Effect of water activity and temperature on the color change of red pepper (Capsicum annuum L.) powder

Isotherm characteristics of red pepper powder and the effect of temperature and water activity (Aw) on its color change were investigated. Monolayer moisture contents of red pepper powder decreased from 0.1218 to 0.0912 g water/g solid with increasing temperature from 25 to 50°C. The color change of red pepper powder was greatly dependent on temperature and Aw. As temperature and Aw increased, red color of pepper powder increasingly faded out to become brown and tarnish black, which is mainly attributed to the degradation of carotenoid pigments and development of browning compounds. Color parameters such as Hunter-L, a, b values and other color functions as well as browning index and ASTA color values represent color changes of red pepper powder as influenced by temperature and Aw.     

Effects of Shelf-Life Enhancers on E. coli K12 Survival in Solutions Used to Enhance Beef Strip Steaks

ABSTRACT:  The objective of this study was to evaluate the effects of enhancement solutions containing sodium lactate or sodium lactate/sodium diacetate on E. coli K12 transmission to beef strip steaks and in purge. Solutions containing salt, phosphate, and shelf-life enhancers were injected to 10% over initial weight of the steaks. Lactate or lactate/diacetate addition to a solution inoculated with 6 log₁₀ E. coli K12 CFU/mL was equally effective in limiting growth resulting in a 1-2 log₁₀ CFU/g reduction when compared to salt/phosphate in steaks. When inoculation level was 3 log₁₀ CFU/mL in the enhancement solution, microbial growth was detectable only in the purge of steaks enhanced with salt/phosphate only. Lactate increased CIE L* value and b* and decreased a* values when compared to the control. Lactate-/diacetate-containing solutions decreased L* values when compared to lactate alone. Lactate/diacetate also reduced purge loss from steaks compared to lactate and salt/phosphate solutions.     

Assessing Antioxidant Activities of Phenolic Compounds of Common Turkish Food and Drinks on In Vitro Low-Density Lipoprotein Oxidation

ABSTRACT: The total phenol concentrations of solid (9 types of vegetables and 6 types of fruits) and liquid (10 different types of drinks) foods were determined by the Folin-Ciocalteu colorimetric method. Oxidized low-density lipoprotein (LDL) was formed in in vitro conditions, and the effects of the phenolic compound extracts were measured on the inhibition of LDL oxidation. The phenol concentration for the 50% inhibition of LDL oxidation (IC₅₀) and the phenol antioxidant index (PAOXI) were calculated. Walnut (7052 mg/kg) and Turkish coffee (2389 mg/L) had the highest total phenol concentrations. Green pepper and orange nectar had the lowest IC₅₀ values, whereas walnut and red wine had the highest PAOXI values.     

Effect of Iron on the Color of Barley and Other Cereal Porridges

ABSTRACT: Iron added as ferrous sulfate at 500 mg*kg⁻¹ to rice, oats, whole grain wheat, or proanthocyanidin-free barley porridge caused significant changes in the Hunter "L", "a", and "b" values but the visual appearance of these porridges remained satisfactory. Porridge made with normal barley flour fortified with 500 mg*kg⁻¹ of iron developed an unappealing gray color with ferrous sulfate, ferrous fumarate, or electrolytic iron, 3 salts differing in solubility. At 100 and 250 mg*kg⁻¹ of iron, the discoloration of normal barley porridge was less pronounced, but still objectionable. When fortified with 50 mg*kg⁻¹ of iron, normal barley porridge had a slight color change but was not noticeably gray. Thus barley-containing foods can be fortified with a soluble iron compound at the level of iron used in enriched flour and similar cereal-grain foods for the general population without developing an unattractive color.     

