Free and Bound Volatile Chemicals in Mulberry (Morus atropurpurea Roxb.)

Mulberry (Morus atropurpurea Roxb.) is a popular and desirable fruit that is widely cultivated in China. Despite its popularity, the free volatile chemicals and glycosidically bound volatiles (GBVs) of mulberry have been minimally studied. To this end, we have investigated these compounds in 4 mulberry cultivars via solid phase extraction (SPE) and headspace solid phase microextraction with gas chromatography–mass spectrometry (HS‐SPME‐GC‐MS). A total of 55 free volatile chemicals and 57 GBVs were identified and quantified. In 3 of the cultivars (“YFS,” “T10,” and “D10”), the GBVs were found in higher amounts than their free counterparts, corresponding to a ratio of 1.2 to 1.8. The characteristic aromas were determined by their odor activity values (OAVs) and by generating an aroma series (AS). A total of 20 volatile compounds had OAVs ≥ 1.0. In particular, ethyl butanoate, hexanal, (Z)‐3‐hexenal (E)‐2‐hexenal, (E)‐2‐nonenal, and eugenol had relatively high OAVs and were considered to be the key aromas contributing to the mulberry flavor. Consequently, mulberry was characterized by a variety of herbaceous scents having a background of sweet, spicy, fruity, and floral notes. The free volatiles exhibited strong herbaceous notes, whereas the GBVs were responsible for the sweet and spicy qualities of the fruit. Based on our results, 2 cultivars (“YFS” and “D10”) are proposed to be good candidates suitable for the further development of mulberry‐based food products due to their complex and desirable aromas.     

桑叶蛋白抗氧化肽的酶法制备

为了提高桑叶蛋白MLP的抗氧化活性,用碱性蛋白酶Alcalase、复合蛋白酶Protamex、木瓜蛋白酶Papain、风味蛋白酶Flavourzyme、中性蛋白酶Neutrase及胰蛋白酶Trypsin等6种蛋白酶对MLP进行单酶酶解及双酶、三酶复合酶解,并对酶解前后的化学组成、分子量分布、多肽得率、氨基酸组成、自由基清除能力、还原能力等进行对比分析。结果表明,MLP主要由分子量大于6.5 ku的大分子肽及蛋白质组成,酶解物则主要由分子量为0.3~0.6 ku的小肽及0.6~6.5 ku的多肽组成;相较于过度酶解,适度酶解能更好的改善MLP的抗氧化活性;多肽得率与自由基清除能力显著正相关(r=0.916~0.985);6种蛋白酶中,碱性蛋白酶、中性蛋白酶及复合蛋白酶的酶解物抗氧化活性显著优于MLP及其他三种蛋白酶解物;中性蛋白酶单独酶解物的抗氧化活性显著优于双酶、三酶复合酶解物。对中性蛋白酶的单酶酶解条件进行优化,结果表明底物浓度为20 mg/mL,E/S为1%(W/W),用中性蛋白酶酶解2 h所得的酶解物(NH)的抗氧化活性最高,后期研究中可选用中性蛋白酶制备桑叶蛋白抗氧化肽。NH或许可以作为食品中较有潜力的抗氧化剂。     

HPLC-DAD-ESI-MS/MS Analysis and Antioxidant Activities of Nonanthocyanin Phenolics in Mulberry (Morus alba L.)

