Color and Oxidative Stability of Nitrite-Free Cured Meat after Gamma Irradiation

The effects of 5 and 10 kGy irradiation on the color and oxidative stability of meats treated with nitrite or a nitrite-free curing system were investigated. The nitrite-free curing system consisted of the preformed cooked cured-meat pigment, sodium ascorbate and sodium tripolyphosphate with or without sodium acid pyrophosphate. Irradiation had no detrimental effects on the color or flavor of either cured samples. Polyphosphates had a beneficial effect on oxidative stability but had a slight detrimental effect on color stability of irradiated samples.     

ANTIOXIDANT ACTIVITIES OF ENZYMATIC EXTRACTS FROM AN EDIBLE SEAWEED SARGASSUM HORNERI USING ESR SPECTROMETRY

The antioxidant activity of water-soluble natural extracts from an edible seaweed , Sargassum horneri, was evaluated by examining the radical scavenging activities of the extracts of hydrolyzates from S. horneri on 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl and alkyl radicals. A spin-trapping electron spin resonance (ESR) spectrophotometer was employed and the results were compared for their ESR signal intensity. The brown seaweed S. horneri was enzymatically hydrolyzed to prepare water-soluble extracts by five carbohydrases (AMG, Celluclast, Termamyl, Ultraflo and Viscozyme) and five proteases (Alcalase, Flavourzyme, Kojizyme, Neutrase, Protamex). The extracts so prepared exhibited strong scavenging activity on DPPH, hydroxyl and alkyl radicals. The scavenging activity of the radicals increased with increased concentration of the extracts. The scavenging results were higher or similar for hydroxyl and alkyl radicals, and lower for DPPH radical compared with vitamin C as a reference. Viscozyme and Alcalase extracts were superior and scavenged radicals examined better than the extracts prepared by other carbohydrases and proteases.     

ANTIOXIDANT ACTIVITY OF WHEAT CARYOPSES AND EMBRYOS EXTRACTS

Phenolic compounds were extracted with 80% methanol from caryopses and embryos of wheat (cv. Alba and Elena). In extracts the content of total phenolics was determined and UV spectra recorded. For all extracts the antioxidant activity in a β-carotene-linoleate model system, scavenging effect on DPPH radical, and reducing power were examined. Extracts of wheat embryos were characterized by a higher content of total phenolics. UV spectra of phenolic compounds extracted from wheat caryopses were characterized by maxima close to 320 nm due to phenolic acids, and by maxima at shorter wavelengths (272–280 nm) attributed to other phenolic compounds. The antioxidant activities of extracts from caryopses in a β-carotene-linoleate model system were higher than those from embryos. The results so obtained were similar to those observed previously for extracts of rye and triticale grains and leguminous seeds. The scavenging effect of wheat extracts on DPPH radical and their reduction power were weak, but those for embryos extracts were somewhat stronger.     

ANTIOXIDANT ACTIVITY OF PHENOLIC FRACTIONS OF LENTIL (LENS CULINARIS)

Extract of lentil seeds in 80% acetone was prepared. Four fractions (I-IV) were separated on a Sephadex LH-20 column using methanol as the mobile phase. The antioxidant activity of each fraction was investigated in a β-carotenelinoleate model system; UV spectra were recorded and the content of total phenolics determined. Results of β-carotene-linoleate model system indicated that antioxidant activities of separated fractions correlated with their content of total phenolic compounds and were in the order of IV>III>II>I. Fractions III and IV from lentil showed much stronger antioxidant activity than phenolics fractions separated from extracts of several different legumes using Sephadex LH-20 column chromatography. Absorption maxima of UV spectra showed that flavonoids were the main phenolic compounds present in the separated fractions. Results of EI-MS confirmed the presence of epicatechin in fraction III while condensed tannins were detected in fraction IV using TLC.     