The Effectiveness of Sanitizer Treatments in Inactivation of Salmonella spp. from Bell Pepper, Cucumber, and Strawberry

ABSTRACT: Four different postharvest treatments for removal of Salmonella from bell pepper and cucumber were examined, including washes with chlorinated water (HOCl; 200 ppm), acidified sodium chlorite (ASC; 1200 ppm), and peroxyacetic acid (PAA; 75 ppm), and treatment with gaseous chlorine dioxide (ClO₂; total 100 mg). Only ClO₂ gas was evaluated for decontamination of strawberries. Each produce was inoculated with approximately 1.0 × 10⁷ colony-forming units (CFU) of a 5-serovar cocktail of Salmonella on artificially created wounds, smooth surfaces, and stem scar tissue. For tests involving smooth surface inoculation, ASC and PAA treatments decreased contamination to undetectable levels on bell pepper and cucumber, while the chlorine treatment of bell pepper reduced contamination by approximately 2-logs. For stem scar contamination on bell pepper, ASC and PAA treatments both showed >2-log unit reductions, and chlorine treatment showed a <1-log unit reduction. For puncture wounds on bell pepper, HOCl, ASC, and PAA treatments reduced bacterial levels approximately 2-, 3-, and 1-log units, respectively, indicating that HOCl and ASC were more effective than PAA. These aqueous treatments of cucumber with puncture wounds reduced bacterial levels approximately 1-, 2-, and 2-log units, respectively. ClO₂ treatment decreased counts to undetectable levels on all inoculation sites on cucumber and on strawberry smooth surfaces, but failed to completely eliminate Salmonella from bell pepper and from the stem scar and the puncture wounds of strawberry. ASC treatment of bell pepper and ClO₂ gas treatments of cucumber showed the best efficiency for inactivation of Salmonella. ClO₂ treatments effectively reduced Salmonella cells inoculated on the smooth surface and stem scar of strawberries compared with unsanitized control.     

Rapid Colorimetric Determination of Yellow Seed Content in Red Pepper (Capsicum annuum L.) Powder

When the color reflectance of red pepper powders and their yellow seeds were measured using a colorimeter, the mean lightness (L*), redness (a*), and yellowness (b*) values differed considerably between the pepper powders and seeds. On the basis of this difference, we determined the seed content in the red pepper powders by using the correlated reflectance values. As the seed content of the powders increased, both L* and b* increased, while a* decreased. The polynomial regression curve equation, Y( seed content, % ) = 3.51 ×L * - 1.10 ×a * - 1.34 ×b * - 72.74 Y\left( {{\hbox{seed content}},{ }\% } \right) = 3.51 \times L * - 1.10 \times a * - 1.34 \times b * - 72.74 , was obtained from the tristimulus data (L*, a*, and b*) of all the samples used. This is an easy method for the determination of the seed content in red pepper powders and it can be applied to a similar system.     

冷浸渍及单宁处理提升赤霞珠葡萄酒的品质

为研究冷浸渍及单宁处理对赤霞珠葡萄酒颜色稳定性的影响,以和硕产区赤霞珠葡萄酒为对象,通过发酵前赤霞珠葡萄冷浸渍(8℃下,4 d、8 d、12 d)及发酵过程中添加不同浓度的VR单宁(TANIN VR COLOR,0.10、0.20、0.30 g/L)处理,对赤霞珠葡萄酒的基础理化指标、酚类物质以及CIELab颜色参数进行分析。研究发现,冷浸渍处理(4 d、8 d、12 d)与对照组相比总酸含量分别提升了17.63%、15.70%、26.96%,经过不同浓度(0.10、0.20、0.30 g/L)VR单宁处理的葡萄酒总酸含量分别增加了1.33%、16.74%、13.04%;随着冷浸渍时间的延长,葡萄酒中的单宁和总酚的含量有所增加,而花色苷含量在冷浸渍8 d时达到了最大值111.04 mg/L,添加0.20 g/L VR单宁的酒样单宁、总酚及总花色苷含量分别高于对照组28.40%、26.78%、25.42%;冷浸渍8 d的葡萄酒a^*值和Cab值最高,分别为38.85和42.29,而添加了0.20 g/L VR单宁的葡萄酒b^*值和Hab值与对照组相比分别降低了1.61%、1.84%。综合比较表明,冷浸渍8 d和添加0.20 g/L VR单宁的工艺处理可以有效地提升赤霞珠干红葡萄酒的颜色稳定性。     

Changes in carotenoids, ascorbic acids, and quality characteristics by the pickling of paprika (Capsicum annuum l.) cultivated in Korea

