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1.
Nazmi İzli Gökçen Yıldız Halil Ünal Eşref Işık Vildan Uylaşer 《International Journal of Food Science & Technology》2014,49(1):9-17
In this study, the effects of convective, microwave and microwave–convective drying methods on the drying characteristics, colour, total phenolic content and antioxidant capacity of goldenberry fruits were investigated. To select the most appropriate thin‐layer drying model for drying treatments, nine mathematical drying models were fitted to the experimental data. Based on the statistical tests used for evaluation, the Midilli et al. and Wang and Singh models were considered the best models to describe the drying behaviours of goldenberry fruits in all drying methods. The colour values (L*, a* and b*) of fresh fruit were decreased by drying. Compared with the fresh sample, the dried samples exhibited a 64–75% and 65–75% decrease in total phenolic content and antioxidant capacity, respectively. Among the different drying treatments, the values closest to those of fresh samples with respect to colour values, total phenolic content and antioxidant capacity were achieved with the 160 W microwave drying method. 相似文献
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The objective of this study was to improve product quality of dehydrated fruits (apple, pear, papaya, mango) using combined drying techniques. This involved investigation of bioactivity, colour, and sensory assessment on colour of the dried products as well as the retention of the bio-active ingredients. The attributes of quality were compared in regard to the quality of dehydrated samples obtained from continuous heat pump (HP) drying technique. It was found that for apple, pear and mango the total colour change (ΔE) of samples dried using continuous heat pump (HP) or heat pump vacuum-microwave (HP/VM) methods was lower than of samples dried by other combined methods. However, for papaya, the lowest colour change exhibited by samples dried using hot air–cold air (HHC) method and the highest colour change was found for heat pump (HP) dehydrated samples. Sensory evaluation revealed that dehydrated pear with higher total colour change (ΔE) is more desirable because of its golden yellow appearance. In most cases the highest phenol content was found from fruits dried by HP/VM method. Judging from the quality findings on two important areas namely colour and bioactivity, it was found that combined drying method consisted of HP pre-drying followed by VM finish drying gave the best results for most dehydrated fruits studied in this work as the fruits contain first group of polyphenol compounds, which preferably requires low temperature followed by rapid drying strategy. 相似文献
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Evaluation of antioxidant capacity and total phenolic content of different fractions of selected microalgae 总被引:1,自引:0,他引:1
Hua-Bin Li Ka-Wing Cheng Chi-Chun Wong King-Wai Fan Feng Chen Yue Jiang 《Food chemistry》2007,102(3):771-776
In order to identify new sources of safe and inexpensive antioxidants, the antioxidant capacity and total phenolic content of different fractions of 23 microalgae were evaluated, using Trolox equivalent antioxidant capacity assay and the Folin–Ciocalteu method, respectively. The microalgae were extracted using hexane, ethyl acetate and water by a three-step sequential extraction procedure. Most of these microalgae were evaluated for the first time for their antioxidant activities. It was found that the microalgae Synechococcus sp. FACHB 283, Chlamydomonas nivalis and Nostoc ellipsosporum CCAP 1453/17 possessed the highest antioxidant capacities and thus could be potential rich sources of natural antioxidants. In addition, the correlation coefficients between the antioxidant capacities and the phenolic contents were very small in hexane (R2 = 0.0075), ethyl acetate (R2 = 0.5851) and water (R2 = 0.3599) fractions. Thus, phenolic compounds were not a major contributor to the antioxidant capacities of these microalgae. This was very different from many other plant species like fruits, vegetables and medicinal plants. The microalgae could contain different antioxidant compounds from other plants. 相似文献
