An active pH-sensitive film based on pectin-sodium alginate-xanthan gum composite film (PAX) was prepared, containing blueberry anthocyanin extract (BAEs), to monitor the freshness of blueberries. The effects of different contents of BAEs on the microstructure and physical properties of intelligent polysaccharide films were comprehensively evaluated. It was found that 75BAEs-PAX film had a solid response to pH value and showed different and easily distinguishable colors at different pH values. In addition, when the freshness of blueberries stored at different temperatures (-1 ??C, 4 ??C, 10 ??C, 15 ??C, 25 ??C) was monitored, the color of 75-BAEs-PAX film changed from purple to light pink from neutral to acidic environment, which was consistent with the change of pH value of blueberries from fresh to spoilage. The Arrhenius equation verified that the difference between the activation energy of the indicator film and the blueberry quality was less than 25 kJ/mol. Therefore, the 75-BAEs-PAX film can be used as an indicator film for blueberries freshness monitoring. In this study, the freshness of blueberries was monitored by BAEs, and the purpose of using ontology to monitor ontology was achieved. The freshness of blueberries was visualized during storage and transportation, which could effectively reduce the waste of blueberries. In the future, the method of ontology monitoring ontology could be extended to other foods.

[目的]研究冰温状态下蓝莓鲜果质量损失率与质构参数随时间的变化规律及其相关性,为蓝莓鲜果采后品质预测及感官评价提供理论依据.[方法]以'北村'蓝莓为试验材料,(-1±0.5)℃为冰温组,(4±0.5)℃为对照组,分别对2种温度状态下蓝莓鲜果质量损失率及硬度、脆性、弹性、咀嚼性、内聚性和黏附性等6项质构参数进行测定,通过数据拟合与线性回归反映出蓝莓鲜果质量损失率与质构参数随时间的变化规律,进行相关性分析确定与蓝莓鲜果质量损失率呈显著相关的质构参数.[结果]冰温状态下,蓝莓鲜果质量损失率Y与时间X0的拟合模型为Y=0.19736exp(X0/5.85047)-0.1845,呈指数式增长,增长趋势明显小于对照组;蓝莓鲜果各项质构参数在试验期间随时间呈不同程度的下降趋势,且均优于对照组.蓝莓鲜果冰温下质量损失率Y与硬度X1、脆性X2、咀嚼性X3等3项质构参数呈显著负相关(P<0.05),构建回归方程为Y=4.772-0.011X1-0.017X2-0.306X3.[结论]冰温贮藏更有助于蓝莓鲜果品质的保持.冰温状态下,蓝莓鲜果质量损失率及各质构参数与时间构建的回归模型拟合精度较高.确定了冰温状态下蓝莓鲜果的硬度、脆性和咀嚼性是与蓝莓鲜果质量损失率变化相关的主要质构参数.

为了提高蓝莓保鲜效果,该研究制备含有不同质量浓度鱼腥草提取液的抗菌复合膜.实验测试薄膜的拉伸强度、断裂伸长率、光线透过率、水蒸气透过率和抗菌率,并将蓝莓果实涂膜处理后存储于4℃冷藏条件下,测定各组蓝莓果实的硬度、失重率、总可溶固体物(TSS)、可滴定酸(TA)、花青素含量、抗坏血酸(Vc)含量、丙二醛(MDA)含量和多酚氧化酶(PPO)活性等指标.研究发现:当鱼腥草提取液浓度为0.06 g/mL时,抗菌率提高至77.40％,薄膜拉伸强度提高至21.92 MPa,断裂伸长率为17.13％,光线透过率为80.20％,水蒸气透过率为2.55×10-10 g/(m·s·Pa),综合性能表现最佳;经20 d贮藏后,蓝莓果实的硬度为1.17 kg/cm2,失重率为5.80％,可溶性固形物为0.13％,可滴定酸降低至4.57×10-2 mmol/g,花青素含量提高至2.40 mg/g,Vc含量为19.50 mg/100 g,丙二醛含量为13.30μmol/g,多酚氧化酶活性为3600 U/(min·mg).研究表明:添加0.06 g/mL鱼腥草提取液能有效提升抗菌复合膜的综合性能,对蓝莓具有较好的保鲜效果,可以有效地维持蓝莓果实品质,延长货架期近10 d.

测定在4、15、25℃储藏温度下蓝莓的硬度、失重率、腐烂率和可滴定酸含量4种指标品质随时间的变化情况,结合试验人员对蓝莓感官指标的评分,建立蓝莓消费者整体满意度快速预测模型,提升蓝莓消费者的购买满意度.结果表明,蓝莓质量随储藏时间呈下降趋势,较低的储藏温度能减缓品质下降幅度;对参数进行逐步回归分析,腐烂率、色泽和气味3项指标对拟合模型不具有显著性(P>0.05),去除后得消费者满意度的快速预测模型.本研究结合品质客观变化规律和消费者主观评分,建立的整体满意度预测模型与品质变化情况拟合度较高,为消费者快速判断蓝莓品质、提升消费满意度提供理论依据和经验参考.

新冠肺炎疫情发生以来,人们的生活、工作和学习受到了严重的影响.为了解新冠肺炎疫情对科技期刊的影响,本文选择五种具有代表性的林业科技期刊,对这些期刊2019年出版的栏目、文章类型、作者单位等三方面进行统计分析,预测未来两年内可能会面临的科研方面稿源紧缺问题,并提出相应的建议,如遴选适合的选题、征集约稿、总结沉淀以前的研究成果等,为办刊人提供参考.