Gelatin hydrolysate from blacktip shark skin prepared using papaya latex enzyme: Antioxidant activity and its potential in model systems

Antioxidant activities of gelatin hydrolysates from blacktip shark skin prepared using papaya latex enzyme with different degrees of hydrolysis (DHs: 10%, 20%, 30% and 40%) were evaluated. All antioxidant activity indices of hydrolysates increased with increasing DH (P<0.05). When gelatin hydrolysate with 40%DH was determined for its pH and thermal stability, ORAC and chelating activity remained constant or slightly increased in a wide pH range (1-9) and during heating (100°C) for 240min. It was also stable in simulated gastrointestinal tract model system. Moreover, gelatin hydrolysate at a level of 500 and 1000ppm could inhibit lipid oxidation in both β-carotene linoleate and cooked comminuted pork model systems. Therefore, gelatin hydrolysate from blacktip shark skin (40%DH) can potentially be used as an alternative source of natural antioxidants.     

Protective effects of epigallocatechin gallate (EGCG) derivatives on azoxymethane-induced colonic carcinogenesis in mice

Epigallocatechin gallate (EGCG), the major polyphenol in green tea and a functional food ingredient/nutraceutical with health-promoting properties, was structurally modified by esterification with butyric and docosahexaenoic (DHA) acid in order to improve its lipophilicity and hence bioefficacy in vivo. The lipophilic derivatives of EGCG so-prepared were evaluated for their anticancer activity against azoxymethane (AOM)-induced colon carcinogenesis in mice. Formation of colonic aberrant crypt foci (ACF) was monitored as the biomarker of colorectal cancer (CRC). It was found that oral administration of EGCG derivatives led to reduced size of ACF in the mouse colon. EGCG–DHA esters were more effective than EGCG-butyrate in inhibiting the formation of ACF. The total number of large colonic ACF was remarkably decreased by treatment with EGCG derivatives, especially by the EGCG–DHA esters, which showed a 100% inhibition of large ACF formation. Two tumor-promoting enzymes, iNOS and COX-2 were also inhibited by EGCG derivatives to various extents at the expression level. The results suggest that the lipophilic ester derivatives of EGCG are effective in inhibiting colon carcinogenesis and may be good candidates for colon cancer prevention/treatment.     

Effect of Extraction Temperature on Functional Properties and Antioxidative Activities of Gelatin from Shark Skin

Physico-chemical properties, functional properties, and antioxidative acitivities of gelatin from the skins of brownbanded bamboo shark (BBS; Chiloscyllium punctatum) and blacktip shark (BTS; Carcharhinus limbatus), as affected by extraction temperature, were investigated. ??-Amino acid group content and surface hydrophobicity of both gelatins from both species increased as the extraction temperature increased (P?<?0.05). Both gelatins had a high solubility (more than 80%) in a wide pH range (1?C10). Both gelatins extracted at 60?°C exhibited the highest emulsion activity index (EAI), emulsion stability index (ESI) and foam expansion (FE). The lowest foam stability (FS) was obtained when gelatin was extracted at 75?°C (P?<?0.05). The BBS gelatin had lower EAI, ESI, and FE than did BTS gelatin. Nevertheless, a higher FS was found in the former (P?<?0.05). Antioxidative activities of both gelatins increased with coincidental increase in ??-amino group content as the extraction temperature increased (P?<?0.05). The BTS gelatin generally exhibited the higher antioxidative activities, compared with the BBS gelatin (P?<?0.05). Gelatin extracted at 60?°C showed the highest interfacial properties, while those extracted at higher temperature (75?°C) had enhanced antioxidative activities. Extraction temperature may therefore be regulated to maximize applications.     

Functional Foods: Their Role in Health Promotion and Disease Prevention

ABSTRACT: The effect of food factors on health status has been recognized since antiquity. More recently, epide-miological studies have led to fundamental research for unraveling the chemistry and mechanism of action of dietary phytochemicals and bioactives. Functional foods and natural health products encompass a wide range of food and ingredients, with a variety of bioactives responsible for their efficacy in health promotion and disease prevention. Phenolic and polyphenolic compounds constitute an important class of secondary plant metabolites that act as free radical scavengers and inhibitors of LDL cholesterol oxidation and DNA breakage, among others. Thus, the role of food phenolics and polyphenolics in the prevention of cardiovascular disease and certain types of cancer is well recognized. In addition, certain marine foods have often been considered as "heart food" because of their omega-3 constituents which are known to lower blood triacylglycerol and, possibly, cholesterol levels. Thus, food factors from both plants and animals may be participating in human health promotion.     

