Antioxidant Activity of Different Extracts of Red Pitaya (Hylocereus polyrhizus) Seed

Antioxidant activity of three different extracts (ethanolic, chloroformic, and hexanic) of red flesh pitaya (Hylocereus polyrhizus) seed using free radical scavenging assay, linoleic acid model system, and ferric thiocyanate (FTC) method was determined. Ethanolic extract inhibit 74.76% of free radicals at 1000 μg/mL, while chloroformic extract gave the highest inhibition using linoleic acid model system (98.90% at 100 μg/mL) and FTC (96.34%) method. Total phenolic and ascorbic acid contents of the seed were 13.56 ± 2.04 and 0.36 ± 0.01 mg/g, respectively, while catechin was the major flavonoid detected. In conclusion, the study showed that both polar and non-polar compounds contribute to the antioxidative activity measured.     

不同pH值条件下火龙果色素的降解动力学

以火龙果色素提取液的吸光度变化为指标,研究其在pH2.0～9.0条件下的降解规律。结果表明：在室温(28℃)、pH2.0～9.0时,火龙果色素的最大吸收波长分别为532、534、536、534、535、536、538、543nm。火龙果色素在特定pH值条件下的降解符合一级反应规律。降解速率常数(k)与pH值呈抛物线关系。pH4.0～6.0范围内,k较小,色素稳定性较好。     

火龙果皮中膳食纤维含量及其物理化学特性

以火龙果果皮为原料,制备3种不同粒径的火龙果高膳食纤维果皮粉(DFRPP)：DFRPP80、DFRPP140和DFRPP250,测定其总膳食纤维、可溶性和不溶性膳食纤维含量,并对其持水性、持油性、溶胀性和对葡萄糖的透析阻滞能力进行研究。结果表明：粒径为58～104μm的DFRPP140中总膳食纤维和可溶性膳食纤维含量最高,分别为79.37%和33.07%,其可溶性膳食纤维与不溶性膳食纤维具有良好的比例模式,且其持水性、持油性和溶胀性最强,分别为54.20g/g、2.65g/g和50.63mL/g;其对葡萄糖的透析阻滞系数最好,在20、40、60min时分别是60.24%、59.24%和62.83%。DFRPP140可作为食品膳食纤维的优良来源。     

Nutraceutical potential and antioxidant benefits of red pitaya (Hylocereus polyrhizus) extracts

Polyphenols from flesh and peels of red pitaya (Hylocereus polyrhizus) fruit were quantified by employing an extract sub-fractionation procedure applied for the first time to this fruit. Higher polyphenolic contents than those from the literature were measured by using analogous spectroscopic techniques to those reported in previous works. Betacyanin fractions exhibited the highest reducing and radical-scavenging capacities among the extracts and fractions tested by FRAP and DPPH assays, respectively. Finally, polyphenolic fractions showed a broad antimicrobial spectrum by inhibiting the growth of all of food-borne pathogens tested, while the non-fractionated extracts revealed a very low or no activity. Results indicated flesh as a good source of antioxidants with healthy benefits for human diet and peels as a valuable manufacture by-product to be exploited for the formulation of nutraceuticals and food applications.     

Study on bioaccessibility of betacyanins from red dragon fruit (Hylocereus polyrhizus)

Food Science and Biotechnology - Betacyanins are bioactive dietary phytochemicals which can be found in red dragon fruit (RDF). Therefore, the bioaccessibility of betacyanins that present in...     

两种火龙果果皮红色素提取工艺优化及其抗氧化活性

以红肉红皮(RP)和白肉红皮(WP)火龙果果皮为原料,采用超声波辅助乙醇浸提法提取火龙果果皮红色素,并对其粗提物进行鉴定,通过单因素与正交试验优化提取工艺,同时测定两种果皮红色素提纯物质的总还原能力和自由基抗氧化活性。结果表明,经光谱法和HPLC-MS/MS联用法双重检测,火龙果果皮红色素为甜菜红素。WP中甜菜红素的最佳提取条件为:40%乙醇、料液比1:40 (g/mL)、超声时间25 min、超声温度40 ℃,色素最大得率为0.856%。RP中甜菜红素的最佳提取条件为:40%乙醇、料液比1:30 (g/mL)、超声时间15 min、超声温度30 ℃,色素最大得率为0.915%。RP以其纯化工艺流程获得的提纯物产量是WP的1.232倍。在一定浓度范围内,WP和RP火龙果果皮甜菜红素都有较强的总还原能力,但略低于V_C,清除DPPH·自由基、羟自由基(·OH)的IC₅₀分别为1.15和0.95 mg/mL、5.95和4.57 mg/mL,两者对亚硝酸根(NO₂^-)最大清除率分别为22.90%和25.10%,红肉火龙果果皮甜菜红素的综合抗氧化能力优于白肉红皮品种。     

