Antioxidant and antibacterial activities of natural extracts: application in beef meatballs

The antioxidant and antibacterial effect of rosemary, orange and lemon extracts was investigated in cooked Swedish-style meatballs. Activity in a lard system was established for all the extracts and further determination of the development of rancidity as thiobarbituric acid reactive substances consistently showed that about 50% of the rancidity can be controlled by the citrus preparations. Two of the rosemary extracts (water soluble and oil soluble) were more effective with practically complete elimination of rancidity (TBA values) after a period of 12 days. Rosemary extract activity against lactic acid bacteria and Listeria but not Brochothrix thermosphacta was demonstrated in an agar diffusion test, but in the product only lactic acid bacteria counts were slightly reduced. Sensory analysis results, particularly aroma and acceptability scores, indicated the significant advantages in using rosemary and citrus extracts in rancidity-susceptible meat products.     

Antioxidant activities of squid protein hydrolysates prepared with papain using response surface methodology

Squid protein hydrolysates (SPH) were prepared from the Indian squid Loligo duvauceli using papain. Response surface methodology (RSM) was used for optimization of hydrolysis conditions, including temperature, time, and the enzyme-substrate ratio using DPPH radical scavenging activity as a response. The amino acid composition of SPH was compared with raw squid muscle. In vitro antioxidant activities were evaluated based on reducing power, metal chelation, ABTS, hydroxyl radical, and superoxide anion radical scavenging assays. SPH exhibited good ABTS radical scavenging activities of 96.50±0.90%, superoxide anion radical scavenging activities of 96.4±0.89%, reducing powers of 0.71±0.02, moderate hydroxyl radical scavenging activities of 64.03±2.11%, and metal chelating activities of 52.04±1.02%. In vivo antioxidant activities determined using a sardine minced model system showed 42% reduction in formation of secondary oxidative products as thiobarbituric acid reactive substances (TBARS), almost equivalent to reduction by ascorbic acid of 41.42% at 400 ppm.     

Evaluation of the antioxidant activities and nutritional properties of ten edible plant extracts and their application to fresh ground beef

In this study, we assessed the antioxidant efficacy and nutritional value of 10 leafy edible plants and evaluated their potential as natural antioxidants for meat preservation. We measured total phenolic content, 2,2-diphenyl-1-picryl-hydrazil (DPPH) radical scavenging activity, and vitamin C, chlorophyll, and carotenoid contents of 70% ethanol and water extracts of the edible plants. Based on these results, we investigated the effects of butterbur and broccoli extracts on lipid oxidation in ground beef patties. Plant extracts and butylated hydroxytoluene (BHT) were individually added to patties at both 0.1% and 0.5% (w/w) concentrations. Thiobarbituric acid reactive substance (TBARS) values and color parameters were tested periodically during 12 days of refrigerated storage. TBARS levels were significantly lower (p ≤ 0.05) in the samples containing plant extracts or BHT than the non-treated control. In addition, the beef patties formulated with the selected plant extracts showed significantly (p ≤ 0.05) better color stability than those without antioxidants. These results indicate that edible plant extracts are promising sources of natural antioxidants and can potentially be used as functional preservatives in meat products.     

Antioxidant enzyme activities in beef in relation to oxidation of lipid and myoglobin

Lipid- and oxy-free radical generation has been implicated in oxidative processes which occur during meat maturation but the importance of the antioxidant enzyme (AOE) activity in these processes is not known. It was shown that metmyoglobin (MetMb) % and lipofuscin content were higher in colour-unstable muscles such as psoas major (PM) and diaphragma (D) compared to longissimus lumborum (LL) and tensor fasciae latae (TFL). Although Superoxide dismutase (SOD) activity is higher post mortem in PM and D muscles than in LL and TFL muscles, catalase and glutathione peroxidase (GPx) activities were higher only in D muscle. The higher AOE activity in colour-unstable muscles such as PM and D was not sufficient to prevent increased formation of MetMb and lipofuscin in these muscles compared to LL and TFL muscles.     

