Finite Element Analysis and Near-Infrared Hyperspectral Reflectance Imaging for the Determination of Blueberry Bruise Grading

Abstract

Bruising of the subcutaneous tissues of blueberries is an important form of mechanical damage. Different levels of bruising have a significant effect on the post-harvest marketing of blueberries. To distinguish different grades of blueberry bruises and explore the effects of different factors, explicit dynamic simulation and near-infrared hyperspectral reflectance imaging were employed without harming the blueberries in this study. Based on the results of the compression experiment, an explicit dynamic simulation of blueberries was performed to measure the potential locations of bruises and preliminarily divide the bruise stages. A near-infrared hyperspectral reflectance imaging system was used to detect the actual blueberry bruises. According to the blueberry photos taken by the near-infrared hyperspectral reflectance imaging system, the actual bruise rates of blueberries were obtained by using the Environment for Visualizing Images software for training and classification. Bruise grades of blueberries were divided accordingly. Response surface methodology was used to determine the effects of ripeness, loading speed and loading location on the blueberry bruising rate. Under the optimized parameters, the actual damage rate of blueberries was 1.1%. The results provide an important theoretical basis for the accurate and rapid identification and classification of blueberry bruise damage.

Experiment and finite element simulation of friction factor and stack damage between blueberries

“…The compression speed of the texture analyzer was set to 0.5 mm/s. According to previous studies, blueberries were heavily damaged when compressed to a distance >2.5 mm (Zheng et al, 2022), and the heavy damage was easily observed. In this experiment, blueberries subjected to a force of 5 N would be compressed to a distance >2.5 mm.…”

“…It was known from the study of Section 3.2 that the stack method of unit cell d was the best. As shown in Table 6, the maximum browning area of ULB in unit cell was 32.1%, the blueberry was slightly damaged (Zheng et al, 2022). According to commercial standards, sales were not affected when the damaged area of the blueberry did not reach 35%, the maximum force that caused the damaged area was 5.3 N. If the blueberries were stacked in the best way, the ULB in the bottommost unit cell was subjected to the greatest force.…”

“…It was known from the study of Section 3.2 that the stack method of unit cell d was the best. As shown in Table 6, the maximum browning area of ULB in unit cell was 32.1%, the blueberry was slightly damaged (Zheng et al, 2022). According to commercial standards, sales F I G U R E 8 Effect of calyx orientation on stacking damage in blueberries.…”

Mechanical damage characteristics and nondestructive testing techniques of fruits: a review

“…To distinguish different grades of blueberry bruises, Zheng et al (2022) used near-infrared hyperspectral reflectance imaging to get the actual bruising rate of blueberries. The actual damage rate of blueberries was 1.1% with the optimized parameters.…”

Modeling of soluble solid content of PE‐packaged blueberries based on near‐infrared spectroscopy with back propagation neural network and partial least squares (BP–PLS) algorithm

“…A total of 146 blueberries in good shape and with similar freshness and no visual defects (cuts, shrivel, etc.) were selected for the experiment, which lasted for 10 days (Zheng et al, 2022). To keep the blueberries fresh, the samples were stored in a refrigerator at 5 • C until the experiments were conducted.…”