Restructured Reindeer Steak Quality as Affected by Antioxidants and Frozen Storage

Restructured steaks were fabricated from forequarter muscles from field-slaughtered Alaskan reindeer. Steaks were formulated with an antioxidant (1:1 mixture of BHA and TBHQ with a propylene glycol carrier) at 0.00, 0.01 and 0.02% of the fat and 0.5% salt. Steaks were flash-frozen, vacuum-packaged and stored at ?18°C. Instrumental and sensory testing was conducted after storage (2, 6, 10, 14, 18, 22 wk). Minimal effects occurred on moistness, greasiness, softness and chewiness. Gamy flavor intensity decreased and off-flavor intensity fluctuated with storage and antioxidant. Effects of antioxidants on color were not notable. Use of the antioxidant system is not justified by any oxidative or color effects. Frozen storage was not detrimental to restructured steak quality.     

Antimicrobial and antioxidant activities of different propolis samples from north‐western Algeria

The aim of this study was the investigation of antimicrobial and antioxidant activities of different ethanolic extracts of propolis (EEP) collected from north‐western Algeria. Total polyphenols and flavonoids contents of extracts were measured. The UV absorption spectrum showed and confirmed their polyphenols constituents. All EEPs exerted antibacterial activity against Gram‐positive bacteria, but no effect on Gram‐negative bacteria. The minimum inhibitory concentration (MIC) of EEPs ranged from 0.01% to 2.6% v/v. The antioxidant activity was measured using ferric‐reducing power (FRAP), 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) free radical‐scavenging and ESR methods. Propolis TIA‐2 and MOH‐MAS samples showed the highest antioxidative capacity, after 35 min, while TIA‐1, NED‐TL and SFS‐SBA samples showed the highest antioxidative potential of measured EEPs, after 3 min. TIA‐2 sample showed the highest antibacterial, antioxidant activity and highest DPPH free radical‐scavenging activity as well as the highest polyphenols and flavonoids content, compared with other propolis samples.     

不同抗氧化剂对米糠油抗氧化性能影响的研究

试验研究了在(63±1)℃加速氧化条件下,以过氧化值(POV)作为评价指标,TBHQ、BHT、PG、柠檬酸及复配抗氧化剂对米糠油抗氧化性能的影响.结果表明,复配氧化剂的抗氧化效果优于单一抗氧化剂,柠檬酸对酶抗氧化剂有协同增效作用,精制米糠油中添加0.015%TBHQ+0.005%PG和0.01%柠檬酸的抗氧化效果最好,是不加抗氧化剂的米糠油的抗氧化效果的9倍.     

Utilization of adzuki bean extract as a natural antioxidant in cured and uncured cooked pork sausages

A commercial adzuki bean extract (AE) was evaluated for antioxidant effectiveness in cured and uncured cooked pork sausages. TBARS values, instrumental color evaluation and sensory panel scores were assessed. For uncured sausages, AE at 0.2% was equally effective as 0.1% butylated hydroxytoluene (BHT) in reducing TBARS values. Similarly, AE at 0.2% significantly (P<0.01) reduced the TBARS in cured sausages. Incorporation of 0.2% AE into sausages produced higher (P<0.05) CIE lab color a* value and lower (P<0.05) L* and b* values. Sensory panels did not detect any difference in color, odor, taste, flavor, and overall acceptance in uncured pork sausages with addition of 0.2% AE. However, there were adverse changes in the color and odor of cured sausages, even though the taste, flavor, and overall acceptance were similar. Therefore, the results suggest that AE is a potential antioxidant.     

