Changes of GLCM texture and antioxidant increase during freezing of pumpkin
Y Kristianto1, W Wignyanto2, B D Argo3, and I Santoso2

1 Department of Nutrition, Polytechnic of Health, Ministry of Health, Besar Ijen 77c, 65112, Malang, Indonesia
2 Department of Agroindustrial Technology, Faculty of Agricultural Technology, University of Brawijaya, Veteran, 65145, Malang, Indonesia
3 Department of Agricultural Engineering, Faculty of Agricultural Technology, University of Brawijaya, Veteran, 65145, Malang, Indonesia

Abstract

GLCM (gray level co-occurrence matrix) textural features are rarely extracted from SEM (scanning electron microscopy) food images to study the effect of food processing on cellular microstructure and bioactive contents. Using the GLCM approach, the current study attempted to use textural information from pumpkin SEM images to obtain detailed cellular degradation caused by freezing treatment and to find their relationship to the antioxidant content. High dimensional textural features of the samples were obtained during image processing and subjected to multivariate analysis. The increased of antioxidant activity due to freezing of pumpkin was used to create a vector factor to indicate the membership class of individual pumpkin samples. Following freezing, the flavonoid content of the pumpkins increased ranging from 15.27% to 70.39%. Freezing also caused formation and increased of several volatile compounds detected by GCMS. The PCA (principal component analysis) results showed that two components were sufficient to explain most variance of the dataset. Further supervised sPLS-DA (sparse partial least squares-discriminant analysis) indicated a clear separation of samples based on their antioxidant levels, suggesting an existing relationship between the texture and antioxidant. In conclusion, GLCM textures are important features where their major variation can be accurately explained by the antioxidant activity changes as a result of freezing treatment.

Keywords: pumpkin, freezing, GLCM, PCA, PLS-DA, antioxidant

Topic: AGRICULTURAL PRODUCT TECHNOLOGY