不同成熟期灵武长枣酚类组分及抗氧化活性差异分析

对不同成熟期（白绿、微红、大半红、全红）灵武长枣酚类成分组成、含量及其活性的差异进行研究,以期发现不同成熟期灵武长枣抗氧化功能品质的变化规律。以宁夏不同成熟期的灵武长枣为研究材料,比较总酚、总黄酮及酚类物质的组成及抗氧化能力（DPPH自由基清除率、抗亚油酸过氧化能力和总还原力）的差异性。结果表明：1）4 个成熟期的灵武长枣总酚含量变化范围为2 996.60～5 801.84 μg/g（以没食子酸计）,总黄酮含量变化范围为33.12～122.12 μg/g（以芦丁计）,白绿期总酚和总黄酮含量最高,两者随着果实的成熟逐渐下降。2）灵武长枣中检出的酚类物质主要有根皮苷、阿魏酸、肉桂酸、柚皮素和根皮素,各含量均呈现先上升后下降趋势,微红期含量最高。3）灵武长枣抗氧化活性表现为白绿＞微红＞大半红＞全红。抗氧化能力与总黄酮、总酚含量呈显著相关性（P＜0.05）,与检测出的5 种酚类物质相关性较弱（P＞0.05）,决定其抗氧化能力的酚类物质仍有待进一步确定。白绿期灵武长枣的抗氧化活性均比其他成熟期高,因此从该时期获取天然抗氧化活性物质更为合适。     

低温低压静电场处理结合微孔PE膜包装对不同成熟度灵武长枣贮藏品质的影响

以不同成熟度(半红期、2/3红期和全红期)的灵武长枣为研究对象,采用低温低压静电场结合PE保鲜膜袋对其进行贮藏保鲜,分析不同成熟度的灵武长枣在贮藏期间抗坏血酸(VC)、总酸(TA)、可溶性固形物(TSS)、硬度和失重率等理化指标的变化,并进行感官评价。结果表明:全红期和半红期的灵武长枣保鲜期较短,软化、酒化速度快,营养成分损失快,而2/3红期的灵武长枣的保鲜效果最佳,果实水分损失最小;保持了较高的果实硬度和VC含量;减缓了可溶性固形物和可滴定酸的损耗,保持较好的口感。说明在(0.0±0.5)℃,200mV的低压静电场结合微孔PE保鲜膜袋的处理下,2/3红期的灵武长枣的在贮藏70d后,仍然保持了良好的食用品质。     

采收成熟度对‘京沧1号’枣贮藏品质及抗氧化活性的影响

为选择‘京沧1号’枣果实适宜长期贮藏的采收成熟度,以不同成熟度(初红、半红、全红)‘京沧1号’枣为试材,对比其果实品质特性,探究在(0±1)℃贮藏条件下果实品质的变化。结果表明,除可滴定酸外,不同采收成熟度‘京沧1号’枣各项品质指标存在显著性差异(P<0.05),随着贮藏时间的延长,其果实品质及抗氧化能力均不断下降。贮藏期末,果实硬度、抗坏血酸含量、总酚含量、可溶性蛋白含量、DPPH自由基和ABTS阳离子自由基清除率均表现为初红>半红>全红;失重率为初红>全红>半红;横纵径减失率、L^*值、固酸比为半红>全红>初红;a^*值、b^*值、可溶性固形物含量、可滴定酸含量、可溶性糖含量、类黄酮含量为全红>半红>初红。除此之外,全红果实在贮藏14 d后出现软化、酒化现象,商品性下降,而初红果实却能够保持良好贮藏性和商品性。综上所述,选择初红期成熟度的‘京沧1号’枣用于长期贮藏销售可以保持较好的外观和营养品质。     

基于介电特性的灵武长枣新鲜度预测

为了研究灵武长枣新鲜度与介电特性参数的关系,利用LCR测试仪在1.995kHz下测试长枣的介电特性参数,并对其介电特性参数和品质参数进行相关性分析。结果表明:长枣的介电损耗因子ε″与可溶性固形物含量、硬度、失重率、可滴定酸含量和丙二醛含量呈极显著相关(P0.01),相对相对介电常数ε′仅与呼吸强度显著相关(P0.01)。根据可溶性固形物含量、硬度和失重率的变化规律,将长枣分为3个新鲜度等级。以介电损耗因子ε″为BP神经网络的输入特征参数,利用BP神经网络结构建立长枣的新鲜度预测模型,新鲜度等级平均识别率达到81.67%,可用来预测灵武长枣的新鲜度。     