Spray drying of red (Hylocereus polyrhizus) and white (Hylocereus undatus) dragon fruit juices: physicochemical and antioxidant properties of the powder

This study aims to investigate physical stability and antioxidant properties of spray‐dried red (Hylocereus polyrhizus) and white (Hylocereus undatus) dragon fruit powder upon storage at various relative humidity (RH). Inlet air temperatures of 120 °C (red dragon fruit) and 110 °C (white dragon fruit) as well as maltodextrin concentration of 30% (w/v) were selected as the spray drying conditions as powder was obtained at these minimum conditions. The powder was ranging from 3 to 7 μm in particle size with spherical morphology. The powder had lower antioxidant content and antioxidant activities compared with the control before spray drying. Storage of powder at 43%, 54% or 75% RH at 25 °C for 25 days resulted in structural changes correlating to the depression of glass transition temperatures (T_g) to below storage temperature. At 33% RH, no visible structural changes were observed. Antioxidant properties of the powder remained unchanged after 25 days' storage at the studied RHs.     

Physico-chemical and structural changes of red-fleshed dragon fruit (Hylocereus polyrhizus) during fruit development

BACKGROUND: Determination of physico‐chemical (weight, length, diameter, stomatal density, respiration rate, colour, soluble solids concentration, titratable acidity, chlorophyll and betacyanin content) and structural changes of red‐fleshed dragon fruit (Hylocereus polyrhizus (Weber) Britton & Rose) was carried out from 5 to 35 days after pollination (DAP) in order to explain their growth, development, maturations and ripening stages. RESULTS: Fruit growth of red‐fleshed dragon fruit followed a sigmoid growth pattern. Significant changes in colour were obtained in both peel and pulp as DAP progressed, which were indicated by reductions of L*, C* and h° values as both changed from green to red–violet colour at ripening. Red–violet betacyanin was manifested earlier in pulp at 25 DAP, followed by peel 4–5 days later, and finally both peel and pulp turned full red–violet by 30 DAP. There was a significant increase in soluble solids concentration and titratable acidity with the continuous increase in betacyanin content as DAP progressed. CONCLUSION: The physico‐chemical and betacyanin accumulation of red‐fleshed dragon fruit changed as it developed, matured and ripened which coincided with structural changes. Copyright © 2010 Society of Chemical Industry     

火龙果色素的基本性质及结构鉴定

采用液质联用(HPLC/MS)的方法,将色素的不同组分分离,并对分离组分进行结构鉴定.结果表明:火龙果果肉、果皮色素同为甜菜苷类色素,从果肉中分离出4种甜菜苷色素为betanin,2 descarboxy betanin,phyllocactin,2 descarboxy phyllocactin;果皮中分离出2种甜菜苷色素为be tanin,phyllocactin.火龙果中甜菜苷红色素的质量分数分别为676.9mg/kg(以鲜果肉计),97.7mg/kg(以鲜果皮计).     

超声波-酶解辅助提取火龙果皮色素的工艺优化

以火龙果皮干粉为原料,采用超声波-纤维素酶法辅助乙醇提取火龙果色素,通过单因素试验和正交试验考察纤维酶添加量、乙醇浓度、超声功率和提取时间对红龙果皮中的色素甜菜红素提取率的影响。结果表明最佳提取工艺条件为:纤维酶添加量为1 %、乙醇浓度为30 %、超声功率50 W和提取时间20 min,在此条件下火龙果皮中的甜菜红素提取率达70.06 %,制备的火龙果皮色素粉末的色价为2.071。     

Protein from Hylocereus polyrhizus protects MRC-5 cells against hydrogen peroxide (H2O2)-induced damage

Food Science and Biotechnology - The cytoprotective and potential molecular mechanisms of Hylocereus polyrhizus protein (RFPP) were investigated on the hydrogen peroxide (H2O2)-triggered damage in...     