Paprika (Capsicum annuum L.) is widely used as a healthy vegetable having antitumor-promoting activity and reducing or preventing chronic disease. Paprika has been mostly consumed as fresh fruit, and as food colorants such as oleoresin or pigment powder. In this study, pickled paprika was produced and its quality characteristics were monitored during storage (35 °C for 42 d). Carotenoid composition, ascorbic acid, total phenolic contents, and antioxidant activities were also analyzed. Five carotenoid compounds were identified in the pickled paprika and after 42 d of storage, total carotenoid content was 2.44 ± 0.69 mg/100g fresh weight(fw) and ascorbic acid content was 50.90 ± 3.26 mg/100g dry weight (dw). 2,2'-azino-di-(3-ethylbenzthiazoline sulphonate (ABTS) radical-scavenging activity of the pickled paprika was maintained above 70% until 28 d of storage, and then decreased to 47% of the initial activity. pH increased from 2.78 ± 0.06 to 3.10 ± 0.03 at 14 d and was then maintained until 42 d. Soluble solids increased gradually and color values including L*, a*, and b* decreased during storage. Hardness also decreased from 6.17 ± 0.18 kg force to 1.90 ± 0.60 kg force during storage. The overall taste of the pickled paprika was deemed to be good until 28 d of storage. Pickled paprika showed a possibility as a new pickled product. We demonstrated that paprika could be processed as a new pickled product with extended storage. PRACTICAL APPLICATION: Pickled paprika was produced and its quality characteristics along with phytochemical contents were monitored during storage. Phytochemicals, including ascorbic acid and polyphenols in pickled paprika were considerably retained and visual color was satisfactory during storage. Texture was deemed to be satisfactory for 4 wk. Considering that our experiment was performed at a relatively high temperature and without the addition of calcium for the improvement of texture, our results are quite promising in order to produce new pickled products with extended shelf-life along with conserving nutritional and functional components and satisfying consumer needs.     

1-MCP结合二氧化氯处理对青椒货架期品质的影响

为研究青椒货架期品质保鲜新技术,延长货架期,于室温(25±1)℃贮藏条件下,分别用1-MCP(1 mg/L)、1-MCP(1 mg/L)和ClO₂(30 mg/L)联用对青椒进行熏蒸处理,定期测定相关的指标,包括腐烂率、转红率、硬度、失重率、V_C含量、叶绿素含量、还原糖含量等。结果发现:1-MCP单独处理以及1-MCP结合ClO₂处理在青椒贮藏保鲜过程中均起到良好的效果,但1-MCP结合ClO₂处理比1-MCP单独处理更能有效保持青椒贮藏过程中的品质,抑制青椒的腐烂、失重和转红,延缓叶绿素的降解速率。货架期结束时,对照组中腐烂率是1-MCP+ClO₂处理组(3.33%)的5倍;V_C含量、还原糖和叶绿素含量分别高于对照27.40%、44.31%、20%。在整个贮藏期间,1-MCP结合ClO₂处理的果实硬度仅下降了6.70%。结果表明,1-MCP结合ClO₂处理可以有效延缓青椒的采后生理变化,保持青椒的品质。     

Carbon monoxide treatments to impart and retain muscle color in tilapia fillets

ABSTRACT:  Carbon monoxide (CO) has been used for improving the color of muscle foods. In the current study, we compared the postmortem treatment of tilapia fillets with 100% CO and euthanasia of live tilapia with CO for their ability to stabilize the color of white and red muscle of tilapia fillets. Both postmortem CO treatment and CO euthanasia were effective in increasing the redness ( a * value) and lightness ( L * value) of tilapia white and red muscle. Fillets obtained from CO-euthanized tilapia showed significantly higher a * and L * values during 1 mo of frozen storage at –20 °C and subsequent thawing and storage at 4 °C for 18 d. The amount of CO present in the red and white muscles decreased during the 18 d of storage at 4 °C. There was no significant difference in the pH, drip, or thaw loss of CO-treated tilapia fillets compared to the untreated fillets.     