温度波动对灵武长枣贮藏品质的影响

为研究温度波动对灵武长枣采后贮藏品质的影响,将灵武长枣进行自发气调包装,然后在(0±0.1)、(0±0.5)、(0±1)℃下贮藏。通过测定灵武长枣贮藏期间感官品质、丙二醛、V_C、可滴定酸、可溶性固形物和电导率等来比较不同贮藏温度的保鲜效果。试验结果表明:(0±0.1)℃下贮藏的灵武长枣保鲜效果最好,有效维持灵武长枣的感官品质,减缓了V_C的降解,同时有效抑制可滴定酸和可溶性固形物含量的降低以及丙二醛的增长。     

采收成熟度对灵武长枣贮藏品质的影响

研究了灵武长枣三种采收成熟度的枣果经噻苯咪唑(TBZ)熏蒸,在20±0.5℃和-0.5±0.5℃温度下贮藏的呼吸强度、细胞膜透性和失重率的变化.结果表明,低成熟度耐贮藏,但品质较差;不同成熟度枣果经TBZ熏蒸后贮藏,贮期各项指标均相应得到提高;用适宜方法贮藏灵武长枣,综合考虑贮藏性和品质,可将中成熟度(即果面1/2～3/4红)作为最佳采收成熟度.     

川西藏区牦牛酸醡肉自然发酵过程中品质变化规律研究

为了探究不同生产季节川西藏区牦牛酸醡肉自然发酵过程中品质变化规律,研究了发酵温度(5、10、20、30、36℃)对发酵过程感官评价、菌落总数、理化特性、色泽特性和质构特性的影响。结果表明:(1)发酵期间产品感官评价先升后降,咀嚼性先降后升,伴随着菌落总数、总酸度、亚硝酸盐、挥发性硝基氮和硬度升高,pH、弹性和水分含量下降,期间色泽特性波动较大;(2)发酵温度越高,牦牛酸醡肉食用品质变化越大,发酵成熟时间越短,在5、10、20、30、36℃达到成熟时间分别为192、120、60、32、6 h;(3)不同温度条件下,发酵时间与产品弹性、a*呈极显著负相关(p0.01),与b*呈显著负相关(p0.05),与L*呈极显著负相关(p0.01);菌落总数与发酵时间、咀嚼性、a*、水分含量和亚硝酸盐均呈极显著正相关(p0.01),与硬度呈极显著负相关(p0.01)。     

灵武长枣贮藏过程中活性氧代谢和水分迁移与果实硬度的相关性

目的：研究鲜食灵武长枣在贮藏期间的活性氧代谢和水分迁移与果实硬度的相关性。方法：测定灵武长枣在常温（25?℃）和4?℃贮藏过程中相对电导率、丙二醛（malondialdehyde,MDA）含量、过氧化氢（H2O2）含量和硬度,同时结合低场核磁共振技术分析灵武长枣组织中水分迁移和含量的变化规律。结果：随着贮藏时间的延长,H2O2、MDA的含量和相对电导率均呈上升趋势,常温贮藏的鲜枣变化速率较4?℃变化更加显著（P＜0.05）;两种贮藏条件下鲜枣的相对电导率分别在第8天和第12天后迅速增加,此时鲜枣组织膜结构被破坏,H2O2和MDA大量积累;由水分迁移及不同水分的弛豫面积分析可知,随着贮藏期延长,贮藏过程中各个状态的水分子相互转化,两种贮藏条件下各阶段总弛豫面积A2和自由水弛豫面积A23变化趋势较一致,整体表现为显著下降趋势,不易流动水弛豫面积A22呈现先上升后下降趋势,常温和4?℃贮藏的鲜枣结合水弛豫面积A21分别呈下降和先升高后降低趋势。结论：4?℃贮藏的鲜枣水分流失较常温缓慢（P＜0.05）;硬度随贮藏期延长呈下降趋势,常温贮藏的鲜枣质构品质显著低于4?℃贮藏的鲜枣（P＜0.05）;相关性分析和通径分析结果表明,与A21、MDA含量、A23和相对电导率是影响鲜枣果实硬度的4 个主要指标,与硬度显著相关。该研究可为鲜食灵武长枣贮藏保鲜提供理论依据。     