ABSTRACT:  Qualitative analysis of the nonanthocyanin phenolics from 2 mulberry cultivars, da-10 and hongguo, was performed by the HPLC-DAD-ESI-MS/MS method. Six nonanthocyanin phenolics compounds were identified (procatechuic acid, chlorogenic acid, 4-caffeolyquinic acid, taxifolin, rutin, quercetin) and 3 others (3,5-diCQA, taxifolin-hexoside, kamepferol-hexoside) were tentatively identified. Quantification of nonanthocyanin phenolic was performed by HPLC-DAD, which revealed that rutin (111.38 and 90.79 μg/g FW) was the major nonanthocyanin phenolics in the 2 mulberry cultivars. Phenolic acids in cultivar da-10 (54.68 μg/g FW) were far more than in cultivar hongguo (14.93 μg/g FW). CQA and its isomers (40.02 μg/g FW) were the major phenolic acid in cultivar da-10. The nonanthocyanin phenolics in the 2 cultivars of mulberry had higher antiradical activities in superoxide anion and DPPH radical and antioxidant activity in β-CLAMS assay than the Trolox. These results were relevant to not only the control of color stability and organoleptic characteristics of mulberry juice and wine but also the exploitation of the functional foods made from mulberry.     

不同制备方法桑叶蛋白功能性质的比较

以广东桑大10为原料,采用水提法制备叶蛋白浓缩液,用加热法、酸沉法、酸热法、盐析法沉淀叶蛋白,分别得到蛋白样品RC、SC、SR、LC。对所得样品进行功能性质测定,与大豆分离蛋白对比,得出不同样品的功能特点。结果表明,异亮氨酸、赖氨酸分别为桑叶粉的第一、第二限制性氨基酸。不同沉淀方法对叶蛋白的功能性质有显著影响:LC的溶解性、起泡性、乳化性、吸油性最好,均优于SC、SR及RC;SR的持水性优于SC及RC,但乳化性、起泡性较差;RC、LC的胶凝性最好。与SPI相比,4个样品的吸油性均优于SPI,持水性、胶凝性则显著低于SPI(p0.05);LC的乳化稳定性(68.57%)及SC的起泡性(40%)最好,显著优于SPI(54.86%、37.67%),RC与SPI相当,SR最差,显著低于SPI(p0.05)。LC电镜扫描结果显示其具有典型的蜂巢结构。     

Phenolic Profiles,Antioxidant Activities,and Neuroprotective Properties of Mulberry (Morus atropurpurea Roxb.) Fruit Extracts from Different Ripening Stages

The present work investigated the phenolic profiles (including nonanthocyanin and anthocyanin phenolics), antioxidant activities, and neuroprotective potential of mulberry fruit (MF) (Morus atropurpurea Roxb.) grown in China at different ripening stages. High‐performance liquid chromatography‐tandem mass spectrometry method (HPLC‐MS/MS) was used to identify and quantify the phenolic compounds. The antioxidant capacity, total phenolic content (TPC), total flavonoid content (TFC), and total monomeric anthocyanin content (TAC) were determined using spectrophotometric methods. The neuroprotective effects of MFs at different ripening stages were investigated using Aβ_25‐35‐treated PC12 cells as the cellular model of Alzheimer's disease. Of the 19 phenolic compounds characterized from the MF extracts, the contents of rutin and anthocyanins increased and that of chlorogenic acid decreased significantly with maturity. At the fully ripened stage, MF extracts showed the highest amounts of TPC (11.23 mg gallic acid equivalents/g fresh weight), TFC (15.1 mg rutin equivalents/g fresh weight), and TAC (1177 mg cyanidin 3‐O‐glucoside equivalents/100 g fresh weight). Meanwhile, antioxidant activity of MF extracts at this stage was highest according to ABTS (an IC50 value of 4.11 μg/mL) and DPPH (an IC50 value of 10.08 μg/mL) assays. Cellular assays revealed increased cell viability in cells treated with the ripe MF extracts; compared with the control groups, the ripening fruits also increased the antioxidant enzyme levels in PC12 cells. Together, these results suggest that the antioxidant activities and neuroprotective properties of ripening MFs are related to the contents and types of phenolic compounds that are present in the fruits.     

