Influence of Harvest Periods on Cassava (Manihot esculenta Crantz) Agronomic Traits and Physiological Response to Post-Harvest Physiological Deterioration

Cassava (Manihot esculenta Crantz) is the third largest source of calories in tropical countries and the sixth most important food crop in the World. However, the short shelf life of its storage roots after harvest due to a rapid post-harvest physiological deterioration (PPD) makes the roots to be considered as a risky product to market. The objectives of this work were to investigate the influence of two harvest periods on cassava agronomic parameters and their physiological response to PPD. Three cassava cultivars 96/1414, I070593 and LMR were selected for the experiment and harvested at 10 and 12 months after planting (MAP). The response to PPD was assessed during storage at 0, 3, 8 and 15 days after harvest (DAH). Total proteins content, soluble sugars and starch, total polyphenols compounds, polyphenoloxidase and peroxidase activities were recorded during storage. Results showed large variation among the parameters at the two harvest periods across the cultivars. High number of tubers was recorded in all the cultivars at 12 MAP and a significant increase in storage roots length was observed in 96/1414 and LMR from 10 MAP to 12 MAP (25 ± 5.1 to 41.3 ± 5.9 and 22.6 ± 3.3 to 27.9 ± 4.8) respectively. A reduction of about 49% of tubers weight was observed in I070593 from 10 to 12 MAP while an increase of about 36% and 11% were recorded in LMR and 96/1414 respectively. Tubers from I070593 showed less susceptibility to PPD when harvested at 10 MAP compared to those from LMR and 96/1414 where less susceptibility to PPD were recorded at 12 MAP. An increase in soluble sugars content, total proteins content and peroxidase activity subsequently to a decrease in starch content were recorded during storage from 8 to 15 days after harvest especially at 10 MAP in I070593 and at 12 MAP in LMR and 96/1414. High content of total phenolic compounds and less activity of polyphenol oxidase were correlated to PPD susceptibility. This work opens a new insight issue of the consideration of the appropriate harvest time of the cultivars as a tool to better control the onset of postharvest physiological deterioration.

FAA Composition and Content Variation in Different Pyropia yezoensis Cultivar in Harvest Period

The contents of 16 kinds of free amino acids （FAAs） in 7 Pyropia yezoensis cultivars were determined by pre-column derivatization high performance liquid chromatographyin early, middle and late harvest period.The results showed that the total FAA content ranged from 48.71 to 62.05 mg/g among the 7 test ma- terials. Among the 16 kinds of FAAs, Ala, Arg, Glu and Asp, four kinds of flavor amino acids, showed the highest contents, and their total content ranged from 36.05 to 53.96 mg/g, accounting for 69.11%-86.47% of the total FAA content. The total contents of flavor amino acids and FAAs all reached the peaks in all the test ma- terials, except the control cultivar, at middle harvest period. The essential amino acid content was trended to be increased in all the test materials with the extended harvest period, and it reached the peak at the late harvest period. Sutong showed the highest flavor amino acid content and FAAs content, followed by Y-H002, Suyan and Sulian, while the control cultivar showed the lowest contents.

Study on chemical composition of Viscum coloratum and its HPLC fingerprint in different harvest periods

The purpose of this study was to evaluate the similarity of chemical profile of Viscum loloratum harvested in different months using high performance liquid chromatography(HPLC)fingerprint and multivariate statistical analysis,and to determine the optimal harvest time of Viscum coloratum.8 compounds were isolated from Viscum coloratum by a variety of isolation techniques,3 of which were isolated from the genus Viscum L.for the first time.The fingerprint of Viscum coloratum was established by HPLC,and 16 common peaks were obtained,4 of which were identified by comparison with the reference substances.Results showed that the Viscum coloratum harvested in 6 months could be roughly divided into three groups based on the chemical profiles,and the Viscum coloratum harvested in January had higher levels of the marked compounds.The HPLC fingerprint objectively reveals the characteristics of Viscum coloratum harvested in different months,which can be used to evaluate and control the quality of Viscum coloratum harvested in different months.

