You-Jin Jeon

Food applications of chitin and chitosans

Abstract Chitin is the second most abundant natural biopolymer after cellulose. The chemical structure of chitin is similar to that of cellulose with 2-acetamido-2-deoxy-β- d -glucose (NAG) monomers attached via β(14) linkages. Chitosan is the deacetylated (to varying degrees) form of chitin, which, unlike chitin, is soluble in acidic solutions. Application of chitinous products in foods and pharmaceuticals as well as processing aids has received considerable attention in recent years as exotic synthetic compounds are losing their appeal. This review summarizes some of the important developments related to food applications of chitin, chitosan and their derivatives.

Production of chitooligosaccharides using an ultrafiltration membrane reactor and their antibacterial activity

Abstract To increase the solubility of chitosan in an aqueous solution and to facilitate its utilization, the enzymatic production of chitooligosaccharides with a high degree of polymerization (DP) was carried out using an ultrafiltration (UF) membrane reactor system. 80% of the oligosaccharides produced were in the range DP3–6. Compared with a batch reactor, in the UF membrane reactor system, at least 11 batches of substrate could be hydrolysed for the same quantity of chitosanuse. Oligosaccharides obtained using the reactor system showed antibacterial activity and a 0.5% concentration completely inhibited the growth of Escherichia coli .

Improvement of functional properties of cod frame protein hydrolysates using ultrafiltration membranes

Abstract Enzymic hydrolysis was applied for the efficient recovery of the protein sources from the fish processing by-product, cod frame. The enzyme used for the hydrolysis was crude proteinase extracted from tuna pyloric caeca. The resultant hydrolysate, cod frame protein hydrolysate (CFPH), was separated based on the molecular weight of the peptides in the hydrolysate and several functional properties were examined, including physicochemical properties (emulsifying and foaming property) and bioactivities (antioxidative and angiotensin I converting enzyme (ACE) inhibitory activity) to determine its potential functions. CFPH was processed through a series of ultrafiltration (UF) membranes with molecular weight cut-off (MWCO) of 30, 10, 5 and 3 kDA, and four types of permeates including 30-K (permeate from 30 kDA), 10-K (permeate from 10 kDA), 5-K (permeate from 5 kDA) and 3-K hydrolysate (permeate from 3 kDA) were obtained. 10- and 30-K hydrolysates showed excellent emulsion properties and whippability. The 10-K hydrolysate showed high antioxidative activity, while the 3-K hydrolysate had excellent ACE inhibitory activity. In terms of all functional properties tested, the fractionated hydrolysates were superior to the original non-separated hydrolysate. These results suggested that separating hydrolysate enhanced several functional properties.

PREPARATION OF CHITIN AND CHITOSAN OLIGOMERS AND THEIR APPLICATIONS IN PHYSIOLOGICAL FUNCTIONAL FOODS

Chitin and chitosan are known to possess multiple functional properties. Chitin is insoluble in any common solvent containing organic or mineral acid as well as water. Chitosan is water-insoluble and highly viscous in dilute acidic solutions. These solubility problems may restrict their use in physiological functional foods. However, chitin and chitosan oligomers are not only water-soluble and their solutions have low viscosity values, but they may also be absorbed in the human intestine. They may have much physiological functionality in the in vivo systems. This review demonstrates that chitin and chitosan oligomers can be prepared by chemical and enzymatic hydrolyses and that the oligomers with high degrees of polymerization, especially those with six residues or more, show strong physiological activities.

Antioxidative activity of chitosans of different viscosity in cooked comminuted flesh of herring (Clupea harengus)

Antioxidant efficacy of chitosans of different viscosity (14 cP, 57 cP and 360 cP) in cooked, comminuted flesh of herring (Clupea harengus), was investigated. The oxidative stability of treated fish flesh was determined and compared with those treated with conventional antioxidants, such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tert-butylhydroquinone (TBHQ) at a level of 200 ppm. The progress of oxidation was monitored by employing the peroxide value, 2-thiobarbituric acid-reactive substances (TBARS) and static headspace gas chromatographic analysis. In general, all chitosans exhibited varying antioxidant activities in a fish flesh model system. The formation of hydroperoxides and TBARS, in herring samples containing 200 ppm 14 cP chitosan, was reduced after 8 days of storage by 61 and 52%, respectively. Among the different viscosity chitosans, 14 cP chitosan was more effective than the higher viscosity chitosans in preventing lipid oxidation in the herring flesh model system.