Antioxidant activity and properties of gelatin films incorporated with tea polyphenol‐loaded chitosan nanoparticles

BACKGROUND: Gelatin film is widely used for the protection of food quality. In order to improve its antioxidant activity, natural antioxidant tea polyphenol‐loaded chitosan nanoparticles (TPCN) were prepared and incorporated into gelatin film. The antioxidant effect of TPCN against the oxidation of fish oil was investigated, as well as the release of TP from nanoparticles in the film. RESULTS: The incorporation of TPCN greatly decreased the tensile strength and oxygen permeability but increased the water vapour permeability and affected the transparency of gelatin film. Scanning electron microscopy images indicated that extensive interference was embedded with TPCN in the film microstructure. The peroxide value of fish oil packaged with films incorporated with TPCN was lower than that of fish oil packaged with control films during the incubation period. The radical‐scavenging activity of films incorporated with TPCN was higher than that of control films, and increasing radical‐scavenging activity of the former was observed during the storage period. CONCLUSION: The antioxidant activity and properties of gelatin film were affected by TPCN incorporation and storage time. Also, the oxidation of fish oil was retarded. The addition of TPCN could improve the antioxidant activity of gelatin film, and the release of TP from nanoparticles in the film was achieved during the storage period. Copyright © 2009 Society of Chemical Industry     

明胶浸润预处理对挤出吹塑淀粉/明胶可食性复合膜性能的影响

对明胶(gelatin,GEL)进行加水润胀(20%、25%、30%,质量分数)预处理,然后分别与氧化羟丙基淀粉(oxidized hydroxypropyl starch,OS)和羟丙基交联淀粉(hydroxypropyl distarch phosphate,HP)混合,添加起酥油作为疏水剂,硬脂酸锌、硬脂酸钙作为润滑剂,采用挤出吹塑工艺制备了可食性淀粉/明胶复合膜。通过扫描电镜(scanning electron microscope,SEM)、X射线衍射(X-ray diffraction,XRD)、差示量热扫描(differential scanning calorimetry,DSC)、低场核磁共振(low differential scanning calorimetry,L-NMR)、红外光谱(infrared spectroscopy,IR),研究了明胶润胀加水量对复合膜性能与结构的影响。结果表明:25%水润胀的明胶与氧化羟丙基淀粉的复合膜存在最好的相容性,具有最好的力学性能和阻水性。适宜的水分添加量有助于淀粉的糊化和明胶的熔融,有助于增强分子间的作用力和膜的均匀性。     

Antioxidant and functional properties of gelatin hydrolysates obtained from skin of sole and squid

Antioxidant and functional properties were evaluated for gelatin hydrolysates obtained from sole and squid skin gelatin by Alcalase, with a degree of hydrolysis of ∼35% and ∼50%, respectively. Both hydrolysates mainly consisted of peptides below 6.5 kDa, together with peptidic material from around 16 to 6.5 kDa. Moreover, the squid hydrolysate showed a peptide band of around 26 kDa. Antioxidant properties of both gelatins were highly increased by hydrolysis, especially ABTS and metal chelating abilities. The squid hydrolysate showed the highest antioxidant capacity by FRAP, ABTS and metal chelating assays in spite of the lower content in hydrophobic amino acids. Both gelatin hydrolysates had a good solubility (over 95%). The emulsifying activity index (EAI) decreased with increasing concentration. Conversely, the foam expansion increased with increasing concentration. However, both foam and emulsion stabilities were not apparently affected by the concentration of hydrolysate. In the case of the sole hydrolysate, which showed a lower degree Pro and Lys hydroxylation, foam stability was very poor, and 50% of foam expansion was lost after 5 min at all concentrations.     

快速冻融猪皮明胶理化性质分析

对冻融法猪皮明胶的基本理化性质——色差、SDS-PAGE、氨基酸组成、全质构、流体特性、起泡性和泡沫稳定性进行测定。结果表明,冻融法明胶与传统酸法明胶基本理化性质相似,颜色略微深于传统酸法明胶;冻融法明胶质构特性优良,硬度(368. 0 g)显著高于传统酸法明胶(341. 0 g)(P <0. 05);流体特性结果表明冻融法明胶拥有更高的黏度;起泡性研究表明,冻融法明胶溶液质量浓度从10 g/L到30 g/L,其起泡性和泡沫稳定性均优于传统酸法明胶; SDS-PAGE和氨基酸组成结果显示,赋予快速冻融明胶更好功能特性的原因在于,冻融法明胶较传统酸法明胶含有更多高分子亚基组分和更低的小分子组分,以及更高的亚氨基酸含量(252 g/kg)。快速冻融猪皮明胶具有优良的理化加工特性,为明胶的清洁化生产提供了思路。     