Effects of Different Harvest Periods on Seed Quality of Alpinia oxyphylla Miq.

[Objectives] To clarify the appropriate harvest period of Alpinia oxyphylla Miq. seed and improve the quality of seeds. [Methods] In this experiment,the basic parameters and germination characteristics of A. oxyphylla Miq. seeds during different harvest periods were analyzed and compared. [Results] The results showed that the A. oxyphylla Miq. fruit picking period was closely related to the seed quality,and the seed maturity was highest 100 d after the flowering of A. oxyphylla Miq.,that is,the A. oxyphylla Miq. fruit skin turned from green to yellow( yellow-green),the peel had a small number of brown spots,it was spicy enough,the fruit dry/fresh weight ratio was greater than0. 34,the seed thousand kernel weight reached 11 g or more,and the dried seed moisture content was 13. 01%. Using the TTC method,the seed viability index was determined to be 85%,and in this case,it was the best time of harvesting seed. The water permeability of A. oxyphylla Miq. seed was poor,and the seed imbibition and water absorption time was long,about 72 h. The maximum water absorption rate was about23. 71% at the imbibition and water absorption stage,and it was inferred that the A. oxyphylla Miq. seeds were hard seeds. The germination time of A. oxyphylla Miq. seeds was long,the mature A. oxyphylla Miq. seeds began to germinate on the 12 th d,and the germination rate reached 75. 56% on the 50 th d. [Conclusions] This study determined the optimum harvest period of A. oxyphylla Miq. seeds,clarified the biological characteristics of slow seed water absorption and long germination cycle,and concluded that the seed coat was the main factor leading to slow seed water absorption and long seed germination cycle.

Comprehensive evaluation of Korla fragrant pears and optimization of plucking time during the harvest period

To optimize the harvest of Korla fragrant pears and to provide a theoretical basis for post-harvest processing,a total of 26 basic indices of Korla fragrant pears,including their morphology,quality,and softening age,were investigated.The harvest period ranged from August 22nd to October 6th,samples were collected every 5 d(totally 10 plucking days,indicated as H1-H10).The results indicated that changes in pectin content were the main causes of softening in fragrant pears.The scavenging of free radicals mainly occurred because of the collaborative effects of superoxide dismutase(SOD)and catalase(CAT).In the harvest periods H1-H3,the hardness,titratable acid(TA),chlorophyll content,density,and diameter of the stone cells,as well as the cellulose and hemicellulose content of the Korla fragrant pears were at their highest.During the periods H7-H10,the single-fruit weight,fruit horizontal and vertical diameter,color coordinates L,a*,b*,soluble-solids content(SSC),SOD activity,CAT activity,and water-soluble pectin were higher than in the other plucking periods.The highest vitamin C(VC)content and moderate values for a variety of indicators were observed during H3-H7.Variations in the Korla fragrant pears during H1-H3 mainly manifested through changes in softening-related parameters.During H3-H10,changes in the softening-related,aging-related,color-related,and quality indices had a dominant role.On this basis,some suggestions for the post-harvest processing of fragrant pears have been proposed.Fruit,during H1-H3,are suitable for transportation and storage;during H7-H10 are suitable for fresh-eating and further processing;and during H3-H7,exhibited moderate values for a variety of indicators and had the highest commercial value.This research provides a systematic evaluation of the characteristics of mature Korla fragrant pears during the harvest period and can form the basis for fruit quality control and processing of Korla fragrant pears.

Existence of two periodic solutions of a ratio-dependent Holling-Taner model with infinite delay and prey harvest

This paper considers a class of ratio-dependent Holling-Taner model with infinite delay and prey harvest, which is of periodic coefficients. By means of the coincidence degree theory, a set of sufficient conditions for the existence of at least two positive periodic solutions of this model is established.

