Preparation and Quality Evaluation of Nutritionally Enriched Jam Made from Blends of Indian Blackberry and Other Fruits

Jamun (Syzygium cumini) is a tropical, underutilized fruit which is highly perishable in nature. It is a good source of vitamin C, tannins, gallic acid and anthocyanins and its beneficial effects are mostly due to the presence of bioactive compounds (pigments and phenolic compounds) in it. Due to astringent and fibrous nature, preparation of jam from jamun pulp is quite difficult, but other fruits (apple and kiwifruit) can be incorporated in it to improve its quality. This study aims to develop jam from blends of jamun with other fruits and analyse various physico-chemical, nutritional, textural and sensory properties. It was found that physico-chemical properties of jams were not found to vary greatly, but the jamun–kiwifruit jam was found to have fairly high amount of antioxidants(46.75 ± 0.67%), tartaric acid (26.24 ± 0.02 mg/100g sample), ascorbic acid (0.08 ± 0.01 mg/100 g sample) and lactic acid (23.95 ± 0.01 mg/100g sample) and lowest amount of 5-hydroxymethyl-2-furaldehyde (0.38 ± 0.04 mg/100 g sample). Jamun jam and jamun–kiwifruit jam possessed the texture required for jam while jamun–apple jam was found to be a relatively harder gel. Jam made with jamun and kiwifruit pulp was found to have highest acceptability on the basis of sensory evaluation.     

涪陵区无公害杨梅的栽植优势及发展趋势

杨梅不仅是一种经济价值较高的农产品,而且也是退耕还林过程中增收较快的经济树种之一,涪陵区的自然条件适宜杨梅种植,因此,大力发展优质杨梅栽培技术是涪陵区调整农业产业结构的一个突破点。近几年,涪陵区杨梅加工业发展迅速,杨梅栽植优势明显,具有广阔的发展前景。本文结合重庆市涪陵区的实际情况,对无公害杨梅栽植的优势进行了分析,并结合涪陵区的种植现状提出了优化无公害杨梅种植的措施。     

1-MCP对猕猴桃后熟质地品质的临界浓度研究

为探究1-甲基环丙烯(1-MCP)对猕猴桃后熟质地品质作用效果的差异,寻找适宜的1-MCP临界使用浓度,研究通过应用质地多面分析(TPA)测试法,以"贵长"猕猴桃为试材,比较不同处理果肉质地品质差异和好果率,分析各质地参数之间相关性,并且用主成分分析法进行综合评价。结果表明:0.75μL/L和0.50μL/L 1-MCP处理均能够更好地保持猕猴桃货架期的好果率;果实的咀嚼性、弹性、硬度、回复性和凝聚性相互之间都有较好的相关性,但黏着性与其他指标相关性较差,所以用咀嚼性、弹性、硬度、回复性和凝聚性作为评价猕猴桃果实质购性能的主要参数。与对照比较,6种浓度1-MCP处理中,0.75μL/L 1-MCP的处理对维持猕猴桃后熟质地品质效果最好,其次是0.50μL/L1-MCP处理,两组处理均能够延缓果实硬度并且使果实正常后熟。而高浓度(1.50μL/L和1.25μL/L)的1-MCP对猕猴桃果实后熟质地的保持效果较差,出现"僵尸果"现象。另外综合主成分分析显示,货架末期(9 d)时,不同处理猕猴桃质地品质从高到低的排列顺序为:0.75μL/L0.50μL/L1.00μL/L0.25μL/L1.25μL/L1.50μL/L0μL/L。因此,从经济和后熟质地品质考虑,采后用0.50～0.75μL/L1-MCP来处理猕猴桃对保持果实质地品质的效果最好。     

“红阳”猕猴桃采后存放过程中的品质变化

以云南曲江栽培的“红阳”猕猴桃为试材,同期从市场上购买“黄金果”“楚红”“徐香”“亚特”4个品种作为对照,对存放过程中的果实硬度、可溶性固形物、维生素C、黄酮、还原糖、总糖、总酚等指标进行测定,以研究“红阳”猕猴桃存放过程中的品质变化。结果表明:存放期间,与口感相关的硬度、固形物、还原糖、总糖含量均呈下降趋势,而与功能相关的维生素C、总酚、总黄酮含量呈下降趋势,且中华系列品种“红阳”“楚红”“黄金果”的下降幅度较美味系列品种“徐香”“亚特”高,表明在中华猕猴桃系列品种的采后、销售过程中,冷链的采用非常必要,即使是在食用阶段,冰箱冷藏是避免有效组分降解的有效手段。结果同时表明,从营养、口感综合角度讲,当猕猴桃果实达到熟化食用阶段时,应尽快食用,否则会影响其营养价值。在未来的猕猴桃品质选育中除注重风味、口感指标外,培育高含量功能物质降解缓慢品质将是一个重点。此外,应加强储藏过程中避免有效保存功能物质的降解变化研究。     