烹饪方式对桑叶生物碱类和酚类物质的影响

研究微波、蒸、煮和油炸等烹饪方式对桑叶酚类物质组成变化和1-脱氧野尻霉素（1-deoxynojirimycin,DNJ）含量的影响。采用福林-酚比色法测定桑叶总酚含量,高效液相色谱-质谱法测定桑叶DNJ和酚类单体含量。结果表明：除了蒸3 min的桑叶总酚含量增加,所有烹饪处理后的桑叶DNJ和总酚含量均显著降低。蒸制处理后桑叶的总酚和DNJ含量最高,油炸处理DNJ含量最低,而微波（70 W）5 min桑叶酚类物质含量最低。不同烹饪方式对酚类组成影响显著,蒸3 min和微波（700 W）3 min的桑叶异槲皮素和紫云英苷含量增加,油炸的桑叶增加了山柰酚-乙酰基-葡萄糖苷、槲皮素和山柰酚等成分。综上,蒸制处理能保留桑叶中较多的活性成分,是适宜桑叶的烹饪方式。     

Comparison of Polyphenol Profile and Inhibitory Activities Against Oxidation and α‐Glucosidase in Mulberry (Genus Morus) Cultivars from China

Mulberry (genus Morus) is a significant source of polyphenols, which can promote positive effects on human health. China has various mulberry cultivars, however, many Chinese mulberry cultivars have been only minimally studied. To solve this lack of research, 8 mulberry cultivars (Da10, Tang10, Yueshen74, Yuefenshen, Longsang, Ningxia1hao, Taiwanguosang, and Baiyuwang) from 4 regions of China were assessed to determine their polyphenol profiles using HPLC‐MS/MS and then tested for their antioxidant and anti‐α‐glucosidase activities in vitro. A total of 18 nonanthocyanins and 4 anthocyanins were quantified in mulberry cultivars; among these polyphenols, chlorogenic acid, quercetin 3‐O‐rutinoside, and cyanidin 3‐O‐glucoside were confirmed as the major phenolic acid, flavonol derivative, and anthocyanin, respectively. Two types of stilbene compounds, piceid, and piceatannol, were detected for the 1st time in all mulberry cultivars. Moreover, the methanolic extracts of different mulberry cultivars showed disparate antioxidant and α‐glucosidase inhibitory activities, and this discrepancy was mainly attributed to varying the anthocyanin content. Based on our results, Taiwanguosang is proposed to be a good candidate suitable for further process due to its high level of anthocyanins.     

新疆药桑椹营养成分分析及其体外抗氧化作用

以新疆独特的药用果桑药桑椹为研究对象,分析药桑椹鲜果中总糖等基本营养成分及总黄酮等生物活性成分,并测定其体外抗氧化能力。药桑椹鲜果中总糖、粗纤维及粗蛋白含量分别为12.9、1.28、1.17 g/100 g,明显低于对照白桑椹。药桑椹中矿物质Ca、Fe含量为113 mg/100 g和11.9 mg/100 g,分别是白桑椹的1.6 倍及1.7 倍。药桑椹中VC与总酸含量高达48.4 mg/100 g与47.1 mg/g,分别是白桑椹的8.1 倍与8.4 倍。药桑椹中总多酚、总黄酮、多糖、花青素等生物活性物质含量均明显高于白桑椹,且其体外总抗氧化能力和清除DPPH自由基能力亦显著高于白桑椹。     

Phenolics,Aroma Profile,and In Vitro Antioxidant Activity of Italian Dessert Passito Wine from Saracena (Italy)

A traditional sweet dessert wine from Saracena (Italy), made with nonmacerated local white grapes (Guarnaccia, Malvasia and Moscato), was analyzed for phenolics and aroma profile and antioxidant activities. The most abundant classes of phenols identified by high‐performance liquid chromatography were hydroxybenzoic acids and flavan‐3‐ols, where gallic acid showed the highest content (376.5 mg/L). The analysis by solid phase microextraction‐gas chromatography‐mass spectrometry revealed the presence of superior alcohols (from iso‐butanol and iso‐amyl alcohol up to 2‐phenylethanol) and their ethyl esters, terpenes (such as linalool), furfuryl compounds, and free fatty acids (up to palmitic acid) as the key odorants of this wine. The antioxidant activity, evaluated by different in vitro assays 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH), 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid (ABTS), and β‐carotene bleaching test), showed that passito wine had a radical scavenging activity (IC₅₀ value of 0.03 v/v against DPPH·) and inhibited linoleic acid oxidation with an IC₅₀ value of 0.4 v/v after 30 min of incubation.     

