苦瓜啤酒的生产技术

文章介绍了苦瓜基汁苦瓜啤酒的工艺流程,阐述了生产过程的操作步骤和要求,并提出了苦瓜啤酒的质量标准。     

赣北早熟梨有效酸与近红外光谱的相关性研究

通过分析赣北早熟梨有效酸含量与近红外光谱的相关性,试图采用近红外光谱技术对赣北早熟梨有效酸进行无损检测,建立赣北早熟梨有效酸含量和光谱的数学模型。结果表明：利用近红外光谱分析预测赣北早熟梨有效酸含量的方法理想。     

不同处理对梨酵素抗氧化活性的影响

本实验以新鲜的宁陵金顶谢花酥梨为原料,通过自然发酵、酵母菌发酵、乳酸菌发酵制作梨酵素,对比切丁处理和打浆处理对梨酵素发酵过程中理化指标和抗氧化活性的影响。结果表明,切丁处理后,酵母菌发酵优于自然发酵和乳酸菌发酵,梨酵素的还原力为2.40,多酚含量为35.57 mg·mL^-1,羟自由基清除率为90.35%,DPPH自由基清除率为81.31%,ABTS自由基清除率为92.17%。打浆处理后,自然发酵比菌种发酵效果好,酵素液的还原力为2.36,多酚含量为34.81 mg·mL^-1,羟自由基清除率为88.89%,DPPH自由基清除率为80.17%,ABTS自由基清除率为91.74%。     

异菌脲在梨和土壤中残留量的测定方法

建立了异菌脲在梨和土壤中气相色谱分析方法。梨、土壤样品用乙腈提取,Florisil固相萃取小柱净化,淋出液浓缩后用正己烷定容,气相色谱仪电子捕获器检测。试验结果表明,异菌脲的含量与峰面积之间呈线性关系,异菌脲的最小检出量为0.005ng。对于梨样本,异菌脲最低检测量为0.01mg/kg,添加平均回收率为94%～107%,变异系数为3.2%～6.5%;对于土壤样本,异菌脲最低检测量为0.01mg/kg,添加平均回收率为98%～110%,变异系数为4.0%～10.5%。结果表明该残留分析方法的灵敏度、准确度、精密度等均符合农药残留检测的要求。     

京津冀地区梨始花期模拟及花期冻害特征分析

目的 建立京津冀地区梨始花期模拟模型,对梨树花期内冻害发生特征进行分析,为当地梨的生产管理和冻害风险防范提供支撑。方法 文章基于春暖模型构建京津冀地区梨始花期模拟模型,结合1980—2020年该地区171个气象站逐日气温数据,重构各站点逐年梨始花期,研究梨树花期冻害发生特征。结果 （1）构建的梨始花期模拟模型能较好地模拟各物候观测站点的梨始花期年际变化,模型内部检验和交叉检验的均方根误差的平均值分别为2.10 d和2.85 d,决定系数的平均值分别为0.87和0.75,该模型可推广到研究区其他站点;（2）研究区梨始花期日序自南向北逐渐推迟,各站点多年平均始花期在4月2日至5月19日;1980—2020年梨始花期呈现出显著提前的趋势,各站点提前趋势在0.4~5.3d/10年;（3）研究区梨树花期内轻、中、重度冻害频次均呈现出北多南少的空间分布,且41年间大多站点表现为增多的趋势。结论 全球变暖背景下,京津冀地区梨树始花期有所提前,花期内冻害增多,仍需对梨树花期冻害加强防范。研究结果可以指导当地梨树种植和提供防灾减灾政策支撑。     

Invasive plants – friends or foes? Contribution of prickly pear (Opuntia ficus-indica) to livelihoods in Makana Municipality,Eastern Cape,South Africa

The negative impacts of invasive alien species on the environment are well documented. However, despite the predominantly negative perceptions associated with invasive species, it is evident that a number of these plants have been part of the landscape for generations and have numerous commercial and non-market uses. Consequently, there is a need for research that considers the impact of invasive species on the livelihoods and well-being of local communities. The authors investigated the contribution that the trade in prickly pear (Opuntia ficus-indica), an invasive alien species, makes to the household income streams of poor trading households. The research highlights the apparent conflict of interests and trade-offs that exists between local traders, for whom the sale of the prickly pear provides a livelihood source, and the South African Government, who are actively seeking to remove the plant from the landscape.     

基于GIS适宜性评价的农业用地结构优化 ———以永商镇为例

利用数字高程模型(DEM)、土壤数据、土地利用数据并借助GIS与数学模型对永商镇早熟梨用地适宜性进行了综合评价.结果表明,永商镇适宜种植早熟梨的用地面积约435.28hm2,占农业用地总面积的25.21％.借助GIS软件和适宜性最小耗费表面模型对早熟梨种植用地的空间分布进行了分析,当最大拓展宽度达到56m时,符合农业规划中多目标模型要求的333.33hm2种植规模.     

Traceability adoption at the farm level: An empirical analysis of the Portuguese pear industry

Traceability is becoming a condition to operate in European food markets. Retailers impose more stringent standards than what is mandatory. An example is EurepGAP, a quality standard for good agricultural practices that imposes traceability as a main obligation. This research investigates the choice of traceability at the farm level in the Portuguese pear industry. Results suggest that in this industry farm-level adoption of EurepGAP traceability is best explained by the choice to sell to the United Kingdom (UK). For farmers selling to the UK, the odds of choosing the EurepGAP traceability level are significantly linked to membership in particular producer organizations, farm productivity, producing products under a protected designation of origin (PDO), and farmer’s age. While retailers and farmer organizations seem to drive traceability, policy adjustments may be required to reduce adoption costs upstream and extend compliance among producers that sell directly to consumers and market independently.     

冻藏对草莓与皇冠梨食用品质的影响

本试验以草莓和皇冠梨为研究对象,对其进行-25℃冻藏处理,以明确冻藏对两种水果失重、维生素C含量、可溶性糖含量和可滴定酸度的影响.结果表明,冻藏后两种水果的重量有微小变化;冻藏24 h后,与鲜样相比,草莓维生素C含量和可滴定酸度均显著增加,冻藏草莓的维生素C含量是鲜样的1.17倍,可溶性糖含量增加16.00％,糖酸比无...     

壳聚糖处理对鲜切金秋梨的防褐变效果研究

本文以金秋梨为试验材料,研究1%的壳聚糖溶液浸泡处理对鲜切金秋梨的防褐变效果。试验中用壳聚糖对鲜切金秋梨进行处理,晾干后用保鲜膜包裹,置于4℃下贮藏,每2 d测定维生素含量、总酚含量、多酚氧化酶(PPO)和过氧化物酶(POD)活性,贮藏末期(12 d),对褐变指数进行测定。结果表明,壳聚糖处理能够延缓金秋梨贮藏过程中维生素和总酚含量的下降,抑制多酚氧化酶(PPO)和过氧化物酶(POD)活性,降低褐变指数(对照组褐变指数是壳聚糖处理组的1.9倍),起到有防褐变的效果。壳聚糖防褐变效果的研究,为生物保鲜剂的研发提供了参考。