红肉猕猴桃果实发育期不同果肉部位比较转录组分析

红肉猕猴桃中果皮和内果皮在果实发育不同时期色泽变化模式有显著差异,但目前对于其内在的分子调控机制尚不清楚。本研究中,利用高通量测序技术,对红肉猕猴桃(‘红实2号’)中果皮与内果皮4个不同发育时期(开花后0 d, 28 d, 75 d, 157 d,分别标注为T1时期, T2时期, T3时期, T4时期)的样本进行转录组测序。经去除低质量数据后,得到Clean reads数目为2 192～4 331万,检测到的基因数目为24 607～29 170个。在(log2 Ratio)≥1和FDR<0.05阈值下,中果皮和内果皮在T2、T3、T4时期检测到的差异基因数目分别为1 880个、4 799个、7 346个和4 31个、1 493个、7 700个。KEGG分析显示这些差异表达基因被富集到68个代谢途径,包括DNA复制、RNA转运、蛋白质输出、植物激素信号转导、类黄酮生物合成、花青素合成、淀粉与蔗糖的代谢等。此外我们还鉴定到13个花青素合成相关基因差异表达,大部分基因的表达量随果实的发育呈现下降趋势,这一结果与花青素含量变化模式相吻合。本研究不仅深化了对猕猴桃果实成色差异机理的认识,还对今后的彩色猕猴桃选育种工作有一定的帮助。     

A rapid extensigraph protocol for measuring dough viscoelasticity and mixing requirement

The extensigraph is particularly useful in characterizing dough viscoelastic properties; however, testing throughput for standard method is low due to the prerequisite for farinograph water absorption, long dough resting and milling to prepare large amounts of flour. Therefore, a rapid extensigraph method was developed that reduced sample size (165 g wheat) for milling and more than tripled throughput. Wheat is milled in Quadrumat Junior mill with a modified sieving system. The resulting flour (100 g) was mixed with a pin mixer at constant water absorption to allow the evaluation of wheat genotypes at the absorption level they are expected to perform. Dough was subsequently stretched by an extensigraph after 15 min of floor time and 30 min resting. Strong correlations for extensigram R_max (r > 0.93), extensibility (r > 0.64) and area (r > 0.88) were found for the proposed method compared to the standard method. Mixing parameters (time and energy) obtained during dough preparation provided further information about dough strength and mixing requirement. By significantly reducing sample size requirement and increasing testing throughput, this rapid extensigraph method can be widely adopted in milling and baking industry and meets the need for a fast evaluation of dough strength in breeding trials.     

Inhibition study of red rice polyphenols on pancreatic α-amylase activity by kinetic analysis and molecular docking

This study sought to investigate the possible inhibition mechanism of red rice polyphenols (RRP) on pancreatic α-amylase (PA) activity. RRP showed strong inhibition against PA activity and the half-inhibitory concentration (IC₅₀) value was 3.61 μg/mL. The fluorescence quenching of PA by RRP was a combination of static quenching and dynamic quenching. RRP could aggregate with PA and the physiochemical properties of the aggregates were closely related to the concentration of RRP. Kinetic analysis suggested that the inhibition mode of RRP on PA was reversible inhibition, which was a mixing of competitive inhibition and noncompetitive inhibition. Molecular docking speculated that RRP could form hydrogen bonds with PA by binding to the catalytic active sites (ASP197, GLU233 and ASP300) and the microenvironments of TRP58 and TRP59 were altered, thus inhibiting PA activity.     

矮型猕猴桃(Actinidia chinensis)"赣猕5号" 的离体培养研究

对中华猕猴桃矮型种质“赣猕5号”进行了离体培养与快繁研究。以带腋芽的茎段为外植体,在MS 6-BA1,0 mg/L NAA0.1 mg/L培养基上进行诱导。诱导出的不定芽分别在MS ZT1.0 mg/L 6-BA 1.0mg/L NAA0.2 mg/L IBA0.1 mg/L和W h ite IBA0.5 mg/L培养基上进行增殖和生根培养,增殖系数可达4.6,生根率可达94%。完整小植株经炼苗、移栽后的最终成活率为95%左右。     

氮肥对红三叶和鸭茅草地生产性能影响的研究

本文对红三叶和鸭茅单、混播草地对施氮肥的反应情况进行了研究，发现氮肥对鸭茅的株高、分蘖及产草量具明显的促进作用，而红三叶对氮肥的反应则不十分明显。同时施肥后，单播处理牧草的产量增幅比混播处理大。试验结果还表明，鸭茅和红三叶产量与施氮肥量均呈指数关系。通过对单播鸭茅和混播草地总产对氮肥的反应规律进行分析，可以把混播草地对氮肥的利用情况及氮肥对该草地中红三叶固氮作用影响的变化规律分为３类：第１类为混播草地投入最低氮肥量，草地生产力较低，此时红三叶能提供较高氮素价值量；第２类，混播草地投入中等氮肥量，草地生产力中等，但红三叶提供氮素的价值量减小；第３类，投入较高氮肥量，但红三叶失去提供氮素价值。本试验显示，从经济效益角度考虑，对混播草地以少施氮肥为好，特别是在０～０．３ｔ／ｈａ范围内较为适宜。     

不同稳定剂对胭脂萝卜红色素稳定性的影响

天然胭脂萝卜红色素属于花青素类化合物,性质不稳定。笔者以新鲜胭脂萝卜(Raphnussativuscv.)肉质根为原料,提取胭脂萝卜红色素,选择常用的5种稳定剂对其稳定性进行研究,从而确定出最佳的稳定剂及其用量。研究结果发现0.03%维生素C、0.03%谷氨酸、0.03%柠檬酸能明显地延缓其颜色变化,0.03%维生素C 0.03%柠檬酸的组合对该色素的稳定效果最佳;进一步研究确定维生素C和柠檬酸的最佳用量分别为0.04%和0.08%。