桑叶粉添加量对生鲜面条品质及抗氧化活性的影响

为探究桑叶粉对生鲜面条品质及抗氧化活性的影响，扩大桑叶粉在面制品中的利用范围。该试验采用不同比例桑叶粉（0、2%、4%、6%、8%、10%）替代小麦粉制成混粉面团，进行温度扫描测定面团黏弹性。测定面条蒸煮特性、色差、质构、感官、抗氧化性等指标。结果表明，混合面团的黏弹性均在75~95 ℃左右显著增大。在一定范围内，随着桑叶粉比例增加，面筋网络结构致密均匀，内部结构显著改善，面条的硬度也显著增强，但是过量添加，导致淀粉颗粒之间缝隙较大，蛋白结构无序化，影响面筋网络结构稳定性。当桑叶粉添加量为4%时，生鲜面条断条率为0，蒸煮损失为5.07%，弹性、咀嚼性、感官评分皆达到最大值，分别为0.96 mm、7.70 mJ、90分。DPPH和ABTS+自由基清除率与对照组相比分别提高了2.69和1.27倍。在生鲜面条制作时加入一定量的桑叶粉制成的面团具有较好黏弹性，可以有效改善面条的蒸煮特性、质构特性、色泽以及感官评价，同时提高面条的抗氧化活性，为桑叶粉在面食及焙烤食品中的应用提供了参考依据。     

新疆药桑桑枝中桑色素的提取分离及鉴定

研究新疆药桑桑枝中桑色素的分离纯化工艺。采用乙醇浸提,有机溶剂萃取,聚酰胺树脂吸附色谱法对桑色素进行分离纯化;薄层层析色谱与高效液相色谱相结合的方式进行鉴定和检测。结果表明,经乙酸乙酯萃取,聚酰胺分离两次可纯化出桑色素;此外,在波长370nm 处桑色素具有良好的色谱吸收峰。聚酰胺能分离得到较高纯度的桑色素,是分离黄酮类化合物较好的材料。     

发酵和加工对桑椹抗氧化和降血糖作用的影响

目的：研究发酵和加工处理对桑椹抗氧化和降血糖作用的影响。方法：测定桑椹原粉（mulberry powder,MP）、桑椹发酵液（fermented mulberry,FM）、桑椹发酵液冻干粉（freeze-dried fermented mulberry,D（FM））、桑椹发酵液添加黄豆辅料后的冻干粉（freeze-dried fermented mulberry mixed with soybean,D（FM＋S））的单糖含量、菌落总数以及2,2’-联氨-双-3-乙基苯并噻唑啉-6-磺酸（2,2’-azinobis-(3-ethylbenzthiazoline-6-sulphonate),ABTS）阳离子自由基、1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基、羟自由基清除率和亚铁离子螯合能力、α-葡萄糖苷酶抑制率的变化。结果：桑椹经发酵、冷冻干燥处理后,基本检测不到果糖和葡萄糖;D（FM）中肠膜明串珠菌和酵母菌的存活率分别为54.77%、53.40%,而D（FM＋S）中两种菌的存活率都达到90%以上,说明添加黄豆辅料减少了冷冻干燥过程中益生菌的损失。ABTS阳离子自由基清除能力由强到弱依次为D（FM）＞D（FM＋S）＞MP＞FM;DPPH、羟自由基清除率以及亚铁离子螯合能力呈现出一致的趋势：D（FM）和D（FM＋S）清除能力最强,其次为MP,FM最弱。MP、FM、D（FM）、D（FM＋S）对α-葡萄糖苷酶的半抑制浓度分别为0.58、0.53、0.19、0.31 mg /mL,D（FM）和D（FM＋S）对α-葡萄糖苷酶的抑制效果优于MP和FM。结论：桑椹发酵和加工处理得到的冻干粉抗氧化能力和降血糖作用都比FM和未发酵的MP强。     