Antioxidant activity and water-holding capacity of canola protein hydrolysates

Canola protein hydrolysates were prepared using commercial enzymes, namely Alcalase, an endo-peptidase and Flavourzyme with both endo- and exo-peptidase activities. The hydrolysates so prepared were effective as antioxidants in model systems, mainly by scavenging of free radicals and acting as reducing agents. This effect was concentration-dependent and also influenced by the type of enzyme employed in the process. The hydrolysate prepared using flavourzyme showed the highest antioxidant activity among all samples, whereas the hydrolysates prepared by combination of Alcalase and Flavourzyme did not differ significantly (P > 0.05) in antioxidant effectiveness from that produced by Alcalase alone. The hydrolysates were also found to be effective in enhancing water-holding capacity and cooking yield in a meat model system. Their capability in improving the cooking yield of meat was in the order of Flavourzyme hydrolysates > combination hydrolysates > Alcalase hydrolysates. These results suggest that canola protein hydrolysates can be useful in terms of their functionality and as functional food ingredients and that their composition determines their functional properties and thus their potential application in the food and feed industries.     

Antioxidant and antiviral activities of lipophilic epigallocatechin gallate (EGCG) derivatives

The water soluble green tea polyphenol epigallocatechin gallate (EGCG) was lipophilised by esterification with different fatty acids for expanded applications. Four lipophilic ester derivatives of EGCG, namely EGCG-O-tetrastearate, EGCG-O-tetraeicosapentaenoate, EGCG-O-tetradocosahexaenoate, and EGCG-O-octabutyrate, were prepared and evaluated for their antioxidant and antiviral activities in vitro. Incorporation of fatty acids, especially the long chain polyunsaturated fatty acids (PUFA), into EGCG resulted in increased peroxyl radical scavenging activity, as measured by ORAC (oxygen radical absorbance capacity) assay, and metal chelation capacity. However, the esters exhibited decreased reducing power. Antiviral activities of EGCG derivatives were remarkably higher than the parent EGCG molecule, which showed relatively weak effects. The EGCG–PUFA esters were 1700-fold more effective in inhibiting hepatitis C virus (HCV) protease than the positive control embelin. The derivatives also acted as α-glucosidase inhibitors, suggesting their potential in anti-HIV (human immunodeficiency virus) treatment. The results suggest that ester derivatives of EGCG with improved bioactivities may serve as excellent functional food ingredients and natural health products. Moreover, the omega-3 PUFA in the derivatives may also render additional or synergistic health benefits.     

In-situ synthesis of CuO nanoparticles on cotton fabrics using spark discharge method to fabricate antibacterial textile

In this research, the spark discharge method (SDM) was used for in-situ synthesis of copper and copper oxide nanoparticles (NPs) on cotton fabrics for producing antibacterial textile. Varieties of analytical techniques were applied for the characterization of both NPs and synthesized CuO NPs on cotton fabrics. The structural characterization of the particles was carried out by the X-ray powder diffraction method. Also, the morphological properties of treated cotton samples were investigated using scanning electron microscope. Particle size and size distribution were measured by dynamic light scattering apparatus. The results show that concentration of 100 ppm is enough for killing 10⁶ CFU/mL of bacteria. It is indicated that the synthesized CuO NPs are very strong against both Staphylococcus aureus and Escherichia coli. Also, the durability of antibacterial efficiency after 15 times of washing was tested. The results confirm that the antibacterial fastness properties are significant and no colonies spread over agar plate after 15 cycles of washing. It was concluded that SDM for in-situ synthesize of nano-CuO on cotton fabrics in batch systems is very promising method.     

Antioxidative potential of cashew phenolics in food and biological model systems as affected by roasting

The effect of different roasting conditions on antioxidant capacity of phenolics of cashew nuts and their testa was evaluated using several food and biological model systems. Total phenolic content (TPC) of cashew extracts was determined and accelerated oxidative stability of stripped corn oil in the presence of cashew extracts evaluated. In addition, the antioxidant activity of the extracts was assessed in a β-carotene-linoleate and a cooked comminuted pork model system. Inhibition of oxidation of human low density lipoprotein (LDL) cholesterol and stand breaking of supercoiled deoxyribonucleic acid (DNA) was also investigated. The TPC ranged from 5 to 791 mg gallic acid equivalents/g crude extract. In general, whole cashew nuts and testa extracts demonstrated stronger antioxidant activity than that of the cashew kernel. The inhibition percentage of LDL cholesterol oxidation, as evaluated by conjugated dines formation, of cashew kernels was higher than that of testa and was 69% at the end of 24 h incubation. Extracts of roasted cashew nut showed considerable antioxidative efficiency in model systems employed in this study, however, the effect was not significantly (P ? 0.05) different from that of their raw counterparts, except for the accelerated oxidative stability assay. The results suggest that whole cashew nut and testa extracts could be used as a potential source of natural antioxidants in certain food applications and for disease risk reduction.