Effect of Sulfanilamide on the TBA Values of Cured Meats

The effect of sulfanilamide addition on the TBA numbers of meats cured with 0 - 200 ppm levels of sodium nitrite has been investigated. Results indicate that the TBA numbers of meats cured with 100 - 200 ppm level were always larger when sulfanilamide was present than in its absence. However, at low levels of 0 - 50 ppm sodium nitrite the TBA values were always lower in the presence of sulfanilamide. This effect is substantial and has apparently not been observed before. A possible explanation has been put forward. In all cases a distillation method was employed to evaluate TBA numbers.     

Effect of Processing on the Content of Condensed Tannins in Rapeseed Meals

The condensed tannins of rapeseed meals produced by a two-phase solvent extraction system were determined and compared with those of hexane-extracted meals. Ground seeds were extracted with absolute methanol, 95% methanol, 10% (w/w) ammonia in methanol or 10% (w/w) ammonia in 95% methanol and hexane as a second phase. Tannins were extracted with 70% (v/v) aqueous acetone and assayed by the 0.5% vanillin methodology. Methanol alone extracted only 16% of the tannins; addition of 5% (v/v) water to methanol increased the efficiency of tannin extraction to 36%. The methanol-ammonia-water/hexane, however, was the most effective solvent system for the removal of tannins. The resultant meals contained from 4% to 33% of the condensed tannins which were originally present in rapeseed meals.     

ANTIOXIDATIVE ACTIVITY OF PROTEIN HYDROLYSATE FROM ROUND SCAD MUSCLE USING ALCALASE AND FLAVOURZYME

Antioxidative activity of hydrolysates from round scad (Decapterus maruadsi) muscle with degrees of hydrolysis (DH ) of 20, 40 and 60%, prepared using Alcalase (HA) or Flavourzyme (HF), was determined. At the same DH, HF exhibited a higher 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging activity and reducing power, but a lower Fe²⁺ chelating ability than HA. HF from isopropanol‐defatted muscle with 60% DH was extracted using different solvents, and hexane (E1), dichloromethane (E2), ethyl acetate (E3) and residual (R) fractions were obtained. Among all fractions, E2 and E3 exhibited the highest DPPH radical scavenging activity and reducing power. HF with 60% DH and E2 at 1,000 ppm exhibited antioxidant activity in linoleic oxidation and lecithin liposome systems, and the results were comparable to butylated hydroxytoluene (BHT) at 100 ppm. Therefore, type of proteinase, DH and defatting process prior to hydrolysis exerted an influence on the antioxidative activity of hydrolysates.     

LIPID AND LIPID SOLUBLE COMPONENTS OF GONADS OF GREEN SEA URCHIN (STRONGYLOCENTROTUS DROEBACHIENSIS)

Seasonal changes in the lipid and lipid soluble components of gonads of green sea urchin (Strongylocentrotus droebachiensis) were investigated. The lipid content was highest in the spring while it was lowest in the winter. The composition of nonpolar and polar lipid classes of sea urchin gonads were not affected qualitatively, but there were significant (P<0.05) quantitative variations. Major nonpolar lipid classes were triacylglycerols (TAG), free fatty acids (FFA) and sterols (ST) while dominant polar lipid components were phosphatidylcholine (PC) and phosphatidylethanolamine (PE). The fatty acids 16:0 and 14:0 were the major saturated fatty acids (SFA) consistently present in total, nonpolar and polar lipids of sea urchin gonads. The 5-olefinic acid 20:1 n-15 was the dominant monounsaturated fatty acid (MUFA) while 20:4 n-6 and 20:5 n-3 were the major polyunsaturated fatty acids (PUFA) present. The content of PUFA increased during cold climatic conditions with a simultaneous decrease in the content of SFA. These changes were reversed during warm seasons. Total carotenoid content was highest in the spring. Echininone was the major carotenoid present and its relative content varied significantly (P<0.05) with the season; being highest in the spring and lowest in the summer. In addition, β-carotene was present in each season. Thus, the importance of seasonal variations on the lipid and lipid soluble components of sea urchin gonads is evident.