采收期对阿克苏地区灰枣干制品品质的影响研究

以阿克苏地区灰枣果实为研究对象,研究采收期对其制干产品品质的影响。结果表明,随着采收的进行(9月20日~11月7日),灰枣干制品的总糖、还原糖和维生素C的含量均高于鲜枣;采收越晚,其制干产品总糖含量、总酸含量越高,且两指标与采收期相关性达到极显著(0.01)水平;制干产品的还原糖含量先上升,在10月3日~17日基本保持恒定,然后再升高,在10月24日有最大值(49.41%),然后逐渐下降;灰枣干制品维生素C含量先升高,至10月3日有最高值(370.28 mg/100 g FW),随后逐渐下降,10月3日后采收越晚其维生素C含量越低,且其与采收期呈显著负相关(达到0.05水平)。     

采收期对阿拉尔地区灰枣果实品质的影响研究

以阿拉尔地区灰枣果实为研究对象,研究灰枣在树上吊干过程中的生理生化变化规律及采收期对其品质的影响。结果表明:灰枣属呼吸跃变型果实,2014年9月26日左右阿拉尔地区灰枣有最大呼吸高峰,之后逐渐下降,果实逐渐走向成熟衰老;保持灰枣较高维生素C含量的采收期为9月20日—10月17日,9月26日—11月7日期间,采收期越晚,鲜枣总糖、还原糖含量越高,且其与采收期相关性达到0.01极显著水平;采收期越晚,鲜枣平均单果重、含水量越低,且其与采收期相关性也达到0.01极显著水平;总酸含量先上升后下降,在10月17日左右有最大值(0.485%FW)。     

金丝小枣在生长成熟过程中理化特性的变化规律

本文研究了6个不同生长成熟期(S1~S6)金丝小枣果实的色泽、叶绿素、可溶性糖及其代谢酶活性、有机酸及氨基酸的动态变化,以明确其代谢规律。研究结果表明:枣果生长成熟过程中,叶绿素含量降低,枣果由绿变红;葡萄糖、果糖均逐步积累,而山梨醇含量逐渐降低,蔗糖则在生长发育初期未被检出,其积累主要发生在枣果成熟后期,且其含量最高,金丝小枣为蔗糖积累型果实,蔗糖磷酸合成酶是蔗糖积累的关键酶;金丝小枣为苹果酸型果实,苹果酸随枣果的成熟而积累,而柠檬酸含量先上升后降低;Pro和Asp在枣果成熟过程中被大量合成,是成熟枣果中最主要的两种氨基酸。全红枣的可溶性总糖、糖酸比以及游离氨基酸总量最高,可作为金丝小枣鲜食的最佳采收时期。     

Ripening tomato fruit after chilling storage alters protein turnover

BACKGROUND: Tomato fruit is of prime importance owing to its qualities for human nutrition and its economic value. In order to extend its commercial life, it is harvested at mature but unripe stages and stored at low temperatures. The goal of this work was to study the influence of harvest and chilling storage of mature green tomato fruit (cv. Micro‐Tom) on the protein pattern, amino acid content and protease activity during fruit ripening. RESULTS: Fruits were sampled during ripening in three different conditions: 1, on the vine; 2, off the vine; 3, off the vine after 4 weeks at 4 °C. During all fruit ripening conditions, protein level decreased while amino acid content increased. Chilling storage of mature green fruit led to a reduction in protein content. Ripening off the vine (conditions 2 and 3) resulted in a threefold increase in red fruit amino acid levels when compared with red fruit on the vine. Protease activities (autoproteolytic, azocaseinolytic and gelatinolytic) were detected in all fruits evaluated and were differently affected by ripening stage, ripening conditions and the presence of specific inhibitors. CONCLUSION: Harvest and chilling storage increased endogenous substrate proteolysis, azocaseinolytic activity and free amino acid levels, which could be related to fruit quality. Copyright © 2011 Society of Chemical Industry     