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以3种不同的青稞为原料,采用不同的提取溶剂(水、60%乙醇、60%甲醇、60%丙酮、95%乙醇、100%甲醇、100%丙酮)对青稞进行提取。对各提取物的总酚、总黄酮进行测定,同时采用3种抗氧化方法:二苯代苦味酰自由基(DPPH)、2,2’-联氨-双(3-乙基苯并噻唑啉-6-磺酸)二胺盐自由基(ABTS)和总抗氧化能力(FARP)评价青稞提取物的抗氧化活性。结果表明,95%乙醇和60%丙酮更有利于青稞多酚的提取。藏青2000的各溶剂提取物的总酚、总黄酮及抗氧化活性普遍高于相应溶剂的循化蓝青稞和香格里拉绿青稞。藏青2000的60%丙酮提取物含有最高的总酚含量,达到211.92mg GAE/100g DW;在60%乙醇提取时具有最高的总黄酮含量,达到60.11mg RT/100g DW;在60%乙醇提取时具有最强的DPPH清除能力,达到80.08%;而用60%丙酮提取时,具有最强的ABTS清除能力和总抗氧化能力,分别达到了1.85,9.28 mmol TEAC/100g DW。总酚含量与抗氧化活性均具有显著的相关性,FRAP法与DPPH、ABTS法具有极显著的相关性。综上表明,青稞富含总酚成分,是一种潜在的天然抗氧化剂资源。 相似文献
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Phenolic compounds are one of the most important quality parameters of wines, since they contribute to wine organoleptic characteristics such as colour, astringency, and bitterness. Furthermore, several studies have pointed out that many show biological properties of interest, related to their antioxidant capacity. This antioxidant activity has been thoroughly studied and a wide variety of methods have been developed to evaluate it. 相似文献
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Antonio Vega-Gálvez Kong Ah-HenMarcelo Chacana Judith VergaraJavier Martínez-Monzó Purificación García-SegoviaRoberto Lemus-Mondaca Karina Di Scala 《Food chemistry》2012,132(1):51-59
The aim of this work was to study the effect of temperature and air velocity on the drying kinetics and quality attributes of apple (var. Granny Smith) slices during drying. Experiments were conducted at 40, 60 and 80 °C, as well as at air velocities of 0.5, 1.0 and 1.5 m s−1. Effective moisture diffusivity increased with temperature and air velocity, reaching a value of 15.30 × 10−9 m2 s−1 at maximum temperature and air velocity under study. The rehydration ratio changed with varying both air velocity and temperature indicating tissue damage due to processing. The colour difference, ΔE, showed the best results at 80 °C. The DPPH-radical scavenging activity at 40 °C and 0.5 m s−1 showed the highest antioxidant activity, closest to that of the fresh sample. Although ΔE decreased with temperature, antioxidant activity barely varied and even increased at high air velocities, revealing an antioxidant capacity of the browning products. The total phenolics decreased with temperature, but at high air velocity retardation of thermal degradation was observed. Firmness was also determined and explained using glass transition concept and microstructure analysis. 相似文献
9.
Antonio Vega-Gálvez Karina Di Scala Katia Rodríguez Roberto Lemus-Mondaca Margarita Miranda Jessica López Mario Perez-Won 《Food chemistry》2009
Red pepper has been recognised as an excellent source of antioxidants, being rich in ascorbic acid and other phytochemicals. Drying conditions, particularly temperature, leads to pepper modifications that can cause quality degradation. In this work, the effects of process temperatures between 50 and 90 °C on physico-chemical properties, rehydration, colour, texture, vitamin C, antioxidant capacity and total phenolics during the drying of red pepper were studied. The rehydration ratio decreased with temperature and the maximum water holding capacity was achieved at 50 °C. Both vitamin C content and the total phenolic content decreased as air-drying temperature decreased. The radical scavenging activity showed higher antioxidant activity at high temperatures (i.e. 80 and 90 °C) rather than at low temperatures (i.e. 50, 60 and 70 °C). Chromatic parameters (L*, a*, b*, C* and H°), non-enzymatic browning compounds and extractable colour were affected by drying temperature, which contributed to the discolouring of pepper during this process. 相似文献
10.
