Extraction optimisation,antioxidant activity and inhibition on α-amylase and pancreatic lipase of polyphenols from the seeds of Syzygium cumini

The objectives of this study were to determine the optimal extraction conditions of polyphenols from Syzygium cumini seeds by response surface methodology and investigate their antioxidant activity and inhibition on α-amylase and pancreatic lipase. As results, the optimal extraction conditions in the ultrasonic extraction process which maximised total polyphenols content, minimised the IC₅₀ values of α-amylase and pancreatic lipase were determined as follows: extraction time 60 min, ethanol concentration 63% and solvent/solid ratio 44 mL g⁻¹. The main phenolic compounds in partially purified fraction of Syzygium cumini seeds were catechin, epicatechin, kaempferol, gallic, 5-caffeoylquinic, caffeic and ferulic acids. In addition, the partially purified fraction inhibited 87.66 ± 5.55 and 86.61 ± 3.15% of α-amylase and pancreatic lipase, respectively. The results suggested that Syzygium cumini seeds could be explored as a natural antioxidant and could be used as a source of highly antidiabetic and anti-obesity bioactive compounds.     

Composition of clove (Syzygium aromaticum) bud oil extracted using carbon dioxide

Analysis of clove (Syzygium aromaticum L) bud oil extracted with liquid and supercritical carbon dioxide shows significant qualitative and quantitative compositional differences compared with oil obtained by the conventional hydrodistillation process. The parameters of pressure, temperature, contact time etc, and also the clove oil components, affect the extraction of the bud flavour from the spice.     

Antioxidant capacity and hydrophilic phytochemicals in commercially grown native Australian fruits

Hydrophilic phytochemicals and antioxidant capacities of eight commercially grown native Australian fruits were determined. Kakadu plum (Terminalia ferdinandiana) contained a 6-fold higher level of total phenolic compounds and quandong (Santalum acuminatum) a 1.9-fold higher level of total phenolic compounds (TP, Folin–Ciocalteu assay) than blueberry (Vaccinum sp., cv. Biloxi). Both fruits displayed superior oxygen radical-scavenging capacity (ORAC-H assay) that was, respectively 4.1-fold and 6.5-fold of that of blueberry. The total reducing capacity (TRC; ferric reducing antioxidant power (FRAP) assay) of Kakadu plum and quandong exceeded the TRC of blueberry, respectively, 13.1- and 2.3-times. The primary sources of antioxidant capacities in the evaluated fruits were phenolic acids (benzoic and cinnamic) and flavonoids (flavonols, flavanones and anthocyanins) tentatively detected by liquid chromatography–mass spectrometry (LC–PDA–MS/MS). A high level of vitamin C was recorded for Kakadu plum and Australian citrus fruits. The major organic acids detected were citric and malic acid.     

Antioxidant capacity and phenolic compounds in commercially grown native Australian herbs and spices

The antioxidant capacities and phenolic composition in six native, commercially grown, Australian herbs and spices were investigated. Tasmannia pepper leaf, followed by anise myrtle and lemon myrtle contained the highest levels of total phenolics (TP; 102.1; 55.9 and 31.4 mg gallic acid equivalents (GAE)/g dry weight (DW), respectively). Tasmannia pepper leaf exhibited the highest oxygen radical absorbance capacity (ORAC assay) followed by lemon myrtle and anise myrtle. Anise myrtle exhibited the highest total reducing capacity [TRC; Ferric Reducing Antioxidant Power (FRAP) assay], followed by Tasmannia pepper leaf and lemon myrtle. Australian bush tomato, with TP content of 12.4 ± 0.9 mg GAE/gDW and TRC of 206.2 μMol Fe⁺²/gDW, resembled the Chinese Barbary Wolfberry fruit. The TP content of Tasmannia pepper berry (16.86 mg GAE/gDW) was similar to that of black pepper, but it’s TRC was 25% lower. Cinnamic acids and flavonoids, tentatively identified by mass spectrometry, were identified as the main sources of antioxidant activities.     

响应面法优化蒲桃叶总黄酮的提取工艺及其抗氧化活性

为研究蒲桃叶总黄酮的提取工艺及其抗氧化活性,以蒲桃叶为原料,采用微波辅助法提取其总黄酮.以单因素试验为基础,选择乙醇体积分数、液料比、微波功率、微波时间为自变量,总黄酮提取率为因变量,对蒲桃叶中总黄酮的提取工艺进行响应面优化.结果表明蒲桃叶总黄酮最优提取工艺为乙醇体积分数59％、液料比53:1(mL/g)、微波功率40...     

Aqueous extraction kinetics of phenolic compounds from jamun (Syzygium cumini L.) seeds

In this study, aqueous extraction of phenolic compounds from jamun (Syzygium cumini L.) seed was undertaken. The effects of various parameters such as extraction temperature (34.8–85.2°C), extraction time (49.8–100.2 min), and liquid-to-solid ratio (9.8–60.2 mL/g) on the extraction yield, extract purity (i.e., total polyphenol content), and its antioxidant activities (1,1-diphenyl-2-picrlthydrazyl free radical scavenging assay and ferric reducing antioxidant power) were investigated. Response surface methodology was used to optimize the extraction conditions. The optimum extraction conditions (49.2°C, 89.4 min, and 51.6:1 mL/g) produced an extract with 17.3% extraction yield, high total polyphenol content (415 mg gallic acid equivalent/g dried extract) and significant antioxidant activity (IC₅₀: 35.4 ± 0.7 µg/mL). The high-performance liquid chromatography analysis of seed extract revealed the presence of gallic acid (90.8 mg/g dried extract), ellagic acid (36 mg/g dried extract), caffeic acid (26.07 mg/g dried extract), p-coumaric acid (0.26 mg/g dried extract), catechin (9.05 mg/g dried extract), epicatechin (0.42 mg/g dried extract), and quercetin (1.54 mg/g dried extract). Tannic acid (188.5 mg/g dried extract) was also identified as a major phenolic compound. The extraction kinetics was also studied and experimental data were fitted to four kinetic models such as first-order model, second-order model, Peleg’s model, and Minchev and Minkov model, to evaluate their applicability.     

丁香、甘草与迷迭香的抑菌作用及其在酱油中的应用研究

该文研究了从丁香、甘草及迷迭香中提取抑菌防腐物质的方法及其抑菌效力、最低抑菌浓度(MIC)、活性pH范围及热稳定性等性能。经组合后取代苯甲酸应用于酱油防腐，存放2个月后检测卫生指标，全部合格。     

海南蒲桃果实原花青素的提取

以八成熟的海南蒲桃果实粉末为试材,采用正丁醇-盐酸法显色、测定提取液的吸光度,研究了八成熟海南蒲桃果实原花青素的提取工艺。经单因子实验及正交实验结果表明,以体积分数60%丙酮溶液(pH=3)为浸提液、料液比1∶9(g:mL)、温度60℃及时间2 h为最适工艺参数,经2次浸提原花青素的提取率为91.52%。八成熟的海南蒲桃果实原花青素含量5.70%,为充分成熟果实的127.23%。