Stability of betacyanin from red pitahaya (Hylocereus polyrhizus) and its potential application as a natural colourant in milk

The effects of temperature (30, 50, 85 and 100 °C) treatment and 10 weeks of refrigerated storage (4 °C) on the betacyanin content and colour stability of betacyanins from red pitahaya (Hylocereus polyrhizus) were investigated and compared to red beet (Beta vulgaris; E‐162) which was used as a control. Temperature treatment at 50 and 85 °C caused a greater reduction in betacyanin content (BC) in E‐162 compared to red pitahaya by inducing changes in betacyanin profile. The 10 weeks of refrigerated storage at 4 °C induced colour changes in betacyanins from red pitahaya and E‐162. In milk, betacyanins from red pitahaya presented a lower loss of BC and total colour changes (ΔE*) compared to E‐162. The microbial onset in milk containing betacyanins from red pitahaya and E‐162 was delayed up to day 5 of refrigerated storage at 4 °C compared to day 3 in plain milk. Milk containing betacyanins from red pitahaya showed better colour acceptability (3.89 ± 1.89) compared to E‐162 (6.10 ± 1.71). Hence, betacyanins from red pitahaya may be a potential natural functional colourant to simulate strawberry colour in milk.     

Influence of drying conditions on colour,betacyanin content and antioxidant capacities in dried red-fleshed dragon fruit (Hylocereus polyrhizus)

In this study, drying of red-fleshed dragon fruit at different temperatures (40, 50, 60, 70 and 80 °C) and air velocities (1.0 and 1.5 m s⁻¹) was conducted under the specific humidity of 25 g H₂O kg⁻¹ dry air. The results showed that drying at higher temperatures resulted in shorter drying times. However, temperature and air velocity did not significantly affect the total betacyanin contents and antioxidant capacities in dried products. Seven betacyanins identified by LC-MS were betanin, isobetanin, phyllocactin, isophyllocactin, betanidin 5 –O-(6′O-3-hydroxybutyryl)-β-glucoside, isobetanidin 5 –O-(6′O-3-hydroxybutyryl)-β-glucoside and decarboxylated phyllocactin. In addition, the temperature increased the isomerisation of betacyanins. The most preferable condition for preserving the colour and betacyanin contents of red-fleshed dragon fruit was the drying at a temperature of 80 °C and air velocity of 1.5 m s⁻¹ since it could shorten the drying time and give a bright red colour to the dried product as well as it had no significant impact on the betacyanins.     

南果梨红果皮中花青素提取工艺研究

本实验研究了南果梨红果皮中花青素提取条件对其提取量的影响。以南果梨红果皮中花青素提取量为技术指标,采用正交试验法,考察各工艺条件对提取效果的影响,确定了南果梨红果皮中花青素提取的优选条件。结论表明,0.1% HCl-甲醇溶液(pH4.0)以1:4的料液比混合后,在50℃下浸提两次,共计240min,提取量可达40mg/g,其检测数据可靠,提取方法简单合理。     

Effect of juice concentration on storage stability,betacyanin degradation kinetics,and sensory acceptance of red-fleshed dragon fruit (Hylocereus polyrhizus) juice

The aim of this study was to evaluate the effect of red-fleshed dragon fruit (Hylocereus polyrhizus) juice concentration on betacyanin degradation kinetics and sensory acceptance. The samples stored at 4°C were comparatively stable compared to 25°C in terms of betacyanin retention, and yeast and mold growth. The loss of betacyanin in red-fleshed dragon fruit juice and concentrate at 25, 37, and 45°C were of first-order reaction. The drink reconstituted from red-fleshed dragon fruit concentrate showed better acceptability in terms of sweetness, flavor, and overall acceptability. The current study demonstrated improved betacyanin retention and sensory acceptance of red-fleshed dragon fruit juice via juice concentration.     

减压法提取长枣枣皮中的天然色素

对减压法提取陕西长枣枣皮红色素进行了研究,通过单因素实验考察了碱液浓度、液料比、真空度、提取温度和提取时间对提取得率的影响,结合正交实验结果得出:在碱液质量分数1.6%,液料比40 mL∶1g,90℃下,真空度0.05 MPa,提取时间50 min时,色素提取得率最大,可达8.226 mg/g。减压提取、常压提取和超声提取三种工艺的对比结果表明减压提取所得红枣色素的色价最高,可达21.70,是常压提取的2.78倍(21.27/7.657),超声的1.84倍(21.27/11.524)。     

杨梅干红酒的酒质优化

以离子色谱、紫外可见分光光度法和气质联用等技术对乌酥梅和荸荠品种杨梅原汁的基本成分 ,以及杨梅干红优化实验样品的Aλmax值和主要芳香成分的相对含量进行了分析和研究。结果表明 ,荸荠品种杨梅原汁的酸度和色泽特性较适合杨梅干红的酿造 ,LAVIND4 7活性酿酒干酵母是优良的主酵菌种 ,采用 3%浓度的铝离子海藻酸固定化细胞 ,于 30℃发酵可获得较好的酒色和风味。