Modeling and analysis of piezoelectric beam with periodically variable cross-sections for vibration energy harvesting

A bimorph piezoelectric beam with periodically variable cross-sections is used for the vibration energy harvesting. The effects of two geometrical parameters on the first band gap of this periodic beam are investigated by the generalized differential quadrature rule （GDQR） method. The GDQR method is also used to calculate the forced vibration response of the beam and voltage of each piezoelectric layer when the beam is subject to a sinusoidal base excitation. Results obtained from the analytical method are compared with those obtained from the finite element simulation with ANSYS, and good agreement is found. The voltage output of this periodic beam over its first band gap is calculated and compared with the voltage output of the uniform piezoelectric beam. It is concluded that this periodic beam has three advantages over the uniform piezoelectric beam, i.e., generating more voltage outputs over a wide frequency range, absorbing vibration, and being less weight.

北五味子的采收加工与炮制研究进展

总结近年采收期对北五味子中木脂素、有机酸、多糖等多种成分的影响,考察晒干、阴干、烘干等产地初加工方法,以及醋制工艺、酒制工艺、盐制工艺等,炮制后北五味子中化学成分的变化,炮制后北五味子镇静催眠、降血糖、保肝和保肾等药理作用变化情况,指出北五味子具有多种药理活性,在多种常用复方中均有使用,应用前景广泛,但仍需要运用现代科学技术全面开展北五味子采收、加工、炮制等方面的研究,为北五味子的临床合理应用提供参考。

全株小麦青贮适宜收获期及青贮添加剂配比技术的研究

为了确定全株小麦作为青贮饲料的适宜收获期及最佳的青贮添加剂配比组合,首先分析了全株小麦开花期、乳熟期、蜡熟期的干物质产量及营养成分含量,综合各生育期全株小麦的各项饲用指标(可消化干物质产量、非结构性碳水化合物含量等),表明蜡熟期是最适宜作为青贮的时期。其次通过添加不同浓度的乳酸菌与糖蜜来研究添加剂配比组合对全株小麦青贮料发酵效果及养分损耗,结果表明同时添加两种添加剂的全株小麦青贮料的饲用品质和发酵品质显著优于只添加其中一种添加剂。两种添加剂配比中,添加乳酸菌浓度较低时(≤0.02‰),糖蜜添加浓度为2%较添加浓度为1%的全株小麦青贮料的饲用品质和发酵品质好;添加乳酸菌浓度较高时(≥0.04‰),糖蜜添加浓度的变化对全株小麦青贮料的饲用品质和发酵品质影响不显著。研究结果可为全株小麦青贮适宜收获期以及乳酸菌与糖蜜配比组合在青贮饲料中应用提供参考。

贯叶金丝桃(Hypericum perforatum)种子灌浆与发芽特性研究

贯叶金丝桃(Hypericum perforatum)是抗抑郁中药的基原植物,以有性繁殖为主,种子微小。为了揭示贯叶金丝桃种子发育规律,明确种子适宜采收期,以甘肃礼县栽培的2年生贯叶金丝桃为研究对象,于开花后第5天开始,每隔3 d测定种子粒重变化动态,并拟合Logistic曲线方程,最后测定各时期采收种子的发芽指标。结果表明:贯叶金丝桃种子灌浆持续期44 d,籽粒干质量变化符合Logistic生长曲线:开花后第5~11天为渐增期,第11~32天为快增期,第32~44天进入稳增期后略有下降。在灌浆过程中,种子鲜质量呈先升高后下降的动态变化趋势,在花后第32天达到最大值0.2697 g;灌浆速率和脱水速率呈波动趋势,种子干质量与平均灌浆速率、灌浆持续期呈极显著正相关,与含水量呈极显著负相关。种子发芽率和发芽指数在开花后44天达到最大,发芽势在开花后41天达到最大,发芽率、发芽势和发芽指数均与灌浆持续期呈极显著正相关,与含水量呈极显著负相关。以上说明甘肃礼县贯叶金丝桃繁种时以开花后44天左右(8月9日前后)为种子采收适宜期,过早采收和延迟采收均影响种子发芽质量。