Antioxidant Activity of Pink-Flesh Guava (Psidium guajava L.): Effect of Extraction Techniques and Solvents

The effect of commonly used techniques and solvents in the antioxidant activities of pink-flesh guava fruit were studied. The extraction techniques compared were homogenization, shaking, sonication, magnetic stirring, and maceration for 1, 2, and 3 days. The solvent systems used were methanol, ethanol, and acetone at three different concentrations (50%, 70%, and 100%) and with 100% distilled water. The antioxidant activity of the fruit was evaluated using Folin–Ciocalteu index, ferric-reducing antioxidant power assay, and 1,1-diphenyl-2-picrylhydrazyl free radical-scavenging capacity. Ultrasonic and homogenization were the best techniques to extract the antioxidant from guava fruit. Homogenization technique was found to be the most convenient exhaustive and time-saving extraction technique. Results showed that the extracting solvent significantly (P < 0.05) altered the antioxidant property estimations of pink-flesh guava fruit. Pure solvents were inefficient extraction media for antioxidant. Enhanced extraction yields were obtained from solvent containing higher water concentrations and 50% acetone is a recommended solvent for extracting antioxidants compounds from pink-flesh guava fruit. High correlations between phenolic compositions and antioxidant activities of pink-flesh guava extracts were observed. High levels of antioxidant activities were detected in pink-flesh guava, indicating that the fruit may serve as an excellent dietary source of natural antioxidants.     

干燥方式对桑叶降糖活性成分含量的影响

本实验探讨了冷冻干燥、真空干燥、微波干燥和热风干燥4 种不同干燥方式对桑叶降糖活性成分的影响。采用高效液相色谱法测定桑叶1-脱氧野尻霉素（1-deoxynojirimycin,DNJ）含量、苯酚-硫酸法测桑叶多糖含量、亚硝酸钠法测定桑叶总黄酮含量。结果表明：冷冻干燥法制备的桑叶色泽最好,与新鲜桑叶最为接近,但DNJ和总黄酮的含量都较低;真空干燥法制备的桑叶DNJ和多糖含量最低,且桑叶的色泽也最差;微波干燥对桑叶的降糖成分和色泽影响较小,当功率为140 W处理10 min时,其DNJ和多糖的含量最高,分别为（297.15±6.35） mg/100 g和（11.71±0.01）%;热风干燥的时间较短,对桑叶的颜色影响也较小,当干燥温度为75 ℃,干燥时间为60 min,所得桑叶的DNJ、总黄酮、多糖的含量都较高,分别为（227.47±5.79）mg/100 g、（49.51±1.18）mg/g和（11.29±0.01）%。因此热风干燥更适合于工业化生产中大批量桑叶的干燥。同时测定对α-葡萄糖苷酶和α-淀粉酶的抑制作用可知干燥后桑叶降糖物质结构未发生改变,降糖效果依然存在。     

Antioxidant Activity,Total Phenolic Content and Selected Physicochemical Properties of White Mulberry (Morus Alba L.) Fruits

In this study, total phenolic content, antioxidant activity, mineral content and selected physicochemical properties of three white mulberry phenotypes (Morus alba L.) grown in Turkey were measured. Moisture, total soluble solids, total sugar, sucrose, reducing sugar, protein, ash, pH, titratable acidity, color (L, a, b), vitamin C, total phenolic, antioxidant activity of fruits were determined between 72.85–79.75 g/100 g fresh fruit, 21.25–28.50 g/100 g fresh fruit, 12.18–17.02 g/100 g fresh fruit, 1.57–4.36 g/100 g fresh fruit, 9.42–15.46 g/100 g fresh fruit, 0.82–0.89 g/100 g fresh fruit, 2.20–2.65 g/100 g fresh fruit, 5.70–5.86, 0.25–0.28 g/100 g fresh fruit, 31.24–68.69, ?2.46 to 15.68, 4.58–21.74, 10.15–21.50 mg/100 g fresh fruit, 18.16–19.24 μg gallic acid equivalent/mg of sample, and 33.96–38.96%, of sample respectively. Fruits were generally found high in P and low in Ca.     