Influence of exposure to light on the sensorial quality of minimally processed cauliflower

ABSTRACT:  The impact of lighting on minimally processed cauliflower packaged in 4 different film types (PVC and 3 P-Plus) has been measured and quantified. The effect on the sensorial quality of storage at 4 °C in darkness and partial or continuous lighting was evaluated. The gas concentrations in the packages and the weight losses were also determined. Atmosphere composition inside the packages depended on both the permeability of the film used for the packaging and exposure to light. Samples stored with lighting maintained the gaseous exchange between plant tissue and the atmosphere inside the packages for longer periods than in samples kept in darkness. This prompted a greater loss of water vapor as well as the development of atmospheres with low levels of O₂ and high levels of CO₂ in the samples packed with less permeable films. The most important aspect in sensory evaluation was color. In instrumental color evaluation, coordinates h * and L * were the main means for estimating color evolution. The presence of light accelerated browning in the cut zones. The development of abnormal coloring in these areas marked the end of shelf life for minimally processed cauliflower. Among the sensory attributes studied, color was the most affected by exposure to light. Samples packed in P-Plus 120 film displayed the lowest level of color deterioration in the cut zones. However, under lit conditions, the low permeability of this film caused atmospheres with very low O₂ contents and high CO₂ contents. These atmospheres produced a loss of texture and the development of off-odors.     

不同包装材料对娃娃菜贮藏过程中品质指标的影响

以娃娃菜(Brassica campestris)为包装对象,采用聚乙烯包装袋、聚氯乙烯包装袋、防雾包装袋、纳米包装袋这四种包装材料对新鲜的娃娃菜进行低温(4℃)和常温(20℃)下的保鲜贮藏。通过测定低温和常温贮藏期间娃娃菜的质量损失率、颜色(L*、a*、b*值)、叶绿素、V_C、硬度等指标,研究其对娃娃菜贮藏期间品质和生理变化的影响,并筛选出最佳包装材料。结果表明:四种包装材料对娃娃菜均具有良好的保鲜作用,主要表现在降低质量损失率,保持色泽,维持硬度,有效抑制V_C和叶绿素含量的降低,从而延缓衰老和褐变。其中,纳米包装的效果较优于其他三种包装材料,在(20±0.5)℃条件下,贮藏15 d时,纳米包装组的质量损失率为0.59%,而对照组达到55.8%,差异显著(P<0.05),L*值、a*值和b*值均高于对照组。其中硬度维持在20.0 N,而对照组硬度由贮藏初期的26 N下降至12.1 N,差异显著(P<0.05)。V_C和叶绿素的含量至贮藏期结束分别为45.0 mg/g和0.025 mg/g,均显著高于对照组(P<0.05)。娃娃菜在(4±0.5)℃、相对湿度85%~95%的贮藏环境下贮藏,和常温结果相似,纳米包装袋组的结果明显优于对照组,贮藏30 d后仍具有商品价值。     

Quality changes in beef gluteus medius, infraspinatus, psoas major, rectus femoris, and teres major enhanced prior to aging

ABSTRACT:  The objective of this study was to evaluate the effects of enhancement and aging on quality characteristics of the gluteus medius (round), rectus femoris (round), teres major (chuck), infraspinatus (chuck), and psoas major (loin). Muscles were enhanced, vacuum packaged, and aged for 7 or 14 d. Aging affected enhanced compared with nonenhanced beef differently. After 7 d of aging, enhanced beef experienced more cook loss and was less red (higher hue angle, lower a * values, and chroma) than did nonenhanced beef; after 14 d of aging, these differences were lost. Enhancement increased tenderness and brown color of the gluteus medius (round); however, it decreased visual green and red colors. Enhanced gluteus medius experienced 3.1% lower purge losses, lower L * values, and chroma than their nonenhanced counterparts. Enhancement increased infraspinatus (chuck) tenderness and visual brown color, and decreased visual red and green colors, purge loss, L * value, a * value, and chroma. The enhanced infraspinatus was substantially more tender than the other muscles evaluated, other than the gluteus medius ; however, it was also substantially more visually brown. Enhancement decreased purge loss of the psoas major . Enhancement increased L * and a * values, hue angles, and chroma than other enhanced muscles. After enhancement the tenderness of the rectus femoris increased by 10%, decreased purge losses from 4.5% to 1.7%, and decreased green color by 18%. It reduced L * and a * values and chroma. Aging increased tenderness. Overall, muscles from the chuck ( infraspinatus and teres major ) appeared to benefit the most from enhancement.     

