Effect of Production Process and Raw Material Quality on Carotenoid Content in Pumpkin Pulp and Its Optical Properties

Pumpkin (Cucurbita) is a melon, fodder, and oilseed crop. It is rich in macro- and micronutrients that give it its antibacterial, antiparasitic, antioxidant, prooxidant, anticancer, antidiabetic, analgesic, and anti-inflammatory properties. Various storage and preservation methods make it possible to preserve and stabilize the initial quality of pumpkin. This article describes the changes in the optical properties and carotenoid content in pumpkin pulp depending on the cultivar and the production method. The research featured fresh pumpkins of six mid-season varieties, i.e., Rossiyanka, Ulybka, Kustovaya Oranzhevaya, Gribovskaya Zimnaya, Zimnaya Sladkaya, and Altaiskaya 47. The colorimetric methods made it possible to determine the color differences during storage while the carotenoid content was analyzed by chromatography. The data obtained underwent statistical processing. The dry puree samples were obtained by conventional drying and enzymolysis with Amilorizin and Protozyme. The pumpkin variety affected the lightness indices, the b* color coordinate, and the browning index, as well as the content of lutein and trans-β-carotene in the puree. The production method affected the a* color coordinate, the color difference, the saturation, and the hue angle, as well as the content of violaxanthin, α-carotene, and cis-β-carotene. Compared with the conventional drying, the enzymolysis samples demonstrated better lightness indices, smaller a*, b*, and saturation changes, a higher content of violaxanthin, lutein, α-carotene, trans-β-carotene, and a lower content of cis-β-carotene. The best optical properties belonged to the cultivars of Rossiyanka, Ulybka, and Kustovaya Oranzhevaya. The optimal carotenoid content belonged to Ulybka, Gribovskaya Zimnyaya, Rossiyanka, Zimnyaya Sladkaya, and Altaiskaya 47. Some significant direct correlations were registered between the content of trans-β-carotene and the a* changes; violaxanthin correlated with a* and b*; α-carotene correlated with a*. An inverse correlation occurred between the content of cis-β-carotene and the changes in a* and b*. The results may help pumpkin farms to improve the production of high-quality pumpkin puree with stable optical properties.