLA additive has proven to be 1.0% when taking into account the feed efficiency and specific growth rate. However, addition of CLA by including 5.0% in the diet has been proven the most effective way to obtain a high content of CLA in fish edible muscle

Chondroitin sulfate extracted from the Styela clava tunic suppresses TNF-α-induced expression of inflammatory factors, VCAM-1 and iNOS by blocking Akt/NF-κB signal in JB6 cells

Inflammatory mediators are known to play a key role in tumorigenesis, therefore, it is a promising strategy to inhibit the inflammation for cancer prevention and/or treatment. Current study was performed to investigate the effects of chondroitin sulfate (CS) extracted from Styela clava tunic on TNF-alpha-induced inflammation and to elucidate the mechanism of CS on the regulation of inflammatory factors in JB6 cells. Our results showed that CS inhibited TNF-alpha-induced NF-kappaB activation and subsequent vascular cell adhesion molecule 1 and inducible nitric oxide synthase expressions by blocking Akt signals in JB6 cells. Our results suggest that CS may be developed as an effective anti-inflammatory agent in the future.

Chondroitin Sulfate Extracted from Ascidian Tunic Inhibits Phorbol Ester-Induced Expression of Inflammatory Factors VCAM-1 and COX-2 by Blocking NF-κB Activation in Mouse Skin

Inflammatory factors are known to play a key role in promoting tumorigenesis; therefore, it is a promising strategy to inhibit the inflammation for cancer prevention. The current study was performed to investigate the potential effects of chondroitin sulfate (CS) extracted from ascidian tunic on the expression of inflammatory factors induced by treatment with 12- O-tetradecanoylphorbol-13-acetate (TPA) and to elucidate the underlying molecular mechanism of CS action in mouse skin inflammation. TPA was topically applied to the shaven backs of ICR mice with or without CS (1 or 2 mg) for 4 h. The results demonstrated that CS suppressed TPA-induced edema and reduced the expression of cyclooxygenase-2, vascular cell adhesion molecule-1, and Akt signaling in mouse skin. These studies suggest that CS from ascidian tunic may be developed as an effective natural anti-inflammatory agent.

Nutraceutical functionalities of polysaccharides from marine invertebrates.

Many researchers are seeking functional materials from marine resources. These marine resources can be used as traditional food additives, and specifically, these are based on polysaccharides. To date, there is a big opportunity to develop new high-value added products with indispensable functional characteristics, which can be used in nutraceuticals either as additives or supplements. Also, a crossover in the pharmaceutical market may be established. Some glycosaminoglycans (GAGs) mimetic-type molecules are already being utilized in the field of nutrition as well as in the cosmetics industry. This chemical is used as a dietary supplement to maintain the structure and function of cartilages, for the relief of pain caused by osteoarthritic joints, and can also be used as an anti-inflammatory agent. Recently, in relation to the prevalence of mad cow disease and avian influenza, the production of GAGs from marine invertebrates offers new market opportunities as compared with that obtained from bovine or avian livestock.

Enzyme-assisted extraction of anticoagulant polysaccharide from Liparis tessellatus eggs.

This study aimed to recover a heparin-like anticoagulant polysaccharide from Liparis tessellatus eggs (PLE) by using enzyme-assisted extraction technique. Extraction experiments were carried out using three different enzymes (Alcalase®2.4 L, Flavourzyme®500 MG, and Protamex®) under different conditions of temperature (45, 50, and 55°C), pH (6.5, 7.0, and 7.5), incubation time (24, 36, and 48 h), and enzyme to substrate ratio (E/S=0.5, 1.0, and 1.5%, w/w), which were combined according to a D-optimal design. Statistical analysis of extraction results allowed identifying the variables with greater influence on the extraction yield, and selecting the conditions that maximize the PLE extraction. The best extraction results were achieved when using the Protamex® enzyme in an E/S ratio of 1.34% (w/w), pH 6.60, 47.40°C, during 26.50 h. Under these conditions, a polysaccharide yield of 2.10% (w/w) was obtained. Clotting time measurements, activated partial thromboplastin time, and prothrombin time for evaluation of the anticoagulant properties of PLE were determined and showed increasing activities in correlation with the concentrations used. In the final step, the heparin-like nature of PLE was confirmed by digestion with heparinases I, II, and III, which showed ΔDiHS-0S, ΔDiHS-6S, ΔDiHS-diS1, and ΔDiHS-diS2 at compositions of 0.04, 0.03, 0.35, and 0.24 mol/g, respectively.