Evaluation of the Ability of Eleutherine americana Crude Extract as Natural Food Additive in Cooked Pork

ABSTRACT:  The scavenging activities of crude ethanolic extract from  Eleutherine americana , on 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl free radicals were investigated. The results revealed that the extract produced IC₅₀ values of 8.4 μg/mL and 0.78 mg/mL on DPPH and hydroxyl free radicals, respectively. The total phenolic content of the extract was determined using the Folin–Ciocalteu reagent and the crude extract yielded high phenolic content of 4.56 μmol gallic acid equivalent per milligram dried extract. The extract, at different concentrations, was incorporated into pork, cooked in the microwave, and stored at 4 °C for 9 d. The crude extract demonstrated antioxidant activity, which increases with increased extract concentrations and retarded lipid oxidation in the cooked pork. Antibacterial activity of the extract against  Staphylococcus aureus  in the cooked pork revealed that at a concentration of 10.8 mg/100 g, the extract reduced the bacterial population by 0.57 log compared to control at 9 d of storage. The sensory results revealed that the pork samples treated with the extract and the control sample were not significantly different from day 0 to 6; however, on day 9 the treatments were significantly scored higher than the control. Furthermore, addition of the extract led to an increase in the redness values of the pork and this was acceptable from the sensory point of view.  E. americana  crude extract could be a promising novel antioxidant to prevent lipid oxidation and a potential natural color enhancer of red meat and meat products.     

Influence of source and quality on the color characteristics of annatto dyes and formulations

Annatto dyes containing different strengths of bixin, norbixin and their formulations such as water-soluble liquid, and oil soluble liquid were measured for L*, a* and b* in a Hunter color meter and the Yellow (Y) and red (R) units in a Lovibond tintometer. Seed source and dye purity had a significant effect (P < 0.05) on the color characteristics L*, a*, b* and Y and R units of bixin/norbixin dyes and their formulations. These characteristics behaved independently when different dyes diluted to a common concentration of 50 mg bixin or norbixin/L. However, when individual bixin/norbixin dyes serially diluted L*, b* decreased and a* values increased with increase in concentration of bixin/norbixin. Similarly the increase in concentration of bixin/norbixin have shown decreasing trend on Y/R values due to increase in R-values in the tintometer. It has been observed that a* and R units generally increased with increase in concentration, and L* and b* values decreased and Y values are almost constant in both the bixin and norbixin dyes. However the b*/a* values showed lower values in bixin dyes and higher in norbixin dyes. Similarly R-values were higher in bixin dyes when compared to norbixin dyes.     

Effect of Capsicum annuum (Red Sweet and Cayenne) and Piper nigrum (Black and White) Pepper Powders on the Shelf Life of Fresh Pork Sausages Packaged in Modified Atmosphere

ABSTRACT Capsicum annuum (red sweet and hot cayenne) and Piper nigrum (black and white) pepper powders were evaluated for inhibition of oxidative reactions and extension of the shelf life of fresh pork sausages packaged in a modified atmosphere. Sausages containing either red sweet pepper or cayenne pepper (0.1%, 0.5%, or 2%) or black or white pepper (0.1%, 0.5%, or 1%) were packaged in a modified atmosphere of 80% O₂+ 20% CO₂, stored for 16 d in the dark at 2 °C, and analyzed each 4 d for pH, CIE L*, a*, and b*, 2‐thiobarbituric acid‐reactive substances (TBARS), psychrotrophic aerobes, sensory discoloration, and off‐odor. Results demonstrated that Capsicum peppers (sweet red and hot cayenne) enhanced red color but failed to prevent discoloration, whereas they were very effective in inhibiting lipid oxidation, chiefly at the highest concentration used (2%), which resulted in a delay of off‐odor formation. Piper peppers (black and white) significantly delayed discoloration with small modification of sausage color; furthermore, they also inhibited lipid oxidation, which led to a delay of off‐odor formation, particularly in the form of black pepper. Besides this, all those spices inhibited microbial growth when added at the highest concentration (1%Piper and 2%Capsicum).     