Continuous production of chitooligosaccharides using a dual reactor system

Abstract The continuous production of chitooligosaccharides from chitosan was achieved with a dual reactor system which consisted of an ultrafiltration (UF) membrane reactor and a column reactor packed with an immobilized enzyme. The production of the oligosaccharides was performed by two steps, the first, the preparation of the partially hydrolyzed chitosan (PHC) from viscose chitosan in the column reactor packed with an enzyme and the second, the production of the oligosaccharides from PHC in the UF membrane reactor. Three kinds of PHCs were obtained from three different outflow rates (3, 5, and 9 ml/min) in the column reactor and were supplied to a substrate feed tank of the following UF reactor in order to identify the influence of the feed on membrane fouling. The PHC obtained with a 5 ml/min overflow rate was the most suitable substrate for alleviation of membrane fouling and efficient hydrolysis under the operating conditions of the dual reactor system. In addition, chitooligosaccharides produced using the dual reactor system were readily fractionated by a proper selection of membranes. Therefore, it was shown that this dual reactor system was adequate for continuous production of chitooligosaccharides from chitosan by enzymic hydrolysis.

Inhibition of tumor growth in vitro and in vivo by fucoxanthin against melanoma B16F10 cells.

The present study was designed to evaluate the molecular mechanisms of fucoxanthin against melanoma cell lines (B16F10 cells). Fucoxanthin reduced the proliferation of B16F10 cells in a dose-dependent manner accompanied by the induction of cell cycle arrest during the G(0)/G(1) phase and apoptosis. Fucoxanthin-induced G(0)/G(1) arrest was associated with a marked decrease in the protein expressions of phosphorylated-Rb (retinoblastoma protein), cyclin D (1 and 2) and cyclin-dependent kinase (CDK) 4 and up-regulation of the protein levels of p15(INK4B) and p27(Kip1). Fucoxanthin-induced apoptosis was accompanied with the down-regulation of the protein levels of Bcl-xL, an inhibitor of apoptosis proteins (IAPs), resulting in a sequential activation of caspase-9, caspase-3, and PARP. Furthermore, the anti-tumor effect of fucoxanthin was assessed in vivo in Balb/c mice. Intraperitoneal administration of fucoxanthin significantly inhibited the growth of tumor mass in B16F10 cells implanted mice.

Food Quality of Rainbow Trout Oncorhynchus mykiss Domesticated in Seawater

This study compared the food quality of domesticated(RT-DS) and freshwater (RT-F) rainbow trouts Oncorhynchus mykiss. The proximate composition of RT-DS was 73.8% moisture, 20.6% crude protein, 4.2% crude lipid, and 1.1% ash and was similar to RT-F. No differences were found in the red color, odor a...

Preparation of Commercial Agarose from Jeju Seaweed, Gelidium amansii using DMSO Extraction and EDTA Washing

Agar was prepared from Gelidium amansii collected from Jeju Island, South Korea. This agar preparation has high gel strength and low sulfate content compared with G. amansii agar from Morocco. Accordingly, agarose was made from the Jeju agar through the consecutive refi ning processes of dimethyl sulfoxide (DMSO) extraction and ethylene diamine tetra acetic acid (EDTA) washing. The physicochemical properties of the resulting agarose were compared with those from agarose prepared using only DMSO extraction. Consecutive DMSO extraction and EDTA washing more strongly affected the physicochemical properties of the agarose (purifi ed agarose) compared with the use of DMSO extraction alone. These properties were similar to those of commercial agarose used for electrophore- sis. In DNA electrophoresis, the separation and movement speed of the purifi ed agarose were similar to those of the commercial agarose. In a 13 C NMR analysis, the purifi ed agarose exhibited the same carbon peak as the commercial agarose. When observed under scanning electron microscopy, the agar had an even and smooth surface without ir- regularities or pores, and the purifi ed agarose had a wide surface area with a large number of pores; the commercial agarose had an irregular surface that would allow the solvent to easily permeate. These results illustrate that the physi- cochemical properties of agarose prepared from DMSO extraction and EDTA washing were more effective than those observed after DMSO extraction alone; thus, these processes used in succession will be useful in agarose industries.

Recovery and Fractionation of Serine Protease Inhibitors from Bastard Halibut Paralichthys olivaceus Roe

Protease inhibitors (PI) of trypsin and papain as target proteases from the roe of bastard halibut Paralichthys olivaceus were fractionated out using ammonium sulfate precipitation (A), DEAE 650M anion exchange chromatography (D), and Sephacryl S-300 gel filtration (S). The recovery percentages of the fractions with the strongest inhibitory activity for each fractionation method were 13% for the A4 fraction, 21.2% for the D3 fraction, and 21.3% for the S2 fraction, with specific inhibitory activities of the fractions toward trypsin and casein of 168, 139, and 218 U/mg, respectively, while no inhibition of papain was observed. The for the trypsin-specific substrate -benzoyl--arginine-p-nitroanilide (BAPNA) was 0.65, 1.55, 2.26, and 2.85 mg/mL for the A4, S2, A3, and D3 fractions, respectively. These results suggest that chromatographic fractionation methods (D and S) based on the molecular mass and charge of the protein were more effective at fractionating PI than was ammonium sulfate precipitation based on protein solubility, and that the bastard halibut roe extract acts as a serine protease inhibitor. Therefore, the PI fraction from fish roe might be useful for inhibiting proteases in foodstuffs, and could constitute an alternative food-grade inhibitor for the surimi industry.