不同采收期对轮台白杏果实品质及代谢物的影响

为探究不同采收期对轮台白杏果实品质和代谢物的影响,对轮台白杏不同采收期(S1~S6)果实的品质进行了测定,同时采用广泛靶向代谢组学技术对不同采收期果实中代谢物进行了研究。结果表明,随着果实的成熟,果实单果重、可溶性固形物、可溶性总糖、色泽指数、pH值不断上升,而果实硬度、可滴定总酸呈现出逐渐下降的变化趋势。维生素C含量呈现出先上升再下降的变化趋势,在S3时达到最大值。在6个不同采收期果实中鉴定出867种代谢物,包括黄酮类、脂质类、木脂素和香豆素类类、生物碱类、萜类、鞣质类、其他类(包含糖类、醇类及维生素)、酚酸类、氨基酸及其衍生物、有机酸、核苷酸及其衍生物、甾体等12大类,其中黄酮类物质数量最多,为191种,占总代谢物的22%。通过对差异较大代谢物进行分析,糖类物质、有机酸、黄酮类和氨基酸及其衍生物是造成不同采收期轮台白杏果实口感、风味差异的根本原因。研究结果表明,S3和S4时期为轮台白杏的最佳采收期。

Periodic Solution for Stochastic Predator-Prey Systems with Nonlinear Harvesting and Impulses

In this paper, astochastic predator-prey systems with nonlinear harvesting and impulsive effect are investigated. Firstly, we show the existence and uniqueness of the global positive solution of the system. Secondly, by constructing appropriate Lyapunov function and using comparison theorem with an impulsive differential equation, we study that a positive periodic solution exists. Thirdly, we prove that system is globally attractive. Finally, numerical simulations are presented to show the feasibility of the obtained results.

植物不同生长期成分含量变化研究

综述了植物不同生长期多酚、多糖、氨基酸和蛋白质、萜类和挥发性成分含量变化的研究现状,为药材质量评价、确定最佳采收期、合理施肥、果蔬质量控制、副产物的合理开发利用等提供理论依据。

不同产地沃柑品质差异分析

以4个产地(武鸣、全州、贵港、靖西)不同采收期的沃柑为研究对象,分析其色泽、理化特性及营养成分变化。结果表明:沃柑品质因产地和采收期不同而呈现出差异,随着采收期延长,4个产地的沃柑L*值、b*值、可滴定酸、总酚及柠檬苦素含量均呈降低趋势,a*值、可溶性固形物含量、固酸比、维生素C含量及类胡萝卜素含量不断升高,氨基酸含量呈现动态变化趋势。聚类分析显示武鸣、全州、贵港、靖西采收期Ⅰ的沃柑归为一类,全州、贵港采收期Ⅱ、Ⅲ和武鸣、靖西采收期Ⅱ的沃柑归为一类,武鸣、靖西采收期Ⅲ的沃柑归为一类。研究结果表明,采收期Ⅰ、Ⅱ的武鸣、全州、贵港、靖西沃柑品质无差异,采收期Ⅲ的武鸣、靖西沃柑品质优于全州、贵港沃柑,采收期Ⅲ的武鸣、靖西沃柑果实色泽诱人、酸甜可口无苦涩味、营养丰富,较适合鲜食和加工。

瓶尔小草总黄酮提取工艺优化及不同采收期含量变化规律研究

探究瓶尔小草的最佳采收时期,优化瓶尔小草总黄酮的提取工艺,并评价其体外抗氧化活性。以总黄酮含量为考察指标,对乙醇浓度、料液比、超声时间、提取温度进行单因素实验,并结合响应面法设计优选超声波辅助提取工艺。结果表明:瓶尔小草总黄酮的最优工艺条件为超声提取温度为40℃,乙醇浓度为65%,料液比为1∶30(g/mL),超声时间为35 min;一年中瓶尔小草的总黄酮含量变化存在两个富集期,最佳采收期为8月,其次4月份也较为适宜采收。以维生素C为对照,瓶尔小草黄酮提取物对DPPH自由基、ABTS^(+)自由基清除率分别可达94.76%和98.33%,瓶尔小草总黄酮的总还原能力测定IC_(50)为0.0157 mg/mL,说明瓶尔小草总黄酮具有良好的体外抗氧化活性。本研究为瓶尔小草的采收、开发利用提供了试验依据。