Spoilage of Rested Harvested King Salmon (Oncorhynchus tshawytscha)

ABSTRACT Laboratory-reared king salmon were harvested using CO₂ anesthetizing (CO₂) or by rested harvesting techniques using AQUI-S(tm) anesthetizing (AQUI-S). Fish were killed by spiking, and flesh portions were stored in air packs (0°C) for 22 d. Headspace oxygen levels, sensory characteristics (raw and cooked), tensile properties, drip loss, gaping, pH, nucleotide derivatives, color, and bacterial counts were determined after 5 to 22 d of storage. All parameters except tensile properties showed significant trends with storage time. Oxygen levels were consistently lower in CO₂ packs whereas, on average, drip was lower in AQUI-S samples, and L*-values and bacterial numbers were higher in AQUI-S samples. Overall, harvesting effects had minimal impact on the quality parameters measured.     

The Effects of Residual Oxygen on the Storage Life of Retail-Ready Fresh Beef Steaks Masterpackaged Under a CO2 Atmosphere

ABSTRACT:  Retail-packed rump ( Gluteus medius , GM) and striploins ( Longissiumus dorsi, LD) steaks were masterpackaged under carbon dioxide (CO₂) and stored at 1 °C ± 1 °C for 14, 28, 35, and 42 d. A commercial oxygen (O₂) scavenger (ATCO HV1000®, Standa Industrie, Caen, France) was used in the masterpacks to achieve an O₂-free atmosphere. Similar packages without the O₂ scavengers were also prepared. At each storage time, 2 masterpacks of each treatment were opened and the retail trays were placed in a display case at 4 °C ± 2 °C for 1 and 48 h for microbiological and sensorial evaluations. The low growth rate of aerobic psychrotrophic flora on the stored beefsteaks demonstrated the bacteriostatic effect of CO₂ during storage. The maximum level of psychrotrophic aerobic bacteria reached during storage was approximately 10⁶ CFU/g. The steaks stored in masterpacks with scavengers bloomed to the desirable red color associated with freshly cut meat in the display case for all of the storage periods, except in the case of GM steaks, which showed a cycle of transient discoloration. GM and LD steaks were well accepted (65% and 82%, respectively) after 42 d under CO₂ at 1 °C ± 1 °C. The GM and LD steaks stored without the O₂ scavenger showed variable fractions of discoloration that significantly detracted from the appearance of the samples.     

不同预冷温度对鲈鱼冰藏期间质构和色差的影响

以鲜活鲈鱼为对象,将其置于不同水温(15、10、5℃)中暂养0.5 h后,在冰藏条件下贮藏,分别在第0、3、6、9、12、15、18、21 d对鲈鱼的质构特性和色差进行测定,综合评价不同预冷温度对鲈鱼冰藏期间质构和色差的影响。研究结果表明,冰藏过程中,不同预冷温度下鲈鱼的硬度均随贮藏时间的延长呈小幅度降低(p<0.05);而内聚性和弹性的变化趋势并不明显,未呈现显著的规律性变化,只在小范围内上下波动(p>0.05),各处理组组间差异不显著(p>0.05)。可见,不同预冷温度对鲈鱼冰藏过程中鱼肉的质构特性影响不大。在不同预冷温度下,对照组和预冷组的鲈鱼在冰藏期间的亮度值和红度值均随贮藏时间的延长呈下降的趋势,黄度值呈缓慢上升趋势,总色差出现不同程度的上升。15℃预冷处理能延缓鲈鱼冰藏时色泽变化,可以较好保持鱼肉的亮度值和红度值。     

黑果腺肋花楸花色苷的提取工艺优化及其稳定性

以黑果腺肋花楸果实作为原料,采用单因素实验及正交法优化花色苷提取条件,并测定在不同条件下对花色苷稳定性的影响。结果表明:乙醇浓度50%,液料比25:1 g/mL,提取温度55 ℃,提取时间60 min为最佳提取条件,此时黑果腺肋花楸花色苷提取量可达到(4.32±0.18) mg/g。当pH≤3时,花色苷呈红色且稳定性较强;随着温度升高和光照时间增加,花色苷极其不稳定,溶液颜色逐渐变浅;随着H₂O₂和Na₂SO₃浓度逐渐增加,花色苷溶液逐渐褪色。黑果腺肋花楸花色苷在酸性条件下比较稳定,且在加工运输保存时应尽量避免接触氧化剂和还原剂。