The development of imitation crab sticks by substituting spent laying hen meat for Alaska pollack

Imitation crab stick (ICS) samples were divided into 5 treatments, a control composed of commercial ICS containing no breast meat from spent laying hens, and treatments 1, 2, 3, and 4, in which 5, 10, 15, and 20% batter from breast meat of whole spent laying hens was substituted for Alaska pollack surimi, respectively. Imitation crab stick samples containing spent laying hen breast meat batter showed significantly (P < 0.05) higher moisture levels than the control sample. However, the myoglobin and metmyoglobin levels did not differ significantly (P > 0.05) among ICS samples. During storage, whiteness was greater in the control sample than in the ICS samples containing spent laying hen breast meat batter. The saturated and monounsaturated fatty acids increased, whereas the polyunsaturated fatty acids decreased in response to substituting surimi with spent laying hen breast meat batter. The moisture content and pH were increased as the amount of spent laying hen breast meat batter increased. The lipid oxidation value (TBA-reactive substances) and protein degradation value (volatile basic nitrogen) tended to increase during storage as the amount of spent laying hen breast meat batter increased. None of the sensory evaluation items differed among ICS samples during storage, although the color of the final products, mechanical color (by colorimeter), and textural properties did differ among samples. These results indicate that substituting laying hen breast meat batter for Alaska pollack surimi is a very useful method for the production of ICS because it enables the use of a simple production process that does not require steps, such as washing or pH adjustment, for myofibrillar protein recovery.

Identification of cellulolytic bacteria associated with tunic softness syndrome in the sea squirt, Halocynthia roretzi

The edible ascidian, sea squirt Halocynthia roretzi (Drasche) is marine invertebrate that is a valuable source of foods and bioactive compounds. A severe disease of the sea squirt characterized by degeneration of tunic fibers formed of bundled cellulose microfibrils has occurred. We hypothesized that bacteria lyse the cellulose fibril structure, cellulase activity may be a causative agent of the disease. Among the bacteria isolated from diseased sea squirt, Pseudoalteromonas sp. NO3 had cellulase activity based on a Congo red overlay assay and starch-reducing activity. Sea squirts exhibited 40–100% cumulative mortality after injection with Pseudoalteromonas sp. NO3 using doses of 2×106−2×108 colony forming unit (CFU)/individual. Dead sea squirts possess thinner and ruptured tunics, which were similar to natural outbreaks. These results suggest that Pseudoalteromonas sp. NO3 possessing cellulase activity is one of the causes of tunic softness syndrome in sea squirt.

Hyaluronidase-inhibitory activities of glycosaminoglycans from Liparis tessellatus eggs

Polysaccharide fractions isolated from L. tessellatus eggs were purified and eluted using the DEAE-sepharose fast flow column. These were collected, tested and pooled based on their sugars content: F1, F2, and F3 which contain 26.8, 23.3, and 20.2% sulfated glycans; 34.5, 38.2, and 45.0% uronic acids; and 23.5, 19.0, and 7.5% acetylhexosamines and hexosamines, respectively. Hyaluronidase inhibitory effects of the fractions are in the order F3>F2>F1>Ascorbic acid, with F3 having the highest inhibition among the fractions and that of the standard, ascorbic acid. The electrospray ionization tandem mass spectrometry (ESI-MS/MS) confirmed the presence of uronic acids on F3, which could be a 0,2A2 fragment plus loss of methyl group which is very common among non-methylated, sulfated disaccharides.

Skin regeneration effect of the Glycosaminoglycans from Liparis tessellatus eggs

A purified Glycosaminoglycans (GAGs) extract from L. tessellatus eggs was enzyme-hydrolyzed and then fractionated with DEAE-Sepharose column chromatography. The fractions were subsequently subjected to skin regeneration effects analysis against skin fibroblast (CCD-986sk) cell lines. Fraction 3 is evidently to have tyrosinase inhibition activity by 20.1% at concentration of 50mg/mL. DOPA oxidation assay, collagenase inhibition activity assay, fibroblast proliferation assay, and production of type I C-peptide assays were done to further proof the skin regeneration effect of GAGs fractions. Results revealed that fraction 3 has effective skin regeneration activities at a concentration of 200mg/mL.

Seasonal variations of nutritional components in cockles (Tegillarca granosa) processed from the Southern Coast of Korea

Abstract Cockles (Tegillarca granosa) species that found throughout the Indo-Pacific region and this study was conducted in South Korea from late autumn (November 2015) through early spring (April 2016). The proximate composition, mineral content, free amino acid, and fatty acid (FA) profiles and the nutritional quality of the cockles were studied at different stages during the processing. The contents of protein (11.7–13.9/100 g), lipids (1.1–2.5/100 g) and ash (1.6–2.7/100 g) varied significantly (p < 0.05) based on seasonal variations and processing steps. Taurine, glutamic acid, lysine and arginine were the most abundant amino acids in the amino acid profiles. All samples contained limited concentrations of Cr, Pb, Cd, As, and Co. The FA profiles showed that n-3 polyunsaturated FA (PUFA) were the major fatty acids (28.7–37.0% of total FA, which was predominantly DHA and EPA (7.9–17.4%). Saturated FA (SFA) and monounsaturated FA (MUFA) levels were also observed throughout the experiment, as well as n − 3/n − 6 and PUFA/SFA ratios. The data obtained from this study may be useful to indicate the periods of the harvest season more suitable for consumption and the importance of processing chain on quality of cockle.