Impact of enzyme inactivation conditions during the generation of whey protein hydrolysates on their physicochemical and bioactive properties

The thermal inactivation conditions (75 °C × 35 min, 80 °C × 10 min, 85 °C × 5 min and 90 °C × 5 min) for Protamex? following bovine whey protein concentrate (WPC) hydrolysis was studied with the view to limiting WPC hydrolysate (WPH) aggregation while maintaining bioactivity. A decrease in the amount of large WPH aggregates formed was observed at inactivation temperatures ≤85 °C. However, the WPC appeared to be more hydrolysed on heating at 75 °C × 35 min, as Protamex? was active for longer under these heating conditions. Significantly (P < 0.05), higher WPH antioxidant (oxygen radical absorbance capacity – ORAC) activity was obtained on inactivation at temperatures ≤80 °C. In contrast, the dipeptidyl peptidase IV (DPP‐IV) inhibitory properties of all WPH samples were similar (P > 0.05). A reduction in thermal treatment from 90 °C × 5 min to 85 °C × 5 min was sufficient to decrease the amount of large aggregates formed in the hydrolysate without altering its bioactive properties.     

Culinary herbs inhibit lipid oxidation in raw and cooked minced meat patties during storage

The effect of dried spices and the ethanol extract of those spices was studied on the stability of fresh chicken minced meat, and fresh and cooked pork patties pretreated with NaCl during refrigerated and frozen storage. The antioxidant activities of the spices were measured by thiobarbituric acid reactive substances (TBARS) and peroxide value (POV) in meat samples. The lipid oxidation was effectively inhibited in the chicken meat treated with several dry spices diminishing the TBARS to a range of 32% and 83% of those found in the control samples in frozen stored meat for 6 months. Marjoram, wild marjoram and caraway were the most effective dry spices. Ethanolic extracts of the same spices were more potent as antioxidants by lowering the concentration of the TBARS to a range of 20–27% of those found in the control samples. Addition of sodium salt to the minced pork resulted very high concentrations of the oxidation products originated from the polyunsaturated fatty acids. The treatment with ethanolic extract of spices (sage, basil, thyme and ginger) significantly inhibited the lipid peroxidation in refrigerated and chilled pork patties pretreated with NaCl by reducing both POV and TBARS. Heat treatment with microwaves produced significantly elevated levels of both lipid peroxides and TBARS, but the amount of these oxidation products was less than 10% in spice‐treated salted meat samples compared to that in untreated ones. Lipid peroxidation also grew continuously during the storage period at −18°C in raw and cooked samples. Ethanolic extracts of spices had a very strong antioxidative effect inhibiting lipid peroxidation in heat‐treated meat products during frozen storage. The highest antioxidant activity was observed in the case of ginger. High correlation coefficients were found between TBARS and POV both in raw and cooked pork patties (0.86, 0.91, respectively) during frozen storage. It is supposed that these compounds originated from the polyunsaturated fatty acids during oxidation processes but at different stages. Utilization of spices, spice mixtures or spice extracts in semi‐prepared meat products intended to be frozen for up to 6 months or more before consumption is proved to be advantageous in regard of shelf life of the food, as well as of human health, because of the beneficial effect of spices in inhibition of lipid peroxidation during heat treatment and chilling storage. © 1999 Society of Chemical Industry     

Characterization of Enzyme Released Antioxidant Phenolic Acids and Xylooligosaccharides from Different Graminaceae or Poaceae Members

Xylooligosacchrides (XOS) and phenolic acids were simultaneously produced from hemicelluloses using crude enzyme mixture synthesized by a novel Bacillus subtilis KCX006. The strain synthesized XOS-forming endo-xylanase and de-branching α-L-arabinofuranosidase and esterase but not β-xylosidase. This enzyme mixture can improve the yield of XOS and phenolic acids from xylan due to the absence of hydrolysis of XOS by β-xylosidase and release of phenolic acids by esterase. Hence, the enzyme mixture was tested for simultaneous production of XOS and phenolic acids from xylan (28–35%)-rich Graminaceae or Poaceae plant biomass, such as wheat bran, sugarcane bagasse, bamboo, and rise husk. Hemicellulose fractions of the biomasses were extracted by alkaline treatment and hydrolyzed using crude xylanase mixture. The profiles of XOS and phenolic acids formed were analyzed by HPLC. The lyophilized hydrolytic products were further analysed by ¹H NMR to identify the substitutions in XOS. The observed profile of XOS and phenolic acids varied with the biomass sources. Maximum amounts of XOS (665.2 mg/g dwt) and phenolic acids (89.69 μg/g dwt) were produced from hemicellulose A fractions of sugarcane bagasse and bamboo bagasse, respectively. HPLC and ¹H NMR analysis of XOS revealed the formation of free- and arabino-XOS. Phenolic acids consisted of hydroxycinnamic and hydroxybenzoic acids and the antioxidant activity correlated well with hydroxycinnamic acids content. The crude enzyme of B. subtilis is useful to produce mixture of XOS and phenolic acids from biomass.     