Antioxidant Activity and Total Phenolics in Different Genotypes of Potato (Solanum tuberosum, L.)

Antioxidant activity of potato compared with that of broccoli, onion, carrot and bell peppers was higher than all except broccoli. Patatin appeared to be the major water-soluble compound that showed antioxidant activity. The activity varied among potato cultivars, but was not related to flesh color or total phenolics. Antioxidant activity was evenly distributed within tuber parts and/or sections, except for skin tissue which had the greatest antioxidant activity and total phenolic content. Total phenolics varied among cultivars, with some containing twofold higher concentrations than other cultivars. Phenolic content differences were genotype dependent and not related to flesh color.     

加速溶剂提取法快速分析乌龙茶内含呈香组分

加速溶剂提取法（Accelerated solvent extraction,ASE）是近年来最先进的样品前处理技术之一,具有快速高效等特点.本研究应用ASE技术对凤凰单枞乌龙茶（Camellia sinensis）的呈香组分进行富集,设置最优条件是使用40ml乙酸乙酯为提取溶剂,提取压力9MPa,提取温度120℃,可对10.00g乌龙茶样品的香气成分有效提取,提取时间仅为5min;结合气质联用仪分析鉴定.结果表明采用ASE富集凤凰单枞乌龙茶香气组分,从桂花香型凤凰单枞乌龙茶中检测出63种香气组分,其中较高的组分有芳樟醇、橙花叔醇、壬酸、癸酸、香叶醇、十六烷和3,7-二甲基-1,5,7-辛三烯-3-醇.ASE法可对乌龙茶内含香气组分进行无损富集和快速检测,避免茶叶内含不稳定的香气组分被破坏,减少茶叶香气组分检测的误差和不稳定性.     

响应曲面法优化新疆药桑桑皮总多酚提取工艺

采用响应曲面法对新疆药桑桑皮中多酚类化合物的提取工艺进行优化。在单因素试验的基础上,选择乙醇体积分数、提取温度、提取时间,进行三因素三水平的Box-Behnken 中心组合试验设计,采用响应曲面法(RSM)分析3 个因素对响应值的影响。结果表明：最佳提取工艺条件为溶剂中乙醇体积分数78%、提取温度70℃、提取时间240min、液料比30:1(mL/g),在此条件下,总多酚的得率达到0.793%。该工艺稳定可靠,可在生产中应用。     

Ultrasound-Assisted Extraction of Phenolics from Longan (Dimocarpus longan Lour.) Fruit Seed with Artificial Neural Network and Their Antioxidant Activity

Longan (Dimocarpus longan Lour.) is a non-climacteric subtropical fruit which is widely accepted by consumers all over the world for its pleasant flavor and health benefits. In the present work, the effects of ultrasonic power (120?C300?W), temperature (30?C70?°C) and ethanol concentration (40?C80%) on the yield of total phenolics and 1,1- diphenyl-2- picrylhydrazyl (DPPH) radical scavenging activity were investigated with artificial neural network, and they were proved to be interactional and significant on the dependent variables. The R ² and MSE values of the models suggested good fitness and generalization of the artificial neural network. The results indicated a positive linear relationship between antioxidant activity and total phenolic content. Compared with conventional extraction, ultrasound-assisted extraction showed a higher yield of total phenolics and required a shorter extraction time. A stronger antioxidant activity of the ultrasonic extract was also found compared with conventional extraction.