播种期及收获期对饲用小黑麦生产性能和营养品质的影响

为探明适宜宁夏半干旱区小黑麦(Triticosecale Wittmack)生产的播种期和刈割时期,以宁夏饲用小黑麦主推品种‘晋饲草1号’为研究材料,设置了3个小黑麦播种时期(S)和2个刈割时期(H),共6个处理,开展不同播种期和收获期对牧草生产性能和营养品质的影响研究,并应用主成分分析进行综合评价。结果表明,小黑麦的株高和叶面积随着播种期和收获期的延后显著增高(P<0.05);小黑麦干草产量和粗蛋白产量随着播种期的延后呈先增加后下降的趋势,小黑麦干草产量最大的处理为S2H2(9 665.74 kg·m^(-2)),粗蛋白产量最大的处理为S2H1,达881.15 kg·hm^(-2);不同播种期及收获期显著影响小黑麦营养品质(P<0.05),粗蛋白含量最高的为S2H2(10.18%),S1H2的相对饲喂价值最大。主成分分析综合排名第一的为S2H2(播种时间为9月20日,收获时间为灌浆期),是均衡饲用小黑麦产量和营养的理想组合,可作为宁夏雨养区饲用小黑麦播种和收获的参考依据。

不同采收阶段的坛紫菜营养成分分析及预测模型

为获取不同采收阶段坛紫菜的区分方法,以4个采收阶段坛紫菜为原料,测定其色泽、营养物质、氨基酸等营养成分指标。依据坛紫菜采收阶段与营养成分指标的相关性建立模型,预测坛紫菜适宜的采收阶段。结果表明,随着坛紫菜采收阶段的增加,L*和b*值显著上升(P<0.05),而a*值呈下降趋势;蛋白质、必需氨基酸、非必需氨基酸和总氨基酸含量先减小后增加,脂肪和粗纤维分别呈现下降和上升趋势,灰分含量先上升后下降。此外,三水坛紫菜中鲜味氨基酸的TAV值最高,四水坛紫菜中甜味氨基酸的TAV值最高,只在四水坛紫菜中检测到C16∶1和C18∶3,采收后期坛紫菜的矿物质元素含量高于采收前期。根据除蛋氨酸外的必需氨基酸含量拟合的回归曲线,可准确鉴定不同海域的头水坛紫菜。本研究建立了坛紫菜采收阶段与相关品质指标的关联模型,为不同采收阶段坛紫菜的鉴定筛选及高值利用提供了技术参考。

施肥和收获期对拉萨河谷地区白草产量和饲用品质的影响

为探究西藏地区白草(Pennisetum flaccidum)优质、高产的种植方式,本研究在拉萨河谷区设置N_(0)(0 kg·hm^(-2))、N_(300)(300 kg·hm^(-2))、N_(600)(600 kg·hm^(-2))和N_(900)(900 kg·hm^(-2))施肥处理,分别于抽穗期、乳熟期和成熟期采集试验样品,分析不同施肥梯度和收获期对白草产量、饲用品质和土壤养分的影响。结果表明:白草干草产量随施肥量增加呈上升趋势,在抽穗期和成熟期显著高于乳熟期(P<0.05)。白草粗蛋白含量随收获期推迟而逐渐降低,粗灰分含量随施肥量增加呈下降趋势,但施肥对不同收获期的白草酸性洗涤纤维、中性洗涤纤维、粗脂肪和酸性洗涤木质素含量均无显著影响(P>0.05)。白草土壤全氮含量在抽穗期随施肥量增加呈现先增后减趋势,全磷含量随施肥量增加以及收获期的推迟而趋于下降。在抽穗期收割N_(900)处理的白草生产性能最佳,其次是同期收割N_(600)处理的白草,但后者较前者拥有更优的经济和生态效益。