Antioxidant activities of fresh grape juices prepared using various household processing methods

The purpose of this study was to evaluate and compare the antioxidant activities, and their contents, in grape juices prepared by various household juicers, and grape flesh (GF). The grape juices were prepared using a low-speed masticating (LSM) juicer, a high-speed centrifugal (HSC) juicer, and a blender (BLD). The total polyphenol, total flavonoid, total monomeric anthocyanin, and vitamin C contents were highest in the LSM grape juice, and decreased in the order: LSM > BLD > HSC > GF. The antioxidant activities such as DPPH radical scavenging activity, and SOD-like activity were significantly higher in the LSM juice than in other juices and grape flesh. The antioxidant activities and the quality of grape juices were significantly affected by the household juicing method used, and an LSM juicer is strongly recommended for making healthy grape juice, rich in antioxidants.     

营养牛肉圆的研制

阐述了营养牛肉圆的制作工艺。采用四因素三水平正交实验法,得出最佳工艺条件为:水35%,淀粉15%,骨泥12%,在85℃的水温下挤丸,保持5～8min即可。这种产品具有良好的风味、色泽、口感,既营养又方便。     

Comparison of physicochemical properties of beef potentiators prepared by synergistic fermentation and traditional method

Beef potentiator was prepared by beef qu, which was previously prepared by a novel synergistic fermentation method (BPSF). Three kinds of other beef potentiators were prepared by commercial enzymes (protamex, flavourzyme and papain, BPCEs), which were used as controls to investigate the physicochemical properties of BPSF. Results showed that BPSF possessed a higher protein recovery (70.99%) and degree of hydrolysis (DH, 51.39%) than BPCEs. The tests of molecular weight distribution and free amino acids (FAAs) indicated that the moderate molecular weight peptides (1–5 kDa) were dominant (70.07–74.43%) in all beef potentiators. The low molecular weight peptides (<1 kDa), umami amino acids and total amino acids in BPSF, were 1.03‐ to 5.56‐, 5.25‐ to 26.50‐ and 1.57‐ to 4.79‐fold higher than those in BPCEs, respectively. Meanwhile, hierarchical cluster analysis indicated that BPSF was significantly different to BPCEs, and sensory evaluation showed that BPSF had apparently stronger umami taste than BPCEs.     

荔枝核提取物抗氧化活性及红外光谱特性

以荔枝核为原料,以95%的乙醇为提取剂,在超声波的作用下得到荔枝核乙醇提取物。利用提取物对DPPH自由基和羟自由基的清除能力评价其抗氧化活性;同时测定了提取物的总还原能力和总的抗氧化性。最后通过红外光谱对提取物进行了定性分析。实验结果表明:荔枝核提取物具有很强的抗氧化活性,其抗氧化能力大于BHT,小于维生素C;荔枝核提取物清除DPPH·和·OH的IC50分别为0.032、0.160mg/mL。每克荔枝核提取物总抗氧化能力相当于210mgVc的总抗氧化能力;从红外光谱的结果可知,荔枝核提取物主要为黄酮类物质。      

冷冻调理土豆牛肉串加工工艺

介绍了调理蔬菜牛肉串的加工工艺,重点讨论生产过程中的一些关键参数,以及这些参数对产品质量的影响。     

Antioxidant nutritional quality of tomato

Regular consumption of tomatoes has been associated with decreased risk of chronic degenerative diseases. Epidemiological findings confirm the observed health effects are due to the presence of different antioxidant molecules such as carotenoids, particularly lycopene, ascorbic acid, vitamin E and phenol compounds, particularly flavonoids. In this work, eight components contributing to the healthy quality of tomato (i. e. lycopene, beta-carotene, other carotenoids, flavonoids, phenolic acids, vitamins C and E, dry residue) were studied in the framework of breeding programs aiming to develop nutritional superior genotypes. Twelve tomato advanced breeding lines and six open pollinated cultivars were grown in strictly controlled conditions and analysed for their content of antioxidants. Among the 18 genotypes analysed, 10 showed a high level of total carotenoids, 6 high level of beta-carotene, 9 high lycopene levels, 15 high flavonoids and 2 relevant concentration of vitamin E. Based on such data and on a literature survey on tomato composition, an index, called index of antioxidant nutritional quality (I(QUAN)), was proposed as a tool to address the breeding programs in selecting tomato genotypes with antioxidant nutritional qualities.     