不同温度下高压处理牛肉TBARS值的变化及抗氧化剂和螯合剂的抑制作用研究

对不同温度(20℃、40℃和60℃)下压力(从200～800MPa)处理20min以及在4℃下贮藏7d后牛肉脂肪TBARS值的变化进行了研究。结果显示:常压下肌肉的TBARS值随热处理温度的升高而增加;同样,室温下压力的增加导致脂肪氧化程度的加剧,尤其是在400MPa及其以上压力;40℃和60℃下的压力处理,TBARS值的变化规律与室温下极为相似。添加1%的Na2EDTA可有效地降低肌肉不同温度(20～60℃)下200MPa和600MPa压力处理和贮藏后的TBARS值,阻止压力和热处理导致的脂肪氧化,此结果表明热和压力处理的肌肉中蛋白质结构的破坏和过渡金属离子的释放是造成脂肪氧化的主要原因。VE和BHT也具有良好的抗氧化作用,0.05%的VE和0.02%BHT结合使用,比单独的VE具有更好的抗氧化效果。     

Utilization of natural antioxidants: Green tea extract and Thymbra spicata oil in Turkish dry-fermented sausage

Effect of natural (green tea extract, Thymbra spicata oil) and synthetic antioxidants (buthylatedhydroxytoluene, BHT) on the safety (biogenic amine and TBARS values) and quality (pH, colour and sensory attributes) of sucuk (Turkish dry-fermented sausage) were investigated during the ripening periods. Addition of antioxidants decreased (P<0.05) the TBARS values. It was found that natural antioxidants decreased TBARS formation more than BHT. Antioxidants reduced (P<0.05) putrescine formation in the following order: green tea extract>green tea extract-T. spicata oil>T. spicata oil>BHT, and their mean values were 70.45, 76.05, 83.13, and 95.97mg/kg, respectively. The highest tyramine concentration was observed in control sucuk prepared without any antioxidants, while the lowest was in the recipe with green tea extract as their mean values were about 99.42 and 64.31mg/kg, respectively. The pH, L, b, and overall sensory quality were not significantly different (P>0.05) with the addition of green tea extract, T. spicata oil, green tea extract-T. spicata oil. These results indicated that the most effective antioxidant was found to be green tea extract. This study pointed out that natural antioxidants were more effective than synthetic antioxidants, so they could be easily utilized in sucuk to enhance quality and provide safer products.     

Effect of natural and synthetic antioxidants on protein oxidation and colour and texture changes in refrigerated stored porcine liver pâté

The antioxidant effect of two plant essential oils (sage and rosemary) and one synthetic antioxidant (BHT) on refrigerated stored porcine liver paté (4°C/90 days) was evaluated. Patés with no added antioxidants were used as controls. Liver patés were analysed for protein oxidation, modification of heme (HI) and non-heme iron (NHI) concentrations, and colour and texture characteristics at days 0, 30, 60 and 90 of refrigerated storage. The amount of carbonyls from protein oxidation significantly (p<0.05) increased during refrigerated storage, and this increase was significantly higher in the control patés than in their treated counterparts. Antioxidants successfully protected heme molecules from degradation and significantly inhibited the increase of NHI in refrigerated stored liver patés. Colour changes seemed not to be directly related to oxidative processes since patés with added antioxidants suffered greater colour modifications than the controls. The addition of rosemary essential oil significantly reduced hardness of liver patés. Sage and rosemary essential oils exhibited similar antioxidant properties to BHT denoting their suitability as alternatives to synthetic antioxidants.