Quality assessment and variety classification of seed-used pumpkin by-products: Potential values to deep processing

Seed-used pumpkin (SUP) is known as a traditional popular crop, which is mainly processed for seeds. However, the by-products (49 times the amount of seeds) were disposed directly into the field as waste. In this study, potential values of seed-used pumpkins' by-products (SUPBs, peel and pulp) as food resource were investigated. Physico-chemical, nutritional, and aroma profile of ten varieties of SUPBs were characterized, and variety differences were also distinguished. Peel "a*" value, water, fructose, crude fat, sucrose, and Ca contents were the 6 characteristic indicators of SUPBs which screened through correlation analysis, principal component analysis (PCA), and PCA-X model. Comprehensive evaluation of physico-chemical, nutritional, and aroma profile, four varieties by-products (Jf8#, Nf8#, Rbf#, and Rf9#) were always characterized into Cluster Ⅰ. Other varieties were classified into Cluster Ⅱ based on aroma profile. However, two varieties by-products (Db1# and Xn1#) presented significant differences from others (Db2#, Db3#, Db4#, and Myxc2#) in physico-chemical and nutritional indices, they were classified as Cluster III and IV, respectively. Db1# had the highest nutritional value of soluble solid (11.78 ºBx), pectin (1,166.15 mg/ 100 g), total carotenoid (19.57 mg/ 100 g), and total sugar (13.69 g/ 100 g). Among all the SUPBs, Db1# had a relatively higher nutritional value, which was suitable as food resource for deep processing.