Antioxidant activities and physicochemical properties of tteokbokki rice cakes containing cinnamon powder

Antioxidant activities and physicochemical properties of tteokbokki rice cakes containing different amounts of cinnamon powder were evaluated. The pH and the L values (chromaticity) decreased, and the moisture content and the a (red) value increased with an increasing cinnamon concentration. The b (yellow) value increased at 1% (w/w) cinnamon powder. The hardness and chewiness increased with an increase in the cinnamon powder content, while the adhesiveness and cohesiveness decreased. The antioxidant effects, total polyphenol content, and DPPH and ABTS radical scavenging activities all increased with an increased cinnamon concentration. Cinnamon can promote expansion of tteokbokki markets, and rice consumption.     

Antioxidant properties of tuna-skin and bovine-hide gelatin films induced by the addition of oregano and rosemary extracts

We have investigated the antioxidant properties (FRAP ferric-reducing ability and ABTS radical-scavenging capacity) as well as the light barrier properties of gelatin-based edible films containing oregano or rosemary aqueous extracts. For comparative purposes both bovine-hide and tuna-skin gelatins were studied. The oregano and rosemary extracts were first characterised by both their total phenolic content and antioxidant activity, with the oregano extract showing the higher values. HPLC and confocal laser scanning microscopy revealed qualitative differences between extracts although rosmarinic acid was the most abundant phenolic compound in both. After determining the total quantities of phenolics on films, the polyphenol–protein interaction was found to be more extensive when tuna-skin gelatin was employed. However, this did not clearly affect the antioxidant properties of the films, although it could affect the phenol diffusion from film to food. The light barrier properties were improved by the addition of oregano or rosemary extracts, irrespective of the type of gelatin employed.     

Antioxidant properties of plum concentrates and powder in precooked roast beef to reduce lipid oxidation

Boneless beef roasts (Semimembranosus + Adductor) were injected (20%) with a brine containing (1) no plum ingredient (control), (2) 2.5 or 5% fresh plum juice concentrate (FP), (3) 2.5 or 5% dried plum juice concentrate (DP), or (4) 2.5 or 5% spray dried plum powder (PP). Whole roasts were cooked, vacuum-packaged and stored at <4.0 °C for 10 wk. At 2 wk intervals, evaluations were performed on sliced product to determine vacuum-packaged purge, Allo-Kramer shear force, lipid oxidation (TBARS), color space values, and sensory attributes. All plum ingredients reduced TBARS values and had minimal effects on tenderness, sensory characteristics, color and appearance. Small changes in purge, color values, TBARS and some sensory properties were found during storage. These results indicate that 2.5% FP or DP could be incorporated into precooked beef roasts to reduce lipid oxidation and potentially, warmed-over flavor (WOF).     

Antioxidant properties of plum concentrates and powder in precooked roast beef to reduce lipid oxidation

Boneless beef roasts (Semimembranosus + Adductor) were injected (20%) with a brine containing (1) no plum ingredient (control), (2) 2.5 or 5% fresh plum juice concentrate (FP), (3) 2.5 or 5% dried plum juice concentrate (DP), or (4) 2.5 or 5% spray dried plum powder (PP). Whole roasts were cooked, vacuum-packaged and stored at <4.0 °C for 10 wk. At 2 wk intervals, evaluations were performed on sliced product to determine vacuum-packaged purge, Allo-Kramer shear force, lipid oxidation (TBARS), color space values, and sensory attributes. All plum ingredients reduced TBARS values and had minimal effects on tenderness, sensory characteristics, color and appearance. Small changes in purge, color values, TBARS and some sensory properties were found during storage. These results indicate that 2.5% FP or DP could be incorporated into precooked beef roasts to reduce lipid oxidation and potentially, warmed-over flavor (WOF).