Evaluation of the phenolic content,antioxidant activity and colour of Slovenian honey 总被引:1,自引:0,他引:1
Honey samples from the seven most common honey types in Slovenia were screened for total phenolic content by the modified Folin–Ciocalteu method, for potential antioxidant activity using the ferric reducing antioxidant power (FRAP) assay and by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method for antiradical activity. In addition the colour characteristics of honey samples were analysed. The results of the study showed that total phenolic content, antioxidant activity and colour parameters differ widely among different honey types. Phenolic content expressed as gallic acid equivalent ranged from 44.8 mg/kg in acacia honey to 241.4 mg/kg in fir honey. Antioxidant activity was the lowest in the brightest acacia and lime honeys and the highest in darker honeys, namely fir, spruce and forest. The colour of the Slovenian honeys, analysed in this study was very variable and ranged from pale yellow to dark brown. Correlations between the parameters analysed were found to be statistically significant (p < 0.05). 相似文献
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Geographical discrimination of honeys through antioxidant capacity,mineral content and colour
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Mariela Patrignani Cecilia Bernardelli Paula A. Conforti Néstor H. Malacalza Diego K. Yamul Edgardo Donati Cecilia E. Lupano 《International Journal of Food Science & Technology》2015,50(12):2598-2605
The assessment of geographical origin of honey is economically important for producers and consumers as every region may present particular quality characteristics. In this study, honeys from the seven different regions of Buenos Aires province (Argentina) were characterised by their antioxidant capacity (DPPH, FRAP), total phenolic content (TPC), mineral composition, colour and ash. Honeys showed significant differences among their antioxidant capacity (DPPH), ash, colour and mineral content (P ≤ 0.05). Besides, a good antioxidant activity and low amounts of Cu and Zn (<1.0–1.5 and 0.7–1.8 mg kg?1, respectively) were found in the samples. Significant Pearson's correlations (P ≤ 0.05) among the different parameters were found. Moreover, the linear discriminant analysis allowed the classification of honeys in their original groups with a prediction success of 98%. The present results suggest that honeys could be correctly classified by their geographical origin through their TPC, colour, ash and mineral concentrations. 相似文献
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Drying kinetics,physico‐chemical properties,antioxidant activity and phenolic composition of foam‐mat dried germinated rice bean (Vigna umbellata) hydrolysate
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Burachat Sritongtae Michael R. A. Morgan Kiattisak Duangmal 《International Journal of Food Science & Technology》2017,52(7):1710-1721
This research was aimed to study physico‐chemical properties and antioxidant activities of foam‐mat dried germinated rice bean (Vigna umbellata) hydrolysate. Germination led to an increase in released phenolic content and antioxidant activity (DPPH radical scavenging activity and FRAP) of rice bean hydrolysate. The hydrolysate obtained from germinated rice bean (GRB) and non‐germinated rice beans (NGRBs) was foam‐mat dried at 60 and 70 °C. Semi‐theoretical and empirical model could suitably describe the drying characteristic of foamed bean hydrolysate. Total phenolic content and antioxidant activities of foam‐mat dried samples decreased with increasing air‐drying temperature (P ≤ 0.05). Gallic acid, catechol and epicatechin were major phenolic compounds in foam‐mat dried samples prepared from both GRB and NGRB. The higher phenolic content and antioxidant activities were found in foam‐mat dried hydrolysate of GRB. Electron spin resonance spectrometry revealed that foam‐mat dried rice bean hydrolysate showed a strong ability to scavenge free radicals, especially carbon‐centred radicals. 相似文献