草莓果实成熟过程中细胞壁组分变化的研究

目的研究草莓果实发育成熟过程中细胞壁成分的变化。方法以丰香和红丰草莓为试材，选择小而绿、大而绿、白熟、红熟、全熟5个时期采收，测定细胞组分含量。结果与结论随果实发育成熟，细胞壁中可溶性果胶和半纤维素增加，而离子结合果胶和共价结合果胶及纤维素减少，导致草莓果实成熟软化。     

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.     

Effect of sea water on biochemical properties of fruit of tomato (Lycopersicon esculentum Mill.) genotypes differing for ethylene production

BACKGROUND: Three near‐isogenic lines of cv. Gimar differing in ethylene production were used to evaluate the influence of salinity on fruit quality. Plants were grown in rockwool culture and were irrigated with nutrient solution with electrical conductivities (ECs) of 3 and 8 mS cm^?1, which corresponded to 0 and 10% of sea water. For fruits picked at ‘red‐turning’ and ‘red‐ripe’ stages physico‐chemical parameters, ethylene, ascorbate and organic acid content, and cell reductive power were analysed. RESULTS: The same response was observed in all genotypes: the higher salinity growth solution increased dry matter content, total soluble solids (TSS) and titratable acidity but reduced crop yield. Ascorbic acid and also organic acid contents showed a greater accumulation with ripening in the mutant genotypes: this might be due to a slowing of ripening. Our data confirm the lack of any relationship between the larger accumulation of TSS and ethylene production in the fruits of salt‐treated plants. CONCLUSION: These findings suggest that although salinity (10% sea water) reduces fruit yield, it does not have a negative effect on quality. So, it seems possible that controlled use of diluted sea water, combined with suitable tomato genotypes might represent a valid alternative to fresh irrigation water. Copyright © 2007 Society of Chemical Industry     

果色和成熟度对樱桃番茄（Solanum lycopersicum var. cerasiforme）果实挥发物分布的影响

为探究果色和成熟度对樱桃番茄果实挥发物的影响,用顶空固相微萃取-气相色谱-质谱联用法测定育种自交系材料金珠（橙）、黑樱桃1（紫）、1号（粉）、红珍珠（红）在绿熟期、转色期和红熟期的挥发物。分析发现,橙色番茄挥发物明显高于红色和粉色番茄。橙色番茄在绿熟期,紫色番茄在转色期和红熟期挥发物最高,而粉色番茄挥发物始终最低。气味强度由挥发物质量浓度和嗅觉阈值决定。3-甲基-丁醛、(E,E)-2,4-庚二烯醛、1-戊烯-3-酮、己醛、苯甲醛和(Z)-3-己烯-1-醇对番茄气味贡献较大。红色、橙色和紫色番茄分别在绿熟期、转色期和成熟期气味最浓。随着果实成熟,挥发物质量浓度持续增加,气味更加浓郁。果色和成熟度对挥发物有显著影响。     

真空冷冻干燥过程中鲜食枣营养品质的变化研究

本文研究了真空冷冻干燥过程中鲜食枣营养品质及抗氧化活性的变化规律,为实际生产加工产品选择合适的干燥时间提供理论依据。结果表明:冷冻干燥过程中,鲜食枣还原糖含量存在显著性差异,且干燥结束时显著升高(p0.05);冻干产品维生素C保留率高达99.58%;有机酸是产品中重要的风味营养物质,其中,草酸、柠檬酸含量在冻干过程中均存在显著性差异(p0.05),且在干燥结束时,草酸、酒石酸、柠檬酸含量分别是鲜样的1.64倍、1.32倍、3.83倍;冻干过程鲜食枣ABTS+·清除能力、抗氧化力均存在显著性差异(p0.05),且冻干后ABTS+·清除能力提高6.91%,抗氧化力保留率达92.01%。由此可见,冻干过程中冻干时间对营养物质含量及活性有重要影响。冻干6~9 h有利于保持贮藏的水分和较高的营养品质,同时有助于降低能耗,并保持其功能价值。     