不同采收期辽东楤木叶的功能成分及其抗氧化活性

为给辽东楤木(Aralia elata)适时采收提供理论依据,以栽培型辽东楤木为试验材料,分析了辽东楤木叶在不同采收时期(S1时期,2023年4月10日;S2时期,2023年4月30日;S3时期,2023年5月20日;S4时期,2023年6月9日)的生物量、光合色素含量、总酚和总黄酮含量、抗氧化能力。同时,建立了高效液相色谱(HPLC)的检测方法,测定辽东楤木皂苷A、辽东楤木皂苷V、辽东楤木皂苷X的含量,并且基于高效液相色谱-质谱代谢组学技术,对比分析了不同采收期辽东楤木在次生代谢产物上的差异。结果表明:(1)辽东楤木叶鲜质量、干质量、光合色素含量均随着生长而增加,在S4时期达到最大值(;2)总酚和总黄酮含量在S1时期达到最大值(1.36 mg·g^(-1)、29.38 mg·g^(-1));(3)S1时期DPPH自由基清除能力最强(IC_(50)为0.262 g·L^(-1)),S2时期ABTS自由基清除能力最强(IC_(50)为0.511 g·L^(-1));(4)辽东楤木皂苷A的含量在S4时期达到最大值,为12.90 mg·g^(-1),辽东楤木皂苷V和辽东楤木皂苷X在S2时期的含量显著高于其他时期,分别为1.53、3.30 mg·g^(-1);(5)共鉴定了24种酚类代谢物,4个时期的酚类化合物总量分别为64.84、119.31、101.95、89.32 mg·g^(-1),其中C6C1骨架化合物(原儿茶酸、龙胆酸),C6C3C6骨架化合物(芦丁),C6C3骨架化合物(咖啡酸)在S2时期显著积累。综上所述,综合考虑功能成分含量、抗氧化活性和食用性认为,S2时期为最适宜的采收时间。

紫秋山葡萄加工品质提升与酿造工艺优化

【目的】从葡萄的品质提升和工艺优化这两个维度上,研究GS-1叶面肥对紫秋山葡萄营养品质,以及不同工艺参数对葡萄酒口感的影响,从而为酿造出优质的山葡萄酒提供理论与技术支持。【方法】在葡萄转色期后分3次喷施不同浓度的GS-1叶面肥,定期检测紫秋山葡萄总酸、总糖含量的变化,计算糖酸比(成熟度系数),明确紫秋山葡萄的最佳加工采收期;葡萄采收后,通过比较不同叶面肥浓度对紫秋山葡萄果实原花青素、游离花色苷、总酚、总类黄酮等主要营养品质的影响,确定GS-1叶面肥的最佳施用浓度;以感官评价和理化指标为评判标准,对菌种、发酵温度、时间、接种量4个因素进行单因素试验,并在单因素试验的基础上进行正交试验,优化山葡萄酒的发酵工艺。【结果】(1)紫秋山葡萄在福建闽南地区适宜的加工采收日期为9月下旬,其采收成熟度系数(M值)可以达到21以上;(2)紫秋山葡萄在喷施稀释300倍GS-1叶面肥后可显著提升营养品质,其总糖、原花青素、游离花色苷、总酚、总类黄酮的含量比对照分别提高3.79%、26.99%、35.41%、13.91%、24.12%;(3)优化后的紫秋山葡萄酒发酵的工艺参数为菌种JP2酿酒酵母,发酵温度24℃,接种量1%,发酵时间10 d。【结论】通过喷施GS-1叶面肥和成熟度监测,可以提升闽南地区紫秋山葡萄的品质;通过对紫秋山干红葡萄酒酿造工艺进行优化,提升了紫秋山葡萄酿造品质,为紫秋山葡萄酒行业的发展提供数据支持。