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B. N. Dar Savita Sharma Gulzar Ahmad Nayik 《Sensing and Instrumentation for Food Quality and Safety》2016,10(4):755-761
The objective of this investigation was to compare total phenolic content and antioxidant activities of various types of cereal brans enriched snack as affected by storage conditions. Extruded snacks were prepared by the addition of cereal brans (wheat, oat and rice) singly and in combination (w:r:o::2:1.5:1.5) to rice flour at 10, 20 and 30 % bran supplementation. The content of total phenolics in the extracts (conventional and microwave assisted extraction) was determined spectrometrically according to the Folin–Ciocalteu procedure and calculated as gallic acid equivalents. Radical scavenging capacity measured by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) methods was studied. The effect of the storage on antioxidant content and capacity showed that total phenolic content and antioxidant activities of bran enriched snacks decreased during storage at ambient temperature. However, a little increase in moisture content, water activity and free fatty acid was observed in six of month’s storage period. 相似文献
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《食品与发酵工业》2017,(1):73-79
采用超声波辅助,用不同极性的溶剂提取红果2号桑椹,测定并分析各提取浸膏的酚类含量,自由基清除能力、抗脂质过氧化能力、总还原力和DNA保护潜力。研究结果表明,乙醇提取物浸膏(absolute ethanol extracts of fruit,FAE)的酚类含量最高,为3.65 mg GAE/g dw,且总还原力和羟基自由基(·OH)清除力最强(P0.05);乙酸乙酯提取物浸膏(ethyl acetate extracts of fruit,FEE)的DPPH自由基(DPPH·)清除力(0.71mg/m L)和抗脂质过氧化能力最强;水提取物浸膏(water extracts of fruit,FWE)的ABTS自由基(ABTS+·)清除力最强(3.52 mg/m L),且能有效保护DNA不被损伤;石油醚提取物浸膏(petroleum ether extracts of fruit,FPE)酚类含量最低,且4种活性均最弱。基于实验结果,红果2号桑椹具有作为功能性保健品(天然抗氧化剂)的巨大潜力。 相似文献
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Kian Aun Chang Han Ni Kow Tzia-E Tan Kiat Liang Tan Lye Yee Chew Yun Ping Neo Vikineswary Sabaratnam 《International Journal of Food Science & Technology》2021,56(11):5639-5646
This study evaluated the effect of different cooking methods (microwaving, boiling, steaming and stir-frying) on the phenolic acids and antioxidant activity in Hericium erinaceus (HE). The total phenolic content (TPC) of HE decreased after cooking and was in the order of dried (control) > stir-fried > microwaved > steamed > boiled. An increase in antioxidant activity was found in all cooked HE, albeit statistically insignificant (P > 0.05). Gallic acid was reported to be the dominant phenolic acid found in HE extracts in the range of 3.03–49.41 μg g−1 dry weight. Low negative correlations were observed between 2,2-diphenyl-1-picrylhydrazyl (DPPH) and TPC as well as DPPH and gallic acid profile. Sensory data revealed that stir-fried HE received the most favourable response in colour, texture, aroma and flavour attributes. Overall, this study suggested that the method of stir-frying could be used to prepare HE for better retention of gallic acid and antioxidant activity with acceptable sensory characteristics. 相似文献
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The effect of temperature (20, 40, 60, 80 and 100 °C) on the rehydration kinetics and phytochemical constituents of dried edible Irish brown seaweed, Himanthalia elongata, were studied. The moisture content of fresh and dried seaweed was 4.07 and 0.07 g water/g dry basis, representing a 98.1% reduction in water content. All rehydration moisture curves had a clear exponential tendency, and it was observed that the rehydration time decreased when temperature was increased. Although restoration of the product to its original moisture content was achieved, rehydration resulted in losses in phytochemical content. Moisture equilibrium was achieved fastest at 100 °C (40 min) with losses of 83.2 and 93% in the total phenol and total flavonoid contents, respectively. The moisture content was fitted to empirical kinetic models; Weibull, Peleg’s, first-order and exponential association. Activation energies of 4.03, 4.28 and 3.90 kJ/mol were obtained for the parameters of Peleg’s, first-order and exponential models, respectively. 相似文献