Antioxidant Bioactive Compounds in Selected Industrial Processing and Fresh Consumption Tomato Cultivars

Four selected fresh consumption tomato varieties, harvested at different ripening stages (green, breaker, pink, red) and five industrial processing tomato varieties, harvested at red ripe stage, were analysed for lycopene and its isomers, β-carotene, total and individual phenolics, vitamin C and hydrophilic antioxidant activity. Tomato variety and ripening stage significantly affected carotenoids, total phenolic compounds and hydrophilic antioxidant activity when fresh consumption tomatoes were compared. The average of total lycopene content at the different ripening stages was 0.63, 12.20, 26.76 and 116.66 mg/kg of fresh weight (FW). Vitamin C ranged from 2.79 (breaker Cherry Pera) to 297.62 (red Cherry Pera) mg/kg FW. In green and breaker tomatoes, a positive correlation of hydrophilic antioxidant activity with vitamin C and chlorogenic acid was observed. However, in industrial tomato varieties (red ripe stage) and fresh consumption varieties harvested at pink and red stages, hydrophilic antioxidant activity was correlated with total phenolics and rutin. Tomato varieties for industrial processing did not show significant differences in total phenolic compounds and lycopene content. Lycopene ranged from 83.17 to 97.60 mg/kg FW, while total phenolic compounds varied between 257.91 and 284.13 mg/kg FW. Chlorogenic acid and rutin were the most abundant individual phenolics found in all the samples studied. Moreover, the content of total phenolics was always significantly correlated with the content of rutin. The amounts of all individual phenolics were affected by variety, with the exception of ferulic acid. Generally, these individual phenolics were more abundant in green and intermediate ripening stages, decreasing in full red tomatoes.     

Respiration rate,ethylene production and biochemical changes during fruit development and maturation of jujube (Ziziphus mauritiana Lamk)

Jujube fruits (Ziziphus mauritiana Lamk) of cv Zaytoni were harvested from fruit set until maturity to study some physiological and biochemical changes. Jujube fruit cv Zaytoni displayed a double‐sigmoid growth curve with a very short second stage (2 weeks). Changes in respiration rate and ethylene production during fruit development were typical of climacteric fruits, the peak of ethylene production coinciding with the climacteric rise in respiration. As for chemical constituents, reducing sugars were dominant and sucrose was absent in ripe fruit. Total soluble solid content was low during the early stages of growth, then increased to a peak in ripe fruit. Titratable acidity was low initially, but increased to a peak in physiologically mature fruit and declined rapidly in ripe fruit. The pattern of changes in protein content was typical of that characterising climacteric fruits. © 2002 Society of Chemical Industry     

Organic acids of various kinds of vegetables. IV. Changes in the acids and sugar in tomatoes, sweet peppers and cucumbers during development and ripening

Concentrations of organic acids and sugars in tomatoes and sweet peppers change notably during ripening. The concentration of malic acid decreases while that of citric acid increases considerably and in redripe fruits clearly exceeds the content of malic acid. Several maxima and minima in acid concentrations occur during development. Both species show constant proportions of citric and isocitric acid (200:1 and 30:1 respectively). In sweet pepper, quinic and ascorbic acid can be found in noticeably higher amounts than in tomatoes. Additionally, succinic acid was detected in tomatoes and fumaric and shikimic acid in sweet pepper. Glucose and fructose, in approximately equal amounts, are the main sugar components; their concentrations are increased during ripening, especially in sweet peppers. The leaves of tomatoes and sweet pepper contain more malic acid and less citric acid than redripe fruits, though here as well citric acid predominates. There is considerably less glucose and fructose present in the leaves of sweet pepper than in the fruits while sucrose is increased. Sucrose is the main sugar component in the leaves. Compared to tomatoes and sweet peppers, egg-plants contain more amounts. - Potatoes contain citric, malic, quinic, succinic, fumaric, and soluble oxalic acid (in order of decreasing amounts). - In cucumbers malic acid notably exceeds citric acid. Both acids hardly change in concentration during ripening. Sugar content decreases during ripening.