果品冷冻损伤的高光谱定量表征方法研究

It is a necessary condition for improving the fruit’s storage quality and reducing freezing damage to quantitatively describe of the relationship between freezing damage and temperature load. Due to the limitation of the measuring means, more research in this area are staying in the observation and phenomenon-based qualitative analysis at present. The project intends to introduce hyperspectral technology into experimental mechanics field. A hyperspectral experimental mechanics test system with in-situ temperature load applied function will be developed. The mathematical model of the hyperspectral data will be bulit. The analysis methods of hyperspectral data and fast algorithm will be proposed. The mathematical model of hyperspectral characteristics of typical fruits under temperature load will be established. The digital image correlation method will be improved. The relationship among the hyperspectral characteristic parameters, mechanical deformation and damage variable will be characterized. A quick test method for typical fruits’ freezing damage will be developed. The degree of injury and damage mechanism of typical frozen fruits will be analyzed from the perspective of experimental mechanics. Thus, quantitative relationship between the temperature load and fruit damage is expected to be established based on hyperspectral experimental curves. The research results not only enrich the testing technology in the field of experimental mechanics, but also has important significance to deeply understand of the principle of freezing damage, to determine chilled and frozen technical indicators and to prevent hypothermia and frost damage.

定量地描述果品的冷冻损伤与温度载荷之间的关系是减少冷冻损伤、提高果品贮藏品质的必要条件，由于测量手段的制约目前这方面的研究多停留在基于现象的观察和定性分析。本项目拟发展高光谱实验力学测试新技术，研制具有原位施加温度载荷功能的高光谱力学实验测试系统，建立高光谱谱线数学模型，提出高光谱特征峰分析方法与快速算法，建立典型果品在温度载荷作用下的高光谱特征数学模型，改进数字图像相关方法，表征光谱特征参数与力学变形和损伤变量之间的关系，发展典型果品冷冻损伤表征的快速测试方法，从实验力学角度分析典型果品的损伤程度和损伤机理，进而基于高光谱实验曲线建立温度载荷与果品损伤之间的定量关系。研究成果不仅丰富了实验力学领域的测试技术，而且对深入理解果品冷冻损伤机理，确定果品冷藏和冻藏技术指标，预防低温冻害具有重要的意义。

果品的冷冻冷藏是果品保鲜的常规手段。在冷冻冷藏过程中，由于冰晶体的存在、生长会给果品带来损伤，从而降低果品的品质。在这种情况下，损伤的定量表征以及与温度载荷之间的定量关系成为该领域的关键性基础力学问题。然而，由于缺乏合适的测量手段而制约了这些问题的有效解决。高光谱成像技术凭借其定性、定量以及定位的能力，已经成为食品质量和安全检测、现代农业等领域最为活跃的一种检测手段。本项目，搭建高光谱力学实验测试系统。对不同高光谱图像预处理方法进行了研究，开发了适合果品在温度载荷下特性表征的高光谱图像分析方法，定量分析了温度对果品高光谱谱线的影响。建立了南果梨在温度载荷作用下高光谱特征的可溶性固形物和硬度的数学模型。进行了基于高光谱成像技术的圣女果冷害研究，并根据冷害程度进行分级。发展了果品冷冻损伤表征的快速测试方法，从实验力学角度分析典型果品的损伤程度和冷冻条件之间的关系。研究成果不仅丰富了实验力学领域的测试技术，而且对深入理解果品冷冻损伤机理，确定果品冷藏和冻藏技术指标，预防低温冻害具有重要的意义。