Drying temperature, endogenous antioxidants and capsaicinoids affect carotenoid stability in paprika (red pepper spice)

• Published in: Journal of the science of food and agriculture 2006-11, Vol.86 (14), p.2450-2457
• Main Authors: Daood, H.G, Kapitány, J, Biacs, P, Albrecht, K
• Format: Article
• Language: English
• Subjects: Acids; antioxidant activity; Antioxidants; Aroma and flavouring agent industries; Biological and medical sciences; capsaicin; capsaicinoids; Capsicum annuum; carotenoids; chemical analysis; chemical composition; Chromatography; drying; drying temperature; endogenous sources; fatty acids; Food engineering; Food industries; food processing; food processing quality; food storage; Fundamental and applied biological sciences. Psychology; General aspects; oxidative stability; paprika; Pigments; plant pigments; processing; storage quality; Studies; vitamin C; vitamin E
• ISSN: 0022-5142; 1097-0010
• DOI: 10.1002/jsfa.2639

The major carotenoids and carotenoid esters in Capsicum annuum L. during thermal dehydration of pepper and storage of the ground product (paprika) were examined with special focus on the role of endogenous antioxidants such as vitamins E and C and capsaicinoids, the pungent materials in hot spice red pepper. A high-performance liquid chromatographic (HPLC) method was developed to achieve excellent separation and accurate detection of different carotenoid classes including free xanthophylls, monoesters, carotenes and di-esters. The newly developed method included gradient elution on a reversed-phase column with increasing proportions of isopropanol. The results indicated that presence of capsaicinoids in pungent pepper had a favourable effect on the stability of carotenoids during thermal drying. Among various di-esters those of lutein and zeaxanthine, as well as the mono-ester of β-cryptoxanthin were more stable than those of capsorubin and capsanthin, pointing to the possible role of epoxide and carbonyl groups in the susceptibility of carotenoids. An Arrhenius plot for degradation of carotenoids, tocopherols and ascorbic acid as a function of drying temperature showed linear relationships for all components, with ascorbic acid being the most sensitive. During storage in a refrigerator for 3 months the paprika showed high degradation of all the examined carotenoids particularly in samples prepared from pods dried at high temperatures (90 and 100 °C). An exception was for β-cryptoxanthin mono-ester and violaxanthin di-esters in a non-pungent variety. The amounts of these carotenoids lost during storage were slightly affected by the change in drying temperature. Strong correlation was found between retention of colour in stored paprika and the initial content of ascorbic acid, but not with that of tocopherols or capsaicinoids.